The nerve stimulation technique versus the loss of resistance technique for the posterior approach to lumbar plexus block: a randomized, prospective, observer-blinded, pilot study.

BACKGROUND: This prospective, randomized, observer-blinded, pilot study compares the effects of the nerve stimulation guidance technique (NS) with the loss of resistance technique (LOR) on readiness for surgery during the posterior approach to lumbar plexus block. METHODS: Thirty ASA status I-III patients who were 18-85 years old and who were undergoing hip fracture repair were enrolled. After parasacral sciatic nerve block, patients were randomly allocated to receive a continuous posterior lumbar plexus block using nerve stimulation (n=15) or a continuous psoas compartment block using the loss of resistance technique (n=15) with 20 ml of 1.5% mepivacaine. A blinded observer monitored for sensory and motor block onsets every 5 minutes. We defined readiness for surgery as complete numbness to the pinprick test and complete motor block on the surgical side. If incomplete, the lumbar plexus block was supplemented with 10 mL of 1.5% mepivacaine through the catheter before surgery. Intraoperative fentanyl or general anesthesia requirements, pain scores, local anesthetic consumption, morphine requirements for breakthrough pain and side effects were monitored. RESULTS: The mean time to readiness for surgery was 12±6 min Group NS and 22±6 min in Group LOR (P=0.03). Three patients in Group NS and 9 patients in Group LOR required additional boluses of local anesthetic through the lumbar plexus catheter before surgery (P=0.113). CONCLUSION: Nerve stimulation allowed faster readiness for surgery than loss of resistance. Nevertheless, the two techniques seem to be comparable in terms of local anesthetic consumption, morphine requirements and pain scores.

[Pressure changes in the middle ear during nitrous oxide anesthesia]. / Modificazioni della pressione dell'orecchio medio durante anestesia con protossido d'azoto.

We studied middle ear pressure variations in 17 patients with mild upper airways or middle ear diseases, during nitrous oxide anaesthesia. We observed a significant increase in middle ear pressure during the administration of nitrous oxide, and a significant decrease after nitrous oxide was discontinued. Nine patients showed periodical reductions of the middle ear pressure during the inhalation of nitrous oxide, due to passive openings of the eustachian tube. In the remaining 8 patients (47%) this mechanism has not been effective. A comparison between these two groups shows significantly higher levels of middle ear pressure in the group of patients with abnormal function of the eustachian tube, both during and after the administration of nitrous oxide. Our results demonstrate that patients with mild upper airways or middle ear diseases are likely to show an impaired tubal function. Therefore, nitrous oxide should be used with caution in the presence of such diseases. Moreover, nitrous oxide is generally controindicated in middle ear surgery, as the pressure gradients between middle and external ear can jeopardize the success of the operation.

[Comparison of a combination of fentanyl and alfentanil with propofol in brief surgery]. / Confronto tra fentanyl e alfentanil in associazione al propofol nella chirurgia di breve durata.

We studied 96 patients undergoing short gynecological procedures. Anaesthesia has been induced with fentanyl 1.5 micrograms/kg (45 patients) or alfentanil micrograms /kg (51 patients) and a hypnotic dose of propofol, and maintained with 70% N2O via facial mask. We observed a better and more rapid control of surgical analgesia with alfentanil, and an earlier recovery of postoperative psychophysical functions. Post-induction apnea has been more frequent and prolonged in the alfentanil group, but no difference in the time necessary to recover an adequate ventilation has been observed between the two groups. Alfentanil anaesthesia determined a more marked intraoperative bradycardia. By virtue of the speed of onset and the short duration of action, alfentanil is a suitable anaesthetic agent for short surgical procedures, particularly in day-stay patients.

[New methods of electrophysiologic investigation in the diagnosis of brain death]. / Nuove metodiche di indagine elettrofisiologica nella diagnosi di morte cerebrale.

In the event of suspected brain death it is vital to arrive at a diagnosis as rapidly as possible and with the least chances of error. The paper examines the potentially and possible value of BAER recordings. Results are in line with those of other published studies which underline the value of this method, in spite of the fact it is limited by the possible presence of numerous factors which might invalidate recordings.

Azlocillin and the immune response in intensive care.

The authors have followed the course of the immunological cellular and humoral parameters in 12 patients in the Intensive Care Unit at the University Polyclinic of Messina having grave infections of the respiratory apparatus, for which an antibiotic therapy with azlocillin, semisynthetic penicillin was carried out; all this with the aim of pointing out any possible interferences with the already precarious immune system in such patients. The results obtained seem to exclude any immunodepressing activity by the molecule.