Biomedical subjects

S W Corbett

Publications and source records attributed to S W Corbett.

At least 19 recordsLinked to original sources

PubMed2001

Iatrogenic cardiopulmonary arrest during pediatric sedation with meperidine, promethazine, and chlorpromazine.

The pediatric sedative combination of meperidine, promethazine, and chlorpromazine (MPC) has been widely used for more than 40 years. Despite its relatively poor efficacy and questionable safety profile, many emergency departments (EDs) continue to stock specially formulated mixtures of these three agents. We report a case of iatrogenic cardiac arrest in a 2-month-old infant in whom a consulting resident administered too much MPC (10 times the expected dose) by the wrong route (intravenous instead of intramuscular). The child was successfully resuscitated with no apparent neurologic deficit. Subsequently, we have removed MPC entirely from our ED and instituted a policy restricting ED procedural sedation privileges to emergency physicians. We urge other EDs to do likewise.

Chlorpromazine↗

PubMed2000

Benefits of an informational videotape for emergency department patients.

To determine if an informational videotape affected patient's attitudes towards their emergency department visit, we conducted a prospective study using a convenience sample of patients waiting to be seen at a southern California emergency department. Patients waiting to be treated were randomized to view an informational videotape or to receive standard management (no videotape). The informational videotape lasted 6 minutes and served to orient the patients to the emergency department. It showed the sequence of steps from entry into the department to discharge, the nature of triage and causes for delays, the different services offered by the emergency department, and the roles of each of the department staff members. One week after discharge, patients were contacted at home by telephone and were asked to rate various aspects of their emergency department experience. A comparison of the telephone survey rankings between those who viewed the videotape (98 patients) and those who did not (100 patients) revealed statistically significant improvements in the former group on questions about level of anxiety and appropriateness of delays. An informational videotape for patients in waiting areas may be a useful tool to educate about emergency medical services, to reduce anxiety, and to improve satisfaction with the emergency department stay.

Adolescent↗

PubMed2000

ED evaluation of the pediatric trauma patient by ultrasonography.

The purpose of this study was to determine the accuracy of ultrasound examination of pediatric trauma patients by emergency physicians. Pediatric (age less than 18 years) trauma patients presenting to the emergency department of a level I trauma center were prospectively examined with bedside ultrasound during the secondary survey of their trauma resuscitation. Examinations were performed by emergency medicine residents and attending physicians who had completed an 8-hour course on trauma ultrasonography. Trauma physicians providing care to the patient were blinded to the results of the examination. In 47 children (median age 9 years) computed tomography of the abdomen/pelvis or laparotomy were also performed and served as gold standards to verify the presence or absence of free fluid in the abdomen. Sensitivity, specificity, and accuracy of the ultrasound examination for the detection of free fluid in the abdominal cavity was 75% (95% confidence interval [CI] 36% to 95%), 97% (95% CI 81% to 100%), and 92% (95% Cl 77% to 98%). Positive and negative predictive values were 90% (95% CI 46% to 100%) and 92% (95% CI 74% to 99%), respectively. Ultrasound examinations took an average of 7 minutes and 36 seconds, although this did not take into consideration delays created by interruptions for other diagnostic tests or procedures. An emergency physician and radiologist agreed on blinded interpretations of 83% of the examinations (kappa = 0.56). Bedside ultrasonography is a reliable and rapid method for screening traumatized children for the presence or absence of free fluid in the peritoneum even in the hands of novice sonographers.

Adolescent↗

PubMed2000

Rattlesnake venom-induced thrombocytopenia response to Antivenin (Crotalidae) Polyvalent: a case series.

