Rapid sequence induction and intubation

Question 1

Learning objectives

Answer 1

Identify the patient at risk of pulmonary aspiration
during airway management.
Generate a plan to prepare a patient safely for
rapid sequence induction and intubation (RSII).
Describe the Project for Universal Management of
Airways (PUMA) universal principles for RSII and
recall the components which are recommended,
suggested and optional.
Discuss the current evidence base supporting
various components of the RSII procedure

Question 2

Key points

Answer 2

1. Pulmonary aspiration remains the commonest cause of anaesthesia-related death and brain
   damage
2. Rapid sequence induction and intubation has evolved since its classical description; however,
   recent modifications are poorly defined
3. Adequate preparation for RSII helps to mitigate risk, increase success and address patient specific challenges
4. The PUMA collaboration has proposed universal principles for RSII.
5. The PUMA universal principles aim to overcome practice variation and outline recommended,
   suggested and optional components of RSII.

Answer 3

Pulmonary aspiration is defined as the introduction of gastric
or oropharyngeal matter into the lower respiratory tract

RSI reduce Risk:

This is achieved by minimising the time between drug-induced loss of protective airway reflexes
and the successful insertion and inflation of a cuffed tracheal tube.

National Audit Project (NAP4)
identified that pulmonary aspiration accounted for 50% of
deaths reported in NAP4, and was the most common cause of
anaesthesia related death

Despite this, 28% of
aspiration events in NAP4 occurred in fasted patients.

Question 4

Evolution of rapid sequence induction and intubation

Answer 4

More than 50 yr have passed since RSII was first
described, and a number of recent surveys of anaesthetists
suggest there is little consensus over the delivery of RSII and
practice is highly variable

Question 5

The indications for RSII can be divided into

Answer 5

(i) Patients in whom fasting has occurred but is unreliable.

(ii) Patients in whom the fasting time is inadequate or unidentified. a

Question 6

Risk factors for pulmonary aspiration

Answer 6

Fasting unreliable

Not fasted/emergency
procedure

Question 7

Fasting unreliable

Answer 7

Pregnancy (>20 weeks)

Obesity (BMI >40 kg m2)

Hiatus hernia/gastrooesophageal reflux

History of oesophageal cancer/ stricture or upper gastrointestinal
surgery/bariatric surgery/gastric outlet obstruction

Advanced chronic disease resulting in gastroparesis
(diabetes mellitus/chronic kidney disease/neuromuscular disorders

Question 8

Not fasted/emergency procedure

Answer 8

Patient who is not fasted as per local guideline or fasting status unknown

Acute intra-abdominal pathology
(bowel obstruction)

Acute pain or trauma resulting in gastric stasis

Question 9

An anaesthetist should perform RSII in the following situations:

Answer 9

(i) Patients for elective surgery who are adequately fasted but have risk factors for aspiration (e.g. hiatus hernia, gastro-oesophageal reflux, previous bariatric surgery,
oesophageal pathology, delayed gastric emptying).

(ii) Patients for emergency surgery who are not fully fasted or, regardless of fasting status, have risk factors for aspiration (e.g. bowel obstruction, gastric outlet
obstruction, acute severe pain, upper gastrointestinal
bleeding).

iii) Obstetric patients requiring elective or emergency anaesthesia.

(iv) Critical care patients who require tracheal intubation
(e.g. those with altered consciousness, respiratory failure,
or multiple trauma

Question 10

Risks of RSII

Answer 10

Adverse events may occur during RSII, the most significant of
which include hypoxia, hypotension and pulmonary aspiration.

associated with an increased risk of difficulty in airway management

The NAP4 identified that failed intubation occurs in 1 in 2,000
elective cases, but this number increases to 1 in 300 with RSII.

The incidence of failed intubation is even higher (1 in 50e100)
with RSII in the emergency department, critical care or obstetric patients

Question 11

Hypoxia

Answer 11

Hypoxia can occur despite adequate preoxygenation of the lungs
in a patient who is critically ill, obese or in the peripartum period.

Oxygen desaturation may occur even when successful intubation is performed swiftly.

Question 12

BP

Answer 12

Hypotension
and cardiovascular instability is another concern,
particularly in a frail patient or those in circulatory shock.

