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Biomedical subjects

W F McManus

Publications and source records attributed to W F McManus.

At least 55 records · Page 3Linked to original sources

Upper airway sequelae in burn patients requiring endotracheal intubation or tracheostomy.

During a period of 11 1/2 months, 41 of 217 adult burn patients admitted to the U.S. Army Institute of Surgical Research Burn Center required endotracheal intubation or tracheostomy for management of the airway and/or ventilatory assistance. Permanent upper airway sequelae were recorded and related to presence of inhalation injury, duration of tube placement, cuff pressure, and pulmonary compliance. An "inhalation injury scoring system" based upon history, physical examination, bronchoscopic findings, and abnormalities at 133xenon lung scan correlated well with postinjury alteration in compliance and subsequent sequelae. Significant inhalation injury was found in 35 patients. Seventeen of the study patients survived (Group I) and 24 patients expired (Group II). Group I patients were screened for permanent airway sequelae by fiberoptic bronchoscopy, xeroradiograms, and spirometry undertaken an average of 11 weeks after extubation or decannulation. Four patients developed tracheal stenosis and five patients had significant tracheal scar granuloma formation. Sequelae were generally more frequent and more severe after tracheostomy than after translaryngeal intubation, and duration of tube placement and presence of a tracheal stoma were the most important etiological factors in permanent damage. For initial respiratory support, we favor the use of translaryngeal (nasotracheal) tubes for periods up to 3 weeks. Fiberoptic bronchoscopic examination is the most reliable follow-up method for detecting anatomic damage in such patients. Spirometry can be used as a noninvasive screening test and xeroradiograms are helpful in assessing the degree of tracheal stenosis.

Adolescent↗

Tetanus following a major thermal injury.

A case of tetanus in an unimmunized burned patient is presented. This foreign national sustained a 32% total body surface area burn, received inadequate prophylaxis initially, and subsequently developed tetanus 11 days postburn.

Aged↗

Frozen section technique to evaluate early burn wound biopsy: a comparison with the rapid section technique.

The importance of early diagnosis and treatment of burn wound infection has prompted many efforts to use frozen section technique for processing burn wound biopsies, most of which have been unsuccessful. A frozen section technique which facilitates quick, reliable evaluation of biopsies was developed, and has been used in the evaluation of 169 biopsies over a period of 18 months. The frozen section technique takes 30 minutes compared with 4 hours for the rapid section method. Comparison of diagnoses made using both methods for each of the 169 biopsies produced a 96% coincidence. Each discrepant diagnosis was corrected by the rapid technique approximately 3 1/2 hours after the frozen section diagnosis. The frozen section technique is a generally accurate and rapid means of assessing the microbial status of a burn wound and diagnosing invasive infection. Permanent sections produced by rapid section technique should always be examined to confirm the frozen section diagnosis.

Biopsy↗

Alterations of mental status and thyroid hormones after thermal injury.

In 16 burn patients, mean values for serum T4 and T3, their T3 uptake-derived free indices (FT4I and FT3I) and dialysis-derived free concentrations (FT4 and FT3) were depressed (all P less than 0.001) compared to respective means in 13 normal subjects. In the patients, the free hormone indices were relatively more depressed below control values than were the free hormone concentrations. However, within the group of burn patients, variation in FT4I reflected that of FT4 (r = 0.91), and variation in FT3I reflected that of FT3 (r = 0.93). We then studied serum T4, T3, and their free indices in 134 patients (burn size, 6-96% of the skin area), including 45 nonsurvivors, none of whom received steroid, dopamine, or iodine treatment. At each sampling, the level of obtundation (LO) was determined on a 6-point scale from normal to deep coma. Whereas initially low mean FT4I values rose in survivors, they remained lower in nonsurvivors than in survivors until death in the nonsurvivors. In nonsurvivors, mean LO worsened in the first week and remained worse than that in survivors until death. Multiple regression analyses showed that for a given age or burn size, nonsurvival was better correlated with lower T4 or FT4I than with T3 or FT3I, but was even more closely correlated with worse LO (P less than 0.001). Exclusion of data obtained within 24 h of narcotic or tranquilizer doses did not weaken the relationship of nonsurvival with LO and FT4I. Nonsurvival after burn injury was associated with reduced T4, FT4I, and mental status for up to weeks before death, this association being independent of treatment with drugs acting on mental status or thyroid function.

Burns↗

Thermal injury in the pregnant patient.

Thermal injury sustained during pregnancy presents special management problems for both the gravid woman and her unborn child. Of 6,573 admissions to this burn center during the period of 1950 through 1982, 1,157 (17.6 per cent) were female and 448 (6.8 per cent) were of reproductive age. Thirty of this latter group (6.7 per cent) of burned patients were pregnant at the time of injury. These 30 patients ranged in age from 16 to 37 years old (an average of 22.7 years) and the burned portion of the total body surface area ranged from 6 to 92 per cent (an average of 39.7 per cent). A review of the clinical courses of these 30 patients suggests several observations and conclusions. Pregnancy does not alter the maternal outcome after thermal injury and maternal survival is usually accompanied by fetal survival in the absence of significant complications. If the injury of the gravid patient is lethal, the pregnancy will usually terminate spontaneously prior to her death. Obstetric support and aggressive fetal monitoring is recommended for all moderately and severely burned pregnant patients. Obstetric intervention may be considered in the ill patient with a near term fetus in whom significant complications (such as, hypotension, hypoxemia or sepsis) jeopardize the life of the fetus.

Adolescent↗

Replacement therapy with modified immunoglobulin G in burn patients: preliminary kinetic studies.

