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Biomedical subjects

Erwin F Hirsch

Publications and source records attributed to Erwin F Hirsch.

11 recordsLinked to original sources
PubMed2004

Blunt abdominal trauma: performance of CT without oral contrast material.

PURPOSE: To retrospectively evaluate multi-detector row computed tomography (CT) without oral contrast material for depiction of bowel and mesenteric injuries that require surgical repair in patients with blunt abdominal trauma. MATERIALS AND METHODS: The investigational review board approved the study. Informed consent was waived. CT reports for October 2001 to September 2003 were reviewed and 1082 patients were identified who had undergone abdominopelvic CT with a multi-detector row scanner and without oral contrast material. Findings were divided into four categories: negative, solid organ injury with or without hemoperitoneum, free fluid only, and suspected bowel or mesenteric injury. Sensitivity, specificity, positive predictive value, and negative predictive value were calculated by comparing CT findings with laparotomy reports and hospital course. RESULTS: CT findings were no intraabdominal injury (n = 932), solid organ injury only (n = 102), free fluid only (n = 34), and suspected bowel or mesenteric injury (n = 14). CT findings in patients suspected of having bowel or mesenteric injury were pneumoperitoneum with other secondary findings (n = 4), mesenteric hematoma and bowel wall abnormality (n = 2), mesenteric hematoma only (n = 4), and bowel wall thickening only (n = 4). In 11 patients, bowel or mesenteric injury was proved surgically. Thus, the study included 1066 true-negative, nine true-positive, two false-negative, and five false-positive results. Based on these data, sensitivity was 82% (95% confidence interval [CI]: 52%, 95%), specificity was 99% (95% CI: 98%, 99%), positive predictive value was 64% (95% CI: 39%, 83%), and negative predictive value was 99% (95% CI: 98%, 99%) for depiction of bowel and mesenteric injuries. CONCLUSION: Multi-detector row CT without oral contrast material is adequate for depiction of bowel and mesenteric injuries that require surgical repair. Results are comparable with previously reported data for single-detector row helical CT with oral contrast material.

Abdominal Injuries↗
PubMed2004

Trends in general surgery workforce data.

BACKGROUND: During the past 25 years, there has been much debate about general surgical workforce supply and demand. In the late 1970s and early 1980s, concern was raised by the Study on Surgical Services for the United States and the Graduate Medical Education National Advisory Council that there would be a gross oversupply of total physicians and surgeons by the years 1990 and 2000. DATA SOURCES: In a 1990 report sponsored by the Council on Graduate Medical Education, reevaluation of the workforce data showed no surplus at that time and instead predicted a deficit of surgeons by 2010. Studies by other investigators in the mid-1990s supported these conclusions. Furthermore, a new workforce model published in 2002 predicted a significant overall deficit of physicians by 2020. The discrepancies in the projected and the actual data have been explained by a variety of factors including an aging population with increased surgical needs, an increasing number of outpatient surgical procedures, subspecialization within the field of general surgery, and decreasing interest in the field by United States medical students. CONCLUSIONS: Although it is difficult to compare data among studies, and there are many confounding factors in the data, review of the workforce data does support a future deficit of surgeons, a prediction that warrants further investigation.

Career Choice↗
PubMed2004

Skeletal injury patterns in older females.

Injury patterns in elderly patients are different from those in younger patients. With recent emphasis on osteoporosis and its effects, we looked at a continuous series of patients from one Level 1 trauma center regarding injury patterns by gender. For all patients older than 65 years, and including all mechanisms, older women were more likely to sustain forearm and wrist fractures than were older men. For the individual mechanism of motor vehicle collision there was a significant increase in the extremity Abbreviated Injury Scores in older women compared with older men. Similarly, older women were more likely to sustain lower leg fractures and distal upper extremity fractures than were older men. This raises the possibility that increased bone loss, as seen in older women, may be reflected in the injury patterns they sustained given the same mechanism. More work is warranted in this region to potentially diminish these effects.

Accidental Falls↗
PubMed2003

Organ-specific changes in high-energy phosphates after hemorrhagic shock and resuscitation in the rat.

BACKGROUND: Adenosine nucleotides provide energy for many essential cellular functions. Liver and intestinal ATP and energy charge are known to decrease during hemorrhagic shock, and the ability to regenerate high-energy phosphates may have important implications for recovery. We measured organ-specific changes in energy charge after hemorrhagic shock and after shock followed by resuscitation. STUDY DESIGN: Anesthetized Sprague-Dawley rats were bled and maintained at a mean arterial pressure (MAP) of 40 mmHg for 1, 2, 3, or 4 hours. Some animals were resuscitated with normal saline and shed blood (1:1) to a mean arterial pressure of 80 to 90 mmHg for 1 hour. Control animals were anesthetized, but not hemorrhaged. At the conclusion, blood gases and adenine nucleotides were measured. RESULTS: Arterial pO2 and pCO2 were normal in all groups. Unresuscitated hemorrhage caused metabolic acidosis, but bicarbonate was normal in controls and after hemorrhage followed by resuscitation. Energy charge (EC) in the gastrocnemius was unaffected by hemorrhage or resuscitation. Liver EC decreased after hemorrhage (p = 0.0001), but recovered partially after resuscitation. Kidney EC was decreased after only 3 hours of hemorrhage and 1 hour of resuscitation (p = 0.005), but not with shorter periods of hemorrhage. Lung EC decreased with shock, but was substantially worse after resuscitation (p < 0.05). CONCLUSIONS: After hemorrhage and resuscitation, EC decreased in lung, liver, kidney, and intestine, but the time course, extent of decline, and ability to recover after resuscitation varied from organ to organ. Inability to regenerate high-energy phosphates after hemorrhagic shock may be a marker for more severe cellular damage.

