Circulating progenitor cells in patients with familial hypercholesterolemia.

OBJECTIVE: Familial hypercholesterolemia (FH) is a genetic disease with very high levels of circulating low density lipoprotein cholesterol (LDL-C) levels that leads to accelerated atherosclerosis. Lipoprotein apheresis is an effective treatment option for patients with FH and results in reduced cardiovascular morbidity and mortality. Circulating progenitor cells (CPCs) are markers of overall vascular health and diminished levels have been associated with decreased reparative potential and worse outcomes. We assessed the short-term change in CPC levels following a single lipoprotein apheresis session in FH patients who are already on stable lipoprotein apheresis therapy. We hypothesized that in addition to a reduction in atherogenic lipids, the cardiovascular benefit from lipoprotein apheresis therapy is mediated by enhanced vascular reparative capacity through mobilization of CPCs. METHODS: Eight FH patients (1 homozygous and 7 heterozygous) on stable lipoprotein apheresis therapy for at least three months had CPCs measured at baseline (prior to apheresis) and two hours after apheresis. Results were compared with data from age-matched hyperlipidemic (HLP) patients on statin therapy and healthy volunteers. RESULTS: FH patients had higher baseline circulating levels of CD34+/CD133+ and CD34+/CD133+/CXCR4+ cells compared to HLP and healthy subjects. There was no significant change in CPCs after apheresis in FH patients. CONCLUSIONS: FH patients had higher CPC counts at baseline compared to age-matched HLP and healthy controls, suggesting activation of reparative mechanism in this high risk population. Larger studies are needed to better characterize differences in CPC counts between FH subjects and HLP patients over time.

Economic burden and health-related quality of life associated with Prader-Willi syndrome in France.

BACKGROUND: To date, there has been no published comprehensive estimation of costs related to Prader-Willi syndrome (PWS). Our objective was therefore to provide data on the economic burden and health-related quality of life associated with PWS in France in order to raise awareness of the repercussions on individuals suffering from this syndrome and on caregivers as well as on the health and social care systems. METHOD: A retrospective cross-sectional study was carried out on 51 individuals recruited through the French PWS patient association. Data on their demographic characteristics and resource use were obtained from an online questionnaire, and costs were estimated by a bottom-up approach. The EQ-5D-5L health questionnaire was used to measure the health-related quality of life of individuals suffering from PWS and their caregivers. RESULTS: The average annual cost of PWS was estimated at €58 890 per individual, with direct healthcare accounting for €42 299, direct non-healthcare formal costs €13 865 and direct non-healthcare informal costs €8459. The main contributors to PWS costs were hospitalisations and social services. Indirect costs resulting from loss of productivity in the labour market was €32 542 for adults suffering from PWS. Mean EQ-5D utility scores were 0.4 for individuals with PWS and 0.7 for caregivers. CONCLUSIONS: Prader-Willi syndrome represents a major economic burden from a societal perspective and has a significant impact on health-related quality of life both for individuals suffering from PWS and for their caregivers in France. These results underscore the need to develop tailored policies targeted at improving care. Likewise, a larger study collecting a broader range of medical characteristics should be undertaken to achieve more precise estimations.

The economic burden and health-related quality of life associated with systemic sclerosis in France.

OBJECTIVES: To provide data on the economic burden and health-related quality of life (HRQoL) associated with systemic sclerosis (SSc) in France and to raise awareness of the repercussions of this disease for patients and caregivers and on the health and social care system. METHOD: A cross-sectional study was carried out on 147 patients recruited through the Association des Sclérodermiques de France (ASF), the French association for SSc patients. Data on the patients' use of resources were obtained retrospectively from an online questionnaire and costs were estimated by a bottom-up approach. The HRQoL patients and caregivers was assessed with the five-level EURQol-5 Dimension (EQ-5D-5L) health questionnaire. RESULTS: The average annual cost of SSc was estimated at EUR 22,459 per patient. Direct healthcare costs amounted to EUR 8452, direct non-healthcare formal costs to EUR 1606, direct non-healthcare informal costs to EUR 1875, and indirect costs resulting from patients' absence from the labour market to EUR 10,526. The main contributors to SSc costs were hospitalizations and early retirement. Mean EQ-5D utility scores were 0.49 for patients and 0.66 for caregivers. CONCLUSIONS: Although SSc is a rare disease, its economic burden from a societal perspective is substantial and the consequences for HRQoL are significant for both patients and caregivers in France, underscoring the need to develop tailored policies targeted at improving patients' care and reducing the long-term impact of SSc.

