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Biomedical subjects

S L Roberts

Publications and source records attributed to S L Roberts.

At least 37 records · Page 2Linked to original sources
PubMed1991

Nursing management of high permeability pulmonary oedema.

In summary, the goal in managing HPPE is to recognise its occurrence and initiate appropriate treatment. While there may be a wide range of possible nursing diagnoses that have application to the HPPE patient, eight essential diagnoses were discussed and outcomes identified: impaired gas exchange; ineffective breathing pattern; ineffective airway clearance; cardiac output, alteration in; fluid volume deficit; infection, potential for; coping, ineffective individual: depression; and powerlessness.

Critical Care↗
PubMed1990

High permeability pulmonary oedema: pathophysiology and mechanisms of injury.

Many critically ill patients are at risk for developing HPPE. Since 60% of patients develop HPPE within 24 hours of the pulmonary insult with 11% developing respiratory failure within 72 hours, it is imperative that the critical care nurse understand the pathophysiological responses (Bernard & Bradley, 1986). While the pathophysiological responses are specific, injury to the alveolar-capillary membrane, the mechanisms of injury are diffuse. Knowing the mechanisms can alert health care providers to those patients who are at risk for developing HPPE and more quickly mobilize interventions to alleviate or lessen its occurrence.

Cell Membrane Permeability↗
PubMed1990

High-permeability pulmonary edema: nursing assessment, diagnosis, and interventions.

High-permeability pulmonary edema (HPPE) is a problem affecting 150,000 to 200,000 critically ill patients yearly. In HPPE the alveolar-capillary membrane is injured. The resulting increased permeability of the alveolar-capillary membrane allows shifts of fluid and protein into the interstitial fluid space and alveolus. As hypoxemia develops, the nurse assesses cardinal signs and symptoms derived from the physical examination and observations. Clinical data consisting of results from various laboratory and diagnostic studies confirm the diagnosis of HPPE. Finally, nursing diagnoses can be delineated as the basis on which expert nursing care is planned and implemented.

Blood-Air Barrier↗
PubMed1988

Comparative coronary vascular reactivity and hemodynamics during halothane and isoflurane anesthesia in swine.

To assess the dose-response effects of isoflurane and halothane anesthesia on hemodynamics and coronary artery reactivity, the authors studied myocardial hyperemic responses following brief single artery flow arrests in 21 open chest, isocapnic swine in which arterial blood pressures and cardiac outputs were recorded. A specially designed Doppler probe was used to measure the peak and time course of coronary blood flow velocity in the left anterior descending coronary artery (LAD) after 15-s LAD occlusions. The ratio of peak velocity of blood flow to resting velocity (coronary reserve), relative repayment of flow debt, and duration of hyperemic responses were studied. Surgery was performed at MAC end-tidal concentrations ([Et]isoflurane = 1.45%. [Et]halothane = 1.25%) of isoflurane (n = 7) or halothane (n = 7), and recordings were made after 15-min steady state [Et]agent at 0.5, 1, 1.25, 1.5, 1.75, 2 MAC, and further 0.5 MAC increments until the demise of each animal. To compare coronary reactivity at similar coronary pressures, an aortic snare was used to elevate arterial pressures in a third group of halothane anesthesized pigs (n = 7) to those in the previously studied isoflurane group at each MAC level. There were three major differences between halothane and isoflurane. First, cardiac depression (reduction in arterial pressure, cardiac output, and stroke volume) was less with isoflurane compared with halothane anesthesia. Second, with halothane anesthesia, there was a marked decrease in coronary reactivity independent of coronary perfusion pressures with marked, dose-dependent reductions in both coronary reserve and relative flow repayment. During isoflurane anesthesia, coronary reactivity and coronary reserve was well preserved within physiologic limits up to 1.75 MAC [Et]. Third, halothane anesthesized pigs died in cardiac collapse at much lower agent concentrations than with isoflurane (no animals survived 1.75 MAC halothane, whereas all animals survived 2.5 MAC isoflurane). Therefore, pigs anesthesized with isoflurane had greater coronary reserve, better preserved cardiac function, and greater tolerance to increasing agent concentration than pigs anesthesized with halothane.

