Oxford Handbook of Clinical Surgery (4 edn)
Annotate
Cite
Endotracheal intubation 186
Cardioversion 188
Defibrillation 190
Venepuncture 192
Intravenous cannulation 194
Arterial puncture and lines 196
Insertion of central venous catheter 198
Chest drain insertion 200
Management of chest drains 202
Pericardiocentesis 204
Cricothyroidotomy 206
Nasogastric tube insertion 208
Urethral catheterization 210
Suprapubic catheterization 212
Paracentesis abdominis 214
Rigid sigmoidoscopy 216
Local anaesthesia 218
Intercostal nerve block 220
Endotracheal intubation
Key facts
Indicated in cardiac arrest, serious head injury, certain acute respiratory and trauma settings, and prior to many surgical operations.
Effective bag-and-mask ventilation is better than ineffective attempts at endotracheal intubation in the arrest setting.
Except in a dire emergency, this procedure should not be performed without expert supervision.
Equipment
Empty 10mL syringe.
Endotracheal tube (ET; size 8–9 for females and 9–11 for males).
Laryngoscope.
Ribbon to secure tube, lubricating jelly.
Connection tubing, Ambubag, and O2 (cylinder or wall connection).
Working wall suction, tubing, and Yankauer.
Preparation
Move bed forward so that you can stand behind patient's head and raise it so that you are working a comfortable height. Put on gloves.
Elective setting. Pre-oxygenate the patient; attach pulse oximeter to patient, connect Ambubag to 100% O2, use effective bag-and-mask ventilation for 2–3min to achieve O2 saturations >95%.
Emergency setting. Suction mouth (aspiration is major risk, bag-and-mask ventilation with Ambubag, and 100% O2).
Check laryngoscope light works and blade opens and ET tube cuff inflates and deflates with 10mL syringe.
Remove any dentures and suction again any saliva and secretions.
Extend the neck.
Insert the laryngoscope, pushing the tongue to the left.
Advance the scope anterior to the epiglottis and pull gently, but firmly, upwards to expose the vocal cords.
Insert the lubricated ET tube between the cords into the trachea.
Confirm correct positioning of the tube by observing chest movements and listening over lung bases and stomach.
Progressively inflate the cuff and attach ventilation equipment.
Confirm correct cuff inflation by listening for whistling or bubbling in the larynx suggesting air leak and secure the tube in place with ribbon.
Patients not in cardiac arrest or who maintain a gag reflex will need anaesthetizing prior to oropharyngeal intubation, i.e. administration of inducing agent plus muscle relaxant: this should be done only under supervision of a trained anaesthetist.
The best setting to learn intubation is preoperatively in the anaesthetic room of a theatre with good supervision in controlled conditions.
Tips and pitfalls
Oesophageal intubation. Potentially fatal if not recognized. Always check for bilateral breath sounds, chest movement, absence of stomach sounds, pulse oximetry, blood gas, and capnography, if available. Bag- and-mask ventilation is the safest and most effective way to oxygenate a patient if you are not experienced at endotracheal intubation.
Cannot visualize vocal cords. Ask for ‘cricoid pressure’—firm downwards pressure from an assistant over the cricoid can help bring cords into view. Some patients are ‘difficult intubations’ just because of their particular anatomy and build; the safest way to maintain their airway is to avoid repeat attempts at intubation, resume bag-and-mask ventilation, and wait for senior help.
Inadequate cuff pressure. Too little and airway not protected from aspiration, too much and pressure injury can result in erosion or stenosis. The balloon should feel as firm as your fingertip.
Key revision points—anatomy of the lower pharynx and larynx (Fig. 4.1)
(a) Diagram of the larynx as seen at intubation. (b) Correct position of inflated endotracheal tube cuff.
Cardioversion
Key facts
Synchronized direct current (DC) cardioversion is the treatment of choice for tachyarrhythmias compromising cardiac output (CO), such as AF and supraventricular tachycardia (SVT) and for AF refractory to chemical cardioversion.
Is it indicated? Is the patient still in AF?
Is it safe (see 
p. 189)?
Either AF has lasted <24h; or
The patient must have had at least 6 weeks of formal anticoagulation; or
The patient must have a TOE excluding intracardiac thrombus.
Is the patient ready?
The potassium should be 4.5–5.0 (otherwise, repeat AF likely).
The INR, if anticoagulated, should be >2.0.
The patient should have a valid consent form.
The patient should be starved for 6h.
DC cardioversion for AF and SVT
Patient should be anaesthetized: some anaesthesiologists prefer not to intubate, managing the airway with a bag and mask. You can either use adhesive external defibrillator pads which remain fixed to the patient until the procedure is completed or handheld paddles and gel pads. As soon as the anaesthesiologist is happy:
Expose chest.
Place pads on chest in position shown in Fig. 4.2: the aim is to direct as much of the current as possible through the heart.
Place three ECG electrodes on the patient as shown and connect to the defibrillator so that an ECG trace is visible.
Switch defibrillator on and turn dial on to appropriate power setting (100J, 200J, 360J).
Press the ‘SYNC’ button and ensure that each R wave is accented on the ECG: failure to do this can mean that a DC shock is delivered while the myocardium is repolarizing, resulting in VF. Check that the ‘SYNC’ button is on before every shock for AF.
If you are using handheld paddles, hold them firmly on the gel pads.
Perform a visual sweep to check that no one is in contact with the patient at the same time as saying clearly, ‘Charging. Stand clear’.
Press the ‘CHARGE’ button.
Press the ‘SHOCK’ button when the machine is charged.
If the shock has been delivered successfully, the patient's muscles will contract violently: anyone in contact with the patient risks experiencing an electric shock.
Check the rhythm.
If still AF, press the ‘CHARGE’ button and repeat the sequence.
Using defibrillators. (a) Correct positioning for defibrillation and cardioversion. (b) Alternative positioning for synchronized DC cardioversion.
Complications of DC cardioversion
Common pitfalls
Failure to deliver a shock
Check that the defibrillator is switched on and adequately charged. Check that the correct power setting has been selected. Change the machine.
Failure to cardiovert
Check the latest available serum K+ was 4.5–5.0. Check that the correct power setting has been selected. Replace gel pads with fresh ones. Reposition the patient on their side and the pads as shown and try two further shocks at 200J (see Fig. 4.2). Don't start at too low a power setting: each shock leaves the myocardium less sensitive to further shocks. There is some evidence that 360J as the first power setting results in less myocardial damage and a better conversion rate than multiple shocks at lower power settings.
Defibrillation
Key facts
Defibrillation is the treatment of choice for VF and pulseless VT.
Biphasic defibrillators cycle current direction every 10ms: the same amount of current (roughly 12amp and 1500V) is delivered, but with less energy (200J compared to 360J in older monophasic models), reducing the risk of burns and myocardial damage.
External defibrillation for VF and pulseless VT
Do not delay defibrillation for manoeuvres such as intubation, massage, or administration of drugs.
Expose chest.
