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Biomedical subjects

J G Murphy

Publications and source records attributed to J G Murphy.

At least 55 records · Page 3Linked to original sources
PubMed1991

Analyses of preventable deaths by mechanism of injury among 13,500 trauma admissions.

Preventable deaths (PD) were evaluated by mechanism of injury for 13,500 trauma admissions to eight hospitals over 2 years. There were 42 (3.3%) hospital deaths. Preventable deaths were analyzed by time of death, anatomic site of injury, and mechanism; penetrating (PEN) and blunt with low fall (LF) injuries were considered separately. Preventability of death for patients with probability of survival of less than 0.5, "unexpected deaths," after penetrating and blunt injuries, was determined by consensus of three trauma surgeons. Twelve per cent of deaths were found to be possibly preventable. The incidence of preventable deaths did not differ significantly across groups. Factors in preventable deaths varied by injury cause; delays in operation, PEN (50%), and blunt injury patients (48%); management errors, blunt (52%) and LF (84%); and technical errors, PEN (37.5%). Median times to death were significantly different by cause of injury: PEN, 3 hours; blunt, 13 hours; and LF, 3975 hours. Problems were identified in the hospital care of patients, especially those with LF, leading to sepsis and multiple organ failure.

Accidental Falls↗
PubMed1991

Limitations of the TRISS method for interhospital comparisons: a multihospital study.

The value of the TRISS method for interhospital comparisons of trauma care was studied using data for 5,616 consecutive patients from three trauma centers and five community hospitals. Z-scores were used to compare mortality rates. Three limitations of the method were documented: 1) the lack of homogeneity within the patient subcategory of penetrating injuries, specifically between patients with gunshot versus stab wounds; 2) the inability of the TRISS method to predict the survival rate of patients suffering low falls; and 3) the inability of the TRISS method to account for multiple severe injuries to a single body part. Remedies to the first two of these limitations can be addressed within the present TRISS method. A remedy for the third requires a new method.

Abbreviated Injury Scale↗
PubMed1990

Long-term outcome after surgical repair of isolated atrial septal defect. Follow-up at 27 to 32 years.

BACKGROUND: Atrial septal defects have been surgically correctable for more than 30 years. The long-term survival rates among patients treated in the early era of cardiac surgery are poorly documented, but such data are of critical importance to the future medical care, employability, and insurability of these patients. METHODS: To determine the natural history of surgically corrected atrial septal defects, we studied all 123 patients who underwent repair of an isolated defect (ostium secundum or sinus venosus) at the Mayo Clinic between 1956 and 1960, 27 to 32 years after the procedure. The follow-up status of all patients was determined by written questionnaires and telephone interviews. Hospital records and death certificates were obtained if interim hospitalization or death had occurred. RESULTS: The overall 30-year actuarial survival rate among survivors of the perioperative period was 74 percent, as compared with 85 percent among controls matched for age and sex. The perioperative mortality was 3.3 percent (four deaths). Actuarial 27-year survival rates among patients in the younger two quartiles according to age at operation (less than or equal to 11 years and 12 to 24 years) were no different from rates among controls--97 percent and 93 percent, respectively. In the two older quartiles (25 to 41 years and greater than 41 years), 27-year survival rates were significantly less (P less than 0.001)--84 percent and 40 percent, respectively--than in controls (91 and 59 percent). Independent predictors of long-term survival according to multivariate analysis were age at operation (P less than 0.0001) and systolic pressure in the main pulmonary artery before operation (P less than 0.0027). When repair was performed in older patients, late cardiac failure, stroke, and atrial fibrillation were significantly more frequent. CONCLUSIONS: Among patients with surgically repaired atrial septal defects, those operated on before the age of 25 have an excellent prognosis, but older patients require careful, regular supervision.

Actuarial Analysis↗
PubMed1990

Controlling for the severity of injuries in emergency medicine research.

