James R. Mackenzie

Complications of Femoral Neck Fracture in Young Adults

Femoral neck fractures are uncommon but serious injuries in young adults, with high rates of nonunion and avascular necrosis reported. This study was undertaken to examine the relationship between the mechanism and severity of injury, anatomic site of fracture, health status, and method of therapy on the incidence of these complications in young adults. The hospital records of 32 skeletally mature patients between the ages of 15 and 50 years (mean, 33) treated for femoral neck fracture between 1975 and 1982 were reviewed, and data analyzed for the 25 patients with a minimum 2-year followup (mean, 61 months). Data pertaining to the cause of injury, fracture pattern, prior health status, overall injury severity, method of fracture treatment, and long-term outcome were analyzed. Nonunion of the fracture site was observed in five (20%); avascular necrosis in nine (36%). Of patients with subcapital fracture 83% developed nonunion or avascular necrosis, compared to 21% with true femoral neck fracture (p = 0.05). There was no difference in cause of injury, overall injury severity, degree of comminution, displacement, method of treatment, or prior health status between those with and without complications. In this study, high rates of nonunion and avascular necrosis were seen after all types of femoral neck fracture in young adults, but were more often associated with subcapital fracture. These complications of hip fracture appeared to be independent of health status, method of treatment, or mechanism or severity of injury.

Diagnosis of isolated small bowel injury following blunt abdominal trauma

A review of the case histories of 29 patients with isolated rupture of the small bowel was undertaken to determine which diagnostic tests were most sensitive in the early diagnosis of this notoriously occult injury. Results indicate that peritoneal lavage was the most useful test for this purpose, clearly more sensitive than standard clinical or radiographic signs. All patients in this series had indications for peritoneal lavage, and 85% of the patients who underwent peritoneal lavage in the emergency department had positive results and prompt operation. Reliance on the development of clinical peritonitis or the detection of pneumoperitoneum leads to long delays before operation.

Is the flight physician needed for helicopter emergency medical services

The question of whether physicians are cost effective in helicopter emergency medical services (HEMS) transport remains an unresolved issue. During a four-month study period, all physician-specific contributions to medical care were recorded by means of a questionnaire that was completed by the flight physician and the flight nurse after each flight. In the judgment of the nurse, the flight physician made a unique and important contribution to the care of the patient in 38 of 174 flights (22%) completed during the study. Judgment, the most common contribution, was cited on 29 flights (17%). Both skill and judgment were contributed on seven additional flights (4%), and skill alone on only two flights (1%). Judgment was exercised most frequently in making diagnoses, initiating critical medical treatments, and determining destination. The cost to this program of providing physicians is approximately

Indications for aortography in blunt thoracic trauma: a reassessment.

85,000 per year, or 7% of an annual budget of approximately

Enhanced capillary blood flow in rapidly expanded random pattern flaps.

1.2 million. Flight physicians make a substantial and important contribution to patient care in HEMS operations, exercising critical judgment regarding diagnosis, medical treatment, and disposition in 22% of transports. The benefits of this contribution far outweigh the 7% program cost.

Therapeutic intervention scoring as a measure of performance in a helicopter emergency medical services program

The indications for aortography in patients sustaining blunt chest trauma have increased as the number of radiographic and clinical findings associated with traumatic rupture of the thoracic aorta (TRA) proliferate. No studies, however, have demonstrated whether these findings are useful in selecting patients for aortography. In order to determine the predictive value of reported associations in TRA, the presence or absence of nine radiographic and nine clinical findings associated with TRA were tabulated and tested for correlation with the results of aortography in 173 consecutive patients who underwent arch aortography from 1975 to 1980 to rule out TRA following blunt trauma. Mediastinal widening was the most reliable indicator of TRA. All patients less than 65 years old with TRA presented with mediastinal widening. In patients under 65, the reliability of mediastinal widening to predict TRA was not enhanced by any other clinical or radiographic finding studied. On the other hand, only two of six TRAs in patients over 65 had mediastinal widening. Only in this group over 65 did other publicized indications for aortography, including pulmonary contusions or multiple rib fractures including ribs 1 and 2, have any association singly or in combination with TRA. We conclude that all trauma victims who have a widened mediastinum should undergo aortography. Other reported associations by themselves are not absolute indications for aortography except in patients 65 years old or older.

