Noncompliance of health care workers with universal precautions during trauma resuscitations.

BACKGROUND: Universal precautions during resuscitations are mandated by hospital regulations. We documented adherence to universal precautions during trauma resuscitations at our level I trauma center. METHODS: During trauma resuscitations, a medical student using an elevated viewing platform observed health care workers (HCWs) for the use of barrier precautions (BPs): gloves, masks, gowns, and eyewear. Only HCWs having direct patient contact were included. The purpose of the observation was not disclosed to those being observed. RESULTS: In 12 resuscitations involving 104 HCWs, none had 100% compliance with BPs. Compliance rates for individual BPs were gloves, 98%; eyewear (any type), 52%; gowns, 38%; masks, 10%; and eyewear (with side protectors), 9%. Resuscitations in which bleeding was observed involved 59 HCWs with 38% compliance; only 2 used full BPs. No difference in compliance rates occurred during the study period. CONCLUSIONS: Experienced trauma care HCWs are cavalier regarding blood-borne disease exposure risks. Measures to encourage (or force) compliance are needed.

Higher risk of HIV transmission during trauma resuscitations.

Despite an appreciation of the potential for blood borne pathogen exposure, compliance of universal precautions is low. While reports of HIV positive rates in trauma patients have varied from 0.15% to 7.8%, the estimated prevalence of HIV in Louisiana is 0.32%. We made use of two unique, complimentary data sources: the Trauma Registry and the HIV/AIDS Reporting System database of known HIV positive patients to estimate the relative prevalence of HIV which may indicate an increase risk of blood borne pathogen transmission to health care workers during trauma resuscitations. In one year, 1031/1159 patients were evaluated from the Trauma Registry Database and 22 similar patients (2.13%) were found in both the Trauma Registry and the HIV/AIDS Reporting System Database. Our prevalence is an indicator of the minimum risk since it is based on only reported cases of HIV and justifies intensification of education and enforcement of the practice of universal precautions.

Evolution in the management of hepatic trauma: a 25-year perspective.

OBJECTIVE: To define the changes in demographics of liver injury during the past 25 years and to document the impact of treatment changes on death rates. SUMMARY BACKGROUND DATA: No study has presented a long-term review of a large series of hepatic injuries, documenting the effect of treatment changes on outcome. A 25-year review from a concurrently collected database of liver injuries documented changes in treatment and outcome. METHODS: A database of hepatic injuries from 1975 to 1999 was studied for changes in demographics, treatment patterns, and outcome. Factors potentially responsible for outcome differences were examined. RESULTS: A total of 1,842 liver injuries were treated. Blunt injuries have dramatically increased; the proportion of major injuries is approximately 16% annually. Nonsurgical therapy is now used in more than 80% of blunt injuries. The death rates from both blunt and penetrating trauma have improved significantly through each successive decade of the study. The improved death rates are due to decreased death from hemorrhage. Factors responsible include fewer major venous injuries requiring surgery, improved outcome with vein injuries, better results with packing, and effective arterial hemorrhage control with arteriographic embolization. CONCLUSIONS: The treatment and outcome of liver injuries have changed dramatically in 25 years. Multiple modes of therapy are available for hemorrhage control, which has improved outcome.

A critical assessment of endpoints of shock resuscitation.

Modern hemodynamic therapy is not only the recognition and treatment of hypotension but also the avoidance and treatment of shock in its broadest sense. The major issues include the recognition of hypoperfusion of the body as a whole or its individual tissues and organ systems and the determination of the best endpoints for the treatment of shock. Even if all of the commonly used clinical indicators of shock are "normal," shock on a cellular, tissue, or organ basis may still be present. Whether "organ-specific" assessments, such as gastric tonometry or tissue oxygen tension measurement, are the ultimate answer to this problem remains to be seen. The determination of adequate intravascular volume (preload) continues to present major difficulties in the care of critically ill or injured patients. Although PCWP is frequently helpful, it is not a gold standard. A bedside ultrasonic technique, such as esophageal Doppler sonography, may replace the Swan-Ganz catheter technique in many patients.

Post-treatment dopexamine infusions partially reverse reductions in cranial mesenteric blood flow and mucosal oxygenation induced by hypoxia in newborn piglets.