Place gel pads on chest in position shown in Fig. 4.2: the aim is to direct as much of the current as possible through the heart.
Switch defibrillator on and turn dial on to appropriate power setting (200J for external defibrillation).
Press ‘CHARGE’ button.
If you are using handheld paddles instead of adhesive external defibrillator pads, place them firmly on gel electrodes and hold.
Perform a visual sweep to check that no one is in contact with the patient at the same time as saying clearly, ‘Charging. Stand clear’.
Press the red/orange ‘SHOCK’ button on the paddles.
If the shock has been delivered successfully, the patient's muscles will contract violently: personnel in contact with the patient may experience an electric shock.
Check the rhythm: if VF, charge again and repeat the sequence.
If the rhythm changes to one compatible with an output, check the pulse before proceeding further.
Common pitfalls
Failure to deliver a shock
Check that the defibrillator is switched on and adequately charged. Check that the correct power setting has been selected. Check that the ‘SYNC’ button is off if you are trying to defibrillate VF. Change the machine and paddles.
Failure to defibrillate
Exclude causes of intractable VF, i.e. failure to effect rhythm changes compatible with an output despite repeated attempts. In internal defibrillation, decompress the heart using massage (with the flows down if you're on cardiopulmonary bypass). Double-check that the rhythm is not in fact asystole. Epinephrine, lidocaine, or amiodarone may improve chances of converting VF and maintaining rhythm.
Venepuncture
Key facts
This is a mandatory skill to learn for all doctors, but many patients will have ‘difficult’ veins and regular practice is needed.
Indications
Obtaining venous blood samples for laboratory analysis, venesection.
Equipment
Tourniquet.
23G or 21G needle, vacutainer holder.
Syringe (appropriate size: 10–20mL).
Alcohol swabs.
Appropriate laboratory sample tubes.
Cotton wool ball and tape.
Pillow if the vein looks difficult.
Most hospitals now have vacuum tube systems as an alternative to the ‘needle and syringe’ approach for obtaining blood samples.
Preparation
Apply tourniquet above the elbow and inspect the arm for suitable engorged veins. Place arm on a pillow, especially if you may be a while.
Method
Clean the skin thoroughly with alcohol at the site of access.
Tether the skin distal to the site with the thumb of your left hand.
Pass the needle obliquely through the skin at a point approximately 2mm distal to the point of planned entry to the vein.
Advance the needle slowly until a ‘give’ is felt as the vein is entered and a ‘flashback’ is seen in the needle: push vacutainer onto holder.
Aspirate the desired amount of blood while holding the barrel of the syringe firmly.
Release the tourniquet before gently withdrawing needle and syringe.
Apply pressure to the site to arrest any bleeding. Do not assume the patient can help with this, e.g. stroke patients.
Tips and pitfalls
Poor veins. If the patient is cold and the samples non-urgent, place the arm in warm water as this may aid venodilation. Veins on the dorsum of the hand may be the only ones readily available; try using a smaller or butterfly needle to obtain samples. Aspirate gently using a syringe on a butterfly needle, not a vacutainer as this may collapse veins.
Obese patients. Try the dorsum of the hand or the radial aspect of the wrist, access may be easier here.
Failed attempts. Repeated failed attempts will distress the patient and demoralize the doctor! Ask someone to help. If the samples are extremely urgent, a femoral stab may be the best option for obtaining blood samples, e.g. during cardiac arrest.
IV cannulae. If blood samples and IV access are needed, obtain samples through the cannula—simple and saves the patient another needle, although be careful to draw blood slowly as haemolysis is more common via a cannula.
Sample bottles and request forms. Ensure these are labelled correctly and the appropriate tests are ordered. If in doubt about a particular investigation, seek advice from a senior or the laboratory.
Blood cultures. Ensure that the skin is swabbed thoroughly. Do not touch the skin again unless sterile gloves are worn. Once the sample is taken, change the needle before transferring the sample to the appropriate culture bottle. Document whether the patient was on antibiotics at the time of the sample and ensure the sample is not placed in the fridge during transfer to the lab.
Superficial venous system.
Cephalic vein. Commences from the lateral end of the dorsal venous network overlying the anatomical snuffbox, ascending the lateral and anterolateral aspect of the arm to the deltopectoral groove, piercing the clavipectoral fascia to join the axillary vein.
Basilic vein. Commences from medial end of the dorsal venous network, ascending along medial and anteromedial aspect of forearm, piercing the deep fascia to join the venae comitantes of the brachial artery which eventually join the axillary vein.
Median cubital vein. Connects these two veins in the cubital fossa.
Deep system: venae comitantes of ulnar, radial, and brachial artery, which flow into the axillary vein.
Most common sites for phlebotomy and cannulation are:
Dorsal venous network.
Median cubital vein.
Cephalic vein in the forearm.
Intravenous cannulation
Key facts
A similar skill to that of simple venepuncture, but needs plenty of practice to become competent. If having difficulty, observe a few experts in action; an ideal setting is in the anaesthetic room of theatres.
Indications
Venous access for administration of IV fluids, blood, or IV drugs.
Equipment
Tourniquet.
Cannula (20G or 18G) (see Table 4.1).
Adhesive dressing/tape.
Alcohol swabs.
5mL syringe containing 0.9% saline or heparinized saline.
IV fluid bag with giving set, if necessary.
| Colour | Size | Flow (mL/min) | Use |
|---|---|---|---|
Blue | 22G | 31 | Small veins, paediatrics |
Pink | 20G | 55 | Slow infusions |
Green | 18G | 90 | IV fluids, drugs, transfusions |
White | 17G | 135 | |
Grey | 16G | 170 | Rapid IV fluids, emergencies |
Brown | 14G | 265 |
| Colour | Size | Flow (mL/min) | Use |
|---|---|---|---|
Blue | 22G | 31 | Small veins, paediatrics |
Pink | 20G | 55 | Slow infusions |
Green | 18G | 90 | IV fluids, drugs, transfusions |
White | 17G | 135 | |
Grey | 16G | 170 | Rapid IV fluids, emergencies |
Brown | 14G | 265 |
Preparation
Apply tourniquet above or below the elbow and inspect the arm for suitable engorged veins.
Method
Clean the skin thoroughly at the site of access; put on sterile gloves.
Identify a suitable vein.
Tether the skin distal to the proposed site of puncture.
Pass the cannula obliquely through the skin at a point approximately 2mm distal to the point you wish to enter the vein.
Advance the cannula smoothly until the vein is entered: a ‘give’ will be felt and a ‘flashback’ seen in the hub of the cannula.
Hold the hub of the needle with one hand and advance the cannula into the vein, while maintaining skin fixation until the cannula is well into the vein.
Remove the tourniquet and press on the vein proximal to the cannula as the needle is removed. Apply the screw cap to the end of the cannula.
Secure the cannula in place with a dressing.
If the cannula is not going to be used immediately, flush with heparinized saline.
Tips and pitfalls
Poor veins, obese patients, and failed attempts. See ‘Venepuncture’ section (see p. 192).
