Predictors of intubation and mechanical ventilation in patients with acute respiratory failure treated with high flow nasal cannula in emergency room: the usefulness of arterial blood gas analysis

ABSTRACT

Objective@#The use of a high flow nasal cannula (HFNC) might cover the gap between conventional oxygen therapy andmechanical ventilation in the management of acute respiratory failure patients and could be a significant factor in determiningpatient outcomes. Early predictors of HFNC failure may help a clinician decide whether to shift the patient to amechanical ventilator. We aimed at identifying the predictors associated with HFNC failure and the application of amechanical ventilator using arterial blood gas analysis (ABGA). @*Methods@#We retrospectively analyzed patients who were admitted to the emergency room at a single center with respiratorydistress and a PaO2/FiO2 ratio (ratio of arterial partial pressure of oxygen to fraction of inspired oxygen) of less than300. Comparing keeping and weaning HFNC groups with the escalation group, we sought to identify a few discriminatingfactors. Initial ABGA was done when the patients entered the emergency room and this was followed up within 2 hoursafter HFNC therapy. @*Results@#Two hundred and eighteen patients were enrolled and of these HFNC therapy succeeded in 153 and failed in65. At baseline Glasgow Coma Scale, follow-up (F/U) pH, ΔpH, and F/U respiratory rate-oxygenation index were lowerand pro-brain natriuretic peptide, initial lactate, F/U lactate, ΔPCO2, heart rate, acidosis, consciousness, oxygenation,respiratory rate score, Acute Physiology And Chronic Health Evaluation score, Simplified Acute Physiology Score, andSequential Organ Failure Assessment score were significantly higher in the HFNC failure group. The results of the multivariateanalysis indicated that initial lactate (odds ratio [OR], 1.215; 95% confidence interval [CI], 1.081-1.366; P=0.001)and ΔpH (OR, 0.000; 95% CI, 0.000-0.018; P<0.001) were independently associated with the prediction of application ofthe mechanical ventilator. @*Conclusion@#Patients who had higher initial lactate levels and insufficiently corrected pH after HFNC therapy may needto be monitored carefully and escalation of oxygen therapy may need to be considered.