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Biomedical subjects

J G Stone

Publications and source records attributed to J G Stone.

At least 19 recordsLinked to original sources
PubMed1992

Moving on: recovering from the death of a spouse.

Grieving is a complex multidimensional process in response to loss. The grief work involved in coping with a loved one's death does not end when the loved one dies. Rather, the grief work continues through a series of recovery stages. Six stages of recovery--loss, protest, searching, despair, reorganization, and reinvestment--are illustrated and discussed using a case study that highlights a wife's recovery from the death of her husband. Recognition of the stages of grief recovery after a death are significant for health care professionals so that bereavement support may be provided throughout the entire recovery process.

Adaptation, Psychological↗
PubMed1991

Dose-related effects of isoflurane associated with low plasma concentrations of verapamil on global and regional function in normal and compromised canine myocardium.

Global and regional myocardial functions were studied in seven open-chest dogs with constant low plasma concentrations of verapamil as increasing concentrations of isoflurane (0.75, 1, 1.5 MAC) were administered in the presence of normal myocardial perfusion and after application of critical constriction of the left anterior descending coronary artery. In the presence of verapamil, increases in isoflurane concentrations caused dose-dependent myocardial depression both before and after critical coronary constriction. The systemic and coronary vasodilatation associated with high concentrations of isoflurane did not occur in the presence of verapamil. The association of verapamil with isoflurane caused regional myocardial dysfunction that worsened at high isoflurane concentrations. This regional dysfunction could not be antagonized in two dogs. The effects of isoflurane on regional function were not modified by application of a critical coronary constriction.

Animals↗
PubMed1991

The grief process: a preparation for death.

Despite the multitude of losses we experience in our lifetime, death is likely to be the most paramount. Acceptance of losses and death takes time and energy as an individual passes through various phases of a process known as the grief process. Elisabeth Kübler-Ross (1969) has defined five stages in the grief process that individuals pass through in moving toward acceptance of losses. A case study has been presented to share one family's journey through these five stages. If a strict disease-oriented viewpoint is adopted, then the case was a failure: the patient died. From an emotional and spiritual viewpoint, however, this individual and his family achieved success, as they had time to complete their journey to acceptance.

Adaptation, Psychological↗
PubMed1991

Deep hypothermic circulatory arrest for the management of complex anterior and posterior circulation aneurysms.

Giant aneurysm surgery continues to be a technically difficult task with high operative morbidity. Recent advances in cardiac surgery have fueled interest in the technique of deep hypothermic circulatory arrest for the treatment of giant and complex intracranial aneurysms. Fourteen patients with giant intracranial aneurysms operated on with the technique of deep hypothermic circulatory arrest are presented. All 14 aneurysms were successfully treated. There were 2 intraoperative strokes: 1 resulted in severe disability and 1 resulted in mild disability. No significant neurological complications were related to the technique of cardiopulmonary bypass with deep hypothermic circulatory arrest. This initial experience indicates that patients with giant and complex intracranial aneurysms might benefit from a surgical approach that included the use of deep hypothermic circulatory arrest.

Adolescent↗
PubMed1990

Influence of temperature on in vitro metabolism of esmolol.

Esmolol has been used to improve hemodynamic stability during sternotomy and aortic manipulation for coronary artery bypass graft surgery. In order to investigate the alterations of esmolol metabolism by hypothermic cardiopulmonary bypass (CPB), the effect of temperature on the metabolism of esmolol in vitro was determined. Samples of human whole blood were combined with esmolol solution (50 micrograms/mL in 0.9 mol/L NaCl) and incubated at 4 degrees C, 15 degrees C, 25 degrees C, and 37 degrees C. Aliquots were sampled at 1, 5, 10, 15, 30, 60, and 120 minutes; esmolol concentration was determined using high-pressure liquid chromatography. There was a temperature-dependent decrease in the degradation of esmolol. The half-life for esmolol in human blood was 19.6 +/- 3.8 minutes at 37 degrees C, 47 +/- 10.1 minutes at 25 degrees C, 152 +/- 46.6 minutes at 15 degrees C, and 226.7 +/- 60.1 minutes at 4 degrees C. This study clearly shows marked reduction of esmolol metabolism with hypothermia possibly leading to persistent beta-adrenergic blockade following the discontinuation of CPB. Persistent beta-blockade may provide additional protection to the ischemic myocardium during hypothermic arrest and/or result in difficulty in weaning from CPB.

Adrenergic beta-Antagonists↗
PubMed1988

Risk of myocardial ischaemia during anaesthesia in treated and untreated hypertensive patients.

