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.

Malignant oedema associated with blood-sampling in sheep.

Malignant oedema is a fatal disease of several animal species, produced by one or more members of the Clostridium genus. We report here a case of malignant oedema in a 1-year-old Friesian sheep after a blood sample was collected from the jugular vein. Clostridium septicum and Clostridium sordellii were isolated from the lesions and also demonstrated by a fluorescent antibody test. This report stresses the need for maintaining a clean environment for animals and for strict hygienic measures during procedures that generate wounds, together with immunity acquired by proper vaccination, for prevention of malignant oedema.

Intracystic evaluation of tumor markers in benign and malignant ovarian pathology.

OBJECTIVE: To evaluate, in patients with benign and malignant ovarian cysts, serum samples and ovarian intracystic fluids for the presence of tumor markers such as CA 125, CA 15.3, tissue polypeptide antigen (TPA), CA 19.9 and the carcinoembryonic antigen (CEA). MATERIAL AND METHOD: We studied overall 64 patients with ovarian pathology. Sixteen patients were affected by functional cysts, 28 women by benign cystic tumors and 20 by cystoadenocarcinomas. RESULTS: Average serum levels of all but CA 15.3, TPA and CEA tumor markers of benign cystic ovarian tumors were higher than those of functional cysts. All but CA 19.9 mean intracystic fluid markers levels were more elevated in benign tumors than in functional cysts. In patients with malignant cystic tumors, all but CEA mean serum marker levels were higher than those of benign tumors; furthermore even all mean intracystic levels of markers were more elevated than those of benign tumors. CONCLUSION: This study confirmed the high positivity of tumor markers such as CA 125, CA 15.3, TPA, CA 19.9 and CEA in both the serum and intracystic fluid of patients with malignant epithelial ovarian tumors.

Transesophageal atrial pacing in the management of re-entry supraventricular tachyarrhythmias occurring during general anesthesia.

BACKGROUND: Supraventricular tachyarrhythmias (SVTs) represent an intraoperative risk factor that should be always prevented/managed. The commonly used anti-arrhythmic drugs are accompanied by intrinsic hazards, such as pro-arrhythmic and toxic effects or unpredictable onset and duration of action. We underline the therapeutic use of transesophageal atrial pacing (TAP) for the interruption of particular re-entry SVTs occurred during surgical procedures in general anaesthesia. METHODS: Our study was carried out in 25 patients characterized by a personal clinical history of transient tachyarrhythmic episodes, subjected to general anaesthesia obtained by midazolam, propofol, N2O e O2, sevoflurane, fentanil and vecuronium bromide. We used TAP bursts of 3-5 sec, their minimal pacing rate being equivalent to the tachyarrhythmia cycle length, with an impulse intensity ranging from 18 to 25 mA. In such conditions, the re-entry was interrupted by the induction of refractoriness of the wave-front that sustained the underlying arrhythmogenic circuit. RESULTS: During the study, the following arrhythmias occurred in 7 out of all patients: 1 type I atrial flutter, 3 nodal tachycardias, 1 antidromic and 2 orthodromic atrioventricular tachycardias, respectively. TAP assured either atrial capture or prompt suppression of arrhythmias in all cases. Low intensity impulses did not ever allow ventricular capture. CONCLUSIONS: TAP can be considered as a valid therapeutic device for the management of re-entry SVTs occurred during general anaesthesia, resulting it effective, safe and easy-practicable.

[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.

Effects of propofol on the human heart electrical system: a transesophageal pacing electrophysiologic study.

Previous studies have shown that infusion of propofol has sometimes been associated with bradyarrhythmias. To evaluate the effects of propofol on the electrical system of the heart, we carried out an electrophysiologic study with transesophageal pacing on ten healthy subjects scheduled for minor elective maxillo-facial surgery. By means of atrial pacing conducted by a progressive increase in stimulation cycles, we determined, in awake patients and during propofol anesthesia (2.5 mg kg-1 for induction, followed by 100 micrograms kg-1 min-1 for maintenance), the correct sinus recovery time and the eventual appearance of Wenckebach atrio-ventricular block. We did not notice sinoatrial node depression or pathologic increase in the atrio-ventricular conduction.