Comparison of the acute hemodynamic effects of hypertonic or colloid infusions immediately after mitral valve repair.

OBJECTIVE: To determine the acute hemodynamic effect of hypertonic saline and/or colloid solutions as volume resuscitation in postoperative mitral valve repair patients. DESIGN: Prospective, randomized trial. SETTING: Postoperative cardiac intensive care unit of Broussais Hospital. PATIENTS: Twenty-six patients who underwent mitral valve repair were prospectively studied. Two patients were excluded during the study. INTERVENTIONS: During the immediate postoperative period, when wedge pressure decreases to <8 mm Hg, patients were randomly assigned to receive 250 mL of either hypertonic saline 7.2%-hydroxyethyl starch 6% (molecular weight, 200,000; hydroxyethylation ratio, 0.5) solution (HS-HES group), hypertonic saline 7.2% solution (HS group), or hydroxyethyl starch 6% solution (HES group). The infusion was completed within 15 mins. No additional volume was infused throughout the study. MEASUREMENTS AND MAIN RESULTS: Standard hemodynamic measurements and echocardiographic data demonstrated that HS-HES and HS induced a higher increase in left ventricular end-diastolic area than HES. In the HS-HES and HS groups, systemic vascular resistances decreased significantly and end-systolic area tended to decrease. In the HES group, systemic vascular resistances did not change and end-systolic area tended to increase. Accordingly, ejection fraction increased significantly by 21% and 18% with HS-HES (from 50.5 +/- 5.5 to 61.2 +/- 4.8) and HS (from 49.7 +/- 3.6 to 58.8 +/- 3.3), respectively, and did not change with HES. A major increase in cardiac index was observed after hypertonic solutions infusion, from 2.9 +/- 0.3 to 4.1 +/- 0.4 L/min/m2 in the HS-HES group and from 2.7 +/- 0.3 to 3.8 +/- 0.4 L/min/m2 in the HS group. Then, cardiac index progressively returned to baseline values within the 3 hrs after the infusion. No significant difference was observed between HS-HES and HS. In these groups, plasma sodium increased significantly after the infusion and remained higher than baseline values throughout the study. Adverse events were observed only with hypertonic solution administration: hypotensive episodes, sudden increases in pulmonary capillary wedge pressure, and ventricular arrhythmias. These side effects are likely attributable to a too-high dose and/or rate of infusion. All patients included in the study were discharged from the hospital before the 10th postoperative day. CONCLUSION: We conclude that in patients who have undergone mitral valve repair, postoperative infusion of hypertonic saline solutions increases left ventricular preload and left ventricular ejection fraction. The use of these hypertonic solutions may be of interest in patients with valvular cardiomyopathy. A titrated dose and a low rate of infusion may substantially improve the safety.

The effects of pethidine, fentanyl and lignocaine on postanaesthetic shivering.

Pethidine is reported to be more effective than equi-analgesic doses of other opioids as an inhibitor of postanaesthetic shivering. The aim of this study was to verify whether this action resulted from a local anaesthetic effect of pethidine or from inadequate fentanyl dosage in previous studies. We studied 52 ASA 1 or 2 patients. They were randomly allocated, in a double-blind fashion, to one of four groups to receive either pethidine (0.85 mg.kg-1) or fentanyl (1.7 micrograms.kg-1) or lignocaine (1 mg.kg-1) or 0.9% saline. All the patients were shivering and had a core temperature below 36 degrees C during recovery from non-septic abdominal or orthopaedic surgery. After 15 min, all the patients given saline were still shivering, as were 92% in the lignocaine group. In contrast, only 23% of the patients who were given fentanyl still shivered (p < 0.01 versus saline) and 8% in the pethidine group (p < 0.001 versus saline). The mean (SD) core temperature in the pethidine group was slightly lower than that in the fentanyl group (35.1 (0.6) and 35.9 (0.5)) when the patients stopped shivering. Furthermore, shivering restarted in 6/10 patients in the fentanyl group after 15 min compared with 1/12 in the pethidine group. Our results show that fentanyl (1.7 micrograms.kg-1) can inhibit postanaesthetic shivering but this effect is less pronounced and of shorter duration than with pethidine (0.85 mg.kg-1).

Incidence of tricuspid regurgitation and vena caval backward flow in mechanically ventilated patients. A color Doppler and contrast echocardiographic study.

In 40 patients requiring mechanical ventilation for an episode of respiratory failure of various causes, prevalence of tricuspid regurgitation (TR) or other cause of vena caval backward flow (VCBF) was systematically investigated using transthoracic Doppler echocardiography. Quantification of TR was obtained from planimetry of the regurgitant jet during color Doppler examination. The influence of cyclic mechanical lung inflation was examined by contrast echography of the inferior vena cava and hepatic veins. All the 40 patients studied had TR, which was mild in 21, moderate in 9 and severe in 10. Using a planimetric scale, TR was more marked during mechanical ventilation, when compared with a brief period of spontaneous breathing. Moreover, contrast echocardiography demonstrated that systolic TR reached inferior vena cava and hepatic veins in 16 cases, and also evidenced direct mechanical action of lung inflation producing a pancardiac VCBF in 15 cases. This high incidence of TR and VCBF partially may explain the relatively poor reliability of the thermodilution method for measurement of cardiac output when used in ventilated patients.

Equivalence of postoperative analgesia with patient-controlled intravenous or epidural alfentanil.

The analgesia and the frequency and severity of oxyhemoglobin desaturation related to alfentanil administration were compared in 32 patients randomly selected to receive patient-controlled analgesia (PCA) by either the epidural (EPI) or intravenous (i.v.) route for a mean period of 16 h after major abdominal surgery. Bolus increments of 250 micrograms of alfentanil with a lockout interval of 5 min for i.v. and of 10 min for EPI route were administered by a programmable pump. Oxygen saturation (SpO2) was monitored for 16 h, using a pulse oximeter; data were collected continuously and stored every 30 s via an interface connected to a computer. For the purpose of analysis, SpO2 was divided into six categories: 95%-100%, 90%-94%, 85%-89%, 80%-84%, 75%-79%, and 70%-74%. Both routes provided similar degrees of analgesia at rest and on coughing. Maximum pain relief was obtained earlier in the i.v. group (P < 0.01). The total consumption of alfentanil was 13,141 +/- 3471 micrograms (mean +/- SD) in the i.v. group and 8000 +/- 4213 micrograms in the EPI group (P < 0.001). The effects on SpO2 were not statistically different between the two groups. Cumulative time spent in each saturation category was similar for the EPI and i.v. groups. Severe desaturation episodes, defined as SpO2 < or = 85% for at least 60 s, occurred in 69% of patients in the EPI group and 56% in the i.v. group.(ABSTRACT TRUNCATED AT 250 WORDS)