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Biomedical subjects

R V Maier

Publications and source records attributed to R V Maier.

At least 91 records · Page 5Linked to original sources
PubMed1995

Trauma care systems in urban Latin America: the priorities should be prehospital and emergency room management.

Trauma is a significant cause of premature death in developing nations, but financial resources to deal with it are extremely limited. To determine which segments of a developing nation's trauma system would be most amenable to improvements, we compared management and outcome of all seriously injured patients (Injury Severity Score of > or = 9 or died) treated over 1 year by the trauma systems associated with an urban hospital in Latin America, Regional Trauma Center 21 (n = 545) in Monterrey, Mexico, and a level I trauma center in the United States, Harborview Medical Center (n = 533) in Seattle, Wash. Mortality was higher in Monterrey (55%) than in Seattle (34%, p < 0.001), because of a preponderance of prehospital and emergency room (ER) deaths. In Monterrey, 40% of seriously injured patients died in the field and 11% in the ER, compared with 21% in the field and 6% in the ER in Seattle (p < 0.001). There were significant differences in prehospital care between the two trauma systems. Scene and transport times were < 30 minutes for 47% of Monterrey cases vs. 75% in Seattle (p < 0.001). For patients with arrival blood pressure < 80, prehospital intubations had been performed on 5% of Monterrey patients vs. 79% in Seattle (p < 0.001) and en route fluid resuscitation administered to 70% of Monterrey patients vs. 99% in Seattle (p < 0.001). The observed mortality patterns indicate that priorities for trauma system improvement in urban Latin America should focus on more rapid prehospital transport and improved en route and ER resuscitation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1995

Permissive hypercapnia in trauma patients.

The use of a normal tidal volume in patients with progressive loss of alveolar airspace may increase inspiratory pressure and overdistend remaining functional alveoli. Permissive hypercapnia (PH) is a ventilator management technique that emphasizes control of alveolar pressure, rather than PCO2. The purpose of this study was to determine if the use of PH is associated with an improved outcome from adult respiratory distress syndrome (ARDS). Over a 2-year period, 39 trauma patients were treated for ARDS. Permissive hypercapnia was used in 11, and the remaining patients were treated conventionally. Demographics and risk factors were well matched in PH patients and controls. The duration of mechanical ventilation was greater in PH patients [49.2 +/- 15.2 vs. 20.8 +/- 10 days (p < 0.01)]. Survival was also greater in the PH group [91% vs. 48% (p < 0.01)]. A reduction in intensity of mechanical ventilation is associated with a prolongation of ventilatory support and an improved outcome from ARDS.

Adolescent↗
PubMed1994

Diagnostic accuracy of peritoneal lavage in patients with pelvic fractures.

OBJECTIVE: To determine the accuracy of diagnostic peritoneal lavage (DPL) for the evaluation of intraabdominal injury in patients with a pelvic fracture as a result of blunt trauma. DESIGN: Retrospective cohort analysis. SETTING: Level I trauma center in metropolitan Seattle, Wash. PATIENTS: Four hundred ninety-seven consecutive patients admitted with pelvic fractures following blunt trauma during a 60-month period. OUTCOME MEASURES: Positive results of DPL, defined by one of the following: an immediate aspiration of more than 10 mL of gross blood; a red blood cell count of more than 0.0001 x 10(12)/L; a white blood cell count greater than 0.0005 x 10(9)/L; an elevated amylase, bilirubin, or creatinine level; or organic particles or bacteria in the effluent returned after installation of 1 L of crystalloid fluid lavaged in the peritoneal cavity. RESULTS: Two hundred eighty-six patients underwent DPL. For 80 patients (28.0%), results of DPL were positive and for 194 patients (67.8%) the results of DPL were negative. For two patients (0.7%), results of DPL were false positive for a sensitivity of 94%. For another two patients (0.7%), the results of DPL were false negative for a specificity of 99%. As a diagnostic modality, DPL has a positive predictive value of 98% and a negative predictive value of 97%. CONCLUSIONS: Diagnostic peritoneal lavage is a reliable method for the evaluation of intra-abdominal injury and should remain a standard component in the evaluation of patients following blunt injury with or without pelvic fractures.