A severe hypoxic insult is known to induce dramatic reductions in newborn intestinal blood flow and is, thus, considered a vector for the development of neonatal intestinal ischemic diseases. Dopexamine (DPX) is a novel synthetic agent that has potent B2-adrenoceptor and dopaminergic activity, the clinical effects of which include an increase in cardiac output and in mesenteric blood flow. Having previously shown that infusion of DPX before hypoxia (HYP) mitigated the reduction in newborn mesenteric blood flow, we sought to define its efficacy when given after an established hypoxic insult. Ultrasonic transit time blood flow probes were placed around the ascending aorta and cranial mesenteric artery of anesthetized, mechanically ventilated 0 to 2-day-old piglets. Small bowel mucosal oxygenation was observed with a tissue oxygen monitoring system. After stabilization, animals were subjected to one of the following: HYP (FIO2 = 0.12) for 60 minutes (n = 12); DPX (5 microg/kg/min) infusion begun 10 minutes after induction of HYP/DPX (n = 11). Almost no alterations in any of the monitored variables were shown in a group (n = 5) of similarly instrumented, untreated animals. In contrast, although both hypoxic piglet groups experienced significant (P < 0.05, analysis of variance) declines from baseline cardiac output, mesenteric blood flow, and mucosal oxygenation, each of these deleterious effects was significantly (P < 0.05) blunted in the DPX-treated animals. During periods of systemic hypoxemia, the reductions in neonatal mesenteric blood flow and oxygenation can be somewhat blunted by DPX. As such, this agent may prove of clinical benefit when an infant is threatened by a hypoxic episode.

Laparoscopic retroperitoneal repair of recurrent postoperative lumbar hernia.

A patient who previously underwent an attempt at open mesh repair of a lumbar hernia that occurred following iliac crest bone harvesting was managed successfully by laparoscopic retroperitoneal fixation of the prosthetic material to the iliac crest using bone screws. A review of the literature supports the use of such a novel approach to manage this often vexing problem.

Esophageal Doppler ultrasound monitor versus pulmonary artery catheter in the hemodynamic management of critically ill surgical patients.

BACKGROUND: The pulmonary artery (PA) catheter has been used to determine hemodynamic indices; however, it has recently been criticized. This study was undertaken to evaluate an esophageal Doppler monitor (EDM) as a possible replacement for PA catheter in critically ill, mechanically ventilated patients. METHODS: EDM and PA catheters were placed in patients in the surgical intensive care units (n = 14, 118 matched sets of data). PA catheter and EDM measurements, including corrected flow time (FTc,) a measure of preload, were obtained. Pearson correlation (r) was analyzed to compare PA catheter and EDM measurements, and a nonlinear regression model was used to describe Starling Relationships. RESULTS: Cardiac output correlated between EDM and PA catheter (r = 0.6; p < 0.001). FTc correlated more strongly with cardiac output than did pulmonary capillary wedge pressure. (FTc: r2 = 0.27; p < 0.001; cardiac output: r2 = 0.04; p = 0.06). CONCLUSION: Corrected flow time is a better indicator of preload than pulmonary capillary wedge pressures. EDM seems to be at least as useful as PA catheter in managing the hemodynamic status of critically ill surgical patients.

Initial experience with laparoscopic repair of incisional hernias.

BACKGROUND: Development of a safe, unobtrusive means to repair the large incisional hernia continues to represent a challenge to surgeons. METHODS: A retrospective analysis of the first 12 patients who underwent an attempt at laparoscopic repair of an incisional hernia at a single institution was carried out. RESULTS: Of the 12 attempts at laparoscopic repair, 11 were completed. No serious perioperative morbidity was encountered. During a mean follow-up of 12.5 months, one recurrence (due to a technical shortcoming that has since been overcome) was identified. CONCLUSIONS: The laparoscopic approach to incisional hernia repair is a safe alternative to open repair of abdominal wall defects.

Current clinical concepts in perioperative anticoagulation.

