Perioperative Anesthetic and Transfusion Management of Veno-Venous Extracorporeal Membrane Oxygenation Patients Undergoing Noncardiac Surgery: A Case Series of 21 Procedures.

OBJECTIVES: To analyze the perioperative management of veno-venous extracorporeal membrane oxygenation (VV ECMO) in patients undergoing major noncardiac surgical procedures, which is poorly described in the literature. In doing so, perioperative challenges related to hemodynamic instability, impaired gas exchange, bleeding, and coagulopathy will be quantified. DESIGN: Retrospective, nonrandomized, observational study. SETTING: A single, university-affiliated, quaternary medical center. PARTICIPANTS: Fourteen patients who underwent 21 noncardiac surgical procedures during the period of January 1, 2014, through April 1, 2016. Approval for this study was obtained from the Duke University Medical Center Institutional Review Board (study Pro00072723). INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Fifty percent of subjects were alive at 1 year after ECMO cannulation. Anesthetic type was variable with an inhaled anesthetic utilized in 71.4% of events, a presurgical continuous sedative was continued in 81.0% of cases, fentanyl was utilized in 100% of encounters, and midazolam was utilized in 71.4% of encounters. Intraoperatively, 50% of encounters resulted in an oxygen desaturation with a peripheral oxygen saturation assessed by pulse oximetry (SpO2)<90%, and 15% of procedures resulted in a SpO2 <80%. A vasopressor, most commonly epinephrine, was used during 66.7% of procedures. Intraoperatively, blood was administered in 52.4% of procedures, fresh frozen plasma was administered in 23.8% of procedures, and platelets were administered in 28.6% of procedures. Hemoglobin levels remained stable throughout the perioperative period, averaging 9.5 g/dL preoperatively, 9.7 g/dL immediately postoperatively, and 9.5 g/dL 24 hours after surgery. CONCLUSIONS: VV ECMO patients can be anesthetized using either inhalational or intravenous anesthetics. Patient hemodynamics, oxygenation, and decarboxylation require frequent interventions, but can typically be optimized to meet clinically acceptable thresholds.

Renal Angina Is a Sensitive, but Nonspecific Identifier of Postcardiac Surgery Acute Kidney Injury.

OBJECTIVES: Acute kidney injury (AKI) is a common complication of cardiac surgery, and early detection is difficult. This study was performed to determine the sensitivity, specificity, positive predictive value, negative predictive value, and statistical performance of renal angina (RA) as an early predictor of AKI in an adult cardiac surgical patient population. DESIGN: Retrospective, nonrandomized, observational study. SETTING: A single, university-affiliated, quaternary medical center. PARTICIPANTS: The study comprised 324 consecutive patients undergoing coronary artery bypass grafting or cardiac valvular surgery from February 1 through July 30, 2014. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: One hundred-seven patients at moderate or high risk of developing postoperative renal injury were identified, 82 of whom met criteria for RA. The occurrence of RA was found to have an 80.9% sensitivity and 30.8% specificity for the prediction of AKI using Acute Kidney Injury Network criteria and 89.3% sensitivity and 27.8% specificity when paired with the Risk, Injury, Failure, Loss, End Stage Renal Disease criteria. A receiver operating characteristic area under the curve analysis revealed a nonsignificant predictive ability of 55.8% (95% confidence interval 0.47-0.65) when RA was paired with Acute Kidney Injury Network criteria; however, the receiver operating characteristic area under the curve was significant when paired with Risk, Injury, Failure, Loss, End Stage Renal Disease criteria, with a predictive ability of 0.586 (0.509-0.662). CONCLUSIONS: RA is a sensitive, but nonspecific, predictor of postcardiac surgery AKI, with clinical utility most suited as a screening tool.

Perioperative Management of the Adult Patient on Venovenous Extracorporeal Membrane Oxygenation Requiring Noncardiac Surgery.

The use of venovenous extracorporeal membrane oxygenation is increasing worldwide. These patients often require noncardiac surgery. In the perioperative period, preoperative assessment, patient transport, choice of anesthetic type, drug dosing, patient monitoring, and intraoperative and postoperative management of common patient problems will be impacted. Furthermore, common monitoring techniques will have unique limitations. Importantly, patients on venovenous extracorporeal membrane oxygenation remain subject to hypoxemia, hypercarbia, and acidemia in the perioperative setting despite extracorporeal support. Treatments of these conditions often require both manipulation of extracorporeal membrane oxygenation settings and physiologic interventions. Perioperative management of anticoagulation, as well as thresholds to transfuse blood products, remain highly controversial and must take into account the specific procedure, extracorporeal membrane oxygenation circuit function, and patient comorbidities. We will review the physiologic management of the patient requiring surgery while on venovenous extracorporeal membrane oxygenation.

Management of Sedation and Paralysis.

