Search PubMed⌕ Search

Biomedical subjects

F T Caldwell

Publications and source records attributed to F T Caldwell.

At least 19 recordsLinked to original sources
PubMed1992

Control of the hypermetabolic response to burn injury using environmental factors.

This study was performed to establish the relative efficiency of occlusive dressings and variable ambient temperature (group I) versus no dressings and variable ambient temperature (group II) versus no dressings and electromagnetic heaters (group III) for controlling the postburn hypermetabolic response. Fifteen burn patients and five normal controls (group IV) were studied when subjectively comfortable using partitional calorimetry, after which each patient was cold stressed by sequentially decreasing external energy support, and repeating calorimetry studies and serial plasma catecholamine assays. The percentage increase in heat production above predicted normal values was significantly increased for all groups when cold (C) versus neutral (N) (group I: [N] 24 +/- 24 versus [C] 49 +/- 25%; group II: [N] 46 +/- 35 versus [C] 74 +/- 47%; group III: [N] 21 +/- 20 versus [C] 78 +/- 25%; group IV: [N] -9 +/- 12 versus [C] 16 +/- 10%, p less than 0.05 all comparisons). Plasma catecholamine values did not increase significantly when patients were subjectively cold. These studies do not support the role of catecholamines as the primary mediator in the cause of the postburn hypermetabolic response. Using the patients' subjective comfort status as a guide for external energy support, it is possible to greatly reduce but not to eliminate the hypermetabolic response to burn injury.

Adult↗
PubMed1992

Ibuprofen lowers body temperature and metabolic rate of humans with burn injury.

A group of 15 burned children and young adults with large burns (mean, 41% +/- 15% BSA) were administered ibuprofen (40 mg/kg for 3 days). Each patient served as his or her own control in this crossover study (with and without ibuprofen). Paired calorimetric and temperature studies and urinary nitrogen measurements were performed. No nitrogen-sparing effect was identified for this dose of ibuprofen. However, patients demonstrated a statistically significant reduction in average rectal temperature (0.67 degrees C decreases) (p less than 0.01) and in metabolic rate (11.4% decreases) (p less than 0.01) while taking ibuprofen. Linear regression analysis of the reduction in temperature versus the reduction in metabolic rate yielded a statistically significant correlation (p less than 0.01) with a slope of 13.6% reduction in metabolic rate per degree centigrade reduction in the 72-hour average rectal temperature. These results support the hypothesis that ibuprofen attenuates the hypermetabolic response to thermal injury by blunting the temperature elevation that is usually seen.

Adolescent↗
PubMed1990

Effect of early feeding on the postburn hypermetabolic response in rats.

The effect of early enteral feeding on the hypermetabolic response following burn injury in a rat burn model has been investigated. The rates of heat production and partitioned heat loss were determined on the fourteenth postburn day for five treatment groups: I) burn, fed rat chow ad libitum starting 2 hours postburn; II) burn, fed by gastrostomy beginning 2 hours postburn; III) burn, fed by gastrostomy, delayed until 72 hours postburn; IV) controls, fed by gastrostomy 2 hours post anesthesia; and V) controls, fed rat chow ad libitum 2 hours post anesthesia. Gastrostomy feedings delivered 175 kcal/kg.day. The mean rates of heat production and heat loss for the three burn groups did not differ significantly whether rats were fed chow ad libitum, or by gastrostomy early or late. Contrary to previous studies using a guinea pig model, method and timing of feeding in this burned rat model had no significant effect on the postburn increment in the rate of heat loss and the corresponding increment in the rate of heat production.

Animals↗
PubMed1988

Surgical complications of thermal injury.

Aggressive control of intragastric pH in the burn patient has essentially eliminated upper gastrointestinal bleeding. The recent spectrum of complications in the thermally injured patient has shifted. Vascular occlusion and missed associated injury were the most frequent early complications in this review. Those complications occurring late in the course were attributed to sepsis originating in the burn wound. The common diagnostic error was to blame the burn injury for the patient's signs and symptoms. A high index of suspicion of an occult process must be exercised when caring for the burn patient who has burn shock with a decreasing hematocrit value or a compartment syndrome that does not respond to escharotomy or fasciotomy or the septic patient with a clean burn wound.

Adolescent↗
PubMed1988

The effect of early feeding on postburn hypermetabolism.

The effect of early enteral feeding upon postburn hypermetabolism was studied on the fourteenth postburn day using five groups of rats. Feeding methods and treatments for the groups were: I) rat chow ad libitum at 2 hours postburn (PB); II) fed early by gastrostomy at 2 hours PB; III) fed late by gastrostomy at 72 hours PB; IV) fed early by gastrostomy--shaved control; V) rat chow ad libitum--shaved control. Gastrostomy feedings delivered 175 kcal/kg.day. The rates of heat production and heat loss did not differ significantly between any of the burn groups, whether fed ad libitum, or early or late by way of gastrostomy. The burned rats fed ad libitum gained significantly more weight than the rats fed late by gastrostomy. Contrary to previous studies using a guinea pig model, method and timing of feeding had no demonstrable effect on the postburn increment in heat loss and the secondary increment in heat production following thermal injury in rats.

Animals↗
PubMed1979

Critical evaluation of hypertonic and hypotonic solutions to resuscitate severely burned children: a prospective study.