Suppression of serum immunoglobulin G for periods ranging from days to weeks following thermal injury may enhance the risk of infection in burn patients. In an initial trial, we attempted to determine whether intravenous pulses of Immunoglobulin G (IgG) will establish and maintain normal serum IgG concentrations in this interval. The levels of endogeneous serum IgG in eight control patients, mean total burn size 45 percent body surface area (no IgG infusions), were measured by radial immunodiffusion on various postburn days. Commercially available reduced alkylated IgG (5 percent Gamimune, Cutter Biological, Berkeley, California) was infused in doses of 500 mg/kg twice per week in four patients (total burn size 32 percent) and once per week in five patients (total burn size 47 percent), beginning during the first postburn week. Circulating IgG was measured prior to each infusion and at three postinfusion times: (1) 15 minutes (peak), (2) one day, and (3) either day 3, 4, or 6. Surgery or blood transfusions prior to one of these time points invalidated kinetic analysis of some infusions. Exponential two-point decay constants for total serum IgG after each of 24 infusions were calculated separately for early (day 0-1) and later (day 1-3 or 1-4) postinfusion intervals and assessed by stepwise regression analysis to determine sources of variation in decay. Early decay was seen to be faster with larger burn size after accounting for variation of decay with preinfusion and peak IgG values. Later decay was not related to burn size. Maltose, a constituent of the IgG preparation, was detectable in serum for only four to eight hours after each infusion and may have contributed to a 20 percent increase in total serum glucose between four and eight hours postinfusion. Mean serum IgG in patients given infusions twice weekly was in the normal range after one infusion, about a week earlier than in untreated patients. Such infusions maintained normal IgG levels.

Agammaglobulinemia↗

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↗

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↗

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↗

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↗

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↗

Burn wound infection.

Ninety-seven of 763 patients admitted to a burn center during a 3-year period had histologically confirmed bacterial or fungal burn wound invasion. Nine of these 97 patients survived and 88 died. Burn wound infection was the principal cause of death in 57 patients and was diagnosed perimortem in an additional 31 patients but was not judged to be the primary cause of death. Pseudomonas aeruginosa continues as the most frequent offending organism. The variety of mycotic and bacterial organisms identified, however, suggests that the compromise of the host is the critical factor, and not any particular microorganism. A variety of combinations of treatments are described: the selection of treatment depends upon the type and extent of infection.

Adolescent↗

Experimental inhalation injury in the goat.

Inhalation injuries are usually produced by inhalation of gaseous or particulate products of incomplete combustion and are rarely due to heat per se unless steam is inhaled. The clinical and anatomic characteristics of an appropriate animal model should mimic the disease encountered clinically. A model of inhalation injury has been produced in anesthetized goats through the use of a modified bee smoker. The smoke is delivered at a low temperature and contains byproducts of incomplete combustion. This reproducible injury produces necrotic tracheobronchitis and bronchiolitis with pseudomembrane and cast formation in association with mild multifocal atelectasis and bronchopneumonia. These lesions spontaneously resolve within 3 weeks without supportive therapy. The upper trachea, protected from smoke injury by the inflated cuff of the endotracheal tube, showed no evidence of injury. This nonlethal injury is proposed as an appropriate model for evaluation of the pathophysiology and treatment of inhalation injury.

Animals↗

Diagnosis and treatment of cannula-related intravenous sepsis in burn patients.

Suppurative thrombophlebitis was identified in 193 (4.2%) of 4,636 burn patients treated during the years 1960-1978. A single vein was involved in 162 patients, while 31 had multiple vein involvement. The distribution and incidence of suppuration in individual veins reflected the frequency of cannulation, with an increase in the use of central vein cannulae, during the last 10 years, paralleled by a rise in central vein suppuration. The infecting organisms reflected the patients' surface flora. Local signs of infection were present in less than half (35%) of the patients and recovery of a positive blood culture in a clinically septic patient was the most frequent clinical presentation prompting exploration of previously cannulated veins. Pathogenetic mechanisms are identified and criteria defined for determining the extent of excision necessary. Ninety veins were excised from 75 patients during the 1969-1978 period, of whom 30 (40%) survived (three other patients with antibiotic treated central vein disease also survived). Treatment failure was attributable to inadequate excision in 12 patients, suppuration within another unexcised vein in eight patients, hematogenous dissemination of infection in five patients in whom the local disease had been eradicated, and other disease in 20 patients. Prophylaxis must emphasize limited duration of cannulation. Timely diagnosis and treatment can effect maximum salvage and reduce the likelihood of systemic dissemination.

Adolescent↗

Subeschar antibiotic infusion in the treatment of burn wound infection.

In a reproducible infected rat burn model, subeschar infusion of antibiotics failed to protect the animals from death via burn wound invasion excepting those animals receiving carbenicillin. Subcutaneous injection of maximal doses of carbenicillin at a distance from the burn wound protected these animals equally well. Some advantage was defined for the subeschar route of administration with suboptimal doses of carbenicillin. More important is the fact that propective selection of an effective antibiotic could not be made on the basis of in vitro antibiotic sensitivity tests.

Animals↗

Prehospital advanced emergency care: a potential pitfall.

Effective prehospital treatment of the severely injured and acutely ill by an Advanced Emergency Care system may change symptoms and signs by the time patients arrive at the hospital. To provide optimal care, physicians must appreciate the capabilities and limitations of the EMT-paramedic. The EMT-paramedic must report verbally and via written record the course of prehospital events. Cardiac rhythms must be documented for review. It should be the responsibility of the medical directors of such Advanced Emergency Care systems to provide supervision, refresher training, critiques, and evaluation, to establish medical responsibility and credibility.

Adult↗