Abdominal Injuries↗
PubMed1994

Effect of interferon gamma on infection-related death in patients with severe injuries. A randomized, double-blind, placebo-controlled trial.

OBJECTIVE: To assess the efficacy of interferon gamma in reducing infection and death in patients sustaining severe injury. DESIGN: Multicenter, randomized, double-blind, placebo-controlled trial with observation for 60 days and until discharge for patients with major infection on day 60. SETTING: Nine university-affiliated level 1 trauma centers. PATIENTS: Four hundred sixteen patients with severe injuries, assessed by Injury Severity Score and degree of contamination. INTERVENTION: Recombinant human interferon gamma, 100 micrograms, was administered subcutaneously once daily for 21 days (or until patient discharge if prior to 21 days) as an adjunct to standard antibiotic and supportive therapy. MAIN OUTCOME MEASURES: Incidence of major infection, death related to infection, and death. RESULTS: Infection rates were similar in both treatment groups; however, patients treated with interferon gamma experienced fewer deaths related to infection (seven [3%] vs 18 [9%]; P = .008) and fewer overall deaths (21 [10%] vs 30 [14%]; P = .17). While 12 early deaths (days 1 through 7) occurred in each treatment group, late death occurred in 18 placebo-treated patients and nine in interferon gamma-treated patients. The results were dominated by findings at one center, which had the highest enrollment and higher infection and death rates. Statistical analysis did not eliminate the possibility of an unidentified imbalance between arms as an explanation for the results. CONCLUSION: Further evaluation is required to determine the validity of the observed reduction in infection-related deaths in patients treated with interferon gamma.

Adolescent↗
PubMed1994

Optimal therapy for stress gastritis.

OBJECTIVE: The authors compared the results of sucralfate versus H2 blocker +/- antacid as prophylaxis for stress ulceration in an intensive care unit patient population. SUMMARY BACKGROUND DATA: Stress ulceration carries high morbidity and mortality for the patient who is critically ill. Gastric acid neutralization is an effective prophylaxis. The impact of increased gastric colonization with bacterial pathogens on nosocomial pneumonia after acid neutralization is unclear. The efficacy of sucralfate prophylaxis for stress ulceration and its the effect on the nosocomial pneumonia rate is controversial. The financial implications of sucralfate prophylaxis versus H2 blocker-based acid neutralization therapy has not been studied. METHODS: Ninety-eight injured patients who were critically ill and who required intubation and intensive care unit (ICU) support for at least 72 hours without gastric feeding were randomized and received either maximal H2 blocker infusion therapy (continuous infusion of ranitidine at 0.25 mg/kg/hr after a loading dose of 0.5 mg/kg) plus antacids (for persistent pH < 4) or sucralfate (1 g every 6 hours via nasogastric tube) for stress ulcer prophylaxis. Efficacy in preventing stress ulcer complications was determined. The impact of each therapeutic approach on development of nosocomial pneumonia was evaluated. The charges/cost for each approach was analyzed. RESULTS: Heme-positive gastric aspirates occurred in 99% of the patients, whereas 12 (7 in the H2 blocker group and 5 in the sucralfate group) were grossly positive for blood. However, only one from each group required transfusion, and one in the H2 blocker group required operation. Gastric colonization preceded tracheobronchial colonization in five patients in the H2 blocker group and one patient in the sucralfate group; simultaneous gastric/oropharyngeal colonization preceded positive tracheobronchial growth in six patients who received H2 blocker and one patient who received sucralfate. The overall pneumonia rate was 27.5% in the H2 blocker group and 20.8% in the sucralfate group (p = 0.48). Days on ventilator were 13.5 versus 9.1, (p = 0.06), ICU lengths of stay were 14.7 versus 10.2 (p = 0.06), and hospital lengths of stay were 27.8 versus 20.0 (p = 0.029) for the H2 blocker group and sucralfate group, respectively. Based on current charges and protocols for optimal H2 blocker and sucralfate prophylaxis, use of sucralfate rather than H2 blockers would decrease the annual cost by more than $30,000 per bed. CONCLUSIONS: Sucralfate is as efficacious as maximal H2 blocker therapy for stress ulceration prophylaxis, and may have a beneficial effect on the incidence of nosocomial pneumonia. Sucralfate has a major reduction on nursing requirements for stress ulcer prophylaxis and would save approximately $30,000 per ICU bed per year in patient charges.