Fragile X syndrome: economic burden and health-related quality of life of patients and caregivers in France.

BACKGROUND: Fragile X syndrome (FXS) is the main hereditary cause of intellectual disability. Although the associated burden appears to be considerable, to date no study has comprehensively assessed the cost incurred because of FXS, including its specific impact on health-related quality of life and the burden on caregivers using standardised quantitative tools. The aim of this article is to provide data in order to increase awareness of the repercussions of FXS on patients and caregivers as well as on the health and social care systems in France. METHODS: A retrospective cross-sectional study was carried out on 145 patients recruited through Le Goëland X-Fragile and Mosaïques, the French FXS patient associations. Data on their demographic characteristics and resource use were obtained from an online questionnaire, and costs were estimated by a bottom-up approach. The EQ-5D health questionnaire was used to measure patients' and caregivers' health-related quality of life. Perceived burden of care was measured using the Zarit Caregiver Burden Interview. The Barthel index, a non-utility-based assessment, was used to measure patients' level of dependence. RESULTS: The annual total direct cost of FXS was estimated at €25 800 per patient. The main contributors were informal care provided by the main caregiver (€10 500) and social services (€8400). Healthcare costs, estimated at €2700, represented only a minor share. Mean EQ-5D utility scores were 0.49 for patients and 0.75 for caregivers. The mean burden for caregivers as measured by the Zarit Caregiver Burden Interview was 39.9. CONCLUSIONS: Fragile X syndrome requires significant resources that are mainly of a non-medical nature and are higher for children than for adults. Compared with related diseases, it constitutes a particularly high burden for caregivers. Using a bottom-up approach and a wide range of standardised measures, this study underscores the need for greater awareness of the burden of FXS as well as an assessment of new and existing interventions to address it.

The diversity of regulation and public financing of IVF in Europe and its impact on utilization.

STUDY QUESTION: How do the different forms of regulation and public financing of IVF affect utilization in otherwise similar European welfare state systems? SUMMARY ANSWER: Countries with more liberal social eligibility regulations had higher levels of IVF utilization, which diminished as the countries' policies became more restrictive. WHAT IS KNOWN ALREADY: Europe is a world leader in the development and utilization of IVF, yet surveillance reveals significant differences in uptake among countries which have adopted different approaches to the regulation and and public financing of IVF. STUDY DESIGN, SIZE, DURATION: A descriptive and comparative analysis of legal restrictions on access to IVF in 13 of the EU15 countries that affirmatively regulate and publicly finance IVF. PARTICIPANTS/MATERIALS, SETTING, METHODS: Using 2009 data from the European Society of Human Reproduction and Embryology study of regulatory frameworks in Europe and additional legislative research, we examined and described restrictions on access to IVF in terms of general eligibility, public financing and the scope of available services. Multiple correspondence analysis was used to identify patterns of regulation and groups of countries with similar regulatory patterns and to explore the effects on utilization of IVF, using data from the most recent European and international IVF monitoring reports. MAIN RESULTS AND THE ROLE OF CHANCE: Regulations based on social characteristics of treatment seekers who are not applicable to other medical treatments, including relationship status and sexual orientation, appear to have the greatest impact on utilization. Countries with the most generous public financing schemes tend to restrict access to covered IVF to a greater degree. However, no link could be established between IVF utilization and the manner in which coverage was regulated or the level of public financing. LIMITATIONS, REASONS FOR CAUTION: Owing to the lack of data regarding the actual level of public versus private financing of IVF it is impossible to draw conclusions regarding equity of access. Moreover, the regulatory and utilization data were not completely temporally matched in what can be a quickly changing regulatory landscape. WIDER IMPLICATIONS OF THE FINDINGS: Whether motivated by cost, eligility restrictions or the availability of particular services, cross-border treatment seeking is driven by regulatory policies, underscoring the extra-territorial implications of in-country political decisions regarding access to IVF. STUDY FUNDING/COMPETING INTEREST(S): There was no funding source for this study. The authors have no conflicts of interest to declare.

Multicenter validation of a simplified score to predict massive transfusion in trauma.