Agitated or fitting patients. Try not to place the cannula over a joint as these tend to become easily dislodged or ‘tissued’.
Secure the cannula. Cannulae are all too easily dislodged because of poor fixation to the skin. Use of two cannula dressings (one placed above and one below) and a bandage is often needed.
Hairy arm. Shaving the skin at the planned cannula site seems tedious, but will allow the cannula to be secured adequately.
Non-dominant hand. Placing the cannula in the non-dominant hand, if possible, will allow the patient a little bit more freedom and may prevent the cannula becoming dislodged easily.
Fragile veins. Tends to be a problem in elderly or debilitated patients. Try using a smaller cannula; the dorsum of the hand is often ideal site.
Poor peripheral access. In some patients with multiple collapsed or damaged veins, alternative cannula sites may have to be considered, e.g. feet. If peripheral cannulation becomes impossible, a central line will have to be considered.
Blood transfusion. If blood is being given IV, then an 18G or 16G cannula will be needed.
Complete failure to cannulate
Is a cannula necessary?
Can IV medication or fluids be omitted until elective central/long line insertion is possible?
Can medication or fluids be given orally or via NGT?
Discuss with microbiology if antibiotics are involved: changing route of administration often requires appropriate changes in antibiotic.
Fluid and insulin regimes can be modified to be given subcutaneously if desperate.
Many painkillers and antiemetics can be given PR or IM.
Ask another member of your team to try: sometimes a ‘fresh’ pair of hands is all that is needed.
If no one in your team can site the cannula, ask the on-call anaesthetist if they can help, but remember they are not a cannulation service and do not ask them until you have asked every member of your team unless it is an emergency!
If peripheral access is impossible or required for a long time (e.g. IV antibiotic regimes for infected prostheses), consider:
Elective PICC line insertion (long-term line inserted electively by specialist nurse into the basilic vein);
Elective central line insertion: this should be done in an anaesthetic room rather than on ward and during daytime hours ( p. 198).
Femoral line insertion (less ideal as this site is more prone to line sepsis).
Arterial puncture and lines
Key facts
Arterial puncture is needed to sample ABGs; if serial measurements are required or continuous monitoring of arterial blood pressure is needed, then an arterial line should be sited (see p. 128).
Equipment
Arterial puncture only requires a 22G needle on the green 5mL blood gas syringe, an alcohol swab, and cotton wool.
Arterial line insertion equipment generally comes prepacked in sterile kits, but if unavailable, you will need:
Two 20G arterial cannulas with guidewire.
Connectors, transducer, and three-way tap.
2mL 1% lidocaine.
5mL syringe and blue needle.
10mL saline.
Skin prep, sterile gloves, small drape.
Gauze swabs.
Preparation
Explain the procedure to the patient if appropriate.
It is good practice to perform Allen's test (see below) to demonstrate that the ulnar arterial supply to the hand arcades is intact.
For radial artery cannula insertion, place the forearm on a pillow so that the wrist is dorsiflexed; for femoral artery insertion, abduct and flex the hip slightly.
Landmarks
Radial artery. Lies between tendon of flexor carpi radialis and head of radius.
Femoral artery. Lies midway between the anterior superior iliac spine and the symphysis pubis.
Technique
Prepare and check equipment and prep skin; put on sterile gloves.
Infiltrate local anaesthetic in the skin, but avoid distorting the anatomy.
Palpate pulse between two fingers for 2–3cm.
Pass cannula at 45° into skin.
Once the cannula is in situ, aspirate and flush via the three-way tap.
Transfixion technique (see Fig. 4.3)
The cannula is passed through both artery walls, the needle completely withdrawn, and the cannula then withdrawn slowly until flashback occurs, at which point it is advanced into the artery.
Partial transfixion technique
The cannula is advanced until flashback stops and the needle withdrawn while holding the cannula steady which is then advanced into the artery.
Artery not transfixed
The cannula is advanced carefully in 0.5mm increments until flashback is seen, at which point the catheter is slid off the needle in the artery.
Guidewire
A guidewire is useful where it is possible to get flashback, but difficult to advance the catheter up the artery.
Complications
Ischaemia, thrombosis, bleeding, damage to radial and median nerve. Inadvertent intra-arterial injection of drugs.
Allen's test
Allen's test demonstrates a patent palmar collateral circulation: the patient clenches his fist to exclude blood from palm and the doctor firmly compresses both ulnar and radial pulses while patient opens his palm, which should be blanched. The doctor releases the ulnar compression whilst still occluding the radial pulse: the palm becomes pink in <5s if there is good collateral supply from the ulnar artery (see p. 647). About 3% of people do not have a collateral palmar supply and hand ischaemia is a real risk if the radial artery is cannulated.
Transfixion technique of arterial cannula insertion.
Insertion of central venous catheter
Key facts
Indications are listed on p. 128. Cannulae can be single or multi-lumen, sheaths (for insertion of pulmonary artery (PA) catheters and pacing wires), tunnelled, or long lines.
Equipment
Appropriate central venous (CV) catheter.
Ultrasound probe and condom if ultrasound is to be utilized.
Enough three-way taps for all individual lumens.
10mL 1% lidocaine.
10mL syringe.
Blue needle and a green needle.
20mL saline.
2 or 3/0 silk on a large handheld needle.
11-blade scalpel.
Skin prep, sterile drape, sterile gloves, and gown.
Gauze swabs, dressing.
Preparation
Explain the procedure to the patient if appropriate.
Ask a nurse to be present.
Patient's ECG and pulse oximetry should be continually monitored.
Ensure that there is adequate light, a space behind the bed which you can work in, and that it is possible to place the bed in Trendelenberg.
Landmarks
Internal jugular vein
Central approach. Apex of triangle formed by clavicular and sternal heads of sternocleidomastoid (SCM) muscle, aiming the needle towards the opposite nipple.
Posterior approach. Point where line drawn horizontally from the cricoid cartilage to the lateral border of the clavicular head of SCM, aiming the needle towards the sternal notch.
Anterior approach. Medial border of the sternal head of SCM, aiming needle towards ipsilateral needle.
Subclavian vein
Advance the needle at 45° to the junction of the outer and middle third of the clavicle 1–2cm, then direct needle towards sternal groove.
Technique
There are numerous techniques: only one is described below.
Prep the patient, gown, and glove.
Drape so that all landmarks are exposed.
Palpate the carotid pulse.
Infiltrate local anaesthetic around the planned puncture site.
Spend 2–3min laying out the equipment in the order of use, secure three-way taps to central line, and turn to closed position.
Ask the nurse to place the bed in 10–20° of Trendelenberg.
Ballot the internal jugular vein.
Using aseptic technique and a 20G catheter on a 10mL syringe, enter the skin at 45° as described in ‘Landmarks’ section (see p. 196).
On aspirating venous blood, remove the syringe and needle, but leave the catheter in situ: check that the puncture is venous, not arterial, by attaching manometry tubing, letting it fill with blood, and holding it up—level should fall if venous.
