Just as I set the last blog post in the airway series to post, a fantastic set of guidelines on intubation in critically ill adult patients was published. It covers most of the content I tried to cover in those posts, and probably does a much better job. I recommend that everyone take the time to read it. I have already covered a lot of this information in the airway series, but as a way of reinforcing the lessons from those posts, I thought I would go through my personal takeaways from this document.
Critically ill patients are different
They recognize that airway management in critically ill patients is not the same as managing healthy elective surgery patients, and that specific evidence and guidance for these special scenarios is comparatively lacking.
Team factors and ergonomics are essential
I love that they start this guideline by talking about human factors. Although we love to talk about the anatomy of the airway, human factors are the core of many of the airway difficulties we encounter. Human factors were the most prevalent cause of error identified in the NAP4 audit. In fact, there were a median of 4.5 human factors issues in each NAP4 case. The most common problem was loss of situational awareness.
The design of our resuscitation spaces is often far from ideal. If you are the clinician intubating the patient, the monitor if often behind your head, which makes very little sense. Possible solutions are resdesigning our resuscitation rooms, adding mirrors, or having one team member specifically tasked to monitoring the vitals and feeding back to the team. I particularly like that they even go into detail of the best ways to arrange our team depending on the number of providers that are present.
They state that cognitive aids are essential to improve performance performance in stressful situations. Use of a standardized airway algorithm is recommended. They also recommend the use of checklists.
Airway equipment should be standardized across the hospital.
Reporting and no-blame discussions of bad outcomes and near misses are essential.
They recognize that airway assessments are not very reliable (have a low positive predictive value and imperfect sensitivity). The only airway tool that has been validated in critically ill patients is the MACOCHA score. A score of 3 or greater predicts difficult intubation.
In critically ill patients, shunt physiology often contributes to difficulties with pre-oxygenation. If you are having trouble getting the patient’s oxygen saturation up before intubation, they emphasize the use of CPAP, non-invasive ventilation, and head up positioning. They warn that gastric insufflation may occur when pressures of 20 cm H20 or higher are used.
In patients in whom agitation interferes with adequate preoxygenation, they suggest the use of delayed sequence intubation.
They suggest positioning the patient with the head of the bed up both for pre-oxygenation and during the intubation procedure if feasible.
These guidelines still do emphasize cricoid pressure. I disagree with that recommendation.
They do recommend using nasal oxygen at 15 L/min for apneic oxygenation during the intubation procedure.
Plan for failure. Failed intubation occurs in 10-30% of critically ill patients. It should be anticipated. Have a triggered transition to front of neck access.
The algorithm they describe is fairly similar to the one that I describe in part 3 of the airway series.
Second generation LMAs, with design features specifically intended to reduce the risk of aspiration such as higher oropharyngeal seal pressures and oesophageal drain tubes (e.g. i-gel™, ProSeal™Laryngeal Mask Airway) are preferable to first generation devices and should be available anywhere where critically ill patients might be intubated.
“The ICS, DAS, National Tracheostomy Safety Project, NAP4, and National Institute for Health and Care Excellence recommend immediate availability of fibreoptic endoscopes in ICU.” They do not discuss the emergency department setting, but I would argue the two settings are very similar when it comes to airway management.
In the can’t intubate, can’t oxygenate scenario, they recommend proceeding immediately to surgical front of neck access with the scalpel bougie technique. They specifically recommend a surgical approach to front of neck access over catheter based approaches.
Do not wait for critical hypoxemia before proceeding to front of neck access. “Delayed transition to FONA because of procedural reluctance is common in airway crises and is a greater cause of morbidity than complications of the procedure.” After a single failed intubation attempt, the front of neck access equipment should be immediately at hand, and help should be summoned. After a maximum of 3 failed intubation attempts, there should be a prompt and clear declaration to the team that “this is a failed intubation”. Declaring the failure is important to prepare the team and prime the appropriate action.
“It is mandatory to use waveform capnography to confirm intubation.”
They recognise that critically ill patients are at a high risk of hemodynamic collapse in the peri-intubation period. They suggest optimizing the hemodynamics before proceeding to intubation. If possible, one team member should be assigned specifically to monitoring the patient’s hemodynamic status. They suggest ketamine as the agent of choice in high risk patients. They also suggest the proactive use of inotropes or vasopressors.