BACKGROUND: Several studies have described predictive models to identify trauma patients who require massive transfusion (MT). Early identification of lethal exsanguination may improve survival in this patient population. The purpose of the current study was to validate a simplified score to predict MT at multiple Level I trauma centers. METHODS: All adult trauma patients treated at three Level I trauma centers from July 2006 to June 2007 who (1) were transported directly from the scene, (2) were trauma activations, and (3) received any blood transfusions during admission were included. Assessment of Blood Consumption (ABC) score developed using the same inclusion criteria for patients admitted to a single trauma center (Vanderbilt University Medical Center [VUMC]-1) between July 2005 and June 2006. ABC score calculated by assigning a value (0 or 1) to each of the four parameters: penetrating mechanism, positive focused assessment with sonography for trauma for fluid, arrival blood pressure <90 mm Hg, and arrival pulse >120 bpm. A score of 2 was used as "positive" to predict MT. Area under receiver-operating characteristic curve was calculated to compare the predictive ability of the score at each institution. RESULTS: There were 586 patients in the developmental (VUMC-1), 513 patients at trauma center 1 (VUMC-2), 372 at trauma center 2 (PMH), and 133 at trauma center 3 (Johns Hopkins Hospital). MT rate was similar between centers: 14% to 15%. Sensitivity and specificity for the ABC score predicting MT ranged from 75% to 90% and 67% to 88%, respectively. Correctly classified patients and area under receiver-operating characteristic curve, however, were 84% to 87% and 0.83 to 0.90, respectively. CONCLUSIONS: The ABC score is a valid instrument to predict MT early in the patient's care and across various demographically diverse trauma centers. Future research should focus on this score's ability to prospectively identify patients who will receive MT.

Modern Results of Functional Bracing of Humeral Shaft Fractures: A Multicenter Retrospective Analysis.

OBJECTIVES: To evaluate the rate of, and reasons for, conversion of closed treatment of humeral shaft fractures using a fracture brace, to surgical intervention. DESIGN: Multicenter, retrospective analysis. SETTING: Nine Level 1 trauma centers across the United States. PATIENTS: A total of 1182 patients with a closed humeral shaft fracture initially managed nonoperatively with a functional brace from 2005 to 2015 were reviewed retrospectively from 9 institutions. INTERVENTION: Functional brace. MAIN OUTCOME MEASUREMENTS: Conversion to surgery. RESULTS: A total of 344 fractures (29%) ultimately underwent surgical intervention. Reasons for conversion included nonunion (60%), malalignment beyond acceptable parameters (24%), inability to tolerate functional bracing (12%), and persistent signs of radial nerve palsy requiring exploration (3.7%). Univariate comparisons showed that females and whites were significantly (P < 0.05) more likely to be converted to surgery. The multivariate logistic regression identified females as being 1.7 times more likely and alcoholics to be 1.4 times more likely to be converted to surgery (P < 0.05). Proximal shaft as well as comminuted, segmental, and butterfly fractures were also linked to a higher rate of conversion. CONCLUSIONS: This large multicenter study identified a 29% surgical conversion rate, with nonunion as the most common reason for surgical intervention after the failure of functional brace. These results are markedly different than previously reported. These results may be helpful in the future when counseling patients on the choice between functional bracing and surgical intervention in managing humeral shaft fractures. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Hyperkalemia following massive transfusion in trauma.

BACKGROUND: Large-volume blood transfusions have been implicated in the development of hyperkalemia. The purpose of the current study was to determine whether critically injured patients receiving massive transfusions are at an increased risk of hyperkalemia. METHODS: Massive transfusion (MT) cohort, all trauma patients (02/2004-01/2008) taken directly to the OR and receiving >or=10 units of RBC in first 24h. Comparison cohort (No-RBC), all patients (02/2004-01/2008) transported directly to the OR who received no blood products in the first 24h. Hyperkalemia defined as K+ > 5.5 mEq/L. RESULTS: There were 266 MT patients, 237 No-RBC patients. MT patients were more likely to have hyperkalemia in the immediate postoperative setting (1.8% versus 4.6%, P = 0.049). However, linear regression did not identify intraoperative blood transfusions as a predictor of postoperative K+ values (P = 0.417). Logistic regression identified only preop K+ (OR 1.79, P = 0.021) and postop pH (OR 0.009, P = 0.001), but not MT, as independent risk factors for postop hyperkalemia. CONCLUSIONS: Despite concerns of hyperkalemia following MT, we found less than a 5% incidence of postop K+ (>5.5 mEq/L). After adjusting for the significant effects of preop K+ and postop pH, MT patients were at no higher risk of hyperkalemia than those who received no blood products.

