We will be discussing evidence-based peri-intubation practices. Neither author reports any conflict of interest. The objectives of this talk are to discuss the peri-intubation, pre-intubation, intubation, and post-intubation time periods and their evidence-based care. We will also discuss future directions in the field of endotracheal intubation research. In the critically ill, as the natural histories of several disease states devolved into conditions with hypoxia, hypercapnia, and severe encephalopathy, endotracheal intubation is a commonly performed procedure in the intensive care unit. There are discrete periods of the endotracheal intubation procedure which have evidence-based works behind them. Approximately 45% of intubations are complicated by adverse events, as demonstrated in a recent investigation. This is a higher rate of adverse events than almost any other performed ICU procedure. Difficult airways are conceptually bifurcated between anatomically and physiologically difficult airways. Physiologically difficult airways describe aspects of a patient's oropharyngeal or laryngeal anatomy which disallow visualization and or instrumentation. A physiologically difficult airway describes states of hemodynamic or ventilatory disarray during which are at risk of further deterioration as a result of one or more steps of the intubation sequence, for example, sedative agents causing hypotension during induction. The physiologically difficult airway particularly increases the risk of cardiovascular collapse during airway management. There are four predefined time periods with intubation, the pre, the during, and the post. The peri-intubation period is an area of time which encompasses the entire intubation procedure. Intubation measures are principles which should be applied during all phases of endotracheal intubation. There are five core principles. First, the availability of difficult airway equipment to include, for example, supraglottic airways, the immediate availability of vasopressors using norepinephrine as first line, cognitive aids to be readily available during times of crisis, a universal agreement to limit attempts of intubation as each successive attempts may worsen views, and calling for help early. The purpose of a rigorous pre-intubation practice is to prevent adverse events during the post-intubation period. Pre-intubation optimization consists of the sufficient gas exchange in anticipation of an apneic period as well as the maintenance of relevant hemodynamic parameters which may be impacted by both the patient's physiological state and induction agents. Mitigating the risk of a peri-intubation event starts with identifying patients who are at risk of adverse outcomes. The Makoka score, which leverages both patient and non-patient factors in its prediction of peri-intubation adverse events, has been widely employed since its validation in 2013. Scores greater than 3 predict a difficult intubation. Several scores, such as Malampati and the Wilson Risk Sum score, may predict difficult tracheal intubations based on anatomical factors. However, such scores have performed inconsistently across cohorts. While fewer in number, scores such as Hype's may identify patients at risk for hemodynamic deterioration after intubation. Between induction and the onset of apnea, sealed oxygen delivery attenuates the rapid re-nitrogenation of the functional residual capacity, or FRC, that recurs with even a few spontaneous breaths of room air. Additionally, apneic oxygenation, the continuous delivery of oxygen throughout an apneic airway period before, during, and in between attempts, aims to reduce re-nitrogenation and increase the duration of normoxia. Literature regarding the true effect size of apneic oxygenation suggests both benefit and equipoise. A recent meta-analysis of emergency department and ICU studies demonstrated that apneic oxygenation is associated with less peri-intubation hypoxemia and a higher odds of first attempt endotracheal intubation success. The best practice is to continuously supply oxygen by nasal cannula from induction through successful endotracheal intubation in all patients. Simultaneous use of sealed oxygen delivery and bag mouth ventilation at the appropriate times is generally best practice. Hemodynamic decompensation in the peri-intubation period is often multifactorial, however, may be related to the loss of vascular tone, myocardial depression, cor pulmonale, or their synergy. Optimal measures to raise both cardiac output and mean arterial pressure are often pursued. One such measure, the administration of IV crystalloids, has been examined but did not protect patients from peri-intubation hypotension, cardiac arrest, or the requirement for a new vasoactive infusion. The ideal induction agents would have a rapid onset, offset, and no hemodynamic impact. The optimal combination of existing induction medications in the ICU remains elusive. Safety is maximized when the induction agents are selected based on the needs of the patient as dictated by their pathophysiology and anatomy. In the 2021 INTUBE study, hemodynamic collapse was observed across all sedative-hypnotic agents. However, propofol was the only identified modifiable risk factor for hypotension. This leads to propofol being used less and less in the intensive care unit as primary induction agent. Automadate achieves rapid induction by potentiating the GABA-A receptor with little effect on respiratory drive. A recent meta-analysis concluded that automadate likely increases mortality compared to other agents when used for induction in the critically ill. While a single bolus of automadate results in six to eight hours of adrenal suppression, the clinical significance of this is widely debated. Notably, when automadate is used for induction for ICU patients with severe sepsis or septic shock, there was no association with mortality or additional vasoactive infusions. Ketamine achieves rapid induction by antagonizing