摘要:

BackgroundIncreasing the percentage of inspiratory time during mechanical ventilation (i.e., inverse inspiratory-expiratory (I:E) ventilation) is frequently used to improve oxygenation in patients with acute respiratory distress syndrome; however, an optimal I:E ratio is unknown.MethodsTo assess for an optimal I:E ratio, hemodynamic, ventilatory, and oxygenation parameters were determined in eight adult trauma patients with acute respiratory distress syndrome supported with pressure-control ventilation. An indwelling pulmonary artery catheter facilitated the extensive measurements as I:E ratios were randomly changed between 1:1 and 3:1. Measurements were determined 30 minutes after each change in the I:E ratio.ResultsIncreasing the percentage of inspiratory time resulted in a progressive increase in arterial oxygenation (p < 0.05) in conjunction with elevations in mean airway pressure (p < 0.05) and a decrease in alveolar-arterial oxygen difference (p < 0.05). Furthermore, progressive reversal of the I:E ratio significantly diminished alveolar ventilation (p < 0.01), with worsening dynamic compliance (p < 0.01). There were no demonstrable changes in hemodynamics.ConclusionThese findings demonstrate the effectiveness of increasing inspiratory time to improve oxygenation, yet to the detriment of ventilation. This suggests that within the parameter confines of this study, the preferential I:E ratio is a balance between oxygen demands and ventilatory requirements.

ISSN:0022-5282    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

BackgroundPerflubron is a perfluorocarbon with unique physical characteristics. It has twice the density of water, allows free diffusion of O2and CO2, is easily dispersed, and is insoluble. Thus, it can act as "liquid positive end-expiratory pressure" to recruit collapsed alveoli and improve oxygenation. Results of laboratory studies suggest that perflubron exerts an anti-inflammatory effect on alveolar cells. Limited clinical data in neonates and adults with severe acute respiratory distress syndrome are promising. We present a single institution's experience with partial liquid ventilation (PLV) in trauma patients compared with conventional mechanical ventilation (CMV) with particular attention to the alveolar inflammatory response.MethodsVentilated patients with bilateral lung injury and PaO2/FIO2<300 were eligible in this prospective multicenter trial. Perflubron was administered by means of the endotracheal tube to fill up to functional residual capacity ([similar]30 mL/kg), followed by supplemental doses up to 96 hours. At this institution, bronchoscopy with bronchoalveolar lavage was performed serially for white blood cell count, protein, interleukin (IL)-1, IL-6, IL-8, and IL-10, and analyzed as early (<48 hours) and late (48-96 hours). Clinical response was defined as a sustained 10% increase in PaO2/FIO2at 48 hours.Results16 patients were enrolled: 12 PLV patients and 4 CMV patients. There were no differences between groups relative to sex, Injury Severity Score, or initial PaO2/FIO2. There were no major outcome differences between groups in this pilot study relative to pneumonia (50% PLV and 75% CMV), deaths (one death in each group caused by multiple organ failure), or for oxygenation after 5 days. Eight PLV patients were responders (PLV-R) compared with four patients who did not (PLV-NR). The main differences between these subgroups was time from injury to study (1.8 days for PLV-R vs. 5.8 for PLV-NR, p < 0.02) and age (30 years for PLV-R vs. 42 years for PLV-NR, p < 0.04). Both white blood cell count and protein were higher in CMV, suggesting a greater inflammatory response. Neutrophils were significantly higher in CMV, despite equal IL-8 levels in both PLV and CMV. The inflammatory cytokines IL-1 and IL-6 were greater in CMV, and the anti-inflammatory IL-10 was lower in PLV.ConclusionEarly institution of partial liquid ventilation is effective at reducing the alveolar inflammatory response. Perflubron exhibits an anti-inflammatory effect in the alveolar environment with reduction of proinflammatory IL-1 and IL-6 (possibly removing a stimulus for IL-10), white blood cell count, and protein capillary leak. PLV also reduces alveolar neutrophils independent of IL-8. Further characterization of this altered inflammatory response is necessary.

