Julie L. Huffmyer

Preoperative Statin Administration Is Associated With Lower Mortality and Decreased Need for Postoperative Hemodialysis in Patients Undergoing Coronary Artery Bypass Graft Surgery

OBJECTIVE The purpose of this study was to examine the effect of perioperative statin administration on renal outcomes after cardiac surgery. DESIGN A retrospective chart review. SETTING A university hospital. PARTICIPANTS Patients presenting for cardiac surgery. INTERVENTIONS The records of 2,760 patients admitted for coronary artery bypass graft (CABG) surgery from 1997 to 2006 were reviewed. In-hospital mortality, the need for renal replacement therapy (RRT), and acute renal failure (ARF) were considered the primary outcomes. Univariate and multiple logistic regression analyses were performed to assess the relationship between each outcome and statin therapy while adjusting for other patient characteristics. MAIN RESULTS Of the 2,760 patients, 1,557 were taking preoperative statins. On univariate analysis, the mortality rate for patients receiving statins was 2.4% versus 4.2% for those not receiving statins (p = 0.008). The requirement for RRT was 1.9% for patients receiving statins versus 3.6% for those not receiving statins (p = 0.011). The incidence of ARF was not statistically significant between groups (28% v 27.5%). On multivariate analysis, statin therapy was associated with a 43% decrease in the risk of death and a 46% decrease in the risk of RRT, but statins were not associated with a decreased risk of ARF. Also, the beneficial effects of statins were age-dependent, with younger patients experiencing a greater advantage. CONCLUSIONS The preoperative use of statins is associated with decreased in-hospital mortality and a reduction in the need for RRT.

Physiology and pharmacology of myocardial preconditioning and postconditioning.

Perioperative myocardial ischemia and infarction are not only major sources of morbidity and mortality in patients undergoing surgery but also important causes of prolonged hospital stay and resource utilization. Ischemic and pharmacological preconditioning and postconditioning have been known for more than 2 decades to provide protection against myocardial ischemia and reperfusion and limit myocardial infarct size in many experimental animal models, as well as in clinical studies. This article reviews the physiology and pharmacology of ischemic and drug-induced preconditioning and postconditioning of the myocardium with special emphasis on the mechanisms by which volatile anesthetics provide myocardial protection. Insights gained from animal and clinical studies are reviewed and recommendations given for the use of perioperative anesthetics and medications.

Perioperative Management of the Adult with Cystic Fibrosis

Since cystic fibrosis (CF) was first differentiated from celiac disease in 1938, the medical care of patients with CF has substantially improved. These improvements have resulted in a significant increase in median survival and the quality of life experienced by patients. The resultant increase in survival has caused the “average” CF patient to be a young adult and not a child. The gene that causes CF was first identified in 1989 and is the first gene discovered by positional cloning. Unfortunately, gene therapy for CF has not been successful, although it continues to hold great promise for future patient care. Although pulmonary disease is responsible for more than 90% of the morbidity and mortality in patients with CF, they also experience pancreatic disease, including diabetes mellitus, bone disease, hepatobiliary disease, and genitourinary disease. The optimal perioperative management of patients with CF requires an understanding of the relevant pathophysiology and the unique challenges presented by these patients. We reviewed these concepts, including special considerations such as liver and lung transplantation and pregnancy.

Management of the Patient for Transcatheter Aortic Valve Implantation in the Perioperative Period

Aortic stenosis is a prevalent valvular disease among aging patients, and surgical correction is the most definitive treatment. Yet many elderly patients are deemed to be “inoperable” or at excessive risk to undergo open surgical aortic valve replacement (AVR). Transcatheter aortic valve implantation (TAVI), either through a transfemoral or transapical approach, has become a potential option for these high-risk patients. Although TAVI technology will continue to be developed and perfected, most studies at this time reveal that symptoms are improved and that 1-year morbidity and mortality are similar to those for open surgical AVR. Anesthetic management for patients undergoing TAVI involves maintaining hemodynamic stability during periods of rapidly changing conditions and providing echocardiographic guidance and assessment. Postoperative care includes a variety of challenges such as managing pain control, monitoring for potential complications, and providing hemodynamic management.

The effect of the intrathoracic pressure regulator on hemodynamics and cardiac output.

