Commentary to “Hemodynamic response to endotracheal intubation using C-Trach assembly and direct laryngoscopy”

Sir,

The standard hemodynamics alterations (HA) after laryngoscopy and intubation usually are tachycardia and hypertension, although these HA use to be underestimated due to the lack of continuous monitoring at that time, with serious potential consequences on the patient.

During laryngoscopy with a conventional Macintosh blade, two main causes of these HA to tracheal intubation are stimuli to oropharyngeal structures produced by direct laryngoscopy and stimuli to the larynx and trachea exerted by tube intubation.[1]

When sympathetic afferent fibers of the cervical plexus are stimulated, a variable increase in blood pressure, transabdominal approach (TA) occurs (40-50%), which depends on the time of laryngoscopy and intubation (more marked after 45 min of laryngoscopy and maximum when laryngoscopy lasts more than 16 s). In addition, spinal cord produces a diffuse autonomic response that releases noradrenaline and adrenaline from the adrenal medulla, in addition with Renin.[1]

These HA are even more pronounced in patients with hypertension by sympathetic hyperreactivity, presenting norepinephrine circulating levels 2-3 times higher.

The heart rate also increased, especially after the 1^st min postintubation and usually return to normal after 5-10 min. The ejection fraction decreases in the 1^st min postintubation, especially in coronary patients, and exists an increase in O2 myocardial consumption of up to 25-45%, at the same time the debit of the coronary sinus O2 decreases, producing a failure in coronary self-regulation.[2]

When this occurs in a patient susceptible with associated pathologies, such as hypertension, coronary or brain arteriosclerosis, or elderly patients, sympathetic stimulation, with a sharp rise of TA, it can cause failure of the left ventricle, ischemia myocardial, or cerebral hemorrhage.

Supraglottic airway devices (SAD) have been shown to reduce these HA in patients more than endotracheal intubation since Brimacombe[3] conducted meta-analysis with classic LMA in 1995.

C-Trach is the first generation intubating laryngeal mask that allows real-time view of the airway during orotracheal intubation while maintaining optimal ventilation. However, in December 2009, LMA North America take the decision to discontinue the manufacture,[4] although is still in clinical use.

In 2011, NAP4 identified the potential advantages of the second generation devices in airway rescue and recommended that all hospitals have them available. The ideal attributes of a SAD for airway rescue are reliable the 1^st time placement, high seal pressure, separation of gastro-intestinal and respiratory tracts, and compatibility with fiber optically guided tracheal intubation.

Several second generation SADs have been described. The Totaltrack™ (TT, MedComflow S.A., Barcelona, Spain) is a hybrid device, between the second generation SAD and a video laryngoscope [Figure 1]. It allows fiber optic visualization of the larynx for tracheal intubation and was developed to aid both ventilation and tracheal intubation, at the time of anticipated and unanticipated difficult airway management.

Figure 1.

Totaltrack courtesy of MedComflow

Totaltrack™ combines the advantages of video laryngoscopy with a SAD part, with gastric suction channel, which allows to aspirate stomach content, laryngeal suction channel, that provides a means of aspirating blood or secretions, and the seal created by the inflated cuff protects the airway from aspiration until intubation is accomplished, and an adequate view of the glottis that leads to a high first-attempt intubation rate and reduces the time required to secure the airway.[5]

Nevertheless, further evaluation of its efficacy and safety, including the hemodynamic response, is required.

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Conflicts of interest

There are no conflicts of interest.