OBJECTIVE: To test the hypothesis that rattlesnake venom-induced thrombocytopenia would improve following Antivenin (Crotalidae) Polyvalent administration, and that the degree of platelet increase would correlate with the dosage of antivenom. METHODS: The authors conducted a retrospective review of all patients admitted for rattlesnake envenomation at two southern California hospitals between 1980 and 1998. Patients were included if platelet count was less than 150 x 10(9)/L following a rattlesnake bite. Patients were excluded if they received platelet transfusion. The relationship between Antivenin (Crotalidae) Polyvalent administration and venom-induced thrombocytopenia was evaluated by linear regression and paired t-test. RESULTS: The authors identified 103 cases of rattlesnake envenomation. Seventeen cases met inclusion criteria for thrombocytopenia. Two patients were excluded because they received platelet transfusions. One additional patient was excluded from paired t-test only because no antivenom was given. Thrombocytopenia usually improved between presentation and discharge (mean difference, 44 x 10(9)/L), although complete resolution was often not achieved. A statistically significant partial improvement in platelet counts immediately after antivenom administration was observed in a subset of patients with severe thrombocytopenia (platelet count <100 x 10(9)/L) (mean difference, 64 x 10(9)/L). Using regression analysis, the authors did not detect a linear relationship between the amount of Antivenin (Crotalidae) Polyvalent administered and the degree of improvement. CONCLUSIONS: Although rattlesnake venom-induced thrombocytopenia usually improves immediately after Antivenin (Crotalidae) Polyvalent administration and by the time of discharge, the degree of improvement is frequently incomplete and of uncertain clinical significance in the absence of life-threatening bleeding. The authors found no correlation between the degree of improvement and the dosage of Antivenin (Crotalidae) Polyvalent.

Animals↗

PubMed1999

Case report: reversal of an evolving myocardial infarction with intravenous thrombolysis.

This case, in many ways, represents the ideal: a timely and effective administration of thrombolytic agents. The rarity of this situation reinforces the need for earlier recognition and treatment of infarction. In an analysis of time delays in thrombolytic therapy, 38% were attributed to in-hospital issues, 22% to patients' delays, 21% to problems with transportation, and 19% to reperfusion time. The National Heart Attack Alert Program calls for treatment within 1 hour of the development of signs and symptoms, including administration of thrombolytic agents within 30 minutes of the patient's arrival in the emergency department. That program seeks heightened awareness among hospital and prehospital providers and public education about seeking immediate treatment for chest pain. The prompt acquisition of additional ECGs and the subsequent rapid administration of a thrombolytic agent were the clinical essentials. This fact suggests the need to look for measures of quality other than simple "door to drug" times. "Data to drug" times may be another indicator of quality to address cases in which the initial ECG findings are not diagnostic. Furthermore, emergency departments may see more patients with impending infarction if public education campaigns are successful. This case emphasizes the need to obtain follow-up ECGs in light of the potential benefits from thrombolysis.

Aged↗

PubMed1997

Detection of traumatic complications of cardiopulmonary resuscitation by ultrasound.

STUDY OBJECTIVE: We conducted a pilot study to assess the feasibility of ultrasonography in the detection of traumatic complications of CPR. METHODS: A prospective case series was undertaken with a convenience sample of 21 emergency department patients who sustained nontraumatic cardiopulmonary arrest. A 5- to 7-minute ultrasound examination was performed during resuscitation. The presence or absence of free fluid was noted in the left and right upper quadrants, coronal views of the kidneys, the pelvis, and the pericardium; autopsies to determine the source of fluid were not performed. Cardiac activity and the concurrent electrical rhythm were also noted. All ultrasonographers had previously been trained in the use of this technique for the evaluation of trauma patients. Examinations were stored on videotape for further review. RESULTS: Seven of 20 patients (29%) had findings on ultrasound that could have resulted from CPR-related trauma. In one additional case, findings of free fluid were probably the result of preexisting illness (ascites). Pericardial effusion was found in three patients, perihepatic fluid in four, pleural fluid in one, perirenal fluid in four, perisplenic fluid in two, and pelvic fluid in three; several patients had multiple findings. Cardiac motion with pulseless electrical activity was noted in seven patients. Five patients had return of spontaneous circulation and survived to hospitalization, and one survived to discharge. CONCLUSION: Traumatic complications of CPR are well known but typically difficult to assess. Ultrasonography may identify injuries, help guide procedures, and serve as a means to assess pharmacologic effects on cardiac performance during CPR. It is a readily available, noninvasive means to assess these critically ill patients.

Abdominal Injuries↗

PubMed1997

Stingray bites.

Explore the source record for details and available documents.

Animals↗

PubMed1996

Spectrum of injuries from snowboarding.