Predefined massive transfusion protocols are associated with a reduction in organ failure and postinjury complications.

INTRODUCTION: Massive transfusion (MT) protocols have been shown to improve survival in severely injured patients. However, others have noted that these higher fresh frozen plasma (FFP):red blood cell (RBC) ratios are associated with increased risk of organ failure. The purpose of this study was to determine whether MT protocols are associated with increased organ failure and complications. METHODS: Our institution's exsanguination protocol (TEP) involves the immediate delivery of products in a 3:2 ratio of RBC:FFP and 5:1 for RBC:platelets. All patients receiving TEP between February 2006 and January 2008 were compared with a cohort (pre-TEP) of all patients from February 2004 to January 2006 that (1) went immediately to the operating room and (2) received MT (>or=10 units of RBC in first 24 hours). RESULTS: Two hundred sixty-four patients met inclusion (125 in the TEP group, 141 in the pre-TEP). Demographics and Injury Severity Score were similar. TEP received more intraoperative FFP and platelets but less in first 24 hours (p < 0.01). There was no difference in renal failure or systemic inflammatory response syndrome, but pneumonia, pulmonary failure, open abdomens, and abdominal compartment syndrome were lower in TEP. In addition, severe sepsis or septic shock and multiorgan failure were both lower in the TEP patients (9% vs. 20%, p = 0.011 and 16% vs. 37%, p < 0.001, respectively). CONCLUSIONS: Although MT has been associated with higher organ failure and complication rates, this risk appears to be reduced when blood products are delivered early in the resuscitation through a predefined protocol. Our institution's TEP was associated with a reduction in multiorgan failure and infectious complications, as well as an increase in ventilator-free days. In addition, implementation of this protocol was followed by a dramatic reduction in development of abdominal compartment syndrome and the incidence of open abdomens.

Room for (performance) improvement: provider-related factors associated with poor outcomes in massive transfusion.

BACKGROUND: Massive transfusion (MT) protocols improve survival in patients with exsanguinating hemorrhage. Both the increased plasma to red blood cells (RBC) and platelets to RBC ratios, and the "protocolization" of product delivery seem to be critical components of the reduction in mortality. The purpose of this study was to identify the incidence and impact of MT protocol noncompliance and to intervene in provider-related events associated with poor compliance and outcomes. METHODS: A MT protocol was initiated in 2006 at a Level I trauma center. All cases of protocol activation were reviewed by a multidisciplinary performance improvement (PI) group for compliance and the need for "real-time" protocol adjustments. Educational conferences, Grand Rounds presentations, and individual provider education were performed on a quarterly basis. Compliance of seven measures were evaluated as follows: type and screen sent from emergency department (ED), activation of protocol in ED, activation by trauma attending, administration of 2:3 plasma to RBC, administration of 1:5 platelets to RBC, protocol discontinuation on leaving operating room, and no products wasted. Univariate, multivariate, and time-series analyses were performed. RESULTS: All 125 MT protocol activations occurring from February 2006 to January 2008 were reviewed. Full compliance for all PI measures during the entire period was 27%. There were no differences in demographics, injury severity, or physiologic scores between patients for whom activations were compliant and those who were noncompliant. Full compliance was an independent predictor of survival (86.7% vs. 45.0%, p < 0.001). Both activation of the protocol in the ED and achievement of prespecified ratios of plasma: RBC (2:3) and platelets: RBC (1:5) were independent predictors of 24-hour and 30-day survivals. All PI measures demonstrated improved compliance during the study period with the exception of ED activation. Failure to send type and screen from the ED is an independent predictor of wasted blood products. CONCLUSION: Early activation of a MT protocol and achieving predefined ratios was associated with improved survival. ED activation and direct blood bank notification by the trauma attending were associated with a reduction in blood product wastage. A multidisciplinary PI process helps to identify provider/specialty noncompliance and to assess the impact of these factors, and it was associated with improvement in compliance and MT outcomes over time.

Optimizing outcomes in damage control resuscitation: identifying blood product ratios associated with improved survival.

