C. Allen Bashour

Effects of single dose, postinduction dexamethasone on recovery after cardiac surgery

BACKGROUND Corticosteroids have been recommended to facilitate rapid recovery after cardiac surgery. We previously reported that dexamethasone given after induction of anesthesia decreases the incidence of postoperative shivering. We performed a post hoc analysis of the data obtained during that study, focusing on secondary outcomes. METHODS A total of 235 adult patients undergoing elective coronary or valvular heart surgery were randomized to receive dexamethasone 0.6 mg/kg or placebo after induction of anesthesia. Patients who had pharmacologically treated diabetes mellitus, had hypersensitivity to dexamethasone, or were receiving treatment with corticosteroids were excluded. RESULTS We found that, compared with placebo, patients receiving dexamethasone were more likely to remain tracheally intubated for 6 hours or less (26.4% vs 10.0%, p = 0.020) and had a lower incidence of early postoperative fever (20.2% vs 36.8%, p = 0.009) and new-onset atrial fibrillation during the first 3 days postoperatively (18.9% vs 32.3%, p = 0.027). However, we could not demonstrate a statistical difference in the intensive care unit or hospital length of stay, or in overall morbidity and mortality. The dexamethasone-treated patients were also more likely to have a higher blood glucose on admission to the intensive care unit (186 mg/dL vs 143 mg/dL, p = 0.012). CONCLUSIONS Dexamethasone facilitates early tracheal extubation and is associated with a lower incidence of early postoperative fever and new-onset atrial fibrillation. Apart from a treatable decreased glucose tolerance, dexamethasone treatment was not shown to affect morbidity or mortality significantly.

Renal dose dopamine is associated with the risk of new-onset atrial fibrillation after cardiac surgery

Objective:“Renal dose” dopamine (rDA; 1–3 &mgr;g/kg per min) is administered to patients after cardiac surgery to preserve or improve renal function. Many of these patients develop new-onset postoperative atrial fibrillation or atrial flutter (pAF) that could be related to rDA administration. The objective of this investigation was to determine whether there was an association between rDA and new-onset pAF in patients undergoing coronary artery bypass grafting with cardiopulmonary bypass (CABG). Setting:Research hospital. Subjects:The study population consisted of 1,731 patients undergoing CABG. Interventions:CABG with and without rDA. Design:After approval by the institutional review board, a retrospective study using the Cardiothoracic Anesthesia Patient Registry was undertaken to determine the association between rDA and pAF in patients undergoing CABG. Patients with a documented history of atrial fibrillation, those who required inotrope use during or after surgery, and those having valve surgery were excluded. Measurements and Main Results:One-thousand seven-hundred thirty-one patients undergoing CABG during the period of January 1, 2000, through June 30, 2002, were the study population; of these, 15.0% (260/1,731) developed pAF. The incidence of pAF was 23.3 % (41/176) among patients who received rDA and 14.1% (219/1,555) among those who did not receive rDA. In the multivariable logistic regression model, patient age, gender, chronic obstructive pulmonary disease or asthma, and rDA were associated with pAF (p < .01). Receipt of rDA increased the odds of developing pAF by 74%, independent of the effect of other variables. Conclusions:Renal-dose dopamine is associated with a 1.74 odds ratio of pAF developing after CABG.

Outcome in Patients Who Require Venoarterial Extracorporeal Membrane Oxygenation Support After Cardiac Surgery

OBJECTIVE The authors analyzed hospital mortality in adult cardiac surgery patients who required postoperative venoarterial extracorporeal membrane oxygenation (ECMO) support for circulatory failure and identified perioperative patient variables associated with hospital mortality in these patients. DESIGN A retrospective study. SETTING A single institution, tertiary academic center. PARTICIPANTS Adult patients requiring venoarterial ECMO support after cardiac surgery from January 1995 to December 2005 were identified from the Anesthesiology Institute Patient Registry. Twenty-two preselected patient variables were entered into a logistic regression model of hospital death. INTERVENTIONS None. RESULTS Two hundred thirty-three of 40,116 (0.58%) adult cardiac surgery patients required postoperative venoarterial ECMO, and among these, 149 (64%) died in the hospital. In an unadjusted analysis, older age, higher preoperative albumin, diabetes history, coronary artery bypass graft surgery, and longer total cardiopulmonary bypass (CPB) time were associated with increased hospital mortality, and a history of cardiogenic shock was associated with decreased mortality. In an adjusted logistic regression analysis, a history of cardiogenic shock and younger age were associated with decreased hospital mortality. The overall use of postoperative venoarterial ECMO in this patient population decreased since its peak in 1996. CONCLUSION Venoarterial ECMO support after cardiac surgery was required in a small fraction of patients and was associated with very high hospital mortality; but among those requiring ECMO, mortality in these patients was lower in younger, nondiabetic patients with cardiogenic shock who had shorter CPB times. The mortality associated patient variables identified are not easily modifiable and do not appear sufficiently robust to define which patients should be selected for this potentially life-saving therapy.

