PubMed Health⌕ Search

Biomedical subjects

B A Pruitt

Publications and source records attributed to B A Pruitt.

At least 37 records · Page 2Linked to original sources
PubMed1998

Inhaled nitric oxide prevents left ventricular impairment during endotoxemia.

We evaluated the effect of long-term inhalation of nitric oxide (NO) on cardiac contractility after endotoxemia by using the end-systolic elastance of the left ventricle (LV) as a load-independent contractility index. Chronic instrumentation in 12 pigs included implantation of two pairs of endocardial dimension transducers to measure LV volume and a micromanometer to measure LV pressure. One week later, the animals were divided into a control group (n = 6) or a NO group (n = 6). All animals received intravenous Escherichia coli endotoxin (10 micrograms. kg-1. h-1) and equivalent lactated Ringer solution. NO inhalation (20 parts/million) was begun 30 min after the initiation of endotoxemia and was continued for 24 h. In both groups, tachycardia, pulmonary hypertension, and systemic hyperdynamic changes were noted. The end-systolic elastance in the control group was significantly decreased beyond 7 h. NO inhalation maintained the end-systolic elastance at baseline levels and prevented its impairment. These findings indicate that NO exerts a protective effect on LV contractility in this model of endotoxemia.

Administration, Inhalation↗
PubMed1997

The use of perfluorocarbon-associated gas exchange to improve ventilation and decrease mortality after inhalation injury in a neonatal swine model.

Patients with tracheobronchial disease frequently require mechanical ventilation during therapy and experience iatrogenic complications such as barotrauma and volutrauma. The purpose of this study was to determine whether perfluorocarbon-associated gas exchange (PAGE) results in lower ventilatory pressures and more efficient ventilation than that provided by conventional ventilation after tracheobronchial mucosal injury caused by smoke inhalation in neonatal piglets. Ten piglets were used for this prospective, randomized study. After administration of a severe smoke inhalation injury, the piglets were randomly assigned to either the perfluorocarbon or control groups. Group 1 served as the control population and received standard (time-cycled, volume-limited) mechanical ventilation. Ventilator settings were adjusted to maintain physiological pH and PO2 at the lowest tidal volume, rate, and end-expiratory pressure possible throughout the study period. Group 2 was administered intratracheal perfluorocarbon as well as identical mechanical ventilation to attain the same physiological pH and PO2. Oxygenation index, peak and mean airway pressures, and arterial blood gas levels were measured throughout the study period and subjected to statistical analysis. Histological comparison of airway and parenchymal tissues confirmed identical patterns of smoke injury in both groups. Carbon monoxide levels were the same in both groups. There was significant barotrauma and volutrauma in the control group, but none in the PAGE group. All controls died from 13 to 17 hours after injury; one PAGE pig died at 23 hours with all others surviving past 24 hours (P = .0021). Peak, plateau, and mean airway pressures were all significantly higher (P < .05) past 12 hours after injury and continued to increase until death in the controls. Arterial blood gases showed significantly (P < .05) decreased pH, PO2, and elevated PcO2 levels in the control group past 12 hours after injury. The oxygenation index was significantly elevated (P < .05) in the control group past 12 hours after injury. PAGE shows potential for improving ventilation and survival immediately after severe smoke inhalation injury and may have clinical applications in other nonhomogeneous lung injuries.

Animals↗
PubMed1997

Incidence of bacteremia after burn wound manipulation in the early postburn period.

BACKGROUND: Transient bacteremia associated with burn wound manipulation is considered a frequent occurrence and is commonly cited as an indication for perioperative antibiotic prophylaxis in burn patients. METHODS: In a prospective clinical setting, blood cultures (BC) were obtained from 19 burn patients at the following intervals: 30 minutes before wound cleansing (WC) or wound excision (WE), 30 minutes after the start of WC or WE, hourly until procedure completion, and 1 hour after completion. Burn wound biopsy for histologic grading and microbial culture was performed after the first BC. RESULTS: Twenty-two WC and 20 WE episodes were evaluated by 67 and 76 BC sets, respectively. Patients had a mean age of 42.8 years and mean burn size of 50% of the body surface area. Three WC episodes (13.6%) and four WE procedures (20.0%) were associated with postprocedure bacteremia. Two patients had both preprocedure and postprocedure bacteremia later attributed to nonburn wound infections. Excluding these cases, the bacteremia rate was 12.5% (9.5% from WC and 15% from WE). Wound biopsy culture and histologic analysis did not predict the occurrence of bacteremia. CONCLUSION: Current therapy is associated with a lesser incidence of burn wound manipulation-induced bacteremia than reported in prior series. The discordance between wound biopsy and BC results, the absence of positive histology, and the similarity of bacteremia occurrence rates with WC and WE confirm the effectiveness of current techniques of microbial control in burn wounds and question the need for perioperative antibiotic therapy in patients with burns involving less than 40% of the total body surface during the first 10 postburn days.

