Addition of 10 cm H2O to positive end-expiratory volume (PEEP) during mechanical ventilation was followed by significantly lessened pulmonary complications in hospitalized patients who developed hypoxemia after cardiac surgery, participating in a single-center, randomized trial.
This “intensive” alveolar recruitment strategy yielded a median pulmonary complications score of 1.7 (interquartile range, 1.0-2.0), compared with 2.0 (IQR, 1.5-3.0) among patients who underwent ventilation with a PEEP of 20 cm H2O, Alcino Costa Leme, RRT, PhD, said at the International Symposium on Intensive Care and Emergency Medicine. The report was published simultaneously online March 21 in JAMA.
Intensive alveolar recruitment nearly doubled the odds of a lower pulmonary complications score (common odds ratio, 1.9; 95% confidence interval, 1.2-2.8; P = .003), Dr. Leme and his associates reported.
The study comprised 320 adults who developed hypoxemia immediately after undergoing elective cardiac surgery at the Heart Institute (Incor) of the University of São Paulo. The median age of the patients was 62 years, and none had a history of lung disease. Pulmonary complications were scored between 0 (no signs or symptoms) and 5 (death), the investigators noted (JAMA. 2017 Mar 21. doi: 10.1001/jama.2017.2297).
The intensive alveolar recruitment strategy consisted of three 60-second cycles of lung inflation with a positive end-expiratory pressure (PEEP) of 30 cm H2O, pressure-controlled ventilation, driving pressure of 15 cm H2O, respiratory rate of 15/min, inspiratory time of 1.5 seconds, and FIO2 of 0.40. Between and after inflations, patients received assist-controlled or pressure-controlled ventilation, with driving pressures set to achieve a tidal volume of 6 mL/kg of predicted body weight, an inspiratory time of 1 second, PEEP of 13 cm H2O, and minimum respiratory rate to maintain PaCO2 between 35 and 45 mm Hg.
The “moderate strategy” consisted of three 30-second inflations under continuous positive airway pressure mode at 20 cm H2O and FIO2 of 0.60. Between and after inflations, patients received assist or control volume-controlled ventilation (decelerating-flow waveform), tidal volume of 6 mL/kg of predicted body weight, inspiratory time of 1 second, PEEP of 8 cm H2O, and FIO2 of 0.60, at a minimum respiratory rate that maintained PaCO2 at 35-45 mm Hg.
“[The] use of an intensive alveolar recruitment strategy compared with a moderate recruitment strategy resulted in less severe pulmonary complications during the hospital stay,” the investigators wrote. On average, intensively managed patients had shorter stays in the hospital (10.9 vs. 12.4 days; P = .04) and in the intensive care unit (3.8 vs. 4.8 days; P = .01) than did moderately managed patients. Intensive management also was associated with lower rates of hospital mortality and barotrauma, but the differences in these less common outcomes did not reach statistical significance.
“To our knowledge, this is the first study to show a significant effect of lung recruitment maneuvers on clinical outcomes, which objectively resulted in modest reductions in ICU and hospital length of stay,” the researchers wrote. “This is especially noteworthy considering that the control group was also receiving protective lung ventilation with low [tidal volume] and moderate PEEP levels. Thus, the major difference between treatment groups was the intensity of lung recruitment.”
FAPESP (Fundação de Amparo e Pesquisa do Estado de São Paulo) and FINEP (Financiadora de Estudos e Projetos) provided partial funding. Dr. Leme had no disclosures. Senior author Marcelo Britto Passos Amato, MD, PhD, disclosed research funding from Covidien/Medtronics, Dixtal Biomedica Ltd, and Timpel SA.