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Biomedical subjects

B A Pruitt

Publications and source records attributed to B A Pruitt.

At least 163 records · Page 9Linked to original sources
PubMed1984

Characteristics and uses of biologic dressings and skin substitutes.

Biologic dressings used for temporary coverage of open wounds exert both mechanical and physiologic effects by protecting the wound, maintaining microbial control, and hastening wound maturation. Synthetic wound dressings modeled after the biologic dressings have been evaluated by several investigators. Those studies have shown unilaminate synthetic membranes to be ineffective when applied to full-thickness wounds and have identified a bilaminate construction as being necessary for membranes to serve as effective skin substitutes. The desirable properties of skin substitutes have been identified and incorporated in the design of recently developed membranes. Recent studies in this and other laboratories have resulted in the development of collagen-synthetic bilaminates, a totally synthetic biologically inert bilaminate, and tissue culture-derived membranes. The characteristics and limitations of each skin substitute determine the optimum usage of these composite membranes and define the modifications needed to improve the effectiveness of such dressings.

Animals↗
PubMed1984

Altered protein metabolism in diaphragms from thermally injured rats.

Thermal injury is known to cause increased muscle catabolism, but the mechanisms involved in this process are not clear. Diaphragms from thermally injured rats were removed and incubated in vitro on the third postburn day in order to determine the rates of protein synthesis and degradation using [14C]tyrosine uptake and release as an indicator of these processes. Diaphragms from rats that received 50% total body surface, full-thickness wounds and unburned sham-treated controls were examined. The rate of protein synthesis in the absence of insulin supplementation was found to decrease (26%) and the rate of protein degradation increased (81%) under these conditions. Insulin supplementation (0.1 U/ml) to the incubation media caused a significant increase (39%) in the rate of synthesis in the sham-controls but did not stimulate synthesis in the burned group. Degradation rates measured in the presence of insulin were increased in the burned group (64%), but were somewhat blunted in comparison to the insulin-deficient degradation rates (81%). These results indicate that diaphragm muscles from thermally injured rats show a decreased insulin stimulation of protein synthesis after injury, and insulin does not significantly alter the enhanced rate of protein degradation observed in these muscles after injury.

Animals↗
PubMed1983

Subeschar treatment of burn-wound infection.

Within a 24-month period, 454 patients were admitted with burns (average size, 33% of the total body surface [TBS]). Wound infection developed in 19, who subsequently were treated with subeschar antibiotics. The average burn size in those 19 patients was 63% of the TBS, with an average full-thickness injury of 47%. Five (26%) of the 19 survived, and five others died without evidence of wound infection, giving a would clearance rate of 52.6%. The five surviving patients (average burn size, 59% TBS) underwent excision of infected tissue, with split-thickness cutaneous autograft closure of the burn wound, after the course of subeschar antibiotic infusion. All surviving patients were infected with Pseudomonas aeruginosa. Subeschar infusion of semisynthetic penicillins, therefore, is an effective adjunct in the care of the patient with Pseudomonas burn-wound infection.

Administration, Topical↗
PubMed1983

Neutral proteinase activity in skeletal muscle from thermally injured rats.

Male Sprague-Dawley rats that received 60% total body surface, full-thickness, scald burns on the dorsum and abdomen were used in this study. Neutral proteinase and Ca2+-activated neutral proteinase activities were measured in gastrocnemius and soleus muscles at 3 and 21 days after the thermal injury. Neutral proteinase activity decreased significantly in the soleus (50%) and gastrocnemius (46%) muscles on the third postburn day. Ca2+-activated neutral proteinase was unchanged at this time. Neutral proteinase and Ca2+-activated neutral proteinase activities were unaltered at 21 days postinjury. These results may reflect a protein-sparing effect on the third postburn day which could be an early intracellular change prior to an increase in selected enzyme proteins during the hypermetabolic phase after thermal injury.

Animals↗
PubMed1983

Randomized trial of efficacy of crystalloid and colloid resuscitation on hemodynamic response and lung water following thermal injury.

To assess the effects of crystalloid and colloid resuscitation on hemodynamic response and on lung water following thermal injury, 79 patients were assigned randomly to receive lactated Ringer's solution or 2.5% albumin-lactated Ringer's solution. Crystalloid-treated patients required more fluid for successful resuscitation than did those receiving colloid solutions (3.81 vs. 2.98 ml/kg body weight/% body surface burn, p less than 0.01). In study phase 1 (29 patients), cardiac index and myocardial contractility (ejection fraction and mean rate of internal fiber shortening, Vcf) were determined by echocardiography during the first 48 hours postburn. Cardiac index was lower in the 12- to 24-hour postburn interval in the crystalloid group, but this difference between treatment groups had disappeared by 48 hours postburn. Ejection fractions were normal throughout the entire study, while Vcf was supranormal (p less than 0.01 vs. normals) and equal in the two resuscitation groups. In study phase 2 (50 patients), extravascular lung water and cardiac index were measured by a standard rebreathing technique at least daily for the first postburn week. Lung water remained unchanged in the crystalloid-treated patients (p greater than 0.10), but progressively increased in the colloid-treated patients over the seven day study (p less than 0.0001). The measured lung water in each treatment group was significantly different from one another (p less than 0.001). Cardiac index increased progressively and identically in both treatment groups over the study period (p less than 0.01). These data refute the existence of myocardial depression during postburn resuscitation and document hypercontractile left ventricular performance. The addition of colloid to crystalloid resuscitation fluids produces no long lasting benefit on total body blood flow, and promotes accumulation of lung water when edema fluid is being reabsorbed from the burn wound.

