Pharmacokinetic-based total intravenous anaesthesia using remifentanil and propofol for surgical myocardial revascularization.

BACKGROUND AND OBJECTIVE: We investigated the following aspects of pharmacokinetic-guided total intravenous anaesthesia with remifentanil and propofol in patients undergoing surgical myocardial revascularization: anaesthetic efficacy, haemodynamic effects, impact on extubation of the trachea and analgesia after operation. METHODS: Thirty-two patients undergoing on-pump coronary bypass surgery received intravenous anaesthesia with remifentanil and propofol. Both drugs were dosed and titrated based on computer-assisted pharmacokinetic models to maintain constant plasma concentrations. The propofol target plasma concentration was 1.2 microg mL(-1) throughout the procedure. A remifentanil target plasma concentration of 8 ng mL(-1) was achieved over 2 min for induction. After tracheal intubation, the opioid plasma concentration was reduced to 4 ng mL(-1), and then titrated up to 8 ng mL(-1) during surgery. Postoperative analgesia was managed with remifentanil infusion until 4 h after tracheal extubation, and a continuous infusion of tramadol was started 1 h before the remifentanil was stopped. RESULTS: After induction of anaesthesia, heart rate (-20%) and cardiac index (-6%) decreased significantly. No hypotensive episodes (mean arterial pressure < 60 mmHg) occurred. Intraoperative haemodynamics were stable. Three cases of myocardial ischaemia were detected: two by transoesophageal echocardiography and one with ST-segment monitoring. The duration of postoperative mechanical ventilation of the lungs was 95 +/- 13 min and the time to extubation was 150 +/- 18 min. Postoperative analgesia was satisfactory in all patients. CONCLUSIONS: Pharmacokinetic-based total intravenous anaesthesia with remifentanil and propofol provides adequate anaesthesia during coronary surgery with cardiopulmonary bypass and allows safe early extubation after operation.

Automated protamine dose assay in heparin reversal management after cardiopulmonary by pass.

BACKGROUND: To evaluate the impact of automated Protamine Dose Assay (PDA) performed with Hemochron 8000 (International Technodyne Company, Edison, NJ) on the management of heparin reversal after cardiopulmonary bypass (CPB). PDA was compared with empirical protamine to heparin ratio with regard to calculation of the protamine dose, and the sensitivity of PDA and ACT to residual circulating heparin after protamine administration was investigated too. DESIGN: prospective and randomized study. SETTING: cardiac surgical center of a General Hospital. PARTICIPANTS: 50 patients undergoing elective cardiac surgery with CPB. INTERVENTIONS: after CPB patients randomly received protamine according to our standard empirical ratio of 1 mg. protamine/100 U. heparin (group S, 24 patients), or to PDA result (group T, 26 patients) based on protamine titration method of determining circulating heparin. After protamine administration ACT and PDA were performed to assess heparin reversal and detect residual circulating heparin. Based on the PDA result, additional protamine was administered in both groups when required. MEASUREMENTS: in both groups basal and post-heparin ACT values, protamine doses, ACT and PDA after protamine administration were measured. RESULTS: The protamine dose was significantly lower (30%) in patients treated according to PDA. In 20% of patients showing normal ACT PDA revealed still circulating heparin, and additional protamine was required. In all other cases ACT and PDA both confirmed heparin reversal. CONCLUSIONS: PDA allowed us to administer a significantly lower amount of protamine. This can reduce incidence of adverse effects of over- and under-infusion of protamine. PDA also proved to be more sensitive than ACT in detecting residual circulating heparin after protamine administration.

[The formation and application of a protocol for postoperative nutrition]. / Costruzione ed applicazione di un protocollo sull'alimentazione postoperatoria.

The experience of development of a protocol for the nutritional management of postoperative surgical patients is described. The protocol was developed with the involvement of all the professionals working in the ward (nurses, anesthetists, dieticians and surgeons). It contained indications on how and when re-start feeding for non complicated surgical patients. Specific indications for diabetic, hypertensive and nephropatic patients were devised. The protocol was readily adopted and successfully implemented, indicating that the strategy of sharing and discussing problems involving all the professionals leads to a better chance of success.

[Post-traumatic constrictive pericarditis with fast course]. / Péricardite constrictive posttraumatique à évolution rapide.

