Richard G. Strate

Kinetic model for gentamicin dosing with the use of individual patient parameters

Multiple‐infusion dosing regimens for gentamicin were established for 84 patients with the use of individually calculated values of elimination kinetic parameters. Serum level‐time data obtained after a single infusion were used to determine the patients gentamicin half‐life (t½) and distribution volume. Patients with serum creatinine (Cr) <1.2 mg per 100 ml had t½s (mean, 2.25 hr) and total body clearances (mean, 0.082 L/hr/kg) significantly different from those with Cr ≥1.2 mg/100 ml (means, 5.3 and 0.039, respectively). Distribution volumes were not significantly different (means, 0.22 and 0.21 L/kg, respectively). Calculations of dosing intervals and infusion rates, based on each patients kinetic parameters and desired steady‐state peaks and nadirs, assumed a one‐compartment model with first‐order elimination and 1‐hr constant‐rate input at fixed intervals. Follow‐up steady‐state peak and nadir levels were measured in 63 of the regimens. Differences between predicted and measured peak levels averaged ‐0.05 µg/ml with 60% of the measured values falling within 1 µg/ml of that predicted. Predicted‐measured nadir differences averaged −0.62 µg/ml (significantly different from zero) indicating slight bias in the model. Fifty‐six percent of these nadirs were within 1 µg/ml of that predicted.

The natural history of electrical injury.

The natural history of electrical injury, exclusive of electrical flash burns, was determined in 64 patients. These patients sustained relatively small burns (x=11%); only nine patients (14%) had burns greater than 25%. Forty-six patients suffered 114 major complications. EKG abnormalities occurred in 36%, including major cardiac arrhythmias in ten patients. One-fourth of the patients developed neurologic sequelae (CNS-8, peripheral-8). Electrical vascular injury with subsequent arterial occlusion was responsible for many of the major amputations. Nineteen patients required 32 amputations (digits-17, hand-1, foot-2, leg-3, arm-9). Early patient referral and vigorous fluid resuscitation minimized renal failure (1.5%) and mortality (3.1%). Early fasciotomy and vigorous debridement appeared to decrease wound sepsis (8%), but apparently had little if any effect on major limb salvage. The unsolved problems of electrical injury, namely neurological and vascular sequelae, are major contributors to the high morbidity of electrical injury.

Increased dosage requirements of gentamicin in burn patients.

In 14 burn patients treated for serious Gram-negative infections, the use of the previously recommended gentamicin dose of 5 mg/kg/day was found to result in subtherapeutic serum concentrations (peak concentration less than 4 mg/L). The gentamicin half-life was found to be unusually short especially in the younger burn patients. Because of this shorter half-life the dosage interval was decreased to 4 hours to prevent extended periods of subtherapeutic serum concentrations. In addition, the daily dose of gentamicin was increased to achieve therapeutic peak concentration. Individualizing each patients gentamicin regimen was thought to be instrumental in the favorable response of two patients with Pseudomonas ecthyma gangrenosum. The results of this study would strongly support the measurement of serum gentamicin levels in all burn patients with life-threatening infection. The gentamicin dosage regimen should then be individualized for each patient to provide optimal peak concentrations. In addition, patients demonstrating a short drug half-life may require a decreased dosage interval to prevent prolonged periods of sub-therapeutic concentrations.

Diagnostic peritoneal lavage in blunt abdominal trauma.

: Diagnostic peritoneal lavage is accurate and safe. It leads to fewer unnecessary laparotomies than if clinical examination alone is used and nearly eliminates deaths from undiagnosed abdominal injuries. Persons with clinical abdominal findings, shock, altered sensorium, and severe chest injuries after blunt trauma should undergo the procedure.

Open pelvic fracture: a lethal injury.

Twenty-two of 604 patients (4%) with pelvic fracture (PF) had open fractures. Eight per cent of all pedestrian and motorcycle accidents resulted in open PF, compared to 0.8% of all vehicular accidents. With one exception, all patients sustained multiple injuries. The mortality rate for an open PF was 50%, in marked contrast to 10.5% for a closed PF. Of more importance, the pelvic fracture was the primary cause of death in 73% of those dying with an open PF and in 30% of those dying with a closed PF. The higher mortality is due to an increased risk of infection and to massive hemorrhage because of a high risk of concomitant major vessel injury, as well as increased diffuse retroperitoneal hemorrhage, in these open fractures. Therapy directed to restoring blood volume, identifying and repairing major vessel injury, and attempting to decrease the diffuse retroperitoneal hemorrhage is essential. If drainage is necessary, it should be accomplished with a closed system. Immediate colostomy and use of antibiotics should decrease the infectious complications.