Question 13

pulmonary aspiration,

Answer 13

Although the objective of RSII is to prevent pulmonary aspiration,
it is recognised that this may still occur during airway
management. The risk of pulmonary aspiration also exists
during extubation of the trachea. The anaesthetist must
ensure the patient can protect their airway before removing
the cuffed tracheal tube

a nasogastric tube is present it should be aspirated before extubation.

The prospect of RSII
can generate much anxiety in patients, particularly if cricoid
pressure is planned. Anaesthetists should remain mindful of
this and explain the procedure carefully

Question 14

Preparation and performance

Answer 14

A recent Difficult Airway Society (DAS) guideline
recommends the use of an intubation checklist for RSII

developed for the critical care environment, the four headings

prepare the patient,

prepare the equipment,

prepare the team

prepare for difficulty

neatly summarise a safe approach to RSII in any group.

Question 15

The patient

Answer 15

1. An airway assessment is essential to help anticipate difficulty - MACOCHA
2. IV access
3. Position
4. Preoxygenation of the lungs is essential before RSII
5. CPAP
6. HFNO
7. NG

Question 16

MACOCHA

Answer 16

A MACOCHA score of >2 predicts difficulty

Factors Points
Mallampati class III or IV 5
Obstructive sleep Apnoea syndrome 2
Reduced mobility of Cervical spine 1
Limited mouth Opening <3 cm 1
Coma 1
Hypoxaemia 1
Non-Anaesthetist 1

Question 17

3. Position

Answer 17

PreO2 / Optimises view / Opposes passive regurgiation
Head up

The ideal patient position for RSII
is one which facilitates preoxygenation, optimises laryngoscopic
view and opposes passive regurgitation of gastric
contents. The head up position appears to meet these criteria,
but the optimal degree is not yet determined by evidence. The
most common position described in practice is 20 head up

A
‘ramped’ position with horizontal alignment of the tragus and
the sternal notch is recommenced for obese and obstetric
patients

Question 18

Checklist

Answer 18

Question 19

4. Preoxygenation of the lungs is essential before RSII

Answer 19

accumulate a reservoir of oxygen,
which will help to delay the onset of hypoxia during the period
of apnoea which follows induction and before successful
tracheal intubation and ventilation are achieved. The adequacy
of preoxygenation can be evaluated by measurement of
the fraction of expired oxygen (FE’O2). An FE’O2 of 0.85 or greater
indicates adequate preoxygenation.

using a closed
anaesthetic machine circuit with a fraction of inspired oxygen
(FIO2) of 1.0. Otherwise a semi-closed circuit such as the
Mapleson C circuit with a fresh gas flow of 15 L min1 can be
used.

high fresh gas flow is required to prevent rebreathing
with a Mapleson C circuit. Preoxygenation is performed by
tidal volume breathing of oxygen with a tight fitting facemask
for 3 min, or alternatively with eight vital capacity breath

denitrogenation of the functional
residual capacity of the lungs. Patients who are pregnant or
obese have a reduced functional residual capacity, therefore
optimal positioning and adequate preoxygenation is especially
important in these groups

In critically ill adults who
are hypoxaemic, adding continuous positive airway pressure
(CPAP) of 5e10 cmH2O during facemask preoxygenation is
advised

Continuous positive airway pressure can help prevent
the development of absorption atelectasis associated
with breathing high concentration oxygen.

Question 20

HFNO

Answer 20

There is an emerging role for high-flow nasal oxygen (HFNO) techniques
in preoxygenation and apnoeic oxygenation during RSI

there is no evidence to suggest
HFNO is a superior device for preoxygenation

standard nasal cannula may be used for apnoeic
oxygenation after loss of consciousness using an oxygen flow
rate of 15 L mi

Question 21

NGtube

Answer 21

Finally, if a nasogastric
tube is present it should be aspirated and left open to
air before RSII. The insertion and aspiration of a nasogastric
tube before RSII can be considered in patients who are likely to
a have a significant volume of gastric residue

Question 22

Equipment

Answer 22

1. Minimum monitoring,
2. Laryngoscope
3. Medications

Question 23

Evidence VL vs DL

Answer 23

Recent Cochrane r/v
concluded that when compared with direct laryngoscopy,
videolaryngoscopy results in higher rates of successful tracheal intubation on the first attempt

A videolaryngoscope
may be advantageous for RSII if difficulty is
anticipated providing the operator is familiar with its use.

tracheal tube introducer, such as a bougie, should be immediately
available to assist tracheal intubation.