BACKGROUND: Despite recent attention and impressive results with damage control resuscitation, the appropriate ratio of blood products to be transfused has yet to be defined. The purpose of this study was to evaluate whether suggested blood product ratios yield superior survival rates. MATERIALS: After IRB approval, a retrospective evaluation was performed on all trauma exsanguination protocol (TEP, n = 118) activations from February 1, 2006 to July 31, 2007. A comparison cohort (pre-TEP, n = 140) was selected from all trauma admissions between August 1, 2004 and January 31, 2006 that (1) underwent immediate surgery by the trauma team and (2) received greater than 10 units of PRBC in the first 24 hours. We then compared those who received FFP:RBC (2:3) and platelet:RBC (1:5) ratios with those who did not reach these ratios. Multivariate analysis was performed for independent predictors of mortality. RESULTS: A total of 259 patients were available for study. Patients receiving FFP:RBC at a ratio of 2:3 or greater (n = 64) had a significant reduction in 30-day mortality compared with those who received less than a 2:3 ratio (n = 195); 41% versus 62%, p = 0.008. Patients receiving platelets:RBC at a ratio of 1:5 or greater (n = 63) had a lower 30-day mortality when compared with those with who received less than this ratio (n = 196); (38% vs. 61%, p = 0.001). Regression model demonstrated that a ratio of FFP to PRBC is an independent predictor of 30-day mortality, controlling for age and TRISS (OR 1.78, 95% CI 1.01-3.14). CONCLUSIONS: Increased FFP:PRBC and PLT:PRBC ratios during a period of massive transfusion improved survival after major trauma. Massive transfusion protocols should be designed to achieve these ratios to provide maximal benefit.

Damage control hematology: the impact of a trauma exsanguination protocol on survival and blood product utilization.

BACKGROUND: The importance of early and aggressive management of trauma- related coagulopathy remains poorly understood. We hypothesized that a trauma exsanguination protocol (TEP) that systematically provides specified numbers and types of blood components immediately upon initiation of resuscitation would improve survival and reduce overall blood product consumption among the most severely injured patients. METHODS: We recently implemented a TEP, which involves the immediate and continued release of blood products from the blood bank in a predefined ratio of 10 units of packed red blood cells (PRBC) to 4 units of fresh frozen plasma to 2 units of platelets. All TEP activations from February 1, 2006 to July 31, 2007 were retrospectively evaluated. A comparison cohort (pre-TEP) was selected from all trauma admissions between August 1, 2004 and January 31, 2006 that (1) underwent immediate surgery by the trauma team and (2) received greater than 10 units of PRBC in the first 24 hours. Multivariable analysis was performed to compare mortality and overall blood product consumption between the two groups. RESULTS: Two hundred eleven patients met inclusion criteria (117 pre-TEP, 94 TEP). Age, sex, and Injury Severity Score were similar between the groups, whereas physiologic severity (by weighted Revised Trauma Score) and predicted survival (by trauma-related Injury Severity Score, TRISS) were worse in the TEP group (p values of 0.037 and 0.028, respectively). After controlling for age, sex, mechanism of injury, TRISS and 24-hour blood product usage, there was a 74% reduction in the odds of mortality among patients in the TEP group (p = 0.001). Overall blood product consumption adjusted for age, sex, mechanism of injury, and TRISS was also significantly reduced in the TEP group (p = 0.015). CONCLUSIONS: We have demonstrated that an exsanguination protocol, delivered in an aggressive and predefined manner, significantly reduces the odds of mortality as well as overall blood product consumption.

Identification of the circadian transcriptome in adult mouse skeletal muscle.

Circadian rhythms are approximate 24-h behavioral and physiological cycles that function to prepare an organism for daily environmental changes. The basic clock mechanism is a network of transcriptional-translational feedback loops that drive rhythmic expression of genes over a 24-h period. The objectives of this study were to identify transcripts with a circadian pattern of expression in adult skeletal muscle and to determine the effect of the Clock mutation on gene expression. Expression profiling on muscle samples collected every 4 h for 48 h was performed. Using COSOPT, we identified a total of 215 transcripts as having a circadian pattern of expression. Real-time PCR results verified the circadian expression of the core clock genes, Bmal1, Per2, and Cry2. Annotation revealed cycling genes were involved in a range of biological processes including transcription, lipid metabolism, protein degradation, ion transport, and vesicular trafficking. The tissue specificity of the skeletal muscle circadian transcriptome was highlighted by the presence of known muscle-specific genes such as Myod1, Ucp3, Atrogin1 (Fbxo32), and Myh1 (myosin heavy chain IIX). Expression profiling was also performed on muscle from the Clock mutant mouse and sarcomeric genes such as actin and titin, and many mitochondrial genes were significantly downregulated in the muscle of Clock mutant mice. Defining the circadian transcriptome in adult skeletal muscle and identifying the significant alterations in gene expression that occur in muscle of the Clock mutant mouse provide the basis for understanding the role of circadian rhythms in the daily maintenance of skeletal muscle.