OBJECTIVE: To examine and compare the types, frequency, and associated risk factors of injuries sustained in snowboarders with downhill skiers. DESIGN: Prospectively administered survey. MATERIALS AND METHODS: All snowboarders and skiers who presented to a rural hospital emergency department in California during one winter season were asked to answer a survey eliciting information regarding participants' demographics, previous experience, equipment use and circumstances surrounding their injury. MEASUREMENTS AND MAIN RESULTS: An overall response rate of 87.4% yielded examination of 355 injured snowboarders. Victims tended to be male (81%) with a mean age of 19.8. Snowboarders were more likely to injure the upper limb than skiers (58% vs. 32%, respectively, p < 0.001) but less likely to injure the lower extremities (16% vs. 35%, p < 0.001). Wrist injuries were most common. Nonorthopedic injuries were less common but potentially life threatening. The data also suggest that aerial maneuvers are associated with increased risk of injury to the head, face, spine, and abdomen and that collisions are associated with more severe injury. Snow conditions had no apparent effect on the type, location, or severity of injury and the reported use of alcohol and drugs was low (7%). It was estimated that snowboarders comprised 20 to 25% of participants on the slope but represented 45% of emergency department visits. CONCLUSIONS: There exists a wide spectrum of injuries from snowboarding, ranging from common extremity injuries to potentially life-threatening nonorthopedic trauma.

Adolescent↗

PubMed1996

Asthma exacerbations during Santa Ana winds in southern California.

This study investigated the relationship between Santa Ana wind conditions and visits for asthma at a southern California emergency department. Visits to the emergency department for asthma were analyzed retrospectively to determine whether the incidence increased during Santa Ana wind conditions. These northeasterly winds are common during fall and winter in southern California and belong to a class known as Foehn winds. They are characterized by gusty winds, decreased relative humidity, warm temperatures, and decreased levels of airborne pollutants. During a 4-year period, we noted that emergency department visits for asthma increased (3.12 vs. 2.16 visits per day, P < 0.0001) during SantaAna winds compared with other weather conditions. Asthmatics presenting during Santa Ana winds appeared to be more ill, as judged by higher admission rates (21.9 vs. 18.7%, P < 0.05). These winds were also associated with reduced particulate matter (PM10) counts (P < 0.0001). Although the magnitude of the increase in emergency department visits was small, it occurred at a time when typical inciters of respiratory disease should be minimal. An as yet unidentified factor associated with these winds may be a stimulant for some asthmatics. Similar wind patterns in other localities might affect respiratory disease as well.

Air Pollutants↗

PubMed1990

Contribution of spontaneous activity to daily energy expenditure of adult obese and lean Zucker rats.

The contribution of somatomotor activity to daily energy expenditure was estimated in 10-month-old, weight-stable, obese (fa/fa) and lean (Fa/?) Zucker rats. Total and resting heat production were assessed by recording oxygen consumption and stabilimeter activity each minute for five consecutive days in free-feeding animals. The number of activity counts, as well as their circadian pattern of occurrence, were highly similar in lean and obese groups. Likewise, the percentage of daily energy expenditure committed by the obese rats to activity was nearly identical to that of leans (19.3 vs. 19.7%, respectively). Observing these rats for one additional day under postabsorptive conditions produced similar estimates of their daily expenditure on activity. Thus, unlike prior estimates based on wheel-running behavior, continuous measurement of stabilimeter behavior indicates that both the proportion of daily expenditure on activity by fa/fa rats and its temporal pattern of occurrence are notably normal. Accordingly, it is concluded that maintenance of obesity in weight-stable adult obese Zucker rats does not depend upon a reduced expenditure on activity.

Animals↗

PubMed1990

Thermogenesis following meal feeding, isoproterenol, and cold in rats with LH lesions.

Responses to several thermogenic stimuli were measured in rats maintaining stable but reduced body weights following lateral hypothalamic (LH) lesions. Oxygen consumption was monitored in open-circuit respirometers before and after exposure to cold (16.5 degrees C), intubation of a meal, and isoproterenol injection (40 micrograms/kg 0.75). Observations were made in both warm- (28 degrees C) and cold-acclimated (9 degrees C) LH-lesioned rats. Cold exposure, intubation, and drug injection each caused marked increases in heat production in sham- and LH-lesioned rats. This thermogenic response was similar in magnitude and form for both groups. Acclimation to 9 degrees C caused increased baseline levels of heat production when measured at 28 degrees C. Subsequent exposure to thermogenic stimuli revealed an exaggerated response to isoproterenol but not intubation in cold-acclimated groups. The LH-lesioned cold-acclimated rats responded in the same manner as sham-lesioned cold-acclimated rats. These findings are in contrast to the immediate postlesion period when rats show enhanced thermogenic activity. At reduced body weights LH-lesioned rats show normal rates of heat production and make normal responses to thermogenic stimuli. Enhanced thermogenesis does not appear to play a role in the maintenance of chronically reduced body mass in LH-lesioned rats.