Hypertensive patients were monitored for myocardial ischaemia during anaesthesia and surgery with the V5 lead of a standard electrocardiograph. Myocardial ischaemia was detected in 11 of 39 untreated hypertensive patients and in four of seven receiving therapy with a diuretic, but in none of 44 receiving atenolol. Fourteen of the atenolol-treated patients were receiving the drug on a long-term basis and the remaining 30 were treated acutely only on the morning of surgery. When myocardial ischaemia was observed, it was always associated with noxious stimulation and tachycardia, but a conspicuous increase in arterial pressure was not usually present. We conclude that myocardial ischaemia is prevalent during anaesthesia in untreated hypertensive patients, and that pretreatment with atenolol, but not diuretics, provides prophylaxis.

Anesthesia↗
PubMed1988

Myocardial ischemia in untreated hypertensive patients: effect of a single small oral dose of a beta-adrenergic blocking agent.

In a non-double-blind, prospective, randomized study, the intra-operative electrocardiograms of 128 mildly hypertensive surgical patients were examined in order to determine the incidence of myocardial ischemia during anesthesia. No patient had been receiving chronic antihypertensive therapy prior to the study, but a single small oral dose of a beta-adrenergic blocking agent (labetalol, atenolol, or oxprenolol) was given to 89 of them along with premedication. Forty-four per cent of the untreated control patients and 61% of the patients pretreated with a beta-adrenergic blocking agent had normal preoperative electrocardiograms and no risk factors for coronary artery disease other than hypertension (this difference between groups was not statistically significant). During tracheal intubation and/or emergence from anesthesia, a brief, self-limited episode of myocardial ischemia was detected in 11 of 39 untreated control patients, and in two of 89 patients pretreated with a beta-adrenergic blocking agent (P less than 0.001). Tachycardia always accompanied the ischemic events, but a conspicuous increase in blood pressure did not. The authors conclude that mild hypertension, when untreated prior to the induction of anesthesia, is associated with a high incidence of myocardial ischemia; and that a single small oral dose of a beta-adrenergic blocking agent, given with pre-medication, can significantly reduce that risk.

Administration, Oral↗
PubMed1988

Global and regional myocardial blood flow and metabolism during equipotent halothane and isoflurane anesthesia in patients with coronary artery disease.

Global and regional myocardial blood flow and metabolism were examined in 20 patients with coronary artery disease before surgical stimulation. Half were anesthetized with halothane (0.8%) and half with isoflurane (1.2%). Coronary perfusion pressure decreased similarly in both groups. During halothane anesthesia coronary sinus blood flow, an index of global perfusion, decreased from an awake value of 129 +/- 7 to 97 +/- 7 ml/min (P less than 0.05), and great cardiac vein blood flow, an index of regional perfusion, decreased from 60 +/- 8 to 44 +/- 5 ml/min (P less than 0.05). In contrast, during isoflurane anesthesia global coronary blood flow increased from 131 +/- 13 to 153 +/- 16 ml/min (P less than 0.05), while regional blood flow decreased from 68 +/- 7 to 56 +/- 6 ml/min (P less than 0.05). Thus, the ratio of great cardiac vein blood flow to coronary sinus blood flow was unchanged during halothane anesthesia but decreased significantly during isoflurane. Neither global nor regional coronary vascular resistance was altered by halothane, whereas isoflurane decreased global coronary vascular resistance without affecting regional coronary vascular resistance. All patients receiving halothane had net myocardial lactate extraction. In the isoflurane group, four patients showed global lactate production and three regional lactate production. All patients demonstrating lactate production also developed electrocardiographic evidence of myocardial ischemia, which was not present before induction. The authors conclude that halothane is a preferable anesthetic to isoflurane in patients with coronary artery disease because the latter has the propensity to induce maldistribution of the coronary circulation and myocardial ischemia.

Adult↗
PubMed1987

Propranolol increases oxygen utilization during hypoxia.

The effects of propranolol on whole body oxygen consumption and blood oxygen content were measured in the dog during extreme hypoxic conditions. At 9% inspired oxygen four of eight control animals died within 40 min. An identical second group was pretreated with propranolol and none died during the same hypoxic stress. Hypoxia decreased oxygen consumption in both groups, but the decrease was less in the propranolol-pretreated dogs. A second set of 16 dogs was ventilated with 10% oxygen and all animals survived. A similar, although less pronounced, effect on oxygen consumption was noted and propranolol once again lessened the hypoxia-induced decrease in oxygen consumption. With hypoxaemia, metabolic acidosis developed in all animals and the arterio-venous oxygen content difference decreased; however, propranolol lessened the acidosis and the decrease in arterio-venous oxygen content difference. We conclude that, during hypoxia, propranolol increases oxygen utilization by the tissues and this might account for better survival.

Animals↗
PubMed1987

The association isoflurane-verapamil causes regional left-ventricular dyssynchrony in the dog.

