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Biomedical subjects

G B Demarest

Publications and source records attributed to G B Demarest.

14 recordsLinked to original sources
PubMed1992

Protein and energy tolerance by stressed geriatric patients.

Nutritional support of stressed geriatric patients remains empiric and has classically been limited by tolerance. Although the hypermetabolic response is known to increase protein and calorie demands, tolerance to increased loads of delivered nutrients in older patients has been questioned. We compared tolerance to nutrient delivery and nitrogen metabolism in 38 stressed surgical patients over age 65 to 38 Injury Severity Score or disease matched younger controls. Twenty-seven of the 31 geriatric patients (87%) who maintained normal renal function (serum creatinine less than 2.0 mg/dl) became azotemic (BUN greater than 30) while receiving 1.5 to 2.0 g of protein per kilogram of ideal body weight compared to only 21% of controls. This phenomenon led to inaccuracies in 17% of geriatric nitrogen balance studies because of unaccounted for serum accumulation of urea nitrogen (compared to only 6% in the control group). When calculated protein requirements were administered to the geriatric group, the mean nitrogen balance was -1.6. Resting energy expenditure as measured by indirect calorimetry demonstrated a strong correlation between actual calorie expenditures and calculated needs based on the Harris-Benedict basal energy expenditure (BEE) multiplied by an activity factor of 1.2 and a stress factor of 1.75 for trauma (r = 0.86, P less than 0.05) or 1.5 for general surgery patients (r = 0.72, P less than 0.05). In summary, energy requirements by stressed geriatric patients can be closely defined by calculation of the Harris-Benedict BEE in conjunction with appropriate activity and stress factors. However, attempts to deliver traditional levels of protein lead to azotemia and are frequently unsuccessful in achieving positive nitrogen balance.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Falls and ejections from pickup trucks.

The medical records of 50 patients who sustained injuries during falls or ejections from pickup truck beds and were admitted to the University of New Mexico Level I Trauma Center between January 1985 and December 1989 were retrospectively examined. Falls and ejections commonly involve young adults, and usually occur in the summer months during the afternoon or evening. Twenty-three individuals were thrown from the pickup truck bed during a motor vehicle collision and 27 simply fell out, and this distinction was not related to age or ethanol use. Although those thrown from the pickup truck bed during a crash were less severely injured (average ISS 15.4) than those who simply fell from the bed (average ISS 17.4), this difference was not statistically significant. Mortality was equal in these two groups, with three deaths occurring in each group. Overall, injuries incurred during falls and ejections were more serious than those incurred in MVCs (average ISS 16.5 vs. 14.5, p = 0.06). The head was the most frequently injured body region following falls or ejections (68%), followed by the extremities (46%), the face (28%), the thorax (22%), and the abdomen (10%). Every death in this series was attributed to a head injury. The overall mortality for the series was 12%. Sixteen additional fatalities from falls and ejections during the study period were discovered in a review of the records of the State Medical Examiner. The average age of this cohort was 24 years. Fifteen of these deaths were the result of falls rather than ejections (94%), and 13 were attributed to head injuries (81%).(ABSTRACT TRUNCATED AT 250 WORDS)

Accidental Falls↗
PubMed1990

Barotrauma associated with high-frequency jet ventilation for hypoxic salvage.

Most reports describe reduction in proximal airway pressures with high-frequency jet ventilation. This led us to speculate that high-frequency jet ventilation might reduce barotrauma by providing alveolar ventilation at lower airway pressures. We describe a group of patients in whom a high incidence of barotrauma was observed after institution of high-frequency jet ventilation despite reduction in measured airway pressures. Fifteen hypoxic patients who could not be treated with conventional ventilation and who had no roentgenographic evidence of barotrauma were entered into the study. Airway pressures were measured during conventional ventilation and at 2 and 24 hours after high-frequency jet ventilation. Despite significant reduction in peak inspiratory and mean airway pressures, pneumothorax developed in seven of the 15 patients, an average of 21 hours after initiation of high-frequency jet ventilation. Five patients had bilateral pneumothorax and three developed tension pneumothorax. Despite reductions in proximal airway pressures, barotrauma is a significant potential complication of high-frequency jet ventilation in patients with noncompliant lungs. We currently place bilateral prophylactic thoracostomy tubes in patients with adult respiratory distress syndrome prior to initiation of high-frequency jet ventilation.

Adult↗
PubMed1990

Burn DRGs: effects of recent changes and implications for the future.

