Individualized PEEP to optimise respiratory mechanics during abdominal surgery: a pilot randomised controlled trial. (September 2020)

• Record Type: Journal Article
• Authors: Fernandez-Bustamante, Ana; Sprung, Juraj; Parker, Robert A.; Bartels, Karsten; Weingarten, Toby N.; Kosour, Carolina; Thompson, B. Taylor; Vidal Melo, Marcos F.
• Is Part Of: British journal of anaesthesia. Volume 125:Number 3(2020)
• Page Start: 383
• Page End: 392
• Publication Date: 2020-09
• Subjects: lung compliance -- mechanical ventilation -- positive end-expiratory pressure -- postoperative pulmonary complications -- respiratory mechanics -- ventilator-induced lung injury; Anesthesiology -- Periodicals; Anesthesia -- Periodicals; 617.9605
• DOI: 10.1016/j.bja.2020.06.030
• Languages: English
• ISSNs: 0007-0912

Abstract

Abstract: Background: Higher intraoperative driving pressures (ΔP) are associated with increased postoperative pulmonary complications (PPC). We hypothesised that dynamic adjustment of PEEP throughout abdominal surgery reduces ΔP, maintains positive end-expiratory transpulmonary pressures (Ptp_ee ) and increases respiratory system static compliance (Crs ) with PEEP levels that are variable between and within patients. Methods: In a prospective multicentre pilot study, adults at moderate/high risk for PPC undergoing elective abdominal surgery were randomised to one of three ventilation protocols: (1) PEEP≤2 cm H2 O, compared with periodic recruitment manoeuvres followed by individualised PEEP to either optimise respiratory system compliance (PEEPmaxCrs ) or maintain positive end-expiratory transpulmonary pressure (PEEPPtp_ee ). The composite primary outcome included intraoperative ΔP, Ptp_ee, Crs, and PEEP values (median (interquartile range) and coefficients of variation [CVPEEP ]). Results: Thirty-seven patients (48.6% female; age range: 47–73 yr) were assigned to control (PEEP≤2 cm H2 O; n =13), PEEPmaxCrs ( n =16), or PEEPPtp_ee ( n =8) groups. The PEEPPtp_ee intervention could not be delivered in two patients. Subjects assigned to PEEPmaxCrs had lower ΔP (median8 cm H2 O [7–10]), compared with the control group (12 cm H2 O [10–15]; P =0.006). PEEPmaxCrs was also associated with higher Ptp_ee (2.0 cm H2 O [-0.7 to 4.5] vs controls: -8.3 cm H2 O [-13.0 to -4.0]; P ≤0.001) and higher Crs (47.7 ml cm H2 O [43.2–68.8] vs controls: 39.0 ml cm H2 O [32.9–43.4]; P =0.009). Individualised PEEP (PEEPmaxCrs and PEEPPtp_ee combined) varied widely (median: 10 cm H2 O [8-15]; CVPEEP =0.24 [0.14–0.35]), both between, and within, subjects throughout surgery. Conclusions: This pilot study suggests that individualised PEEP management strategies applied during abdominal surgery reduce driving pressure, maintain positive Ptp_ee and increase static compliance. The wide range of PEEP observed suggests that an individualised approach is required to optimise respiratory mechanics during abdominal surgery. Clinical trial registration: NCT02671721.