The myelopoietic effects of a Serratia marcescens-derived biologic response modifier in a mouse model of thermal injury.

The proliferative defects observed in phagocytic stem cells after major thermal injuries may be caused by an inadequate production of colony-stimulating factors (CSFs), a family of hemopoietic cytokines necessary for the production and function of granulocytes and monocytes. In this study a biologic response modifier (S-BRM) consisting of sized vesicles derived from the cell membrane and ribosomes of Serratia marcescens was investigated in a mouse model of thermal injury to determine its ability to augment postburn myelopoiesis. Treatment of burned mice with S-BRM was well tolerated and was associated with statistically significant increases in absolute numbers of circulating granulocytes and monocytes compared with burned mice receiving saline solution. In addition, the size of the splenic myeloid stem cell compartment, as measured by granulocyte-macrophage stem cell colony formation in soft agar, was markedly expanded. Finally, plasma levels of CSF were increased significantly in burned mice receiving S-BRM but were not elevated in burned littermates treated with saline solution. These data suggest that production of CSF is suboptimal after thermal injury and S-BRM is capable of up-regulating postburn myelopoiesis by causing the release of CSF into the systemic circulation.

A prospective study of incisional time, blood loss, pain, and healing with carbon dioxide laser, scalpel, and electrosurgery.

Carbon dioxide laser incisions are reported to be less painful, less bloody, and less prone to seroma formation and to heal better than scalpel or electrosurgical incisions. We compared all three modalities in a prospective randomized study of cholecystectomy incisions. Time required for the incision and incisional blood loss was less with electrosurgery than with the carbon dioxide laser or scalpel. Postoperative pain and wound healing, however, were the same for all three techniques. The carbon dioxide laser appears to offer no advantage over conventional means of making a standard incision.

Cancers arising from burn scars. A literature review and report of twenty-one cases.

A review of the literature and a combined burn center study of the University of Beijing and the University of Colorado Health Sciences Center looking at cancer arising from old burn injuries are reported. This study indicates that of the 21 patients 76% were male, with an age range from 15 to 67 years. The lag period for all cancers ranged from 8 months to 60 years. The distribution of the cancer was greatest in the extremities, with 71%, followed by the scalp, with 14%. Forty-three percent of the patients were treated by excision and skin grafting. Twenty-nine percent were treated by amputation, 24% had radiation therapy, and 5% received no treatment. Of the 76% who were followed up to 8 years, no deaths were reported.

The development and evaluation of a clinical test of surgical resident proficiency.

The two purposes of this study were to develop a clinical test of surgical resident proficiency and to compare this clinical test with currently applied methods of resident evaluation. Appendicitis is a common surgical disease, and its accurate diagnosis depends largely on clinical acumen. Ten third-year surgical residents prospectively evaluated 107 patients admitted because of suspected appendicitis. After taking a history, performing a physical examination, and reviewing laboratory data, these residents were asked to state, as a percentage, the likelihood that each patient had appendicitis. Sixty-three patients had appendicitis documented by pathologic inspection after appendectomy. Forty-four patients did not have appendicitis, as was determined by operation (17) or by in-house observation and resolution of abdominal pain (27). These outcomes were used to calculate a diagnostic ability score (DAS) for each resident. Residents were evaluated by standard methods including in-service examinations and monthly evaluations by the attending staff. Residents were also evaluated by nonstandard, but potentially useful, neuropsychologic and psychologic tests, including the trail making test, the Ravens progressive matrices test, the paced auditory serial addition test (PASAT), the grooved pegboard test of manual dexterity, and the profile of mood states (POMS) psychologic questionnaire. Cumulative scores were calculated and compared by multiple regression with coefficient variance analysis. The correlation (R2) of DAS with standard evaluation techniques was as follows: In-service (0.055), faculty (0.508), trails (-0.293), Ravens (0.028), PASAT (0.251), dexterity (0.432), POMS (0.381). We found that (1) the DAS is a discriminating clinical test; (2) the DAS correlates with subjective faculty evaluation; and (3) the DAS does not correlate with in-service examination scores. We conclude that faculty evaluation remains the best currently applied test of surgical resident clinical proficiency as measured by the DAS.

Inhibition of colony-stimulating factor (CSF) production by postburn serum: negative feedback inhibition mediated by lactoferrin.

