Tracing best PEEP by applying PEEP as a RAMP

• Published in: Intensive care medicine Vol. 24; no. 8; pp. 821 - 828
• Main Authors: PUNT, C. D, SCHREUDER, J. J, JANSEN, J. R. C, HOEKSEL, S. A. A. P, VERSPRILLE, A
• Format: Journal Article
• Language: English
• Published: Heidelberg Springer 01-08-1998; Berlin Springer Nature B.V
• Subjects: Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; Animals; Biological and medical sciences; Blood Gas Analysis; Cardiac output; Compliance; Disease Models, Animal; Edema; Emergency and intensive respiratory care; Feasibility Studies; Hemodynamics; Intensive care; Intensive care medicine; Lungs; Maneuvers; Medical sciences; Monitoring, Physiologic - methods; Oxygen; Oxygen tension; Oxygenation; Point-of-Care Systems - standards; Positive-Pressure Respiration - methods; Positive-Pressure Respiration - standards; Pulmonary Edema - blood; Pulmonary Edema - therapy; Regression Analysis; Swine; Lung disease; Edema; Oxygen; Intensive care; Respiratory disease; Lung; Artificial ventilation; Experimental study; Positive end expiratory pressure; Vertebrata; Mammalia; Swine; Animal; Controlled mechanical ventilation; Artiodactyla; Hemodynamics; Transport; Ungulata
• ISSN: 0342-4642; 1432-1238
• DOI: 10.1007/s001340050672

The aim of this study was to show the feasibility of a slow, continuously increasing level of positive end-expiratory pressure (PEEP) (ramp manoeuvre) in selecting best PEEP and to evaluate whether best PEEP, as defined by maximal oxygen transport, coincides with best systemic arterial oxygenation or best compliance.
In 11 anaesthetized piglets, PEEP was increased between 0 cmH2O (zero end-expiratory pressure; ZEEP) and 15 cmH2O (PEEP15) with a constant rate of 0.67 cmH2O x min(-1). This ramp manoeuvre was performed both under normal conditions and after induction of an experimental lung oedema. During the ramp manoeuvre, haemodynamic and pulmonary variables were monitored almost continuously.
During the rise in PEEP, cardiac output declined in a non-linear way. In the series with normal conditions, best PEEP was always found at ZEEP. In the series with experimental lung oedema, best PEEP, as defined by maximum oxygen transport, was found at PEEP1-6, as defined by maximal compliance, at PEEP7.5 and by maximal arterial oxygen tension (PaO2) at PEEP10-14.
Best PEEP according to oxygen transport is lower than best PEEP according to compliance and PaO2; the use of PEEP as a ramp might prevent unnecessarily high levels of PEEP.