摘要:

ObjectivesSepsis is one of the most important predisposing factors for the development of the acute respiratory distress syndrome (ARDS). Alterations of pulmonary surfactant contribute in the pathogenesis of ARDS. However, little is known about surfactant in patients with less severe grades of lung injury related to sepsis or systemic inflammatory response syndrome (SIRS). Therefore, the purpose of this study was to characterize endogenous surfactant in surgical intensive care patients with sepsis or SIRS.DesignProspective, observational study.SettingUniversity-affiliated, interdisciplinary intensive care unit.PatientsEleven patients after major surgery with SIRS or sepsis included within 12 hrs of onset and 11 controls without infection or lung disease.InterventionsOperating room and standard intensive care unit management.Measurements and Main ResultsFour serial bronchoalveolar lavage samples (BAL) were recovered over 7 days from the patients and single BAL samples were obtained from controls. BAL cells, total protein, surfactant-associated protein A (SP-A), surfactant alveolar transition forms, and surface activity were analyzed. Two of 11 patients met criteria for acute lung injury and six of the 11 patients met ARDS consensus conference criteria but acute lung injury or ARDS was not persistent. The mean PaO2/FIO2for the patients over 7 days was 253.2 +/- 15.1 (SEM) and Murray's lung injury score was 1.12 +/- 0.12, indicating mild-to-moderate lung injury. BAL neutrophil counts were increased (p < .01), and the ratio of poorly functioning light aggregate surfactant to superiorly functioning heavy aggregate surfactant was increased compared with controls (0.32 +/- 0.06 vs. 0.09 +/- 0.01, p < .05). SP-A was decreased (1.9 +/- 0.4 vs. 3.5 +/- 0.6 [micro sign]g/mL of BAL, p < .05) and there were increases in the ratios of phospholipid to SP-A (p < .05), protein to SP-A (p < .01), and protein to phospholipid (p < .05). The surface tension-lowering ability of purified heavy aggregate surfactant was significantly impaired (15.6 +/- 1.6 vs. 2.8 +/- 0.6 milliNewtons/m, p < .05).ConclusionsThese observations show that surgical patients with SIRS or sepsis who have mild-to-moderate lung injury develop surfactant dysfunction detectable within 7 days of onset. We propose, therefore, that therapeutic strategies to modulate these severe surfactant abnormalities should be considered, as these strategies may have the potential to reduce lung injury, which is associated with a high mortality in sepsis. (Crit Care Med 1999; 27:82-89)

ISSN:0090-3493    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

ObjectiveTo examine and compare the effects of omeprazole, lansoprazole, and ranitidine on the DNA synthesis of peripheral blood mononuclear cells.DesignEx vivo laboratory study.SettingClinical research laboratory of an academic medical center.SubjectsHealthy volunteers.InterventionsNone.Measurements and Main ResultsVenous blood was collected from normal subjects and peripheral blood mononuclear cells (PBMCs) were isolated using centrifugation techniques over a Ficoll-Hypaque density gradient. PBMCs were added to 12-well culture plates in four groups of media: a) control; b) control plus lansoprazole (25 [micro sign]g/mL); c) control plus omeprazole (0.35 [micro sign]g/mL); and d) control plus ranitidine (50 [micro sign]g/mL). PBMCs were exposed to the drug for 96 hrs, with addition of phytohemagglutinin (2.5 [micro sign]g/mL) for the last 48 hrs, and3H-thymidine (1 [micro sign]Ci) during the final 6 hrs. PBMCs were filtered onto glass-fiber filter paper and the radio-activity was determined by scintillation counting. Since radioactivity is measured only in those cells undergoing DNA synthesis or cell division, results are expressed as quantification of3H-thymidine uptake. Median disintegrations per min (DPM)/number of PBMCs per well +/- SEM are reported: control 68.3 +/- 37.8; ranitidine 38.4 +/- 94.2; lansoprazole 14.6 +/- 84.4; and omeprazole 15.1 +/- 48.9. There was a significant difference between lansoprazole vs. ranitidine (p < .01), and omeprazole vs. ranitidine (p < .05), and no significant difference between lansoprazole and omeprazole.ConclusionsThis is the first study to compare the potential immunomodulating effects of these commonly used agents. Ranitidine caused increased DNA synthesis in PBMCs when compared with lansoprazole and omeprazole. This phenomenon may be an important, often disregarded, effect of histamine-2-receptor antagonists when used in postsurgical or trauma patients who have T-lymphocyte-mediated immune suppression. (Crit Care Med 1999; 27:90-94)