Pass the guidewire down the catheter, keeping hold of it at all times.
Once an adequate length of wire is in place, remove the catheter over the wire, and apply pressure to the vein.
Make a 3mm nick in the skin over the wire with a scalpel.
Pass the dilators over the wire through the skin, but not into the vein.
Remove the dilators, apply pressure, and pass the CV cannula over the wire into the vein up to an appropriate length.
The wire normally protrudes through the brown (proximal) lumen of a triple lumen line which should therefore be left open.
Aspirate, flush, and close all lumens and suture the catheter to the skin.
Check that there is a satisfactory pressure trace if a transducer is used.
Chest X-ray (CXR) to identify pneumothorax.
Complications
Immediate
Damage to nearby structures (carotid artery puncture, pneumothorax, haemothorax, chylothorax, brachial plexus injury, arrhythmias), air embolism, loss of guidewire into right side of heart, haematoma.
Late
Sepsis, thromboembolism, arteriovenous (AV) fistula formation.
In the upper neck, the internal jugular vein may be cannulated as it lies within the carotid sheath. The important relations here are:
Sheath is just anterior to the anterior border of SCM.
Carotid artery is anteromedial.
Vagus nerve lies between the two.
In the lower neck, the internal jugular vein may be cannulated as it lies behind the SCM. The important relations are:
Vein lies 45° lateral and 45° inferior to the junction of the sternal and clavicular heads of the SCM.
The pleural lies inferomedial.
The subclavian artery lies lateral.
The internal jugular drains into the brachiocephalic vein; on the right, this is shorter and drains more vertically into the superior vena cava (SVC), making the internal jugular vein cannulae easier to pass into the SVC.
Chest drain insertion
Key facts
There are three main options for most patients with pleural effusions or pneumothoraces that need intervention:
Needle thoracentesis. Used for first-time treatment of simple effusions or pneumothoraces with low likelihood of recurrence.
Pigtail thoracostomy. A 16G tube inserted using modified Seldinger technique; good for simple pneumothorax or effusion.
Chest tube. Large bore tube inserted, either blunt (recommended) or using trocar to treat tension pneumothorax, recurrent pneumothorax, haemothorax, or empyema. Indications are listed below.
Indications (British Thoracic Society guidelines)
Pneumothorax.
In any ventilated patient.
Tension pneumothorax after initial needle relief.
Persistent or recurrent pneumothorax after simple aspiration.
Large secondary spontaneous pneumothorax in patients over 50y.
Malignant pleural effusion.
Empyema and complicated parapneumonic pleural effusion.
Traumatic haemopneumothorax.
Post-operative, e.g. thoracotomy, oesophagectomy, cardiac surgery.
Equipment
28G intercostal drain.
Underwater seal containing water to up to mark.
Connection tubing.
Line clamp.
Roberts or other instrument for blunt dissection.
20mL 1% lidocaine.
10mL syringe.
Blue needle and a green needle.
20mL saline.
2 or 3/0 silk on a large handheld needle.
11-blade scalpel.
Skin prep, sterile drape, gloves and gown, gauze swabs.
Preparation
Explain the procedure to the patient if appropriate; recheck side on X-ray and sign consent form.
Ensure continual monitoring of pulse oximetry.
Position the patient at 45° with the arm abducted.
Technique
Usual insertion site is the 5th intercostal space in the mid-axillary line.
It may extend anteriorly to the anterior axillary line.
Prep and drape the skin, gown, and glove.
Infiltrate site for tube insertion with local anaesthetic, ensuring anaesthesia at all layers down to and including parietal pleura and the periostem of the ribs posterior to the line of the incision.
A 2cm transverse skin incision is made and the intercostal space (see Fig. 4.4) is dissected bluntly.
Place purse string suture and suture to secure drain now.
Firmly and carefully pass a blunt-ended clamp over the lower rib through the pleura (you will feel a pop as the tissue gives) and spread to widen the hole.
Place a finger into the pleural space to ensure there are no adhesions.
Pass a chest tube without a trocar into the pleural space, guiding it superiorly for a pneumothorax and basally for a haemothorax.
Secure drain with at least one strong suture and connect immediately to an underwater seal and place on –20mmH2O suction.
Anatomy of the intercostal space.
Tips and pitfalls
Misplacement. Subcutaneous (more common in obese patients), intraparenchymal; always check for an air leak on coughing and a swing to confirm that the chest tube is in the pleural space, particularly if no effusion draining.
Trauma to other structures (diaphragm, spleen, liver, heart, aorta, lung parenchyma, intercostal arteries). Entry sites too low (common mistake, remember you are much less likely to cause damage if you are too high than if you are too low), too posterior or trocar used instead of blunt dissection. Stay on the top of the lower rib to avoid injuring the intercostal artery and causing a haemothorax.
Surgical emphysema. Implies there is massive air leak not being drained effectively by the chest tube. Is the tube blocked, kinked, pulled out so that holes are communicating with skin, in too far so that it is wedged in fissure, in the subcutaneous tissue rather than the pleura?
Wound infection, empyema.
Pain.
Management of chest drains
Technique of insertion is described on p. 200. This section describes the types of chest drainage systems available and basic protocols for managing chest drains.
Types of drainage system
Underwater seal
Underwater seal drains used to consist of three bottles connected by tubing, the third bottle providing suction control determined by the depth the connection tube penetrated below the water level in the bottle. Now most hospital wards have reliable high volume, low pressure wall suction, which means that simple, lightweight, single underwater seal bottles can be used instead of the cumbersome three-bottle systems. The system has to be kept upright.
Underwater seals are suitable for any condition requiring chest drainage.
They can be used with or without suction.
Suction is usually –2–5kPa.
Heimlich valves
The Heimlich valve is a one-way flutter valve within rigid tubing. It can be connected to a standard chest drain. The system allows air and fluid out of the chest cavity, but prevents both from entering. The system has to be open to air, which makes collecting liquid effluent more difficult.
Heimlich valves are usually considered in patients with a permanent air leak for whom surgery is not appropriate and for whom the main goal of therapy is discharge to home or palliative care.
Portex bag
The Portex bag was designed as an ambulatory chest drainage system. It consists of a Heimlich valve within a drainage bag which has a capacity of about 1500mL and can be emptied intermittently. This drainage system cannot be connected to suction.
These drains are indicated in patients with chronic pleural collections, in whom surgery is not appropriate.
As the systems are airtight, an air leak is a contraindication.
Suction
Almost all conditions can be safely managed by an underwater seal system without suction, but suction helps to reinflate the acutely collapsed lung and improves drainage of fluid. There is a huge range in surgeons’ preferences for suction protocols: the points below represent commonly used protocols.
1kPa = 7.5mmHg = 10cmH2O.
Suction should be high volume, low pressure: approximately 2–3kPa.
Blocked suction tubing or a blocked filter at the wall is the equivalent of clamping the drain; have a low threshold for suspecting either.
