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Biomedical subjects

W F McManus

Publications and source records attributed to W F McManus.

At least 19 recordsLinked to original sources
PubMed1998

An evaluation of the Weber classification of ankle fractures.

This retrospective study over a 3 year follow-up was designed to establish the significance of the Weber classification of ankle fractures with regards to functional and radiographic outcome. One hundred and seven patients were available for follow-up, of which 88 ankles could be classified with the Weber system. Medial malleolar fractures alone and pilon fractures could not be classified with this system. A correlation was found between the type of Weber fracture and the overall ankle score. This held true for unimalleolar fractures alone. More complex bimalleolar and trimalleolar fractures did not follow this convention. Logistical regression analysis was used to evaluate other predictors of outcome. Bimalleolar and trimalleolar fractures were statistically significant predictors of a poorer outcome (P = 0.033, P = 0.021). The initial degree of displacement was also determined to be a predictor of outcome (P = 0.0133) as was the operative reduction (P = 0.0113). Using linear regression, older age (> 62 years) was also established as a predictor of a poorer outcome (P < 0.05). The Weber classification was found to be a predictor of outcome in unimalleloar ankle fractures and not for multimalleolar fractures. We have identified further predictors of a poorer outcome in ankle fractures as the degree of initial injury, the number of malleoli fractured and older age. These factors were found to have greater significance in predicting outcome than the level of fibular fracture alone. We have identified a deficiency of the Weber system in excluding these criteria and have addressed this by modifying the existing system to include the number of malleoli involved, thus providing a more useful prognostic tool.

Adolescent↗
PubMed1996

Aeromonas bacteraemia in burn patients.

Human aeromonas infection is uncommon and is usually associated with immunosuppression, chronic disease or trauma in an aquatic setting. Burn injury may induce a state of immunosuppression, making the thermally injured patient a suitable host for aeromonas infection. We reviewed the experience of one burn centre with this pathogen. Retrospective examination of blood culture results from 8151 patients admitted between 1959 and 1994 disclosed eight patients with clinically relevant Aeromonas hydrophilia bacteraemia. Five were burned outside the USA. Aquatic exposure was known or suspected in only three cases. Five of the eight patients died. Aeromonas infection in burn patients is rare but may occur in the absence of aquatic exposure.

Adult↗
PubMed1996

Effect of ambient temperature on metabolic rate after thermal injury.

OBJECTIVE: The authors describe the effect of ambient temperature on metabolic rate after thermal injury. SUMMARY BACKGROUND DATA: Thermal injury induces a hypermetabolic state, which is reported to increase with the extent of burn. The magnitude of this response is further influenced by ambient temperature. METHODS: The resting energy expenditure was measured by indirect calorimetry at ambient temperatures of 22, 28, 32, and 35 C. It was indexed to a calculated basal metabolic rate in normal volunteers and adult patients with burns involving at least 20% of the total body surface area who had no evidence of systemic infection. These measurements were performed between postburn days 6 and 21. RESULTS: The effect of ambient temperature on metabolic rate was measured in 44 burn patients and 8 normal volunteers. Burn size ranged from 20 to 97% total body surface area with a mean of 44 +/- 18.5% total body surface area. Metabolic rate did not change significantly in control subjects as ambient temperature was varied (p<0.05). Regression analysis showed that burn size and ambient temperature were significant determinants (p<0.01) of metabolic rate in the patients and that together these factors accounted for 55% of the variation observed (df adj. r(2)=0.55) across the range of ambient temperatures studied. Metabolic rate was independent of burn size at ambient temperatures of 32 and 35 C (p<0.02) and increased by a factor of 1.5 X basal metabolic rate. A further increase in metabolic rate, which was positively correlated with burn size, resulted from nonshivering thermogenesis at ambient temperatures 28 and 22 C. The magnitude of this response was greatest at 22 C. CONCLUSIONS: These findings suggest that the hypermetabolic response to thermal injury is maximal in burns as small as 20% total body surface area and that an additional burn size-dependent increase in metabolic rate results from heat loss at ambient temperatures below thermoneutrality.

