摘要:

Objective:To evaluate the feasibility of a closed-loop system for simultaneous control of systemic arterial and pulmonary artery blood pressures during cardiac surgery.Design:Feasibility study.Setting:The cardiac surgery operating room.Patients:The performance of the multiple-drug closed-loop system was evaluated during cardiac surgery in 30 patients who required treatment with more than one vasoactive or inotropic drug.Interventions:A multiple-drug closed-loop system integrated five single-drug blood pressure controllers. Arterial hypertension was controlled using sodium nitroprusside or nitroglycerin, arterial hypotension was controlled using noradrenaline or dobutamine, and pulmonary hypertension was controlled using nitroglycerin. The anesthesiologist selected target pressures and single-drug blood pressure controllers. The multiple-drug closed-loop system had a set of priority rules that automatically activated from the selected single-drug controllers the optimum single-drug controller for each hemodynamic state. Drug infusion rates of the nonactive controllers were kept constant. The initial knowledge that was used to construct the priority rules was obtained from standard anesthetic protocols on perioperative management of cardiac surgical patients. A supervisory computer program defined the actions to be taken in cases of infusion pump problems, invalid pressure measurements, and during unexpected increases and decreases in systemic arterial pressure.Measurements and Main Results:The activation of single-drug controllers by the priority rules was accurate and fast. On average, a different single-drug controller was activated once every 7.2 mins. As a measure of variability, the average deviation of mean arterial pressure and mean pulmonary artery pressure from their target values was evaluated and was 8.6 ± 4.0 and 4.4 ± 4.0 mm Hg, respectively, before cardiopulmonary bypass and 8.0 ± 3.6 and 2.4 ± 0.9 mm Hg, respectively, after cardiopulmonary bypass. None of the single-drug controllers showed any signs of unstable response.Conclusion:Closed-loop control of both arterial and pulmonary pressures using multiple drugs is feasible during cardiac surgery.

ISSN:0090-3493    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Objective:To perform a meta-analysis addressing whether enteral nutrition with immune-enhancing feeds benefits critically ill patients after trauma, sepsis, or major surgery.Data Sources:Studies were identified by MEDLINE search (1967 to January 1998) for original articles in English using the search terms "human," "enteral nutrition," "arginine," "nucleotides," "omega-3 fatty acids," "immunonutrition," "IMPACT," and "Immun-Aid." Additionally, the authors of the studies and the manufacturers of the feeds were contacted for additional information. Access to original databases was obtained for the three largest studies.Study Selection:Fifteen randomized controlled trials comparing patients receiving standard enteral nutrition with patients receiving a commercially available immune-enhancing feed with arginine with or without glutamine, nucleotides, and omega-3 fatty acids were identified by two independent reviewers (Dr. Beale and Dr. Bryg).Data Extraction:Descriptive and outcome data were extracted independently from the papers by the same two reviewers, one of whom (Dr. Bryg) analyzed the original databases. Three studies were excluded from analysis, leaving 12 studies containing 1,557 subjects, 1,482 of whom were analyzed. Main outcome measures were mortality, infection, ventilator days, intensive care unit stay, hospital stay, diarrhea days, calorie intake, and nitrogen intake. The meta-analysis was performed on an intent-to-treat basis.Data Synthesis:There was no effect of immunonutrition on mortality (relative risk = 1.05, confidence interval [CI] = 0.78, 1.41;p= .76). There were significant reductions in infection rate (relative risk = 0.67, CI = 0.50, 0.89;p= .006), ventilator days (2.6 days, CI = 0.1, 5.1;p= .04), and hospital length of stay (2.9 days, CI = 1.4, 4.4;p= .0002) in the immunonutrition group.Conclusions:The benefits of enteral immunonutrition were most pronounced in surgical patients, although they were present in all groups. The reduction in hospital length of stay and infections has resource implications.

