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Biomedical subjects

W N Bernhard

Publications and source records attributed to W N Bernhard.

27 records · Page 2Linked to original sources
PubMed1978

Somatosensory evoked potentials during Harrington instrumentation for scoliosis.

The somatosensory evoked potential can be obtained in the anesthetized patient during corrective surgery on the spine. The techniques of anesthesia and somatosensory evoked potential recordings described herein were utilized in fifty-five patients during surgical correction of scoliosis with Harrington instrumentation and spine fusion. No detectable complications were encountered and no neurological morbidity ensued in our series. This method may prove to be of significant value when potential injury to the spinal cord may be encountered during correction of spinal deformities.

Evoked Potentials↗
PubMed1976

Microbial flora of the larynx, trachea, and large intestine of the rat after long-term inhalation of 100 per cent oxygen.

Effects of long-term inhalation of 100 per cent oxygen on the microbial flora of the rat larynx, trachea, and large intestine were studies. Rats were kept 14 days in an atmosphere of 100 per cent oxygen after being conditioned to high oxygen concentrations by exposure to three cycles of 100 per cent oxygen (two days) alternating with 40 percent oxygen (two days). Controls were kept under similar conditions in normal atmosphere. Rats were sacrificed, and at necropsy laryngotracheal swabs and fecal material from the large intestine were obtained and cultured for bacteria and fungi. Streptobacillus moniliformis, the predominant microorganism in the upper tracheas of controls, was not isolated from the oxygen-treated rats. Alpha-hemolytic streptococcus and Staphylococcus albus were present in control rats, but were found less frequently in rats exposed to oxygen. Pseudomonas and Proteus, infrequently isolated from controls, were predominant and sometimes the only microorganisms isolated from oxygen-treated rats. The data indicate that prolonged exposure of the rat to 100 per cent oxygen shifts the microbial flora in the upper respiratory tract from mainly gram-positive to mainly gram-negative bacteria. In contrast, there was no significant difference between the microbial flora in large intestines of control and oxygen-treated rats. The possibility that similar changes may occur in man should be considered when prolonged oxygen therapy is contemplated.

Animals↗
PubMedDate not supplied

Squamous metaplasia of tracheal epithelium associated with high-volume, low pressure airway cuffs.

The tracheas of 12 patients, intubated from 2 hours to 20 days with tracheal airways equipped with the newer style, high-volume, low-pressure (HVLP) cuffs, were examined at autopsy. The type and severity of iatrogenic damage to the epithelium and submucosa was determined and compared to that seen in a previous study of 54 patients, who had been intubated with the older-style low-volume, high-pressure (LVHP) cuffed airways. The tracheal epithelial and submucosal damage due to intubation with the HVLP cuffed airways was considerably less than that with LVHP cuffs. The submucosal glands were often spared, and some of the tracheal epithelium even survived 20 days of exposure to the "soft" cuffs. However, the pseudostratified ciliated epithelium, which normally lines the trachea, was often replaced by stratified squamous epithelium. If such a zone of nonciliated epithelium remains in the trachea of a long-term survivor, its detrimental effect on the removal of particulate matter from the tracheobronchial tree may have to be considered.

Cicatrix↗
PubMedDate not supplied

Intermittent exposure to 40 percent oxygen prolongs rat survival in 100 percent oxygen.

Prior intermittent exposure to 40 percent O2 protected rats against fatal O2 toxicity. Protection was not absolute, however, for the death of most rats in 100 percent O2 was not prevented but delayed considerably. Furthermore, those rats which did survive exposure to 100 percent O2 for long periods by virtue of prior-adaptation to increased O2 concentrations had pathologic changes in the lungs typical of chronic O2 toxicity. The very early demise of some rats indicated that 1 of 12 animals is hypersenstiive to high concentrations of inspired O2.

Adaptation, Physiological↗