Fatal infections in severely burned patients are often preceded by a decline in the production of colony-stimulating factor (CSF) and the proliferation of granulocyte-macrophage stem cells (CFU-GM), and overwhelming sepsis is often associated with leukopenia. The underlying mechanisms accounting for these granulopoietic defects are poorly understood, but the fact that postburn serum has been shown to inhibit CSF production suggests that a humoral factor or factors may play a role. Previous work has demonstrated that plasma levels of lactoferrin (LF), a known inhibitor of CSF production, are elevated following burn injury. To determine if LF is responsible for serum-mediated inhibition of CSF production, serial plasma levels of LF were measured in 18 burn patients using an enzyme-linked immunoabsorbent assay (ELISA). LF was elevated within 24 hours of injury and was associated with an absolute granulocytosis which rapidly declined, reaching a nadir at postburn days 3 through 5. Postburn serum, especially when collected during the first 24 hours following burn injury, inhibited in vitro CSF production by normal human peripheral blood mononuclear cells. Pre-incubation of postburn serum with an LF antibody restored normal CSF production. These data suggest that LF may play an important role in the regulation of postburn granulopoiesis.

Burns in pregnancy.

A study conducted by the University of Colorado Health Sciences Center Burn Center of 42 burned pregnant patients indicates that the mortality of both the fetus and mother is dependent upon the percent body burn of the mother. Aggressive surgical therapy, including debridement with eschar excision and skin grafting, increases maternal survival. Chances of successful pregnancy were greatest when the mother was in her first or third trimester at the time of injury; however, no differences were noted in maternal or fetal mortality at different gestational months.

The effects of acute sleep deprivation during residency training.

Verbal and symbol concentration, learning, problem solving, clear thinking, manual skills, and memory were tested in 42 surgical residents to assess the effects of acute sleep deprivation on specific neuropsychological parameters. A series of eight neuropsychological tests--digit symbols, digit vigilance, story memory, trail making, PASAT, Raven matrices, delayed story, and pegboard--and a questionnaire on mood states were completed by the residents both when fatigued (less than 4 hours of sleep: mean, 2.0 +/- 1.5 hours) and when rested (more than 4 hours of sleep: mean, 6.5 +/- 1.0 hours), with at least 7 days between tests. In order to eliminate the effects of learning from the first test series, randomization of residents was performed so that one half were first evaluated when rested and one half when fatigued. ANOVA, multiple regression analysis, and the Student t test were used to assess differences. In the acute sleep-deprived state, residents were less vigorous and more fatigued, depressed, tense, confused, and angry (p less than 0.05) than they were in rested state. Despite these changes in mood, however, the responses on all of the functional tests were no different statistically in those who were rested and those who were fatigued (even in those with less than 2 hours' sleep). We conclude that acute sleep deprivation of less than 4 hours alters mood state but does not change performance in test situations in which concentration, clear thinking, and problem solving are important.

Identification of novel prognostic indicators in burned patients.

The size and depth of burn and patient age are useful early prognostic indicators in burned patients, but have limited value in predicting which patients in a given cohort are likely to die. The objective of this study was to identify additional variables in the first 10 days of burn injury which could better predict patient outcome. Variables consisting of demographic information, routine laboratory data, and clinical observations on 89 burned patients (63 survivors and 26 nonsurvivors) were analyzed. Compared to survivors, nonsurvivors had significantly larger burns (58 +/- 23% vs. 37 +/- 17%; p less than 0.0002) and a higher incidence of Gram-negative septicemia (20 of 26 [77%] vs. 24 of 63 [38%]; p less than 0.001). Potential prognostic variables were subjected to multivariate logistic regression analysis for each of the first 10 days following burn injury in order to identify a combination of parameters which predicted patient outcome. The regression analyses revealed that, as previously demonstrated, patient age and burn size were significant predictors of mortality on admission and throughout the first 10 days postburn. In addition, absolute monocyte count (AMC), absolute lymphocyte count (ALC), maximum daily temperature (Tmax), and BUN were also significant predictors (p less than 0.05). These data indicate that logistic regression models can identify simple prognostic variables in burned patients which may improve clinicians' ability to identify high-risk patients early in the course of their burn injuries.

Infrarenal venous anomalies and aortic surgery: avoiding vascular injury.

Anomalies of the left renal vein (retroaortic left renal vein and left renal vein collar) and the inferior vena cava (left-sided inferior vena cava and caval duplication) occur relatively infrequently but pose potential hazards to the surgeon during aortic repair. We report the cases of three patients in which one or a combination of these anomalies of the renal vein and inferior vena cava was present. The embryologic origins of each of the anomalies are discussed, and suggestions, both surgical and nonsurgical, are proposed that might aid the surgeon in avoiding injury and subsequent bleeding from these anomalous structures during surgical operations on the abdominal aorta.

Carbicarb: an effective substitute for NaHCO3 for the treatment of acidosis.

