Ammonia plasma concentration and prolonged infusion of remifentanil in patients with acute kidney injury.

BACKGROUND: Glycine is an excipient of remifentanil and may induce side effects. To investigate glycine and ammonia concentration with the use of remifentanil in Intensive Care Unit patients with acute kidney injury (AKI) defined by a decrease in creatinine clearance above 50%. METHODS: Prospective open-label cohort study in three surgical Intensive Care Units. Thirty-three patients with AKI and requiring sedation for at least 72 hours. Sedation with remifentanil and midazolam or propofol was adapted every six hours according to ATICE. Glycine and ammonia plasma concentrations were measured at H0 (start of infusion) and every 12 hours during a continuous intravenous 72 hours remifentanil infusion, and 24 hours after the end of the infusion. Clinical and biological glycine or ammonia toxicity were evaluated. RESULTS: Fifteen patients required continuous veno-venous hemodiafiltration (CVVHDF). Glycine and ammonia plasma concentrations exceeded the normal value respectively for 11 (33%) and 15 (45%) patients before remifentanil infusion (H0). Accumulation of glycine or ammonia was observed neither for patients with or without CVVHDF. For patients without CVVHDF, the plasma ammonia concentration at the end of remifentanil infusion was significantly correlated with the creatinine clearance at H72 (P=0.03) and with the mean rate of remifentanil infusion (P=0.002). No side effect was reported. CONCLUSION: Remifentanil was not associated with an accumulation of glycine or ammonia in patients with AKI. Plasma ammonia concentration was correlated with the mean rate of remifentanil and creatinine clearance. A 72-hours remifentanil infusion appeared safe for sedation of patients with AKI.

[Withholding or withdrawing of life sustaining therapies in emergency context. Perception by anaesthesiologists]. / Limitation ou arrêt de thérapeutiques actives en situations d'urgence. Le point de vue des anesthésistes réanimateurs.

OBJECTIVES: One objective is to state more accurately the difficulties met by the anaesthesiologists in an emergency context in case of withholding or withdrawing life sustaining therapies. STUDY DESIGN AND PARTICIPANTS: A questionnaire addressed to anaesthesiologists of nine hospitals in the extreme West part of France. MATERIALS AND METHODS: The questionnaires were sent and returned by mail in order to guarantee confidentiality. RESULTS: The participation rate was 40% with 172 questionnaires analysed. Ninety-eight per cent of the anaesthesiologists have already participated in a withholding or withdrawing life sustaining treatments, and in an emergency context in 92% of the cases. In that last case, criteria related to the severity of the clinic presentation and to the short-term death probability influence the decision made to interrupt life-sustaining therapies. For 93% of anaesthesiologists, the decision should be collegial, but 50% of them had already made such a decision alone. The withdrawal of ventilatory support was the most difficult decision to make. Withdrawing mechanical ventilation or extubating appeared impossible for 23.4 and 50% of the anaesthesiologists respectively. Providing comfort care to the patients with end of life decision was essential for 100% of the anaesthesiologists, but 11% of them used and considered analgesic and sedation after withholding or withdrawing life sustaining treatments as euthanasia. The complaint possibility worried 57% of the anaesthesiologists and influenced the writing of the process or giving information to the families respectively for 65 and 75%. The righting of the medical files could be improved for 92% of the anaesthesiologists. CONCLUSION: The decision of withholding and withdrawing life sustaining treatments in an emergency context is based on the conviction of short-term death probability. Withholding and withdrawing life sustaining treatments is a decision made according to the principles of collegiality and necessary comfort cares, but the procedure can still be improved, especially in the redaction of the medical file and the ethical and juridical control of these extreme situations.

Angioscopic video-assisted pulmonary endarterectomy for post-embolic pulmonary hypertension.