Children with thermal burns covering 30% or more of the body surface area were alternately resuscitated with either hypertonic lactated saline (HLS) or lactated Ringer's solution (LRS). Parameters sequentially measured and calculated included: 1) serum and urine electrolyte concentrations, 2) serum and urine osmolalities, 3) arterial blood gases, 4) total and fractional serum proteins, 5) blood urea nitrogen, complete blood count and blood sugar concentration, 6) changes in body weight, 7) sodium, potassium and water balance. The water load received by the HLS group was significantly less through 48 hours postburn (49% at 8 hours, 44% at 24 hours and 38% at 48 hours postburn). Although the HLS group received significantly more sodium than the LRS group, there was no difference in sodium balance at 48 hours postburn. This is explained by the fact that the HLS group, at 48 hours postburn, retained significantly less of the administered sodium load (69% vs. 83%). Positive water balance was significantly greater in the LR group for the first 48 hours postburn. This study suggests that current hypotonic fluid regimens for burn resuscitation contain water in excess of that required for proper resuscitation. Severely burned children may be safely and efficiently resuscitated with conventional salt loads and one-third less than usual water loads.

Blood↗
PubMed1977

Surgical injury of the common bile duct.

Review of our experience with twenty-two bile duct injuries and the literature leads us to the following conclusions: (1) Most biliary strictures follow surgery and can be avoided by adequate exposure, accurate dissection, use of hemostatic clips rather than clamps and ties, and the liberal use of operative cholangiography. (2) Injuries diagnosed at the time of surgery should be repaired by end-to-end anastomosis over a T tube if length is adequate or by Roux-en-Y choledochojejunostomy if length is inadequate. (3) The diagnosis of biliary injury should be suspected when jaundice, biliary fistula, or cholangitis occur in the postoperative period. (4) IVC, PTC, ERCP, or fistulography should be used when possible to delineate the site of injury or stricture and assist in planning the operative repair. (5) Surgery should be performed as soon as the diagnosis is made and the patient is in satisfactory condition for operation. (6) Early reoperation may be necessary to establish drainage and prepare for a later definitive procedure. In some cases, definitive repair can be performed this time. (7) Most late strictures should be repaired with a choledochojejunostomy to a defunctionalized limb of jejunum when resection and primary end-to-end repair cannot be accomplished.

Adult↗
PubMed1976

Energy metabolism following thermal burns.

Partitional calorimetry was performed on burned rats with and without excision of the adrenal medullae; animals were housed at ambient temperatures of 20 and 28 C. Rates of excretion of urinary nitrogen were determined for the 12 hours before calorimetry runs. Covering the burn wound with polyethylene returned the evaporative heat loss to normal and resulted in a corresponding decrease in the rate of heat production. Excision of the adrenal medullae resulted in chronic hypothermia of burned rats housed at 20 C. The highest rate of excretion of urinary nitrogen occurred in burned rats with intact adrenal medullae housed at 20 C; this excretion rate was significantly reduced when similar animals were housed at 28 C. The net effect of preventing evaporative heat loss from the wounds of burned rats is the same as that of reducing dry heat loss by elevation of the ambient temperature. Both result in a reduction in the rate of heat production.

Adrenal Medulla↗
PubMed1976

Congenital dilatation of the bile ducts.

Our experience with five cases of cystic dilatation of the extrahepatic bile ducts is reported and compared with the literature. The following conclusions have been reached: (1) The etiology of this anomaly is primarily congenital but may involve an acquired component. (2) Diagnosis should be suspected when any of the triad of abdominal pain, right upper quadrant mass, or jaundice is present. (3) The diagnosis can usually be made in infants based on the clinical picture and routine radiologic studies. (4) Retrograde cholangiopancreatography is a useful tool in making the diagnosis in older children and adults. (5) Roux-en-Y choledochocystojejunostomy is the procedure of choice for type I cysts, excision for type II, and choledochocystoduodenostomy for type III.

Bile Ducts↗
PubMedDate not supplied

Alteration in temperature regulation induced by burn injury in the rat.

The preoptic anterior hypothalamus (POAH) of rats housed at three ambient temperatures was implanted with perfusion apparatuses. Response of heat production to displacement of POAH temperature was determined for control animals and animals with burns (31% +/- 3% total body surface area). At an ambient temperature of 22 degrees C there was a significant increase in thermosensitivity of the POAH for both control rats and rats with burns compared with thermosensitivity at 32 degrees C. Within ambient temperatures there was no effect on thermosensitivity detected for rats with burns compared with control rats. The threshold temperature for heat production was shifted significantly upward (p less than 0.05) both by a lower ambient temperature and by burn injury. The reference temperature for heat production was also shifted to the right by burn injury (p less than 0.05). The significant shifts to the right for threshold temperature and reference temperature for heat production enhance the organisms's ability to meet the stress of the hypermetabolic response. At a warm ambient temperature (32 degrees C) there are no significant differences in thermoregulation detected in animals with burns or control animals.

Animals↗
PubMedDate not supplied

The effect of ablation of the preoptic anterior hypothalamus on energy metabolism and plasma catecholamines after burn injury in the rat.

Rats with burn injuries demonstrate changes in thermoregulation including an upward shift of the set-point and reference temperatures with no change in sensitivity of the response in heat production to displacement of the temperature of the preoptic anterior hypothalamus. In the present studies, the response in plasma and urinary catecholamines to burn injury after destruction of the preoptic anterior hypothalamus was examined in the rat. Preoptic anterior hypothalamic lesioning impaired the hypermetabolic response to burn injury, and at 22 degrees C, burned lesioned rats were hypothermic. Furthermore, plasma levels and urinary excretion rates for catecholamines were not decreased in burned lesioned rats, but rather showed an inverse relationship with heat production. Burned lesioned rats were capable of maintaining body temperature at an ambient temperature of 28 degrees C. This suggests that a less precise thermoregulation is present in lesioned animals. Rats in which the preoptic anterior hypothalamus has been destroyed have reduced tolerance to burn injury.

Animals↗