Preoperative and intraoperative predictors of postoperative acute respiratory distress syndrome in a general surgical population.

BACKGROUND: Acute respiratory distress syndrome (ARDS) is a devastating condition with an estimated mortality exceeding 30%. There are data suggesting risk factors for ARDS development in high-risk populations, but few data are available in lower incidence populations. Using risk-matched analysis and a combination of clinical and research data sets, we determined the incidence and risk factors for the development of ARDS in this general surgical population. METHODS: We conducted a review of common adult surgical procedures completed between June 1, 2004 and May 31, 2009 using an anesthesia information system. This data set was merged with an ARDS registry and an institutional death registry. Preoperative variables were subjected to multivariate analysis. Matching and multivariate regression was used to determine intraoperative factors associated with ARDS development. RESULTS: In total, 50,367 separate patient admissions were identified, and 93 (0.2%) of these patients developed ARDS. Preoperative risk factors for ARDS development included American Society of Anesthesiologist status 3-5 (odds ratio [OR] 18.96), emergent surgery (OR 9.34), renal failure (OR 2.19), chronic obstructive pulmonary disease (OR 2.16), number of anesthetics during the admission (OR 1.37), and male sex (OR 1.65). After matching, intraoperative risk factors included drive pressure (OR 1.17), fraction inspired oxygen (OR 1.02), crystalloid administration in liters (1.43), and erythrocyte transfusion (OR 5.36). CONCLUSIONS: ARDS is a rare condition postoperatively in the general surgical population and is exceptionally uncommon in low American Society of Anesthesiologists status patients undergoing scheduled surgery. Analysis after matching suggests that ARDS development is associated with median drive pressure, fraction inspired oxygen, crystalloid volume, and transfusion.

A randomized trial of recombinant human granulocyte-macrophage colony stimulating factor for patients with acute lung injury.

RATIONALE: Despite recent advances in critical care and ventilator management, acute lung injury and acute respiratory distress syndrome continue to cause significant morbidity and mortality. Granulocyte-macrophage colony stimulating factor may be beneficial for patients with acute respiratory distress syndrome. OBJECTIVES: To determine whether intravenous infusion of granulocyte-macrophage colony stimulating factor would improve clinical outcomes for patients with acute lung injury/acute respiratory distress syndrome. DESIGN: A randomized, double-blind, placebo-controlled clinical trial of human recombinant granulocyte-macrophage colony stimulating factor vs. placebo. The primary outcome was days alive and breathing without mechanical ventilatory support within the first 28 days after randomization. Secondary outcomes included mortality and organ failure-free days. SETTING: Medical and surgical intensive care units at three academic medical centers. PATIENTS: One hundred thirty individuals with acute lung injury of at least 3 days duration were enrolled, out of a planned cohort of 200 subjects. INTERVENTIONS: Patients were randomized to receive human recombinant granulocyte-macrophage colony stimulating factor (64 subjects, 250 µg/M) or placebo (66 subjects) by intravenous infusion daily for 14 days. Patients received mechanical ventilation using a lung-protective protocol. MEASUREMENTS AND MAIN RESULTS: There was no difference in ventilator-free days between groups (10.7 ± 10.3 days placebo vs. 10.8 ± 10.5 days granulocyte-macrophage colony stimulating factor, p = .82). Differences in 28-day mortality (23% in placebo vs. 17% in patients receiving granulocyte-macrophage colony stimulating factor (p = .31) and organ failure-free days (12.8 ± 11.3 days placebo vs. 15.7 ± 11.9 days granulocyte-macrophage colony stimulating factor, p = .16) were not statistically significant. There were similar numbers of serious adverse events in each group. CONCLUSIONS: In a randomized phase II trial, granulocyte-macrophage colony stimulating factor treatment did not increase the number of ventilator-free days in patients with acute lung injury/acute respiratory distress syndrome. A larger trial would be required to determine whether treatment with granulocyte-macrophage colony stimulating factor might alter important clinical outcomes, such as mortality or multiorgan failure. (ClinicalTrials.gov number, NCT00201409 [ClinicalTrials.gov]).

A description of intraoperative ventilator management in patients with acute lung injury and the use of lung protective ventilation strategies.

