THE RESUSCITATION OF THE CENTRAL NERVOUS SYSTEM OF MAMMALS

Gasping in Dying Children: Health Care Professionals' Feelings and Knowledge

Purpose: To assess the feelings and knowledge of health care professionals (HCPs) about gasping in dying patients in neonatal intensive care units (NICUs) and pediatric intensive care units (PICUs). Methods: A 9-item questionnaire addressed to 488 HCPs (physicians, nurses, and nursing assistants) of 2 NICUs and 2 PICUs. Questions were about HCPs' feelings when confronted with gasping, their knowledge, and their opinions on what to tell family members. Results: Responses were obtained from 248 staff members. Of the respondents, 43% felt that gasping was painful to the patient and most felt that witnessing gasps was distressing for the parents, and 77% reported being distressed by witnessing gasps. Conclusions: Efforts are needed to educate HCPs about the physiology of gasping, to help them to cope with gasping, and to give better support to parents.

The Death Watch: Certifying Death Using Cardiac Criteria

In the past, inadequate diagnostic instruments sometimes led to incorrect diagnoses of death, so careful and prolonged observation—the “death watch”—was required. Diagnostic instruments are now accurate and determining the presence or absence of circulation and cerebral function is easy in virtually all cases. Still, ambiguity and controversy in diagnosing death persists because the current criteria, irreversible cessation of cardiac or whole brain function, are ambiguous. Recent reintroduction of Non—Heart-beating organ donation has highlighted the controversy. Data on the ability to achieve restoration of spontaneous circulation are quite consistent, but they support several different sets of reasonable death criteria. This article concludes with a rejection of a fixed notion of “irreversibility” because it does not conform to current practice, is potentially deleterious to social events at the time of death, and the reversibility of cardiopulmonary arrest is dependent on available means of resuscitation. Finally, the time required to ensure irreversible cessation of cardiac function despite potential intervention is too broad to be clinically applicable and is unreasonable. Diagnosis of death should be based on the context in which it occurs because the medical means available determine what is irreversible.

Aneurysmal subarachnoid hemorrhage models: do they need a fix?

The discovery of tissue plasminogen activator to treat acute stroke is a success story of research on preventing brain injury following transient cerebral ischemia (TGI). That this discovery depended upon development of embolic animal model reiterates that proper stroke modeling is the key to develop new treatments. In contrast to TGI, despite extensive research, prevention or treatment of brain injury following aneurysmal subarachnoid hemorrhage (aSAH) has not been achieved. A lack of adequate aSAH disease model may have contributed to this failure. TGI is an important component of aSAH and shares mechanism of injury with it. We hypothesized that modifying aSAH model using experience acquired from TGI modeling may facilitate development of treatment for aSAH and its complications. This review focuses on similarities and dissimilarities between TGI and aSAH, discusses the existing TGI and aSAH animal models, and presents a modified aSAH model which effectively mimics the disease and has a potential of becoming a better resource for studying the brain injury mechanisms and developing a treatment.

THE HISTOLOGICAL CHANGES IN NERVE CELLS DUE TO TOTAL TEMPORARY ANAEMIA OF THE CENTRAL NERVOUS SYSTEM

With the return of the circulation, dilation of the pericellular lymph space and slight swelling of the cell body occurs, disappearing as recovery progresses. Chromatolysis, as evidenced by poor affinity for stains, clumping, diffuse staining, and breaking into dust-like particles, induced by anaemia, is not necessarily fatal. Death of the cell is not shown histologically when tissue is removed and fixed immediately after the experiment. Some time must elapse for the detection of the vacuolation, displacement of the nucleus and solution of the chromatic substance, indicative of profound changes. Neurones from different regions as well as neurones of the same region differ in degree of resistance to anaemia. The small pyramidal cells are the most susceptible, and then come the Purkinje cells, cells of the medulla oblongata, retina, cervical cord, lumbar cord, spinal ganglia and, most resistant of all, the sympathetic ganglion cells. Failure to resuscitate animals after anaemia of the central nervous system is probably due to the destruction of many of the cells of the vital centers (vaso-motor and respiratory) which do not have histological peculiarities by which they may be defined. Death, however, of a few cells of any center does not necessarily mean the total loss of function of that center, since the remaining cells may be sufficient to discharge the function of the center.

The death watch: certifying death using cardiac criteria

In the past, inadequate diagnostic instruments sometimes led to incorrect diagnoses of death, so careful and prolonged observation--the "death watch"--was required. Diagnostic instruments are now accurate and determining the presence or absence of circulation and cerebral function is easy in virtually all cases. Still, ambiguity and controversy in diagnosing death persists because the current criteria, irreversible cessation of cardiac or whole brain function, are ambiguous. Recent reintroduction of non-heart-beating organ donation has highlighted the controversy. Data on the ability to achieve restoration of spontaneous circulation are quite consistent, but they support several different sets of reasonable death criteria. This article concludes with a rejection of a fixed notion of "irreversibility" because it does not conform to current practice, is potentially deleterious to social events at the time of death, and the reversibility of cardiopulmonary arrest is dependent on available means of resuscitation. Finally, the time required to ensure irreversible cessation of cardiac function despite potential intervention is too broad to be clinically applicable and is unreasonable. Diagnosis of death should be based on the context in which it occurs because the medical means available determine what is irreversible.

Experimental cervical myelopathy. Effects of ischemia and compression of the canine cervical spinal cord

The authors report experiments designed to test the effect of regional ischemia induced by selective vascular ligations and anterior compression of the cervical cord at two adjacent segments (C-4, C-5) in the same dog. They conclude that local ischemia of the cervical cord, caused by local deformation, when superimposed on a regional reduction in spinal cord blood flow, accounts for the myelopathy of cervical spondylosis whether produced experimentally in animals or occurring naturally in man.

Acute canine cerebral ischemia: a preliminary model to evaluate microvascular mammary-carotid anastomosis

Although the dog remains the standard surgical laboratory animal, its extensive collateral circulation makes complete interruption of cerebral blood flow quite difficult. A simple yet reliable canine model for the study of cerebrovascular insufficiency would seem desirable. We have found that complete division of the left subclavian and right brachiocephalic arteries and their major branches can be rapidly performed through a small left thoracotomy. This interruption of blood supply is incompatible with resumption of normal respiratory function, consciousness, or survival, and can be used to evaluate extra-anatomic grafts or anastomoses.