The injury severity score (ISS) and age have been used retrospectively to control for trauma severity. Other control variables such as the revised trauma score (RTS) and the TRISS method (which estimates the probability of survival for each patient) additionally require that values of blood pressure, Glasgow coma scale, and respiratory rate, be recorded in the emergency department. The authors question when the RTS, ISS, the ISS and age, or the probability of survival calculated using the TRISS method should be used to control for severity of injuries in trauma research. Relations between predictor variables and (1) survival to hospital discharge, (2) hospital length of stay for survivors, and (3) length of ICU stay were compared by cause of injury: penetrating, motor vehicle accident, low fall, or other blunt. Data were collected over 12 months for 2,914 consecutive adult patients who died or stayed in five nontrauma and three trauma centers for 48 hours or more. For survival, the false-negative rates of probability of survival calculated using the TRISS method were approximately half that of the ISS and age; no variable adequately explained survival among those with low falls. Combinations of ISS, RTS, and age explained the most variation in lengths of hospital stay among survivors, while ISS explained the most variation in lengths of intensive care unit (ICU) stay. Researchers should consider the ISS with RTS and age to control for severity when lengths of hospital or ICU stay are studied. The TRISS method should be used in studies of survival. In both cases, the RTS which requires data collection in the emergency department must be calculated.

Adolescent↗
PubMed1990

Restenosis after balloon angioplasty. A practical proliferative model in porcine coronary arteries.

A model of proliferative human restenosis was developed in domestic pigs by using deep injury to the coronary arterial media. Metal wire coils were delivered percutaneously to the coronary arteries of 11 pigs with an oversized, high-pressure (14 atm) balloon and were left in place for times ranging from 28 to 70 days. During placement, the balloon expanded the coils and delivered them securely within the arterial lumen. Light microscopic examination of the vessels confirmed fracture of the internal elastic lamina by the coil. An extensive proliferative response occurred in 10 of the 11 pigs and was associated with a luminal area narrowing of at least 50% in all but one pig. The histopathologic features of the proliferative response were identical to those observed in human cases of restenosis after angioplasty. Immunohistochemical studies confirmed the prominence of smooth muscle cells in the proliferative tissue. A similar response was obtained in two of five porcine coronary arteries in which balloon inflation only was performed, without coil implant. This model is practical and inexpensive and closely mimics the proliferative portion of human restenosis both grossly and microscopically. Thus, it may be useful for understanding human restenosis and for testing therapies aimed at preventing restenosis after balloon angioplasty or other coronary interventional procedures.

Angioplasty, Balloon↗
PubMed1988

Mechanisms of reoxygenation-induced calcium overload in cultured chick embryo heart cells.

We examined mechanisms by which Ca enters cultured myocardial cells during posthypoxic reoxygenation. Monolayer cultures of chick embryo ventricular cells were prepared from hearts 10 days in ovo. Cells were exposed to hypoxic conditions (PO2 less than 1.5 Torr), and 45Ca uptake during subsequent reoxygenation was then examined in the absence and presence of modulators of Ca channel-dependent Ca entry and Na-Ca exchange. Modulation of Ca entry by free radical-scavenging enzymes was also examined. Hypoxia for 120 min followed by reoxygenation increased Ca content from 1.9 to 6.1 nmol/mg protein (P less than 0.05) at 30 min. Verapamil (10(-5) M) added before reoxygenation reduced Ca overload to 3.1 +/- 0.2 nmol/mg protein (P less than 0.05), but both verapamil and BAY K 8644 were without effect on modulating Ca entry if added 30 min after reoxygenation. 24Na content of cells increased from 70 nmol/mg protein in control cells to 157 nmol/mg protein (P less than 0.05) after hypoxia and reoxygenation, favoring Ca entry via Na-Ca exchange. Dichlorobenzamil significantly ameliorated reoxygenation-induced Ca overload, as did catalase and superoxide dismutase. We conclude that reoxygenation-induced Ca overload is unlikely to occur via the Ca channel. It occurs in part via Na-Ca exchange and is substantially ameliorated by enzymatic O2 free radical scavengers.

Aerobiosis↗
PubMed1987

Calcium flux measurements during hypoxia in cultured heart cells.

