Sevoflurane and Isoflurane-Pharmacokinetics, Hemodynamic Stability, and Cardioprotective Effects During Cardiopulmonary Bypass.

OBJECTIVES: This study aimed to evaluate the pharmacokinetic profiles of sevoflurane and isoflurane during use of minimized extracorporeal circulation to perform coronary artery bypass graft surgery. Furthermore, cardiovascular stability during bypass and the postoperative release of troponins were evaluated. DESIGN: Prospective, randomized study. SETTING: University hospital. PARTICIPANTS: The study comprised 31 adult patients undergoing coronary artery bypass grafting. INTERVENTIONS: The pharmacokinetic measurements of the concentration of the volatile anesthetics in the arterial and venous blood, air inlet, air outlet, and gas exhaust of the extracorporeal circulation were recorded. Secondary end-points were cardiovascular stability during bypass, amount of postoperative release of troponin, time to extubation, time to discharge from the intensive care unit and the hospital, and 30-day mortality. MEASUREMENTS AND MAIN RESULTS: Thirty patients completed the protocol. The pharmacokinetics of isoflurane and sevoflurane were almost identical, with a rapid wash-in (time to reach 50% of arterial steady state) concentration of 0.87±0.97 minutes and 1.14±0.35 minutes for isoflurane and sevoflurane, respectively, and a biphasic venous elimination with a terminal half-life of approximately 10 minutes for both compounds. There was a correlation between the gas inlet and the gas exhaust of the extracorporeal circulation. No difference in cardiovascular stability was found. High-sensitivity troponin concentrations on the first postoperative morning were 0.355±0.312 µg/mL and 0.225±0.111 µg/mL in the isoflurane and sevoflurane groups, respectively (p = 0.147). CONCLUSIONS: The study found similar pharmacokinetics regarding wash-in and wash-out for sevoflurane and isoflurane. In addition, no difference in cardiovascular stability was found. The markers of cardiac damage were not different between the two anesthetics. Based on these data, sevoflurane and isoflurane might be used equivalently in patients undergoing coronary artery bypass graft surgery with extracorporeal circulation.

Phenylephrine infusion for spinal-induced hypotension in elective cesarean delivery: Does preload make a difference?

BACKGROUND AND AIMS: Patients undergoing elective cesarean delivery (CD) have a high-risk of spinal-induced hypotension (SIH). We hypothesized that a colloid preload would further reduce SIH when compared with a crystalloid preload. MATERIAL AND METHODS: Eighty-two healthy parturients undergoing elective CD were included in the study. Patients were randomly assigned to two groups (41 patients in each group) to receive either Lactated Ringer's solution (1500 ml) or hydroxyethyl starch (6% in normal saline, 500 ml) 30 min prior to placement of spinal anesthesia. All patients were treated with a phenylephrine infusion (100 mcg/min), titrated during the study. RESULTS: There was no statistical difference between groups with regards to the incidence of hypotension (10.8% in the colloid group vs. 27.0% in the crystalloid group, P = 0.12). There was also no difference between groups with respect to bradycardia, APGAR scores, and nausea and vomiting. Significantly less phenylephrine (1077.5 ± 514 mcg) was used in the colloid group than the crystalloid group (1477 ± 591 mcg, P = 0.003). CONCLUSION: The preload with 6% of hydroxyethyl starch before CD might be beneficial for the prevention of SIH.

Effect of cold perfusion and perfluorocarbons on liver graft ischemia in a donation after cardiac death model.

BACKGROUND: Effects of two perfluorocarbon (PFC) formulations (perfluorodecalin emulsion and perfluorodecalin liquid) on the quality of liver graft preservation, in a donation after cardiac death (DCD) rat model, were investigated. The significance of continuous graft perfusion during cold preservation was also explored. MATERIALS AND METHODS: DCD model: 30 min after cardiopulmonary arrest was initiated, livers were excised and flushed with cold University of Wisconsin (UW) solution (± PFC) and preserved in the same solution for 8 h. The study groups were preserved as follows: group 1: no perfusion; group 2: perfusion with UW; group 3: PFC was administered before cardiac arrest and the liver was perfused with UW alone; and groups 4 and 5: perfused with UW + 1 of two PFCs. In a baseline group used only for comparison of gene expression, livers were quick-frozen after cardiac arrest. Microarrays were used to analyze liver messenger RNA transcripts. Histopathologic, immunohistochemical, and ADP/ATP ratio evaluations were performed to assess the quality of graft preservation. RESULTS: Significant decreases in downregulation and increases in upregulation of hepatic genes (relative to baseline) were demonstrated in all perfusion groups. This trend was most pronounced in the PFC groups. Lower fat content and ADP/ATP ratio and a reduction in Caspase 3 activation were found in all perfusion groups. CONCLUSION: Hypothermic perfusion of rat DCD liver grafts with oxygenated UW solution (± PFC) produced superior preservation compared with nonperfusion storage. The observed changes in expression of hepatic genes may represent a protective effect in the DCD model.