A prospective observational study of the effect of penicillin skin testing on antibiotic use in the intensive care unit

BACKGROUND Patients with penicillin allergy admitted to the intensive care unit (ICU) frequently receive non-beta-lactam antimicrobials for the treatment of infection. The use of these antimicrobials, more commonly vancomycin and fluoroquinolones, is associated with the emergence of multidrug-resistant infections. The penicillin skin test (PST) can help detect patients at risk of developing an immediate allergic reaction to penicillin and those patients with a negative PST may be able to use a penicillin antibiotic safely. METHODS We determined the incidence of true penicillin allergy, the percentage of patients changed to a beta-lactam antimicrobial when the test was negative, the safety of the test, and the safety of administration of beta-lactam antimicrobials in patients with a negative test. Skin testing was performed using standard methodology. RESULTS One hundred patients admitted to 4 ICUs were prospectively studied; 58 of them were male. The mean age was 63 years. Ninety-six patients had the PST: one was positive (1.04%), 10 (10.4%) were nondiagnostic, and 85 (88.5%) were negative. Of the 38 patients who received antimicrobials for therapeutic reasons, 31(81.5%) had the antibiotic changed to a beta-lactam antimicrobial after a negative reading versus 7 patients of the 57 (12%) who had received a prophylactic antimicrobial (P < .001). No adverse effects were reported after the PST or after antimicrobial administration. CONCLUSIONS The PST is a safe, reliable, and effective strategy to reduce the use of non-beta-lactam antimicrobials in patients who are labeled as penicillin allergic and admitted to the ICU.

Dexamethasone Decreases the Incidence of Shivering After Cardiac Surgery: A Randomized, Double-Blind, Placebo-Controlled Study

Shivering after cardiac surgery is common, and may be a result of intraoperative hypothermia.Another possible etiology is fever and chills secondary to activation of the inflammatory response and release of cytokines by cardiopulmonary bypass. Dexamethasone decreases the gradient between core and skin temperature and modifies the inflammatory response. The goal of this study was to determine whether dexamethasone can reduce the incidence of shivering. Two hundred thirty-six patients scheduled for elective coronary and/or valvular surgery were randomly assigned to receive either dexamethasone 0.6 mg/kg or placebo after the induction of anesthesia. All patients received standard monitoring and anesthetic management. After arrival in the intensive care unit (ICU), nurses unaware of the treatment groups recorded visible shivering, as well as skin and pulmonary artery temperatures. Analysis of shivering rates was performed by using chi squared tests and logistic regression analysis. Compared with placebo, dexamethasone decreased the incidence of shivering (33.0% vs 13.1%; P = 0.001). It was an independent predictor of reduced incidence of shivering and was also associated with a higher skin temperature on ICU admission and a lower central temperature in the early postoperative period. Implications: Dexamethasone is effective in decreasing the incidence of shivering. The effectiveness of dexamethasone is independent of temperature and duration of cardiopulmonary bypass. Shivering after cardiac surgery may be part of the febrile response that occurs after release of cytokines during cardiopulmonary bypass. (Anesth Analg 1998;87:795-9)

Have Changes in ECMO Technology Impacted Outcomes in Adult Patients Developing Postcardiotomy Cardiogenic Shock

Abstract  Extracorporeal membrane oxygenation (ECMO) technology has undergone several advancements over the last decade. We sought to compare current ECMO technology to older ones to determine how these technological improvements have impacted outcomes in patients suffering from postcardiotomy cardiogenic shock (PCS). Between 2005 and 2010, 49 patients received ECMO as support for PCS following elective cardiac surgery. Patients were divided into three groups. Group 1 (Gp 1, n = 11) patients received a Biomedicus pump with an Affinity oxygenator, Group 2 (Gp 2, n = 11) patients received a Biomedicus pump with a Quadrox D oxygenator, and Group 3 (Gp 3, n = 27) patients received a Rotaflow pump with a Quadrox D oxygenator. Groups were compared with regards to adverse events and ability to wean. Adverse event analysis showed no statistically significant difference between groups in incidence of stroke (p = 0.08), renal failure (p = 0.88), or bleeding requiring reexploration (p = 0.10). Changes in technology did little to improve weaning rates from ECMO (Gp 1 = 63.6%, Gp 2 = 45.5%, and Gp 3 = 55.6%). Similar trends were detected in hospital survival (Gp 1 = 27.3%, Gp 2 = 27.3%, and Gp 3 = 33.3%). Technology did impact oxygenator durability with Gp 1 requiring seven (63.6%) oxygenator exchanges compared to zero (0.0%) in Gp 2 and two (7.4%) in Gp 1. While advancements in ECMO technology have resulted in improved oxygenator durability, outcomes in patients requiring such support for PCS continue to be poor.

