Biomedical subjects

R L Hewitt

Publications and source records attributed to R L Hewitt.

At least 19 recordsLinked to original sources

PubMed1977

10% Soybean oil emulsion as a myocardial energy substrate after ischemic arrest.

Explore the source record for details and available documents.

Animals↗

PubMed1976

Tracheo-innominate artery erosion: Successful surgical management of a devastating complication.

Successful management of a patient with tracheo-innominate artery erosion requires the rapid institution of specific resuscitative and operative measures. Ten patients seen at the Charity Hospital of Louisiana in New Orleans and 127 documented cases from the world literature were analyzed regarding predisposing factors, diagnostic features, resuscitative measures and operative treatment. Diagnoses associated with abnormal neck positioning were seen in 48% of patients with tracheo-innominate erosions. In 69% of 96 instances, the site of erosion was located at the cannula end and implicates excessive anterior pressure. Caution is recommended in those patients with abnormal neck positions, low placed tracheostomy stomas and individuals with asthenic habitus. Resuscitative measures were highly successful when the tracheal ballon was inflated or when the method of retrosternal finger pressure was used. All personnel providing care for patients with tracheostomies should be aware of the initial measure of ballon inflation. Operative measures which permanently interrupted the innominate artery in the area of possible future erosion were the most successful. Of the 22 cases in which the innominate artery was sacrificed, only one had evidence of cerebral ischemia. Timely institution of proper measures can result in salvage of an unexpected number of these otherwise dramatic fatalities.

Adolescent↗

PubMed1975

Cardiac contusion: a capricious syndrome.

Cardiac contusions are being recognized with frequency. Among 507 patients with non-penetrating chest injuries, 210 had serial electrocardiograms sufficient to evaluate the heart. Forty-five of these 210 patients (21%) had cardiac contusions. These 45 patients and 3 others who were confirmed to have cardiac contusions at necropsy, comprise the 48 patients in this series. Life-indangering cardiac complications occurred in 14 (29%) of the 48 patients, and 4 patients died. The development of cardiac complications following cardiac contusions appears to have a significant relationship to the presence of shock, hypoxia and to factors related to the severity of multiple injuries. These observations have therapeutic implications in management of patients with cardiac contusions through prevention of hypovolemia and hypoxia and avoidance of fluid overload as well as treatment of specific cardiac complications.

Accidents, Traffic↗

PubMed1975

Protective effect of methylprednisolone on the heart during ischemic arrest.

Although corticosteroids have been shown to stabilize lysosomal membranes and prevent release of hydrolytic enzymes, the mechanism of membrane stabilization remains obscure. The few reports regarding the use of steroids in myocardial ischemia have been conflicting. This study was undertaken to determine if a pharmacologic dose of the glucocorticoid methylprednisolone would protect the heart during ischemic cardiac arrest. A randomized double-blind study was performed in 25 dogs. Biochemical and hemodynamic parameters were assessed during and after cardiopulmonary bypass and after 30 minutes of ischemic cardiac arrest. Animals were divided into two groups. Group I served as controls and consisted of dogs injected intravenously with the vehicle of methylprednisolone 18 hours and 1 hour prior to experiment. Group II comprised dogs injected with methylprednisolone, 30 mg. per kilogram, IV, at the same time periods. Blood pH, gases, and electrolytes were measured; aortic, left atrial, and left ventricular pressures were monitored; the first derivative of the left ventricular pressure (dp/dt max.) was also determined. Arterial and coronary sinus blood samples were assayed for lactate levels and activity of the lysosomal enzyme, beta-glucuronidase. Left ventricular muscle was assayed for the nucleotides cyclic adenosine 3',5' monophosphate (AMP) and cyclic guanosine 3',5' monophosphate (GMP). Following restoration of coronary flow, mean aortic and left ventricular systolic pressures and left ventricular contractility as determined by dp/dt max. and dp/dt max./IP were depressed in both groups as expected but were significantly higher in Group II than in Group I (p less than 0.05). An increase in levels of both cyclic nucleotides occurred in each group during ischemia, but this increase in cyclic GMP was significantly greater in Group I (p less than 0.05). beta-glucuronidase activity and myocardial potassium loss as determined in coronary sinus blood were both significantly greater in Group I than in Group II (p less than 0.05). Results of this study demonstrate that pretreatment with a pharmacologic dose of methylprednisolone significantly enhances cardiac recovery after ischemia. Lysosomal membrane stability and modulation of cyclic GMP levels may be critical determinants in the mechanism of cardiac ischemia.

Animals↗

PubMed1974