ISSN:0022-5282    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

PurposeTo compare the effects of mechanical ventilation with either positive end-expiratory pressure (PEEP) or partial liquid ventilation (PLV) on cardiopulmonary function after severe pulmonary contusion.MethodsMongrel pigs (32 +/- 1 kg) were anesthetized, paralyzed, and mechanically ventilated (8-10 mL/kg tidal volume; 12 breaths/min; FiO2= 0.5). Systemic hemodynamics and pulmonary function were measured for 7 hours after a captive bolt gun delivered a blunt injury to the right chest. After 5 hours, FiO2was increased to 1.0 and either PEEP (n = 7) in titrated increments to 25 cm H2O or PLV with perflubron (LiquiVent, 30 mL/kg, endotracheal) and no PEEP (n = 7) was administered for 2 hours. Two control groups received injury without treatment (n = 6) or no injury with PLV (n = 3). Fluids were liberalized with PEEP versus PLV (27 +/- 3 vs. 18 +/- 2 mL[center dot]kg-1[center dot]h-1) to maintain cardiac filling pressures.ResultsBefore treatment at 5 hours after injury, physiologic dead space fraction (30 +/- 4%), pulmonary vascular resistance (224 +/- 20% of baseline), and airway resistance (437 +/- 110% of baseline) were all increased (p < 0.05). In addition, PaO2/FiO2had decreased to 112 +/- 18 mm Hg, compliance was depressed to 11 +/- 1 mL/cm H2O (36 +/- 3% of baseline), and shunt fraction was increased to 22 +/- 4% (all p < 0.05). Blood pressure and cardiac index remained stable relative to baseline, but stroke index and systemic oxygen delivery were depressed by 15 to 30% (both p < 0.05). After 2 hours of treatment with PEEP versus PLV, Po2/FiO(2) was higher (427 +/- 20 vs. 263 +/- 37) and dead space ventilation was lower (4 +/- 3 vs. 28 +/- 7%) (both p < 0.05), whereas compliance tended to be higher (26 +/- 2 vs. 20 +/- 2) and shunt fraction tended to be lower (0 +/- 0 vs. 7 +/- 4). With PEEP versus PLV, however, cardiac index, stroke index, and systemic oxygen delivery were 30 to 60% lower (all p < 0.05). Furthermore, although contused lungs showed similar damage with either treatment, the secondary injury in the contralateral lung (as manifested by intra-alveolar hemorrhage) was more severe with PEEP than with PLV.ConclusionsBoth PEEP and PLV improved pulmonary function after severe unilateral pulmonary contusion, but negative hemodynamic and histologic changes were associated with PEEP and not with PLV. These data suggest that PLV is a promising novel ventilatory strategy for unilateral pulmonary contusion that might ameliorate secondary injury in the contralateral uninjured lung.

ISSN:0022-5282    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

BackgroundThe failure of therapies aimed at modulating systemic inflammatory response syndrome and decreasing multiple organ failure (MOF) has been attributed in part to the inability to identify early the population at risk. Our objective, therefore, was to develop predictive models for MOF at admission and at 12, 24, and 48 hours after injury.MethodsLogistic regression models were derived in a data set with 411 adult trauma patients using indicators of tissue injury, shock, host factors, and the Acute Physiology Score-Acute Physiology and Chronic Health Evaluation III (APS-APACHE III).ResultsMOF was diagnosed in 78 patients (19%). Injury Severity Score, platelet count, and age emerged as predictors in all models. Transfused blood, inotropes, and lactate were significant predictors at 12, 24, and 48 hours, but not at admission. The APS-APACHE III emerged only in the 0- to 48-hour model and offered minimal improvement in predictive power. Good predictive power was achieved at 12 hours after injury.ConclusionPostinjury MOF can be predicted as early as 12 hours after injury. The APS-APACHE III added little to the predictive power of tissue injury, shock, and host factors.

ISSN:0022-5282    

出版商:OVID    

年代:1998

数据来源: OVID

ISSN:0022-5282    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

BackgroundCellular Injury Score (CIS) is an index of cellular injury, being calculated from three parameters of intracellular metabolism: arterial ketone body ratio, osmolality gap, and blood lactate.MethodsThe usefulness of CIS as a severity scoring system for patients with multiple organ failure was prospectively evaluated in 157 consecutive patients with MOF (58 survivors, 99 nonsurvivors).ResultsCISs in nonsurvivors were significantly higher compared with those in survivors throughout the clinical courses. CIS was significantly correlated with the number of failing organs and mortality rate. The optimal cutoff point of CIS from receiver operating characteristics curve analysis was 4 for the maximal value during the clinical course. The changes in CIS well reflected the severity of injury in survivors and nonsurvivors who died within 2 weeks.ConclusionCIS could be a useful index for mortality risk prediction and is potentially applicable as a severity scoring system for individual patients with MOF.

ISSN:0022-5282    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

BackgroundEnsuring an unobstructed airway and adequate oxygenation are first priorities in the resuscitation of the trauma patient. In situations of difficult endotracheal intubation, rapid sequence protocols frequently include the use of paralytic agents and cricothyrotomy for airway management. Recent literature findings suggest that the prehospital use of cricothyrotomy is too frequent. The purpose of this study was (a) to evaluate the efficacy of a rapid sequence intubation protocol without the use of paralytic agents, and (b) to determine the need for cricothyrotomy by using this protocol in the field.MethodsWe prospectively analyzed 383 acutely injured patients who were in need of airway control. Success rates, indications, and complications of endotracheal intubation and cricothyrotomy were analyzed.ResultsSuccessful orotracheal intubation on the scene with the use of this protocol was performed in 373 of 383 patients (97%). Two patients (0.5%) arrived at the trauma center with unrecognized esophageal intubation. Eight patients underwent cricothyrotomy in the field, six without previous attempts at intubation.ConclusionExperienced emergency medical services personnel can effectively perform endotracheal intubation with narcotic analgesics without the use of paralytic agents in the field. With proper training for field airway management, cricothyrotomy in the field can be reduced to a few indications with high success rates.