Adult↗
PubMed1997

Effects of burns on inhalation injury.

BACKGROUND: There are few studies of smoke injury combined with thermal burn. METHODS: Seven sheep (G1) received smoke injury alone; eight (G2) received a 40% full-thickness scald burn immediately after smoke injury. All animals were resuscitated with lactated Ringer's solution and killed 48 hours after injury. Cardiopulmonary variables and blood gases were measured serially. Ventilation perfusion distribution was analyzed using the multiple inert gas elimination technique. Lung wet to dry weight ratio and malondialdehyde levels were determined. RESULTS: G2 resulted in early significant hemodynamic changes. Serum total protein concentration was significantly lower and malondialdehyde significantly higher in G2. However, PaO2, lung wet to dry weight ratio, and ventilation perfusion mismatching in G2 did not differ from those in G1. CONCLUSIONS: Although the addition of burn injury exaggerated the lung lipid peroxidation and hypoproteinemia in the presence of more pronounced hemodynamic changes, the pulmonary dysfunction was not accentuated.

Animals↗
PubMed1997

Optimized mesh expansion of composite skin grafts in rats treated with direct current.

BACKGROUND: The purpose of this study was to determine the optimum autoepidermal and allodermal expansion ratio of each component of a meshed composite skin graft (MCSG) that would lead to successful healing. METHODS: Male Sprague-Dawley rats were used as hosts of the MCSG and donors of autologous tissue. Male ACI rats were used as donors of allodermis. MCSGs with open meshed area (autoepidermal/allodermal) of 9:1/1.5:1, 9:1/3:1, 9:1/6:1, or 6:1/6:1 were applied to full-thickness skin defects and treated with a silver nylon dressing (SN) or SN with direct current (DC). Wound size, hair regrowth, and thickness of dermal layer were evaluated at 3 months. RESULTS: MCSGs of 9:1/1.5:1, 9:1/3:1, and 6:1/6:1 mesh ratios healed completely within 3 months with no difference in wound size between SN dressing groups or DC-treated groups. Application of DC reduced MCSG contraction and stimulated regrowth of hair. CONCLUSION: Fresh autoepidermis can be expanded 6:1 on a 6:1 allodermis or 9:1 on a 3:1 allodermis and achieve successful wound healing.

Animals↗
PubMed1997

Prospective outcome analysis of a protocol for the surgical and rehabilitative management of burns to the hands.

Treatment protocols for the management of burned hands are essential for integrating team efforts and achieving optimal functional results. Standard protocols are especially useful during mass casualty incidents, when the admission of multiple patients with large burns and/or associated injuries may reduce the priority usually accorded the hands. We prospectively evaluated a surgical and rehabilitative treatment protocol for burned hands during a mass casualty incident, after which 43 burn patients with 82 burned hands were admitted to one burn center. Soft-tissue management was individualized to achieve, if possible, wound closure within 14 days, and included the use of topical antimicrobials, cutaneous debridement and/or tangential excision, biologic dressings, and split-thickness autografts. Range of motion therapy was based on daily measurement of active motion of the metacarpophalangealjoints. Static splinting alternating with continuous passive motion every 4 hours was utilized for sedated patients. Continuous passive motion alternating with active ranging and night splinting was utilized for metacarpophalangeal flexion <70 degrees. Active ranging and progressive resistance was utilized for metacarpophalangeal flexion > or =70 degrees. Sixty-four hands required excision and grafting, with 89 percent having at least one autografting procedure completed by postburn day 16. Total active motion of the hands treated averaged 220.6 degrees on discharge and 229.9 degrees at 3 months after injury. Mean hand grip strength was 60.8 pounds at discharge and 66.0 pounds at 3 months after injury. Adherence to a standard hand burn protocol resulted in timely wound coverage and recovery of hand function for a large group of patients treated at a single burn facility after a mass casualty incident.