Adult↗
PubMed1994

The impact of hypothermia on dilutional coagulopathy.

UNLABELLED: The control of hemorrhage in hypothermic patients with platelet and clotting factor depletion is often impossible. Determining the cause of coagulopathic bleeding (CB) will enable physicians to appropriately focus on rewarming, clotting factor repletion, or both. OBJECTIVE: To determine the contribution of hypothermia in producing CB and ascertain if simultaneous hypothermia and dilutional coagulopathy (DC) interact synergistically. METHOD: Prothrombin time, partial thromboplastin time, and platelet function were determined at assay temperatures of 29 degrees to 37 degrees C on normal and critically ill, noncoagulopathic (NC) individuals. Dilutional coagulopathy was created using buffered saline and the assays repeated. RESULTS: Hypothermic assay at < or = 35 degrees C significantly prolonged coagulation times. The effect of hypothermia on NC and DC samples was not different. CONCLUSION: Assays performed at 37 degrees C underestimate coagulopathy in hypothermic patients. The effect of hypothermia on NC and DC is not different, indicating the lack of a synergistic effect. Normalization of clotting requires both rewarming and clotting factor repletion.

Adolescent↗
PubMed1993

Interferon-gamma: a key immunoregulatory lymphokine.

Interferon-gamma is an important component of numerous host responses to inflammatory insults. Data from in vitro and animal studies suggest that this agent may have clinical uses in immunocompromised patients who are at increased risk for infectious complications. In addition to reviewing our current understanding of the in vitro and in vivo actions of interferon-gamma, this article cautions that the potential for adverse reactions exists when interferon-gamma is administered to an immunologically competent host.

Endothelium, Vascular↗
PubMed1993

A retrospective cohort study of seatbelt use and pregnancy outcome after a motor vehicle crash.

To determine the effect of seatbelt use on pregnancy outcome we conducted a population-based retrospective cohort study of pregnant women (20 weeks' gestation or more) involved in motor vehicle collisions. Birth and fetal death certificates were obtained for 1243 restrained and 1349 unrestrained pregnant women involved in police-investigated motor vehicle crashes from 1980 through 1988. Unrestrained pregnant women drivers were 1.9 times more likely to have a low birth weight baby (95% confidence intervals = 1.2, 2.9) and 2.3 times more likely to give birth within 48 hours after the motor vehicle crash (95% confidence intervals = 1.1, 4.8) than restrained pregnant women drivers after adjusting for age and gestational age at crash. Although a trend for an increased risk of fetal deaths was observed among unrestrained women, too few fetal deaths occurred to accurately describe any association with restraint status. This study provides reassurance that the current recommendations on use of seatbelts by pregnant women are appropriate and should be continued.

Accidents, Traffic↗
PubMed1993

Prostaglandin E2 mediates lipopolysaccharide-induced macrophage procoagulant activity by a cyclic adenosine monophosphate-dependent pathway.