Early tracheostomy is associated with improved outcomes in patients who require prolonged mechanical ventilation after cardiac surgery

BACKGROUND The best time to perform a tracheostomy in cardiac surgery patients who require prolonged postoperative mechanical ventilation remains unknown. The primary aim of this investigation was to determine if tracheostomy performed before postoperative day 10 improves patient outcomes. STUDY DESIGN We conducted a retrospective review of prospectively collected patient information obtained from the Anesthesiology Institute Patient Registry on adult patients recovering from coronary artery bypass grafting and/or valve surgery. Demographic and comorbidity patient variables were obtained. Patients were divided into 2 groups based on the timing of their tracheostomy: early (less than 10 days) and late (14 to 28 days). The 2 patient groups were matched using propensity scores and compared on morbidity and in-hospital mortality outcomes. The primary outcomes measures were length of stay, morbidity, and in-hospital mortality. RESULTS After propensity matching (n = 114 patients/group), early tracheostomy was associated with decreased in-hospital mortality (21.1% vs 40.4%, p = 0.002) and cardiac morbidity (14.0% vs 33.3%, p < 0.001), along with decreased ICU (median difference 7.2 days, p < 0.001) and hospital (median difference 7.5 days, p = 0.010) durations. The occurrence of sternal wound infection (6.0% vs 19.5%, p = 0.009) was less in the early tracheostomy group, but mediastinitis did not differ significantly (3.5% vs 7.0%, p = 0.24). CONCLUSIONS Tracheostomy within 10 postoperative days in cardiac surgery patients who require prolonged mechanical ventilation was associated with decreased length of stay, morbidity, and mortality.

Benzocaine-induced methemoglobinemia.

T here have been 58 reported cases of benzocaineinduced methemoglobinemia since Bernstein (1) first described the condition in 1950. Although it occurs infrequently, benzocaine-induced methemoglobinemia is a potentially fatal complication if not promptly diagnosed and treated. We report a case of methemoglobinemia after topical use of benzocaine in preparation for bronchoscopy and subsequent endotracheal intubation.

Lactate Clearance Time and Concentration Linked to Morbidity and Death in Cardiac Surgical Patients

BACKGROUND Early predictors of morbidity after cardiac operations are lacking. Elevated lactate concentrations in the immediate postoperative period reflect unmet metabolic demand and may be associated with outcome. This study examined the association between early plasma lactate concentrations and outcome after cardiac operations. METHODS As a retrospective cohort investigation, patient information was obtained from the Cardiovascular Information and the Anesthesiology Institutes patient registries. Inclusion criteria were all adult cardiac surgical patients undergoing isolated coronary artery bypass grafting or valve procedures, or coronary artery bypass grafting with a valve procedure, from January 1, 2008, to August 7, 2008 (arterial lactate values were added to the patient registry beginning January 1, 2008). RESULTS Lactate concentrations during the initial 12 postoperative hours of a patients stay in the cardiovascular intensive care unit were averaged (mean lactate concentration), and linear regression concentrations over time were used to predict when the lactate concentration would reach 1.5 mmol/L in individual patients (predicted lactate clearance time). We also considered the product of the mean and clearance (product value). Predicted lactate clearance time, mean lactate concentration, and product value were associated with any type of reoperation, death, and a set of composite outcomes (p < 0.001 for each). The accuracy of these indices was moderate to good, with the highest C statistic (for product value) being 0.82. CONCLUSIONS Predicted lactate clearance time, mean lactate concentration, and product value are each associated with death, any type of reoperation, and a set of composite outcomes in patients undergoing coronary artery bypass grafting or valve operations, or both. Product value provided the best early prognostic guidance in individual patients.

Operation timing does not affect outcome after coronary artery bypass graft surgery.

Background:Human factors such as fatigue, circadian rhythms, scheduling, and staffing may have an impact on patient care over the course of a day across all medical specialties. Research by the transportation industry concludes that human performance is degraded by shift work, circadian rhythm disturbances, and prolonged duty. This study investigated whether the timing of coronary artery bypass graft surgery affects outcomes. Methods:The outcomes of coronary artery bypass graft surgery patients were analyzed according to the hour of the day, day of the workweek, month, and moon phase in which the surgery started. All patients who underwent isolated coronary artery bypass graft surgery between January 1, 1993 and July 1, 2006 were considered for the study.The primary outcome measurement was a compound morbidity outcome of six variables defined by the Society of Thoracic Surgeons. These outcomes included (1) in-hospital death, (2) acute postoperative myocardial infarction, (3) neurologic morbidity, including focal or global neurologic deficits or death without awakening, (4) serious infection morbidity consisting of sepsis syndrome or septic shock, (5) new-onset renal failure requiring dialysis, and (6) postoperative ventilatory support exceeding 72 h. Results:The composite morbidity and in-hospital mortality rates were 4.8% and 1.4%, respectively. The number of cases each weekday, each month of the year, and during each phase of the moon were consistent. None of the time factors significantly affected the composite morbidity outcome. Conclusions:Elective coronary artery bypass graft surgery can be scheduled throughout the workday, any day of the work week and in any month of the year without compromising outcome.