Aortic Valve Thrombosis after Valve-Sparing Aortic Root Replacement and Insertion of an Extracorporeal Left Ventricular Assist Device, Masked by Mediastinal Packing.

Aortic valve (AV) or aortic root thrombus related to a left ventricular assist device (LVAD) is a relatively uncommon but potentially life-threatening complication. In the present report, we describe a complex case where echocardiographic diagnosis of AV thrombosis was obscured by the presence of mediastinal packing in a patient who underwent valve-sparing aortic root replacement and insertion of the CentriMag™ LVAD for postcardiotomy cardiogenic shock. A large AV thrombus may develop rapidly in patients with LVADs. This case highlights the importance of a careful and thorough transesophageal echocardiography examination in detecting this complication and in altering surgical management.

Anesthetic Considerations for Pneumonectomy With Left Atrial Resection on Cardiopulmonary Bypass in a Patient With Lung Cancer: A Case Report.

Cases of pneumonectomy plus atrial resection for lung cancer have been reported in the surgical literature, but not the anesthesia literature. To achieve curative resection, cardiopulmonary bypass (CPB) may be necessary. Although CPB may complicate the management of these high-risk patients, these cases should always be undertaken in a center where it is immediately available. Here, we discuss the anesthetic management of a 70-year-old man with left lower lobe lung cancer invading the left inferior pulmonary vein and left atrium.

Subnormothermic ex vivo liver perfusion reduces endothelial cell and bile duct injury after donation after cardiac death pig liver transplantation.

An ischemic-type biliary stricture (ITBS) is a common feature after liver transplantation using donation after cardiac death (DCD) grafts. We compared sequential subnormothermic ex vivo liver perfusion (SNEVLP; 33°C) with cold storage (CS) for the prevention of ITBS in DCD liver grafts in pig liver transplantation (n = 5 for each group). Liver grafts were stored for 10 hours at 4°C (CS) or preserved with combined 7-hour CS and 3-hour SNEVLP. Parameters of hepatocyte [aspartate aminotransferase (AST), international normalized ratio (INR), factor V, and caspase 3 immunohistochemistry], endothelial cell (EC; CD31 immunohistochemistry and hyaluronic acid), and biliary injury and function [alkaline phosphatase (ALP), total bilirubin, and bile lactate dehydrogenase (LDH)] were determined. Long-term survival (7 days) after transplantation was similar between the SNEVLP and CS groups (60% versus 40%, P = 0.13). No difference was observed between SNEVLP- and CS-treated animals with respect to the peak of serum INR, factor V, or AST levels within 24 hours. CD31 staining 8 hours after transplantation demonstrated intact EC lining in SNEVLP-treated livers (7.3 × 10(-4) ± 2.6 × 10(-4) cells/µm(2)) but not in CS-treated livers (3.7 × 10(-4) ± 1.3 × 10(-4) cells/µm(2) , P = 0.03). Posttransplant SNEVLP animals had decreased serum ALP and serum bilirubin levels in comparison with CS animals. In addition, LDH in bile fluid was lower in SNEVLP pigs versus CS pigs (14 ± 10 versus 60 ± 18 µmol/L, P = 0.02). Bile duct histology revealed severe bile duct necrosis in 3 of 5 animals in the CS group but none in the SNEVLP group (P = 0.03). Sequential SNEVLP preservation of DCD grafts reduces bile duct and EC injury after liver transplantation.

Anesthetic management of a patient with arginase deficiency undergoing liver transplantation.

A 20-year-old female underwent orthotopic liver transplantation for arginase deficiency, a urea cycle disorder. A hyperammonemic state was prevented by the administration of lipid and carbohydrate substrate and avoidance of protein loading (including human albumin) and prolonged fasting. Caval cross-clamping may have been tolerated poorly owing to the potential interaction between hyperargininemia (a nitric oxide precursor) and the lack of collateral venous drainage. Ammonia and arginine levels improved in parallel with hepatic function after reperfusion of the hepatic graft.

Hyperchloremia after noncardiac surgery is independently associated with increased morbidity and mortality: a propensity-matched cohort study.

