Levobupivacaine versus racemic bupivacaine for spinal anaesthesia in orthopaedic major surgery.

AIM: Levobupivacaine, a new local anaesthetic, has been recently introduced into clinical practice because of its lower toxic effects for heart and central nervous system. It has been already investigated in epidural and loco-regional techniques, but more has to be known regarding its characteristics in spinal anaesthesia. The aim of our study was to compare clinical and anaesthetic features of levobupivacaine and racemic bupivacaine when intrathecally administered in 60 patients undergoing major orthopaedic surgical procedures. METHODS: Three ml of glucose-free levobupivacaine 0.5% (group L) or 3 ml of isobaric bupivacaine 0.5% (group B) were administered in 30 patients each. Sensory and motor blockades were evaluated by the pinprick test and a modified Bromage score, respectively. Vital parameters, postoperative VAS and rescue analgesia were recorded as well. RESULTS: No statistically significant differences between groups were observed either in anaesthetic potencies or postoperative pain. Either heart rate or mean arterial pressure slightly decreased in both groups, with no preoperative significant differences. Nevertheless, spinal puncture was accompanied by severe hypotension and bradycardia in 2 patients of group B. In both cases, hemodynamics were promptly and successfully treated, with no sequelae. CONCLUSIONS: In conclusion, levobupivacaine results a valid alternative to racemic bupivacaine for spinal anaesthesia, the latter remaining a cheap and effective local anaesthetic yet. Notwithstanding the complete absence of any significant hemodynamic complications in the patients of group L, further and larger studies are needed in order to assess if levobupivacaine is preferable to bupivacaine for minimizing the possible cardiovascular impact of spinal anaesthesia.

Effects of remifentanil on human heart electrical system. A transesophageal pacing electrophysiological study.

AIM: Previous studies have shown that the administration of remifentanil (a micro-agonist opioid) is often accompanied by bradyarrhythmias preventable or manageable by parasympatholytic drugs. The aim of this paper is to evaluate if these negative chronotropic effects are exclusively due to an increased parasympathetic activity or to a direct action of remifentanil on heart conduction fibres. METHODS: A transesophageal pacing electrophysiological study on 40 healthy subjects scheduled for orthopaedic surgical treatment under general anaesthesia has been carried out. We determined either the correct sinus recovery time or the occurrence of Wencke-bach atrio-ventricular block in the awake state and, again, during remifentanil administration. RESULTS: In all patients either a significant depression of sino-atrial automatism or a decrease of atrio-ventricular node conduction reserve was noticed. In 2 cases, in particular, a sinus arrest and a junctional rhythm, respectively, both spontaneously recovered were observed. CONCLUSION. Atropine normalized all parameters, confirming that remifentanil-associated hypokinetic cardiac phenomena are exclusively vagally mediated.

[Peridural analgesic therapy in orthopedic surgery: comparison of ropivacaine and bupivacaine]. / Terapia antalgica peridurale in chirurgia ortopedica: confronto tra ropivacaina e bupivacaina.

The aim of our study was to compare the efficiency of ropivacaine and bupivacaine, in epidural administration, in postoperative analgesia. 20 patients, undergone knee surgery, in epidural anaesthesia (bupivacaine 0.5%-2 mg/Kg-1 administered in level L3L4), was divided into 2 groups (10 each one) and the local anaesthetics in study was administered by epidural catheter with an elastomeric pump: A (ropivacaine 0.15%) and B (bupivacaine 0.15%). The results demonstrate that ropivacaine is better than bupivacaine to keep a check on analgesia in postoperative pain.

[Use of mivacurium in orthopedic surgery: comparison of 2 different-dose inductions]. / Impiego del mivacurium in chirurgia ortopedica: confronto tra due diversi dosaggi-induzione.

The aim of our study was to evaluate the efficiency and safety of mivacurium, comparing two dose-induction in patients undergone a minor orthopaedic surgery. 30 patients were divided into two groups and mivacurium were administered at the dose of 0.15 mg Kg-1 and 0.20 mg Kg-1 respectively. The results confirmed its efficiency in short surgery. Mioresolution was excellent only in the second group (0.20 mg Kg-1) despite an histamine-related blood pressure reduction.

[Use of ropivacaine in axillary brachial plexus block]. / Impiego della ropivacaina nel blocco del plesso brachiale per via ascellare.

The aim of the study was to evaluate the efficiency and safety of ropivacaine, in comparison with bupivacaine, in axillary brachial plexus block. 24 patients, undergoing upper limb surgery, was divided into 2 homogeneous groups and the local anaesthetics was administered: A (ropivacaine 0.75%, 25 ml; total dose 187.5 mg) and B (bupivacaine 0.5%, 25 ml; total dose 125 mg). The axillary plexus block was executed with the help of an electrostimulator. The results show that using ropivacaine the onset-time is lower and the duration of sensory and motor block is higher than using bupivacaine. In conclusion we can affirm that ropivacaine is a new step in local anaesthetic field.

The use of multiple logistic function to predict surgical risk.

A method for preoperative assessment of surgical risk, in function of several risk factors, was developed using the multiple logistic function, as a model of multivariate statistical analysis. This model has the advantage to express the two considered outcomes (perioperative complications and death) in numerical terms of probability. The data were obtained from 8630 consecutive patients admitted to 62 hospitals located in various regions of Italy. The patients were divided at random into two groups: group A (6040) was used to develop the method, and group B (2590) was used as control. The method is based on the role played by seven risk factors, that were shown to be significantly related to the two outcomes. These factors are age, systolic blood pressure, pathological changes of renal function, presence of concomitant diseases, estimated duration of surgical procedure, type (major or minor) and timing of surgery, (elective, delayed or emergency). The relative and independent role of each of these factors (beta) and the value of constant alpha were estimated by maximum likelihood method. The surgical risk is assessed by solving the multiple logistic equation, and multiplying the beta values by the corresponding individual coded values of the risk factors represented by the various x's. When the method was tested by applying the computed values of alpha and beta's to assess the outcomes in the control group, the predictions resulted highly accurate (r = 0.99). To simplify the calculation of surgical risk, in appendix a computer program in Basic, already predisposed to receive in code the individual values of x's, is reported.