Prevention by granulocyte depletion of increased vascular permeability of sheep lung following endotoxemia.

To see whether circulating granulocytes are necessary for the lung vascular reaction to endotoxin, we measured the endotoxin response in chronically instrumented sheep before and after granulocyte depletion with hydroxyurea. Granulocyte depletion did not affect the pulmonary hypertension caused by endotoxin (peak mean pulmonary artery pressures = 38 +/- 2 cm H2O before depletion and 42 +/- 2 after depletion, P = NS). The late phase increase in lung lymph flow after endotoxin was significantly lower in the granulocytopenic animals as reflected by lung lymph flow (mean steady state lymph flow before depletion = 30.6 +/- 2.0 SE ml/h; mean steady state lymph flow after granulocyte depletion = 15.4 +/- 1.0; P less than 0.01) even though late phase pulmonary vascular pressures were similar before and after granulocyte depletion. Lung lymph protein clearance (lymph flow x lymph/plasma protein concentration) was also significantly lower after granulocyte depletion (mean steady state before depletion = 2.14 +/- 1.4 SE ml/h; and after depletion = 10.4 +/- 1.0; P less than 0.01). We conclude that circulating granulocytes are necessary for the development of increased lung vascular permeability to fluid and protein following endotoxin. The pulmonary vasopressor effects of endotoxin in sheep are independent of granulocytes.

In vivo assessment of pulmonary vascular integrity in experimental pulmonary edema.

During single pass indicator studies across the lungs [(14)C]urea remains in the vascular compartment, but its molecular size and solubility suggest it might escape abnormally permeable vessels. To test the hypothesis that [(14)C]urea might be used to distinguish pulmonary edema due to acutely increased intravascular pressure from that due to vascular damage by alloxan, we studied [(51)Cr]erythrocytes (r), [(125)I]albumin (a), [(14)C]urea (u), and tritiated water as dilution indicators in the pulmonary circulation of anesthetized dogs. In addition, the adequacy of albumin as an intravascular indicator was evaluated. Indicator curves, blood gases, hematocrit, and vascular pressures were determined during a base-line period and repeated 30 and 60 min after treatment in five groups of dogs: (a) saline control. (b) alloxan edema. (c) epinephrine infusion, (d) volume overload, and (e) left atrial (LA) balloon obstruction.Groups b, d, and e developed a similar degree of edema judging by wet/dry lung weights and histology. Groups a and c did not develop edema. In alloxan edema, differences between the mean transit time volume of u and r (V(v-r)) increased over base line at 30 (P < 0.001) and 60 min (P < 0.02); the differences between the mean transit time volume of a and r (V(e-r)) increased slightly at 30 (P < 0.03) and 60 min (P < 0.02); and V(u-r) significantly exceeded V(a-r) at 30 (mean difference = 9 ml, P < 0.02) and 60 min (mean difference = 11, P < 0.04). In none of the other groups did V(u-r) significantly exceed V(a-r). Thus, comparison of V(u-r) with V(a-r) may permit distinction between "high pressure" and "increased permeability" pulmonary edema. Albumin was not a consistently reliable indicator of intravascular volume as compared with composite red cell and albumin curve.

Methylprednisolone prevention of increased lung vascular permeability following endotoxemia in sheep.

