ett intubation

8/2/2019 ETT intubation

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Endotracheal intubation

Indications

An artificial airway is necessary in the followingcircumstances :

Apnoea The provision of mechanical ventilation, e.g.unconsciousness, severe respiratory muscle weakness, self-

poisoning. Respiratory failure The provision of mechanical ventilation, e.g.

ARDS, peumonia11

Airway protection Unconciousness, trauma, aspiration risk,poisoning

Airway obstruction To maintain airway patency, e.g. trauma,laryngeal oedema, tumour, burns

Haemodynamic instability To facilitate mechanical ventilation, e.g.shock, cardiac arrest.


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Choice of endotracheal tube

Most adults require a standard high volume, lowpressure cuffed endotracheal tube.

The averge sized adult will require a size 9.0mm id tube(size 8.0mm id for females) cut to length of 23cm (21cmfor females).

Obviously, different size patients may require changes tothese sizes and particular problems with the upperairway, e.g. trauma, oedema, may require a smallertube.

In specific situations non-standard tubes may be used,e.g. jet ventilation, armoured tubes (where head mobilityis expected or for patients who are to be position

edprone), double lumen tubes to isolate the right or left

lung.


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Route of intubation

The usual routes of intubation are oro-tracheal andnaso-tracheal.

Oro-tracheal intubation in preferred.

The naso-tracheal route has the advantages of increasedpateint comfort and the possibility of easier blindplacement; it is also easier to secure the tube.

However, there are several disadvantages.

The tube is usually smaller, there is a risk of sinusitis andotitis media and the route is contrandicated incoagulopathy, CSF leak and nasal fractures.


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Difficult intubation

If a difficult intubation is predicted is should not beattempted by an inexperienced operator.

Difficulty may be predicted in the patient with a smallmouth, high arched palate, large upper incisors,

hypognathia, large tongue, anterior larynx, short neck,immobile temporomandibular joints, immobile cervicaljoints or morbid obesity.

If a difficult intubation present unexpectedly the use of astylet, a straight bladed laryngoscope or a fibreopticlaryngoscope may help.

It is important not to persist for too long; revert to bagand mask ventilation to ensure adequate oxygenation.


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Complications of intubation

Early complications

Trauma, e.g. haemorrhage, mediastinal perforation

Haemodynamic collapse, e.g. positive pressureventilation, vasodilation, arrhythmias or rapid correction

of hypercapnia. Tube malposition, e.g. failed or endobronchial

intubation.

Later complications

Infection including maxillary sinusitis if nasally intubated Cuff pressure trauma (maintain cuff pressure


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Equipment required

Suction (Yankauer tip)

Oxyen, rebreathing bag and mask

Laryngoscope (two curved blades and straight blade)

Stylet / bougie Endotracheal tubes (preferred size and smaller)

Magill forceps

Drugs (Induction agent, muscle relaxant, sedative,

anticholinergic) Syringe for cuff inflation

Tape to secure tube


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Tracheostomy

Indications

To provide an artificial airway where oro-or naso-tracheal intubation is to be avoided.

This may be to provide better patient comfort, to avoidmouth or nasal trauma or, in an emergency, where thereis acute upper airway obstruction.

Converting an oro-or naso-tracheal tube to atracheostomy should be considered early in cases ofdifficult intubation to avoid the risks of repeat intubation,or later in caes of prolonged intubation to avoidlaryngela trauma.


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The exact time that one should consider performing atracheostomy in caes of prolonged intubation is notknown although current practice is at about 10-16days.

High volume, low pressure cuffs on modern endorachealtubes do not cause more tracheal damage than theequivalent cuffs of a tracheostomy tube, but avoidingthe risks of laryngeal and vocal cord damage mayprovide some advantage for tracheostomy.

The reduced need for sedation is a definite advantage.


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Percutaneous tracheostomy

A more rapid procedure with less tissue trauma and scarring than

the standard open surgical technique. Can be performed in the intensive care unit avoiding the need to

transfer patients to theatre.

The technique involves infiltration of the subcutaneous tissues withlignocaine and adrenaline.

A1-1.5cm skin crease incision is made in the midline. Subcutaneoustissue is blunt dissected to the anterior tracheal wall.

The trachea is punctured with a 14G needle between the 1st and 2ndtracheal cartilages and a guide wire is inserted into the trachea.