Acclimatization↗

PubMed1990

Adjustments in daily energy expenditure to caloric restriction and weight loss by adult obese and lean Zucker rats.

The 24 h resting (postabsorptive) energy expenditure of adult female lean and obese Zucker rats was examined both at the body weights each genotype spontaneously maintained and at body weights that were reduced 6-10 percent by restricting food intake for 2 weeks to 70 or 55 percent of normal. At their normally-maintained body weight, lean rats expended energy at a daily rate appropriate to their body mass according to the Kleiber equation (predicted kcal/day = 70.0 x BW-0.75kg observed kcal/day = 70.66 x BW-0.75kg). However, expenditure rates declined significantly in the weight-reduced lean rats restricted to 70 or 55 percent of normal intake (to 64.1 and 61.3 kcal/kg0.75). The obese rats expended energy at a rate lower than predicted by the Kleiber equation prior to weight loss (49.5 x BW-0.75kg). But, rates of daily expenditure in the obese rats was further reduced by 70 or 55 percent restriction (to 43.7 and 42.4 x BW-0.75kg), a decline proportionately as large or larger than that displayed by restricted lean rats. With this reduced metabolic rate, the total daily caloric expenditure of obese rats restricted to 55 percent of normal intake approximated that of unrestricted lean rats weighing only half as much (27.8 vs 27.5 kcal/day; 569 vs 285 g). Evidently, Zucker obese rats display the same adaptive reductions in resting metabolism as do leans in response to energy deficit and weight loss. In both, these adjustments in expenditure act to stabilize body weight at the levels that typify each genotype.

Adaptation, Physiological↗

PubMed1988

Thermogenesis after lateral hypothalamic lesions: contributions of brown adipose tissue.

The role of brown adipose tissue in the thermogenic response to lateral hypothalamic (LH) lesions was investigated. Interscapular brown adipose tissue (IBAT) temperatures were measured during the hours following bilateral electrolytic LH lesions in male rats sedated with pentobarbital sodium. Local temperature changes were also recorded from skin and colonic sites. Consistent with the view that brown adipose tissue plays a primary role in the hyperthermia produced by LH lesions, IBAT depot temperature rose before, at a faster rate, and to a higher level than the other sites. In two subsequent experiments, oxygen consumption, activity, and core temperature were monitored in freely moving male rats with LH lesions, both in warm (25 degrees C) and cold (5 degrees C) environments. The results of these experiments provide some support for the view that LH lesions produce an increase in the regulated level of body temperature. This hyperthermic and hypermetabolic state seems to be mediated, in part, by brown fat thermogenesis and may represent a general increase in sympathetic nervous activity induced by the lesion.

Adipose Tissue, Brown↗

PubMed1986

Relationship of thyroid hormones and norepinephrine to the lateral hypothalamic syndrome.

The role of thyroid hormones and norepinephrine in the elevated thermogenesis seen following lateral hypothalamic (LH) lesions was investigated by measuring serum thyroid hormone levels and urinary norepinephrine excretion during the 24 hours following placement of LH lesions and again one month later when body weight had stabilized at a reduced level. During the first 24 hours following LH lesions, serum thyroxine (T4) and triiodothyronine (T3) were significantly depressed. By one month postlesion, both T4 and T3 had returned to normal. In contrast, urinary excretion of norepinephrine (NE) was increased 100% during the 24 hours following LH lesions. By one month postlesion, NE had returned to normal levels. These results indicate that the elevated thermogenesis seen shortly following LH lesions does not reflect enhanced thyroid activity, but is probably a consequence of sympathetic nervous system stimulation. The return of NE to normal levels after one month is consistent with the observation that LH-lesioned rats are by one month postlesion no longer hypermetabolic, but display levels of heat production appropriate to the reduced body weight they then maintain.

Animals↗

PubMed1986

Energy expenditure in rats with diet-induced obesity.