To see whether methylprednisolone would affect the pulmonary vascular response to endotoxemia, we studied responses to endotoxemia in the presence and absence of methylprednisolone in the same chronically instrumented, unanesthetized sheep. Infusion of Escherichia coli endotoxin (0.70-1.33 mug/kg) caused an initial period of marked pulmonary hypertension followed several hours later by a long period of increased vascular permeability when pulmonary vascular pressures were near base line (base-line pulmonary artery pressure (PPa) = 21+/-1 cm H(2)O SE, left atrial pressure (Pla) = 1+/-3; experimental PPa = 20+/-3, Pla = 3+/-4; P = NS), lung lymph flow ( Qlym) was high (base-line Qlym = 7.2+/-0.2 ml/h; experimental Qlym = 23.2+/-1.0; P < 0.05) and lymph/plasma protein concentration (L/P) was high (base-line L/P = 0.65+/-0.04; experimental L/P = 0.79+/-0.05; P < 0.05). When methylprednisolone (1.0 g + 0.5 g/h i.v.) was begun 30 min before the same dose of endotoxin was infused, the initial pulmonary hypertension was less and the late phase increase in lung vascular permeability was prevented (experimental PPa = 24+/-1, Pla = 1+/-1, Qlym = 10.0+/-0.4; L/P = 0.56+/-0.03). Qlym and L/P were significantly (P < 0.05) lower than with endotoxin alone. Methylprednisolone began during the initial pulmonary hypertensive response to endotoxin also prevented the late phase increase in lung vascular permeability, but the drug had no effect once vascular permeability was increased. We conclude that large doses of methylprednisolone given before or soon after endotoxemia prevent the increase in lung vascular permeability that endotoxin causes, but do not reverse the abnormality once it occurs.

Effects of antihistamines on the lung vascular response to histamine in unanesthetized sheep. Diphenhydramine prevention of pulmonary edema and increased permeability.

To see whether antihistamines could prevent and reverse histamine-induced pulmonary edema and increased lung vascular permeability, we compared the effects of a 4-h intravenous infusion of 4 mug/kg per min histamine phosphate on pulmonary hemodynamics, lung lymph flow, lymph and plasma protein content, arterial blood gases, hematocrit, and lung water with the effects of an identical histamine infusion given during an infusion of diphenhydramine or metiamide on the same variables in unanesthetized sheep. Histamine caused lymph flow to increase from 6.0+/-0.5 to 27.0+/-5.5 (SEM) ml/h (P less than 0.05), lymph; plasma globulin concentration ratio to increase from 0.62+/-0.01 to 0.67+/-0.02 (P less than 0.05), left atrial pressure to fall from 1+/-1 to -3+/-1 cm H2O (P less than 0.05), and lung lymph clearance of eight protein fractions ranging from 36 to 96 A molecular radius to increase significantly. Histamine also caused increases in lung water, pulmonary vascular resistance, arterial PCO2, pH, and hematocrit, and decreases in cardiac output and arterial PO2. Diphenhydramine (3 mg/kg before histamine followed by 1.5 mg/kg per h intravenous infusion) completely prevented the histamine effect on hematocrit, lung lymph flow, lymph protein clearance, and lung water content, and reduced histamine effects on arterial blood gases and pH. 6 mg/kg diphenhydramine given at the peak histamine response caused lymph flow and lymph: plasma protein concentration ratios to fall. Metiamide (10 mg/kg per h) did not affect the histamine lymph response. We conclude that diphenhydramine can prevent histamine-induced pulmonary edema and can prevent and reverse increased lung vascular permeability caused by histamine, and that histamine effects on lung vascular permeability are H1 actions.

Effects of cyclooxygenase inhibitors on the alterations in lung mechanics caused by endotoxemia in the unanesthetized sheep.

The effects of Escherichia coli endotoxin on lung mechanics, hemodynamics, gas exchange, and lung fluid and solute exchange were studied in 12 chronically instrumented unanesthetized sheep. A possible role for cyclooxygenase products of arachidonate metabolism as mediators of the endotoxin-induced alterations in lung mechanics was investigated by studying sheep before and after cyclooxygenase inhibition with sodium meclofenamate and ibuprofen. Sheep were studied three times in random order: (a) sodium meclofenamate (or ibuprofen) infusion alone; (b) E. coli endotoxin alone; and (c) meclofenamate (or ibuprofen) and endotoxin. Meclofenamate alone had no effect on any of the variables measured. Endotoxin alone caused early marked changes in lung mechanics: resistance to airflow across the lungs (RL) increased 10-fold, dynamic lung compliance (Cdyn) decreased 80% and functional residual capacity (FRC) decreased by greater than 30%. The alveolar-to-arterial oxygen difference (delta AaPO2) increased markedly following endotoxemia. In the presence of sufficient meclofenamate to inhibit accumulation of thromboxane-B2 and 6-keto-prostaglandin F1 alpha in lung lymph, endotoxin caused no increase in RL, Cdyn decreased by less than 40%, and FRC decreased by only 6%. Meclofenamate significantly attenuated the hypoxemia and early pulmonary hypertension caused by endotoxemia but had no effect on the late increases in lung fluid and solute exchange. Ibuprofen had similar effects to those observed with meclofenamate. We conclude that both the pulmonary hypertension and changes in lung mechanics observed after endotoxemia may be mediated, at least in part, by constrictor prostaglandins or thromboxanes and that gas exchange may be improved by preventing endogenous synthesis of these mediators.