BACKGROUND: The incidence of acute lung injury (ALI) in hypoxic patients undergoing surgery is currently unknown. Previous studies have identified lung protective ventilation strategies that are beneficial in the treatment of ALI. The authors sought to determine the incidence and examine the use of lung protective ventilation strategies in patients receiving anesthetics with a known history of ALI. METHODS: The ventilation parameters that were used in all patients were reviewed, with an average preoperative PaO2/Fio2 [corrected] ratio of ≤ 300 between January 1, 2005 and July 1, 2009. This dataset was then merged with a dataset of patients screened for ALI. The median tidal volume, positive end-expiratory pressure, peak inspiratory pressures, fraction inhaled oxygen, oxygen saturation, and tidal volumes were compared between groups. RESULTS: A total of 1,286 patients met criteria for inclusion; 242 had a diagnosis of ALI preoperatively. Comparison of patients with ALI versus those without ALI found statistically yet clinically insignificant differences between the ventilation strategies between the groups in peak inspiratory pressures and positive end-expiratory pressure but no other category. The tidal volumes in cc/kg predicted body weight were approximately 8.7 in both groups. Peak inspiratory pressures were found to be 27.87 cm H2O on average in the non-ALI group and 29.2 in the ALI group. CONCLUSION: Similar ventilation strategies are used between patients with ALI and those without ALI. These findings suggest that anesthesiologists are not using lung protective ventilation strategies when ventilating patients with low PaO2/Fio2 [corrected] ratios and ALI, and instead are treating hypoxia and ALI with higher concentrations of oxygen and peak pressures.

An overview of end-of-life issues in the intensive care unit.

The population of the earth is aging, and as medical techniques, pharmaceuticals, and devices push the boundaries of human physiological capabilities, more humans will go on to live longer. However, this prolonged existence may involve incapacities, particularly at the end-of-life, and especially in the intensive care unit. This arena involves not only patients and families, but also care givers. It involves topics from economics to existentialism, and surgery to spiritualism. It requires education, communication, acceptance of diversity, and an ultimate acquiescence to the inevitable. Here, we present a comprehensive overview of issues in the care of patients at the end-of-life stage that may cause physicians and other healthcare providers, medical, ethical, social, and philosophical concerns in the intensive care unit.

Development and validation of an acute kidney injury risk index for patients undergoing general surgery: results from a national data set.

BACKGROUND: The authors sought to identify the incidence, risk factors, and mortality impact of acute kidney injury (AKI) after general surgery using a large and representative national clinical data set. METHODS: The 2005-2006 American College of Surgeons-National Surgical Quality Improvement Program participant use data file is a compilation of outcome data from general surgery procedures performed in 121 US medical centers. The primary outcome was AKI within 30 days, defined as an increase in serum creatinine of at least 2 mg/dl or acute renal failure necessitating dialysis. A variety of patient comorbidities and operative characteristics were evaluated as possible predictors of AKI. A logistic regression full model fit was used to create an AKI model and risk index. Thirty-day mortality among patients with and without AKI was compared. RESULTS: Of 152,244 operations reviewed, 75,952 met the inclusion criteria, and 762 (1.0%) were complicated by AKI. The authors identified 11 independent preoperative predictors: age 56 yr or older, male sex, emergency surgery, intraperitoneal surgery, diabetes mellitus necessitating oral therapy, diabetes mellitus necessitating insulin therapy, active congestive heart failure, ascites, hypertension, mild preoperative renal insufficiency, and moderate preoperative renal insufficiency. The c statistic for a simplified risk index was 0.80 in the derivation and validation cohorts. Class V patients (six or more risk factors) had a 9% incidence of AKI. Overall, patients experiencing AKI had an eightfold increase in 30-day mortality. CONCLUSIONS: Approximately 1% of general surgery cases are complicated by AKI. The authors have developed a robust risk index based on easily identified preoperative comorbidities and patient characteristics.

Preoperative and intraoperative predictors of cardiac adverse events after general, vascular, and urological surgery.