The stoma is created either by progressive dilation to 36Fr (Ciagliatechnique) or by use of single stage guided dilating tool (Schachner-Ovill technique).

In the former case the tracheostomy tube is introduced over anappropriate size dilator and in the latter through the open dilatingtool.


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Complications

The main early complication is haemorrhage, either from trauma tothe thyroid isthmus or aberrant superior thyroid vessels.

Although most early haemorrhage is easily controlled, coagulationdisorder in critically ill patients may created additional problems.

Tracheal stenos is is related to creation of the tracheal stoma and

subsequent low grade infection. This is thought to be a greater problem with open surgical

tracheostomies than percutaneous tracheostomies.

The presence of a foreign body in the trachea, bypassing the normalupper airway defence mechanisms, together with an open neck

wound, presents an obvious infection risk. Subglottic infection is more likely after trans-laryngeal intubation.

Tracheo-oesophageal fistula is a rare complication due to trauma orpressure necrosis of the posterior wall of the trachea.


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Maintenance of a tracheostomy

Since the upper air passages have been bypassedartificial humidification is required.

Cough is less effective without a functioninglarynx soregular tracheal suction will be necessary.

Furthermore, the larynx provides a small amount ofnatural PEEP which is lost with a tracheostomy.

The risk of basal atelectasis can be overcome with CPAPor attention to respiratory exercises which promote deepbreathing.

A safe fistula forms within 3 days allowing replacementof the tracheostomy tube.


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Tracheostomy tubes

Standard high volume, low pressure cuff

Fenestrated with or without cuff

Useful where airway protection is not a primary concern.

May be closed during normal breathing while providingintermittent suction access.

Fenestrated with inner tube

As above but with an inner tube to facilitate closure of

the fenestration during intermittent mechanicalventilation.


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Fenestrated with speaking valve

Inspiration allowed through the tracheostomy to reduce dead spaceand inspiratory resistance.

Expiration through the larynx, via the fenestration, allowing speechand the advantages of laryngeal PEEP.

Adjustable flange

Accommodates extreme variations in skin to trachea depth whileensuring the cuff remains central in the trachea.

Pitt speaking tube

A non fenestrated, cuffed tube for continuous mechanical ventilationand airway protection with a port to direct airflow above the cuff tothe larynx.

When airflow is direct through the larynx some patients are able tovocalise.

Sliver tube An uncuffed tube which is used occasionally in ENT practice to

maintain a tracheostomy fistula.


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Defibrillation

Electrical conversion of a tachyarrhythmia to restorenormal sinus rhythm.

This may be an emergency procedure (when thecirculation is absent or severely comporomised), semi

elective (when the circulation is compromised to a lasserdegree), or elective (when synchronised cardioversion isperformed to restore sinus rhythm for a non-compromisingsupra-ventricular tachycardia).

Synchronisation requires initial connection of ECG leads

from the patient to the defibrillator so that the shock isdelivered on the R wave to minimize the risk ofventricular fibrillation.


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Indications

Compromised circulation, e.g. VF, VT

Restoration of sinus rhythm and more effective cardiacoutput

Lessens risk of cardiac thrombus formation

Contraindications / cautions

Aware patient

Severe coagulopathy

Caution with recent thrombolysis

Digoxin levels in toxic range

Complications

Surface burn

Pericardial tamponade

Electrocution of bystanders


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Technique

The chances of maintaining sinus rhythm are increasedin elective cardioversion if K+>4.5mmol/L and plasmaMg2+ levels are normal.

Prior to defibrillation, ensure self and onlookers are notin contact with patient or bed frame.

To reduce the risk of superficial burns, replace gel/gelledpads after every 3 shocks.

Consider resisting paddle position (e.g. antero-posterior)if defibrillation fails.

The risk of intractable VF following defibrillation in apatient receiving digoxin is small unless the plasmadigoxin levels are in the toxic range or the patient ishypovolaemic.


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Temporary internal pacing

When the hearts intrinsic pacemaking ability fails,temporary internal pacing can be instituted.

Electrodes can be endocardial (inserted via a cental vein)or epicardial (placed on the external surface of the heartat thoracotomy).

The endocardial wire may be placed under fluoroscopiccontrol or blindusing a balloon flotation catheter.