Adenosine Diphosphate↗
PubMed2002

Near-infrared spectrometric determination of blood pH.

BACKGROUND: Reflectance near-infrared spectroscopy (600-2200 nm) can noninvasively probe deep into tissues. Blood is the predominant absorber of near-infrared light in biological tissues. We investigated the feasibility of using reflectance near-infrared spectroscopy to measure blood pH in vitro. METHODS: Reflectance near-infrared spectra (600-2200 nm) were obtained with a fiberoptic probe immersed in diluted human packed red blood cells maintained at 37 degrees C. Changes in pH (6.800-7.600) were induced by: (1) varying the partial pressure of carbon dioxide by the bubbling of mixtures of humidified carbon dioxide and nitrogen gas through the blood; and (2) adding 1 N HCl/NaOH. Humidified oxygen gas was bubbled through the blood to generate variations in oxygen saturation. After each titration of pH, the spectrum was recorded and blood was sampled for the measurement of: pH, pCO(2), and pO(2) using blood gas analysis; and hemoglobin concentration and oxygen saturation using co-oximetry. Samples from three separate pH titrations were combined (120 total samples) and analyzed using partial least-squares analysis to generate a mathematical model relating spectral changes to pH (calibration set). This model was then used to predict the pH of a set of 36 pH titrations (prediction set). RESULTS: Quantitative and qualitiative analyses of the spectra in the calibration set found that spectral changes in the wavelength range, 650-1050 nm, were directly related to changes in pH. First-derivative-treated spectra from the calibration set, analyzed using partial least-squares analysis, generated a mathematical model with a cross-validated r(2) of 0.939 and a standard error of calibration of 0.046 pH unit. When this model was applied to the prediction set, with an offset correction, the r(2) was 0.936 with a standard error of prediction of 0.050 pH unit. CONCLUSION: Blood pH can be predicted in vitro with clinical significance using reflectance near-infrared spectroscopy (650-1050 nm) within a standard error of 0.050 pH unit.

Calibration↗
PubMed2002

Fracture locations influence the likelihood of rectal and lower urinary tract injuries in patients sustaining pelvic fractures.

BACKGROUND: Rectal and lower urinary tract injuries in pelvic fractures can lead to significant complications. We sought to determine whether fracture locations could serve as markers for injury. METHODS: In our retrospective review of patients with blunt pelvic fractures, the association of fracture locations with injury to the rectum, bladder, and urethra was explored with Fisher's exact test and subsequently analyzed with multiple logistic regression. RESULTS: Of the 362 patients reviewed, 8 had rectal injury and 24 had lower urinary tract injury. The following locations were found to be significant. Rectum: symphysis pubis (relative risk [RR] = 3.3, p < 0.001) and sacroiliac (SI) joint (RR = 2.1, p = 0.014). Bladder: symphysis pubis (RR = 2.1, p < 0.001), SI joint (RR = 2.0, p < 0.001), and sacrum (RR = 1.6, p = 0.002). Urethra: symphysis pubis (RR = 2.9, p = 0.003), SI joint (RR = 1.8, p = 0.04), and inferior ramus (RR = 4.6, p = 0.008). After multivariate analysis, the primary and independent predictors for each of the injuries were as follows: rectal injury, widened symphysis; bladder injury, widened symphysis and SI joint; and urethral injury, widened symphysis and fracture of the inferior pubic ramus. Although these associations were significant, the overall prevalence of associated rectal and urologic injuries was low. Consequently, the predictive values of these radiologic findings were also low, ranging from 5% to 9% for urethral and rectal injuries to 20% for bladder injuries. CONCLUSION: Certain fracture locations are associated with increased risk for rectal, bladder, or urethral injury. Fractures involving these locations should prompt further work-up for assessment.

Adolescent↗
PubMedDate not supplied

Guidelines for improving nutritional delivery in the intensive care unit.

Optimizing nutritional delivery in the intensive care unit (ICU) continues to be a challenge. Nutritional guidelines were developed at a metropolitan Level I trauma center as an institutional response to ensure the timeliness of patient evaluation, initiation of therapy, and attainment of goal therapy. A post-implementation review of 525 consecutive ICU patients revealed that the guidelines enabled the staff to evaluate 86% of all ICU patients and initiate appropriate therapy in 68% of them within 48 hours of admission. Goal therapy was achieved in more than 90% of patients within 72 hours. The establishment of nutritional guidelines is an integral step to improving nutritional therapy in the ICU.

Diet Therapy↗