Question 24

Minimum monitoring,

Answer 24

as described by the Association of Anaesthetists,
should be applied to the patient before RSII.

Waveform capnography is essential to confirm correct tracheal tube placement.

The insertion of an arterial cannula for invasive blood pressure measurement is recommended in patients with haemodynamic instability.

Central venous access may also be required for vasoactive infusions in the critically ill.

functioning airway suction device should be
available and placed under the patient’s pillow. The presence
of two active suction catheters is recommended if significant
airway contamination is likely

Question 25

The ideal medications

Answer 25

The ideal medications to induce anaesthesia in the setting of RSII are specific to the patient and the situation. Whichever agents are used, it is established practice to use predetermined doses of an intravenous anaesthetic agent and a neuromuscular blocking drug in immediate succession Although not described in classical RSII, using opioids to blunt the sympathetic response to laryngoscopy has become common practice, though this remains optional. The use of a rapid acting neuromuscular blocking drug is mandatory. The choice between rocuronium and suxamethonium is a source of debate and has been discussed recently in this journal The dose for each adjunct and induction medication is given as a range and must take account of the specific clinical context and cumulative effect if multiple agents are used. Conservative doses are required in patients who are older, frail or hypovolaemic.

Question 26

Medications for rapid sequence induction and intubation Induction

Answer 26

Propofol 1-3 mg kg/1 Universal intravenous induction agent but can cause significant cardiovascular depression Ketamine 1-2 mg kg1 Consider in patient with hypovolaemia, circulatory shock or life-threatening asthma Thiopental 3-5 mg kg1 Consider in patients in refractory status epilepticus

Question 27

Neuromuscular blocking agent

Answer 27

Suxamethonium 1-2 mg kg/1 Avoid in patients with hyperkalaemia, crush injuries and more than 24 h after severe burns Rocuronium 1e1.2 mg kg1 Reversible with sugammadex 16 mg k

Question 28

Optional adjuncts

Answer 28

Fentanyl 1-3 mg kg1 Lidocaine 1-1.5mg kg To attenuate the sympathetic response to laryngoscopy. Consider in patients with raised intracranial pressure, malignant hypertension, aortic dissection, pre-eclampsia/eclampsia or significant cardiovascular disease

Question 29

The team

Answer 29

The conduct of RSII in the critical care setting necessitates a larger team. In such cases, the following roles should be assigned before commencing the procedure: Airway management/intubator (ii) Airway assistant/application of cricoid pressure (iii) Team leader/medications/monitor/second intubator (iv) Runner (any healthcare staff member who can reliably fetch equipment)

Question 30

Cricoid

Answer 30

Perhaps the most debated element of RSII is the application of cricoid pressure pressure involves applying force to the cricoid cartilage in an attempt to compress the oesophagus between the posterior cricoid ring and the body of the fifth cervical vertebra. Sellick proposed that pulmonary aspiration could be prevented by compression of the oesophagus; studies involving radiological imaging have concluded that this is unreliable posterolaterally to the cricoid cartilage in many humans and cricoid pressure simply results in further lateral displacement of the oesophagus A Cochrane review conducted in 2015 concluded that no randomised controlled trial exists to support or refute the use of cricoid pressure

Question 31

Cricoid how to

Answer 31

Correct identification of the cricoid cartilage is essential. The cricoid cartilage is found in the midline of the neck, inferior to the thyroid cartilage. Cricoid pressure involves the application of vertical, downward pressure using the thumb and first or middle finger. A force of 10 N is applied when the patient is awake, and increased to 30 N once the patient becomes unresponsive The pressure is maintained until inflation of the tracheal tube cuff and confirmation of successful placement with waveform capnography

Question 32

Cricoid Problems

Answer 32

The application of cricoid pressure is associated with difficulty in facemask ventilation and placement of supraglottic airways. Recently a randomised controlled trial involving 3,472 patients undergoing RSII found pulmonary aspiration occurred in 10 patients (0.6%) in the group receiving cricoid pressure and in 9 patients (0.5%) in the control group Laryngoscopy was more difficult and intubation times were longer in the group receiving cricoid pressure. Studies concerning the performance of cricoid pressure by clinicians suggest that’s its use is inconsistent. survey of anaesthetists in the UK identified significant variability around the timing of its application.27 There is also concern that applying cricoid pressure can cause relaxation of the lower oesophageal sphincter, thereby increasing the risk of passive regurgitation Although its use remains controversial, it is recommended that if difficulty is encountered with airway management cricoid pressure should be released. Educating staff to apply cricoid pressure correctly is a further challenge. Training can be facilitated with the use of a biofeedback device, which indicates the amount of pressure applied in a simulated setting.