Carbicarb (Na2CO3 0.33 molar NaHCO3 0.33 molar), a mixture formulated to avoid the objections to sodium bicarbonate therapy, has been compared with 1 mol/L NaHCO3 and 1 mol/L NaCl in the treatment of mixed respiratory and metabolic acidosis (pH 7.17) produced by asphyxia in rats. In clinically appropriate doses, intravenous NaHCO3 raised arterial pH only 0.03 unit, elevated arterial carbon dioxide pressure, and doubled lactate concentration. With Carbicarb, the pH rise was three times as great and the blood lactate level was unchanged. The new drug should be effective in treating the acidosis of cardiopulmonary failure without raising blood carbon dioxide pressure or lactate levels and at lower sodium doses than required for NaHCO3.

Early vascular grafting to prevent upper extremity necrosis after electric burns: additional commentary on indications for surgery.

Early vascular grafting has been used to reestablish circulation to the hand in the treatment of electric injuries of the wrist with arterial damage. Since 1972 this therapy has yielded good results by preventing necrosis of the injured hand and by helping to maintain function. However, the indications and timing for performing this operation still are poorly defined. The surgeon is faced with the difficult task of determining whether the injury is severe enough to affect distal circulation and thereby lead to necrosis. The lack of reliable clinical signs is chiefly responsible for this difficulty; however, the potential for delayed thrombosis of vessels complicates the problem. In this article, indications for early vascular grafting in an electrically injured wrist are discussed based on recent clinical experience, with emphasis on the use of arteriography. A case history involving electric burns of both upper extremities is presented as an illustration.

Creatinine phosphokinase values in electrical and thermal burns.

Twenty-six patients were evaluated with regard to CPK values in week 1 post-burn. Patients were allocated into two groups based on the severity of burn injury. Group 1 included patients with minor electrical or thermal injury, and Group 2 those patients with deep thermal injury and objective evidence of muscle necrosis. With the exception of day 5 post-burn, Group 2 had significantly increased CPK levels as compared to Group 1. This indicates that CPK levels, especially with electrical and deep thermal burns, are sensitive tests in evaluating the depth of burn injury such that an appropriate pre-operative strategy for debriding and grafting is possible.

Early vascular grafting to prevent upper extremity necrosis after electrical burns: anastomotic false aneurysm, a severe complication.

From May 1972 to January 1982, early vascular grafting was used to re-establish circulation across the electrically burned wrist. Thirty-three thrombosed arterial segments (radial and/or ulnar arteries) were removed in 18 limbs and autografts of the greater saphenous or omental veins were used for the revascularization. One vascular graft, which had been sutured to the ulnar artery on day 3 post-injury, contained an anastomotic false aneurysm at the proximal anastomosis. One month after vascular grafting, this aneurysm ruptured and bled. An emergency exploration of the wrist confirmed the diagnosis and surgery successfully restored the circulation, avoiding amputation of the injured limb. Histopathological examination of the specimen was consistent with the presence of anastomotic false aneurysm. The pathogenesis of this complication is reviewed. Our experience indicates that circulation to a limb following electrical injury can be successfully restored by early vascular grafting, but emphasizes the importance of close periodical follow-up after graft acceptance due to the possibility of late anastomotic complications.

Flexible angioscopy seems faster and more specific than arteriography.

Fiberoptic angioscopy was performed with 2.5- and 3.3-mm angioscopes in 25 arteries and grafts in 19 patients. Radiologically normal and abnormal arteries and anastomotic sites were examined. All vessels and grafts were visualized and images of normal arterial wall, subclinical and obstructing atherosclerotic plaque, and suture lines were defined. Unexpected endovascular findings were noted in five patients (26%) and included large amounts of free-floating clot (one patient), atherosclerotic debris (two patients), and membranelike obstructions (two patients). Angioscopy required three to ten minutes and resulted in no complications. Experience with the flexible angioscope indicates that satisfactory visualization and specific recognition of angiographically unsuspected problems can be obtained. The flexible angioscope is faster and appears more etiologically specific than arteriography.

The use of infrared photoplethysmography in identifying early intestinal ischemia.

Acute intestinal ischemia and infarction remain serious clinical problems despite early operative intervention. An accurate and reproducible method of assessing ischemic tissue is critical to determine the precise limits of resection. The purpose of this study was to compare the utility of infrared photoplethysmography, intravenous fluorescein, and Doppler ultrasound in assessing intestinal ischemia in an operative canine model. After five segmental mesenteric arterial ligations in each of six conditioned dogs, the detection threshold for the limits of arterial perfusion of each modality was determined and correlated with the respective histopathologic specimens. Infrared photoplethysmography proved to be 100% sensitive for ischemia when its waveform amplitudes were 50% or greater of matched reference waveforms, whereas both intravenous fluorescein and Doppler ultrasound were 88% sensitive. All were comparably specific. We conclude that infrared photoplethysmography is comparable to intravenous fluorescein and Doppler ultrasound in the assessment of ischemic intestinal segments.