A case is reported of a 46-year-old male patient who sustained a blunt thoracic injury with an anterior flail chest, and right haemopneumothorax. He was intubated and ventilated because of acute respiratory failure. There were initially no signs suggesting any myocardial injury. It was not before day 20 that the electrocardiogram showed a QS wave in leads V2 and V3. The hypothesis of an antero-septal myocardial infarct was not confirmed by echocardiography, which only revealed slight thickening of the posterior pericardium. From day 50 on, the patient had tachycardia, raised jugular venous pressure, and effort dyspnoea. Echocardiography (day 59) showed an anterior and posterior pericardial effusion (about 500 ml), marked pericardial thickening, and inferior vena caval collapse during inspiration, with normal myocardial wall movements. Drainage pericardiocentesis was therefore carried out, followed by, four days later, a pericardiectomy. A small ecchymosis was found on the anterior aspect of the right ventricle. The pericardium was thickened, fibrous, hyperhaemic, Case is y stuck to the epicardium. Eight months later, echocardiography showed that the posterior pericardium remained thickened, and there was a very small residual effusion. Movements of the septum had returned to normal.

[Effects of nifedipine in patients with chronic obstructive bronchitis and pulmonary hypertension undergoing artificial respiration]. / Effets de la nifédipine chez les bronchitiques chroniques obstructifs avec hypertension pulmonaire soumis à la ventilation artificielle.

During an acute decompensation of chronic obstructive pulmonary disease (COPD) associated with pulmonary arterial hypertension (PAHP), the right cardiac ventricle is unable to tolerate the increased workload required to overcome the increase in pulmonary arterial pressure (Ppa). As a result, the cardiac (CI) and systolic (SI) indices decrease much more than in those patients without PAHP. This study aimed to evaluate the effects of nifedipine on haemodynamic parameters and oxygen availability (QO2) when given to mechanically ventilated COPD patients with PAHP during an acute decompensation. The series included 14 patients aged 68 +/- 8 yr, admitted to an intensive care ward for an acute decompensation of COPD, with Ppa greater than 20 mmHg. They remained haemodynamically stable throughout the study period. The measurements were made 20 min after the Swan-Ganz and radial artery catheters were set up (t0), and one hour after administration of 10 mg sublingual nifedipine (t1). Thereafter this agent was given three times a day. A further set of measurements were carried out in seven patients, 24 h after the first dose of nifedipine (t2). At t1, there was a significant increase in CI (+12.3%) and QO2 (+14.1%), whereas Ppa, indexed pulmonary vascular resistances, indexed systemic vascular resistances (SVRI) and PaO2 decreased significantly (-9.2%; -20%; -12.8% and -6.4% respectively). At t2, QO2 was significantly higher (+18.4%), whereas Ppa and SVRI were significantly lower, than at t0. PaO2 and the shunt fraction (Qs/Qt) returned to basal values, with a significant decrease in Qs/Qt when compared with t1.(ABSTRACT TRUNCATED AT 250 WORDS)

[Bronchial stenosis of vascular origin in pulmonary arterial hypertension]. / Sténose bronchique d'origine vasculaire en cours d'hypertension artérielle pulmonaire.

A case is reported of bronchial stenosis due to a vascular cause in a patient with chronic obstructive lung disease, cor pulmonale and pulmonary arterial hypertension. This led to right lower lobe atelectasis and acute respiratory failure (pHa 7.24; PaCO2 85 mmHg; PaO2 44 mmHg) with important right-to-left shunting. This diagnosis was only suggested on day 7 by fibreoptic bronchoscopy and confirmed a week later by tomography and digital angiography. Nifedipine, used to reduce the pulmonary arterial hypertension, increased the cardiac index (31.min-1.m-2 to 3.3.1.min-1.m-2) and oxygen transport (488 ml.min-1.m-2 to 554 ml.min-1.m-2), despite increasing the shunt effect (Qs/QT: 26% to 31%). This and the antiinflammatory action of methylprednisolone were probably responsible for the favourable outcome.

[Mediastinal infusion by a multilumen central venous catheter]. / Perfusion médiastinale par cathéter veineux central multiperforé.

A case of mediastinal perfusion by a left internal jugular vein catheter is reported. The catheter was of Shaldon type with six lateral side-holes. The patient displayed progressive pulmonary oedema and peripheral vasoconstriction, whereas clinically the catheter seemed to work quite well. Only radiological control with injection of radiopaque dye demonstrated mediastinal penetration of the catheter tip including the most distal side-hole. The five more proximally located holes remained in intravascular position. The authors advocate radiographic catheter control with radiopaque dye in every catheterized patient demonstrating cardiorespiratory manifestations of unknown origin.

[Changes in plasma ionized calcium levels during fluorescein angiography]. / Variation du calcium ionisé plasmatique au cours de l'angiographie en fluorescence.

The authors have demonstrated a significant decrease of the plasmatic ionized calcium level in 84 patients during retinal fluorangiography likely due to a chemical bond between calcium and fluorescein. The side effects noticed during the procedure were similar to that quoted in the literature; their frequency, however, was not correlated with the decrease of the plasmatic ionized calcium level, even though the magnitude of the decrease was twice as great in the patients who experienced some trouble as in those who did not. This lack of correlation may be related to the too small patients sample. A greater frequency of side effects has been noticed in patients treated by calcium inhibitors.