Adult↗
PubMed1995

Thermal trauma resulting from motor vehicle operation or maintenance.

Burn injury may result from the operation or maintenance of motor vehicles. We reviewed the experience of one burn center with injuries related to motor vehicle use over the 6 year period 1987-1992. One hundred and fifty patients with motor vehicle related burns were identified comprising 11.3% of all admissions for this period. The mean extent of burn injury was 22.8% total body surface area with a mean full thickness (third degree) burn size of 11.7%. The average hospital length of stay was 42.41 days. The most common mechanisms of injury were collisions resulting in fire (n = 48), carburetor priming (n = 37) and scalding from radiator fluid contact (n = 27). Burns resulting from vehicle operation or maintenance are costly and potentially preventable.

Accidents, Traffic↗
PubMed1995

Peritoneal lavage in the diagnosis of acute surgical abdomen following thermal injury.

Intraperitoneal sepsis is difficult to diagnose in thermally injured patients. We reviewed the use of diagnostic peritoneal lavage (DPL) in burn patients suspected of having intraperitoneal infection. Seventeen patients were identified in whom celiotomy, autopsy, or complete recovery could be used to validate the lavage results. A lavage was considered positive if there were greater than 500 white blood cells per mm3 or if microorganisms were present on Gram stain. Six patients had a positive DPL and 11 patients had a negative DPL. There were six true positive, no false positive, ten true negative, and one false negative studies resulting in a sensitivity of 0.86, specificity of 1.00, and diagnostic accuracy of 94%. No complications related to the DPL occurred. This procedure is safe and will rapidly and reliably discriminate between patients needing urgent celiotomy and those requiring further investigation to identify a source of sepsis.

Abdomen, Acute↗
PubMed1995

Burn center care for patients with toxic epidermal necrolysis.

BACKGROUND: Toxic epidermal necrolysis (TEN) is a life threatening exfoliative disorder that is most commonly precipitated by the administration of a medication. Efforts to reduce morbidity and improve survival have brought into question the use of corticosteroids and recommend the transfer of patients to a burn center to facilitate wound care. STUDY DESIGN: This study evaluated the correlation of measures of disease severity and impact of treatment strategies on morbidity and mortality in patients with TEN. The records of all patients with TEN admitted to the United States Army Institute of Surgical Research during a 12 year period were reviewed. Patient characteristics, etiologic agents, time to referral of patients to the burn center, corticosteroid therapy, and other demographic features were studied. Univariate and multivariate analyses were used to determine the significance of these factors with respect to outcome. RESULTS: The sulfonamides and phenytoin were the most frequently identified etiologic agents. Patients at the extremes of age had a higher mortality rate. The period of hospitalization was longer in patients transferred to the burn center more than seven days after skin slough. Percent of epidermalysis, white blood cell count nadir, and corticosteroid administration for more than 48 hours were independently associated with mortality. CONCLUSIONS: These data indicate that the sulfonamides and phenytoin are the most common etiologic agents, expeditious transfer to a burn center reduces morbidity, and corticosteroid administration dramatically increases mortality.

Adrenal Cortex Hormones↗
PubMed1994

A decade of reduced gram-negative infections and mortality associated with improved isolation of burned patients.