ISSN:0090-3493    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Objectives:To investigate attitudes and practices regarding oxygen therapy in intensive care units (ICUs) and to devise quantitative descriptive indices.Setting:Canadian university-affiliated adult ICUs.Participants:Fifty-two medical directors of ICUs in 48 institutions.Intervention:Structured postal questionnaire returned by 48 participants.Measurements and Main Results:Attitudes, beliefs, and stated practices relating to oxygen use in ICUs were determined. Novel descriptors S-50min(minutes of oxygen saturation [SaO2] acceptable to >50% of respondents), F-50max(maximum FIO2above which <50% of respondents would increase FIO2), and F-50min(minimum FIO2below which <50% of respondents would decrease FIO2) were determined. All respondents believed that oxygen toxicity was a concern. Twenty-nine percent of respondents indicated that they did not always assess tissue oxygenation in critical cases. A stepwise reduction in acceptance of progressive desaturation and increasing duration of hypoxemia was found. Presented with a stable patient with SaO2of 98%, the maximum level of FIO2above which respondents stated that they would not increase the FIO2was 0.41 ± 0.17 (mean ± SD). For stable patients with SaO2of 85%, the minimum FIO2below which respondents would not reduce FIO2was 0.59 ± 0.23 (mean ± SD). F-50maxwas 0.8 vs. 0.5 for SaO2of 80%-85% vs. 85%-90%, respectively; F-50minwas 0.6 vs. 0.21 for SaO2of 90%-95% vs. 95%-100%, respectively.Conclusions:Considerable variation exists in the attitudes, beliefs, and stated practices relating to the management of oxygen therapy in the ICU. These data are amenable to quantitative description and illustrate the necessity for documentation of actual practice and development of support systems for decision-making in this and similar areas.

ISSN:0090-3493    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Objective:To evaluate the incidence and risk factors for clinically important upper gastrointestinal bleeding in critically ill patients requiring mechanical ventilation.Design:In duplicate, blinded adjudicators determined the presence of clinically important gastrointestinal bleeding usinga prioricriteria, evaluating relevant clinical, laboratory, and diagnostic data. Cox proportional hazards regression analyses were used to examine baseline and time-dependent risk factors for bleeding.Setting:Sixteen university-affiliated intensive care units (ICUs) in Canada.Patients:A total of 1,077 critically ill ICU patients ventilated for at least 48 hrs.Interventions:Patients were randomized to stress ulcer prophylaxis with intravenous ranitidine or nasogastric sucralfate; otherwise, management was at the discretion of the ICU team.Measurements and Main Results:Demographic data included patient characteristics, Acute Physiology and Chronic Health Evaluation II score, and multiple organ dysfunction (MOD) score. Each day in the ICU, physiologic measurements including MOD score, feeding, and other treatment variables were recorded. The significant risk factors for upper gastrointestinal bleeding in the univariable analyses were low platelet count, maximum serum creatinine, maximum MOD score, maximum pulmonary component of the MOD score, maximum hepatic component of the MOD score, maximum renal component of the MOD score, enteral nutrition, and stress ulcer prophylaxis with ranitidine. The only independent predictors of bleeding in the multivariable analysis were maximum serum creatinine (relative risk = 1.16 [95% confidence interval = 1.02-1.32]), enteral nutrition (relative risk = 0.30 [95% confidence interval = 0.13-0.67]), and ranitidine administration (relative risk = 0.39 [95% confidence interval = 0.17-0.83]).Conclusions:In critically ill ventilated patients, renal failure was independently associated with an increased risk of clinically important gastrointestinal bleeding, whereas enteral nutrition and stress ulcer prophylaxis with ranitidine conferred significantly lower bleeding rates.

ISSN:0090-3493    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Objective:To describe our experience with the use of percutaneous cardiopulmonary bypass as a therapy for cardiac arrest in an adult patient intoxicated with verapamil.Design:Case report.Setting:Emergency department of a university hospital.Patient:A patient with cardiac arrest after severe verapamil intoxication.Interventions:Percutaneous cardiopulmonary bypass and theophylline therapy.Case Report:A 41-yr-old white male had taken 4800-6400 mg of verapamil in a suicide attempt. On arrival of the ambulance physician, the patient was conscious with weak palpable pulses and was transported to a nearby hospital. The patient developed a pulseless electrical activity, and cardiopulmonary resuscitation was started. Despite all advanced life support efforts, the patient remained in cardiac arrest. Therefore, he was transferred under ongoing cardiopulmonary resuscitation to our department, where percutaneous cardiopulmonary bypass was initiated immediately (2.5 hrs after cardiac arrest). The first verapamil serum concentration obtained at admittance to our institution was 630 ng/mL. After several ineffective intravenous epinephrine applications, the administration of 0.48 g of theophylline as an intravenous bolus 6 hrs and 18 mins after cardiac arrest led to the return of spontaneous circulation. The patient remained stable and was transferred to an intensive care unit the same day. He woke up on the 12th day and was extubated on the 18th day. After transfer to a neuropsychiatric rehabilitation hospital, he recovered totally.Conclusion:In patients with cardiac arrest attributable to massive verapamil overdose, percutaneous extracorporeal cardiopulmonary bypass can provide adequate tissue perfusion and sufficient cerebral oxygen supply until the drug level is reduced and restoration of spontaneous circulation can be achieved.

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

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

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