We compared the toxicity of systemic local anesthetics bupivacaine and ropivacaine administered at equivalent and equipotent doses. In the first experiments, 18 male Wistar rats were anesthetized with thiopental and maintained under positive controlled ventilation. Electrocardiogram, electroencephalogram, and invasive arterial blood pressure were continuously recorded. The animals were randomly assigned to receive 3 mg x kg(-1) x min(-1) bupivacaine, 3 mg x kg(-1) x min(-1) ropivacaine IV (equivalent group), or 4.5 mg x kg(-1) x min(-1) ropivacaine (equipotent group). The timing of the occurrence of local anesthetic-induced toxic events (defined as the first QRS modification, dysrhythmia, seizures, moderate and severe bradycardia and hypotension, final systole) was recorded and the dose calculated. Eighteen additional rats, treated according to the same protocol were killed at the time of moderate, severe, and final hypotension for blood sampling and plasma bupivacaine and ropivacaine concentration measurement. In a third experiment, 15 awake rats (5 per group) received IV bupivacaine or ropivacaine (same infusion as in the first experiments) until seizure. At this moment, rats were allowed to recover from local anesthetic intoxication. In the first experiment, except for the first QRS modification, all the other toxic manifestations occurred at significantly larger doses (P<0.05) in the two ropivacaine groups in comparison to the bupivacaine group. In awake rats, all the animals intoxicated by ropivacaine easily recovered. In the bupivacaine group, two animals required cardiopulmonary resuscitation before any seizure activity could be detected, and only three rats survived. We conclude that, in the model used, ropivacaine, even at an equipotent dose, is less toxic than bupivacaine.

No abstract

Each year, more than 312 million major surgical procedures are performed worldwide, 1 and the 30-day post-operative death rate is estimated to range between 3.5% and 6.9%. 2-5 The most common risk factors for post-operative mortality include the patient's condition and age, the type of surgery and perioperative and early postoperative complications. 6,7 Intraoperative hypotension (IOH) has also been identified as a risk factor for major organs dysfunction, 8,9 early mortality 10,11 and other adverse post-operative outcomes. 12-16

In-hospital mortality alone is an incomplete measure of mortality even within 30 days of care. To identify the missing deaths, hospital records need to be linked to data from death certificate. This connection with the national death registry will allow obtaining the rate of in-hospital and out-hospital death.

BACKGROUND In anaesthesiology, little attention has been drawn to the role of anaesthesia nurses as support personnel on quality of care. OBJECTIVES To compare an anaesthesiologist alone (solo anaesthesiologist) with an anaesthesia care team (anaesthesiologist and anaesthesia nurse). DESIGN An observational study. SETTING A single centre study. PARTICIPANTS Anaesthesiologists and anaesthesia nurses. INTERVENTION Anaesthesia performed by solo anaesthesiologists compared with anaesthesia care teams. MAIN OUTCOME MEASURES 30-day postoperative mortality and hospital length of stay. Propensity score matching was performed by logistic regression to adjust for baseline differences between the two groups and pairs of perfectly matched patients were formed. RESULTS Anaesthesia was performed by solo anaesthesiologists in 2832 patients and by an anaesthesia care team in 2842 patients. Matching with 2095 pairs of perfectly matched patients was formed. The two groups were comparable in respect of sex and duration of anaesthesia but differed notably for age, American Society of Anesthesiologists' physical status score and type of surgery. Logistic regression showed a significantly lower 30-day mortality rate for the anaesthesia care teams compared with solo anaesthesiologists (0.76 vs. 1.56%, P ¼ 0.0014). Length of hospital stay was also significantly reduced when an anaesthesia nurse was present (4.9 AE 10.1 vs. 5.6 AE 11.5 days, P ¼ 0.0011). CONCLUSION Anaesthesia given by teams of anaesthesiologists and anaesthesia nurses is associated with decreased 30-day postoperative mortality and shorter length of stay when compared with solo anaesthesiologists. Even without any demonstration of causality, this emphasises the benefits of the anaesthesia care team model. TRIAL REGISTRATION CCB 325201730849.