Accidents, Aviation↗
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↗
PubMed1996

Direct current reduces wound edema after full-thickness burn injury in rats.

OBJECTIVE: To observe the effect of 4 and 40 microA direct current (DC) on edema formation after burn injury in rats. DESIGN, MATERIALS, AND METHODS: Silver-nylon wound dressings were used as either anodes (-) or cathodes (+) on 20% total body surface area full-thickness scalds in anesthetized male Sprague-Dawley rats. Untreated burned rats and rats treated with silver-nylon dressings without current were used as controls. MEASUREMENTS AND MAIN RESULTS: Immediately applied, continuous DC reduced burn edema by 17 to 48% at different times up to 48 hours postburn (p < 0.001). Neither reversal of electrode polarity nor change in current density had any significant effect on the results of treatment. Starting treatment during the first 8 hours postburn produced the least edema accumulation, but the reduction was significant even when DC was applied 36 hours afterburn. If started immediately after injury, treatment had to be continued a minimum of 8 hours to be most effective. CONCLUSIONS: Direct electric current has a beneficial effect in reducing wound edema after burn injury.

Animals↗
PubMed1996

Direct current reduces plasma protein extravasation after partial-thickness burn injury in rats.

OBJECTIVE: To observe the effect of 40 microA direct current (DC) on plasma albumin extravasation after burn injury. DESIGN, MATERIALS, AND METHODS: Silver-nylon wound dressings were used as anodes (-) on anesthetized male Sprague-Dawley rats with 20% total body surface partial-thickness scald burns. Burned rats with no treatment, or treated with silver-nylon dressing without current, were used as controls. Quantitative analysis of fluorescein isothiocyanate (FITC)-albumin leakage and accumulation in the wound tissue was performed using confocal fluorescence microscopy. MEASUREMENTS AND MAIN RESULTS: In controls, the rate of albumin leakage was maximal at 1 hour postburn (PB) and then decreased, but remained higher than normal for 48 hours PB. The accumulation of FITC-albumin was maximal 4 to 6 hours PB and substantial for 48 hours. When DC was applied, leakage was reduced by 30 to 45% and approached normal control rates by 8 hours PB. FITC-albumin concentration peaked 4 hours PB, was 18 to 48% less then in burned control, and approached the level observed in unburned control by 18 hours PB. CONCLUSIONS: DC has a beneficial effect in reducing plasma protein extravasation after burn injury.

Animals↗
PubMed1996

Cardiopulmonary effects of combined nitric oxide inhibition and inhaled nitric oxide in porcine endotoxic shock.

BACKGROUND: Nitric oxide synthase (NOS) inhibition has been shown to potentiate lipopolysaccharide (LPS) associated pulmonary hypertension, which may worsen right ventricular (RV) dysfunction and decrease cardiac output during sepsis. This study evaluates whether inhaled nitric oxide can ameliorate the adverse cardiopulmonary effects of NOS inhibition during endotoxemia. METHODS: After an infusion of Escherichia coli LPS (200 micrograms/kg), animals were resuscitated with saline (1 mL/kg/min) and observed for 3 hours while mechanically ventilated (FIO2, 0.6; VT, 12 mL/kg; positive end-expiratory pressure, 5 cm H2O). The LPS group (n = 6) received no additional treatment. The N-nitro-L-arginine methyl ester (NAME) group (n = 5) received L-NAME, a NOS inhibitor, 50 micrograms/kg/min for the last 2 hours. The NO+NAME group (n = 6) received inhaled NO (40 ppm) and L-NAME for the last 2 hours. The control group (n = 5) received only saline without LPS. Hemodynamic data and blood gases were collected hourly for 3 hours. RESULTS: L-NAME worsened LPS-associated pulmonary hypertension and RV dysfunction as reflected by decreased RV ejection fraction. Inhaled nitric oxide significantly decreased pulmonary hypertension and improved RV ejection fraction and stroke work index. There were no adverse systemic effects. CONCLUSIONS: Inhaled nitric oxide reverses pulmonary hypertension seen with L-NAME treatment during endotoxemia and may be a useful adjunct to NOS inhibition in the treatment of septic shock.