Management of patients with significant risks for thromboembolism in the perioperative period requires consideration of both risks of thromboembolism and risks of anticoagulant therapy. Patients who are receiving warfarin therapy because of recent venous thromboembolism, nonvalvular atrial fibrillation, and mechanical heart valves are at increased risk during the interval when the warfarin is discontinued and when the international normalized ratio is at a subtherapeutic level. In patients with an acute venous thromboembolic event within the past month, the use of intravenous heparin appears to be justified both preoperatively and postoperatively. If the venous thromboembolic event was within the past 2 to 3 months, use of intravenous heparin appears justified in the postoperative period. More than 3 months after an acute episode of venous thrombophlebitis, the relatively low risk of recurrence does not appear to justify the risks of complications from intravenous heparin. Patients with increased risks of arterial embolism, specifically those with nonvalvular atrial fibrillation and mechanical heart valves, are generally not at sufficient risk of arterial embolism to justify use of intravenous heparin during the perioperative subtherapeutic international normalized ratio interval when warfarin is withheld. A potential increased risk of recurrent arterial embolism when the preceding event was within a month suggests that elective surgery should be deferred beyond a month whenever possible in such patients. The use of fixed-dose, subcutaneous low molecular weight heparin has been observed to have advantages over use of unfractionated intravenous heparin both in terms of safety and efficiency. Further refinements in management of patients with significant risks of thromboembolism may occur with increased experience with low molecular weight heparin.

Postburn vitamin C infusions do not alter early postburn edema formation.

To determine whether vitamin C would alter burn induced edema accumulation, hind paw venous pressure, lymph flow (QL), and lymph-to-plasma protein ratio (CL/CP) were monitored in groups of 5 dogs before and 4 hours after 1) a 5 sec 100 degrees C or 90 degrees C foot paw scald; 2) intravenous vitamin C given 30 min before or after a 100 degrees C scald; and 3) vitamin C given 30 min after a 90 degrees C scald. Throughout the experiments, hind paw venous pressure was elevated and maintained by outflow restriction until steady state QL and (CL/CP)min were reached. Changes in protein permeability (CL/CP), fluid conductance properties (Kf) of the capillary membrane, and paw weight gain were determined. Compared with preburn values, scald uniformly produced significant (P < .05, ANOVA) increases in QL, CL/CP and Kf. Although preburn infusion of vitamin C significantly (P < .01) attenuated burn-induced increases in paw weight gain (36 +/- 3% vs 19 +/- 4%), neither of the groups that received vitamin C postburn experienced significant modulations in paw weight gain (28 +/- 4% vs 36 +/- 3% in 100 degrees C burn only; 23 +/- 4% vs 28 +/- 3% in 90 degrees C burn only) or in any of the variables used to monitor capillary membrane integrity. Vitamin C infusions initiated after graded scald produced no changes in the burn-induced increases in microvascular permeability or in edema formation measured at the injury site.

Comparison of novel synthetic materials with traditional methods to repair exposed abdominal wall fascial defects.

Repair of large abdominal wall defects is a challenge, particularly when full-thickness tissue loss prohibits coverage of the fascial repair. Two novel synthetic materials (TMS-1 and TMS-2) have been shown to be better accepted than expanded polytetrafluoroethylene (Gore-Tex), and polypropylene (Marlex) in the closure of clean and contaminated fascial wounds that are immediately covered by skin/soft tissue. Therefore, 1-cm2 abdominal wall defects were created in each of the four quadrants of rat groups. Gore-Tex, Marlex, and TMS-1 or TMS-2 were used to repair three defects, the fourth being primarily closed. To ensure that each repair remained exposed, skin edges were sutured to underlying muscle. Additional animal groups underwent the same protocol; however, peritonitis was induced at surgery using a fecal inoculum technique. Animals were sacrificed 2 weeks later, at which time a blinded observer assessed the surface area and severity of adhesions. In clean wounds, the surface area of formed adhesions was less (p < .004) after primary closure than each synthetic material; among the synthetics, TMS-2 caused significantly (p < .01) less extensive adhesions than Marlex. In addition, the severity of adhesions to TMS-2 was comparable to that of defects closed primarily, and less severe (p < .02) than those formed to Gore-Tex and Marlex. In animals with peritonitis, primary closure caused less extensive (p < .03) adhesions than Marlex and Gore-Tex and significantly (p < .002) less severe adhesions than Marlex, Gore-Tex, and TMS-2. However, the severity of adhesions formed to TMS-1 repairs proved comparable to primarily closed wounds. These experiments reaffirm the tenet that, whenever possible, abdominal wounds should undergo primary fascial closure. When soft tissue coverage over the repair cannot be achieved, TMS-2 is well tolerated in clean wounds. However, the superiority of TMS-1 over the other synthetic materials in contaminated wounds suggests it may also ultimately prove to be of clinical utility.

