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Biomedical subjects

L H Pitts

Publications and source records attributed to L H Pitts.

At least 109 records · Page 6Linked to original sources
PubMed1984

Use of the argon surgical laser in neurosurgery.

The argon surgical laser has been used in 68 neurosurgical procedures that included the removal of intracranial and intraspinal tumors, spinal cord fenestration for syringomyelia, and the production of dorsal root entry zone lesions. Characteristics that make the argon surgical laser a useful microneurosurgical instrument include the availability of a fiberoptic delivery system, a laser spot size that can be varied continuously between 0.15 and 1.5 mm, a single laser-aiming and treatment beam, the transmission of argon laser light through aqueous media such as irrigating or cerebrospinal fluids, and improved hemostasis compared to conventional techniques. The argon laser is limited primarily by its relatively low power output (less than 16 W), which makes the excision of large tumors difficult. However, even with these limitations, which can be used to advantage in the proper setting, the authors' laboratory and clinical experience suggests that the argon surgical laser may be useful in certain microneurosurgical operations.

Adolescent↗
PubMed1984

Determination of brain death.

With the careful application of the principles outlined herein, brain death can be determined with certainty. There have been no documented reports of survivors when these guidelines have been followed. The traid of a known mechanism of brain injury, absence of contributing metabolic or toxic central nervous system depression and absence of demonstrable brain function is sufficient to determine brain death clinically and, in most states, legally. The use of apneic oxygenation protects cadaver organs for transplantation during the period needed to prove that a patient cannot breathe. Very little can ameliorate the tragedy of sudden and unexpected fatal cerebral injury. Nonetheless, the concept of brain death is well established, and there is no longer a medical or an ethical reason to prolong unnecessary support of these patients.

Brain↗
PubMed1983

Pulmonary extravascular fluid accumulation following intracranial injury.

Previous investigations have reported an 11 to 71% incidence of pulmonary edema following CNS injury, based on post-mortem examinations. No premortem assessment to date has been made of the frequency and severity of in vivo pulmonary fluid accumulation following acute head injury. The thermal green dye technique was used to objectively determine extravascular lung water (EVLW) in 18 comatose patients with severe acute intracranial injuries resulting from trauma or spontaneous subarachnoid hemorrhage. Patients with aspiration, lung contusion, or pneumonia were excluded from the study. Control values for EVLW were obtained on admission from a group of 13 traumatized patients without head injury or evidence of pulmonary disease or injury. Intracranial injury patients who had EVLW values greater than two standard deviations above the control group mean were considered to have pulmonary edema. The incidence of pulmonary edema in this series was 50% (9/18). Extravascular lung water was determined post mortem in five patients using the gravimetric method of Pearce. The results suggest that pulmonary edema is a distinct clinical event occurring frequently after acute intracranial injury. Edema appears to be mediated by increased pulmonary microvascular permeability, and is not primarily dependent on postinjury changes in intracranial pressure or pulmonary vascular pressures.

Blood Pressure↗
PubMed1983

Arterial injection-digital subtraction angiography.

The authors report on a series of 60 patients who underwent arterial injection-digital subtraction angiography (AI-DSA) for evaluation of suspected cerebrospinal disease. High-quality images were consistently obtained, facilitating accurate diagnosis of a wide variety of traumatic, inflammatory, and neoplastic conditions. As experience has accumulated, the AI-DSA technique has all but supplanted conventional film-screen serialography at this institution. Important advantages of AI-DSA include reduced procedural time and decreased contrast agent burden, which mean increased patient safety. Film costs can also be markedly reduced. Moreover, image quality (information content) is not significantly affected. The technique is especially useful in emergency situations, in cases where multiple arterial injections and serialograms are required, and in cases in which transcatheter embolization is carried out. We feel these considerations will insure broadened application of this diagnostic modality as the AI-DSA equipment becomes more widely available.

Adolescent↗
PubMed1983

Correlation between angiographic vasospasm, hematoma, and ischemic brain damage following SAH.

The correlation between angiographic vasospasm, hematoma, and ischemic brain damage was studied in 29 patients who died as a result of subarachnoid hemorrhage following rupture of a saccular aneurysm. None of these patients was treated surgically. A comprehensive neuropathological examination was undertaken in each case. A significant relationship between the presence and degree of vasospasm and ischemic brain damage was found. Furthermore, even though intracerebral hematoma probably increased the risk of infarction associated with vasospasm, hematoma per se did not increase the incidence of ischemic brain damage.

