1. Noninvasive ventilation (NIV) was superior to standard oxygen therapy (SOT) in reducing reintubations for patients with hypoxemic respiratory failure after abdominal surgery.
2. NIV also showed decreased the rate of health care-associated infections, especially pneumonia without an increase in serious adverse events
Evidence Rating Level: 1 (Excellent)
Study Rundown: One of the most dangerous complications during the postoperative period is acute respiratory failure, which often requires tracheal intubation and mechanical ventilation. While standard oxygen therapy (SOT), utilizing supplemental oxygen delivered via diffusion, is considered standard care for many postoperative patients, some have suggested that noninvasive ventilation (NIV) may be superior. In this randomized controlled trial, abdominal surgery patients showing signs of hypoxemic respiratory failure were randomly assigned to SOT or NIV groups. NIV resulted in superior outcomes, including reduced reintubations, decreased time under mechanical intubation and ventilator free days, and fewer health care-associated infections, especially for ICU-acquired pneumonias. In addition, there was no difference between the rates of serious adverse effects between the SOT and NIV groups.
This trial strongly suggests that NIV may be beneficial for postoperative patients after abdominal surgery who develop acute respiratory failure, though more investigation is required to generalize these findings to recovery from other surgical procedures. In addition, the study was underpowered and could not resolve if there was a decrease in mortality at 90 days, though the data trended in that direction and were likely to be significant with a larger cohort. Finally, most of the patients in this cohort were male (76%) and over the age of 60 (~62%), limiting the generalizability of these findings to other patient populations.
In-Depth [randomized controlled trial]: A total of 300 patients with acute respiratory failure within 7 days of abdominal surgery were randomized to an NIV or SOT group, with 7 patients being removed from the study due to ineligibility or revoked consent. Patients in the SOT group received up to 15 L/min of oxygen via nasal cannula or face mask, while those in the NIV group received oxygen through a face mask connected to a ventilator with titratable pressure and FiO2 levels. Exclusion criteria included DNR status, contraindications to NIV, sleep apnea, immediate tracheal reintubations, requirement for an emergent surgical procedure, and previous recruitment in another trial. NIV reduced the rate of reintubations by 12.4% (95%CI -23.5% to -1.3%) without significant differences in gas exchange or number of patients requiring reintubations for reoperation. NIV resulted in more ventilator free days (2.2 days, 95%CI 0.1 to 4.6 days) and fewer health care-associated infections (-17.8%, 95%CI -30.2% to -5.4%), especially for ICU-acquired pneumonia (p = 0.003). At 90 days after surgery, the mortality rate for the NIV patients was 14.9% compared to SOT patients at 21.5%, though this difference was not significant (p = 0.15).
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