A comparison of clinical outcomes and cost of radiofrequency catheter ablation for atrial fibrillation with monitored anesthesia care versus general anesthesia.

INTRODUCTION: Monitored anesthesia care (MAC) or general anesthesia (GA) can be used during catheter ablation (CA) of atrial fibrillation (AF). However, each approach may have advantages and disadvantages with variability in operator preferences. The optimal approach has not been well established. The purpose of this study was to compare procedural efficacy, safety, clinical outcomes, and cost of CA for AF performed with MAC versus GA. METHODS: The study population consisted of 810 consecutive patients (mean age: 63 ± 10 years, paroxysmal AF: 48%) who underwent a first CA for AF. All patients completed a preprocedural evaluation by the anesthesiologists. Among the 810 patients, MAC was used in 534 (66%) and GA in 276 (34%). Ten patients (1.5%) had to convert to GA during the CA. RESULTS: Although the total anesthesia care was longer with GA particularly in patients with persistent AF, CA was shorter by 5 min with GA than MAC (p < 0.01). Prevalence of perioperative complications was similar between the two groups (4% vs. 4%, p = 0.89). There was no atrioesophageal fistula with either approach. GA was associated with a small, ~7% increase in total charges due to longer anesthesia care. During 43 ± 17 months of follow-up after a single ablation procedure, 271/534 patients (51%) in the MAC and 129/276 (47%) patients in the GA groups were in sinus rhythm without concomitant antiarrhythmic drug therapy (p = 0.28). CONCLUSION: With the participation of an anesthesiologist, and proper preoperative assessment, CA of AF using GA or MAC has similar efficacy and safety.

Is Lactic Acidosis After Lung Transplantation Associated With Worse Outcomes?

BACKGROUND: Elevated lactate levels may be caused by increased production suggestive of tissue ischemia; however, they may also occur without evidence of ischemia, by catecholamine activation of beta receptors. The purpose of this study was to determine the factors associated with increased lactate levels during and after lung transplantation and to evaluate whether lactate levels were associated with increased time to extubation and postoperative complications. METHODS: This was a retrospective study of patients who underwent lung transplantation between January 2015 and May 2017 at the University of Michigan, Ann Arbor, MI. Multivariable linear regression was used to determine the factors associated with peak lactate levels and to find the associations between lactate levels and outcomes of nitric oxide time, intubation time, length of stay, and creatinine level. Logistic regression was used to determine the associations between lactate levels and acute kidney injury and atrial fibrillation. RESULTS: A total of 86 patients underwent single-lung transplantation (n = 17; 20%) or double-lung transplantation (n = 69; 80%). All patients initially had normal lactate levels. On univariate analysis, lactate levels at several time points were correlated with subsequent acute kidney injury, increased time to extubation, and increased nitric oxide time. After adjustment, the study found that higher peak intensive care unit lactate levels (regression coefficient B = 0.046; interquartile range, 0.006, 0.086; P = .025) were associated with longer length of stay. CONCLUSIONS: Cardiopulmonary bypass time, total ischemic time, and catecholamine use were associated with higher lactate levels, whereas nitric oxide and higher pulmonary artery pressures were associated with lower levels. Increased lactate levels were independently associated with longer intubation times, postoperative acute kidney injury, and longer length of stay.

Forbidden word entropy of cerebral oximetric values predicts postoperative neurocognitive decline in patients undergoing aortic arch surgery under deep hypothermic circulatory arrest.

PURPOSE: Up to 53% of cardiac surgery patients experience postoperative neurocognitive decline. Cerebral oximetry is designed to detect changes in cerebral tissue saturation and therefore may be useful to predict which patients are at risk of developing neurocognitive decline. METHODS: This is a retrospective analysis of a prospective study originally designed to determine if treatment of cerebral oximetry desaturation is associated with improvement in postoperative cognitive dysfunction in patients undergoing aortic reconstruction under deep hypothermic circulatory arrest. Cognitive function was measured, preoperatively and 3 months postoperatively, with 15 neuropsychologic tests administered by a psychologist; the individual test scores were summed and normalized. Bilateral cerebral oximetry data were stored and analyzed using measures of entropy. Cognitive decline was defined as any decrease in the summed normalized score from baseline to 3 months. RESULTS: Seven of 17 (41%) patients suffered cognitive decline. There was no association between baseline cerebral oximetry and postoperative cognitive dysfunction. Nor were changes in oximetry values associated with cognitive decline. However, cognitive decline was associated with loss of forbidden word entropy (FwEn) (correlation: Rho ρ = 0.51, P = 0.037 for left cerebral oximetry FwEn and ρ = 0.54, P = 0.025 for right cerebral oximetry FwEn). CONCLUSION: Postoperative cognitive decline was associated with loss of complexity of the time series as shown by a decrease in FwEn from beginning to end of the case. This suggests that regulation of cerebral oximetry is different between those who do and those who do not develop cognitive decline.

A retrospective analysis of the effect of blood transfusion on cerebral oximetry entropy and acute kidney injury.