Use of a third-generation perfluorocarbon for preservation of rat DCD liver grafts.

BACKGROUND: Cold storage in any of the commonly used preservation solutions is not always adequate for donation after cardiac death (DCD) liver grafts due to prolonged warm ischemic time. In this study, we used a third-generation perfluorocarbon (PFC), Oxycyte, for DCD liver graft preservation in a rat model. MATERIALS AND METHODS: Twenty-eight rats (14 in each group) were used. Thirty minutes after cardiopulmonary arrest, livers were harvested and flushed with a cold and pre-oxygenated solution of either University of Wisconsin (UW) or UW + 20% PFC. After 8 h of cold preservation in either of the investigated solutions, liver graft specimens were analyzed for evidence of ischemic injury. Hemotoxylin and eosin staining (H and E), as well as immunohistochemical analysis with anti-cleaved caspase 3 antibody, was performed. Levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in the preservation solution were analyzed at 1 and 8 h during preservation. RESULTS: In the PFC group, the degree of cell congestion, vacuolization and necrosis were all significantly less than in the UW group (P = 0.002-0.004). The number of cells with a positive cleaved caspase 3 antibody reaction was reduced by about 50% in comparison with the UW group (P < 0.006). The AST level in the PFC group was significantly less than in the UW group after 8 h of preservation (P < 0.048). CONCLUSION: The addition of PFC to UW solution significantly decreases the degree of histologic damage in rat DCD liver grafts. This preservation strategy can be potentially helpful for organ preservation after prolonged warm ischemia.

Successful Implementation of a Robust Medical Student Curriculum in Anesthesiology.

Increasing medical student enrollment creates challenges for clinical course directors to accommodate students and to provide consistency in clinical experiences. We discuss curricular modifications addressing these challenges specific to anesthesiology electives through the creation of 2-week anesthesiology electives to provide scheduling flexibility in the clinical years. We also incorporated curricular enhancements as a consistent didactic framework congruent with the clinical experience. Since initiating these electives in 2017, annual student enrollment increased >33%. More fourth-year students have enrolled in these courses. The annual number of students matching anesthesiology has maintained ≥8% graduating class. Our highest has been 15% in 2020.

Analgesic efficacy of ketamine and magnesium after laparoscopic sleeve gastrectomy: A randomized, double-blind, placebo-controlled trial.

Background Ketamine and magnesium are antagonists of the N-methyl-d-aspartate receptor, and are valuable adjuvants for multimodal analgesia and opioid sparing. Data are limited regarding the opioid sparing efficacy of the combined intraoperative application of these agents in laparoscopic bariatric surgery. The objective of this study was to compare the postoperative opioid sparing properties of a single intraoperative dose of ketamine versus a combination of single doses of ketamine and magnesium after laparoscopic gastric sleeve resection in bariatric patients. Methods One hundred and twenty- six patients were randomly assigned to receive single boluses of ketamine alone 0.5 mg kg-1 IV (ketamine group); combined ketamine bolus of 0.5 mg kg-1 IV and magnesium 2 g IV (ketamine and magnesium group); or placebo. Opioid consumption at 24 h (in morphine equivalents); pain at rest; postoperative nausea and vomiting impact score; sedation scores; and trends of transcutaneous carbon-di-oxide values were analysed. Results The median (inter-quartile range [range]) morphine consumption at 24 h were 32 (24-47 [4.8-91]) mg in the ketamine group, 37 (18-53 [1-144]) mg in the ketamine and magnesium group, and 26 (21-36 [5-89]) mg in the control group and were not significantly different between the groups. There were no differences for all other outcomes examined. Conclusion Combined single intraoperative bolus doses of ketamine and magnesium did not result in postoperative opioid sparing after laparoscopic gastric sleeve resection.

Case report: massive blood transfusion in a patient with immunoglobulin a deficiency undergoing cesarean delivery.

Patients with immunoglobulin (Ig)A deficiency develop autoantibodies against IgA, which render them vulnerable to severe anaphylactic reactions when transfused with conventional blood or blood products containing IgA. In this report, we describe a patient with IgA deficiency and placenta accreta undergoing emergency cesarean delivery who required massive blood transfusion. We discuss the workup and treatment options in patients with known IgA deficiency.

A Multidisciplinary Approach to Expedite Surgical Hip Fracture Care.