Thoraco-abdominal response and injury

We have quantitatively examined the effect of rapid sequential skin expansion on capillary blood flow in the porcine random flap model in order to determine the relation between the increased survivability of expanded random flaps and capillary blood flow. Three 6 X 20 cm random flaps were tattooed on the backs of six small (20-kg) pigs. One flap was not manipulated (control). A 450-ml expander was inserted at the base of the second flap and left in place (sham). At the base of the third flap a 450-ml expander was inserted and each day for 5 days sequentially filled to the limits of skin viability as determined by vital dye staining (expanded). Capillary blood flow was measured on day 8 by measurement of radioactivity after injection of 15-microns radiolabeled microspheres. Samples were taken at 4-cm intervals from the base of each flap. Rapid expansion led to significant increases in capillary blood flow in expanded skin and to enhanced preservation of capillary flow after elevation of random pattern flaps based on expanded skin compared to sham and to control tissues. This correlates with and explains at least in part our previous observation of improved length of survival of flaps raised on expanded skin.

Clinical scoring does not accurately assess hypoxemia in pediatric asthma patients

Helicopter emergency medical services (HEMS), which are both expensive and resource intensive, lack objective measures for system evaluation. We computed the Therapeutic Intervention Scoring System (TISS) score for all patients during six consecutive months of service in a HEMS program to assess the value of this score for measuring the performance of the program. The TISS assigns values ranging from 1 to 4 for 57 medical and surgical interventions to measure the intensity of care during a 24-hour period. The TISS was recorded for 203 patients beginning at the time HEMS transport was requested. These flights also were classified as appropriate or inappropriate, given the information available, when HEMS care was initiated and days later when diagnostic evaluation was complete. Classification was done on the basis of whether the following criteria (potentially) ensure patient survival or improve outcome: speed of transport, presence of a medically skilled flight team, or the helicopters ability to overcome hostile environmental conditions. The mean TISS score for all patients was 21.7. One hundred thirty-two of 203 flights (65%) were thought to be medically necessary, both at the time HEMS was requested and later (mean TISS, 28.1; analysis of variance, P less than .001). Thirty-four flights (17%) were thought to be appropriate using the information available at flight time, but not after the diagnostic workup was completed (mean TISS, 10.0). Thirty-six patients (18%) did not appear to require helicopter transport at any time, and had a mean TISS of 9.0. We conclude that TISS is a useful, objective measure of the performance of a HEMS program, and it should be tested in other HEMS programs.

Predicting the utilization of helicopter emergency medical services: An approach based on need

The response of human cadavers and live anesthetized and postmortem primates and canines to blunt lateral thoraco-abdominal impact was investigated using a 10 kgm. free-flying mass. Injuries were evaluated by gross autopsy, and for live subjects, also by sequential peritoneal lavage and biochemical assays. Mechanical measurements included force time history, intra-aortic pressure, and high-speed cineradiography. The X-ray cineradiograph was shown to be invaluable as an in vivo, noninvasive technique for quantifying the motion of internal structures during impact. The hearts response during the time of contact was affected by interactions with other material bodies (diaphragm, thoraco-abdominal wall, and lung tissue). During impacts of 12 msec. or less, the hepatic system acted as a deformable structure. Injury severity (Abbreviated Injury Scale) was lower for the unpressurized postmortem subjects than for the live subjects. Elevated levels of the enzymes glutamic-oxalacetic transaminase and glutamic-pyruvic transaminase occurred in both the circulatory system and the peritoneal cavity within one half hour following blunt abdominal impact trauma. Evaluation of abdominal injury severity by gross autopsy was found to lack interpretation of such critical factors as hemorrhaging.

Sequential peritoneal lavage and early diagnosis of colon perforation

Management of acute asthma in the pediatric population is based almost entirely on clinical evidence of severity. Although pulmonary function testing has been advocated to improve evaluation, it is difficult in the pediatric patient and not routinely practiced. A clinical scoring system has been devised to help standardize evaluation, but has not been validated by comparison of the results of clinical scoring with those of arterial blood oxygen levels as determined by blood gas analysis. This study was undertaken to compare clinical scoring of pediatric asthma patients with the results of arterial blood gas analysis. Thirty-eight children between the ages of 2 and 13 having 42 episodes of acute asthma were evaluated. The average age was 5.4 years. The average clinical score was 2.62; arterial blood for analysis was obtained in 37 (88%), with an average PaO2 of 81.7 mm Hg. None of the children had CO2 retention. There was no correlation between the clinical score of the children on presentation and the severity of hypoxia (correlation coefficient = -0.149). Comparison of age and arterial oxygen tension revealed a trend toward worsening hypoxemia with diminishing age from 6 to 2 years, which was not identified by clinical scoring. We conclude that clinical scoring is inaccurate for the assessment of hypoxemia in the pediatric age group. Arterial blood gas determination should be used to assess the severity of hypoxemia in the emergency treatment of pediatric asthma patients.