Effects of prostaglandin cyclic endoperoxides on the lung circulation of unanesthetized sheep.

Although prostaglandins E(2) and F(2alpha) have been suggested as mediators of the pulmonary hypertension seen after endotoxin infusion or during alveolar hypoxia, their precursors, the endoperoxides (prostaglandins G(2) and H(2)) are much more potent vasoconstrictors in vitro. In this study we compared the effects of prostaglandin (PG)H(2), a stable 9-methylene ether analogue of PGH(2) (PGH(2)-A), PGE(2), and PGF(2alpha) on pulmonary hemodynamics in awake sheep. The animals were prepared to allow for measurement of (a) lung lymph flow; (b) plasma and lymph protein concentration; (c) systemic and pulmonary vascular pressures; and (d) cardiac output. We also determined the effect of prolonged PGH(2)-A infusions on lung fluid balance and vascular permeability by indicator dilution methods, and by assessing the response of lung lymph. Both PGH(2) and PGH(2)-A caused a dose-related increase in pulmonary artery pressure: 0.25 mug/kg x min tripled pulmonary vascular resistance without substantially affecting systemic pressures. Both were 100 times more potent than PGE(2) or PGF(2alpha) in this preparation. PGH(2)-A, as our analysis of lung lymph and indicator dilution measurements show, does not increase the permeability of exchanging vessels in the lung to fluid and protein. It does, however, augment lung fluid transport by increasing hydrostatic pressure in the pulmonary circulation. We conclude: (a) that PGH(2) is likely to be an important mediator of pulmonary vasoconstriction; (b) its effects are probably not a result of its metabolites PGE(2) or PGF(2alpha).

Increased sheep lung vascular permeability caused by pseudomonas bacteremia.

In awake sheep, we compared the responses of lung lymph flow and lymph and plasma protein concentrations to steady state elevations of pulmonary vascular pressures made by inflating a left atrial balloon with those after an intravenous infusion of 10(5)-10(10)Pseudomonas aeruginosa. Lymph flow increased when pressure was increased, but lymph-plasma protein concentration ratios always fell and lymph protein flow (lymph flow x lymph protein concentration) increased only slightly. After Pseudomonas, sheep had transient chills, fever, leukopenia, hypoxemia, increased pulmonary artery pressure and lymph flow and decreased left atrial pressure and lymph protein concentration, 3-5 h after Pseudomonas, when vascular pressures and lymph protein concentrations had returned to near base line, lymph flow increased further to 3-10 times base line and remained at a steady level for many hours. During this steady state period, lymph-plasma protein concentration ratios were similar to base line and lymph protein flow was higher than in the increased pressure studies. Two sheep died of pulmonary edema 7 and 9 h after Pseudomonas, but in 16 studies, five other sheep appeared well during the period of highest lymph flow and all variables returned to base line in 24-72 h. Six serial indicator dilution lung water studies in five sheep changed insignificantly from base line after Pseudomonas. Postmortem lung water was high in the two sheep dead of pulmonary edema and one other, but six sheep killed 1-6 h after Pseudomonas had normal lung water. Because of the clear difference between the effects of increased pressure and Pseudomonas on lymphplasma protein concentration ratios and lymph protein flow, we conclude that Pseudomonas causes a prolonged increase in lung vessel permeability to protein. Because we saw lung lymph flow as high as 10 times base line without pulmonary edema, we conclude that lung lymphatics are a sensitive high-capacity mechanism for removing excess filtered fluid. An equivalent pore model of sheep lung vessels suggests that the changes we saw after Pseudomonas could result from small changes in the structure of exchanging vessel walls.