BACKGROUND: The use of normal saline is associated with hyperchloremic metabolic acidosis. In this study, we sought to determine the incidence of acute postoperative hyperchloremia (serum chloride >110 mEq/L) and whether this electrolyte disturbance is associated with an increase in length of hospital stay, morbidity, or 30-day postoperative mortality. METHODS: Data were retrospectively collected on consecutive adult patients (>18 years of age) who underwent inpatient, noncardiac, nontransplant surgery between January 1, 2003 and December 31, 2008. The impact of postoperative hyperchloremia on patient morbidity and length of hospital stay was examined using propensity-matched and logistic multivariable analysis. RESULTS: The dataset consisted of 22,851 surgical patients with normal preoperative serum chloride concentration and renal function. Acute postoperative hyperchloremia (serum chloride >110 mmol/L) is quite common, with an incidence of 22%. Patients were propensity-matched based on their likelihood to develop acute postoperative hyperchloremia. Of the 4955 patients with hyperchloremia after surgery, 4266 (85%) patients were matched to patients who had normal serum chloride levels after surgery. These 2 groups were well balanced with respect to all variables collected. The hyperchloremic group was at increased risk of mortality at 30 days postoperatively (3.0% vs 1.9%; odds ratio = 1.58; 95% confidence interval, 1.25-1.98) (relative risk 1.6 or risk increase of 1.1%) and had a longer hospital stay (7.0 days [interquartile range 4.1-12.3] compared with 6.3 [interquartile range 4.0-11.3]) than patients with normal postoperative serum chloride levels. Patients with postoperative hyperchloremia were more likely to have postoperative renal dysfunction. Using all preoperative variables and measured outcome variables in a logistic regression analysis, hyperchloremia remained an independent predictor of 30-day mortality with an odds ratio of 2.05 (95% confidence interval, 1.62-2.59). CONCLUSION: This retrospective cohort trial demonstrates an association between hyperchloremia and poor postoperative outcome. Additional studies are required to demonstrate a causal relationship between these variables.

The interaction of carbon dioxide and hypoxia in the control of cerebral blood flow.

Both hypoxia and carbon dioxide increase cerebral blood flow (CBF), and their effective interaction is currently thought to be additive. Our objective was to test this hypothesis. Eight healthy subjects breathed a series of progressively hypoxic gases at three levels of carbon dioxide. Middle cerebral artery velocity, as an index of CBF; partial pressures of carbon dioxide and oxygen and concentration of oxygen in arterial blood; and mean arterial blood pressure were monitored. The product of middle cerebral artery velocity and arterial concentration of oxygen was used as an index of cerebral oxygen delivery. Two-way repeated measures analyses of variance (rmANOVA) found a significant interaction of carbon dioxide and hypoxia factors for both CBF and cerebral oxygen delivery. Regression models using sigmoidal dependence on carbon dioxide and a rectangular hyperbolic dependence on hypoxia were fitted to the data to illustrate this interaction. We concluded that carbon dioxide and hypoxia act synergistically in their control of CBF so that the delivery of oxygen to the brain is enhanced during hypoxic hypercapnia and, although reduced during normoxic hypocapnia, can be restored to normal levels with progressive hypoxia.

End-inspiratory rebreathing reduces the end-tidal to arterial PCO2 gradient in mechanically ventilated pigs.

PURPOSE: Noninvasive monitoring of the arterial partial pressures of CO(2) (PaCO(2)) of critically ill patients by measuring their end-tidal partial pressures of CO(2) (PETCO(2)) would be of great clinical value. However, the gradient between PETCO(2) and PaCO(2) (PET-aCO(2)) in such patients typically varies over a wide range. A reduction of the PET-aCO(2) gradient can be achieved in spontaneously breathing healthy humans using an end-inspiratory rebreathing technique. We investigated whether this method would be effective in reducing the PET-aCO(2) gradient in a ventilated animal model. METHODS: Six anesthetized pigs were ventilated mechanically. End-tidal gases were systematically adjusted over a wide range of PETCO(2) (30-55 mmHg) and PETO(2) (35-500 mmHg) while employing the end-inspiratory rebreathing technique and measuring the PET-aCO(2) gradient. Duplicate arterial blood samples were taken for blood gas analysis at each set of gas tensions. RESULTS: PETCO(2) and PaCO(2) remained equal within the error of measurement at all gas tension combinations. The mean ± SD PET-aCO(2) gradient (0.13 ± 0.12 mmHg, 95% CI -0.36, 0.10) was the same (p = 0.66) as that between duplicate PaCO(2) measurements at all PETCO(2) and PETO(2) combinations (0.19 ± 0.06, 95% CI -0.32, -0.06). CONCLUSIONS: The end-inspiratory rebreathing technique is capable of reducing the PET-aCO(2) gradient sufficiently to make the noninvasive measurement of PETCO(2) a useful clinical surrogate for PaCO(2) over a wide range of PETCO(2) and PETO(2) combinations in mechanically ventilated pigs. Further studies in the presence of severe ventilation-perfusion (V/Q) mismatching will be required to identify the limitations of the method.

Frequent malpositions of peripherally inserted central venous catheters in patients undergoing head and neck surgery.

PURPOSE: Peripherally inserted central venous catheters (PICCs) do not interfere with surgical access during neck dissection and are used in patients undergoing head and neck surgery. However, severe complications associated with malpositioning of PICCs have been reported in these patients. We conducted a retrospective study to determine the incidence of aberrant positioning of PICCs in patients undergoing free flap reconstructive (FFR) surgery for head and neck malignancies. METHODS: We analyzed a database of 269 patients undergoing FFR surgery. After induction of general anesthesia, a PICC was inserted successfully in 130 patients (48%) at bedside without image guidance. A PICC was not used in 139 patients (52%). A chest x-ray was performed at admission to the postanesthetic care unit, stored digitally, and reviewed retrospectively by two independent observers. Based on the chest x-ray findings, the PICC position was classified as proper, suboptimal, or aberrant and defined according to the position of the PICC tip, i.e., proper, if situated in the ipsilateral innominate vein or in the superior vena cava; suboptimal, if situated in the subclavian vein; and aberrant, if situated in any other location. RESULTS: Proper, suboptimal, and aberrant PICC positions were found in 68 (52%), 17 (13%), and 45 (35%) patients, respectively. The proper position was confirmed more frequently with a left- than with a right-sided approach: 23/29 (79%) vs 45/101 (44%) patients, respectively (P < 0.001). CONCLUSIONS: There is a high incidence of aberrant positioning when PICCs are inserted without image guidance. The left-sided approach might be preferable due to a lower incidence of malpositions. The risk-benefit ratio should be estimated carefully before using a PICC in patients undergoing FFR procedures.

The effect of nasogastric tube application during cardiac surgery on postoperative nausea and vomiting--a randomized trial.

OBJECTIVE: Postoperative nausea and vomiting (PONV) are significant morbidities following cardiac surgery. The purpose of this study was to determine if application of a nasogastric (NG) tube during cardiac surgery can reduce the prevalence of postoperative PONV. DESIGN: This study was a prospective randomized controlled trial. SETTING: University tertiary referral center. PARTICIPANTS: Two hundred two patients undergoing elective cardiac procedures. INTERVENTIONS: Patients were prospectively enrolled and randomized to either receive or not receive an NG tube after induction of anesthesia. Standard anesthetic technique and postoperative care were employed in all patients. Preoperative demographic data, pain score, nausea score and incidence of vomiting were recorded early (0-8 hours) and late (8-16 hours) following extubation. Antiemetic and analgesic medications were compared between the 2 groups. MEASUREMENTS AND MAIN RESULTS: One hundred three patients were randomized to no an NG tube (controls) and 99 received an NG tube as part of their perioperative management. Demographic data and surgical characteristics were similar between the 2 groups. However, the control group had more smokers. Incidence and severity of nausea, pain scores, and analgesic requirements were similar between the 2 groups. Prevalence of vomiting was more frequent in the control group (24%) than in the NG tube group (10%, p = 0.007), and was more frequent in patients who underwent valve and redo procedures. CONCLUSIONS: Use of an NG tube during cardiac surgery may reduce the incidence of postoperative vomiting.

Isocapnic hyperpnoea shortens postanesthetic care unit stay after isoflurane anesthesia.

BACKGROUND: We conducted a prospective controlled clinical trial of the effect of isocapnic hyperpnoea (IH) on the times-to-recovery milestones in the operating room (OR) and postanesthetic care unit (PACU) after 1.5 to 3 hours of isoflurane anesthesia. METHODS: Thirty ASA grade I-III patients undergoing elective gynecological surgery were randomized at the end of surgery to either IH or the conventional recovery (control). Six patients with duration of anesthesia of <90 minutes were excluded from the analysis. The anesthesia protocol included propofol, fentanyl, morphine, rocuronium, and isoflurane in air/O(2). Unpaired t tests and analyses of variance were used to test for differences in times-to-recovery indicators between the two groups. RESULTS: The durations of anesthesia in IH and control groups were 140.8 + or - 32.7 and 142 + or - 55.6 minutes, respectively (P = 0.99). The time to extubation was much shorter in the IH group than in the control group (6.6 + or - 1.6 (SD) vs. 13. 6 + or - 3.9 minutes, respectively; P < 0.01). The IH group also had shorter times to eye opening (5.8 + or - 1.3 vs. 13.7 + or - 4.5 minutes; P < 0.01), eligibility for leaving the OR (8.0 + or - 1.7 vs. 17.4 + or - 6.1 minutes; P < 0.01), and eligibility for PACU discharge (74.0 + or - 16.5 vs. 94.5 + or - 14.7 minutes; P < 0.01). There were no differences in other indicators of recovery. CONCLUSION: IH accelerates recovery after 1.5 to 3 hours of isoflurane anesthesia and shortens OR and PACU stay.

Clinicopathologic and therapeutic risk factors for perioperative complications and prolonged hospital stay in free flap reconstruction of the head and neck.