INTRODUCTION: In 2014, we implemented a geriatric hip fracture patient care pathway at our institution which was designed to improve outcomes and decrease time to surgery. MATERIALS AND METHODS: We analyzed retrospective data from 463 patients, aged greater than 50, who had surgical treatment for a closed hip fracture due to a low-energy injury between 2013 and 2016 at an academic institution. Objective outcome measures included time to surgery, mortality rate, and total hospital length of stay. Our primary goal was to decrease the time to surgery for definitive fracture fixation to within 24 hours of admission to the hospital for patients who were medically fit for surgery. RESULTS: We implemented a multidisciplinary, collaborative approach to address the needs of this specific patient population. Prior to implementing the pathway in 2013, our baseline time to surgery within 24 hours was 74.67%. After implementation, we had incremental yearly increases in the percentage of patients operated on within 24 hours, 82.31% in 2014 (P = .10) and 84.14% in 2015 (P = .04). During the study period, our overall time to surgery was reduced by 27% with an initial average of 20.22 hours in 2013, decreasing to 15.33 hours in 2014, and 14.63 hours in 2015. Our mortality rate at 1 year was 16% in 2013, 17% in 2014, and 15% in 2015. CONCLUSION: With implementation of the pathway, we were able to expedite surgical care for our patients and demonstrate a 10% improvement in the percentage of patients able to have surgery within 24 hours over a 3-year period. Our mortality and hospital length of stay, however, remained the same. Through this collaborative process and system standardization, we believe we have significantly improved not only direct patient care but their overall hospital experience. We continue to make improvements in our pathway.

Angiotensin axis blockade, acute kidney injury, and perioperative morbidity in patients undergoing colorectal surgery: A retrospective cohort study.

Patients undergoing surgery and taking angiotensin converting enzyme inhibitors (ACEi) or angiotensin receptor blockers (ARB) are susceptible to complications related to intraoperative hypotension. Perioperative continuation of such medications in patients undergoing colorectal surgery may be associated with more harm than benefit, as these patients are often exposed to other risk factors which may contribute to intraoperative hypotension. Our objectives were to assess the incidence and severity of postinduction hypotension as well as the rates of acute kidney injury (AKI), 30-day all-cause mortality, 30-day readmission, and hospital length of stay in adult patients undergoing colorectal surgery who take ACEi/ARB.We performed a retrospective chart review of patients undergoing colorectal surgery of ≥4 hour duration at a tertiary care academic medical center between January 2011 and November 2016. The preoperative and intraoperative characteristics as well as postoperative outcomes were compared between patients taking ACEi/ARB and patients not taking these medications.Of the 1020 patients meeting inclusion criteria, 174 (17%) were taking either ACEi or ARB before surgery. Patients taking these medications were more likely to receive both postinduction and intraoperative phenylephrine and ephedrine. The incidences of postoperative AKI (P = .35), 30-day all-cause mortality (P = .36), 30-day hospital readmission (P = .45), and hospital length of stay (P = .25), were not significantly different between the 2 groups.Our results support the current recommendation that ACEi/ARB use is probably safe within the colorectal surgery population during the perioperative period. Intraoperative hypotension should be expected and treated with vasopressors.

A randomized controlled trial comparing methohexital and propofol for induction in patients receiving angiotensin axis blockade.

BACKGROUND: Pharmacologic angiotensin axis blockade (AAB) has been associated with profound hypotension following anesthetic induction with propofol. To combat this problem, investigators have attempted to withhold angiotensin-converting enzyme inhibitors (ACEi) and angiotensin receptor blockers (ARB) preoperatively, or evaluated the effects of different induction agents in conferring greater hemodynamic stability. To date, methohexital has not been compared with the most commonly used induction agent, propofol. Hence, the primary objective was to study the hypothesis that methohexital confers a better hemodynamic profile than propofol for anesthetic induction, in patients receiving AAB. The secondary objective was to investigate the postinduction levels of serum neurohormones in an attempt to explain the mechanisms involved. METHODS: Forty-five adult, hypertensive patients taking ACEi or ARB and scheduled for elective, noncardiac surgery completed the study. Patients were randomized to receive equi-anesthetic doses of either propofol or methohexital for anesthetic induction. Hemodynamic variables were measured and blood samples were drawn before induction and for 15 minutes afterwards. RESULTS: Methohexital resulted in less hypotension compared with propofol (P = .01), although the degree of refractory hypotension was similar (P = .37). The postinduction systolic blood pressure (P = .03), diastolic blood pressure (P < .001) and heart rate (P = .03) were significantly higher in the methohexital group. A nonsignificant elevation of serum norepinephrine and epinephrine levels was observed in the methohexital group, while serum arginine vasopressin and angiotensin II levels did not differ between groups. CONCLUSION: While methohexital was shown to confer greater hemodynamic stability in patients taking ACEi/ARB, the measured hormone levels could not explain the mechanism for this effect.