Endotracheal intubation and complications

Endotracheal intubation

1. 11
Endotracheal intubationEndotracheal intubation
Indications Indications
An artificial airway is necessary in the following An artificial airway is necessary in the following
circumstances :circumstances :

Apnoea – The provision of mechanical ventilation, e.g. Apnoea – The provision of mechanical ventilation, e.g.
unconsciousness, severe respiratory muscle weakness, self-unconsciousness, severe respiratory muscle weakness, self-
poisoning.poisoning.

Respiratory failure – The provision of mechanical ventilation, Respiratory failure – The provision of mechanical ventilation,
e.g. ARDS, peumoniae.g. ARDS, peumonia1111

Airway protection – Unconciousness, trauma, aspiration risk, Airway protection – Unconciousness, trauma, aspiration risk,
poisoning poisoning

Airway obstruction – To maintain airway patency, e.g. trauma, Airway obstruction – To maintain airway patency, e.g. trauma,
laryngeal oedema, tumour, burns laryngeal oedema, tumour, burns

Haemodynamic instability – To facilitate mechanical ventilation, Haemodynamic instability – To facilitate mechanical ventilation,
e.g. shock, cardiac arrest.e.g. shock, cardiac arrest.

2. 22
Choice of endotracheal tube Choice of endotracheal tube

Most adults require a standard high volume, low Most adults require a standard high volume, low
pressure cuffed endotracheal tube. pressure cuffed endotracheal tube.

The averge sized adult will require a size 9.0mm id The averge sized adult will require a size 9.0mm id
tube (size 8.0mm id for females) cut to length of 23cm tube (size 8.0mm id for females) cut to length of 23cm
(21cm for females). (21cm for females).

Obviously, different size patients may require changes Obviously, different size patients may require changes
to these sizes and particular problems with the upper to these sizes and particular problems with the upper
airway, e.g. trauma, oedema, may require a smaller airway, e.g. trauma, oedema, may require a smaller
tube.tube.

In specific situations non-standard tubes may be In specific situations non-standard tubes may be
used, e.g. jet ventilation, armoured tubes (where head used, e.g. jet ventilation, armoured tubes (where head
mobility is expected or for patients who are to be mobility is expected or for patients who are to be
positioned prone), double lumen tubes to isolate the positioned prone), double lumen tubes to isolate the
right or left lung. right or left lung.

3. 33
Route of intubation Route of intubation

The usual routes of intubation are oro-tracheal and The usual routes of intubation are oro-tracheal and
naso-tracheal. naso-tracheal.

Oro-tracheal intubation in preferred.Oro-tracheal intubation in preferred.

The naso-tracheal route has the advantages of The naso-tracheal route has the advantages of
increased pateint comfort and the possibility of increased pateint comfort and the possibility of
easier blind placement; it is also easier to secure the easier blind placement; it is also easier to secure the
tube. tube.

However, there are several disadvantages. However, there are several disadvantages.

The tube is usually smaller, there is a risk of sinusitis The tube is usually smaller, there is a risk of sinusitis
and otitis media and the route is contrandicated in and otitis media and the route is contrandicated in
coagulopathy, CSF leak and nasal fractures.coagulopathy, CSF leak and nasal fractures.

4. 44
Difficult intubation Difficult intubation

If a difficult intubation is predicted is should not be If a difficult intubation is predicted is should not be
attempted by an inexperienced operator. attempted by an inexperienced operator.
Difficulty may be predicted in the patient with a small Difficulty may be predicted in the patient with a small
mouth, high arched palate, large upper incisors, mouth, high arched palate, large upper incisors,
hypognathia, large tongue, anterior larynx, short neck, hypognathia, large tongue, anterior larynx, short neck,
immobile temporomandibular joints, immobile immobile temporomandibular joints, immobile
cervical joints or morbid obesity. cervical joints or morbid obesity.

If a difficult intubation present unexpectedly the use If a difficult intubation present unexpectedly the use
of a stylet, a straight bladed laryngoscope or a of a stylet, a straight bladed laryngoscope or a
fibreoptic laryngoscope may help. fibreoptic laryngoscope may help.
It is important not to persist for too long; revert to bag It is important not to persist for too long; revert to bag
and mask ventilation to ensure adequate oxygenation. and mask ventilation to ensure adequate oxygenation.

