The effect of bipolar electrocautery on peripheral nerves.

Although bipolar cautery was designed to minimize trauma to the central nervous system, little is known about the effects of bipolar cautery on peripheral nerve tissue. This experiment was designed to study the effect of direct bipolar cautery on a peripheral nerve and the muscles innervated by that nerve. Lewis rats (n = 200) were assigned to five different groups: control, sham, and three cautery groups (duration of either 0.5, 1.0, or 1.5 seconds). The hind limb tibial nerves were isolated in the sham group and isolated and cauterized in the cautery groups. Assessments performed at 2 hours, 2 weeks, 4 weeks, and 8 weeks postoperatively included isometric contractile function studies of both a fast- and a slow-twitch muscle, muscle weights, and nerve histology/morphometry. Significant muscle weight loss and reduced muscle function were found in the cautery groups at 2, 4, and 8 weeks (p < 0.05). Histologically, the nerves of the cautery groups showed nerve damage consistent with Sunderland's type 4 nerve injury when examined at 2 weeks and showed nerve regeneration at 4 and 8 weeks. Both the fast-twitch muscle and the shorter duration cautery were associated with faster recovery relative to the slow-twitch muscles and longer duration cautery, respectively. Bipolar cautery, as administered to rat tibial nerves in this experiment, is associated with a significant injury to the nerve and loss of function of the muscles innervated by the nerve.

Bacillary angiomatosis: a new entity in acquired immunodeficiency syndrome.

Since the recognition of the acquired immunodeficiency syndrome (AIDS) in 1981, previously rare infections and neoplasms have become increasingly common. Bacillary angiomatosis, undescribed in the medical literature prior to 1983, is now second in frequency only to Kaposi's sarcoma with respect to the cutaneous manifestations associated with human immunodeficiency virus (HIV) infection. Caused by Rochalimaea henselae, bacillary angiomatosis is easily treated, when diagnosed early, with erythromycin. We present two cases of bacillary angiomatosis that presented to Toronto General Hospital and review this new and clinically interesting entity. The incidence of bacillary angiomatosis will undoubtedly increase as the HIV epidemic accelerates. Since bacillary angiomatosis commonly affects the head and neck region, it is important for the otolaryngologist to become increasingly proficient in its diagnosis and treatment. The current AIDS crisis demands that the otolaryngologist become aware not only of bacillary angiomatosis, but also of the other cutaneous head and neck manifestations of HIV infection.

Isolated sphenoid sinusitis: the Toronto Hospital for Sick Children experience and review of the literature.

Isolated sphenoid sinusitis is often misdiagnosed because of its rarity and varied clinical presentation. Presentation is often both subtle and suggestive of other intracranial etiologic sites, as determined by the anatomic relationships of the sphenoid sinus. As well, the microbiology of acute sphenoid sinusitis has not yet been clearly defined. We present three cases of acute sphenoid sinusitis and a review of the English medical literature. We isolated Staphylococcus aureus in two of our three patients at the Hospital for Sick Children and also found it to be the predominant organism in 48% of positive cultures in the literature. All three patients presented were initially misdiagnosed, as were 78% of cases in the literature.

High 2,3-DPG blood cardioplegia and myocardial preservation during cardiopulmonary bypass.

Blood may provide superior cardioplegia compared with crystalloid cardioplegic solution. However, the results are controversial. This may be due to a leftward shift of the hemoglobin (Hb)-O2 dissociation curve induced by hypothermia, increasing the oxygen affinity for Hb. This effect may negate the potential benefit of blood cardioplegia. The oxygen affinity for Hb can be decreased by increasing the red cell 2,3-diphosphoglycerate (2,3-DPG), and hence, more oxygen can be delivered to the myocardium. The present investigation was undertaken to study the effects of 2,3-DPG-enriched blood cardioplegia on the functional recovery of the myocardium and changes in the coronary sinus red blood cell (RBC) adenosine-triphosphate (ATP), lactate, and RBC DPG after one and a half hours of reperfusion following one hour of ischemic cardiac arrest in dogs. The dogs were divided into three groups: crystalloid (CR); stored blood (SB), and high 2,3-DPG blood (HDPG) cardioplegic groups. Incubation of canine RBC in phosphoenal pyruvate (PEP) led to a 36% increase in DPG and a rightward shift in the Hb-O2 dissociation curve. There was a 4 mm Hg shift in the P50. When compared with the CR group, there was a significant decrease in the cardiac index (CI) and left ventricular work index (LVWI) and a significant increase in the total systemic vascular resistance (TSVR) in the SB group. The CI and LVWI of the HDPG group were similar to those of the CR group, but the TSVR was significantly greater in the former group. The LVWI was significantly greater and the TSVR smaller in the HDPG group as compared with those in the SB group.(ABSTRACT TRUNCATED AT 250 WORDS)