Blunt trauma in adults and children: a comparative analysis

Trauma remains the major cause of death in children and young adults. Adult and pediatric patients differ significantly in both mechanism of and physiologic response to injury. We reviewed the records of all consecutive adult and pediatric blunt trauma patients admitted to a major metropolitan trauma center for a 10-year period. An extensive computerized database has been maintained for all patients since 1977. A comparative statistical analysis of mechanism of injury, specific organ injury, and clinical outcome was performed. Altogether, 1,722 adults and 289 children were treated during the study period. Blunt trauma accounted for 82.8% of adult and 94.3% of pediatric injury (p = 0.00005), and only these patients were considered for analysis. Diagnostic peritoneal lavage was performed in 249 children and 1,464 adults, with a respective accuracy of 99.6% and 97.2%. Mechanism of injury was comparable for both groups, although children were far more likely to be injured by falls, bicycle accidents, or struck by an automobile. Comparative analysis of specific injuries demonstrated significantly fewer pediatric chest (p = 0.001), spine (p = 0.03), and pelvic (p = 0.003) injuries. Central nervous system (CNS) injury in children was a strong determinant of outcome: serious pediatric CNS trauma was associated with a tenfold increase in mortality. Mortality for children in the absence of CNS injury was less than 3%. Spinal injury also appeared to be a predictor of poor outcome in the pediatric population, with an associated mortality of greater than 50%. Overall, survival was age independent (82.5% of adults and 85.8% of children were survivors.(ABSTRACT TRUNCATED AT 250 WORDS)

The management of human bite injuries of the hand.

Three hundred twenty-seven bite injuries of the hand were reviewed for incidence of infectious complications. A policy to hospitalize all patients with human bite injuries was maintained, but noncompliance was high. Patients with uninfected or superficially infected bites (131) were hospitalized and treated with parenteral penicillin, cephalosporins, or clindamycin (mean duration, 45 hours). Among the 62 patients not lost to followup three minor septic complications occurred. Of similar patients not hospitalized (134), only two thirds received antibiotic therapy but no complications were observed. These data suggest that human bite hand infections can be averted and that established superficial infections can be successfully treated with outpatient antibiotic therapy. Of the 62 patients with moderately to severely infected human bites, 77% were injured by striking an opponent; 52% suffered injury over metacarpophalangeal joints. The mean delay in seeking medical attention was 2 1/2 days, compared to 1/2 day in the less severely infected group. Of the patients with more seriously infected bites, 94% received parenteral antibiotic therapy. Of 30 patients with known outcome in the latter group 27% suffered complications (stiffness; recurrent infection; other infectious complication), confirming the high morbidity of established deep hand infections secondary to human bites.

The salvageability of patients with post-traumatic rupture of the descending thoracic aorta in a primary trauma center.

If uniform early diagnosis is accomplished, two thirds of patients with rupture of the proximal descending aorta seen at a primary trauma treatment center are potentially salvageable. Currently the survival rate is only one half of this optimum figure (31%). One third of 39 patients with acute rupture of the proximal descending thoracic aorta studied had lethal concomitant injuries and were unsalvageable. Twenty-six patients were potentially salvageable; twelve (46%) survived. Eight potential survivors (31%) died because their aortic rupture was not diagnosed or because it was not promptly diagnosed. Eighteen of the potentially salvageable patients (69%) underwent aortic repair; two thirds survived. Aortic rupture was uniformly diagnosed earlier in the more critically injured patients and thus they underwent aortic repair earlier. One half of the 12 patients in whom thoracotomy was instituted within 6 hours of admission survived; six patients who underwent aortic repair more than 6 hours after admission survived.

Blunt injury to the colon and rectum

One hundred nine patients suffering blunt injury to the colon or rectum were treated between 1 January 1970 and 31 December 1980. Vehicular accidents accounted for 90% of the injuries and 91% of the fatalities. Multiple system injury predominated, with survivors averaging 1.9 and nonsurvivors 3.8 injuries/patient. Six cases were complicated by abdominal sepsis directly related to their colon injury. There were no deaths and no episodes of colon-related abdominal sepsis among patients with isolated colon trauma. Of the 32 patients not surviving, four (3.7%), died as a direct result of their colon injury. Three of the four deaths appear to have been preventable.

Brachial Artery Disruption following Closed Elbow Dislocation

Although elbow dislocation occurs frequently, associated brachial artery injury is rare. Adequate treatment of this injury includes prompt arteriography, reduction of the dislocation, vascular repair, and transarticular fixation of the reduction. A case report and review of the literature are presented.