5. 55
Complications of intubation Complications of intubation
Early complications Early complications
Trauma, e.g. haemorrhage, mediastinal perforation Trauma, e.g. haemorrhage, mediastinal perforation
Haemodynamic collapse, e.g. positive pressure Haemodynamic collapse, e.g. positive pressure
ventilation, vasodilation, arrhythmias or rapid ventilation, vasodilation, arrhythmias or rapid
correction of hypercapnia.correction of hypercapnia.
Tube malposition, e.g. failed or endobronchial Tube malposition, e.g. failed or endobronchial
intubation. intubation.
Later complications Later complications
Infection including maxillary sinusitis if nasally Infection including maxillary sinusitis if nasally
intubated intubated
Cuff pressure trauma (maintain cuff pressure Cuff pressure trauma (maintain cuff pressure
<25cmH2O)<25cmH2O)
Mouth /Lip traumaMouth /Lip trauma

6. 66
Equipment required Equipment required

Suction (Yankauer tip)Suction (Yankauer tip)

Oxyen, rebreathing bag and maskOxyen, rebreathing bag and mask

Laryngoscope (two curved blades and straight blade)Laryngoscope (two curved blades and straight blade)

Stylet / bougieStylet / bougie

Endotracheal tubes (preferred size and smaller)Endotracheal tubes (preferred size and smaller)

Magill forcepsMagill forceps

Drugs (Induction agent, muscle relaxant, sedative, Drugs (Induction agent, muscle relaxant, sedative,
anticholinergic)anticholinergic)

Syringe for cuff inflationSyringe for cuff inflation

Tape to secure tubeTape to secure tube

7. 77
TracheostomyTracheostomy
Indications Indications

To provide an artificial airway where oro-or naso-To provide an artificial airway where oro-or naso-
tracheal intubation is to be avoided. tracheal intubation is to be avoided.

This may be to provide better patient comfort, to This may be to provide better patient comfort, to
avoid mouth or nasal trauma or, in an emergency, avoid mouth or nasal trauma or, in an emergency,
where there is acute upper airway obstruction. where there is acute upper airway obstruction.

Converting an oro-or naso-tracheal tube to a Converting an oro-or naso-tracheal tube to a
tracheostomy should be considered early in cases of tracheostomy should be considered early in cases of
difficult intubation to avoid the risks of repeat difficult intubation to avoid the risks of repeat
intubation, or later in caes of prolonged intubation to intubation, or later in caes of prolonged intubation to
avoid laryngela trauma. avoid laryngela trauma.

8. 88

The exact time that one should consider performing The exact time that one should consider performing
a tracheostomy in caes of prolonged intubation is not a tracheostomy in caes of prolonged intubation is not
known although current practice is at about 10-known although current practice is at about 10-
16days. 16days.

High volume, low pressure cuffs on modern High volume, low pressure cuffs on modern
endoracheal tubes do not cause more tracheal endoracheal tubes do not cause more tracheal
damage than the equivalent cuffs of a tracheostomy damage than the equivalent cuffs of a tracheostomy
tube, but avoiding the risks of laryngeal and vocal tube, but avoiding the risks of laryngeal and vocal
cord damage may provide some advantage for cord damage may provide some advantage for
tracheostomy. tracheostomy.

The reduced need for sedation is a definite The reduced need for sedation is a definite
advantage. advantage.

9. 99
Percutaneous tracheostomyPercutaneous tracheostomy
A more rapid procedure with less tissue trauma and scarring than A more rapid procedure with less tissue trauma and scarring than
the standard open surgical technique. the standard open surgical technique.
Can be performed in the intensive care unit avoiding the need to Can be performed in the intensive care unit avoiding the need to
transfer patients to theatre. transfer patients to theatre.
The technique involves infiltration of the subcutaneous tissues with The technique involves infiltration of the subcutaneous tissues with
lignocaine and adrenaline. lignocaine and adrenaline.
A1-1.5cm skin crease incision is made in the midline. Subcutaneous A1-1.5cm skin crease incision is made in the midline. Subcutaneous
tissue is blunt dissected to the anterior tracheal wall. tissue is blunt dissected to the anterior tracheal wall.
The trachea is punctured with a 14G needle between the 1The trachea is punctured with a 14G needle between the 1
stst
and 2 and 2
ndnd

tracheal cartilages and a guide wire is inserted into the trachea. tracheal cartilages and a guide wire is inserted into the trachea.
The stoma is created either by progressive dilation to 36Fr (Ciaglia The stoma is created either by progressive dilation to 36Fr (Ciaglia
technique) or by use of single stage guided dilating tool (Schachner-technique) or by use of single stage guided dilating tool (Schachner-
Ovill technique). Ovill technique).
In the former case the tracheostomy tube is introduced over an In the former case the tracheostomy tube is introduced over an
appropriate size dilator and in the latter through the open dilating appropriate size dilator and in the latter through the open dilating
tool. tool.