We tested the hypothesis that cultured chick embryo ventricular cells grown in monolayer could be used to study calcium fluxes across the myocardial sarcolemmal membrane during simulated ischemia. A specially adapted anaerobic chamber allowed the exposure of heart cells to profound hypoxia (PO2 less than 1.5 Torr) for prolonged periods of time. Ca2+ flux studies were conducted in this chamber following hypoxia and substrate deprivation to simulate important components of myocardial ischemia. To prove we were measuring cellular rather than interstitial cation contents we conducted 51Cr-EDTA interstitial space marker washout studies and showed that our procedures were sufficient to remove at least 99.7% of the extracellular fluid. The addition of lanthanum (1 mM) to the wash solution reduced nonspecific 45Ca2+ binding to the polystyrene culture plates to less than 0.03% of applied counts, but did not alter 45Ca2+ uptake under normoxic conditions. Following 2 h of hypoxia and substrate deprivation the Ca2+ content of the rapidly exchangeable Ca2+ pool of cultured monocytes increased 282% compared to control values during normoxia. We conclude that cultured chick embryo ventricular cells grown in monolayer are suitable for investigation of cation fluxes during simulated ischemia. Under the conditions studied, lanthanum displaceable Ca2+ did not make a major contribution to Ca2+ influx. The system permitted clear resolution of alterations in Ca2+ flux kinetics under conditions of profound hypoxia.

Animals↗
PubMed1987

Satisfaction with practices: emergency physicians versus internists.

No comparison has been made of satisfaction with practices of emergency physicians versus other specialists. We used a previously tested questionnaire that measures differences between current and preferred practice conditions, and with items regarding training and practice, and intention to change positions. It was sent to 250 physicians practicing emergency medicine and 250 practicing internal medicine in a metropolitan area. Both specialty types were defined by type of practice, rather than by specialty training or board certification. Ninety-five (38%) emergency physicians and 79 (32%) internists responded. Factor and correlation analyses identified six satisfaction indexes: resources, professional autonomy, administrative autonomy, patient relationships, professional relationships, and status. Physicians practicing emergency medicine were less satisfied, that is, reported more difference between current and preferred conditions, than physicians practicing internal medicine with professional autonomy, patient relations, and status (by t tests, P less than .01 for each). Emergency physicians were more satisfied with professional relationships (P less than .01). Only 40% of emergency physicians, versus 60% of internists, reported no intention to leave their present position within the next two years (P less than .02). Expectation of position change by physicians practicing emergency medicine was predicted by dissatisfaction with professional autonomy, lack of board certification, recency of graduation from medical school, and belief that monetary compensation would be higher elsewhere (R square, 0.35; P less than .01), while variables such as patient load, hours worked per week, and hospital size proved unimportant. We identified areas of dissatisfaction among emergency physicians that differed from those among internists.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

The role of calcium in ischemic myocardial injury.

Hypoxia and ischemia produce depression of myocardial contractile function and alterations in calcium homeostasis. Although both functional abnormalities and alterations in calcium handling are reversible under some conditions, reoxygenation or reperfusion can also lead to paradoxical augmentation of injury. Under many conditions of ischemia and reperfusion, however, a causal relation between altered calcium handling and cellular injury has been difficult to establish. Calcium entry through specific calcium channels during and after hypoxic insult can account for only a fraction of the observed pathologic transsarcolemmal calcium flux; sodium-calcium exchange also appears to contribute to calcium influx but to a limited degree. During reoxygenation calcium also appears to enter through nonspecific sarcolemmal permeability changes. The hypothesis that mitochondria are calcium loaded by hypoxia and reoxygenation and that the calcium loading produces mitochondrial dysfunction has not been substantiated convincingly. Brief hypoxia can produce mitochondrial dysfunction without mitochondrial calcium overload, whereas calcium overload per se does not initially produce irreversible cellular injury. Under conditions of prolonged ischemic insult, with or without reperfusion, it is likely that disturbed calcium homeostasis does play a role in ultimate cellular injury. However, available data fall short of establishing intracellular calcium overload as a necessary or sufficient condition to produce irreversible myocardial cell injury.

Animals↗
PubMed1986

Serum concentrations of meperidine in patients with sickle cell crisis.

We compared mean serum concentrations of meperidine in sickle cell patients in crisis and control patients receiving meperidine prior to incision and drainage of abscesses. Eight sickle cell and five control patients without confounding illnesses consented to participate and received 100 mg meperidine in the deltoid or gluteal muscle for pain. Blood samples were drawn at baseline, 0.25, 0.50, 0.75, 1.0, 1.5, and 2.0 hours postinjection. In the sickle cell group, mean peak concentration of meperidine was 0.32 +/- 0.08 micrograms/mL at an average of 0.5 +/- 0.07 hours postinjection. Among controls mean peak concentration was 0.72 +/- 0.37 micrograms/mL at an average of 0.6 +/- 0.11 hours. The difference in peak concentrations was significant at all time intervals (P less than .01); the difference in times to peak was not significant. We conclude that, given a standard dose, serum concentrations of meperidine differ between sickle cell and control patients, which may suggest reasons for the relatively poor pain control often noted in sickle cell patients.