Most patients with chest drains should be on suction; the exceptions to this are patients with pneumonectomies who are not placed on suction.
Ventilated patients cannot generate their own negative intrapleural pressures and therefore all chest drains in these patients, with the exception of post-pneumonectomy drains, should be placed on suction.
It is usually safe for a patient with an underwater seal on wall suction to mobilize off suction for brief periods.
Discontinue suction in extubated patients after 24–48h when the lung is fully inflated on CXR and there is no air leak (the drain does not bubble when the patient coughs).
Suction is unlikely to secure expansion in the lung that has been collapsed chronically; it is most effective in the immediate post-operative period.
Clamping drains
More patients have died as a result of clamped drains than unclamped drains. The practice of clamping chest drains during transfer is a dangerous one. It reveals a failure to understand how a modern underwater seal drain works as well as reflecting outmoded practice that dates back to the time of TB when drain bottles contained caustic sterilizing fluid that could drain back into the patient if lifted above the level of the chest during transfer. The only indications for clamping a chest drain are below.
Post-pneumonectomy
The post-pneumonectomy chest drain is usually clamped for an hour at a time and unclamped briefly to allow blood to drain. Leaving the drain unclamped risks causing mediastinal shift towards the pneumonectomy side and cardiovascular compromise. The drain is usually removed on day 1 post-operatively.
Massive haemothorax or effusion
If more than 1500mL of fluid is drained immediately on insertion of a chest tube and/or the patient appears haemodynamically compromised as a result of drainage, it is appropriate to clamp the drain for a brief period. In massive haemothorax, the effect is to attempt to tamponade the bleed, buying a little time to organize surgical exploration. In a massive effusion, this allows time for the lung to expand without re-expansion pulmonary oedema and to reduce mediastinal shift caused by rapid drainage.
Decision making in long-term drains
Occasionally, a surgeon may decide to see if a patient with a chronic effusion or air leak can manage without a drain by clamping the drain. Tension pneumothorax may result from doing this in a patient with an air leak. Such patients must be observed frequently for any sign of respiratory or haemodynamic compromise, surgical emphysema, or radiological evidence of lung collapse, and if any of the above occur, the drain must be unclamped and placed on underwater seal. If the patient tolerates the clamp for 24h, it is usually possible to remove the drain.
Pericardiocentesis
Key facts
Occasionally used, usually by cardiologists under fluoroscopic guidance, to relieve acute pericardial tamponade.
There is almost no indication, outside emergencies in an under-equipped setting, to perform this procedure blindly without fluoroscopic or echo guidance.
In an emergency due to trauma where tamponade is due to active bleeding, clots will prevent effective needle aspiration and a thoracotomy, sternotomy, or subxipoid incision, depending on the circumstances, should be performed.
Equipment
Pericardiocentesis needle or catheter.
10mL 1% lidocaine.
10mL syringe.
18G catheter.
20mL saline.
2 or 3/0 silk on a large handheld needle.
11-blade scalpel.
Skin prep.
Sterile drape.
Sterile gloves and gown.
Gauze swabs.
Preparation
Explain the procedure to the patient where appropriate.
Ensure patient has continual ECG monitoring.
Landmarks
One half centimetre below and to the left of the xiphoid, aiming at 45° to skin, pointing at left shoulder or nipple.
Technique (see Fig. 4.5)
Prep and drape the skin, gown, and glove.
Infiltrate 5mL 1% subcutaneous lidocaine and make a nick in the skin.
To begin, identify the needle entry site 0.5cm immediately to the left of the xiphoid tip.
Insert the catheter, applying continuous aspiration in the direction described above.
After needle entry into the skin and sc tissue, watch the ECG monitor (or echo/fluoroscopic screening monitor if available) as the needle is slowly advanced; if there are ectopics or changes in the ST segments, stop and withdraw the needle a few mm.
When in contact with the pericardium, advance the needle a few cm into the pericardial space.
If ST segment elevation is present, this indicates contact with the myocardium and the needle should be withdrawn slightly into the pericardial space where no ST segment elevation should be seen.
When in the pericardial space, withdraw needle from catheter and aspirate fluid.
If the tamponade is successfully reduced, right atrial pressures should be decreased, cardiac output should increase and pulsus paradoxus should disappear.
Echocardiography, normally transoesophageal, is required to show reduction in the size of the collection and improvement in the signs of tamponade such as compression of right atrium and ventricle.
Clotted blood cannot be evacuated in this way; a patient with tamponade from a haemopericardium needs emergency surgical evacuation, usually via a sternotomy if trauma is suspected.
Complications
Cardiac puncture.
Laceration of a coronary artery.
Air emboli.
Cardiac arrhythmias.
Haemothorax.
Pneumothorax.
Infection.
Technique of pericardiocentesis. (a) Landmarks for needle. (b) Pericardiocentesis.
Cricothyroidotomy
Indications
Emergency need for a surgical airway
Major maxillofacial injury.
Oral burns.
Fractured larynx.
Need for tracheal toilet in the extubated patient.
Patient peri-arrest.
Use the landmarks described below.
Omit local anaesthetic infiltration, cut-down, and dissection.
Pass a 12G (brown or larger) needle directly though the cricoid membrane.
Oxygenate using jet insufflation until a formal airway can be established.
Equipment
Minitracheostomy, size 6.0 ET tube or 12G cannula in emergencies.
Artery forceps.
10mL 1% lidocaine.
10mL syringe.
Blue needle and a green needle.
20mL saline.
2 or 3/0 silk on a large handheld needle.
11-blade scalpel.
Skin prep.
Sterile drape.
Sterile gloves and gown.
Gauze swabs.
Preparation
Explain procedure to the patient where appropriate.
The trauma patient's C-spine should be immobilized in the neutral position.
Landmarks
The cricoid membrane is a small diamond-shaped membrane, palpable just below the prominence of the thyroid cartilage.
Technique (see Fig. 4.6)
Prep and drape, put on sterile gloves.
If the patient is conscious and maintaining their own airway, infiltrate local anaesthetic using aseptic technique.
Stabilize the thyroid cartilage with the left hand.
With your right hand, make a 2cm transverse incision (smaller for minitracheostomy) through the skin overlying the cricothyroid membrane and then straight through the cricothyroid membrane.
Now turn the scalpel blade 90° within the airway so that it acts as a temporary retractor.
Place an artery forceps through the incision and open it, remove the scalpel, and insert a size 6.0 ET tube.
Suction the tube, secure, and connect to a source of oxygen.
Some minitracheostomy kits use the Seldinger technique; aspirating air freely is a sign that the needle is in the trachea and that a guidewire can be gently passed down the lumen.
Complications
Bleeding.
Loss of airway.
Recurrent laryngeal nerve injury.
Vocal cord injury.
Technique of cricothyroidotomy. (a) Structures involved. (b) Incision. (c) Keeping cricothyroidotomy patent. (d) Inserting mini-thyroidostomy.
Nasogastric tube insertion
Key facts
Nasogastric tubes (NGT) are used to decompress the stomach and to administer enteral feeding and drugs in patients that cannot manage oral intake. Enteral feeding is covered on p. 136.