BACKGROUND: Multiple organ failure syndrome (MOFS) and adult respiratory distress syndrome (ARDS) continue to be significant clinical problems. Microvascular thrombosis and intraalveolar fibrin deposition play an integral role in the pathogenesis of MOFS and ARDS. The macrophage participates in these processes by expressing procoagulant activity (PCA) after exposure to endotoxin. One potential method to ameliorate organ dysfunction in ARDS and MOFS is to prevent macrophage activation of the coagulation cascade. Because inhibitors of arachidonic acid metabolism attenuate inflammatory lung injury, we investigated the role of eicosanoids in endotoxin-induced alveolar macrophage PCA. METHODS: Rabbit alveolar macrophages were incubated with selective inhibitors of arachidonic acid metabolism. PCA was determined in cell lysates. PCA was also assessed in cultures treated with cyclooxygenase inhibitor that had exogenous prostaglandin E2 (PGE2) added. Intracellular cyclic adenosine monophosphate (cAMP) was examined after treatment with lipopolysaccharide, ibuprofen, PGE2, and forskolin. RESULTS: Ibuprofen significantly reduces lipopolysaccharide-stimulated PCA by alveolar macrophages. 5-Lipoxygenase and thromboxane synthetase inhibitors had no effect on PCA. Inhibition of PCA by ibuprofen is reversed by adding exogenous PGE2. Decreased intracellular cAMP is associated with attenuated lipopolysaccharide-stimulated PCA elaboration. CONCLUSIONS: Endotoxin-stimulated alveolar macrophage PCA is prostanoid dependent, with cAMP acting as a second messenger. Although expression of PCA is prostanoid-cAMP dependent, neither prostanoids nor agents that directly increase cAMP are sufficient to elicit PCA in the absence of lipopolysaccharide.

1-Methyl-3-isobutylxanthine↗
PubMed1992

Analysis of surgical participation in the Advanced Trauma Life Support course. What are the goals and are we meeting them?

Advanced Trauma Life Support (ATLS) course records spanning 4 years were examined and American College of Surgeons members in Washington State surveyed to gain further information on ATLS course participants, skills utilization, and hospital credentialing. Thirty-seven (9.7%) of 382 course participants were trained general surgeons, 56 (14.7%) were surgical residents, and 12 (3.1%) were surgical specialists. One hundred thirty-six (35.6%) of the participants were primary care physicians and 115 (30.1%) were emergency physicians. Surgical residents, primary care physicians, and emergency physicians tended to be overrepresented in ATLS courses in comparison with their general distribution. Fully trained surgeons and surgical specialists were underrepresented. Course participants represented 3.8% of all physicians involved in patient care in the state. Only 6.4% of all active general surgeons in the state were participants, while 39% of active emergency physicians participated. The successful completion rate was 94% (98% for surgeons and 92% for nonsurgical physicians). Thirty-one percent of all American College of Surgeons survey respondents (31% of urban practitioners and 21% of rural practitioners) reported current ATLS qualification. Advanced Trauma Life Support qualification was reported by 31% of respondents as a requirement for taking trauma/emergency department call. Surgeons with a preference not to treat patients with trauma were less likely to have ATLS qualification. More than half of those who reported ATLS qualification had not performed a tracheal intubation, cricothyroidotomy, pericardiocentesis, or emergency department thoracotomy in the previous year. Participation of surgeons in ATLS courses is low, particularly among rural practitioners. Impetus for participation appears related to requirements for hospital staff credentialing and preferences for treating patients with trauma. Performance of procedures taught in the course is rare. Strategies to increase participation need to be formulated and implemented.

Education, Medical, Continuing↗
PubMed1992

Macrophage priming by interferon gamma: a selective process with potentially harmful effects.