OBJECTIVE: To compare the incidence of gram-negative bacteremia (GNB) and mortality in patients with large burns (> or = 20% of total body surface) hospitalized in either an open ward (OW) or a single-bed isolation (IW) environment. DESIGN: Retrospective cohort study. SETTING: The US Army Institute of Surgical Research, Burn Center, Ft Sam Houston, Tex. PATIENTS: Two thousand five hundred nineteen consecutive patients with large burns divided into two 10-year cohorts. Patients in the first cohort period were treated under OW conditions; patients in the second cohort period, under IW conditions. Infection (bacteremia) data were from a laboratory database. A microbial surveillance system was used to monitor patient isolation. Mortality was compared with predicted mortality derived by logistic regression of outcome, burn size, and age of patients without bacteremia in the study. MAIN OUTCOME MEASURES: Presence of GNB and survival. RESULTS: The incidence of GNB was higher in the OW cohort (31.2%) than the IW cohort (12.0%) (P < .001). The postinjury time of first GNB was delayed in the IW vs the OW cohort (28.9 days vs 11.8 days, respectively) (P < .001). For patients who had GNB in the OW cohort, mortality was higher than predicted (observed-predicted mortality ratio, 1.61) (P < .001). Such increased mortality was not present in the IW cohort. Multiple antibiotic-resistant gram-negative pathogens were endemic in the OW cohort. There was no evidence of cross infection or endemic conditions with multiple antibiotic-resistant gram-negative pathogens in the IW cohort. CONCLUSION: Improvements in isolation of burned patients were associated with decreased incidence of GNB, delayed postinjury time of GNB, and improved survival. Improved survival is likely related to decreased susceptibility as a result of longer exposure to the benefits of treatment and wound closure. These results suggest that, in patients with severe burn injuries, gram-negative infections and the related mortality can largely be prevented.

Adult↗
PubMed1994

Insulin-like growth factor-1 lowers protein oxidation in patients with thermal injury.

OBJECTIVE: The effect of insulin-like growth factor-1 (IGF-1) on energy expenditure and protein and glucose metabolism in a group of patients with thermal injury was determined. SUMMARY BACKGROUND DATA: Accelerated protein catabolism is a constant feature of the hypermetabolic response to thermal injury. Insulin-like growth factor-1 has been reported to minimize protein catabolism and normalize energy expenditure in animal models of thermal injury. METHODS: To determine the efficacy of IGF-1 in human burn patients, resting energy expenditure (metabolic cart), whole body protein kinetics (N15 Lysine), and glucose disposal (glucose tolerance test) were assessed in eight burn patients before and after a 3-day infusion of IGF-1 (20 micrograms/kg/hr). All patients were fluid-resuscitated uneventfully and were without obvious infection at the time of study. Enteral nutrition was administered at a constant rate before and during the IGF-1 infusion. RESULTS: Resting energy expenditure was not altered by IGF-1 (40.3 +/- 2.2 vs. 39.1 +/- 2.3 kcal/kg/day). However, glucose uptake was promoted, and protein oxidation decreased significantly (0.118 +/- 0.029 vs. 0.087 +/- 0.021 g/kg/d, p < 0.05) by IGF-1. In addition, insulin secretion, in response to a glucose challenge, was blunted. CONCLUSIONS: Insulin-like growth factor-1 therapy has a beneficial effect in preserving lean body mass during severe stress conditions by minimizing the flux of amino acids toward oxidation.

Adult↗
PubMed1994

Intracompartmental sepsis in burn patients.

An uncommon cause of sepsis in patients with large burns is occult intracompartmental infection. A multi-institution review of 1171 burn admissions identified 5 patients (0.4%) who developed intracompartmental sepsis presenting with fever and purulent drainage or fever, erythema, and swelling on clinical examination. Contributing factors may have included high-volume resuscitation, delayed escharotomy, extravasated intraosseous infusion, cannulation-related arterial injury, and splinting or positioning difficulties. A high index of suspicion and an aggressive surgical approach facilitate successful management of this unusual problem.

Adult↗
PubMed1994

Comparison of acid neutralizing and non-acid neutralizing stress ulcer prophylaxis in thermally injured patients.

We have compared the effectiveness of non-acid neutralizing stress ulcer prophylaxis (SUC) with sucralfate (n = 48) with that of acid neutralizing prophylaxis (AN) utilizing antacids and cimetidine (n = 48) in the prevention of stress ulcer bleeding and nosocomial pneumonia (PN) in thermally injured patients. In the subset of intubated patients, the incidence of PN was 17.8% and 42.8% in the AN and SUC groups, respectively (p < 0.05) despite a similar postburn time of onset of pneumonia. Ten patients in each group died. Three patients in the SUC group developed upper GI bleeding with one requiring gastrectomy. Bacterial colonization of the upper airway occurred in virtually all patients, whereas 83% (SUC) and 96% (AN) had colonization of gastric contents. Gram-negative colonization rates for the upper airway were not different (70%) whereas 48% of SUC patients compared with 60% of AN patients had gram-negative gastric colonization. In conclusion, SUC therapy was efficacious in the prevention of stress ulcer bleeding but did not alter the rate of bacterial colonization of the airway or gastric contents, and was associated with a higher incidence of nosocomial pneumonia in intubated patients.