Lymph isolated from a regional scald injury produces a negative inotropic effect in dogs.

Large surface-area burns in patients have been associated with a severe impairment in cardiac performance, as evidenced by a decline in cardiac output. The mechanisms responsible for this profound myocardial dysfunction are largely unknown. We investigated the effects of lymph isolated from the scalded hind limb of dogs on regional myocardial blood flow, coronary vascular reactivity, and contractile performance. Dogs were instrumented with ultrasonic dimension crystals in the myocardium supplied by the left anterior descending (LAD) and by the left circumflex (LCx) coronary arteries. After cannulating a hind limb lymphatic, lymph was infused directly into the LAD before and after a 10-second 100 degrees C hind limb scald. Scalding alone did not alter myocardial contractile performance in the LAD or LCx regions, coronary artery blood flow, or systemic hemodynamics. Interestingly, postburn lymph infused into the LAD resulted in a 38% decline in LAD zone segment shortening (p < 0.01 vs baseline) that lasted throughout the 5-hour observation period. In contrast, segment shortening in the (control) LCx region was unaffected by postburn lymph injections into the LAD. Regional myocardial blood flow (radiolabeled microspheres) in the LAD and LCx regions was unchanged after scald injury or intracoronary injection of postburn lymph. In addition, LAD coronary artery vascular reactivity to acetylcholine and nitroglycerin was also unaffected by the regional thermal injury or by injection of lymph into the LAD. These data suggest that a regional scald injury results in the production and release of a potent myocardial depressant factor(s) that produces a direct negative inotropic effect on the canine myocardium.

Efficacy of a novel synthetic material to close exposed fascial defects.

BACKGROUND: After developing a synthetic composite material (TMS-1) made from a porous polypropylene mesh (placed in apposition to fascia) coated on the "visceral" side with solid polyurethane, we compared its efficacy with that of porous polytetrafluoroethylene, polypropylene, and primary fascial closure when the repairs were left exposed to the environment. METHODS: We created 1 cm2 abdominal wall defects in each of the four abdominal quadrants of rats (n = 12). We used porous polytetrafluoroethylene, polypropylene, and TMS-1 to repair three defects; the fourth we primarily closed. The skin was left open in all cases, leaving the fascial closures exposed. A second group of rats (n = 24) had the same operation, except that peritonitis was induced using a standard fecal inoculation technique. When the rats were killed 2 weeks later, a "blinded" observer using a standard scale assessed the surface area and severity of adhesions formed. RESULTS: When compared with the other synthetic materials, the surface area of adhesions formed was significantly less after primary closure in clean conditions; in contaminated conditions, it was less than porous polytetrafluoroethylene, polypropylene, and the same as TMS-1. Furthermore, in contaminated conditions, the severity of adhesions beneath TMS-1 was the same as primary closure and significantly less than those beneath the polypropylene. CONCLUSION: The overall superiority of TMS-1 over porous polytetrafluoroethylene and polypropylene in septic conditions justifies further experiments to define its long-term efficacy in the repair of large defects.

Indomethacin-induced reduction in neonatal piglet mesenteric blood flow is blunted by dopexamine.

BACKGROUND: Dopexamine is a specific dopaminergic and beta2-adrenergic agonist. Using newborn piglets, we have previously shown that (1) dopexamine increases cardiac output and mesenteric blood flow; (2) indomethacin reduces mesenteric blood flow. METHODS: Ultrasonic blood flow probes were placed around the ascending aorta, cranial mesenteric artery, and a renal artery of 0 to 2-day-old and 2-week-old piglets. Animals of each age were grouped (5 to 8 animals per group) and subjected to one of three experimental protocols: (1) 0.4 mg/kg indomethacin infusion, (2) 10 microg/kg/min dopexamine infusion begun 10 minutes before indomethacin, or (3) no treatment. RESULTS: Control animals demonstrated no significant alterations in mesenteric blood flow. Compared with baseline, indomethacin produced significant (P< .05, analysis of variance) declines in cranial mesenteric artery blood flow in 0 to 2-day old (37.2+/-5.7 mL/min v 17.9+/-3.7 mL/min at 90 min), and 2-week-old (80.2+/-12.5 mL/min v 29.7+/-5.7 mL/min at 90 minutes) piglets. In both animal groups treated with dopexamine before indomethacin, the decreases in cranial mesenteric artery blood flow were eliminated (38.4+/-7.6 mL/min at baseline v 36.5+/-6.8 mL/min at 90 minutes in 0 to 2 day olds; 79.9+/-10.0 mL/min at baseline v 77.5+/-14.7 mL/min in 2 week olds). Indomethacin-induced declines in renal blood flow were similarly abrogated by dopexamine. CONCLUSION: Dopexamine may prove of clinical benefit when a neonate is considered a candidate for indomethacin therapy.