Inadvertent placement of an NGT into the bronchial tree can cause aspiration pneumonia or even respiratory arrest if it is then used to administer feeds or other fluids; placement must always be systematically checked (see p. 209) on a CXR prior to use.
Never replace an NGT in an oesophagectomy patient without discussing it with a senior; you risk pushing the tube through the fresh anastomosis.
It is worth learning how to place these; usually you will get a call when the person who normally places them has failed.
Indications
Intestinal obstruction (wide bore or Ryle's tube).
Paralytic ileus.
Perioperative gastric decompression.
Enteral feeding (fine bore tube).
Equipment
NGT (sizes 10–12 French).
Gloves.
Lubricating gel.
Lignocaine throat spray.
NG collection bag.
Litmus paper.
Stethoscope.
Sticky tape.
Preparation
Chill NGT in fridge prior to passing. This stiffens the tube and makes it easier to pass.
Explain the procedure to the patient where appropriate.
Position the patient, preferably in a sitting position, with the head tilted slightly forward.
Method
Wash hands and put on sterile gloves.
Lubricate the tip of the NGT with gel.
Pass the tube horizontally along the floor of the nasal cavity, aiming towards the occiput.
As the tube engages in the pharynx, ask the patient to swallow and the tube should pass into the oesophagus.
Some advise getting the patient to take a sip of water, hold it in their mount while you introduce the tube and then swallow; this introduces an aspiration risk and many patients are not able to cooperate to this extent because of pain, nausea, confusion, etc.
Advance the tube approximately 40–60cm.
Check the position of the tube as follows:
Aspirating gastric contents which will turn blue litmus red; and
Insufflate 20mL air down the tube; if in stomach, should produce bubbling which can be heard on auscultation over the stomach; and
All feeding tubes must be X-rayed prior to use to exclude inadvertent bronchial intubation; you must be able to follow the NGT all the way down to the fundus of the stomach on the CXR. Always double-check you cannot see the tube in the bronchial tree or pleura. This is the only true confirmation that NGT is in stomach.
Tape tube securely to nostril and attach end to bag/suction.
Tips and pitfalls
Patient has problems swallowing. Ask the patient to swallow sips of water as the tube is passed.
Constant coiling in the mouth. Tube may be soft; cool in the fridge.
Resistance to passing. There may be an anatomical reason for this, e.g. oesophageal stricture. The tube may need to be passed under X–ray control.
Tube migration. Just because the tube was in the correct position yesterday does not mean it is today; patients pull at these, work them out of the oesophagus with their tongue into a coil at the back of the throat. If called to assess, always look at the back of the pharynx (‘Open your mouth and say Ah’) and get a CXR.
Aspiration of tube feeds. In the hypoxic or obtunded patient on NGT feeds, think of aspiration. Stop the feeds. Sit the patient up and give O2. Assess the tube position. If you suspect aspiration (tube feeds visible in mouth, coughing up feeds, tube in bronchus on CXR), call for senior help; the patient may need a bronchoscopy and/or intubation.
Urethral catheterization
Key facts
Foley catheters are useful to monitor urine output hourly (renal failure, fluid balance) and in immobile patients.
Catheterization of female patients is usually performed by nursing staff; it is useful to learn the technique as you will be asked to try if they fail!
Indications
Perioperative monitoring of urinary output.
Acute urinary retention.
Chronic urinary retention.
Aid to abdominal or pelvic surgery.
Incontinence.
Male catheterization
Equipment
Foley catheter (size 12–20G, 14G most commonly used).
Dressing/catheter pack containing drapes.
Cleansing solution, sterile gloves (two pairs).
Lidocaine gel.
Gauze swabs, drainage bag and/or universal specimen pot for midstream urine (MSU).
Preparation
Consent the patient, explaining the procedure.
Lay patient supine.
Expose the genital area and cover with a sterile drape with a hole in it.
Method
Clean hands and put on sterile gloves.
Pick up the glans penis with your non-dominant ‘dirty’ hand through the hole in the drape; the other hand will be your ‘clean’ hand.
Holding a swab soaked in sterile saline with your clean hand, retract the foreskin and clean the urethral orifice and glans thoroughly so your gloved fingers only touch the swab, not the glans penis.
Without letting go of the penis, discard the swab and pick up the sterile lidocaine gel with your clean hand and inject into the urethra.
Still holding the penis in a vertical position, introduce the catheter with the clean hand and advance gently for approximately 10cm.
Lower the penis to lie horizontally and advance the catheter fully (through the prostatic urethra) up to the hilt.
Inflate the balloon now in the bladder via the smaller catheter channel with the 10mL sterile water; some catheters have an integral bulb of air which, when squeezed, inflates the balloon.
NEVER inflate the balloon until the catheter is fully inserted as this risks inflating the balloon within the prostatic urethra, causing urethral rupture; ideally you should see urine before inflating the balloon.
Attach a catheter bag firmly to the catheter.
Replace the foreskin to avoid paraphimosis.
Tips and pitfalls
Difficulty identifying urethral orifice. Sometimes orifice is located in the glans penis. If just difficulty retracting foreskin, use plenty of gel.
No urine immediately.
The bladder has just been emptied; insert a 2mL syringe into the end of the catheter and aspirate any residual urine.
The catheter tip may be blocked with lidocaine gel; try gently instilling 15–20mL of sterile water and gently aspirating.
Still no urine. The patient may be anuric or a false passage may have been created; palpate to see if the bladder is empty or if you can feel the catheter balloon (which should not normally be palpable).
Treat anuria appropriately (see p. 112).
Consult a senior colleague if a false passage may have been created.
Inability to insert. Try a smaller catheter or a silastic (firmer). If unsuccessful, ask a senior for help; suprapubic catheterization may be needed (see p. 212).
Decompression of grossly distended bladder. Rapid decompression of a distended bladder (e.g. from chronic retention) may result in mucosal haemorrhage. Empty the bladder by 250–500mL every 30min until empty. Then monitor urine output closely as a brisk diuresis and dehydration may follow.
Bypassing catheter. Usually due to catheter blockage. Check urine output, flush the catheter, and observe. If urine is flowing down the catheter and bypassing it, the catheter may be too small; try a slightly larger size.
Catheter stops draining. The catheter may be kinked or blocked. Flush as above; if unsuccessful, try inserting a new catheter. Is the patient oliguric or anuric? Treat appropriately (see p. 64).
Female catheterization
In many hospitals, males are not allowed to catheterize awake females. Check before doing do and request a female chaperone.
Equipment
As for male catheterization.
Preparation
Lie patient on back with knees bent. Ask the patient to place heels together and allow knees to fall apart as far as possible.
Method
A similar technique is employed here to male catheterization, but note the following:
Separate the labia minora with the left hand and ensure the whole genital area is adequately cleaned using the right hand.
Identify the external urethral orifice. If this proves difficult in obese patients, an assistant may help by retracting the dependent fat from the pubic area.
