Awake Bronchoscopic Intubation With a Noninvasive Positive Pressure Support in Critically Ill Patients

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With great interest, we read the article by Johannes et al (1), in a recent issue of Critical Care Medicine, describing a technique of awake bronchoscopic endotracheal intubation (ABETI) for respiratory failure in nine patients with right heart failure and pulmonary hypertension. In this study (1), the authors demonstrate the successful use of ABETI during spontaneous ventilation supported by high-flow nasal cannula oxygen or noninvasive positive pressure ventilation in all patients. Thus, they conclude that this technique may be feasible alternative to standard direct laryngoscopy approach. Given that pulmonary hypertension and right heart failure may result in an increased risk of hemodynamic collapse during and immediately after endotracheal intubation, their technique has the potential implications. Other than the limitations described in the discussion section, however, there are several aspects of this study (1) that need to be clarified before adoption into routine practice.
First, the authors seemed to only perform the topical anesthesia of the upper airway including the oral cavity, the supraglottic area, and the glottis, but not the topical anesthesia of the trachea. It must be emphasized that alone use of sedation and analgesia without an adequate topical anesthesia of the trachea is not enough to effectively depress the patient’s response to stimulation by inserting bronchoscope and endotracheal tube (2). This can result in severe hyper-hemodynamic responses, which are unbeneficial to critically ill patients. We are concerned that adverse hemodynamic responses by ABETI would have contributed to the worsened cardiac and pulmonary functions within 1 hour after intubation in this study (1).
Second, the most commonly used sedation and analgesia agents for ABETI were midazolam and fentanyl. However, the readers were not provided the time relationships between administration of two drugs and procedure of ABETI. When using midazolam and fentanyl in low doses for awake intubation, it is best to deliver two drugs in such a way that their peak site effects occur at the same time and hence obtain most effective sedation and analgesia for awake bronchoscopy and intubation. After a bolus injection, the times from drug administration to peak effect for fentanyl and midazolam are 5 (3) and 9.7 minutes (4), respectively. Therefore, the optimal administration scheme for two drugs should be that midazolam and fentanyl were started 10 and 5 minutes before ABETI, respectively.
Third, the authors reported that all patients were able to tolerate ABETI, but they did not specify how patient’s tolerance to ABETI was evaluated in this study (1). It is generally believed that adequate sedation and analgesia regimen for awake intubation should ensure adequate intubating conditions and hemodynamic stability and can provide patient safety and comfort (5). Especially, we are very interested in knowing cough severity of patients, a pivotal variable for intubating conditions and patients’ comfort during ABETI (6).
Finally, this study (1) is only a retrospective analysis and does not compare direct laryngoscopy and bronchoscopy for awake intubation in respiratory failure patients with right heart failure and pulmonary hypertension. Thus, we do not agree with the authors’ conclusion that the ABETI supported with a noninvasive positive pressure delivery system may be feasible alternative to standard direct laryngoscopy approach.
We believe that addressing above issues would further clarify the transparency of this study (1), and such information is useful for others who would like to try ABETI with this technique.
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