In ten dogs anesthetized with 1% inspired isoflurane, the effect of low-dose verapamil on global and regional myocardial function was studied. The administration of verapamil resulted in no change in heart rate or blood pressure, but left ventricular stroke work, peak power, LV dP/dt max, and aortic blood acceleration were significantly reduced, while coronary blood flow remained unchanged. End-diastolic length increased in territory supplied by both left anterior descending (LAD) and left circumflex (LC) artery, but a significant decrease in systolic shortening occurred in the LAD segment only. Dyssynchrony of wall motion, characterized by post-systolic shortening, accompanied in three animals by a small amount of systolic lengthening, appeared with the administration of verapamil and was more pronounced in the LAD segment. Such patterns of wall motion have usually been attributed to myocardial ischemia. In the absence of significant reduction in coronary blood flow, and in the presence of a delay in onset of shortening and lengthening, these patterns of wall motion are more likely to reflect dyssynchrony of regional function than ischemia.

Anesthesia, Inhalation↗
PubMed1979

Hypertension during anesthesia on discontinuation of sodium nitroprusside-induced hypotension.

The authors had observed that on intraoperative discontinuation of sodium nitroprusside being administered to induce hypotension, mean arterial pressure increased to above the pre-hypotension level. Twelve patients who recieved hypotensive anesthesia for surgical correction of cerebral aneurysms were studied to evaluate the role of the renin-angiotensin system in this phenomenon. In the awake state, mean arterial pressure was 100 +/- 2 torr and plasma renin activity 3.0 +/- 0.1 ng/ml/hr. Thirty minutes after the establishment of stable halothane-nitrous oxide anesthesia, mean arterial pressure decreased to 85 +/- 1 torr and plasma renin activity increased to 4.4 +/- 0.1 ng/ml/hr. No appreciable change in either occurred over the next two hours of operation. During sodium nitroprusside-induced hypotension, mean arterial pressure decreased to 49 +/- 2 torr and plasma renin activity increased to 15.2 +/- 0.2 ng/ml/hr. Thirty minutes after discontinuation of sodium nitroprusside administration, mean arterial pressure increased to 112 +/- 2 torr, which was not only higher than the prehypotension level, but also significantly higher than that recorded in the awake state. Plasma renin activity at that time was 10.9 +/- 0.1 ng/ml/hr. As the half-life of plasma renin is 15 min, the data suggest that the persistently increased plasma renin activity is probably responsible for the increase of arterial pressure following sodium nitroprusside-induced hypotension.

Adolescent↗
PubMed1979

Comparison of intraoperative nitroprusside unloading in mitral and aortic regurgitation.

To compare the hemodynamic effect of vasodilator therapy on different regurgitant lesions, we infused sodium nitroprusside intraooperatively in 12 patients with mitral regurgitation and 15 with aortic regurgitation. During the critical period preceding establishment of cardiopulmonary bypass, both groups had developed intense vasoconstriction and cardiac decompensation. All demonstrated improved cardiac function with vasodilator therapy; however, the degree of improvement with nitroprusside differed in the two groups. Stroke volume increased 10 ml. per beat per meter squared in those patients with aortic regurgitation and only 6 ml. per beat per meter squared in those with mitral regurgitation (p less than 0.05). The percent increase in stoke volume induced by nitroprusside was inversely correlated to the preoperative left ventricular ejection fraction (r = 0.44, p less than 0.02). Patients with aortic regurgitation had lower preoperative left ventricular ejection fractions than those with mitral regurgitation (0.53 versus 0.63, p less than 0.02). Therefore, we conclude that patients with aortic regurgitation derived greater intraoperative hemodynamic benefit from unloading with nitroprusside, because they came to surgery with greater impairment of left ventricular contractility. Although nitroprusside improved cardiac function in both groups, only the patients with aortic regurgitation achieved normal pulmonary artery pressure (17 torr) and pulmonary vascular resistance (2.1 units) as a result of unloading. Those with mitral regurgitation continued to have pulmonary hypertension (28 torr) and increased pulmonary vascular resistance (3.9 units) despite vasodilator therapy. Thus the data suggest that patients with mitral regurgitation derived less hemodynamic benefit from intraoperative nitroprusside therapy because they were also limited by right ventricular dysfunction and a less responsive pulmonary vasculature.

Adult↗
PubMed1978

Hypotensive anesthesia for spinal fusion with sodium nitroprusside.

Deliberate induced hypotension for spinal fusion has been used in the past, but a search for better techniques continues. The authors used sodium nitroprusside by intravenous infusion to reduce the mean arterial pressure from 72 to 42 torr in 10 cases. This degree of hypotension provided an optimal surgical field and maintained adequate tissue perfusion as demonstrated by arterial oxygen tensions greater than 600 torr, no development of base deficit, and continuous urinary excretion. There were no complications related to hypotension. None of the patients received blood transfusions, whereas in the past, 2000 ml blood was usually required for this procedure.

Adult↗