Anesthesia, Inhalation↗
PubMed1987

Isoflurane has a greater margin of safety than halothane in swine with and without major surgery or critical coronary stenosis.

The fatal/anesthetic ratio (FAR) in 44 swine weighing 32.6 +/- 0.7 kg (SEM) was determined. Fatal anesthetic concentration (the numerator for FAR) was defined as the end-tidal concentration at which the pig lived at least 10 min, during experiments that involved step increments in anesthetic concentrations. Previously reported MAC was used as the "anesthetic" concentration (denominator) to determine FAR. Halothane was compared to isoflurane and the question of whether major surgery might reduce FAR was investigated. The major surgery groups included one open chest group with each volatile anesthetic studied during coronary reserve measurements, and two groups that had LAD critical coronary stenoses. Thus volatile agents were compared with vs without major surgery, and with vs without a critical coronary stenosis. The FAR for isoflurane was approximately double that of halothane. Further, addition of major surgery did not produce significant deterioration in FAR with isoflurane. In contrast, with halothane there was a significant (approximately 20%) decrease in FAR, despite values already only half that seen with isoflurane, when major surgery was added. Presence of a critical coronary stenosis was not associated with a worsened FAR for isoflurane or halothane. It was concluded that the fatal/anesthetic ratio for isoflurane in pigs is 1.9 times greater than that for halothane. Addition of major surgery did not affect FAR when isoflurane was the anesthetic but did when halothane was used. Critical coronary stenosis did not worsen FAR. Because these results are nearly identical with those reported previously in small mammals, the doubled safety margin seen with isoflurane may have clinical relevance.

Animals↗
PubMed1986

Pregnancy in a patient with aneurysms of the right coronary artery and an arterioventricular fistula. A case report.

A woman with aneurysms of the right coronary artery and right coronary sinus of Valsalva and a right coronary arterioventricular fistula developed angina during pregnancy. Lumbar epidural anesthesia was utilized during induction of labor and cesarean delivery. The patient had no intrapartum evidence of ischemia or congestive heart failure, and she recovered without an immediate recurrence of angina.

Adult↗
PubMed1981

Does egg feeding (i.e., dietary cholesterol) affect plasma cholesterol levels in humans? The results of a double-blind study.

In order to study the effects of dietary cholesterol in outpatients eating their usual home diets, we fed whole eggs and an egg substitute in a double-blind design to 16 normal volunteers. One-half cup of whole eggs (approximately 500 mg cholesterol) and a cholesterol-free egg substitute product were incorporated into the subjects' customary home diets for 4 wk each in a random order. Dietary cholesterol intake changed from a mean +/- SD of 196 +/- 112 mg/day during the egg substitute period to 728 +/- 119 during the whole egg period (p less than 0.001). The mean plasma cholesterol concentration during the whole egg period (243 +/- 39) was increased (p less than 0.01) 9% above the baseline level (223 +/- 40) and was increased (p less than 0.01) 11% above the egg substitute period (219 +/- 44). The mean plasma cholesterol concentration during the egg substitute period was not different from base-line. The feeding of whole egg in a double-blind study in outpatients eating their customary diets had a hypercholesterolemic effect compared to a cholesterol-free product.

Adult↗
PubMed1979

Caloric requirements for weight gain in anorexia nervosa.

The caloric requirements for weight gain were studied in 29 patients during 35 days of treatment for anorexia nervosa. Associations between the caloric requirements for weight gain and the amount of body weight depletion at the beginning of treatment were analyzed. There was a positive correlation between the percentage standard weight on the 1st day of treatment and the excess calories required to gain a kilogram. This highly significant correlation was possibly due to differences in type to tissue formed and/or an increase in metabolic rate as part of an adaptive response, as the patient nears target weight.

Adolescent↗