Comparison of digital nerve sensory recovery after repair using loupe or operating microscope magnification.

UNLABELLED: Our purpose was to determine whether there was a significant difference in sensory recovery after digital nerve repair using loupe magnification or an operating microscope. We identified patients aged 21-75 who had primary proper digital nerve repairs at least 24 months before our study. A total of 12 patients with 13 digital nerve injuries repaired with loupe magnification and nine patients with 12 digital nerve injuries repaired using the operating microscope, agreed to return for assessment by a therapist blinded to treatment. We found no significant difference in sensory recovery between the two groups as measured by static two-point discrimination, moving two-point discrimination, and Semmes-Weinstein monofilament. There were also no significant differences in average Disabilities of the Arm Shoulder and Hand or visual analogue pain scores. LEVEL OF EVIDENCE: IV.

Testosterone has potent, selective effects on the morphology of pelvic autonomic neurons which control the bladder, lower bowel and internal reproductive organs of the male rat.

Although gonadal steroids are important determinants of the development and activity of various neuronal circuits in the brain and spinal cord, their function has been relatively poorly studied in the peripheral nervous system. In the present work, the effects of pre- and postpubertal castration were examined on the morphology of autonomic neurons that supply pelvic visceral organs in male rats. These neurons were identified by peripheral injection of fluorescent retrograde tracers and, in the major pelvic ganglion, were further classified as sympathetic or parasympathetic by means of immunostaining for tyrosine hydroxylase. Sizes of ganglion cell somata were indicated by areas of nucleated profiles in cryosections. The results show that, irrespective of whether castration was carried out at two or seven weeks-of-age, noradrenergic pelvic neurons that supply the vas deferens, prostate gland, urinary bladder or colon achieved only approximately 60% of the size of those in unoperated controls. In contrast, cholinergic pelvic neurons were unaffected by castration unless they supplied reproductive targets. Pre- and paravertebral sympathetic neurons that supplied the pelvic viscera were only slightly smaller following castration or were unchanged, depending on their target. All effects of castration were prevented by testosterone replacement following surgery. Androgen receptor-immunoreactivity was particularly prevalent in the nuclei of some pelvic ganglion neurons. The studies suggest that circulating androgens are essential for the maturation and maintenance of the structure of select groups of autonomic neurons that supply the viscera. The presence of androgen receptor immunoreactivity in many of these neurons indicates that direct neuronal effects of androgens are possible. However this does not exclude other less direct mechanisms of steroid action on neurons, such as by an effect on target organs, neurotrophic factor release or peripheral vascular supply. These studies point to the androgenic steroids as potentially important determinants of autonomic reflex function.

Public Health Laboratory Service enzyme linked immunosorbent assay for detecting Toxoplasma specific IgM antibody.

An enzyme linked immunosorbent assay (ELISA) based on the antibody class capture method for the detection of specific IgM against Toxoplasma gondii, using the microtitre plate format, was developed. Antigen binding was detected using a monoclonal antibody, CIE3, conjugated to horseradish peroxidase. Prior mixing of the conjugate and antigen improved the stability of these reagents as well as removing an incubation stage from the assay. The incubation time of less than four hours permits a rapid throughput of specimens. Using the assay, a total of 163 sera were examined in a three centre study and good agreement was found. Results were expressed as arbitrary enzyme immunoassay units (EIUs) against a freeze dried standard. Throughout the study the standard serum showed a coefficient of variation less than 10% across the microtitre plate. By measuring IgM titres in patients having toxoplasmic lymphadenopathy with a known date of onset, IgM class antibodies were shown to peak at two months, persisting for about six months. In addition, a case of laboratory acquired toxoplasmosis was monitored. Sera shown to contain rheumatoid factor and antinuclear factor did not give false positive results. This rapid, robust, and simplified assay is used by the Public Health Laboratory Service Toxoplasma Reference Units and will provide a standard with which other assays can be compared.

A simple way of administering oxygen to the pediatric patient with upper airway obstruction.

An open-top oxygen tent has been developed for supplying humidified oxygen to the pediatric patient while allowing easy access to the child's head, neck, and upper thoracic region with limited impairment of either observations or movement of the child. This tent is easily and economically fabricated from 0.002-in clear plastic sheeting and 3/4-in polyvinyl chloride pipe available from a local hardware store.

Anesthesia and the geriatric patient.

The elderly patient presents a number of challenges to the anesthetist in otolaryngologic surgery, ranging from psychologic to physiologic to pharmacologic. Careful attention to the changes in physiology, with depressed or deranged function of many organ systems, requires closer monitoring of vital signs and the incremental administration of drugs. Preoperative evaluation may often be more thorough than a "minor" surgical procedure would seem to indicate, simply to ensure a good perioperative course. Balancing the necessity for perfusion of vital organs against the work load imposed on the heart involves a thorough understanding of the patient's medical condition, so that an anesthetic treatment plan may be tailored to the needs of the patient. Geriatric patients enjoy the benefits of many modern otolaryngologic procedures because of the joint efforts of the otolaryngologist and the anesthesiologist. We may expect more progress to come.