Effects of a diet high in fat on body weight, adiposity, and energy expenditure were investigated. Male rats were fed 8% (control) or 50% fat (by weight) for 6 mo. The high-fat group increased body weight (+26%), adipocyte size (+61%), and adipocyte number (+48%). However, food intake and resting oxygen consumption, although higher in absolute amount, were normal in that both were commensurate with the greater body mass the rats maintained. When body weight and adipocyte size were reduced by caloric restriction, the high-fat group displayed the same adaptive adjustments in resting oxygen consumption as controls. We conclude that rats fed high-fat diets for prolonged periods 1) have energy intakes and expenditures appropriate for the greater tissue mass and adipocyte number they maintain, and 2) show adaptive reductions in energy expenditure when food is restricted, which provide further evidence that the regulated level of body weight can be altered by such diets.

Adipose Tissue↗

PubMed1985

Resting oxygen consumption in over- and underfed rats with lateral hypothalamic lesions.

Rats maintaining stable, reduced body weights following lateral hypothalamic (LH) lesions were given either ad lib amounts of a palatable liquid diet or restricted amounts of a hydrated chow diet. The palatable diet produced weight gains while the diet restriction led to weight reductions in both LH- and sham-lesioned rats. Body composition analysis indicated that these changes in body mass were accounted for largely by changes in carcass fat. Resting oxygen consumption (expressed relative to body weight raised to the 3/4 power) was altered by both dietary regimens. Resting oxygen consumption in sham-lesioned rats increased by 5% following overfeeding and decreased by 13% following food restriction. LH-lesioned rats made similar responses to these dietary challenges. Overfed LH-lesioned rats increased their rate of resting oxygen consumption by 11%. Underfed LH-lesioned rats decreased oxygen consumption by 11%. These findings provide further evidence that rats with LH lesions defend a reduced level of body weight. The changes in energy expenditure that mitigate weight change in sham-lesioned animals are also present in LH-lesioned rats. In the latter, however, these adjustments serve to stabilize body weight at a lower level.

Animals↗

PubMed1984

Heat production and body weight changes following lateral hypothalamic lesions.

Factors causing rats with lateral hypothalamic (LH) aphagia to lose weight at a faster rate than food deprived controls were investigated in two experiments. In Experiment 1, the heat production of LH-lesioned and control rats was measured by indirect calorimetry for four days following surgery. A higher rate of energy expenditure was shown to account for the greater weight loss of the LH-lesioned rats. In Experiment 2, the heat production of rats receiving LH lesions either at normal or reduced body weights was measured continuously for 24 hours following surgery. Reducing body weight prior to lesioning attenuated postlesion heat production. It was also found that, though the heat production of LH-lesioned rats was consistently higher than that of nonlesioned rats of similar body weight, the fundamental relationship between body weight and heat production was unchanged by the lesion. These findings of higher rates of energy expenditure when at the same weight as nonlesioned animals, accompanied by normal adjustments in expenditure in response to weight change, are consistent with the view that LH-lesioned rats, both behaviorally and metabolically, regulate body weight at a reduced level. Their elevated rate of heat production following lesioning can be seen as an adaptive metabolic adjustment which, coupled with LH aphagia, leads to the rapid decline in body weight to a lower maintenance level.

Animals↗

PubMed1984

Characterization of the wasting syndrome in rats treated with 2,3,7,8-tetrachlorodibenzo-p-dioxin.

Treatment of male rats with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) causes a dose-dependent decrease in body weight, feed intake, resting and total oxygen consumption, and spontaneous motor activity. In animals treated with a nonlethal dose (5 or 15 micrograms/kg), feed intake and oxygen consumption recover within 3 weeks post-treatment to levels appropriate for the reduced weight of the animals. Rats treated with a lethal dose (50 micrograms/kg) lose weight continuously after treatment and typically die at a body weight approximately half that of age-matched, control rats. The similar dose and time dependencies for reduction of feed intake and weight suggest that hypophagia is the major factor responsible for weight loss in TCDD-treated rats. To determine if this hypophagia is a primary or secondary effect of TCDD treatment, rats whose body weights were reduced by food restriction prior to treatment (25 micrograms/kg) were studied. When allowed to feed ad libitum immediately after treatment, these animals exhibited relative hyperphagia and weight gain demonstrating that TCDD did not impair their capacity to feed. This finding suggests that the primary effect of TCDD is not on a system that controls feed intake, but rather on one that regulates body weight. It is proposed, as a heuristic model of the wasting syndrome, that TCDD treatment lowers a "set point" for regulated body weight in the rat in a dose-dependent fashion and that hypophagia serves, as a secondary response, to reduce the animal's weight to the lower regulation level determined by the dose administered.

Animals↗