ISSN:0090-3493    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

ObjectiveTo delineate the frequency and causes of admission to a critical care environment for patients undergoing head and neck surgery at Memorial Sloan-Kettering Cancer Center.DesignRetrospective clinical investigation.SettingAdult intensive care unit of a tertiary referral cancer center.PatientsAll head and neck surgery patients admitted to the special care unit (SCU) of Memorial Sloan-Kettering Cancer Center between January 1, 1994 and December 31, 1995 were included in this study.InterventionsNone.Measurements and Main ResultsThe data collected included demographic, operative procedures, clinical, laboratory, and physiologic variables at time of SCU admission, at 24 hrs, as well as vital status at the time of discharge from the SCU and hospital. Other data collected were the need for mechanical ventilation and inotropic agents. During the period of January 1, 1994 through December 31, 1995, 37 (1.5%) of 2,346 patients undergoing head and neck surgical procedures required admission to the SCU. During the same period, six patients receiving medical treatment only for head and neck malignant disease were transferred to the SCU. These 43 admissions served as the basis for the study. The causes of admission to the SCU were pulmonary (15/43), cardiac (14/43), wound related (8/43), and other (15/43). The median length of stay in the SCU was 2 days, and the median hospitalization for patients requiring critical care services was 22 days. Seventy-four percent of patients requiring critical care services were eventually discharged to home.ConclusionsCurrent preoperative evaluation, operative and anesthetic techniques, and perioperative care result in a low frequency of utilization of critical care services by patients undergoing head and neck surgery. There is no single identifiable cause of complications for patients after head and neck surgery leading to utilization of critical care services. (Crit Care Med 1999; 27: 95-97)

ISSN:0090-3493    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

ObjectiveTo determine the rationale for using stress ulcer prophylaxis (SUP) among clinicians; to assess criteria used to define failure of SUP; and to evaluate the decision-making process in the selection of a prophylactic agent.DesignA cross-sectional national mail survey.SettingRandom sample of the members of the Society of Critical Care Medicine who identified anesthesiology, surgery, or internal medicine as their primary specialty area.PatientsNone.InterventionNone.Measurements and Main ResultsQuestionnaires consisting of multiple-choice and short-answer questions were sent to a simple random sample of 1,268 physicians to assess the current practice of SUP. A total of 328 usable questions were returned, resulting in a response rate of 26%. All percentages reported in the results are based on the total number of responses. The risk factors for SUP that were most commonly identified were burns (91%), shock (90%), and sepsis (88%). These were also risk factors for which the respondents most commonly started SUP. Histamine-2-receptor (H2)-antagonists as a class, were the most commonly used prophylactic agents (67%). The most commonly used agents for SUP were ranitidine (31%), famotidine (24%), sucralfate (24%), and cimetidine (12%). Most respondents selected ranitidine for ease of administration, famotidine because of formulary availability, sucralfate for a better side effects profile, and cimetidine for cost-effectiveness. Eighty-two percent of respondents considered the presence of bright red blood in the nasogastric tube as failure of SUP. In cases where SUP failed, most respondents would add a second agent from a different therapeutic class. Of those respondents who used an H2-antagonistinitially, 48% would add sucralfate, 36% would add antacid, and 13% would add omeprazole. Of those respondents who used sucralfate, 77% would add an H2-antagonistwhen SUP failed. For those respondents who would switch to another agent when the H2-antagonistfailed, 52% would change to omeprazole, whereas 67% would change to an H2-antagonistwhen sucralfate failed. Only eight respondents would discontinue SUP when risk factors were resolved. Most respondents would discontinue SUP when the patient was no longer in the "nothing by mouth" status (28%), started on enteral feeding (23%), or discharged from the intensive care unit (21%). The mean duration of SUP was 6.3 +/- 4.5 (SD) days.ConclusionsThis survey highlighted the lack of consensus in the use of SUP. Many patients receive SUP for an extended period, without clear-cut indications or documented benefit. The cost of unwarranted SUP in patients with low risk of stress ulcer gastrointestinal bleeding is prohibitive. Treatment algorithms or protocols for SUP based on prescribing patterns, hospital formulary restrictions, and cost-analysis should be considered for each institution to guide critical care physicians on the proper use of SUP therapies. (Crit Care Med 1999; 27:98-103)