The intrathoracic pressure regulator (ITPR) (CirQLator; Advanced Circulatory Systems Inc, Roseville, Minn) is a novel, noninvasive device intended to increase cardiac output and blood pressure in hypovolemic or cardiogenic shock by generating a continuous low-level intrathoracic vacuum in between positive pressure ventilations. Although there are robust data supporting the benefit of the ITPR in multiple animal models of shock, the device has not been used in humans. The goals of this study were to evaluate both the safety and efficacy of the ITPR in humans. Twenty patients undergoing coronary artery bypass graft surgery were enrolled in this phase 1 study. Intraoperative use of both pulmonary artery pressure monitoring and transesophageal echocardiography (TEE) was required for study inclusion. Hemodynamic variables as well as TEE measurements of left ventricular performance were collected at baseline and after the ITPR device was activated, before surgical incision. Thermodilution cardiac output increased significantly with the application of the ITPR (4.9 vs. 5.5 L/min; P = 0.017). Similarly, cardiac output was measured by TEE (5.1 vs. 5.7 L/min; P = 0.001). There were significant increases in pulmonary artery systolic blood pressures (35 vs. 38 mmHg; P < 0.001) and mean pulmonary artery pressures (24 vs. 26 mmHg; P = 0.008). There were no significant differences in systemic blood pressures, left ventricular volumes, stroke volume, or ejection fraction as measured by TEE. Using two different measurement techniques, application of the ITPR increased cardiac output in normovolemic anesthetized patients who underwent coronary artery bypass graft before sternotomy. These data suggest that the ITPR has the potential to safely and effectively increase cardiac output in humans.

The current status of off-pump coronary bypass surgery.

Purpose of review Coronary artery disease is the leading cause of the death in the Western world. Almost 500 000 coronary artery bypass (CABG) surgeries are performed in the USA annually. In the last 20 years, interest has increased in performing CABG without the use of cardiopulmonary bypass (CPB), to reduce postoperative complications associated with the use of CPB and aortic manipulation. Still, only about 20% of all CABG surgeries are performed off-pump and it is still debatable whether off-pump CABG has decreased postoperative morbidity and mortality compared to conventional CABG surgery. Recent findings Off-pump CABG is associated with less blood loss and need for transfusion, less postoperative atrial fibrillation, less stroke and probably less renal dysfunction. It is also associated with shorter postoperative intubation time and hospital length of stay. However, conventional CABG is associated with more complete revascularization and better graft patency rate. Summary Both off-pump and on-pump CABG have an excellent safety profile with very low morbidity and mortality. It seems that off-pump CABG is associated with reduced short-term postoperative morbidity; however, graft patency rate is higher and long-term mortality may be lower after on-pump CABG. Patient selection criteria and surgical skills are at least as important as the decision about the surgical technique.

Anesthesia for Esophageal Surgery

Patients presenting for esophageal surgery frequently have comorbidities including cardiopulmonary disease which should be evaluated per published ACC/AHA guidelines. Particular attention should be paid to symptoms and signs of esophageal obstruction, gastroesophageal reflux disease (GERD), and malnutrition which may affect the risk of perioperative complications. Postoperative pain control strategies are dictated by the surgical approach to the esophagus. Use of thoracic epidural analgesia in patients undergoing transthoracic esophageal surgery provides optimal pain control, permits early patient extubation and mobilization, and may improve outcomes. Patients presenting for esophageal surgery commonly have pathology which increases their risk of regurgitation and aspiration. This is particularly true for patients with achalasia and other motor disorders of the esophagus, patients with high-grade esophageal obstruction, and those with severe GERD. Consideration should be given to pharmacologic prophylaxis, awake or rapid sequence induction in a head-up position, and appropriate postoperative care, including gastric drainage. Excessive perioperative intravenous fluid administration, especially crystalloid, may lead to exaggerated fluid shifts toward the interstitial space causing increased complications such as poor wound healing, slower return of GI function, abdominal compartment syndrome, impaired anastomotic healing, increased cardiac demand, pneumonia, and respiratory failure. The ideal fluid regimen for major esophageal surgery should be individualized, optimizing cardiac output and oxygen delivery while avoiding excessive fluid administration. Patients presenting for emergent repair of esophageal disruption, rupture or perforation may present with hypovolemia, sepsis, and shock. Anesthetic management strategies should be based on the severity of these presenting conditions and the nature of the planned procedure. Esophageal anastomotic leak is a frequent complication associated with high morbidity and mortality and is likely to be a function of numerous surgical, systemic, and possibly anesthetic factors. Since anastomotic integrity is dependent upon adequate blood flow and oxygen delivery, the development of anastomotic leak may be related to intraoperative management variables, particularly systemic blood pressure, cardiac output, and oxygen delivery and may thus be modifiable by anesthetic management.