What do we do until the future gets here?

We have seen that there are serious design inadequacies in the basic anesthesia machines now in the marketplace. None of these meets criteria for technologic soundness or clinical utility elaborated in previous chapters. It is tempting to simply buy what is available and shrug one's shoulders over the situation. Those in desperate need of replacement equipment should go ahead and buy, because significant changes may be years away. However, those who are able and disposed to wait for real progress may accelerate the process by waiting not silently but loudly. Until the anesthesiologists on the firing line are consistently asking technically sophisticated questions related to safety and efficacy, expecting them to be answered, and letting their equipment budgets speak where words do not, we can expect consistent laissez-faire attitudes and actions from the anesthesia machine industry. Technology already available in other industries will continue to be overlooked or ignored, and our clinical needs will be unmet until industry is convinced that the majority of anesthetists want far-reaching substantive change in anesthesia delivery system design. We have no choice but to use what is currently available; but we can reward solid, thoughtful innovation with our capital equipment dollars, with our support of research in anesthesia technology, with our verbal and written requests to manufacturers, and with our individual time spent staying abreast of technologic issues. The ultimate beneficiaries are our patients; we cannot remain static--we must improve.

Will we see automated record keeping systems in common use in anesthesia during our lifetime? The automated anesthetic record will not automatically solve problems in record keeping.

The proponents of automated anesthetic records list the ostensibly logical reasons for them and then claim that automated records will make everything better. The logic goes as follows: (1) It is good to have accurate records because accurate records (a) make clinical decision making more effective and improve patient safety, (b) provide better defense against frivolous lawsuits, and (c) enable more astute medical policy decisions based on improved retrospective case reviews; (2) automatic record-keeping systems will give more nearly accurate records; (3) therefore, quality of care will improve if we acquire automatic record-keeping systems. This logic fails on several counts, which are detailed in this essay. Having said all this, however, I do believe that automated record systems will be implemented and they will be extremely useful, both for the patient and for those who care for the patient. However, we must exercise great care in their design and implementation, lest they wind up doing more harm than good.

The anesthesia workstation of the future.

This team's concern is that technology is not the primary limitation to developing the anesthesia workstation to its full potential. In some ways, medical equipment lags far behind other industries in technological sophistication, standardization, miniaturization, and human factors engineering. Real obstacles appear to be economic and conceptual. The anesthetic process has not been reduced to a series of rigorously derived equations; what the user does is still poorly understood. Manufacturers whose design engineers do not spend a significant part of their work week in the operating room seem to be so ignorant of the real needs of the clinician that their products are doomed to fail or to be mediocre. Clinicians need to encourage their industrial counterparts in the development process to become partners in developing the anesthesia systems of the future. Progress can only be made by having clinicians and developers spend time with one another. Can this inconvenient and frustrating process possibly be worse than the everyday torment caused by manufacturers building what the clinicians do not need, because the clinicians cannot tell them?

Components of the system: future design requirements.

A few ideas about future design concepts have been outlined and highlighted. Whether anesthetists will accept it or not, automation is the direction of the future, and data processing is increasingly important. Anesthesiology and industry need to initiate total cooperative efforts for appropriate implementation of modern technology.

System integration--the need in future anesthesia delivery systems.

Although current anesthesia delivery systems possess the virtues of familiarity, ruggedness, reliability, and longevity, problems inherent in their design require remedy. These systems consist of discrete subsystems that are unrelated physically, functionally, or by communications. Production of derived values, as opposed to raw data, is almost unheard of, although transformed data may be much more useful in the clinical environment. Future anesthesia delivery systems will use microprocessors to integrate data from multiple sensors with calculation, display, and control functions--without removing the anesthesiologist from the control loop. New ergonomic data will promote design of equipment that can be optimally manufactured, marketed, and used in clinical care. The proliferation of new equipment with advanced design and application features creates challenges for a society conscious of rising health-care costs. Creative alternatives to conventional financing, ownership, and early obsolescence of anesthesia systems must be sought in order to ensure that the quality of and capability for anesthetic care will continue to advance.

Gas and vapor delivery.

Technology for gas and vapor delivery has not changed substantively in decades. Technology possessing greater precision and reliability has been in use by nonmedical industries to regulate gas flows and to vaporize liquids. Adaptation of existing technology to the needs of anesthesia delivery systems requires stimulus from the anesthesia community and commitment from the anesthesia device industry. No insurmountable problems are evident, but the perennial problem of inertia has prevented progress consistent with that seen in other fields of biomedical technology.

ECG lead with the endotracheal tube.

We evaluated the potential of obtaining ECG signals from electrodes attached to an endotracheal tube. Tests during surgery using a 2-electrode system with 3 pediatric patients produced recordings suitable for rate monitoring and arrhythmia detection.