EFFECTS OF HYPERTONIC SALINE AND DEXTRAN-70 ON CARDIAC FUNCTIONS AFTER BURNS

The effects of hypertonic saline-dextran (HSD) on cardiac contractilit y and hemodynamics after burns were studied in anesthetized animals wi th full-thickness 50% total body surface area burns that were resuscit ated with HSD or lactated Ringer solution (LR) alone. No significant d ifference in cardiac contractility during 6 h postburn was observed be tween the two groups, as assessed by the end-systolic pressure-volume relationship and the stroke work-end-diastolic volume relationship. An additional bolus of HSD at 6 h postburn caused no significant changes in the end-systolic pressure-volume relationship and stroke work-end- diastolic volume relationship in the burned and sham-burned animals, b oth of which were resuscitated with HSD. Ten minutes of hemodynamic ch anges following HSD infusion at 30 min postburn revealed a sudden incr ease in stroke volume with biphasic responses in left ventricular syst olic pressure, which first decreased, then increased, and finally retu rned to the pre-HSD value. End-diastolic volume was maintained at simi lar to 110% of the pre-HSD value during this period. We concluded that HSD does not enhance cardiac contractility after severe burns but doe s produce direct effects on postburn circulation to reduce afterload a nd augment preload, resulting in a short-lived increase in cardiac out put.