Lubricate the tip of the catheter with sterile water or lidocaine gel and pass gently into the urethra.
Tips and pitfalls
Difficulty identifying urethral orifice. After warning the patient, place an index finger in the vagina to elevate the anterior vulva. Guide the catheter along the finger into the urethra.
Suprapubic catheterization
Indications
Urinary retention with failed or contraindicated urethral catheterization.
Cautions
Do not perform suprapubic catheterization on a patient with known bladder tumour or previous bladder surgery; seek expert advice.
Ensure by clinical examination (and if available, ultrasound bladder scanning) that the bladder is full and distended.
Equipment
Dressing pack.
Gloves.
Cleansing solution.
Two 10mL syringes.
25G and 21G needle.
10mL 1% lidocaine.
Prepacked suprapubic catheter set (usually containing catheter, trocar, and scalpel).
1/0 silk suture.
Catheter bag.
Preparation
Explain the procedure and consent the patient.
Lie patient supine and expose abdomen.
Confirm clinically an enlarged, tense bladder.
Identify catheterization site, 3–4cm (two finger breadths) above the symphysis pubis (see Fig. 4.7).
Site of typical suprapubic catheter insertion.
Method
Clean the skin thoroughly around the site and apply drapes.
Inject lignocaine into skin and subcutaneous tissues, injecting and aspirating in turn until urine is withdrawn.
Two systems for introducing a suprapubic catheter are available.
‘Nottingham’ introducer (uses trocar)
Make a 5mm incision at the identified site.
Advance the catheter, with trocar in place, through the incision and subcutaneous tissues. A ‘give’ will be felt as the bladder is entered.
Withdraw the trocar and ensure that there is free flow of urine from the catheter.
Inflate the catheter balloon and suture the flange of the catheter to the skin.
Attach a catheter bag.
Bonnano (modified Seldinger technique)
Make a 5mm nick in the skin.
Take the introducer needle and advance it, aspirating until urine is withdrawn.
Remove the syringe and pass the guidewire down the needle into the bladder, then remove the needle, holding the guidewire in place.
Pass the dilator firmly over the wire into the bladder.
Remove the dilator and pass the catheter into the bladder, securing it as above.
Tips and pitfalls
Bypassing urine. With some types of catheter and trocar, urine may initially bypass the catheter. This will cease with full advancement of the catheter and decompression of the bladder.
No urine or faeculent matter in catheter. Obtain help; you may have entered the peritoneum or bowel.
Paracentesis abdominis
Key facts
This is a useful technique in some patients for the diagnosis and management of ascites, often in a patient with malignancy.
Indications
Diagnostic evaluation of ascites.
Therapeutic drainage of ascites.
Equipment
Dressing pack.
Gloves.
Cleansing solution.
10mL syringe and 21G and 25G needles.
10mL 1% lidocaine.
60mL syringe with 16G aspiration needle for diagnostic ‘tap’.
Bonano catheter or paracentesis catheter, three-way tap, and collecting bag for therapeutic drainage.
Specimen container if appropriate.
Dressing.
Preparation
Explain the procedure and consent the patient.
Position the patient supine and expose the abdomen.
Percuss out and identify the position of ascites.
Identify a suitable tap site; the right lower quadrant is the commonest with the patient turned semilateral to ensure the ascites fills this area (see Fig. 4.8).
Target areas for ascitic tap at the level of the umbilicus, 3–4cm lateral to the mid-inguinal line.
Method
Prepare the skin at the appropriate site and place sterile drapes.
Infiltrate local anaesthetic into skin and subcutaneous tissues down to the peritoneum. Aspirate as the needle is advanced to avoid accidental vessel puncture.
Diagnostic tap
Introduce the aspiration needle through the skin and subcutaneous tissues while aspirating. A ‘give’ should be felt and fluid freely aspirated as the peritoneal cavity is entered.
Withdraw 15–20mL of fluid for a diagnostic evaluation.
Remove the aspiration needle carefully and apply an occlusive dressing.
Therapeutic drainage
Introduce catheter into abdominal wall until a ‘give’ is felt. Trial aspirate with a syringe to ensure ascites returned.
Slide catheter over the needle into the peritoneal cavity. Stop if resistance is encountered.
Allow up to 1000mL of ascites slowly over 1–2h.
Tips and pitfalls
Unable to aspirate adequate quantity of fluid. The ascites may be loculated. Drainage under ultrasound guidance may be helpful.
Blood or faeculent material. Continual staining of the ascitic fluid with fresh blood or any staining with faeculent material may indicate puncture of a vessel or viscus. This is potentially serious; inform a senior colleague.
Peritoneal catheter. Some patients who require repeated ascitic taps might benefit from placement of a temporary intraperitoneal catheter to allow daily drainage of ascites for symptomatic relief. There is a risk of peritonitis with these devices and only a short period of use is usually recommended, e.g. 2–3 days.
The volume of ascites drained should be closely monitored along with the patient's serum albumin and overall fluid balance. A maximum drainage of 2L/day is usually advised.
Rigid sigmoidoscopy
Key facts
This is a useful skill to learn. It is usually performed in the outpatient department as part of the investigation of lower GI complaints, but may have to be performed on the ward, e.g. acute admissions with rectal bleeding.
Indications
Investigation of anorectal symptoms.
Visualization of the rectum.
Equipment
Rigid sigmoidoscope with obturator and light source.
Lubricating jelly.
Gloves.
Gauze swabs.
Preparation
Explain the procedure and consent the patient.
Position the patient in the left lateral position with the hips flexed as fully as possible and knees partially extended.
Carry out a digital examination of the rectum to identify low-placed lesions or faecal loading, which may prevent safe insertion or obscure a useful view.
Method
Lubricate the sigmoidoscope with jelly.
With the obturator in place, introduce the scope gently through the anal sphincter in the direction of the umbilicus for approximately 5cm.
Remove the obturator; attach light source, insufflator, and eyepiece.
Introduce small amounts of air to open up the lumen.
Advance the instrument slowly under direct vision, ensuring that a patent lumen is identified prior to advancing the scope further.
Note the appearance of the mucosa and the presence of any mucosal lesions. The level of any lesion should also be noted using the marked scale on the outer casing of the sigmoidoscope.
If the patient experiences significant discomfort, do not persist.
Withdraw the scope slowly, again under direct vision.
Clean the area around the patient's anus.
Tips and pitfalls
Biopsy. Unless experienced in the skill, do not attempt biopsy of lesions. Note and document their position and inform a senior colleague.
Unable to see the upper rectum. Remember that the rectum has a sacral curvature, often pronounced in women; GENTLY use the tip of the scope as a ‘lever’ to push the anterior wall of the rectum forward to open to lumen. If this isn't easy and painless, don't persist; it may represent pathology.
Rectosigmoid junction. Negotiation of the rectosigmoid junction can be difficult. The best view that can be hoped for is to see the last sigmoid fold above the junction. Do not attempt to pass the scope into the distal sigmoid; this is the role of flexible sigmoidoscopy.
