A comparative study of preload-adjusted maximal and peak power: assessment of ventricular performance in clinical practice.

This study was performed to determine whether preload-adjusted peak power can act as a surrogate for preload-adjusted maximal power in the assessment of left ventricular performance in the clinical setting. Ninety-nine consecutive patients who had undergone elective coronary artery bypass grafting were studied. Fifty-five of these patients were divided into four study groups. Afterload was changed with phenylephrine (n = 12) or glyceryl trinitrate (n = 13), preload was increased with intravenous colloid (n = 18), and contractility was increased with dobutamine (n = 12). There was excellent correlation between the two indices (r = 0.99, y = 1.0168x + 0.0769; p < 0.0001). Manipulation of neither preload nor afterload affected the indices. Both indices increased significantly during dobutamine infusion (p = 0.002). In conclusion, preload-adjusted peak power can be used as a substitute for preload-adjusted maximal power in the determination of ventricular performance in clinical practice.

Estimation of myocardial performance in CABG patients.

Myocardial performance index (MPI) permits a relative easy estimation of global left ventricular (LV) systolic and diastolic function. It was shown that MPI inversely correlated strongly with the maximum derivative of LV pressure with respect to time (+dP/dtmax). The current study evaluated the change of MPI during and immediately after coronary artery bypass surgery (CABG) surgery and analyzed the relationship between MPI and hydraulic energy (exemplified by preload adjusted maximal power-PAMP) during that same period. The study was conducted in 45 patients undergoing CABG. After induction of anaesthesia, 10 min after revascularization and 2 h postoperatively, haemodynamics were assessed. Preload was characterized by LV end-diastolic area indexed for BSA (LVEDAI); afterload was estimated by arterial elastance (Ea) and indexed systemic vascular resistance (SVRI). Global myocardial performance was indicated in terms of MPI and contractility was achieved by PAMP. Myocardial performance index increased postoperatively (0.44 +/- 0.13, 0.37 +/- 0.17 and 0.50 +/- 0.16, respectively; P < 0.001). Preload adjusted maximal power did not alter significantly (1.90 +/- 1.24, 2.02 +/- 1.34 and 2.12 +/- 1.00 W cm(-2)*10(4), respectively). Left ventricular enddiastolic area indexed did not change. Arterial elastance augmented to 0.76 +/- 0.39, 0.80 +/- 0.40 and 1.01 +/- 0.43 mmHg ml(-1), respectively; P < 0.001. Systemic vascular resistance did not change. A relationship was found between 1-MPI/LVEDAI2 and PAMP (R2 = 0.50). This study shows that in the setting of CABG surgery, MPI appears to be a good measure of global LV function.

Contractility in humans after coronary artery surgery.

BACKGROUND: Propofol's unique pharmacokinetic profile offers advantages for titration and rapid emergence in patients after coronary artery bypass graft (CABG) surgery, but concern for negative inotropic properties potentially limits its use in these patients. The current study analyzed the effect of various propofol plasma concentrations on left ventricular (LV) contractility by means of a single-beat contractile index based on LV maximal power (PWR(max)). METHODS: The study was conducted in 30 patients after CABG surgery. Immediately after admission to the intensive care unit (ICU), four different plasma concentrations of propofol 0.65, 1.30, 1.95, and 2.60 microg/ml were established. At each concentration level, the cardiac and vascular effects of propofol were studied by combining echocardiographic data with invasively derived aortic root pressure. Preload was characterized by LV end-diastolic dimensions. Afterload was indicated in terms of indexed systemic vascular resistance (SVRI), LV end-systolic meridional wall stress (LV-ESWS), and arterial elastance (Ea). Quantification of effects on contractility was achieved by preload-adjusted PWRmax. RESULTS: Myocardial contractility did not change during a fourfold increase in propofol plasma concentration. Preload-adjusted PWRmax amounted to 3.90+/-1.75 W x ml(-2) x 10(4), 3.98+/-1.69, 3.94+/-1.70, and 3.88+/-1.72, respectively (mean+/-SD). With respect to ventricular loading conditions, propofol caused a significant reduction in both pre- and afterload. CONCLUSIONS: The current results strongly suggest that propofol lacks direct cardiac depressant effects. Nevertheless, meaningful vascular actions of propofol could be demonstrated. Significant decreases in ventricular loading conditions accounted for a marked decrease in arterial blood pressure and supported the concept that propofol in clinically relevant concentration is a vasodilator.

Management of candidal thrombophlebitis of the central veins: case report and review.

Candidemia and major organ candidiasis are problems that emerged in the past 2 decades and that are partially due to medical progress. Catheter-related thrombosis of the central veins is known to be a frequent but mostly subclinical complication of central venous lines. Although candidemia and catheter-related thrombosis are frequent, candida thrombophlebitis of the central veins is rarely reported. We recently successfully treated a 19-year-old polytrauma patient with candidal thrombophlebitis of the innominate vein. Despite catheter removal and therapy with amphotericin B, recurrent candidemia and signs of infection persisted, and a complete resection of the involved vein had to be performed. Only 16 well-documented cases of candidal thrombophlebitis of the central veins in adults have been reported over the past 20 years. An analysis of these 16 patients, together with our patient, is made in relation to risk factors, clinical features, diagnosis, therapy, and mortality.