Hyperangulated versus Macintosh blades for intubation with videolaryngoscopy in ICU: the randomised multicentre INVIBLADE-ICU trial study protocol

Background and rationale

Compared with the operating room, tracheal intubations in the intensive care unit (ICU) are associated with worsened glottic view, decreased first-time success rate and increase in the technical difficulty of intubation and incidence of complications.1–3 Videolaryngoscopes have been proposed to improve airway management, and the use of these devices is recommended as first-line or after a first-attempt failure using direct laryngoscopy in ICU airway management algorithms.4

Although until relatively a few years ago there were doubts about whether videolaryngoscopes had advantages over direct laryngoscopy for endotracheal intubation in critically ill patients, two recent studies (DEVICE trial,5 INTUBE subanalysis6 7), a Cochrane review8 and a meta-analysis9 have confirmed that these devices improve intubation conditions in this patient population. The DEVICE trial5 was a multicentre, randomised study conducted in the USA that compared videolaryngoscopy with direct laryngoscopy for tracheal intubation in 1417 critically ill patients. The use of a videolaryngoscope resulted in a higher incidence of successful intubation on the first attempt compared with direct laryngoscopy (85% vs 71%). The subanalysis of the INTUBE study6 was a prospective, cohort study conducted internationally with 2916 critically ill patients intubated in 29 different countries. A videolaryngoscope was used for endotracheal intubation in 500 patients (17%) while direct laryngoscopy was used in 2416 (83%). The use of videolaryngoscopy was associated with a higher incidence of successful intubation on the first attempt (84% vs 79%). In the Cochrane review,8 the use of videolaryngoscopy was associated with improved glottic visualisation and fewer failed intubation attempts and complications such as hypoxaemia when compared with direct laryngoscopy. Araújo et al9 performed a meta-analysis, including 14 randomised controlled trials and 3981 patients comparing videolaryngoscopy versus direct laryngoscopy in critically ill patients, and they demonstrated that videolaryngoscopy is a more effective and safer strategy compared with direct laryngoscopy for increasing successful intubations on the first attempt, improving glottic visualisation and reducing oesophageal intubations in critically ill patients. After these results, they recommend the routine use of videolaryngoscopy in critically ill patients.

While we are beginning to accumulate evidence supporting the use of videolaryngoscopes as the preferred devices for intubating critically ill patients in the ICU, there is still a lack of clarity regarding the choice between a standard Macintosh blade or a hyperangulated one,10 to determine which leads to the best outcomes. In the DEVICE trial,5 a standard Macintosh blade was used in 85% of patients intubated with a videolaryngoscope while a hyperangulated blade was used in 15%. In the INTUBE subanalysis study,6 a hyperangulated blade was used in 25% of patients intubated with a videolaryngoscope, and the standard Macintosh blade was used in 75%. These studies do not describe the reasons for choosing one blade over the other.

The purpose of this prospective multicentre randomised study is to compare successful intubation on the first attempt with the Macintosh videolaryngoscope versus the hyperangulated videolaryngoscope during tracheal intubation in ICU patients. We hypothesise that tracheal intubation using the hyperangulated videolaryngoscope will improve the frequency of successful intubation on the first attempt in critically ill patients requiring intubation in the ICU.

Study aims and objectives

Study design

The INtubation VIdeolaryngoscopy BLADE-ICU (INVIBLADE-ICU) study is a prospective, multicentre, open-label, interventional, randomised, controlled superiority study.