Robert A. Hingson

Evaluation of a tapered spinal needle.

A comparison was made between a regular 25-gauge needle (RN) and a step-type needle (TN), the terminal part of the shaft of which was also 25-gauge, tapering down from 20-gauge. The study included 52 spinal procedures using TN and 90 using RN in Caucasian parturients for vaginal delivery. Only one puncture of the dura was allowed and cerebrospinal fluid had to be clear. The incidence and severity of headache was significantly higher with the TN, the 25-gauge portion of which (4.76 mm.) is only a fraction of the subarachnoid diameter in lumbar region (10 to 15 mm.). As identification of ligamentum flavum, dura, and subarachnoid space is poor, the TN tended to be advanced too far, so that its larger and thicker portion traversed the dura, causing a larger tear with subsequent cephalalgia and other sequelae. Use of the step-type of tapered needle for subarachnoid block is therefore not recommended.

Chromatographic blood-gas studies of halothane in ambulatory oral surgical anesthesia. Preliminary report of work in progress.

URING THE PAST 15 years the DepartD ment of Anesthesia of University Hospitals of Cleveland has assisted in providing general dental anesthesia for 40,000 patients in the outpatient ambulatory clinic in the Cleveland Metropolitan General Hospital for procedures ranging from simple extractions to complex multiple extractions, alveolectomies, removal of impactions, drainage of odontogenic abscesses, and simple closed reductions of maxilliary and mandibular fractures.