Adolescent↗
PubMed1983

Inappropriate vasopressin secretion (SIADH) in burned patients.

To determine if concentration of plasma arginine vasopressin (AVP) is inappropriate for the plasma Na+ concentration in hyponatremic burned patients, we obtained 32 plasma samples from 20 patients with total burn size (TBS) 15 to 80% of body surface on or after postburn day (PBD) 4 in the morning following all-night recumbency. In the 25 samples (17 patients) with hyponatremia, AVP was elevated, 1.6 to 14.3 (normal less than 0.5) pg/ml. Most patients with normal serum Na+ had normal AVP values. Out of the total, nine patients (12 samples) without renal failure or sepsis, selected also for hyponatremia and urinary Na+ greater than or equal to 20 mEq/L, were considered separately. BUN of 11.7 +/- 1.8 mg/dl and plasma glucose of 130 +/- 5.6 mg/dl, Na+ of 130 +/- 1.1 mEq/L, calculated osmolality of 272 +/- 1.6 mosm/kg, and cortisol of 20.4 +/- 1.6 micrograms/dl were associated with a 24-hour fluid intake of 4.3 +/- 0.26 L and urinary output of 2.7 +/- 0.33 L, Na+ of 80 +/- 14 mEq/L, and osmolality of 520 +/- 73 mosm/kg (mean +/- SE). In all of the plasma samples, AVP was markedly elevated (6.9 +/- 1.1 pg/ml). In another study, four hyponatremic burned patients were given a standard water load. Excretion of the water was delayed, and further dilution of the initially hypotonic plasma resulted in a fall of urinary osmolality and plasma AVP. Cutaneous thermal injury can cause resetting of the mechanism linking plasma tonicity and AVP secretion resulting in dilutional hyponatremia. This syndrome occurs in the absence of gross physiologic perturbations such as volume depletion or adrenal insufficiency.

Adolescent↗
PubMed1983

Prospective study of burn wound excision of the hands.

To examine the role of early excision and grafting in the preservation of maximal function of hands with deep dermal burns, we prospectively evaluated 164 burned hands in consecutively admitted patients (mean age, 29 years; mean burn size, 37% of body surface). All hands with burn depths of second degree, deep second degree, or third degree above the level of the tendons and joint capsules were assessed preoperatively, intraoperatively, and at discharge from the hospital. Patients were treated by excision and grafting in the first or second postburn week, by delayed grafting alone, or by allowing primary healing. Total active range of motion measurements were made on the day of discharge (mean, 64th postoperative day). Mean operative blood loss per hand was 1,270 ml. When all (alive and dead) patients undergoing early excision and grafting were examined by a binomial probability model, early surgery was shown to produce no adverse affect on survival. Excision and grafting of hands with deep dermal burns, whether early or late, offered no advantage over physical therapy and primary healing in maintaining hand function. Likewise, hands with more superficial burns responded equally to operative and nonoperative treatment. While early excision and grafting of hands with third-degree burns tended to produce poorer results than did initial nonoperative care and late grafting, the differences are just outside the range of significance. Early excision and grafting of selected third-degree injuries of the hands may be indicated in patients with small total body surface burns in order to shorten hospital stay. However, early surgical intervention in patients with massive burns should be directed toward area coverage, not toward hand excision.

Adolescent↗
PubMed1982

Humoral-phagocyte axis of immune defense in burn patients. Chemoluminigenic probing.

Both serum opsonic capacity and granulocyte oxygenation activity were measured in 35 burn patients during their course of therapy. The microbicidal action of granulocytes is effected via the metabolic generation of oxygenating agents; introduction of chemoluminigenic substrates, such as luminol or dimethyl biacridinium dinitrate, allows ultrasensitive measurement of phagocyte oxygenation activity. Serum opsonic capacity can also be assayed by measuring the rate of activation of phagocyte oxygenation activity. Alterations in granulocyte oxygenation activity were observed in individuals patients in temporal association with changes in clinical condition, and sepsis was associated with a marked decrease in activity. An initial depression in opsonic capacity was noted at the time of admission of patients with major burns, more than 40% total body surface. Thereafter, depression of opsonic capacity was temporally associated with sepsis in individual patients. Chemoluminigenic probing provides a rapid, sensitive, and objective method for assessing the status of the humoral-phagocyte axis, and as a clinical laboratory technique is particularly applicable for monitoring patient populations in which sepsis is prevalent.