10. 1010
ComplicationsComplications

The main early complication is haemorrhage, either from trauma The main early complication is haemorrhage, either from trauma
to the thyroid isthmus or aberrant superior thyroid vessels. to the thyroid isthmus or aberrant superior thyroid vessels.
Although most early haemorrhage is easily controlled, Although most early haemorrhage is easily controlled,
coagulation disorder in critically ill patients may created additional coagulation disorder in critically ill patients may created additional
problems.problems.

Tracheal stenos is is related to creation of the tracheal stoma and Tracheal stenos is is related to creation of the tracheal stoma and
subsequent low grade infection.subsequent low grade infection.

This is thought to be a greater problem with open surgical This is thought to be a greater problem with open surgical
tracheostomies than percutaneous tracheostomies. tracheostomies than percutaneous tracheostomies.

The presence of a foreign body in the trachea, bypassing the The presence of a foreign body in the trachea, bypassing the
normal upper airway defence mechanisms, together with an open normal upper airway defence mechanisms, together with an open
neck wound, presents an obvious infection risk. neck wound, presents an obvious infection risk.

Subglottic infection is more likely after trans-laryngeal intubation. Subglottic infection is more likely after trans-laryngeal intubation.
Tracheo-oesophageal fistula is a rare complication due to trauma Tracheo-oesophageal fistula is a rare complication due to trauma
or pressure necrosis of the posterior wall of the trachea. or pressure necrosis of the posterior wall of the trachea.

11. 1111
Maintenance of a tracheostomyMaintenance of a tracheostomy

Since the upper air passages have been bypassed Since the upper air passages have been bypassed
artificial humidification is required. artificial humidification is required.

Cough is less effective without a functioninglarynx so Cough is less effective without a functioninglarynx so
regular tracheal suction will be necessary.regular tracheal suction will be necessary.

Furthermore, the larynx provides a small amount of Furthermore, the larynx provides a small amount of
natural PEEP which is lost with a tracheostomy. natural PEEP which is lost with a tracheostomy.

The risk of basal atelectasis can be overcome with The risk of basal atelectasis can be overcome with
CPAP or attention to respiratory exercises which CPAP or attention to respiratory exercises which
promote deep breathing. promote deep breathing.

A safe fistula forms within 3 days allowing A safe fistula forms within 3 days allowing
replacement of the tracheostomy tube. replacement of the tracheostomy tube.

12. 1212
Tracheostomy tubesTracheostomy tubes
Standard high volume, low pressure cuffStandard high volume, low pressure cuff
Fenestrated with or without cuffFenestrated with or without cuff

Useful where airway protection is not a primary Useful where airway protection is not a primary
concern. concern.

May be closed during normal breathing while May be closed during normal breathing while
providing intermittent suction access.providing intermittent suction access.
Fenestrated with inner tubeFenestrated with inner tube

As above but with an inner tube to facilitate closure As above but with an inner tube to facilitate closure
of the fenestration during intermittent mechanical of the fenestration during intermittent mechanical
ventilation. ventilation.

13. 1313
Fenestrated with speaking valveFenestrated with speaking valve
Inspiration allowed through the tracheostomy to reduce dead Inspiration allowed through the tracheostomy to reduce dead
space and inspiratory resistance. space and inspiratory resistance.

Expiration through the larynx, via the fenestration, allowing Expiration through the larynx, via the fenestration, allowing
speech and the advantages of laryngeal PEEP.speech and the advantages of laryngeal PEEP.
Adjustable flangeAdjustable flange
Accommodates extreme variations in skin to trachea depth Accommodates extreme variations in skin to trachea depth
while ensuring the cuff remains central in the trachea.while ensuring the cuff remains central in the trachea.
Pitt speaking tube Pitt speaking tube

A non fenestrated, cuffed tube for continuous mechanical A non fenestrated, cuffed tube for continuous mechanical
ventilation and airway protection with a port to direct airflow ventilation and airway protection with a port to direct airflow
above the cuff to the larynx. above the cuff to the larynx.

