Right ventricular dysfunction in acute thermal injury

The elevated cardiac output (CO) and pulmonary artery hypertension (PAH) observed in thermal injury offers a unique opportunity to study the effects of a combined pressure-flow load on the right ventricle in previously healthy persons. Potential responses include a diminished right ventricular ejection fraction (RVEF), increased right ventricular end-diastolic volume index (RVEDVI), and augmented myocardial oxygen consumption because of increased systolic wall tension. We investigated these factors in 15 nonhypoxic patients without sepsis having 15--75% body surface area burns using flow directed catheters and the thermodilution technique. All patients increased their CO in response in fluid resuscitation, but six patients with an elevated mean pulmonary artery pressure (greater than 20 mmHG and increased pulmonary vascular resistance (greater than 1.2 mmHg/min/L) had right ventricular dysfunction as evidenced by an increase (188 +/- 15 ml/M2) in RVEDVI and a decreased (0.26 +/- 4 ml/M2) RVEF. Patients without PAH had a smaller RVEDVI (115 +/- 4 ML/M2) and larger RVEF (0.39 +/- 0.02). Patients with PAH and RV dysfunction were older, had larger body surface area burns, lower systemic diastolic artery pressures (63 +/- 4 mmHg) and higher heart rates (114 +/- 7 beats/min); RV end-diastolic pressures were minimally elevated (9.5 +/- 1.4 mmHg). The decrease in RVEF and increase in RVEDVI may limit the hemodynamic response to fluid volume replacement and survival.