Acridines↗
PubMed1982

Altered muscle metabolism in rats after thermal injury.

Burn injury is associated with an elevation in total body oxygen consumption, increased hepatic alanine uptake and conversion to glucose, and a negative nitrogen balance. The primary source of the alanine used for gluconeogenesis by the liver and of the nitrogen lost as urea is believed to be from skeletal muscle. Selected muscle regulatory enzymes and pyruvate and oleate oxidation rates were assayed for maximal activity during the postburn period. Male Sprague-Dawley rats that received 50% total body surface scald burns on the dorsum and abdomen were examined for citrate synthase (CS), phosphofructokinase (PFK), and glutamate-pyruvate transaminase (GPT) activity in uninjured muscle at 3, 7, 13, and 20 days postburn, and the ability of muscle to oxidize pyruvate and oleate was measured at 3 and 13 days after injury. Cs, PFK, and GPT activities increased significantly (p less than 0.05) by 13-20 days after injury in the soleus and diaphragm. The epitrochlearis showed no change in CS, but PFK and GPT were elevated within this time frame. The gastrocnemius muscle showed an elevated oleate oxidation rate at 13 days after injury, but no change at 3 days postburn. Pyruvate oxidation rates were unaltered. The results of this study indicate that during the postburn period several metabolic alterations occur in muscle. These adaptations include: (1) elevated CS activity which may be associated with increased oxidative capacity,, (2) increased PFK activity which implies that more substrate is being shuttled through the glycolytic pathway, (3) increased GPT activity which may reflect increased pyruvate conversion to alanine, and (4) increased oleate oxidation rates which demonstrate that muscle is utilizing more fatty acid substrates during the postburn period.

Adaptation, Physiological↗
PubMed1982

Depressed reflex vasomotor control of the burn wound.

Total leg blood flow was measured by venous occlusion plethysmography in five normals and 14 burned patients before and after 30 min of external heating. Leg surface temperatures were held constant, but rectal temperatures increased on the average of 0.4 to 0.5 degrees C in all subjects following this heat load. Leg blood flow increased by 56.0% in the controls, 63.2% in five patients with essentially no leg burn (mean burn size = 1.5% leg surface), and 9.6% in nine patients with major leg injuries (mean burn size 55% leg surface). Failure of reflex vasodilatation in the burned leg was evident up to 107 days postinjury even when the wound was well-healed. All subjects sweated freely from the unburned skin. In two patients, where arm and leg blood flows were measured simultaneously, flow to the uninjured arm increased while that to the injured leg remained unchanged. This lack of reflex vasodilatation in the burned limbs suggests either that wound vessels are denervated or that they are so dilated in the basal state that further dilatation is limited. The bulk of this and other data would support the denervation concept. This physical or chemical denervation could occur at the time of injury, be localised to the area of the wound, and result in loss of both neurogenic vasoconstrictor tone and active reflex vasodilatation.

Adult↗
PubMed1982

Hypermetabolic low triiodothyronine syndrome of burn injury.

The free tetraiodothyronine index (FT4I) and free triiodothyronine index (FT3I) in burn patients represented the serum levels of free (dialyzable) T4 and free T3, respectively. FT4I and FT3I were lower with greater burn size and were lower in nonsurvivors than expected for the burn size. there was no compensatory elevation of basal or releasing hormone-stimulated thyrotrophin (TSH) concentrations. Reverse T3 was higher with greater burn size. T3 treatment restored FT3I but did not affect mortality or resting metabolic rate (MR) measured in survivors, compared with placebo therapy. Whereas the hypermetabolic response to burn injury appeared t be independent of thyroid hormones, MR was correlated positively with burn size and with elevated plasma norepinephrine and epinephrine concentrations for several weeks after injury. Lack of augmented TSH concentrations, absence of low plasma reverse T3, and presence of hypermetabolism suggest that the reduced plasma free T3 does not indicate functional hypothyroidism, but may represent an adaptation to the assumption of metabolic control by the sympathetic nervous system.

Adolescent↗
PubMed1982

Management of abdominal wounds in thermally injured patients.

Over a 10-year period, 103 burned patients (mean age, 25 years; mean burn size, 43% of the total body surface) required an intra-abdominal operation. Life-threatening complications dictated operative intervention, and the complications resulted in increased mortality. Abdominal incisions dehisced in 33 patients. In 75 patients whose 91 incisions were closed with retention sutures, 18 wounds (20%) separated postoperatively, including seven in which synthetic sutures disrupted. In 28 patients whose 35 abdominal incisions were closed without retention sutures, 15 wounds (43%) dehisced. Placement of the abdominal incision through the burn wound appeared not to affect the incidence of dehiscence. When an abdominal operation is required in burned patients, their wounds should be closed by stainless steel wire, usually as retention sutures, placed through all muscle and facial layers of the abdominal wall.

Abdominal Injuries↗