Development of a novel synthetic material to close abdominal wall defects.

To compare the efficacy of a novel synthetic material (TMS-2) with polytetrafluoroethylene, polypropylene (Marlex), and primary closure of experimentally fashioned clean and contaminated abdominal wounds, 1-cm2 abdominal wall defects were created in each of the four abdominal quadrants of rats (n = 10). Patches of each material were used to repair three of these defects, the fourth being primarily closed. A second group of rats (n = 7) underwent the same operative protocol; however, peritonitis was induced at the time of surgery using a fecal inoculation technique. Animals were killed 2 weeks later, and surface area and severity of formed adhesions were assessed by a "blinded" observer. All closure techniques were successful insofar as none demonstrated fascial dehiscence. Compared with each synthetic material, the surface area of formed adhesions was smaller after primary closure in clean and in contaminated conditions; however, the three synthetic materials were equally matched regarding surface area of adhesions under both conditions. In the face of fecal contamination, TMS-2 proved identical to primary closure, each generating significantly (P < 0.02) milder adhesions than the other prosthetic materials. It is concluded that the TMS-2 may prove of clinical benefit to repair abdominal wall defects.

Age-related differences in response to neutrophil-mediated reperfusion injury in the neonatal piglet heart.

BACKGROUND: Neonatal hearts have altered adhesion molecule interactions in response to ischemia-reperfusion. How this affects myocardial function is unknown. METHODS: Isolated, buffer perfused 0- to 2-day (newborn) and 2-week piglet hearts were first subjected to 20-minute global, normothermic ischemia, followed by 45 minutes of reperfusion during which 150 x 10(6) newborn or 2-week neutrophils were infused. In some hearts, an antibody to SLe(x) (CSLEX-1) was infused with neutrophils during reperfusion. Hemodynamic variables, including left ventricular developed pressure (LVDP), were recorded at timed intervals. Neutrophil CD-18, L-selectin, and SLe(x) contents were measured by flow cytometry. RESULTS: Full recovery of LVDP was observed in newborn hearts receiving newborn or 2-week-old neutrophils. Recovery of LVDP was depressed (p < 0.01, ANOVA) in 2-week-old hearts receiving 2-week old, not newborn, neutrophils. Infusion of CSLEX-1 in 2-week-old hearts restored LVDP to baseline. Whereas flow cytometry showed higher (p < 0.01, Student's t test) CD-18 and L-selectin expression on newborn versus 2-week-old neutrophils, newborn neutrophils expressed lower (p < 0.01) SLe(x) levels. CONCLUSIONS: Initial "loose" neutrophil-endothelial selectin interactions are a necessary prelude to "firm" adhesion and reperfusion injury. Operations performed soon after birth may be better tolerated than when surgery is delayed; anti-SLe(x) preparations may prove beneficial when performing cardiac procedures on older infants.

The incidence of secondary hernias diagnosed during laparoscopic total extraperitoneal inguinal herniorrhaphy.

