Non steady state and steady state PKS Bayesian forecasting and vancomycin pharmacokinetics in ICU adult patients.

The pharmacokinetics of vancomycin was investigated in adult ICU patients after the first administration and at steady state. Then the predictive performance of a two-compartment Bayesian forecasting program was assessed in these patients by using population-based parameters and three non steady state vancomycin concentrations as feedback information. Finally a prospective investigation was carried out to search potential covariates. At steady state, a significant decrease (around 30%) in clearance (CL) was observed, while creatinine clearance (CLcr) was stable and a significant increase (around 30%) in volume of distribution (V(SS)) was observed. A two-fold increase in elimination half-life was found. CL was weakly correlated with CLcr at onset of therapy and at steady state. The Bayesian program tended to overpredict vancomycin peak and trough concentrations. A larger mean prediction error and a poorer precision were observed when population-based parameter estimates were used (no feedback) compared to feedback prediction, but the differences were not significant. Mechanical ventilation and concurrent opioid therapy may be pertinent covariates of vancomycin pharmacokinetics. The current work has shown that vancomycin pharmacokinetics in ICU patients displayed a significant variability and a significant change in both clearance and distribution during the course of therapy. Further investigation is necessary to clarify these findings. Moreover, the use of the Bayesian forecasting PKS program in our patients led to a prediction with low bias but rather poor precision. This outcome highlights the need to implement a population modeling approach, to determine the vancomycin pharmacokinetic parameters and covariates in our ICU patients, and to apply this information to provide more accurate concentration predictions.

Capillary refilling time and hemodynamics in neonates: a Doppler echocardiographic evaluation.

OBJECTIVE: To evaluate the correlation of the capillary refilling time measured in neonates with the hemodynamic parameters obtained by Doppler echocardiography. DESIGN: Prospective study. SETTING: Neonatal intensive care unit (ICU) in a university hospital. PATIENTS: Neonates without congenital cardiac disease admitted to the neonatal ICU (n = 100). INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The clinical parameters obtained were: heart rate; blood pressure; mean airway pressure; cutaneous temperature; and capillary refilling time. The echocardiographic data included the measurement of aortic diameter, left atrial diameter, and shortening fraction. Pulsed-Doppler echocardiography was used to measure flow velocity values in the ascending aorta, in the pulmonary artery trunk, and in the patent ductus arteriosus. Cardiac index was calculated secondarily from the volumetric equation, including measured flow velocity in the ascending aorta, aortic diameter, and body weight. Shunt severity at this level was measured by analysis of the descending aortic flow. Thereafter, three groups were defined for analysis: group 1 with obliterated ductus arteriosus; group 2 with patent ductus arteriosus without a retrograde flow in the subdiaphragmatic aorta; and group 3 with patent ductus arteriosus and a retrograde flow in the subdiaphragmatic aorta. There was no correlation between the capillary refilling time and the following parameters: shortening fraction; mean airway pressure; body weight; left atrial diameter/ aortic diameter ratio; blood pressure; and heart rate. In group 1, the capillary refilling time was significantly linked to cardiac index (r2 = .54, p < .001). A lower correlation coefficient between capillary refilling time and cardiac index was found in groups 2 (r2 =.31, p < .001) and 3 (r2 =.41, p < .001). CONCLUSION: The capillary refilling time was significantly linked to cardiac index in neonates.

[Abdominal syndromes and analgesia]. / Syndromes abdominaux et analgésie.

Despite physiological advances and recent progress in pain relief, early analgesia for patients with acute abdominal pain is not a conventional endpoint. In clinical practice, priority is often given to diagnosis and management decisions. There are few controlled trials to settle the issue and opinions are still divided. recent studies suggest than early and effective analgesia in acute abdomen does not interfere with diagnosis, and even facilitates initial examination. Various modes of analgesia can be considered.

[Pain and tourniquet in orthopedic surgery]. / Douleur et garrot pneumatique d'orthopédie.

The use of a pneumatic tourniquet to provide a bloodless field in orthopedic surgery is often complicated by tourniquet pain. The mechanism of this pain remains incompletely understood, but it is probably multifactorial. Nerve compression is a common etiologic feature. The use of local anaesthetics may be considered the best choice for avoiding tourniquet pain. Superficial (skin) compression and deep components compression like blood vessels and muscles can both induce tourniquet pain. Central nervous system can also interfere. Release of tourniquet can increase the pain by post-ischaemic oedema due to ischaemia and reperfusion injury.