Adult↗
PubMed1994

A longitudinal study of resting energy expenditure in thermally injured patients.

We have recently developed a new burn-specific equation that satisfactorily estimates initial caloric requirements for thermally injured patients. In the present study, we compared these estimates with resting energy expenditures (REE) (n = 141) measured weekly by indirect calorimetry in 20 patients between postburn days 3 and 348. In this group, mean initial burn size was 46.7% (range, 21-88) and mean age 31.3 years (range, 19-61). Serial measurements were continued until the burn wounds were closed or the patient was discharged. Multiple regression analysis indicated a relationship between REE, initial burn size, and postburn day in these patients (r = 0.65). This analysis indicated a general trend of decline in REE toward normal values 100 to 150 days postburn in patients with smaller burns (20%-40%) and roughly 250 days postinjury in those with larger burns (> 75%). The initial predictive equation appeared adequate for estimating caloric needs during the first postburn month, but beyond 30 days postburn indirect calorimetric measurements became necessary for accurate estimation of caloric requirements.

Adult↗
PubMed1993

Improved survival of burned patients with inhalation injury.

OBJECTIVE: To study a cohort of patients treated at the same institution and to compare that patient population with that of a previous report documenting the comorbidity of inhalation injury and pneumonia. Specifically, we wanted to determine whether there had been an improvement in survival of patients suffering inhalation injury. DESIGN: A retrospective review. SETTING: The US Army Institute of Surgical Research, Ft Sam Houston, Tex, a 40-bed burn intensive care referral unit. SUBJECTS: One thousand two hundred fifty-six thermally injured patients treated between January 1985 and December 1990. MAIN OUTCOME MEASURE: A comparison of pneumonia frequency and ultimate survival of the current cohort of patients as compared with a previously generated stepwise logistic analysis predicting mortality on the basis of 1980 to 1984 patient data. RESULTS: Of 1256 burned patients admitted between 1985 and 1990, there were 330 identified as having inhalation injury. These patients were older (35.0 vs 26.6 years) and had more extensive burns (41.1% vs 18.3%) and a higher mortality (29.4% vs 5.0%) than did the patients without inhalation injury. When compared with a mortality predictor generated from 1980 through 1984 patient data, patients in the most recent period had a lower mortality than predicted (29.4% vs 41.4%). Patients with less severe injury (positive xenon scan, negative results of bronchoscopy; n = 85), although having a similar incidence of pneumonia (13.1% vs 19.5%) as the same group from 1980 through 1984, accounted for the most improvement in survival. The 3.6% mortality was significantly less than the predicted rate of 15.7%. Patients with positive results of bronchoscopy (n = 245) also showed some improvement in outcome from that predicted (38.3% vs 50.2%) despite no change in the rate of pneumonia (46.9% vs 48.5%). Further improvement in survival was realized in those patients supported with high-frequency ventilation. Although their age (33.9 vs 36.3 years), burn size (46.0% vs 45.5%), and duration of intubation (16.8 vs 15.1 days) were similar to those of conventionally treated patients, mortality was significantly less than predicted (16.4% vs 40.9%) and less than that in patients treated with conventional ventilation (16.4% vs 42.7%). CONCLUSIONS: The improvement in survival of patients with inhalation injury represents the aggregate effects of the general improvement and outcome of all burned patients, the prevention of pneumonia by high-frequency ventilation, and the reduced mortality from the pneumonias that did occur.

Adult↗
PubMed1993

The renal effects of low-dose dopamine in thermally injured patients.