ISSN:0090-3493    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

ObjectiveTo evaluate whether changes have occurred at our center in the rate of nosocomial infections and in the infectious organisms consequent to changes in policy and procedure as of 1987.SettingMultidisciplinary pediatric intensive care unit (PICU) in a major tertiary care center.DesignProspective comparative study.PatientsFour-hundred and fifty-five consecutive patients who underwent cardiac surgery within a 10-month period.InterventionsChanges related to antibiotic use and invasive device management were introduced after the 1987 survey. To determine the effect of these changes, all patients undergoing cardiac surgery between July 1991 and April 1992 were followed daily from PICU admission to 2 months after hospital discharge for signs of infection. Each infectious episode was reviewed by the nosocomial infection control committee. A weighted scoring system was used to determine risk.Measurements and Main ResultsIn the 1987 study, 40 of 310 patients had 78 infections for a nosocomial infection ratio (NIR) of 25.2. Of the 455 patients surveyed in 1992, 72 had 91 episodes of infection. The nosocomially infected patient rate was 15.8 and the NIR was 20. The frequency of wound infection decreased from 7% in 1987 to 4.3% in this study, and no episode of mediastinitis was observed. In the bacteriological spectrum, the absence of candidal infection was significant, and there was a decrease in the proportional frequency of pseudomonas infection from 21% to 15%.ConclusionThe comparison between the two time periods demonstrates that an aggressive approach to managing intravascular catheters and urinary catheters and limiting the use of antibiotics probably affects the spectrum of nosocomial infections. (Crit Care Med 1999; 27:104-108)

ISSN:0090-3493    

出版商:OVID    

年代:1999

数据来源: OVID

ISSN:0090-3493    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

ObjectivesTo demonstrate improved ventilation with intratracheal pulmonary ventilation (ITPV) in newborn lambs with congenital diaphragmatic hernia, using a new microprocessor controlled ITPV-specific ventilator.DesignProspective study, with each animal serving as its own control (paired data).SettingLarge animal research laboratory.SubjectsDiaphragmatic hernias were created surgically in seven fetal sheep on gestational day 100 (term = 145 days).InterventionsLambs (2.7 to 5.0 kg) were delivered by cesarean section anywhere between gestational days 136 and 140. Arterial and venous catheterizations, bilateral chest tube thoracostomies, and tracheostomies were performed while the lambs received placental bypass. Initially, congenital diaphragmatic hernia lambs were supported on conventional pressure control mechanical ventilation to achieve steady state with measurements of baseline vital signs, arterial blood gases, and ventilatory settings. ITPV was instituted while maintaining constant peak carinal pressures and oxygen saturations. Statistical comparisons were made using the paired t-test.Measurements and Main ResultsPostductal PaCO2decreased from 110 +/- 21 (SD) torr (14.7 +/- 2.8 kPa) to 52 +/- 24 torr (6.93 +/- 3.2 kPa; p = .0014) on ITPV. Simultaneously, pH improved from 7.04 +/- 0.07 to 7.31 +/- 0.15 (p = .0012) and minute ventilation increased from 0.66 +/- 0.40 to 4.00 +/- 1.35 L/min (p = .0016). Peak carinal pressures and postductal PaO2were unchanged.ConclusionsITPV significantly improved CO2removal in newborn lambs with diaphragmatic hernias without increasing airway pressures or changing oxygenation. Based on these results, we are conducting human clinical trials. (Crit Care Med 1999; 27: 109-112)

ISSN:0090-3493    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

ObjectiveSeptic animals receiving high-protein liquid diets have increased mortality and increased production of cytokines by the gut compared with animals receiving low-protein diets. The purpose of this study was to evaluate the ability of pentoxifylline to alter gut cytokine production in a rat model of prolonged acute peritonitis, to determine its effect on survival in such animals, and to determine whether alteration of gut cytokine production was associated with survival.DesignProspective, randomized animal study.SettingResearch laboratory.SubjectsMale Lewis rats weighing between 250 and 300 g.InterventionsAnesthetized rats had placement of a gastrostomy, followed 1 wk later by implantation of a bacteria-filled osmotic minipump into the peritoneal cavity. Rats were fed a high-protein (20% total energy) enteral diet. Saline or pentoxifylline (5 or 20 mg/kg im) was administered daily beginning at the time of pump implantation.Measurements and Main ResultsSeptic rats fed the high-protein liquid diet and given pentoxifylline in a dose of 5 mg/kg/day demonstrated improved survival compared with saline-treated animals or animals given the high dose (20 mg/kg/day) of pentoxifylline (p < .05). Administration of pentoxifylline at 5 mg/kg/day also down regulated the production of IL-6 messenger RNA (mRNA) in liver and lipopolysaccharide binding protein mRNA in the liver and intestine of septic animals given the high-protein liquid diet.ConclusionLow-dose (but not high-dose) pentoxifylline administration reduced production of some, but not all, cytokines studied in the gut and liver in a rat model of acute peritonitis and this reduced production was associated with an improved survival in such animals. (Crit Care Med 1999;27:113-119)

