Airway Management In Critically Ill Patient

Presenter: Dr Sazwan RSEP HOSHAS

Introduction

• This paper outlines the variations in RSI practice and the rationale for deviation.

• Such discussion is necessary, as expert opinion referring to a ‘standard’ RSI may be inappropriate for the critically ill patient.

Rapid Sequence Induction and Intubation: a standardised

process or not?

• Those working in acute care area must be able to perform basic airway management (maintenance of oxygenation and ventilation) this by use of adjuncts:

suction oro- and nasopharyngeal airwaysbag-mask ventilation and placement of a laryngeal mask in the truly

obtunded

• However, RSI is expected of advanced airway• practitioners, with indications including:• failure to maintain airway patency by other means• failure of airway protection• failure of ventilation or oxygenation• for anticipated clinical course• to facilitate transportation• for humanitarian reasons

• Despite the universal acceptance of RSI as the ‘gold standard’ in securing the airway in a critically ill patient, the actual components of RSI are known to differ markedly between individuals, institutions and countries, as well as between practitioners in different arenas (prehospital, ED, ICU or OT)

• Documented modifications to RSI technique include

patient position preoxygenation strategies pre-RSI decompression of gastric

contents with a NG tube choice and method of

administration of induction agent application of cricoid pressure choice of paralysing agent use of manual ventilation and options for failed RSI

Key elements of RSI remain, namely:

• pre-oxygenation or denitrogenation to prolong time to critical desaturation.

• prevention of hypoxia and hypotension during the induction and intubation sequence.

• passage of a cuffed endotracheal tube with confirmation of placement.

RSI of the Critically Unwell Patient

Airway Team and Dynamics

• Regardless of the individual expertise of the intubator, team factors will impact on performance of the RSI process.

• Team members should be adequately trained prior to involvement in airway management, preferably involving simulation training.

• Airway teams should regularly engage in simulation training, using their own equipment and personnel, simulating both common and uncommon scenarios.

• This may include common critical care presentations, but will also incorporate changes in team members, equipment failure and other measures to encourage understanding of human factors in team performance.

Shadow Board Kit Dump with Challenge-Response Checklist

AIRWAY PLAN- EMERGENCY RSI

Patient Positioning, Optimisation and Monitoring

• The challenge is to combat hypotension & regurgitation.

• How? in a recumbent position, with legs raised (an

attempt to counteract hypotension) and the trunk raised 30 degrees (to counteract regurgitation)- Stept and Safar

procedure of cricoid pressure in a steep head-down position with head and neck extended- Sellick

Suggestion:• ramped position referred to

as the ear-to-sternum position as it results in the external auditory meatus being at the same horizontal level as the sternum.

Recommendation

• Patients should receive preoxygenation in a head-elevated position whenever possible.

• For patients immobilized for possible spinal injury, reverse Trendelenburg position can be used.

• Airway team members, monitors and equipment should be appropriately positioned to maximise visual cues and not hinder 360 degree access to the patient.

• A timer should be used both for pre-oxygenation and to facilitate rapid progression through agreed airway plans.

Pre-O2

• critically ill patients may require a longer period to denitrogenate and are often unable to perform eight vital capacity breaths.

• use of standard reservoir face masks on maximal oxygen flow and supplemented with nasal cannulae on maximal flow.

• use of standard bag-valve-mask devices commonly used in ED, ICU or by emergency medical services. Caution is needed as such devices may entrain room air duringspontaneous ventilation . Addition of a PEEP valve to the expiratory port of BVM assembly obviates this.

• use of existing non-invasive ventilation modes.

• Patients near an SpO2 of 90% are at risk for precipitous desaturation, as demonstrated by the shape of the curve.

SpO2 less than 91%?

• CPAP masks, noninvasive positivepressure ventilation, or PEEP valves on a bag-valve-mask device should be considered for preoxygenation and ventilation during the onset phase of muscle relaxation in patients who cannot achieve saturations greater than 93% to 95% with high FiO2.

• is a strain gauge capable of PEEP settings from 5 to 20 cm H2O.

• When placed on the exhalation port of a bagvalve- mask device (inset), it allows the device to provide PEEP/CPAP when the patient is spontaneously breathing and during assisted ventilations.

• If combined with a nasal cannula set to 15 L/minute, it will provide CPAP even without ventilations.

• The generation of positive pressure is predicated on a tight mask seal.

Apneic oxygenation

• Apneic oxygenation can extend the duration of safe apnea when used after the administration of sedatives and muscle relaxants.

• A nasal cannula set at 15 L/min.• The nasal cannula can be placed under a facemask

(or bag-valve-mask device) during preoxygenation, and then it remains on, administering oxygen through the nose throughout oral tracheal intubation with direct or video laryngoscopy.

The Rule of 15’s

• Every patient gets a Nasal Canulae @15 L/min• Try adding a Non-Rebreather Mask at 15

L/min• If that doesn’t get the Sat to >= 95%, change

to BVM on 15 lpm with a PEEP valve set to up to 15 cm H20 Water

# assisting ventilation if above failed

Choice and Timing of Induction Agent

• Ketamine is gaining favour within emergency and critical care circles due to relative cardiovascular stability.

• weight-based drug calculations may not be appropriate in critical illness due to adverse haemodynamic effects.

• Fentanyl? Pro & cons. Synergistic effect?

