Intra-operative adherence to lung-protective ventilation: a prospective observational study.
BACKGROUND
Lung-protective ventilation in patients with acute respiratory distress syndrome improves mortality. Adopting this strategy in the perioperative period has been shown to reduce lung inflammation and postoperative pulmonary and non-pulmonary sepsis complications in patients undergoing major abdominal surgery. We conducted a prospective observational study into the intra-operative ventilation practice across the West Midlands to assess the use of lung-protective ventilation.


METHODS
Data was collected from all adult ventilated patients undergoing surgery across 14 hospital trusts in the West Midlands over a 2-day period in November 2013. Data collected included surgical specialty, patient's biometric data, duration of procedure, grade of anesthetist, and ventilatory parameters. Lung-protective ventilation was defined as the delivery of a tidal volume between 6 and 8 ml/kg/predicted body weight, a peak pressure of less than 30 cmH2O, and the use of positive end expiratory pressure of 6-8 cmH2O. Categorical data are presented descriptively, while non-parametric data are displayed as medians with statistical tests from Mann-Whitney U tests or Kruskal-Wallis tests for independent samples while paired samples are represented by Wilcoxon signed rank tests.


RESULTS
Four hundred six patients with a median age of 56 years (16-91) were included. The majority of operations (78 %) were elective procedures with the principal anesthetist being a consultant. The commonest surgical specialties were general (29 %), trauma and orthopedic (19 %), and ENT (17 %). Volume-controlled ventilation was the preferred ventilation strategy in 70 % of cases. No patients were ventilated using lung-protective ventilation. Overall peak airway pressure (pPeak) was low (median 20 cmH2O (inter-quartile range [IQR] 10-43 cmH2O)) with median delivered tidal volumes of 8.4 ml/kg/predicted body weight (PBW) (IQR 3.5-14.5 ml/kg/PBW). The median positive end expiratory pressure (PEEP) was only 4 cmH2O (0-5 cmH2O) with PEEP not used in 152 cases.


CONCLUSIONS
Perioperative lung protection ventilation can improve patient outcomes from major surgery. This large prospective study demonstrates that within the West Midlands lung-protective ventilation during the perioperative period is uncommon, especially in relation to the use of PEEP, and that perhaps further trials are required to promote wider adoption of practice.
Institute of Inflammation and Ageing, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK.
Jaimin M
JM
Patel
Department of Anaesthesia, University Hospital Birmingham NHS Foundation Trust, Birmingham, UK.
Roisin
R
Baker
Institute of Inflammation and Ageing, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK.
Joyce
J
Yeung
Department of Anaesthesia, University Hospital Birmingham NHS Foundation Trust, Birmingham, UK.
Charlotte
C
Small