The rectum is said to start at the level of S2, but a distance of 15cm from the anorectal junction is used to define pathology which is termed ‘rectal’.
The rectum has two main angles.
The first is the acute anorectal angle which slopes posteriorly and is formed in part by the pull of the sling of levator ani.
The second is the sacral curvature which runs throughout the rectum, sloping progressively anteriorly up to the level of the rectosigmoid junction.
Three ‘lateral valves’ are commonly described, but are only the mucosal folds of the rectum equivalent to the colonic folds.
The peritoneal-lined ‘pouch of Douglas’ (or rectovesical pouch in males) extends a variable distance down the anterior wall of the rectum. Its contents (e.g. sigmoid colon) may be easily palpable, particularly in elderly females.
The upper third is covered by peritoneum anterolaterally, the middle third just anteriorly, and the lower third is entirely extraperitoneal.
The rectum has a complete outer longitudinal muscle coat (thus diverticular disease does not occur in the rectum).
The rectum and associated mesorectal fat, blood vessels, and lymph nodes are enclosed and separated from the ‘true’ pelvic organs by a fascial sheet—the mesorectum.
Local anaesthesia
Local anaesthesia is used in a variety of settings and is easy to deliver. It is essential to become familiar with the different agents, their relative merits, and potential dangers.
Indications
Minor procedures requiring anaesthesia, e.g. insertion of a chest drain, CV access, suprapubic catheterization, etc.
Excision of skin or subcutaneous lesions.
Infiltration of surgical wounds post-operatively.
Cautions
Allergy. Do not use local anaesthesia if there is a history of allergy to local anaesthetic.
Infection at site of infiltration. Injection may spread infection. The effect of the local anaesthetic will be diminished (due to an acidic environment) and injection may be more painful.
Increased risk of toxicity. Heart block, low cardiac output, epilepsy, myasthenia gravis, hepatic impairment, porphyria, β-blocker, or cimetidine therapy.
Epinephrine. Causes vasoconstriction, reducing bleeding locally and prolonging anaesthetic effect. It should not be used for injections into fingers, toes, ears, or penis (all supplied by end arteries) or where skin flaps are involved to reduce the chance of flap necrosis.
Agents
The two most commonly used agents are lidocaine and bupivacaine. Other agents, e.g. prilocaine, are less commonly used.
Lidocaine (previously known as lignocaine)
Used for local infiltration for minor procedures.
Concentrations. 0.5%, 1%, and 2%. Plain solutions (with no added adrenaline) or solutions containing adrenaline.
Duration of action. Rapid onset (2–3min), lasts 30–90min.
Maximum dose
Plain solutions. 3mg/kg, 20mL 1% or 10mL 2% for 70kg adult.
Solutions with adrenaline. 7mg/kg as systemic absorption is much slower, 50mL 1% or 25mL 2% for 70kg adult.
Bupivacaine
Useful in some prolonged procedures, wound infiltration, and regional blocks as it has a longer duration of action than lidocaine.
Concentrations. 0.25–0.75% plain solutions or with adrenaline.
Duration of action. Slower onset than lidocaine; effects last 3–8h.
Maximum dose. 3mg/kg for an adult, 2mg/kg for a child.
Equipment
Syringe.
Needles 21G–25G.
Alcohol swabs.
Preparation
Identify site of infiltration and check for any sign of infection or obvious subcutaneous blood vessels.
Calculate maximum dose of anaesthetic for each individual patient.
Draw up anaesthetic and check details of drug and dose.
Method
Clean area with alcohol swabs.
Inject anaesthetic slowly with a fine needle to area required, aspirating before each delivery to prevent accidental IV injection.
Injecting local anaesthetic in a fan-shaped area subcutaneously from a single injection is often more comfortable for the patient.
Field block. Injecting anaesthetic into the tissues surrounding the area which is to be anaesthetized (e.g. a cutaneous lesion) will often produce a field block, including the area itself.
Toxicity
This is caused by an overdose of local anaesthetic with systemic absorption or by accidental IV injection.
Symptoms and signs
Neurological. Drowsiness, confusion, slurred speech, light-headedness, tinnitus, numbness of tongue or mouth, convulsions, and coma.
Cardiovascular. Early tachycardia and hypertension, late bradycardia, hypotension, cardiac arrhythmias, and cardiac arrest may ensue.
These features usually will occur at a peak of 10–25min after subcutaneous injection, but occur immediately with IV injection.
Treatment
Stop procedure.
Maintain the patient's airway and provide oxygen.
Ensure IV access.
Perform an ECG.
Convulsions. Diazepam 5–10mg IV, slowly.
Hypotension. Raise end of bed and initiate IV fluids.
Bradycardia. Usually resolves, atropine is rarely needed.
Tips and pitfalls
You are more likely to achieve good anaesthetic block with a large volume of less concentrated local than a small volume of more concentrated local anaesthetic; generally use 1%, rather than 2%.
Allow 2–3min for the local to take effect; spend this time setting up your instruments and draping the patient.
Accidental IV injection. See toxicity section above.
Inadequate analgesia. Infiltrate more anaesthetic up to the patient's maximum calculated dose. If the patient is still not tolerating the procedure, alternative anaesthetic methods may have to be considered, e.g. regional anaesthesia (note maximum local anaesthetic dose), sedation, or general anaesthetic.
The smaller the needle and the more slowly you inject initially, the less painful it is for the patient.
Intercostal nerve block
This may be a useful skill to learn, although it is usually performed by anaesthetists.
Indications
Pain due to fractured ribs.
Post-thoracotomy pain relief.
Equipment
Dressing pack.
Skin antiseptic.
Gloves.
20mL syringe and needle.
20mL of local anaesthetic, e.g. bupivacaine.
Preparation
The patient is positioned as for pleural aspiration (see ‘Pleural aspiration’, p. 635) and the site of infiltration is identified.
Broken ribs. Medial to the site of fracture on the posterior aspect of the chest wall.
Post-thoracotomy. Medial to the posterior edge of the scar on the posterior chest wall.
Method
Ensure that the skin is prepared thoroughly with antiseptic. Drapes are placed appropriately.
Insert the needle and syringe containing anaesthetic through the skin, inferior to the rib (unlike pleural aspiration) associated with the nerve to be blocked.
Aspirate the syringe to ensure that the needle has not entered a blood vessel or the pleural space. If no blood or air is withdrawn, the site is infiltrated with 4–5mL of anaesthetic.
This is repeated at various sites.
Obtain a CXR to ensure a pneumothorax has not complicated the procedure.
Note
Multiple blocks. Ensure that the patient does not receive a toxic dose of local anaesthetic.
Air or blood is aspirated. Withdraw the needle slowly, get a CXR.
Local anaesthetic works by blocking Na channels in the nerve membrane, preventing propagation of the action potential. Small, non-myelinated pain fibres are blocked first. Large, myelinated fibres that conduct impulses from pressure senses are the last to be blocked.