During a 24-month period beginning in July of 1995, laparoscopic total extraperitoneal inguinal herniorrhaphy was attempted in 53 patients. All procedures were performed at a single institution, by senior-level general surgery residents, with the same attending surgeon functioning as first assistant. Three patients required conversion to an "open" procedure (all had a prior history of herniorrhaphy or lower abdominal surgery), leaving 50 patients for analysis. Preoperatively, a unilateral hernia was evident on clinical grounds in 29 patients, the remaining 21 presenting with signs of a bilateral hernia; of the total, 11 had a history of prior hernia repair on the presently affected side. At surgery, a total of 115 hernia defects (indirect, direct, femoral) were identified, 38% of which were discovered only at the time of surgery. Sixty-four percent of patients were found to have at least one of these "secondary" hernias. After reduction of the hernia(s), all defects were covered with polypropylene mesh secured with spiral tacks. There were 10 perioperative complications, one of which required corrective surgical intervention. Over 70% of patients were discharged on the day of surgery; 92% returned home within 23 h of their operation. The most common reason for delay of hospital discharge was urinary retention. There have been no recurrences in short-term follow-up. Most patients were pleased with the recovery time from and the cosmetic results of their surgery. These results suggest that laparoscopic total extraperitoneal herniorrhaphy represents a safe, effective, cosmetically appealing alternative to open hernia repair. Moreover, this approach may provide an added advantage insofar as identifying additional hernia defects that, when repaired, may ultimately yield a lower recurrence rate than might otherwise have been expected.

What's black and white and red (read) all over? The bedside interpretation of diagnostic peritoneal lavage fluid.

Diagnostic peritoneal lavage (DPL) is often used to determine whether a blunt trauma victim has significant intra-abdominal hemorrhage. One bedside test (BT) historically recommended to evaluate DPL fluid is the ability to read newsprint through the fluid contained within intravenous (i.v.) tubing. Few experimental data support this practice. Two hundred eighteen traumatologists were queried regarding their use of BTs. In a related clinical study, blinded volunteers were asked to read print through various unmarked containers filled with simulated DPL fluid, created by adding aliquots of whole human blood to liter bags of lactated Ringer's solution. Of the 97 traumatologists who completed our preliminary survey, 60 per cent reported using a visual BT to assess DPL fluid. Of these surgeons, 44 per cent attempted to read newsprint through i.v. tubing. Our clinical study showed that more volunteers could read print through a red top tube (95%) when it contained a red cell concentration of 827 +/- 41/mm3 than the i.v. bag (4%). Nearly 70 per cent of volunteers were able to read print through the tubing containing 41,429 +/- 2,967 red blood cells (RBCs)/mm3. Regardless of the receptacle, readability was lost at RBC counts far below 100,000/mm3. Many traumatologists utilize BTs as an adjunct to clinical decision making. We conclude that, if the clinician can read print through lavage fluid within an i.v. bag, Vacutainer tube, or i.v. tubing, the DPL will be negative at cell count. However, inability to read print through i.v. tubing requires laboratory confirmation to document an RBC count > 100,000/mm3.

Alpha-trinositol reduces edema formation at the site of scald injury.

BACKGROUND: The effects of alpha-trinositol (1D-myo-inositol-1,2,6-triphosphate, IP3) on burn-induced edema formation were investigated. METHODS: Lymph flow (QL; microliter/min) and lymph-to-plasma protein ratio (CL/CP) were monitored in groups of five to six dogs before and 4 hours after (1) a 5-second 100 degrees C or 90 degrees C foot paw scald; (2) IP3 (45 mg/kg intravenous bolus, then a 20 mg/kg/hr infusion) 30 minutes before or after 100 degrees C scald, or 30 minutes after 90 degrees C scald. Hind paw venous pressure was elevated and maintained by outflow restriction until reaching steady state QL and (CL/CP)min. Macromolecular reflection coefficient (1-CL/CP) was measured. Fluid filtration coefficient (Kf; ml/min/mm Hg/100 gm) was calculated. Relative paw weight gain (%) was measured. RESULTS: Compared with preburn values, scald uniformly produced significant increases in QL, CL/CP, and Kf, IP3 significantly (p < 0.02, ANOVA) reduced paw weight gain when given before, but not after, 100 degrees C burn (41% +/- 5% versus 18% +/- 7% preburn IP3 and 31% +/- 3% postburn IP3). Compared with 90 degrees C burn animals, postburn treatment significantly (p < 0.017) attenuated 4-hour increases in QL (550 +/- 87 versus 252 +/- 29 microliters/min), Kf (0.016 +/- 00 versus 0.007 +/- 00 microliter/min/mm/Hg/100 gm), and relative paw weight gain (28% +/- 3% versus 12% +/- 5%). CONCLUSIONS: alpha-Trinositol given after a 90 degrees C scald blunted edema formation at the site of scald, likely through reduced transmembrane fluid flux.