Journal Article

Replacement of anesthesia machines improves intraoperative ventilation parameters associated with the development of acute respiratory distress syndrome

Stentz, Michael J, Engoren, Milo, Davila, Victor, Blum, James M, Dechert, Ronald, Jewell, Elizabeth

2014

Overview

Background The impact of anesthetic equipment on clinical practice parameters associated with development of acute respiratory distress syndrome (ARDS) has not been extensively studied. We hypothesized a change in anesthesia machines would be associated with parameters associated with lower rates of ARDS. Methods We performed a retrospective cohort study on a subset of data used to evaluate intraoperative ventilation. Patients included adults receiving a non-cardiac, non-thoracic, non-transplant, non-trauma, general anesthetic between 2/1/05, and 3/31/09 at the University of Michigan. Existing anesthesia machines (Narkomed IIb, Drager) were exchanged for new equipment (Aisys, General Electric). The initial subset compared the characteristics of patients anesthetized between 12/1/06 and 1/31/07 (pre) with those between 4/1/07 and 5/30/07 (post). An extended subset examined cases two years pre and post exchange. Using the standard predicted body weight (PBW), we calculated and compared the tidal volume (total Vt and mL/kg PBW) as well as positive end-expiratory pressure (PEEP), peak inspiratory pressure (PIP), Delta P (PIP-PEEP), and FiO2. Results A total of 1,414 patients were included in the 2-month pre group and 1,635 patients included in the post group. Comparison of ventilation characteristics found statistically significant differences in median (pre v post): PIP (26 ± 6 v 21 ± 6 cmH2O,p < .001), Delta P (24 ± 6 v 19 ± 6 cmH2O, p < .001), Vt (588 ± 139 v 562 ± 121 ml, p < 0.001; 9.3 ± 2.2 v 9.0 ± 1.9 ml/kg predicted body weight, p < .001), FiO2 (0.57 ± 0.17 v 0.52 ± 0.18, p < .001). Groups did not differ in age, ASA category, PBW, or BMI. The two year subgroup had similar parameters. Risk adjustment resulted in minimal differences in the analysis. New anesthesia machines were associated with a non-statistically significant reduction in postoperative ARDS. Conclusions In this study, a change in ventilator management was associated with an anesthesia machine exchange. The smaller Vt and lower PIP noted in the post group may imply a lower risk of volutrauma and barotrauma, which may be significant in at-risk populations. However, there was not a statistically significant reduction in the incidence of post-operative ARDS.

• Publisher: BioMed Central,BioMed Central Ltd,Springer Nature B.V
• Subject: Adult / Aged / Analysis / Anesthesia / Anesthesia - methods / Anesthesiology / Anesthesiology - instrumentation / Blood Gas Analysis / Body weight / Chronic obstructive pulmonary disease / Cohort Studies / Colleges & universities / Compliance / Critical care / Critical Care Medicine / Electrical equipment and supplies industry / Emergency Medicine / Female / Gas flow / Gases / Health aspects / Hospitals / Humans / Information management / Intensive / Internal Medicine / Intraoperative Care - methods / Male / Medical personnel / Medicine / Medicine & Public Health / Microcomputers / Middle Aged / Mortality / Patients / Prospective Studies / Research Article / Respiration, Artificial - instrumentation / Respiratory diseases / Respiratory distress syndrome / Respiratory Distress Syndrome, Adult - physiopathology / Respiratory Distress Syndrome, Adult - therapy / Retrospective Studies / Review boards / Tidal Volume / Ventilation