Aprv

Available online http://ccforum.com/content/5/4/221

Research article

Airway pressure release ventilation increases cardiac performance in patients with acute lung injury/adult respiratory distress syndrome
Lewis J Kaplan*†, Heatherlee Bailey† and Vincent Formosa‡
*Medical College of PA-Hahnemann University, Department of Surgery, Philadelphia, Pennsylvania, USA †Department of EmergencyMedicine, Medical College of PA-Hahnemann University, Philadelphia, Pennsylvania, USA ‡Department of Pulmonary Critical Care, Medical College of PA-Hahnemann University, Philadelphia, Pennsylvania, USA

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Correspondence: Lewis J Kaplan, Lewis.Kaplan@drexel.edu

Received: 5 August 1999 Revisions requested: 16 September 1999 Revisions received: 26 January 2001 Accepted: 8 May 2001Published: 3 July 2001

Critical Care 2001, 5:221–226 This article is online at http://ccforum.com/content/5/4/221 © 2001 Kaplan et al, licensee BioMed Central Ltd (Print ISSN 1364-8535; Online ISSN 1466-609X)

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Abstract
Background The purpose of the present study is to determine whether airway pressure release ventilation (APRV) can safely enhance hemodynamics in patients with acutelung injury (ALI) and/or adult respiratory distress syndrome (ARDS), relative to pressure control ventilation (PCV). Methods Patients with severe acute lung injury or ARDS who were managed with inverse-ratio pressure control ventilation, neuromuscular blockade and a pulmonary artery catheter were switched to APRV. Hemodynamic performance, as well as pressor and sedative needs, was assessed afterdiscontinuing neuromuscular blockade Results Mean age was 58 ± 9 years (n = 12) and mean Lung Injury Score was 7.6 ± 2.1. Temperature and arterial oxygen tension/fractional inspired oxygen (FiO2) were similar among the patients. Peak airway pressures fell from 38 ± 3 for PCV to 25 ± 3 cmH2O for APRV, and mean pressures fell from 18 ± 3 for PCV to 12 ± 2 cmH2O for APRV. Paralytic use and sedativeuse were significantly lower with APRV than with PCV. Pressor use decreased substantially with ARPV. Lactate levels remained normal, but decreased on APRV. Cardiac index rose from 3.2 ± 0.4 for PCV to 4.6 ± 0.3 l/min per m2 body surface area (BSA) for APRV, whereas oxygen delivery increased from 997 ± 108 for PCV to 1409 ± 146 ml/min for APRV, and central venous pressure declined from 18 ± 4 forPCV to 12 ± 4 cmH2O for APRV. Urine output increased from 0.83 ± 0.1 for PCV to 0.96 ± 0.12 ml/kg per hour for APRV. Conclusion APRV may be used safely in patients with ALI/ARDS, and decreases the need for paralysis and sedation as compared with PCV-inverse ratio ventilation (IRV). APRV increases cardiac performance, with decreased pressor use and decreased airway pressure, in patients withALI/ARDS.
Keywords acute lung injury, adult respiratory distress syndrome, airway pressure release ventilation, hemodynamics, neuromuscular blockade

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Introduction
The optimal method of ventilating and oxygenating patients with ALI or ARDS remains a hotly debated topic. Recent advances in lung injury research have refocused clinical attention on reduced tidal volumes and limitedpeak airway pressures in order to diminish the impact of gas delivery to lungs with abnormal compliance, volume, and regional time constants [1]. Despite such focus, the benefits of a pressure-limited or volume-limited strategy for ALI remain controversial [2]. From the midst of multiple

meeting abstracts

ABC = arterial blood gas; ALI = acute lung injury; APRV = airway pressure releaseventilation; ARDS = adult respiratory distress syndrome; BIS = bispectral index; BSA = body surface area; CPAP = continuous positive airway pressure; FiO2, fractional inspired oxygen; ICU = intensive care unit; IRV = inverse ratio ventilation; PAC = pulmonary artery catheter; PCV = pressure-controlled ventilation; PEEP = positive end-expiratory pressure; SvO2 = mixed venous oxygen saturation....