ISSN:0022-5282    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

BackgroundThe study of both short-term and long-term outcomes after major trauma has become an increasingly important focus of injury research because of the improved survival rates attributable to the evolution of sophisticated trauma care systems. The Trauma Recovery Project (TRP) is a large prospective epidemiologic study designed to examine multiple outcomes after major trauma in adults aged 18 years and older, including quality of life, functional outcome, and psychologic sequelae such as depression and posttraumatic stress disorder (PTSD). Patient outcomes were assessed at discharge and at 6, 12, and 18 months after discharge. The specific objectives of the present report are to describe functional outcomes at the discharge and 6-month follow-up time points in the TRP population and to examine the association of putative risk factors with functional outcome.MethodsBetween December 1, 1993, and September 1, 1996, 1,048 eligible trauma patients triaged to four participating trauma center hospitals in the San Diego Regionalized Trauma System were enrolled in the TRP study. The admission criteria for patients were as follows: (1) age 18 years or older, (2) Glasgow Coma Scale score on admission of 12 or greater, and (3) length of stay greater than 24 hours. Functional outcome after trauma was measured before and after injury using the Quality of Well-Being (QWB) scale, a more sensitive index to the well end of the functioning continuum (range, 0 = death to 1.000 = optimum functioning). Functional outcome was also measured using a standard activities of daily living (ADL) scale (range, 13 = full function to 47 = maximum dysfunction). Follow-up at 6 months after discharge was completed for 826 patients (79%).ResultsThe mean age was 36 +/- 14.8 years; 70% of the patients were male; 52% of the patients were white, 30% were Hispanic, and 18% were black or other. Less than 40% of study participants were married or living with a partner. The mean Injury Severity Score was 13 +/- 8.5, with 85% blunt injuries, and a mean length of stay of 7 +/- 9.2 days. QWB scores before injury reflected the norm for a healthy adult population (mean, 0.810 +/- 0.171). After major trauma, QWB scores at discharge showed a significant degree of functional limitation (mean, 0.401 +/- 0.045). At 6-month follow-up, QWB scores continued to show high levels of functional limitation (mean, 0.633 +/- 0.122). Limitation measured using the standard ADL scale found only moderate dysfunction at discharge (mean, 30.0 +/- 7.7) and at 6-month follow-up (mean, 15.0 +/- 4.2). Postinjury depression, PTSD, serious extremity injury, and length of stay were significant independent predictors of 6-month QWB outcome.ConclusionPostinjury functional limitation is a clinically significant complication in trauma patients at discharge and a 6-month follow-up. The QWB yields a more sensitive assessment of functional status than traditional ADL instruments. Postinjury depression, PTSD, serious extremity injury, and length of stay are significantly associated with 6-month QWB outcome.

ISSN:0022-5282    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

BackgroundPatients with repeat presentations to acute care hospitals for new injuries are trauma recidivists. Prospective identification of those patients at greatest risk will permit focusing of limited hospital prevention resources.MethodsA population-based analysis of patients with recurrent trauma presenting to all hospitals in Nevada during a 5-year period was conducted. Records of 10,355 presentations representing 10,137 patients were analyzed.ResultsRecidivist trauma patients were younger than non-recidivists, with patients aged 20 to 24 years having significantly higher rates of recidivism. Males were 1.53 times more likely than females to become recidivists. Cutting/piercing and machinery-related injuries were most frequently associated with recidivism. Cutting/piercing wound survivors were 7.06 times more likely to be recidivists than were gunshot wound survivors. Recidivists in motor vehicles crashes were 1.92 times less likely to wear seat belts than nonrecidivists. Recidivism was also significantly associated with positive blood alcohol levels and longer initial hospital stays.ConclusionThe rate of trauma recidivism in this study was 2.0%. Population-based data can be used to identify cohorts at risk of recidivism.

ISSN:0022-5282    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

BackgroundSmall pneumothoraces have been treated by observation and tube thoracostomy in asymptomatic patients. Using a rabbit model, we demonstrated previously that inspired oxygen at 60% FiO2hastened the time to resolution of complete pneumothoraces compared with room air. The present study was designed to evaluate the use of lower levels of inspired oxygen and to establish a dose-response curve for the treatment of experimental pneumothoraces.MethodsForty New Zealand White rabbits were divided randomly into four groups: room air (21%) and 30, 40, and 50% FiO2. Experimental pneumothoraces were created in the rabbits, and the animals were placed in cages with the designated level of inspired oxygen. Serial chest radiographs were performed until the pneumothoraces resolved.ResultsPneumothoraces treated with room air resolved in 61.65 +/- 12.30 hours. Those treated with 30% FiO2resolved in 42.90 +/- 5.97 hours, with 40% FiO2in 35.80 +/- 4.26 hours, and with 50% FiO2in 33.80 +/- 4.66 hours.ConclusionThese results show a statistically significant (p < 0.01) dose-dependent improvement in the resolution of pneumothoraces with increasing levels of inspired oxygen. Supplemental oxygen therapy may be used to facilitate the resolution of small, uncomplicated pneumothoraces.

ISSN:0022-5282    

出版商:OVID    

年代:1998

数据来源: OVID