Adolescent↗
PubMed1982

Head injuries.

Explore the source record for details and available documents.

Craniocerebral Trauma↗
PubMed1982

Neurological evaluation of the head injury patient.

Neurological evaluation of the head-injured patient should be rapid and as straightforward as possible. It should be performed in a manner consistent with all other evaluations of patients with similar injuries, so that complete, pertinent information can be obtained prospectively and retrospectively. The data should be recorded in a manner that ensures maximum accuracy and reliability of the initial and subsequent observations--a necessary feature if changes in the patient's status are to be recognized by the various treating personnel. The preceding sections give the essential elements of the evaluation and a brief discussion of the anatomical basis for the tests. With care and practice, all physicians can master the neurological evaluation of the patient with craniocerebral trauma so that appropriate diagnostic, therapeutic, and prognostic conclusions are reached.

Brain↗
PubMed1982

High resolution CT of thoracolumbar fractures.

Twenty-one patients with thoracolumbar spinal fractures were studied with computed tomography (CT). A vertebral body was involved in 20; 12 had additional fractures of the posterior elements. Five had multiple level injuries. Neurologic deficits occurred in nine and were more common in combined vertebral body and posterior element injury. Five patients had surgical exploration of the spinal canal. CT provided more information than plain films, which missed a vertebral body fracture in one of 20, spinal canal compromise in four of 17, and posterior element fracture in one of 12. CT showed the posterior element injuries in greater detail. CT with intrathecal contrast material showed dural tear in one case. Dural tears were found at surgery in two additional patients studied without intrathecal contrast. All three had lamina fractures and cauda equina symptoms. Prompt repair of associated nerve root herniation led to rapid recovery in two of these patients.

Adolescent↗
PubMed1981

Rapid cerebral vasodilatation in brief hypoxia in anaesthetized animals.

In anaesthetized dogs, cats and rabbits, intracranial pressure was measured continuously during brief or transient hypoxia, induced by (a) lowering inspired O2 to 9--10% for 2--3 min, or (b) giving 2--3 breaths of nitrogen. In almost all instances there was an increase in i.c.p. which started in less than 20 s; this occurred with either spontaneous or controlled ventilation, and whether or not there was also a rise in arterial blood pressure; the time course was similar to that of the arterial chemoreceptor reflex responses of ventilation and blood pressure. Division bilaterally of the sinus and vagus nerves in six cats showed that the intracranial pressure response was not dependent on these chemoreceptor afferent pathways. The results suggest a rapid vasodilatation starting at a time when cerebral arterial oxygen tension is unlikely to be below 7 kPa (50 mmHg). The mechanism remains unexplained.

Anesthesia↗
PubMed1978

Brain death, apneic diffusion oxygenation, and organ transplantation.

This paper presents a simple method of maintaining good donor organ oxygenation during a prolonged test of apnea used to determine brain death prior to cadaver transplantation. Apneic diffusion oxygenation can maintain arterial pO2 above 200 torr for periods exceeding 15 minutes, thereby allowing a more definitive determination of brain death without concomitant tissue hypoxia and possible damage to donor organs.

Adult↗
PubMed1978

Spinal cord compression and blood flow. I. The effect of raised cerebrospinal fluid pressure on spinal cord blood flow.

The effect of cerebrospinal fluid pressure (CSFP) on spinal cord blood flow (SCBF), measured by the hydrogen clearance technique, was studied in dogs. CSFP was altered by the infusion of mock CSF into the lumbar subarachnoid space. Occluding snares at T-13 limited the effect of raised pressure on the brain. As the perfusion pressure was reduced when the CSFP was increased, flow remained constant up to a perfusion pressure of approximately 50 mm Hg. Below this value, flow decreased with decreasing perfusion pressure. Normal flow values could be reestablished even at a raised CSFP if the perfusion pressure was increased by raising the arterial blood pressure. Rapid reduction of CSFP was accompanied by reactive hyperemia. The autoregulation of flow down to a perfusion pressure of 50 mm Hg was due to progressive decrease in vascular resistance. Carbon dioxide-responsiveness of the vessels was decreased markedly as the perfusion pressure was reduced.

Animals↗