Cricoid pressure (1961)

• Application of cricoid force remains a recommendation during RSI from the authors of the NAP4 audit in the United Kingdom. (2011)

• Hence, despite a lack of absolute evidence of benefit, cricoid force may continue to be applied; reflecting medico-legal concerns as individual clinicians have been criticised for failing to apply cricoid force in post-event medico-legal dissection of airway catastrophes.

Paralytic agent

• Succinylcholine- norm RSI• Rocuronium at a dose of 1.6 mg/kg gives the

same onset of muscle relaxation as succinylcholine and is suggested as the preferred choice of non-depolarising neuromuscular blockers for RSI in the critically ill. (Curley GF. Rapid sequence induction with rocuronium – a challenge to the gold standard. Crit Care. 2011;15(5):190)

Why Rocuronium?• It is hypothesized that the fasciculations induced by

succinylcholine may cause increased oxygen use.• Studies: In a study of operative patients, the time to

desaturation to 95% was 242 seconds in patients receiving succinylcholine versus 378 seconds in a group given rocuronium.

• In obese patients undergoing surgery, the succinylcholine group desaturated to 92% in 283 seconds versus 329 seconds in the rocuronium group

• Pretreatment medications to prevent fasciculations minimize the difference in desaturation times

Manual Ventilation between Induction and Intubation

• Manual ventilation has traditionally been avoided in classical RSI, due to concerns of gastric insufflation and aspiration.

• Exception: gentle ventilation has been advocated in both obstetric and paediatric RSI due to concerns of rapid desaturation.

• For the critically ill patient, risks of hypoxia and hypercapnia may require gentle manual ventilation.

Maximising First-Pass Success

• Careful and sequential visualisation of landmarks and avoidance of repeated attempts causing airway trauma are key skills.

• Adjuncts such as a bougie commonly used in cases of difficult intubation.

• Stylets, if used, should be shaped ‘straight-to-cuff’ i.e. the stylet should remain straight as far as the proximal part of the endotracheal tube cuff where it should be angled to no more than 35 degrees (angles beyond 35 degrees increase difficulty)

• hang-up of the bougie on the endotracheal tube connector may impede smooth rail-roading of the endotracheal tube, causing delay in tube passage (Common practice)

• pre-load an endotracheal tube onto a bougie and hold them in such a grip that control of the bougie is maintained during navigation to the laryngeal inlet.

The Vortex approach

• to optimise rescue techniques whether through endotracheal intubation, placement of a supra-glottic airway or rescue bag-mask ventilation.

Post-Intubation Care

• Haemodynamic instability.• Counter by: preloading fluid dose reduction in the haemodynamically

compromisedopioid to blunt response to intubation in the head

injured) post-RSI monitoring of heart rate and blood

pressure

Delayed Sequence Intubation (DSI)

Concept

• the technique of DSI temporally separates administration of the induction agent from the administration of the muscle relaxant to allow adequate preintubation preparation.

• induction agent allows the continuation of spontaneous breathing and the retention of airway reflexes Ketamine.

• recommended initial dose of ketamine was 1 mg/kg; additional aliquots of 0.5 mg/kg till the patient was in a dissociated state.

Then:1. 30-degree head-up (semi-Fowler)2. then received preoxygenation and denitrogenation with high-

flow oxygen, using nonrebreather masks & nasal canula 15 L/min.

3. If the nonrebreather mask was insufficient to raise the pulse oximeter saturation > or equal to 95%, the patients began receiving (NIPPV) continuous positive airway pressure settings of 5 to 15 cm.

4. after 3 min then paralytic agent5. nasal canula 15L/min for 45-60 second.6. Finally intubation

• Indication: Intolerance of

nonrebreather mask Intolerance of NIPPV Intolerance of

nasogastric tube placement for UGIB

• In patients with high blood pressure or tachycardia, the sympathomimetic effects of ketamine may be undesirable.

• these effects can be blunted with small doses of benzodiazepine ,labetalol , a preferable sedation agent is available for these hypertensive or tachycardic patients.

• Another advantage of DSI is that frequently, after the sedative agent is administered and the patient is placed on non-invasive ventilation, the respiratory parameters improve so dramatically that intubation can be avoided

Managing Initial Mechanical Ventilation

Ventilate a critically ill pt

2 types:• lung protective strategy (ARDS)• obstructive lung ( Asthma/COAD)

Lung Protective Strategy• focuses on low-tidalvolume ventilation to reduce ventilator-

associated lunginjury such as barotrauma and volutrauma.• The lung protective strategy is based on the ARDSNet ARMA study.• Immediately after intubation, decrease the FiO2 to 30% to 40%

and assign the patient a PEEP of 5 cm H2O. • Using the chart (FiO2 and PEEP scale from ARDSnet ARMA trial)

rapidly titrate to PEEP-FiO2 combinations that result in an SpO2 of 88% to 95%.

• In patients who are already demonstrating established severe acute lung injury (PaO2/FiO2 <200 mm Hg), rapid titration of the tidal volume to 6 mL/kg should occur even if the plateau pressures are acceptable.

Obstructive ventilation

As the patient’s bronchospasm improves, his or her flow or time graph will begin to look like the normal patient’s (dottedline); at this point, you may gradually up-titrate the respiratory rate.

References:

THE END

• slideshare.net/drwaque