Biomedical subjects

Massimo Bertolissi

Publications and source records attributed to Massimo Bertolissi.

3 recordsLinked to original sources

PubMed2003

Influence of passive leg elevation on the right ventricular function in anaesthetized coronary patients.

INTRODUCTION: The aim of the present study was to evaluate the haemodynamic effects of passive leg elevation on the right ventricular function in two groups of patients, one with a normal right ventricular ejection fraction (RVEF) and one with a reduced RVEF. METHODS: Twenty coronary patients undergoing elective coronary artery bypass grafting surgery were studied by a RVEF pulmonary artery catheter. The haemodynamic data reported were collected before the induction of anaesthesia (time point 1), just before (time point 2) and 1 min (time point 3) after the legs were simultaneously raised at 60 degrees, and 1 min after the legs were lowered (time point 4). The patients were divided into two groups: group A, with preinduction RVEF > 45%; and group B, with preinduction RVEF < 40%. RESULTS: In group A (n = 10), at time point 3 compared with time point 2, the heart rate significantly decreased (from 75 +/- 10 to 66 +/- 7 beats/min). The right ventricular end diastolic volume index (from 105 +/- 17 to 133 +/- 29 ml/m2), the right ventricular end systolic volume index (from 61 +/- 13 to 77 +/- 24 ml/m2), the systolic systemic arterial/right ventricular pressure gradient (from 93 +/- 24 to 113 +/- 22 mmHg) and the diastolic systemic arterial/right ventricular pressure gradient (from 58 +/- 11 to 66 +/- 12 mmHg) significantly increased. Also in group A, the cardiac index did not significantly increase (from 3.28 +/- 0.6 to 3.62 +/- 0.6 l/min/m2), the RVEF was unchanged, and the right ventricular end diastolic volume/pressure ratio (RVED V/P) did not significantly decrease (from 48 +/- 26 to 37 +/- 13 ml/mmHg). In group B (n = 6) at the same time, the heart rate (from 72 +/- 15 to 66 +/- 12 beats/min), the right ventricular end diastolic volume index (from 171 +/- 50 to 142 +/- 32 ml/m2) and the RVED V/P (from 71 +/- 24 to 39 +/- 7 ml/mmHg) significantly decreased. The cardiac index and the diastolic systemic arterial/right ventricular pressure gradient were unchanged in group B, while the RVEF and the systolic systemic arterial/right ventricular pressure gradient did not significantly increase, and the right ventricular end-systolic volume index did not significantly decrease. All results are expressed as mean +/- standard deviation. CONCLUSIONS: We conclude that passive leg elevation caused a worse condition in the right ventricle of group B because, with stable values of cardiac index, of systolic systemic arterial/right ventricular pressure gradient and of diastolic systemic arterial/right ventricular pressure gradient (which supply oxygen), the RVED V/P (to which oxygen consumption is inversely related) markedly decreased. This is as opposed to group A, where the cardiac index, the systolic systemic arterial/right ventricular pressure gradient and the diastolic systemic arterial/right ventricular pressure gradient increased, and the RVED V/P slightly decreased. Passive leg elevation must therefore be performed cautiously in coronary patients with a reduced RVEF.

Aged↗

PubMed2002

Pruritus: a useful sign for predicting the haemodynamic changes that occur following administration of vancomycin.

INTRODUCTION: The aim of this study was to investigate the haemodynamic changes that follow the appearance of pruritus during vancomycin administration. METHODS: We studied 50 patients scheduled for coronary artery bypass surgery, and we compared data from patients who exhibited pruritus with those from patients who did not. After the monitoring devices had been positioned, vancomycin (15 mg/kg) was continuously infused at a constant rate over 30 min, before induction of anaesthesia. Haemodynamic profiles were recorded before vancomycin infusion (time point 1); at 15 (time point 2) and 30 min (time point 3) after the beginning of vancomycin infusion; and 15 min after vancomycin infusion had been stopped (time point 4). At each time arterial and mixed venous blood samples were drawn to calculate the shunt fraction (Qsp/Qt). RESULTS: In patients who exhibited pruritus (group A, n = 17) at time point 3 versus time point 1, systemic vascular resistance index (SVRI) and arterial oxygen tension (PaO2) decreased significantly; cardiac index (CI), stroke volume index (SVI) and Qsp/Qt increased significantly; and mean systemic pressure and heart rate were stable. Those changes were observed only in patients not treated with a beta-blocker before surgery, whereas no change occurred in patients treated with the drug. In the patients who were free from pruritus (group B, n = 28), we did not observe any significant change. CONCLUSION: The appearance of pruritus during vancomycin administration indicates that SVRI is declining, thus exposing the patient to risk for hypotension. Therapy with a beta-blocker appears to confer protection against this hemodynamic reaction.

Anti-Bacterial Agents↗

PubMed2002

TDM coupled with Bayesian forecasting should be considered an invaluable tool for optimizing vancomycin daily exposure in unstable critically ill patients.

A randomized two-arm prospective study was planned to assess the role of therapeutic drug monitoring (TDM) coupled with a Bayesian approach in tailoring vancomycin dosages in unstable critically ill patients. Group A (n=16) had their regimen adjusted day-by-day according to TDM and Bayesian forecasting (D(a)); group B (n=16) had their regimen adjusted day-by-day according to Moellering's nomogram (D(M)). Blood samples were collected every 1-2 days to assess the trough and peak plasma concentrations. In group A, the tailored D(a) required for optimizing vancomycin exposure were considerably higher than the D(M) in 7/16 cases, and lower than the D(M) in 1/16 cases. In group B, standard D(M) caused under-treatment in 3/16 cases and over-treatment in 4/16 cases. Most of these patients concomitantly had some conditions that might have altered vancomycin disposition. The TDM-guided Bayesian-based approach should be considered an invaluable tool for clinicians to handle appropriately on real-time vancomycin therapy in critically ill patients.

Adult↗