The renal effects of low-dose dopamine (LDD) therapy in hyperdynamic thermally injured patients are unknown. We investigated the renal effects of LDD in ten burn patients (mean +/- SEM age and % total body surface burned: 30.2 +/- 3.3 years and 53.4% +/- 7%) and six controls (mean age; 20.2 +/- 0.5 years). Administration of LDD significantly increased glomerular filtration rate, effective renal plasma flow, sodium excretion, and urine flow in the controls and effective renal plasma flow, urine flow, heart rate, and cardiac index in the patients. The chronotropic effect of dopamine appears to be a principal contributor to the patients' increased effective renal plasma flow. Sodium excretion was increased by LDD only in the patients in whom the predopamine sodium excretion exceeded 5 mEq/h. Lack of a consistent natriuretic effect and the consistent chronotropic effect suggest that the routine use of low-dose dopamine in burn patients is unwarranted. The side effects that attend the desired response determine clinical use, i.e., the potential for blood flow redistribution and increased cardiac work demands must be balanced against increased renal plasma flow and natriuresis.

Adult↗
PubMed1993

Superior mesenteric artery syndrome in a burn patient.

Weight loss resulting from the hypermetabolic response to burn injury is not unusual and is often unavoidable. The loss of retroperitoneal fat has been postulated as a major factor in the cause of the uncommon complication of superior mesenteric artery syndrome. This syndrome is frequently treated nonoperatively with aggressive nutrition support. Nasojejunal feeding past the point of obstruction should be considered as the primary method of nutrition support. Alternatively, total parenteral nutrition or a combination of enteral and parenteral feeding may be necessary to meet nutritional needs until the duodenal obstruction resolves. This case study describes the nutrition management of a burn patient who developed superior mesenteric artery syndrome.

Burns↗
PubMed1993

Wound closure and outcome in extensively burned patients treated with cultured autologous keratinocytes.

Cultured autologous keratinocytes (CAK) have been heralded as a means to achieve more rapid closure of massive burn wounds. Despite the claimed benefits of this technology, we have failed to identify its positive impact on wound closure in extensively burned patients. Sixteen patients with a mean age of 29.7 years (range, 10-56 years) and a mean total body surface area burn of 68.2% (range, 42%-85%) underwent 22 applications of CAK supplied by a private laboratory. The keratinocyte grafts were applied to a mean of 15.9% of the body surface area (range, 4%-59%) at an average cost per patient of $43,705 (range, $9,800 to $161,000). The mean body surface area of definitive wound coverage by these grafts was 4.7% (range, 0%-18.6%). The mean length of hospitalization was 132 days (range, 50-275 days). The observed mortality was 12.5% (two patients). Our experience with this wound care approach has been assessed with respect to the extent of burn, the level of wound excision, and the site of CAK application.

Adolescent↗
PubMed1992

Alterations in intestinal permeability after thermal injury.

Alterations in intestinal permeability have been postulated to occur after thermal injury. We evaluated the status of intestinal permeability during the first 2 postburn weeks in 15 subjects by measuring the differential excretion of enterally administered lactulose and mannitol. The mean age and burn size of the patients were 32.7 +/- 3.6 years and 53.3% +/- 5.1% of the total body surface area, respectively. Ten healthy volunteers were also studied. The lactulose-mannitol excretion ratio was 0.159 +/- 0.017 for the patients and 0.017 +/- 0.003 for controls. The increased ratio did not correlate with burn size or postburn day. Patients who developed significant clinical infections during their first 2 postburn weeks had lactulose-mannitol ratios on postburn day 2 that were significantly higher than those of controls and patients who did not develop infections. This suggests a relationship between susceptibility to infection and early alterations in intestinal permeability.

Adult↗
PubMed1992

Burns in morbidly obese patients.

It has been estimated that 26% of Americans are obese. A very small subset of this group can be categorized as morbidly obese, fulfilling the criteria of being 100 pounds, or 100%, over ideal body weight. The clinical records of seven morbidly obese burn patients treated over a 20-year period are reviewed. Particularly notable was a 43% incidence of fatal pulmonary embolism.

Adult↗