HFNC might protect non-severely Hypoxemic patients against adverse events during intubation
Optimal preoxygenation is a crucial requirement to proceed to a safe and rapid intubation, preventing one of the most feared complications, Hypoxaemia. Severe hypoxaemia happens in 20-25% of cases , in particular in patients with Acute Respiratory Failure, and therefore most studies have compared the use of different devices (Non-Invasive Ventilation [NIV], High-Flow Nasal Cannula [HFNC] and Standard Bag-valve mask Oxygenation [SBO]) in this population [1, 2].
Current trends seem to favour NIV to prevent Hypoxaemia, as it provides both supplemental oxygen and ventilation from the start of preoxygenation until laryngoscopy. However, new studies on different populations have opened up new perspectives for preventing other serious adverse events.
The PROTRACH study is a multicentre randomised controlled trial focused on non-severely hypoxemic patients requiring intubation in the ICU.
Christophe Guitton and his team compared the use of HFNC versus SBO in 192 patients from seven mixed ICUs; the primary end-point was the lowest pulse oximetry throughout the procedure.
The study failed to find any significant difference between the median lowest SpO2 [IQR] during the intubation for both groups. Nevertheless, for the secondary outcomes, the HFNC preoxygenation was associated with a fivefold decrease in oxygen desaturation below 90%, and a fourfold decrease in intubation related complications. These complications ranged from severe (such as death, cardiac arrest, SpO2 <80%, severe hypotension requiring vasopressor initiation or a 30% increase for the initial treatment) or moderate, like arrhythmias, oesophageal intubation, vomiting or dental injury.
These results are even more surprising, as the HFNC group included a higher number of difficult intubations and intubations for Acute Respiratory Failure (p=0>009), which suggests the possibility of reducing a greater number of complications, if the devices are adapted to the characteristics of the patients.
STUDY STRENGTHS & LIMITATIONS
Limitations are related to the fact that blinding would have been difficult to maintain and therefore, unblinded preoxygenation might have biased the findings. Moreover, EtCO2 values, which could have been a better indicator of FRC oxygen saturation, were difficult to assess with the HFNC.
This said, the study remains the first, large multicentre randomised study focusing on the place of HFNC preoxygenation for endotracheal intubation in non-severe hypoxemic patients, and the benefits in terms of safer intubation by reducing other adverse events are a new, potential field to explore.
TAKE HOME MESSAGE
Compared to SMO, HFNC did not improve the lowest SpO2 during intubation in non-severely hypoxemic patients in ICU. Nevertheless, HFNC was significantly associated with fewer intubation related adverse events in this kind of patients.
This article review was prepared and submitted by Silvia Calvino on behalf of the ESICM Journal Club.
1) Non-invasive ventilation versus high-flow nasal cannula oxygen therapy with apnoeic oxygenation for preoxygenation before intubation of patients with acute hypoxemic respiratory failure: a randomized, multicentre open-label trial. Frat JP, Ricard JD, Quenot JP, Pichon N, Demoule A, Forel JM, Mira JP, Coudroy R, Berquier G, Voisin B, Colin G, Pons B, Danin PE, Devaquet J, Prat G, Clere-Jehl R, Petitpas F, Vivier E, Razazi K, Nay MA, Souday V, Dellamonica J, Argaud L, Ehrmann S, Gibelin A, Girault C, Andreu P, Vignon P, Dangers L, Ragot S, Thille AW; FLORALI-2 study group; REVA network. Lancet Respir Med. 2019Apr; 7(4):303-312. doi: 10.1016/S2213-2600(19)30048-7. Epub 2019 Mar 18.
2) High-Flow Nasal Cannula Versus Bag-Valve-Mask for Preoxygenation Before Intubation in Subjects With Hypoxemic Respiratory Failure. Simon M, Wachs C, Braune S, de Heer G, Frings D, Kluge S. Respir Care. 2016 Sep;61(9):1160-7. doi: 10.4187/respcare.04413. Epub 2016 Jun 7.