OBJECTIVES: To assess whether the use of video-assisted angioscopy would increase the outcome of pulmonary thromboendarterectomy (PTE). METHODS: PTE included a median sternotomy, intrapericardial dissection of the superior vena cava, institution of cardiopulmonary bypass, deep hypothermia and sequential circulatory arrest periods. It was always performed through two separate arteriotomies on both main intrapericardial pulmonary arteries, into which a rigid 5 mm angioscope connected to a video camera was introduced to increase the visibility and endarterectomies. RESULTS: From January 1996 to July 1998, 68 consecutive patients (35 males and 33 females) aged 54.3 +/- 13.5 years underwent PTE. Patients were in New York Heart Association (NYHA) class II (n = 2), III (n = 43) or IV (n = 23) with the following hemodynamics: mean pulmonary arterial pressure (PAP) 54 +/- 13 mmHg; cardiac output (CO): 3.8 +/- 0.8 l/min, and total pulmonary resistance (TPR): 1207 +/- 416 dyne x s x cm(-5). The cumulated circulatory arrest time was 23 +/- 12 min and postoperative length of ventilatory support 10 +/- 12 days. Nine patients died, for an overall in-hospital mortality of 13.2%. The functional outcome in surviving patients was significantly improved (P < 0.0001) both clinically (NYHA class 3.2 +/- 0.5 vs. 1.3 +/- 0.6) and hemodynamically (PAP (mmHg) 53.1 +/- 13 vs. 30.2 +/- 11.8, CI (l/min per m2) 2.1 +/- 0.5 vs. 2.8 +/- 0.6, TPR (dyne x s x cm(-5)) 1174 +/- 416 vs. 519 +/- 250). CONCLUSIONS: Video-assisted angioscopy improves the quality and degree of pulmonary endarterectomy expanding the indications to include patients with previously inaccessible distal disease.

[Pulmonary thromboendarterectomy with video-angioscopy and circulatory arrest: an alternative to cardiopulmonary transplantation and post-embolism pulmonary artery hypertension]. / Thrombo-endartériectomie pulmonaire sous vidéo-angioscopie et arrêt circulatoire: une alternative à la transplantation cardiopulmonaire dans l'hypertension artérielle pulmonaire postembolique.

The best predictor of poor or suboptimum outcome from pulmonary thromboendarterectomy (PTE) is insufficient relief of obstruction, especially in the lower lobes. The aim of this study is to emphasize that the use of video-assisted angioscopy may increase the quality of PTE and thus improve outcome. PTE included a median sternotomy, intrapericardial dissection limited to the superior vena cava, institution of cardiopulmonary bypass, deep hypothermia and sequential circulatory arrest periods. PTE was always bilateral and performed through two separate arteriotomies of both main intrapericardial pulmonary arteries. A rigid 5 mm angioscope connected to a video camera was introduced through the arteriotomy into the lumen to increase the visibility and perform the video-assisted endarterectomies of all obstructed segmental branches, including normally inaccessible anterior segmental branches. Between January 1996 and December 1997, 48 patients with severe postembolic pulmonary hypertension had PTE. Patients were in New York Heart Association (NYHA) class II (n = 2), III (n = 28) or IV (n = 18) with the following hemodynamics: mean pulmonary arterial pressure (PAP) 53 +/- 13 mmHg, cardiac index 2.16 +/- 0.5 L/min/m2, pulmonary vascular resistances (PVR): 1,152 +/- 414 dyne.s-1.cm-5. Six patients died from alveolar hemorrhage (n = 1), high residual pulmonary pressure and rethrombosis (n = 4) and hypoxic cardiac arrest (n = 1). The functional outcome in surviving patients was as follows: (NYHA) class I (n = 24), II (n = 16) or III (n = 2) with improved hemodynamics: mean pulmonary arterial pressure: 30 +/- 9 mmHg, cardiac index: 2.78 +/- 0.5 L/min/m2, pulmonary vascular resistances (PVR): 484 +/- 159 dynes.s-1.cm-5. Video-assisted angioscopy allows much improved quality and degree of pulmonary endarterectomy. This expands the indications to include patients with previously inaccessible distal disease and candidates for heart-lung transplantation.