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Indications

Third degree heart block

Mobitz Type II second

degree heart block when thecirculation is compromised or an operation is planned

Overpacing (rarely)

Asystole (although external pacing is more usefulinitially)

Complications As for central venous catheter insertion

Arrhythmias

Infection (including endocarditis)

Myocardial perforation (rare)Contraindications/cautions

As for central venous catheter insertion


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Troubleshooting

Failure to pace may be due to :

No pacemaker output (no spikes seen) checkconnections, battery

No capture (pacing spikes seen but no QRS complexfollowing) poor positioning/dislodgement of wire.

Temporarily increase output as this may regain capture.Reposition / replace wire.


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General

1. Check threshold daily as it will rise slowly over 48-96h,

probably due to fibrosis occurring around the electrodes.2. Overpacing is occasionally indicated for a tachycardia not

responding to antiarrhythmic therapy or cardioversion. ForSVT, pacing is usually attempted with the wire sited in theright atrium. Pace at rate 20-30bpm above patients heartrate for 10-15sec then either decrease rate immediately to80 bpm or slowly, by 20 bpm every 5-10sec.

3. If overpacing fails, underpacing may be attempted with thewire situated in either atrium (for SVT) or, usually, ventricle(for either SVT or VT). A paced rate of 80-100 bpm mayproduce a refractory period sufficient to suppress the

intrinsic tachycardia.4. Epicardial pacing performed during cardiac surgery requiressitting of either two epicardial electrodes or one epicardialand one skin electrode (usually a hypodermic needle). Thepacing threshold of epicardial wires rises quickly and maybecome ineffective after 1-2 days.


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Technique (for endocardial electrodeplacement)

1. If using fluoroscopy, move patient to X-ray suite orplace lead shields around bed area. Place patient onscreening table. Staff should wear lead aprons.

2. Use aseptic technique throughout. Insert 6Fr sheath ininternal jugular or subclavian vein. Suture in position.

3. Connect pacing wire electrodes to pacing box (black =negative polarity = distal, red = positive polarity =proximal). Set pace maker to demand. Check box isworking and battery charge adequate. Turn pacing

rate to > 30 bpm above patients intrinsic rhythm. Setvoltage 4V.


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4. Insert pacing wire through sheath into central vein. Ifusing balloon catheter, insert to 15-20cm depth theninflate ballon. Advance catheter, viewing ECG monitorfor change in ECG morphology and capture of pacing

rate. If using screening direct wire toward the apex ofthe right ventricle. Approximate insertion depth from aneck vein is 35-40 cm.

5. If pacing impulses not captured, (deflate balloon),withdraw wire to 15 cm insertion depth then repeat

step 4.6. Once pacing captured, decrease voltage bydecrements to determine threshold at which pacing isno longer captured. Ideal position determined by athreshold


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External pacing

External pacing can be rapidly performed by placementof two electrodes on the fron and rear chest wall whenasystole or third degree heart block has produced acutehaemodynamic compromise.

It is often used as a bridge to temporary internal pacing.It can also be used as a prophylactic measure e.g. for

Mobitz Type II second degree heart block.Indications

Asystole (in conjunction with cardiopulmonaryresuscitation)

Third degree heart block Prophylactic

Complications

Discomfort


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Technique

1. Connect pacing wire gelled electrodes to pacemaker. Place black(=negative polarity) electrode on the anterior chest wall to the

left of the lower sternum and ed (= positive polarity) electrode tothe corresponding position on the posterior hemithorax.2. Connect ECG electrodes from ECG monitor to external pacemaker

and another set of electrodes from pacemaker to patient.3. Set pacemaker to demand. Turn pacing rate to >30 bpm above

patients intrinsic rhythm. Set current to 70mA.

4. Start pacing. Increase current (by 5mA increments) until pacingrate captured on monitor.5. If pacing rate not captured at current of 120-130mA, re-site

electrodes and repeat steps 3-4.6. Once pacing captured, set current at 5-10mA above threshold.General In asystole, even though an electrical rhythm is produced by the

external pacing, this does not guarantee an adequate output isbeing generated.

Although the patient may complain of discomfort, external chestwall pacing is better tolerated and more reliable than other formsor external pacing e.g. oesophageal.

ett intubation

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