Absorption↗
PubMed1985

Comparison of the performance of serum and urine hCG immunoassays in the evaluation of gynecologic patients.

We conducted a study to compare the performance of serum and urine pregnancy tests in the evaluation of gynecologic patients presenting to our ED. The overall efficiency of the two tests was very similar: 99.5% for the serum test, and 97.6% for the urine test. In patients proven to have ectopic pregnancies, however, the serum test was positive in 100%; the urine test was positive in only 60%. The serum test misclassified (gave false-negative or false-positive results) in three of 607 patients (0.5%). The urine test misclassified 14 of 607 patients (2.3%). Moreover there were 18 inconclusive or invalid urine test results. Thus the urine test provided misinformation or no information in 32 of 607, or 5.3%, of the total study population.

Chorionic Gonadotropin↗
PubMed1985

Factors that predict psychiatric consultation in the emergency department.

The purpose of the study was to determine the basis for nonpsychiatrists' decisions to obtain psychiatric consultations in an emergency department (ED) for patients with transient to moderate psychiatric symptoms. The authors reviewed ED records during July-August 1982 and January-March 1983. Complete data were gathered for 133 of 134 patients with primary or secondary psychiatric discharge diagnoses and scores on the Global Assessment Scale (GAS) such that most clinicians would not think immediate consultation was required. Information included five sociodemographic variables, psychiatric history, GAS scores, type of interaction with staff, and specificity of medical complaints. Interrater reliability of GAS coding was 81%. A total of 50% of the patients received psychiatric consultations in the ED. Both psychiatric history and GAS scores were associated with consultations (P less than 0.001 for both). Using stepwise logistic regression, psychiatric history was more important in predicting consultation (SRR = 3.0, P = 0.001) than was GAS score, which did not enter the model as a significant predictor. Social characteristics also distinguished between patients who received a psychiatric consultation in the ED and patients who did not. It was concluded that nonpsychiatrists base important management decisions on a history of psychiatric treatment for patients with transient to moderate symptoms. Whether this is appropriate needs to be studied.

Adult↗
PubMed1984

Psychiatry in the emergency department: factors associated with treatment and disposition.

Patients with psychiatric problems present difficult treatment and dispositional decisions to physicians in general hospital emergency departments (ED). We studied the relationships between the psychosocial characteristics of patients given psychiatric diagnoses and clinical decisions made by nonpsychiatrists and psychiatrists in our ED. Decisions concerning psychiatric consultation in the ED, dispositional decisions (admission, discharge), and referral for psychiatric outpatient care for patients discharged were reviewed for 246 patients. The relationships between decisions and 13 indicators of patients' psychosocial characteristics were evaluated by use of stepwise logistic regression techniques. Psychiatric-related variables (severity of symptoms, history of psychiatric hospitalization or outpatient treatment, and psychotropic medications at entry to the ED) were associated with decisions made by both psychiatrists and nonpsychiatrists. However, nonpsychiatric variables including patient's age, "rudeness," diffuseness of medical complaints, time of day, and month of presentation also were related to decisions. Practitioners should be sensitive to social factors that affect their decisions about psychiatric patients.

Adolescent↗
PubMed1984

Assessing the quality of emergency care: the medical record versus patient outcome.

The relationship between the quality of medical records and patients' health status outcomes remains unclear. For a group of patients treated and discharged with diagnoses of acute bronchial asthma, we asked: Is the quality of medical records directly and positively related to the quality of patients' health status outcomes once factors not completely within physicians' control are taken into account? Record quality was assessed by comparing information recorded with a set of criteria considered to constitute effective care. Data reflecting health status were based on telephone interviews with patients one to three and 10 to 12 days following visits. Correlation and multiple regression analyses showed the quality of records to be negatively, although not significantly, related to patients' health statuses. The results of the analyses are used to assess the adequacy of quality assurance programs concerned only with the quality of medical records, and to evaluate the advantages and disadvantages of including assessments of patients' health statuses in regular quality assurance reviews. We conclude that quality assurance programs periodically should include reviews of patients' health status outcomes.

Adolescent↗