When airflow is direct through the larynx some patients are able When airflow is direct through the larynx some patients are able
to vocalise.to vocalise.
Sliver tubeSliver tube
An uncuffed tube which is used occasionally in ENT practice to An uncuffed tube which is used occasionally in ENT practice to
maintain a tracheostomy fistula.maintain a tracheostomy fistula.

14. 1414
Defibrillation Defibrillation
Electrical conversion of a tachyarrhythmia to restore Electrical conversion of a tachyarrhythmia to restore
normal sinus rhythm. normal sinus rhythm.
This may be an emergency procedure (when the This may be an emergency procedure (when the
circulation is absent or severely comporomised), semi circulation is absent or severely comporomised), semi
elective (when the circulation is compromised to a elective (when the circulation is compromised to a
lasser degree), or elective (when synchronised lasser degree), or elective (when synchronised
cardioversion is performed to restore sinus rhythm cardioversion is performed to restore sinus rhythm
for a non-compromisingsupra-ventricular for a non-compromisingsupra-ventricular
tachycardia).tachycardia).
Synchronisation requires initial connection of ECG Synchronisation requires initial connection of ECG
leads from the patient to the defibrillator so that the leads from the patient to the defibrillator so that the
shock is delivered on the R wave to minimize the risk shock is delivered on the R wave to minimize the risk
of ventricular fibrillation. of ventricular fibrillation.

15. 1515
Indications Indications
Compromised circulation, e.g. VF, VTCompromised circulation, e.g. VF, VT
Restoration of sinus rhythm and more effective Restoration of sinus rhythm and more effective
cardiac outputcardiac output

Lessens risk of cardiac thrombus formation Lessens risk of cardiac thrombus formation
Contraindications / cautionsContraindications / cautions
Aware patientAware patient
Severe coagulopathySevere coagulopathy
Caution with recent thrombolysisCaution with recent thrombolysis
Digoxin levels in toxic rangeDigoxin levels in toxic range
ComplicationsComplications
Surface burnSurface burn
Pericardial tamponadePericardial tamponade
Electrocution of bystandersElectrocution of bystanders

16. 1616
TechniqueTechnique
The chances of maintaining sinus rhythm are The chances of maintaining sinus rhythm are
increased in elective cardioversion if Kincreased in elective cardioversion if K
++
>4.5mmol/L >4.5mmol/L
and plasma Mgand plasma Mg
2+2+
levels are normal. levels are normal.
Prior to defibrillation, ensure self and onlookers are Prior to defibrillation, ensure self and onlookers are
not in contact with patient or bed frame.not in contact with patient or bed frame.

To reduce the risk of superficial burns, replace To reduce the risk of superficial burns, replace
gel/gelled pads after every 3 shocks.gel/gelled pads after every 3 shocks.
Consider resisting paddle position (e.g. antero-Consider resisting paddle position (e.g. antero-
posterior) if defibrillation fails.posterior) if defibrillation fails.
The risk of intractable VF following defibrillation in a The risk of intractable VF following defibrillation in a
patient receiving digoxin is small unless the plasma patient receiving digoxin is small unless the plasma
digoxin levels are in the toxic range or the patient is digoxin levels are in the toxic range or the patient is
hypovolaemic.hypovolaemic.

17. 1717
Temporary internal pacing Temporary internal pacing

When the heart’s intrinsic pacemaking ability fails, When the heart’s intrinsic pacemaking ability fails,
temporary internal pacing can be instituted. temporary internal pacing can be instituted.

Electrodes can be endocardial (inserted via a cental Electrodes can be endocardial (inserted via a cental
vein) or epicardial (placed on the external surface of vein) or epicardial (placed on the external surface of
the heart at thoracotomy). the heart at thoracotomy).

The endocardial wire may be placed under The endocardial wire may be placed under
fluoroscopic control or ‘blind’ using a balloon fluoroscopic control or ‘blind’ using a balloon
flotation catheter. flotation catheter.