ISSN:0090-3493    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

ObjectiveChanges in pulmonary blood flow rate can alter the size of the perfused pulmonary capillary surface area. We tested the hypothesis that full recruitment of the pulmonary vascular bed may decrease evidence of lung injury by recruiting less injured capillaries. We also tested the hypothesis that endothelial ectoenzyme activity is an earlier indicator of lung injury than are permeability measures.DesignIsolated canine lung lobes were perfused with autologous blood at constant blood flows of either 2.05 +/- 0.04 L/min (SEM) (high flow, full recruitment, n = 12) or 0.600 +/- 0.004 L/min (low flow, 33% full recruitment, n = 12) after lung injury to determine the effect of vascular recruitment on measures of injury.SettingResearch laboratory at a medical university.SubjectsLung lobes were obtained from 36 mongrel dogs of either gender.InterventionsLung injury was induced by adding phorbol myristate acetate (PMA) to the blood perfusing the isolated lung.Measurements and Main ResultsIndicator dilution methods were used to measure single pass hydrolysis of3[H]-benzoyl-Phe-Ala-Pro, a synthetic substrate for angiotensin converting enzyme, and calculate the modified first order kinetic parameter corresponding to the ratio of a normalized maximal enzymatic conversion rate (Amax) to the Michaelis-Menten constant (Km), i.e., Amax/Km, before and after PMA. At a given flow rate, the decrease in Amax/Kmserves as an index of vascular injury. PMA decreased Amax/Km, percent metabolism, and fractional substrate utilization, and increased permeability, vascular resistance, and vascular pressures regardless of flow rate. The decrease in enzyme activity was detected earlier than the increase in permeability.ConclusionsThe greater percentage decrease in percent metabolism and fractional substrate utilization and the earlier appearance of increased permeability during high flow indicates that increasing blood flow three-fold recruited injured vessels and/or increased vascular injury by increasing vascular perfusion pressures. (Crit Care Med 1999; 27:120-129)

ISSN:0090-3493    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

ObjectiveTo analyze and compare the capillary permeability-reducing effects of prostacyclin, terbutaline, and aminophylline.DesignA prospective, experimental study.SettingA university laboratory.SubjectsFourteen adult, anesthetized cats.InterventionsThe study was performed on an autoperfused calf muscle preparation enclosed in a plethysmograph, with continuous recordings of tissue volume, arterial and venous blood pressures, and blood flow. The capillary filtration coefficient was used as a measure of capillary hydraulic permeability, and measured at different doses of intravenous infusions of prostacyclin, terbutaline, and aminophylline. These analyses were made from normal and from raised permeability levels, the latter by prior and simultaneous infusion of tumor necrosis factor-alpha (TNF-alpha) or histamine. All three of the drugs analyzed were given at low doses, without vasodilator effect, and at doses with a clear vasodilator effect.Main ResultsProstacyclin infusion reduced capillary permeability to a value of about 25% below the initial control value, and this level was reached both from normal and increased permeability levels. The maximal reduction level was obtained at a low nonvasodilator dose of 2 ng/kg/min. Terbutaline and aminophylline had no significant effect on capillary filtration coefficient when tested from the initial control permeability level. From a TNF-alpha-raised permeability level (about 50% above control) and from a histamine-raised permeability level (about 60% above control), both drugs induced small reductions in the capillary filtration coefficient.ConclusionLow-dose prostacyclin effectively reduces hydraulic capillary permeability in cat skeletal muscle and is superior to terbutaline and aminophylline. (Crit Care Med 1999; 27:130-136)

ISSN:0090-3493    

出版商:OVID    

年代:1999

数据来源: OVID