Determining optimal cardiac preload during resuscitation using measurements of ventricular compliance.
BACKGROUND
While the right ventricular end-diastolic volume index (RVEDVI) has been shown to be a better indicator of preload than cardiac filling pressures, optimal values during resuscitation from trauma are unknown. This study examines right ventricular stiffness as a guide to optimal values of RVEDVI.


METHODS
Prospective study of 19 critically injured patients monitored with a volumetric pulmonary artery catheter during resuscitation. Per resuscitation protocol, the target RVEDVI was > or = 120 mL/m2. Sequential fluid boluses of 500 to 1000 mL were administered to obtain at least four values of RVEDVI and right ventricular end-diastolic pressure (estimated by central venous pressure [CVP]). For each patient, nonlinear regression was used to construct the ventricular compliance curve based on the equation, CVP = aek(RVEDVI), where k is the coefficient of chamber stiffness.


RESULTS
Overall, the derived compliance curves had excellent fit with the theoretical equation (mean R2, 0.95 +/- 0.04). Mean k was 0.043 +/- 0.012 (range, 0.029-0.067). For each patient, mean RVEDVI during resuscitation was significantly correlated with k (R2 = 0.75, p < 10-5) indicating that chamber stiffness, measured during initial fluid administration, may be used to determine RVEDVI during the ensuing resuscitation.


CONCLUSIONS
In critically injured patients, bedside assessment of right ventricular compliance is possible and may help determine optimal values of RVEDVI during resuscitation.
Kincaid
E H
EH
Department of General Surgery, Wake Forest University School of Medicine, Medical Center Boulevard, Winston-Salem, North Carolina 27157, USA.
Meredith
J W
JW
Chang
M C
MC
D000328:Adult; D000704:Analysis of Variance; D001784:Blood Gas Analysis; D002496:Central Venous Pressure; D002985:Clinical Protocols; D003187:Compliance; D003971:Diastole; D005260:Female; D005440:Fluid Therapy / Q000379:methods; D015600:Glasgow Coma Scale; D006801:Humans; D015601:Injury Severity Score; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000379:methods*; D009104:Multiple Trauma / Q000145:classification / Q000150:complications* / Q000401:mortality; D017711:Nonlinear Dynamics; D019095:Point-of-Care Systems; D011446:Prospective Studies; D011669:Pulmonary Wedge Pressure; D012044:Regression Analysis; D012151:Resuscitation / Q000379:methods; D012769:Shock / Q000145:classification / Q000150:complications* / Q000401:mortality; D013318:Stroke Volume; D016019:Survival Analysis; D018497:Ventricular Dysfunction, Right / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology*