摘要:

ObjectiveTo explore the role of the horizontal orientation of endotracheal tube and neck on bacterial colonization of the respiratory tract in anesthetized sheep on mechanical ventilation, without use of antibiotics.DesignProspective animal study.SettingNational Institutes of Health research laboratory.SubjectsAnesthetized, paralyzed, and ventilated sheep.InterventionsSheep were randomized into five groups and managed as follows: Group IS contained sheep that were not intubated and were immediately killed. Group HU4 contained six sheep that were mechanically ventilated for 4 hrs, with head and endotracheal tube elevated 30 degrees from horizontal. Group HU72 contained seven sheep that were prone, mechanically ventilated for 72 hrs, and managed the same as group HU4. Groups G and Gf each contained seven sheep that were prone on a lateral body rotation device, mechanically ventilated for 72 hrs, with neck and endotracheal tube horizontal. Group Gf received nasogastric enteral feeding.Measurements and Main ResultsAt the end of the study, sheep were examined postmortem, and a total of 11 tissue samples were taken from the trachea, the five lobar bronchi, and the five lobar parenchyma, for qualitative and quantitative culture. Group HU72 had significant decrease in Pao2/Fio2and heavy bacterial colonization in all sheep. Groups G and Gf retained excellent lung function; lung bacterial colonization was no different from the IS group.ConclusionsThe horizontal orientation of the endotracheal tube and neck, through lateral body rotation, showed no altered airway colonization and maintained excellent gas exchange and lung function in our animal model.

ISSN:0090-3493    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

ObjectiveTo investigate whether the response to sustained inflation and postinflation positive end-expiratory pressure varies between acute respiratory distress syndrome with pulmonary (ARDSp) and extrapulmonary origin (ARDSexp).DesignProspective clinical study.SettingMultidisciplinary intensive care unit in a university hospital.PatientsA total of 11 patients with ARDSpand 13 patients with ARDSexp.InterventionsA 7 ml/kg tidal volume, 12–15 breaths/min respiratory rate, and an inspiratory/expiratory ratio of 1:2 was used during baseline ventilation. Positive end-expiratory pressure levels were set according to the decision of the primary physician. Sustained inflation was performed by 45 cm H2O continuous positive airway pressure for 30 secs. Postinflation positive end-expiratory pressure was titrated decrementally, starting from a level of 20 cm H2O to keep the peripheral oxygen saturation between 92% and 95%. Fio2was decreased, and baseline tidal volume, respiratory rate, inspiratory/expiratory ratio were maintained unchanged throughout the study period.Measurements and Main ResultsBlood gas, airway pressure, and hemodynamic measurements were performed at the following time points: at baseline and at 15 mins, 1 hr, 4 hrs, and 6 hrs after sustained inflation. After sustained inflation, the Pao2/Fio2ratio improved in all of the patients both in ARDSpand ARDSexp. However, the Pao2/Fio2ratio increased to >200 in four ARDSppatients (36%) and in seven ARDSexppatients (54%). In two of those ARDSppatients, the Pao2/Fio2ratio was found to be <200, whereas none of the ARDSexppatients revealed Pao2/Fio2ratios of <200 at the 6-hr measurement. Postinflation positive end-expiratory pressure levels were set at 16.7 ± 2.3 cm H2O in ARDSexpand 15.6 ± 2.5 cm H2O in ARDSp. The change in Pao2/Fio2ratios was found statistically significant in patients with ARDSexp(p= .0001) and with ARDSp(p= .008). Respiratory system compliance increased in ARDSexppatients (p= .02), whereas the change in ARDSpwas not statistically significant.ConclusionsSustained inflation followed by high levels of postinflation positive end-expiratory pressure provided an increase in respiratory system compliance in ARDSexp; however, arterial oxygenation improved in both ARDS forms.

ISSN:0090-3493    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

ObjectiveBy constraining the heart, the chest wall, lungs, and pericardium limit diastolic filling and thus have a major role in determining cardiac output. Although intermittent positive pressure ventilation and the application of positive end-expiratory pressure amplifies this constraint, no clinical method exists to assess the impact that positive end-expiratory pressure has on ventricular constraint in the newborn. In this study, we tested the hypothesis that a change in right atrial pressure (Pra) reflects the change in ventricular constraint associated with a change in airway pressure.DesignExperimental, comparative animal study.SettingRitchie Centre for Baby Health Research cardiovascular laboratory.SubjectsNeonatal (4-wk-old, n = 6) and newborn (3-day-old, n = 6) Merino/Border-Leicester cross lambs.InterventionsLambs were anesthetized (&agr;-chloralose and ketamine), ventilated, and instrumented to record Pra, thoracic inferior vena caval pressure (Pivc, saline-filled catheters), and pericardial pressure (Pper, liquid-containing balloon).Measurements and Main ResultsChanges (&Dgr;) in Pra, Pivc, and Pper were assessed while airway pressure was rapidly reduced from four set levels of continuous positive airway pressure (2.5, 5, 7.5, and 15 cm H2O) to atmospheric pressure. A strong linear relationship was observed between &Dgr;Pra and &Dgr;Pper (&Dgr;Pra = 0.90 &Dgr;Pper − 0.02,r2= .98), and between &Dgr;Pivc and &Dgr;Pper (&Dgr;Pivc = 0.86 &Dgr;Pper − 0.02,r2= .98) in both the 4-wk-old lambs and the 3-day-old lambs.ConclusionsOur experiments demonstrate that, in the newborn and neonatal lamb, &Dgr;Pra provides an accurate measure of the change in ventricular constraint that accompanies a change in airway pressure, and thus may provide a means of quantifying the magnitude of ventricular constraint imposed by positive end-expiratory pressure and mechanical ventilation during neonatal intensive care.

ISSN:0090-3493    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

ObjectiveTo generate and validate a predictive score of yeast isolation based on independent risk factors of yeast isolation in intensive care unit patients with peritonitis.DesignRetrospective cohort study to determine independent risk factors of yeast isolation, generation of the score, and validation in a prospective cohort of patients with peritonitis.SettingTertiary-care, university-affiliated hospital.PatientsTwo hundred twenty-one patients with peritonitis hospitalized in a surgical intensive care unit between 1994 and 1999 for the retrospective cohort and 57 patients in the prospective cohort (2000).Measurements and Main ResultsFour independent risk factors of yeast isolation in peritoneal fluid (similar odds ratio) were found in the retrospective cohort: female gender, upper gastrointestinal tract origin of peritonitis, intraoperative cardiovascular failure, and previous antimicrobial therapy at least 48 hrs before the onset of peritonitis. A score based on the number of risk factors was constructed (grade A = zero or one risk factor, grade B = at least two risk factors, grade C = at least three risk factors, and grade D = four risk factors), and validated in the prospective cohort. For a grade C score, sensitivity was 84%, specificity was 50%, positive and negative predictive values were 67% and 72%, respectively, and overall accuracy was 71%.ConclusionsFour independent risk factors of yeast isolation in the peritoneal fluid were identified in critically ill surgical patients with peritonitis. The presence of at least three of these factors (grade C score) was associated with a high rate of yeast detection. This approach could be helpful to initiate early antifungal therapy in this patient population.

ISSN:0090-3493    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

ObjectiveMechanical circulatory support can maintain vital organ perfusion in patients with cardiac failure unresponsive to standard pharmacologic treatment. The purpose of the current study was to report complication and survival rates in patients supported with emergency percutaneous venoarterial cardiopulmonary bypass because of prolonged cardiogenic shock or cardiopulmonary arrest.DesignRetrospective clinical study.SubjectsA total of 46 patients supported with venoarterial cardiopulmonary bypass, 25 because of cardiogenic shock unresponsive to pharmacologic therapy and 21 because of cardiopulmonary arrest unresponsive to standard advanced cardiac life support.ResultsIn 41 of the 46 patients (89%), stable extracorporeal circulation was established; in five patients (11%), femoral cannulation was accomplished only after a surgical cutdown. A total of 28 patients were weaned from cardiopulmonary bypass (19 of 25 patients with cardiogenic shock vs. 9 of 21 patients with cardiopulmonary arrest,p= .03), and 13 patients had long-term survival (10 of 25 patients with cardiogenic shock vs. 3 of 21 patients with cardiopulmonary arrest,p= .1). Complications directly related to the use of cardiopulmonary bypass were found in 18 patients (39%), major complications related to femoral cannulation being the most common single cause for bypass-associated morbidity (eight patients, 17%)ConclusionsLong-term survival rates after emergency percutaneous cardiopulmonary bypass are encouraging in patients with an underlying cardiocirculatory disease amenable to immediate corrective intervention (angioplasty, surgery, transplantation).

ISSN:0090-3493    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

ContextIn recent years, protective ventilation with airway pressure limitation has constituted a major advance in acute respiratory distress syndrome treatment and has led to a substantial improvement in prognosis. With this therapeutic rationale, one may even question nowadays whether the severity of respiratory failureper sestill influences mortality.ObjectiveTo determine whether the severity of respiratory failure, scored according to the usual criteria, still influences mortality in acute respiratory distress syndrome patients when a low stretch ventilation was used and to assess the impact on mortality of other nonpulmonary organ dysfunction, particularly circulatory failure.Design and SettingA retrospective study conducted in the medical intensive care unit of a French university hospital from October 1993 to December 2001.PatientsA total of 150 acute respiratory distress syndrome patients who were administered uniform protective ventilation with a limited plateau pressure (<30 cm H2O), a low positive end-expiratory pressure (<10 cm H2O), and the same strategy concerning hemodynamic support and dialysis when required.Main Outcome and MeasuresMean age, general severity index (Simplified Acute Physiologic Score II), number of associated organ failures (Logistic Organ Dysfunction Score), respiratory severity indices (Pao2/Fio2, Lung Injury Severity Score), and severity of initial circulatory failure (circulatory failure present at admission or that developed during the first 48 hrs) were compared, according to recovery or death, and evaluated by a logistic regression model, which allows simultaneous control of multiple factors.ResultsThe average mortality rate for the whole group was 38%, with 93 patients recovering after an average duration of mechanical ventilation of 18 ± 13 days. The major factor significantly and independently associated with probability of dying was the severity of circulatory failure (p= .0001, odds ratio = 10.17). Patients free from initial circulatory failure (39 patients) had a 95% recovery rate.ConclusionWith our low stretch strategy, the severity of circulatory failure was the main determinant of acute respiratory distress syndrome prognosis. Patients with isolated respiratory failure during the first 48 hrs of respiratory support have an excellent chance of recovery when treated with protective ventilation associated with a low positive end-expiratory pressure.

ISSN:0090-3493    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

ObjectivePlatelet-activating factor (PAF) is a proinflammatory phospholipid that may contribute to inflammation in the acute respiratory distress syndrome (ARDS). PAF acetylhydrolase (PAF-AH) degrades PAF and regulates its biological activity. We characterized PAF-AH in bronchoalveolar lavage fluid from ARDS patients (n = 33, 22 survivors), patients at risk for ARDS (n = 6), and healthy controls (n = 6).DesignBronchoalveolar lavage was performed during acute (<96 hrs from onset), plateau (6 to 12 days), and late (≥14 days) phases of ARDS.PatientsIntubated patients with ARDS or a risk factor for ARDS.Measurements and Main ResultsIn ARDS, total bronchoalveolar lavage PAF-AH activity was markedly increased in the acute phase (87 ± 89 mU/mL, n = 33) and then decreased in the plateau (23 ± 14 mU/mL, n = 10) and late phases (19 ± 14 mU/mL, n = 7) (p= .003). Total bronchoalveolar lavage PAF-AH activity during the acute phase of ARDS was also increased as compared with patients at risk for ARDS (16 ± 13 mU/mL, n = 6) and healthy controls (3 ± 3 mU/mL, n = 6) (p< .001). In contrast, plasma PAF-AH activities were the same in controls (3215 ± 858 mU/mL, n = 6), in patients at risk for ARDS (3606 ± 1607 mU/mL, n = 6), and during the acute phase of ARDS (3098 ± 2395 mU/mL, n = 33) (p= .18). PAF-AH mRNA was present in alveolar macrophages in the acute phase of ARDS (five of six) and in at-risk patients (two of three) but not in healthy controls.ConclusionsPAF-AH activity is increased in bronchoalveolar lavage fluid from patients with ARDS. Likely sources include leakage of plasma PAF-AH into alveoli or release of PAF-AH from injured cells; however, the presence of PAF-AH mRNA in alveolar macrophages suggests that PAF-AH may be actively synthesized in the lungs of patients with ARDS. PAF-AH activity in the lungs of ARDS patients may regulate inflammation caused by PAF and related oxidized phospholipids generated in the inflammatory response.

ISSN:0090-3493    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

ObjectiveOpioid analgesia impairs gastrointestinal motility. Enteral administration of naloxone theoretically allows selective blocking of intestinal opioid receptors caused by extensive presystemic metabolism. Therefore, we studied the effect of enteral naloxone on the amount of gastric tube reflux, the frequency of pneumonia, and the time until first defecation in mechanically ventilated patients with fentanyl analgesia.DesignProspective, randomized, double-blinded study.SettingUniversity hospital intensive care unit.PatientsEighty-four mechanically ventilated, fentanyl-treated patients without gastrointestinal surgery or diseases.InterventionsPatients were assigned to receive 8 mg naloxone or placebo four times daily via a gastric tube during fentanyl administration.Measurements and Main ResultsThirty-eight patients received naloxone and 43 placebo; three patients were excluded because of protocol violation. Median gastric tube reflux volume (54 vs. 129 mL,p= .03) and frequency of pneumonia (34% vs. 56%,p= .04) were significantly lower in the naloxone group. In both groups, time until first defecation, ventilation time, and length of intensive care unit stay did not differ. There was no difference in fentanyl requirements between the naloxone and the placebo group (7 vs. 6.5 &mgr;g/kg/hr,p= .15).ConclusionsOur results provide evidence that the administration of enteral opioid antagonists in ventilated patients with opioid analgesia might be a simple—and possibly preventive—treatment of increased gastric tube reflux and reduces frequency of pneumonia.

ISSN:0090-3493    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

ObjectiveTo investigate salivary flow and frequency of oral mucositis in intensive care unit patients compared with patients admitted because of elective coronary artery bypass graft (CABG) surgery. In addition, the pattern of oropharyngeal colonization was investigated in these patients.DesignProspective study.SettingMixed intensive care unit and cardiosurgical ward.PatientsIn this study, 24 ventilated intensive care unit patients and 20 CABG patients were included.Measurements and Main ResultsTwo dental hygienists examined intensive care unit patients for the presence of periodontal disease and mucositis at admission and subsequently every week during their stay in the intensive care unit. At the same time, stimulated salivary flow and salivary total immunoglobulin A output were measured. Oropharyngeal cultures were obtained as well. CABG patients were examined the day before the operation, 1 day, 1 wk, and 2 wks after the operation. The following results were obtained: a) temporarily reduced postoperative stimulated salivary flow and total salivary immunoglobulin A output in CABG patients and nearly absent stimulated salivary flow in intensive care unit patients; b) oropharyngeal colonization with potentially pathogenic microorganisms in intensive care unit and not in CABG patients; and c) the increase in mucositis index in intensive care unit patients paralleled the increase in potentially pathogenic microorganism oropharyngeal colonization, especiallyEnterobacteriaceaeandPseudomonas aeruginosa.ConclusionsAbsence of adequate salivary flow in intubated intensive care unit patients causes severe xerostomia, which may contribute to the development of mucositis and oropharyngeal colonization with Gram-negative bacteria.

ISSN:0090-3493    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

ObjectivesSome propofol emulsion formulations contain EDTA or sodium metabisulfite to inhibit microbe growth on extrinsic contamination. EDTA is not known to react with propofol formulation components; however, sulfite has been shown to support some oxidation processes and may react with propofol. This study compared the oxidation of propofol and the formation of free radicals by electron paramagnetic resonance analysis in EDTA and sulfite propofol emulsions during a simulated intensive care unit 12-hr intravenous infusion.DesignControlled laboratory study.SettingUniversity laboratory.Measurements and Main ResultsPropofol emulsions (3.5 mL) were dripped from spiked 50-mL vials at each hour for 12 hrs. Two propofol oxidation products, identified as propofol dimer and propofol dimer quinone, were detected in sulfite and EDTA propofol emulsions; however, sulfite propofol emulsion contained higher quantities of both compounds. After initiation of the simulated infusion, the quantities of propofol dimer and propofol dimer quinone increased in the sulfite propofol emulsion, but the lower levels in the EDTA propofol emulsion remained constant. Sulfite propofol emulsion began to visibly yellow at about 6–7 hrs. The EDTA propofol emulsion remained white at all times. The absorbance spectra of the propofol dimer and propofol dimer quinone extracted from sulfite propofol emulsion showed that propofol dimer did not absorb in the visible spectrum, but the propofol dimer quinone had an absorbance peak at 421 nm, causing it to appear yellow. Electron paramagnetic resonance analysis of the propofol emulsion containing metabisulfite revealed that the sulfite propofol emulsion yielded a strong free radical signal consistent with the formation of the sulfite anion radical (SO3·−). The EDTA propofol emulsion yielded no free radical signal above background.ConclusionSulfite from the metabisulfite additive in propofol emulsion creates an oxidative environment when these emulsions are exposed to air during a simulated intravenous infusion. This oxidation results in propofol dimerization and emulsion yellowing, the latter of which is caused by the formation of propofol dimer quinone. These processes can be attributed to the rapid formation of the reactive sulfite free radical.

ISSN:0090-3493    

出版商:OVID    

年代:2003

数据来源: OVID