With the institution of Diagnosis Related Groups (DRGs), the economic survival of tertiary care centers may be threatened. Even more worrisome to these institutions is the possibility of other third-party payors following Medicare's lead and converting to this reimbursement plan. This paper examines the present financial status of the Burn Center at the University of New Mexico Hospital, as well as the future impact if all third-party payments were based on the DRG system. For fiscal years 1985-1987, the Burn Center lost $246,512 over cost for Medicare patients. There was a profit of $724,762 for other third-party payors, and a loss of $692,354 for indigent patients. This resulted in a total loss of $214,101 for the Burn Center during the 3-year study period. With the hypothetical conversion++ of all third-party reimbursement to DRGs, the total 3-year loss would become $1,253,393. The effect of DRG 472, a recent change in burn DRG classification, is discussed, as well as specific recommendations to rectify current problems.

Adult↗
PubMed1990

A computerized approach to injury description.

The study of trauma has been handicapped from its inception by the absence of a single coherent method of cataloging injuries. The AIS and ICD-9 systems have failed to fill this void because they lack the precision necessary to describe surgically treated injuries. We conceived a simple system of injury description in which injuries are rapidly encoded using a microcomputer in sufficient detail to distinguish among millions of different injuries. This system is easily searched by a microcomputer and allows for the automatic assignment of AIS, ISS, and CPT codes. In this system a patient is described by a 'paragraph' consisting of any number of identically patterned 'sentences,' each describing one of the patient's injuries. Each 'sentence' is composed of a string of six 'words' from controlled vocabularies and has the following structure: "Body region, Organ, Anatomic region, Injury, Physiology, Treatment." Defining the vocabulary allowed for each 'word' in a 'sentence' is complex because the allowed vocabulary is dependent upon the preceding 'words' in a 'sentence,' but in practice a microcomputer simply provides short lists of acceptable choices at each step of injury description, and records the user's selections. Additionally, the microcomputer assigns AIS, ISS, and CPT codes appropriate to the injury description sentence. The ease of data entry, the fineness of detail captured, the automation of code assignment, and the accuracy of database searching for specific injuries, classes of injuries, or combinations of injuries, we believe will give this approach widespread application in academic trauma centers where an accurate and accessible trauma database is important.

Humans↗
PubMed1990

Management of blunt hepatic duct transection by ligation.

We have reported a case of blunt trauma causing major hepatic injury and disruption of the right hepatic duct. The patient was treated with resectional debridement and ligation of the right hepatic duct; he has done well, without jaundice or signs of hepatic dysfunction. We recommend lobar hepatic duct ligation when other more conventional avenues such as primary repair or biliary-enteric anastomosis are precluded by hemodynamic instability or a nonreconstructable duct.

Adult↗
PubMed1990

Injuries in the elderly: evaluation and initial response.

The injured elderly patient presents a special challenge to the treating physician; there tends to be less margin for error than in younger patients and a greater chance that mortality will result. Beyond the general need for rapid assessment of an often complicated situation, there are specific evaluative and therapeutic techniques, system-by-system and organ-by-organ, that can help expedite the patient's recovery. Guidelines for ICU admission and possible withholding of care are also suggested.

Abdominal Injuries↗
PubMed1989

Open versus closed peritoneal lavage with particular attention to time, accuracy, and cost.

One hundred consecutive patients with blunt abdominal trauma, thoracoabdominal stab wounds, or anterior abdominal stab wounds with fascial penetration were prospectively randomized to either an open or closed technique for diagnostic peritoneal lavage. The closed or percutaneous technique of lavage was consistently faster to perform, of comparable cost, associated with fewer complications, and as accurate as the open technique.

Abdominal Injuries↗
PubMed1989

Increased pedestrian mortality among the elderly.

Elderly pedestrians struck by motor vehicles have the highest mortality rate of all pedestrian injury victims. One thousand eighty-two motor vehicle-pedestrian accidents occurring in a metropolitan area over a 5-year period were studied. Age-specific injury rates and fatality rates were evaluated with respect to the injury severity scores (ISS) for all fatally injured autopsied pedestrians. Of the 1,082 injuries, 131 fatalities occurred. Mean ISSs were found to be significantly higher for pedestrians dying at the scene of the accident (mean ISS, 54.83) and higher for those dying in the emergency department (mean ISS, 45.18), than for pedestrians who died in the hospital (mean ISS, 30.57) (P less than .0001). The mortality rate for pedestrians aged greater than or equal to 60 years was substantially higher than for those adults aged less than 60 years of age (P less than .001). Elderly patients involved in accidents were much more likely to die than younger pedestrians (44.6% v 10.4%; P less than .0001). Elderly pedestrians were significantly overrepresented in the group of pedestrians dying in the hospital compared with younger injury victims (52.5% v 21.5%; P less than .008). This study shows that elderly pedestrians struck by motor vehicles die at a higher rate because they succumb to injuries in the hospital more frequently than younger pedestrians. This may reflect the greater susceptibility of the elderly to metabolic, surgical, and infectious complications after admission to the hospital. A decrease in mortality rates of elderly patients suffering pedestrian injuries will probably follow improved in-hospital intensive care services for the elderly.