BACKGROUND: The authors sought to determine the incidence and risk factors for perioperative cardiac adverse events (CAEs) after noncardiac surgery using detailed preoperative and intraoperative hemodynamic data. METHODS: The authors conducted a prospective observational study at a single university hospital from 2002 to 2006. All American College of Surgeons-National Surgical Quality Improvement Program patients undergoing general, vascular, and urological surgery were included. The CAE outcome definition included cardiac arrest, non-ST elevation myocardial infarction, Q-wave myocardial infarction, and new clinically significant cardiac dysrhythmia within the first 30 postoperative days. RESULTS: Four years of data demonstrated that of 7,740 noncardiac operations, 83 patients (1.1%) experienced a CAE within 30 days. Nine independent predictors were identified (P < or = 0.05): age > or = 68, body mass index > or = 30, emergent surgery, previous coronary intervention or cardiac surgery, active congestive heart failure, cerebrovascular disease, hypertension, operative duration > or = 3.8 h, and the administration of 1 or more units of packed red blood cells intraoperatively. The c-statistic of this model was 0.81 +/- 0.02. Univariate analysis demonstrated that high-risk patients experiencing a CAE were more likely to experience an episode of mean arterial pressure < 50 mmHg (6% vs. 24%, P = 0.02), experience an episode of 40% decrease in mean arterial pressure (26% vs. 53%, P = 0.01), and an episode of heart rate > 100 (22% vs. 34%, P = 0.05). CONCLUSIONS: In comparison with current risk stratification indices, the inclusion of intraoperative elements improves the ability to predict a perioperative CAE after noncardiac surgery.

Predictors of postoperative acute renal failure after noncardiac surgery in patients with previously normal renal function.

BACKGROUND: The authors investigated the incidence and risk factors for postoperative acute renal failure after major noncardiac surgery among patients with previously normal renal function. METHODS: Adult patients undergoing major noncardiac surgery with a preoperative calculated creatinine clearance of 80 ml/min or greater were included in a prospective, observational study at a single tertiary care university hospital. Patients were followed for the development of acute renal failure (defined as a calculated creatinine clearance of 50 ml/min or less) within the first 7 postoperative days. Patient preoperative characteristics and intraoperative anesthetic management were evaluated for associations with acute renal failure. Thirty-day, 60-day, and 1-yr all-cause mortality was also evaluated. RESULTS: A total of 65,043 cases between 2003 and 2006 were reviewed. Of these, 15,102 patients met the inclusion criteria; 121 patients developed acute renal failure (0.8%), and 14 required renal replacement therapy (0.1%). Seven independent preoperative predictors were identified (P < 0.05): age, emergent surgery, liver disease, body mass index, high-risk surgery, peripheral vascular occlusive disease, and chronic obstructive pulmonary disease necessitating chronic bronchodilator therapy. Several intraoperative management variables were independent predictors of acute renal failure: total vasopressor dose administered, use of a vasopressor infusion, and diuretic administration. Acute renal failure was associated with increased 30-day, 60-day, and 1-yr all-cause mortality. CONCLUSIONS: Several preoperative predictors previously reported to be associated with acute renal failure after cardiac surgery were also found to be associated with acute renal failure after noncardiac surgery. The use of vasopressor and diuretics is also associated with acute renal failure.

Neoadjuvant chemotherapy and radiotherapy for large extremity soft-tissue sarcomas.

PURPOSE: Treatment of extremity soft-tissue sarcomas yields excellent local control, but distant failure is common with large, high-grade tumors. A regimen of preoperative chemotherapy consisting of mesna, adriamycin, ifosfamide, and dacarbazine (MAID) interdigitated with radiotherapy followed by resection and postoperative chemotherapy with or without radiotherapy was designed to improve treatment outcome. We report the mature outcome data on 48 treated patients and compare them with the data of an historical matched control patient population. METHODS AND MATERIALS: Adult patients with high-grade extremity soft-tissue sarcomas >or=8 cm were treated with three cycles of preoperative chemotherapy combined with 44 Gy of radiotherapy followed by surgery. Three cycles of postoperative MAID were planned. For patients with positive surgical margins, 16 Gy was delivered postoperatively. RESULTS: All 48 patients (M0) received the MAID protocol treatment, and their outcome was superior to that of the historical control patients. The 5-year actuarial local control, freedom from distant metastasis, disease-free survival, and overall survival rate was 92% and 86% (p = 0.1155), 75% and 44% (p = 0.0016), 70% and 42% (p = 0.0002), and 87% and 58% (p = 0.0003) for the MAID and control patient groups, respectively. Acute hematologic toxicity in the MAID group included febrile neutropenia in 12 patients (25%). Wound healing complications occurred in 14 (29%) of 48 MAID patients. One MAID patient developed late fatal myelodysplasia. CONCLUSION: After aggressive chemoradiation and surgery, these patients showed a significant reduction in distant metastases, with a highly significant gain in disease-free and overall survival compared with a historical control group. On the basis of this experience, the Radiation Therapy Oncology Group conducted a multi-institutional trial.