Administration, Inhalation↗
PubMed1996

Ventilation-perfusion alterations after smoke inhalation injury in an ovine model.

To study the pathophysiological mechanism of progressive hypoxemia after smoke inhalation injury, alterations in ventilation-perfusion ratio (VA/Q) were studied in an ovine model by using the multiple inert gas elimination technique. Because ethane was detected in expired gas of some sheep, we replaced ethane with krypton, which was a unique application of the multiple inert gas elimination technique when one of the experimental gases is present in the inspirate. Severity-related changes were studied 24 h after injury in control and mild, moderate, and severe inhalation injury groups. Time-related changes were studied in controls and sheep with moderate injury at 6, 12, 24, and 72 h. Arterial PO2 decreased progressively with severity of injury as well as with time. In smoke-exposed animals, blood flow was recruited to low VA/Q compartment (0 < VA/Q < 0.1; 17.6 +/- 10.6% of cardiac output, 24 h, moderate injury) from normal VA/Q compartment (0.1 < VA/Q < 10). However, increases in true shunt (VA/Q = 0; 5.6 +/- 2.5%, 24 h, moderate injury) and dead space were not consistent findings. The VA/Q patterns suggest the primary change in smoke inhalation injury to be a disturbance of ventilation.

Airway Resistance↗
PubMed1996

Update on current therapeutic approaches in burns.

Burn injury results in a rapid loss of intravascular volume as wound edema forms, which reduces the circulating blood volume and generates the need for fluid therapy to combat hypovolemia. Fluid resuscitation of a burn patient is usually carried out with isotonic, sodium- and chloride-containing fluids, such as lactated Ringer's solution. The initial 24 h resuscitation volume is based on the burn size and body weight of the patient. Following a successful resuscitation, the burn patient develops stereotypic neurohormonal and metabolic responses that, depending on the extent of injury, last for several weeks or months. Breathing of incomplete products of combustion by the fire victim produces inhalation injury, the incidence of which rises with increasing burn size and the severity of which is proportional to the duration of exposure. Systemic hypoxia from carbon monoxide toxicity causes early death; chemical airway injury increases mortality and predisposes to subsequent pneumonia that further reduces survival. The diagnosis of inhalation injury is made by bronchoscopy and/or xenon scan and therapy involves support of ventilation. Thermal destruction of the cutaneous mechanical barrier and the presence of nonviable avascular burn eschar as well as impairment of other host defenses render the burn patient susceptible to local as well as systemic infections. Care following resuscitation is focused on topical antimicrobial therapy, burn wound excision, and wound closure by grafting. Nutritional support and the prevention and control of infection are constant themes in burn patient management. A progressive improvement in general care of the acutely injured patient, prevention of shock, effective means of maintaining organ function, prevention and control of burn wound and other infections, and physiologically based metabolic support have significantly increased burn patient survival in recent decades.

Burns↗
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

Effects of inhaled nitric oxide on right ventricular function in endotoxin shock.

Sepsis has been shown to cause right ventricular (RV) dysfunction, which may be related to pulmonary hypertension and increased RV afterload. This study evaluates the effects of inhaled nitric oxide (NO), a selective pulmonary vasodilator, on RV function in a porcine model of endotoxemia. After an infusion of Escherichia coli lipopolysaccharide (LPS; 200 micrograms/kg), animals were resuscitated with saline (1 mL/kg/min) and observed for 3 hours while being mechanically ventilated (Fio2 = 0.6, tidal volume = 12 mL/kg, and peak end-expiratory pressure = 5 cm H2O). The LPS group (n = 5) received no additional treatment. The NO group (n = 5) received inhaled NO (40 ppm) for the last 2 hours. The control group (n = 5) received only saline without LPS. Hemodynamic data and blood gases were collected hourly for 3 hours. LPS resulted in pulmonary hypertension and RV dysfunction as indexed by a decreased RV ejection fraction and increased RV end-diastolic volume. Inhaled NO significantly decreased pulmonary hypertension and significantly increased RV ejection fraction and oxygen delivery without adverse effects. In conclusion, inhaled NO significantly improved pulmonary hypertension and RV dysfunction in a porcine model of endotoxemia and should be a useful therapeutic modality in selected septic patients.

Administration, Inhalation↗