18. 1818
IndicationsIndications
Third degree heart block Third degree heart block
Mobitz Type II second – degree heart block when the Mobitz Type II second – degree heart block when the
circulation is compromised or an operation is plannedcirculation is compromised or an operation is planned

Overpacing (rarely)Overpacing (rarely)
Asystole (although external pacing is more useful Asystole (although external pacing is more useful
initially)initially)
ComplicationsComplications

As for central venous catheter insertion As for central venous catheter insertion
ArrhythmiasArrhythmias
Infection (including endocarditis)Infection (including endocarditis)

Myocardial perforation (rare)Myocardial perforation (rare)
Contraindications/cautionsContraindications/cautions
As for central venous catheter insertion As for central venous catheter insertion

19. 1919
TroubleshootingTroubleshooting
Failure to pace may be due to :Failure to pace may be due to :

No pacemaker output (no spikes seen) – check No pacemaker output (no spikes seen) – check
connections, battery connections, battery

No capture (pacing spikes seen but no QRS complex No capture (pacing spikes seen but no QRS complex
following) – poor positioning/dislodgement of wire. following) – poor positioning/dislodgement of wire.

Temporarily increase output as this may regain Temporarily increase output as this may regain
capture. Reposition / replace wire.capture. Reposition / replace wire.

20. 2020
GeneralGeneral
1.1.Check threshold daily as it will rise slowly over 48-96h, Check threshold daily as it will rise slowly over 48-96h,
probably due to fibrosis occurring around the electrodes.probably due to fibrosis occurring around the electrodes.
2.2.Overpacing is occasionally indicated for a tachycardia not Overpacing is occasionally indicated for a tachycardia not
responding to antiarrhythmic therapy or cardioversion. For responding to antiarrhythmic therapy or cardioversion. For
SVT, pacing is usually attempted with the wire sited in the SVT, pacing is usually attempted with the wire sited in the
right atrium. Pace at rate 20-30bpm above patient’s heart right atrium. Pace at rate 20-30bpm above patient’s heart
rate for 10-15sec then either decrease rate immediately to rate for 10-15sec then either decrease rate immediately to
80 bpm or slowly, by 20 bpm every 5-10sec.80 bpm or slowly, by 20 bpm every 5-10sec.
3.3.If overpacing fails, underpacing may be attempted with the If overpacing fails, underpacing may be attempted with the
wire situated in either atrium (for SVT) or, usually, ventricle wire situated in either atrium (for SVT) or, usually, ventricle
(for either SVT or VT). A paced rate of 80-100 bpm may (for either SVT or VT). A paced rate of 80-100 bpm may
produce a refractory period sufficient to suppress the produce a refractory period sufficient to suppress the
intrinsic tachycardia.intrinsic tachycardia.
4.4.Epicardial pacing performed during cardiac surgery requires Epicardial pacing performed during cardiac surgery requires
sitting of either two epicardial electrodes or one epicardial sitting of either two epicardial electrodes or one epicardial
and one skin electrode (usually a hypodermic needle). The and one skin electrode (usually a hypodermic needle). The
pacing threshold of epicardial wires rises quickly and may pacing threshold of epicardial wires rises quickly and may
become ineffective after 1-2 days.become ineffective after 1-2 days.

21. 2121
Technique (for endocardial electrode Technique (for endocardial electrode
placement)placement)
1.1.If using fluoroscopy, move patient to X-ray suite or If using fluoroscopy, move patient to X-ray suite or
place lead shields around bed area. Place patient place lead shields around bed area. Place patient
on screening table. Staff should wear lead aprons.on screening table. Staff should wear lead aprons.
2.2.Use aseptic technique throughout. Insert 6Fr Use aseptic technique throughout. Insert 6Fr
sheath in internal jugular or subclavian vein. Suture sheath in internal jugular or subclavian vein. Suture
in position.in position.
3.3.Connect pacing wire electrodes to pacing box (black Connect pacing wire electrodes to pacing box (black
= negative polarity = distal, red = positive polarity = = negative polarity = distal, red = positive polarity =
proximal). Set pace maker to demand. Check box is proximal). Set pace maker to demand. Check box is
working and battery charge adequate. Turn pacing working and battery charge adequate. Turn pacing
rate to > 30 bpm above patient’s intrinsic rhythm. rate to > 30 bpm above patient’s intrinsic rhythm.
Set voltage 4V.Set voltage 4V.