Driving Performance of Residents after Six Consecutive Overnight Work Shifts

Background:Residency training requires work in clinical settings for extended periods of time, resulting in altered sleep patterns, sleep deprivation, and potentially deleterious effects on safe performance of daily activities, including driving a motor vehicle. Methods:Twenty-nine anesthesiology resident physicians in postgraduate year 2 to 4 drove for 55 min in the Virginia Driving Safety Laboratory using the Driver Guidance System (MBFARR, LLC, USA). Two driving simulator sessions were conducted, one experimental session immediately after the final shift of six consecutive night shifts and one control session at the beginning of a normal day shift (not after call). Both sessions were conducted at 8:00 AM. Psychomotor vigilance task testing was employed to evaluate reaction time and lapses in attention. Results:After six consecutive night shifts, residents experienced significantly impaired control of all the driving variables including speed, lane position, throttle, and steering. They were also more likely to be involved in collisions. After six consecutive night shifts, residents had a significant increase in reaction times (281.1 vs. 298.5 ms; P = 0.001) and had a significant increase in the number of both minor (0.85 vs. 1.88; P = 0.01) and major lapses (0.00 vs. 0.31; P = 0.008) in attention. Conclusions:Resident physicians have greater difficulty controlling speed and driving performance in the driving simulator after six consecutive night shifts. Reaction times are also increased with emphasis on increases in minor and major lapses in attention after six consecutive night shifts.

Relationship Between Plethysmographic Waveform Changes and Hemodynamic Variables in Anesthetized, Mechanically Ventilated Patients Undergoing Continuous Cardiac Output Monitoring

OBJECTIVE To assess the relation between photoplethysmographically-derived parameters and invasively-determined hemodynamic variables. DESIGN After induction of anesthesia and placement of a Swan-Ganz CCOmbo catheter, a Nonin OEM III probe was placed on each patients earlobe. Photoplethysmographic signals were recorded in conjunction with cardiac output. Photoplethysmographic metrics (amplitude of absorbance waveform, maximal slope of absorbance waveform, area under the curve, and width) were calculated offline and compared with invasively determined hemodynamic variables. Subject-specific associations between each dependent and independent variable pair were summarized on a per-subject basis by the nonparametric Spearman rank correlation coefficient. The bias-corrected accelerated bootstrap resampling procedure of Efron and Tibshirani was used to obtain a 95% confidence interval for the median subject-specific correlation coefficient, and Wilcoxon sign-rank tests were conducted to test the null hypothesis that the median of the subject-specific correlation coefficients were equal to 0. SETTING University hospital. PARTICIPANTS Eighteen patients undergoing coronary artery bypass graft surgery. INTERVENTIONS Placement of a Swan-Ganz CCOmbo catheter and a Nonin OEM III pulse oximetry probe. MEASUREMENTS AND MAIN RESULTS There was a positive, statistically significant correlation between stroke volume and width (median correlation coefficient, 0.29; confidence interval, 0.01-0.46; p = 0.034). The concordance between changes in stroke volume and changes in width was 53%. No other correlations achieved statistical significance. CONCLUSIONS This study was unable to reproduce the results of prior studies. Only stroke volume and photoplethysmographic width were correlated in this study; however, the correlation and concordance (based on analysis of a 4-quadrant plot) were too weak to be clinically useful. Future studies in patients undergoing low-to-moderate risk surgery may result in improved correlations and clinical utility.

Perioperative morbidity: lessons from recent clinical trials.

Purpose of reviewTo identify the recent literature supporting the ability of anesthesiologists to impact morbidity and mortality outside of the immediate intraoperative period. Recent findingsHemodynamic management designed to optimize cardiac output and stroke volume can significantly lower the risk of perioperative morbidity, and, in some cases, mortality. The implications of the POISE trial, which upended the previously accumulating data in support of indiscriminate perioperative &bgr;-blockade by demonstrating worsened outcomes, were supported by high-quality, propensity-matched, prospectively collected data. Data supporting the safety of colloid use has been threatened by the retraction of 88 publications of a single author, as well as prospective, nonrandomized data, suggesting increased renal morbidity in critically ill patients receiving synthetic colloids. Large datasets continue to suggest an association between red blood cell transfusion and mortality. Analysis of the operating room strongly implicates anesthesia providers as a potential mechanism for bacterial contamination. SummaryAnesthesiologists should consider implication of goal-directed therapy in high-risk surgical patients, adhere to the American College of Cardiology/American Heart Association guidelines with regard to perioperative &bgr;-blockade, critically assess the data to support their choice of synthetic colloids over crystalloids, explore all possible strategies for avoiding perioperative transfusion, and be cognizant of their potential contribution to perioperative infectious morbidity.