The tissue-fixed macrophage is a key cellular element in the initiation and regulation of inflammation. Understanding the regulation of macrophage activation may provide valuable clues to the mechanisms involved in both beneficial and deleterious effects of inflammation. The lymphokine interferon-gamma (IFN-gamma) is capable of producing paradoxical immunoinflammatory effects. In the immunocompromised host it up-regulates a variety of immune functions and improves survival, but it is also capable of producing harmful effects by sensitizing immunocompetent animals to subclinical doses of endotoxin. These paradoxical effects suggest that the state of activation or priming of the host immune system is a key determinant of its response to endotoxemia. Because tumor necrosis factor (TNF) and procoagulant activity (PCA) elaboration by the tissue-fixed macrophage play a central role in the host response to endotoxin, we asked whether the paradoxical effects of IFN-gamma may be caused by priming of the macrophage for TNF and/or PCA production. In vitro, IFN-gamma produces a marked augmentation in TNF but does not alter PCA elaboration in response to endotoxin, demonstrating the selectivity of IFN-gamma priming of the macrophage. In vivo, IFN-gamma pretreatment followed by an established subclinical endotoxin exposure enhances toxicity while simultaneously increasing peak serum TNF levels. Exogenous priming by IFN-gamma alters the activation state of the macrophage and modifies the host response to endotoxin. Because this response is also dependent on the host's underlying immune state, IFN-gamma treatment in the immunocompetent host has the potential to produce deleterious effects by eliciting an exaggerated TNF response during endotoxemia.

Animals↗
PubMed1992

Liposome-encapsulated hemoglobin inhibits tumor necrosis factor release from rabbit alveolar macrophages by a posttranscriptional mechanism.

Macrophages contribute to the systemic inflammatory response that characterizes the sepsis syndrome through the production of inflammatory cytokines such as tumor necrosis factor (TNF). Liposome-encapsulated hemoglobin (LEH), a potential red cell substitute, is cleared by fixed tissue macrophages. In these studies, in vitro incubation of alveolar macrophages with stored LEH was shown to inhibit the expression of TNF induced by endotoxin (lipopolysaccharide, LPS) stimulation. This effect was dependent on LEH dose but independent of the period of exposure to the LEH. Despite inhibition of TNF expression, Northern blot analysis of total cellular RNA from LPS-stimulated macrophages revealed accumulations of TNF-specific transcripts in cells treated with or without LEH. Thus the mechanism of LEH inhibition of TNF expression appears to involve a posttranscriptional event. Although these results suggest a potential advantage of resuscitation with LEH when sepsis complicates hemorrhagic shock, immunomodulation in vivo remains to be defined.

Animals↗
PubMed1992

Resuscitative thoracotomy performed in the operating room.

The efficacy of resuscitative thoracotomy in the trauma patient has been questioned. Survival rates are variable, but a review of resuscitative thoracotomy in the emergency department of our institution documented an overall survival rate of only 1.8%. Higher survival rates may be anticipated in patients initially presenting with signs of life who can be transported directly to the operating room prior to the need for resuscitative thoracotomy. To test this hypothesis, the clinical course of all injured patients undergoing urgent or exigent thoracotomy in the operating room between July 1983 and June 1989 was reviewed. There were 34 patients undergoing exigent/resuscitative thoracotomy, 8 with penetrating injuries, 25 with blunt trauma to multiple systems, and 1 with isolated blunt chest trauma. Eight median sternotomies were performed and 26 left or bilateral thoracotomies. Twenty-six patients underwent concurrent exploratory celiotomy. The overall survival rate was 9% (3 of 34). The survival rate for patients with penetrating injuries was 37.5% (3 of 8) and 0% (0 of 26) for those with blunt trauma. Fifty-four patients underwent urgent/nonresuscitative thoracotomy with an overall survival rate of 74% (40 of 54). Combined group survival rates were 49% overall, 77% for patients with penetrating wounds, and 22% for patients with blunt trauma. These data underscore the futility of resuscitative thoracotomy in patients with blunt trauma who have deteriorated to the point of being in extremis. The relatively high salvage rates in patients with penetrating injuries support continued use of resuscitative thoracotomy when vital signs are lost, particularly if the injury is to the thorax. Variability in reported survival rates may be primarily due to the mix of patients with blunt trauma and penetrating injuries and disagreement as to what constitutes a resuscitative thoracotomy.