PURPOSE: Acute anemia is associated with both cerebral dysfunction and acute kidney injury and is often treated with red blood cell transfusion. We sought to determine if blood transfusion changed the cerebral oximetry entropy, a measure of the complexity or irregularity of the oximetry values, and if this change was associated with subsequent acute kidney injury. METHODS: This was a retrospective, case-control study of patients undergoing cardiac surgery with cardiopulmonary bypass at a tertiary care hospital, comparing those who received a red blood cell transfusion to those who did not. Acute kidney injury was defined as a perioperative increase in serum creatinine by ⩾26.4 µmol/L or by ⩾50% increase. Entropy was measured using approximate entropy, sample entropy, forbidden word entropy and basescale4 entropy in 500-point sets. RESULTS: Forty-four transfused patients were matched to 88 randomly selected non-transfused patients. All measures of entropy had small changes in the transfused group, but increased in the non-transfused group (p<0.05, for all comparisons). Thirty-five of 132 patients (27%) suffered acute kidney injury. Based on preoperative factors, patients who suffered kidney injury were similar to those who did not, including baseline cerebral oximetry levels. After analysis with hierarchical logistic regression, the change in basescale4 entropy (odds ratio = 1.609, 95% confidence interval = 1.057-2.450, p = 0.027) and the interaction between basescale entropy and transfusion were significantly associated with subsequent development of acute kidney injury. CONCLUSIONS: The transfusion of red blood cells was associated with a smaller rise in entropy values compared to non-transfused patients, suggesting a change in the regulation of cerebral oxygenation, and these changes in cerebral oxygenation are also associated with acute kidney injury.

Postoperative metabolic acidosis following the minimally invasive radiofrequency maze procedure.

PURPOSE: Atrial fibrillation (AF) is the most common arrhythmia treated in the world. While medical treatment with antiarrhythmic drugs remains the primary treatment modality, symptomatic refractory AF often requires treatment with a catheter or surgical ablation. One minimally invasive therapy is the Mini-Maze procedure, which utilizes epicardial radiofrequency ablation via a subxiphoid approach to rid the heart of arrhythmogenic atrial foci without a median sternotomy or cardiopulmonary bypass. The goal of this retrospective cohort study was to identify clinical factors associated with metabolic acidosis following the Mini-Maze procedure. MATERIALS AND METHODS: After Institutional Review Board approval, we studied patients undergoing the Mini-Maze procedure, off-pump coronary artery bypass grafting or patients conventional Cox-Maze on cardiopulmonary bypass. The first base deficit value obtained in the Intensive Care Unit was used as a measure of metabolic acidosis. Using logistic regression with Akaike information criteria, we analyzed preoperative, intraoperative, and postoperative data to determine the factors associated with changes in base deficit. RESULTS: A multivariable model using stepwise selection demonstrated that diabetes mellitus and weight were associated with a decrease in the base deficit by 2.87 mEq/L (95% CI: -5.55--0.19) and 0.04 mEq/L (95%CI: -0.08, 0.004), respectively. Furthermore, creatinine was associated with a 1.57 mEq/L (95% CI: 0.14, 2.99) increase in the base deficit. CONCLUSION: The Mini-Maze procedure was not associated with postoperative metabolic acidosis. Instead, nondiabetic patients and patients with higher creatinine were associated with greater base deficits after undergoing cardiac surgery.

Perioperative management of bridge-to-lung transplant using ECMO.

Respiratory failure requiring intubation has traditionally been a relative contraindication to lung transplantation due to increased morbidity and mortality. Advances in extracorporeal membranous oxygenation (ECMO) have made it possible to extubate patients and provide physical therapy with minimal native lung function. By "bridging" patients to lung transplant using ECMO, they are able to undergo rehabilitation and withstand the demands of surgery. However, providing anesthesia for these cases requires an understanding of ECMO physiology and the pharmacology associated with ECMO. We describe the anesthetic for four patients who were bridged to lung transplant and the complexities of their perioperative management.

Dexmedetomidine as a novel therapeutic for postoperative pain in a patient treated with buprenorphine.

Buprenorphine is a partial agonist/antagonist used for the outpatient management of pain and addiction. It avidly binds to the opioid receptors and has a long and varied half-life. Its effects can impair the efficacy of opioids used for postoperative pain. The authors present a case of a patient managed with buprenorphine as an outpatient who presented for revision spine surgery and had significant postoperative pain that was successfully treated with hydromorphone and dexmedetomidine. This is the first reported use of dexmedetomidine for postoperative pain in a patient treated with buprenorphine.

Severe chronic venous insufficiency: magnitude of the problem and consequences.

The aim of this study was to characterize patients requiring hospitalization for severe chronic venous insufficiency (CVI) at the local and national levels and to analyze factors related to primary amputation. An administrative database (Nationwide Inpatient Sample, 1988-2000) and a single institution (1992-2000) were reviewed using the International Classification of Diseases, 9th ed., Clinical Modification, codes for CVI, excluding phlegmasia and concomitant peripheral vascular occlusive disease codes. Demographics, clinical course, and outcomes were assessed. Descriptive, univariate, and multivariate statistical analyses were used; p < 0.05 was considered significant. Nationally, CVI occurred with a mean incidence of 92/100,000 admissions, of which 55% were women, having a mean age of 65 years and a median length of stay of 7 days. Mean hospital charges were $13,900 and did not change significantly over time. Acute deep vein thrombosis affected 1.3%, amputation was performed in 1.2%, and in-hospital mortality was 1.6% The local cohort included 67 patients with a mean age of 51 years; a majority were men (60%), and 85% were C6 (of Clinical-Etiologic-Anatomic-Pathophysiology [CEAP]). Patients averaged 23 clinic visits and a median of one hospitalization for CVI care over a 44-month follow-up. Twelve patients (18%) underwent a CVI-related amputation (one transmetatarsal amputation, nine below-knee amputations, and two above-knee amputations). They had fourfold more CVI-related hospitalizations, greater preoperative chronic narcotic use than nonamputee patients (85% vs. 58%), but less ongoing wound care needs (25% vs. 89%) (all p values < 0.05). However, no significant difference in long-term mortality, number of clinic visits, duration of symptoms, antibiotic courses, or prior venous-related surgeries was found. In those with amputation, ambulatory status was maintained in 75% at 15-month follow-up. The physiological and economic costs of severe CVI are significant and have not decreased over more than a decade. Amputation for CVI-related nonhealing wounds has a reasonable outcome. Future therapy must focus on prevention of CVI sequelae.