the NMDA receptors with a likewise diminished effect on respiratory drive. Although touted as a sympathomimetic, ketamine has been associated with more post-intubation hypotension in patients with undifferentiated states such as sepsis. Historically, the studies surrounding the comparative hemodynamic profiles of automadate and ketamine are confounded by varying dosage, differences in patient populations, heterogeneous study methodologies, and a range of sample sizes. The use of automadate versus ketamine was examined in the 2022 RCT EVK. Although the cohort that received ketamine on induction displayed superior survival at day seven, at day 28, neither cohort displayed improved survival. It should be noted, however, that while widely regarded as hemodynamically stable medications, both automadate and ketamine can prompt hemodynamic collapse in patients with shock. The use of neuromuscular blockade is understood to improve rates of first-pass airway success. Rapid sequence induction with neuromuscular blockade frequently establishes optimal intubating conditions. However, neuromuscular blockade is not necessarily required for rapid sequence induction. Historically, there have been concerns that a chemically paralyzed patient may result in a cannot intubate, cannot ventilate scenario without rapid return to spontaneous ventilation. More contemporary approaches consider that Sugamidex is available for the reversal of rocuronium and for vecuronium. Neuromuscular blockade either improves or has minimal effect on mask ventilation, and neuromuscular blockade can serve as a remedy to the cannot intubate, cannot ventilate scenario. Next, we will review intraprocedural measures. The intraprocedural decisions surrounding endotracheal intubation are dictated by patient, equipment, and human factors. Complications arise from failure to address any of these elements. The traditional emphasis on rapid sequence intubation, a minimized interval from induction to intubation, does not respect the role that deranged physiology plays in hastening pulmonary and cardiovascular decompensation. Peri-intubation cardiovascular collapse is associated with a decrease in the intensive care unit free days, ventilator free days, and survival to discharge. Because physiologic abnormalities pose a significant risk of complications, even first attempt success is associated with a 15 to 19% incidence of an adverse event in acutely ill patients. Endotracheal intubation first attempt success is crucial because a second attempt is associated with a 30 to 40% increase in adverse events and serial attempts further increase risk. Positioning the patient with the head elevated optimizes functional residual capacity during pre-oxygenation and is likely of relevance after induction to prevent loss of FRC. Head up positioning also augments upper airway patency to facilitate mask ventilation. The American Society of Anesthesiologists Difficult Airway Algorithm and the Royal College of Anesthetists Difficult Airway Society Algorithm for Tracheal Intubation of Critically Ill Adults recommend a head elevated position throughout airway management. Head up position may result in a clinically significant reduction in preload. The operator must evaluate the benefits and drawbacks of head up positioning in the context of individual patient factors to balance hemodynamics and oxygenation effects. Bag valve mask ventilation during apnea, but before airway instrumentation, serves to reduce desaturation. Apneic oxygenation, the continuous delivery of oxygen throughout apneic airway management, aims to reduce re-nitrogenation and increase the duration of normoxia. Bag mask ventilation at the appropriate times is generally best practice, with caution indicated in specific circumstances, such as full stomach and acute abdomen. Literature regarding the true effect of apneic oxygenation suggests both benefit and equipoise. A meta-analysis of ED and ICU studies demonstrated that apneic oxygenation was associated with less peri-intubation hypoxemia and higher odds of first attempt endotracheal intubation success. The American Society of Anesthesiologists Difficult Airway Algorithm and the Royal College of Anesthetists Difficult Airway Society Algorithm for Tracheal Intubation of Critically Ill Adults indicate the use of low or high flow nasal cannula throughout airway management. Best practice is to continuously supply oxygen by nasal cannula from induction through successful endotracheal intubation in all patients. Laryngoscopy technique is chosen to maximize the probability of first attempt endotracheal intubation success. Contemporary research comparing outcomes of interest using direct laryngoscopy versus video laryngoscopy has been performed in various clinical settings but often lacks external validity and therefore applicability to the ICU. Although there are sundry variations to both DL and VL based on the specific device, VL generally has favorable results across the majority of publications. VL has high first attempt success rates, increased odds of first attempt success, fewer intubations classified as difficult, and fewer complications compared with DL. Moreover, VL is appropriate for first or for backup intubation attempts in the ICU. The video screen, which allows multiple individuals to view the laryngoscopy in real-time, creates opportunities for education and teamwork. A trainee performing VL can benefit from receiving real-time feedback and an expert performing VL can narrate endotracheal intubation with visual display for the benefit of learners. Additionally, because multiple people can see the screen during VL, assistance with cricothyroid pressure, suctioning, positioning, and equipment readiness is expedited. Placing a stylet in the lumen of the endotracheal tube or using a Bougie may improve the likelihood of successful endotracheal intubation when using either direct laryngoscopy or video laryngoscopy. Emergent endotracheal intubation with