Sedatives are administered to decrease patient discomfort and agitation during mechanical ventilation and to maintain patient-ventilator synchrony. Titration of infusions and or bolus dosing to maintain light sedation goals according to validated scales is recommended. However, it is important to consider deeper sedation for patients with refractory patient-ventilator dyssynchrony (PVD) to prevent volutrauma and barotrauma. Deep sedation plus muscle relaxants may be required to treat PVD or to reduce oxygen consumption and carbon dioxide production. Although minimization and protocolization of sedation in the intensive care unit improves costs and outcomes, it is important to consider goals on an individual basis.

The role of intraoperative transesophageal echocardiographic monitoring in a patient with hypertrophic cardiomyopathy undergoing laparoscopic surgery.

Hypertrophic cardiomyopathy (HCM) presents a significant perioperative challenge. Anesthetic drugs, patient positioning, and surgical technique can provoke worsening left ventricular outflow tract obstruction and hemodynamic deterioration. In this case report, we present the perioperative management of a 70-year-old male with a history of HCM who underwent a robotic laparoscopic prostatectomy. Discussion focuses on the utilization of echocardiographic guidance in the care of patients with HCM undergoing noncardiac surgery, as well as the pathophysiology of laparoscopic insufflation and its effects on left ventricular outflow tract obstruction in HCM.

Intraoperative transesophageal echocardiography to evaluate acute cessation of venous inflow during cardiopulmonary bypass.

Acute disruption of venous return during cardiopulmonary bypass (CPB) may be due to malposition of the venous cannula, kinks or obstruction of the venous tubing by a smaller cannula, airlock, or mechanical disruption of blood flow. We describe an acute obstruction of the venous cannula by blood clots that were visualized on the transesophageal echocardiogram during CPB. Appropriate measures were taken by the surgeon to evacuate the clot and restore CPB. The clots were not seen on the transesophageal echocardiogram before CPB raising suspicion that they originated in a lower extremity and migrated to the right atrium resulting in venous cannula obstruction.

Lymph node ratio is an important and independent prognostic factor for patients with stage III melanoma.

INTRODUCTION: The incidence of melanoma is dramatically increasing worldwide. We hypothesized that the ratio of metastatic to examined lymph node ratio (LNR) would be the most important prognostic factor for stage III patients. METHODS: We retrospectively reviewed our institutional database of melanoma patients and identified 168 patients who underwent lymph node dissection (LND) for stage III disease between 1993 and 2007. Patients were divided into three groups based on LNR (≤10%, n = 93; 10-≤25%, n = 45; and >25%, n = 30). Univariate and multivariate analysis was performed using Cox proportional hazards model. RESULTS: The median survival time of the entire group of patients was 34 months. The median number of positive nodes was 2 (range = 1, 55), and the median number of examined nodes was 22 (range = 5-123). Tumor characteristics of the primary melanoma (such as thickness, ulceration, and primary site) were not significant predictors of survival in this analysis. By univariate analysis, LNR was an important prognostic factor. Patients with LNR 10-25% and >25% had decreased survival compared to those patients with LNR ≤10% (HR = hazard ratio = 2.0 and 3.1, respectively; P ≤ 0.005). The number of positive lymph nodes also impacted on survival (P = 0.001). In multivariate analysis, LNR of 10-25% and >25% predicted survival (HR = 2.5 and 4.0, respectively). CONCLUSION: LNR is an important prognostic factor in patients undergoing LND for stage III melanoma. It can be used to stratify patients being considered for adjuvant therapy trials and should be evaluated using a larger prospective database.

In vivo oxygen consumption and hemoglobin levels in human thyroarytenoid muscle.

OBJECTIVES/HYPOTHESIS: Visible light spectroscopy (VLS) is the technology behind the Food and Drug Administration-approved TSTAT device that is used to monitor tissue oxygen (StO(2)) and relative total hemoglobin (rtHb) levels by measuring reflected visible light. The purpose of this novel, pilot study was to determine if VLS is a reliable and valid method of measuring StO(2) and rtHb levels in the human thyroarytenoid/lateral cricoarytenoid (TA-LCA) muscle complex, thus providing information about vocal fold muscle physiology. STUDY DESIGN: Pre-test/post-test with mulitple baselines and two conditions. METHODS: VLS measurements were taken at baseline, during exercise, and following recovery on six subjects using both noncontact channel-port endoscope (endo-probe) and laryngeal electromyography (LEMG) needle-guided techniques. RESULTS: The average baseline StO(2) was 69% (standard deviation [SD] = 3.6%) for the LEMG-guided probe and was 71.5% (SD = 2.8%) for the endo-probe. During phonation, the StO(2) for the LEMG-guided probe dropped to 59% (SD = 7%; P = .04). Mean rtHb measured by the LEMG probe rose from a baseline of 144 µM (SD = 165 µM) to 214 µM (SD = 166 µM, P = .34) during phonation and back to 149 µM (SD = 139 µM, P = .85) after recovery. Mean rtHb as measured using the endo-probe at baseline and after recovery was 104 µM (SD = 30 µM, P = .76). CONCLUSIONS: VLS can be used to measure changes in StO(2) and rtHb levels pre- and postexercise in the human TA-LCA muscle complex.