Adolescent↗
PubMed1992

Platelet-activating factor augments tumor necrosis factor and procoagulant activity.

Infusion of platelet activating factor (PAF) reproduces the host physiologic response to endotoxemia and sepsis. Tumor necrosis factor (TNF) and procoagulant activity (PCA) are two other potentially deleterious central inflammatory mediators produced in large quantities by tissue-fixed macrophages (M phi). The relationship, if any, between PAF and TNF or PCA production is unknown. Rabbit alveolar M phi were treated in vitro with PAF alone and prior to endotoxin (LPS). PAF alone had no effect on M phi PCA or TNF. PAF (10(-9)-10(-6) M) cotreatment enhanced M phi PCA and TNF levels in a dose response from two- to sixfold above that of LPS treatment alone. PAF (10(-6) M) pretreatment of M phi at T -4 to -6 hr produces an eight- to ninefold enhancement in both TNF and PCA levels. Thus, both coincubation and pretreatment or "priming" of the M phi with PAF prior to LPS stimulation greatly increase M phi production of PCA and TNF. The ability to augment the production of these two potent inflammatory mediators may explain in part the mechanism of action of PAF in vivo.

Animals↗
PubMed1992

State trauma system evaluation: a unique and comprehensive approach.

We detail the unique and comprehensive approach to evaluation taken by the state of Washington before development and legislation of a statewide trauma system plan. The various types of data collected and the rationale for collecting them are discussed. In addition, the advantages, disadvantages, and limitations of individual study methods are elucidated. These data-gathering approaches may serve as a guide for other states or regions contemplating comprehensive trauma system development.

Data Collection↗
PubMed1992

The impact of motorcycle helmet use.

Mandatory motorcycle helmet-use legislation is supported by the high morbidity of motorcycle trauma and its cost to society. Opponents argue, however, that the majority of motorcycle trauma morbidity and costs are the result of injuries to body regions other than the head. Previous data do not address this argument because they fail to control for differences in non-head injury severity (i.e., kinetic impact) between helmeted and unhelmeted patients. This study investigates the impact of helmet use on the morbidity and cost of motorcycle trauma, after controlling for non-head injuries. A retrospective review of all patients admitted to Harborview Medical Center with motorcycle trauma from 1/1/85 to 1/1/90 was performed. Non-head injury severity was determined by calculating an ISS that did not include head injury. This non-head ISS was used to control for injury severity below the neck. Four hundred twenty-five patients were identified. Stratified analysis showed that helmet use decreased the need for and duration of mechanical ventilation, the length of ICU stay, the need for rehabilitation, and prevented head injury. Costs of acute care were significantly less in helmeted patients. Regression analysis, controlling for age, gender, and blood alcohol level (as well as non-head injury severity), confirmed that acute costs were 40% less with helmet use.

Adult↗
PubMed1992

Nutritional assessment using a pulmonary artery catheter.

To determine if oxygen consumption (VO2) derived from the Fick equation (FE) can be used to determine energy expenditure (EE), 29 paired indirect calorimetry (IC) and FE VO2 determinations were obtained. The Weir equation was used to calculate EE from the FE VO2 value. There was a strong correlation between the methods (r = 0.82, p less than 0.001). Mean EE by IC and FE was 2460 +/- 539 and 2372 +/- 787 kcal/day, respectively, a difference of 88 +/- 467 kcal/day. A single IC determination is often used to guide nutrition for several days. To evaluate this practice, FE and IC determinations were repeated in 8 patients. There was a 19% difference in EE between initial and follow-up IC, which was identical to the mean difference between paired FE and IC measurements. FE can be used to estimate EE, and is as accurate as using a single IC reading to predict EE on subsequent days.

Adult↗