22. 2222
4.4.Insert pacing wire through sheath into central vein. Insert pacing wire through sheath into central vein.
If using balloon catheter, insert to 15-20cm depth If using balloon catheter, insert to 15-20cm depth
then inflate ballon. Advance catheter, viewing ECG then inflate ballon. Advance catheter, viewing ECG
monitor for change in ECG morphology and capture monitor for change in ECG morphology and capture
of pacing rate. If using screening direct wire toward of pacing rate. If using screening direct wire toward
the apex of the right ventricle. Approximate the apex of the right ventricle. Approximate
insertion depth from a neck vein is 35-40 cm.insertion depth from a neck vein is 35-40 cm.
5.5.If pacing impulses not captured, (deflate balloon), If pacing impulses not captured, (deflate balloon),
withdraw wire to 15 cm insertion depth then repeat withdraw wire to 15 cm insertion depth then repeat
step 4.step 4.
6.6.Once pacing captured, decrease voltage by Once pacing captured, decrease voltage by
decrements to determine threshold at which pacing decrements to determine threshold at which pacing
is no longer captured. Ideal position determined by is no longer captured. Ideal position determined by
a threshold <0.4V. If not achieved, re-position wire. a threshold <0.4V. If not achieved, re-position wire.
7.7.If possible, ask patient to cough to check that the If possible, ask patient to cough to check that the
wire does not dislodge.wire does not dislodge.
8.8.Set voltage at 3X threshold and set desired heart Set voltage at 3X threshold and set desired heart
rate on demand mode. Tape wire securely to patient rate on demand mode. Tape wire securely to patient
prevent dislodgement.prevent dislodgement.

23. 2323
External pacingExternal pacing
External pacing can be rapidly performed by External pacing can be rapidly performed by
placement of two electrodes on the fron and rear placement of two electrodes on the fron and rear
chest wall when asystole or third degree heart block chest wall when asystole or third degree heart block
has produced acute haemodynamic compromise.has produced acute haemodynamic compromise.
It is often used as a bridge to temporary internal It is often used as a bridge to temporary internal
pacing. It can also be used as a prophylactic measure pacing. It can also be used as a prophylactic measure
e.g. for Mobitz Type II second degree heart block.e.g. for Mobitz Type II second degree heart block.
Indications Indications
Asystole (in conjunction with cardiopulmonary Asystole (in conjunction with cardiopulmonary
resuscitation)resuscitation)
Third degree heart blockThird degree heart block
Prophylactic Prophylactic
Complications Complications
Discomfort Discomfort

24. 2424
Technique Technique
1.1.Connect pacing wire gelled electrodes to pacemaker. Place black Connect pacing wire gelled electrodes to pacemaker. Place black
(=negative polarity) electrode on the anterior chest wall to the left (=negative polarity) electrode on the anterior chest wall to the left
of the lower sternum and ed (= positive polarity) electrode to the of the lower sternum and ed (= positive polarity) electrode to the
corresponding position on the posterior hemithorax.corresponding position on the posterior hemithorax.
2.2.Connect ECG electrodes from ECG monitor to external pacemaker Connect ECG electrodes from ECG monitor to external pacemaker
and another set of electrodes from pacemaker to patient. and another set of electrodes from pacemaker to patient.
3.3.Set pacemaker to demand. Turn pacing rate to >30 bpm above Set pacemaker to demand. Turn pacing rate to >30 bpm above
patient’s intrinsic rhythm. Set current to 70mA.patient’s intrinsic rhythm. Set current to 70mA.
4.4.Start pacing. Increase current (by 5mA increments) until pacing Start pacing. Increase current (by 5mA increments) until pacing
rate captured on monitor.rate captured on monitor.
5.5.If pacing rate not captured at current of 120-130mA, re-site If pacing rate not captured at current of 120-130mA, re-site
electrodes and repeat steps 3-4.electrodes and repeat steps 3-4.
6.6.Once pacing captured, set current at 5-10mA above threshold.Once pacing captured, set current at 5-10mA above threshold.
GeneralGeneral

In asystole, even though an electrical rhythm is produced by the In asystole, even though an electrical rhythm is produced by the
external pacing, this does not guarantee an adequate output is external pacing, this does not guarantee an adequate output is
being generated.being generated.

Although the patient may complain of discomfort, external chest Although the patient may complain of discomfort, external chest
wall pacing is better tolerated and more reliable than other forms wall pacing is better tolerated and more reliable than other forms
or external pacing e.g. oesophageal.or external pacing e.g. oesophageal.