Accidents, Traffic↗
PubMed1989

Arteriography with portable DSA equipment.

Fifty-one arteriograms were obtained outside of the radiology department with portable digital subtraction angiographic equipment. Thirty-five studies were performed in the emergency room, 12 in the operating room, and four in the intensive care unit. There was a significant decrease in the time interval from arrival in the emergency room to arteriogram completion for examinations performed in the emergency room with portable equipment, compared with those performed in the radiology department. One of the 51 examinations yielded questionable results and was repeated with the conventional screen-film technique. Accurate angiographic diagnoses can be obtained by means of portable equipment in a variety of hospital locations.

Angiography↗
PubMed1989

Use of the kinetic treatment table to prevent the pulmonary complications of multiple trauma.

The kinetic treatment table (KTT) has been developed to prevent and treat complications of immobility. Because atelectasis and pneumonia may be related to immobility, we studied the effect of the KTT on the prevention and treatment of pulmonary complications in a prospective randomized study of 30 patients with severe traumatic injuries. All were receiving mechanical ventilation and were randomly assigned to treatment with a KTT or a conventional bed. Both groups received conventional medical-surgical therapy while pulmonary function, chest roentgenograms, and the presence or absence of lung infection were monitored for one week. In the patients who began the study with a clear chest roentgenogram, atelectasis and pneumonia were significantly less frequent in those treated with a KTT (P less than .05). Thus, the KTT can reduce pulmonary complications in selected patients with multiple trauma. The effect of this benefit on overall outcome is uncertain.

Adolescent↗
PubMed1979

Impaired alveolar macrophage chemotaxis in patients with acute smoke inhalation.

Pulmonary infection is a leading cause of death in patients with smoke inhalation; however, few studies have evaluated the effects of inhaled smoke on the host defense mechanisms of the lung. In this study we investigated the effects of acute smoke inhalation on the random and chemotactic (stimulated unidirectional) migration of human pulmonary alveolar macrophages. Fiberoptic subsegmental pulmonary lavage was performed in 19 normal subjects (12 nonsmokers and 7 smokers) and 7 patients with smoke inhalation. After quantification of lavaged cell populations, random and chemotactic migration was measured using modified Boyden chambers. Zymosan-activated serum was used as a chemotactic stimulant. Mean +/- SE random migration was 6.2 +/- 0.8 cells per 20 microscopic fields in smoking control subjects, 5.7 +/- 0.7 in nonsmoking control subjects, and 5.2 +/- 0.7 in patients with smoke inhalation. These values are not significantly different. In contrast, the mean directed (chemotactic) migration of pulmonary alveolar macrophages was 26.5 +/- 1.9 in smoking control subjects, 22.7 +/- 3.0 in nonsmoking control subjects, and 11.4 +/- 1.4 in patients with smoke inhalation; the latter response was significantly different from that of the smoking (P less than 0.001) and nonsmoking (P less than 0.025) control subjects and the combined average of the 2 control groups (P less than 0.001. In vitro exposure of pulmonary alveolar macrophages to nontoxic doses of smoke produced similar impairment of chemotaxis. These findings may partially explain the enhanced susceptibility of patients with smoke inhalation to pulmonary infection.

Adult↗
PubMedDate not supplied

Obligatory negative nitrogen balance following spinal cord injury.

Obligatory nitrogen losses due to paralysis in the spinal cord-injured (SCI) patient prevent positive nitrogen balance (NB) regardless of the calorie and protein intakes. Ten patients with SCI and 20 controls with nonspinal cord injury (NSCI) matched for time, sex, age, and injury severity score (ISS) were admitted to our Level I trauma center. In both groups, total nutritional support was delivered within 72 hours of admission based on predicted energy expenditures (PEE = Harris-Benedict equation x 1.2 x 1.6) and 2 g of protein/kg of ideal body weight (IBW). Subsequent changes in nutrient delivery were based on NB. No SCI patient established positive NB during the 7-week period following injury despite an average delivery of 2.4 g of protein/kg IBW and 120% of the PEE at the time of peak negative NB (-10.5). In six SCI patients, an average increase of 25% in delivered protein and 12% in delivered calories over a 1-week period effected no change in average NB (-7.4 vs -6.8). Indirect calorimetry in five SCI patients showed that calorie intakes were 110% more than average measured energy expenditures. In contrast, 17 of 20 NCSI patients achieved positive NB within 3 weeks of admission. They required an average delivery of 2.3 g of protein/kg IBW and 110% of PEE to reach positive NB. These data demonstrate the phenomenon of obligatory negative NB acutely following SCI. Aggressive attempts to achieve positive NB in these patients will fail and result in overfeeding.

Adult↗