Question 33

Team other bits

Answer 33

The ergonomics of the patient, equipment and team should also be considered. If possible all team members should be able to view the patient monitor. If a second intubator is present they should be positioned appropriately, facilitating rapid handover if necessary. The monitor’s pulse oximeter tone should be audible, and this may require adjustment in the critical care or emergency department setting.

Question 34

Prepare for difficulty

Answer 34

An airway plan should be shared with the team members before RSII. The presence of all of the equipment necessary to execute the airway plan must be confirmed before commencing the procedure. In the event of failed intubation, the team should focus on rescue oxygenation. This will include facemask ventilation or the placement of a supraglottic airway. Gastric insufflation during facemask ventilation can be reduced by: Maintaining a patent airway, with airway adjuncts and two-handed technique if necessary. (ii) Restricting peak inspiratory pressures to 15 cmH2O or less during positive pressure ventilation. specific clinical context will determine if it would be appropriate to wake the patient in the event of failed intubation. If the procedure is elective this may be possible, but it is unlikely to be an option for time-critical surgery

Question 35

RSII in special groups

Answer 35

Current evidence suggests the use of classical RSII in paediatric anaesthesia is limited. A survey of British anaesthetists identified only half would use the classical RSII to intubate a child with a ‘full stomach The various anatomical and physiological differences in infants and children make the classical approach less favourable have been described previously in this journal Conversely, the use of RSII in obstetric anaesthesia has persisted. To avoid desaturation adequate preoxygenation, gentle bag-mask ventilation and apnoeic oxygenation are all recommended during RSII in obstetric anaesthesia Furthermore, because of the higher incidence of difficult airway in obstetric practice, it is suggested a videolaryngoscope be used as first line

Question 36

Defining RSII

Answer 36

The PUMA group is an international collaboration of experts who have proposed a set of universal principles for the conduct of RSII. 10 core elements that must be completed to meet the definition of RSII. Steps applicable to a standard induction of anaesthesia such as monitoring do not feature as they are not specific to RSII. The suggested components should be included but may be omitted in specific situations. The optional components are elements of the procedure for which supporting evidence is weak. This allows a practitioner to use their judgement for certain components depending on the context.

Question 37

Future directions

Answer 37

Several developments concerning RSII are ongoing. The use of paratracheal force has recently been suggested as an alternative to cricoid pressure. Paratracheal pressure has been associated with a reduction in gastric insufflation of air during positive pressure ventilation and the effects on view at laryngoscopy may be non-inferior compared with cricoid pressure The investigators also reported easier bag-mask ventilation and lower peak inspiratory pressures in the paratracheal force group. The use of ultrasound to evaluate residual gastric volume is also being explored. Gastric ultrasound could contribute to the assessment of aspiration risk for individual patients. A retrospective cohort study of fasted elective surgical patients using point-of-care ultrasound involving 538 patients found that 6.2% presented with a ‘full stomach’ that gastric ultrasound is highly sensitive and specific when identifying residual gastric content.34

Question 38

Project for Universal Management of Airways (PUMA) universal principles for rapid sequence induction. Recommended

Answer 38

Preoxygenation Suction turned on and placed under the pillow Confirmed and reliable intravenous access Tracheal introducer prepared Predetermined dose of induction agent No latency between giving induction agent and NMBA Use of rapid-onset NMBA Apnoeic oxygenation between attempts at laryngoscopy if facemask ventilation not used Confidence in complete paralysis before instrumenting airway Tracheal tube cuff inflation before positive pressure ventilation

Question 39

Suggested

Answer 39

Apnoeic oxygenation during attempts at laryngoscopy Able to adopt Trendelenburg position if regurgitation occurs Suction and leave open to air an in situ nasogastric tube

Question 40

Optional

Answer 40

Prokinetic drugs Non-particulate or intravenous antacids Nasogastric tube placement and suction Avoid agents with potential sedative or hypnotic effects before induction Avoid facemask ventilation before laryngoscopy Position change Cricoid pressure