direct laryngoscopy had higher first attempt success rate using Bougie compared with endotracheal tube and stylet. It should be noted that stylet use carries a risk of damage to the airway. Best practice for airway management involves having a primary plan and at least one backup plan. When the primary plan fails, multiple options exist for initiating a backup plan. These center around the following, changing the equipment that is being used for airway management, changing the patient by manipulating some aspect of the anatomy or the positioning, changing the operator, primarily by changing to someone with greater experience or expertise, and finally, changing the approach, such as a rescue supraglottic airway, fiberoptic intubation, or a surgical or percutaneous solution. In keeping with utmost preparation for an unanticipated difficult airway, a selection of airway equipment that is occasionally required should be readily available to the intubating team. This includes items such as laryngeal mask airways, retrograde wire kits, tracheostomy instruments, fiberoptic scope, and video laryngoscope batteries. Ideally, all such equipment is stored in a portable cart to preclude an urgent search when initial attempts at endotracheal intubation fail. Predictably, several human factors affect the success and complication rates of endotracheal intubation. Although the best practices for intensive care units are principally dictated by local factors, the proliferation of work on human factors in airway management indicates that at least having an intensive care unit airway management protocol or similar guide in place is an essential step in reducing complications. While literature globally recommends limiting the number of attempts at intubation, the American Society of Anesthesiologists Difficult Airway Algorithm specifically highlights this. A general rule of thumb is to limit the number of attempts at two per operator and two per technique. Repeated attempts at endotracheal intubation typically decrease the success of subsequent attempts because of increasing edema, injury, or bleeding in the airway. The literature globally recommends calling early for help. Once again, this is highlighted in the ASA DAA. Next we'll focus our attention on post-intubation best practices. The priority in the post-procedural period is confirmation of endotracheal intubation. The consequences of an unrecognized esophageal intubation may be fatal. Many commonly used methods of endotracheal intubation confirmation are surrogates rather than indicators of endotracheal tube placement. The American Society of Anesthesiologists standards indicate that when an endotracheal tube is inserted, its correct positioning must be verified by clinical assessment and by identification of carbon dioxide in the expired gas. For a metric, CO2 detection must be sustained to rule out esophageal intubation. Waveform capnography is optimal if available. Bronchoscopy is nearly definitive for demonstrating appropriate location of endotracheal tube tip. Often, the duration of action of the neuromuscular blockade exceeds that of the sedative given with it. As such, patients who undergo rapid-sequence intubation are at risk for awareness with paralysis. Awareness with paralysis has been examined in patients who have undergone endotracheal intubation in the emergency department, and the incidence has been cited around 7.4%. At the time of the decision to undertake endotracheal intubation, the post-intubation plan for sedation should be clarified with its execution ready at the end of the procedure. Best practice for endotracheal tube cuff inflation is to inflate the cuff just to seal against the pressure of the ventilator. Manometry can be used to assure that the pressure of the cuff is under 30 mmHg, which is generally accepted as the pressure at which tissue damage will occur in the trachea. Unless contraindicated, post-intubation recruitment maneuver can be used to counter atelectasis from induction. While I found no particular studies indicating evidence for post-intubation team debriefing, there are plenty of examples in the literature from other procedures where debriefing improves the quality over time. As such, post-intubation team debriefing should be used locally for local improvement and quality assurance. Because airway management in the intensive care unit is incredibly complex, there are many opportunities for improvement going forward. Airway management has benefited from decades of rigorous study, and its application to critically ill patients offers many opportunities for improvement. Subsequent investigations should endeavor to determine the optimal use of video laryngoscopy versus direct laryngoscopy. Novel airway devices require a focus on rapid mastery, high success rates, and wide applicability if they are to supplant current intubation technology. Given the incidence and potentially devastating effects of hemodynamic collapse after induction, the development of a novel, truly hemodynamically neutral induction agent would be a welcome addition to the existing pharmaceutical armamentarium. Finally, a formalized critical care medicine airway curriculum has the potential to standardize care and lead to a greater appreciation of the risks of intubating critically ill patients. In conclusion, best practices for the management of the airway of the critically ill patient focuses on two simultaneous goals, first attempt success and avoidance of adverse events. A complex interplay of both patient and environment influences the optimal strategy. Best practices are informed by research and expert opinions, however, such recommendations must be contextualized to the bedside clinical decision making. We thank the Society of Critical Care Medicine for the opportunity to bring this information to you.

peri-intubation practices

intubation scores

difficult airway management

induction agent selection

neuromuscular blockade

airway management research