BACKGROUND: We aimed to determine predictors of morbidity in patients undergoing microvascular free flap reconstruction of the head and neck. METHODS: We prospectively evaluated 796 cases between 1999 and 2007 using univariate and multivariate analysis to determine predictors of morbidity and prolonged hospital stay. RESULTS: Two hundred thirty-nine patients (30%) developed major complications. Age, body mass index (BMI), American Society of Anesthesiology (ASA) score, Kaplan Feinstein comorbidity index (KFI) score, preoperative hemoglobin, and tracheostomy were independent predictors of major complication. Predictors of prolonged hospital stay included age, recent weight loss, alcohol excess, ASA, KFI, preoperative hemoglobin, mucosal surgery, anesthesia duration, and crystalloid replacement volume. CONCLUSION: Several variables are associated with an increased risk of development of major complications following free flap reconstruction of the head and neck. Although many of these variables are irreversible, they aid risk stratification of patients undergoing free flap reconstruction, and assist clinicians in making treatment decisions, consenting, and providing patients with realistic expectations regarding their perioperative course.

Prevalence of claustrophobia and magnetic resonance imaging after coronary artery bypass graft surgery.

BACKGROUND: The purpose of this study was to determine the prevalence of claustrophobia in patients undergoing magnetic resonance imaging (MRI) after coronary artery bypass graft (CABG) surgery. METHODS: After IRB approval, we conducted a substudy of a prospective randomized controlled clinical trial of 311 patients evaluating administration of tranexamic acid and early saphenous vein graft patency with MRI after conventional CABG surgery. Chest tube drainage was measured at 6, 12, and 24 hours after surgery. The rate of transfusion and the amount of red blood cells (RBC), fresh frozen plasma (FFP), and platelets transfused were recorded. RESULTS: A total of 237(76%) patients underwent MRI after surgery. 39 (14%, [95% CI, 10.2 to 18.0]) patients experienced severe anxiety caused by a fear of enclosed space in the MRI coil necessitating termination of the procedure. Patients with claustrophobia were on average 5 years younger. They were more likely to have diabetes mellitus and hypertension. Patients with claustrophobia had increased chest tube drainage during the postoperative period. The rate of blood product transfusion was similar between the two groups but patients with claustrophobia who were transfused received significantly more RBC and FFP than patients without claustrophobia. CONCLUSIONS: Postoperative claustrophobia and anxiety, leading to inability to undergo MRI, may be more common than previously described.

Non-invasive prospective targeting of arterial P(CO2) in subjects at rest.

Accurate measurements of arterial P(CO(2)) (P(a,CO(2))) currently require blood sampling because the end-tidal P(CO(2)) (P(ET,CO(2))) of the expired gas often does not accurately reflect the mean alveolar P(CO(2)) and P(a,CO(2)). Differences between P(ET,CO(2)) and P(a,CO(2)) result from regional inhomogeneities in perfusion and gas exchange. We hypothesized that breathing via a sequential gas delivery circuit would reduce these inhomogeneities sufficiently to allow accurate prediction of P(a,CO(2)) from P(ET,CO(2)). We tested this hypothesis in five healthy middle-aged men by comparing their P(ET,CO(2)) values with P(a,CO(2)) values at various combinations of P(ET,CO(2)) (between 35 and 50 mmHg), P(O(2)) (between 70 and 300 mmHg), and breathing frequencies (f; between 6 and 24 breaths min(-1)). Once each individual was in a steady state, P(a,CO(2)) was collected in duplicate by consecutive blood samples to assess its repeatability. The difference between P(ET,CO(2)) and average P(a,CO(2)) was 0.5 +/- 1.7 mmHg (P = 0.53; 95% CI -2.8, 3.8 mmHg) whereas the mean difference between the two measurements of P(a,CO(2)) was -0.1 +/- 1.6 mmHg (95% CI -3.7, 2.6 mmHg). Repeated measures ANOVAs revealed no significant differences between P(ET,CO(2)) and P(a,CO(2)) over the ranges of P(O(2)), f and target P(ET,CO(2)). We conclude that when breathing via a sequential gas delivery circuit, P(ET,CO(2)) provides as accurate a measurement of P(a,CO(2)) as the actual analysis of arterial blood.

Accelerated recovery from sevoflurane anesthesia with isocapnic hyperpnoea.

BACKGROUND: Isocapnic hyperpnoea (IH) reduces recovery time from isoflurane anesthesia in animals and humans. We studied the effect of IH on the emergence profile of sevoflurane-anesthetized patients by comparing postoperative recovery variables in patients administered IH (IH group) to those recovered in the customary fashion (control group). METHODS: We enrolled 30 ASA I-III patients undergoing elective gynecological surgery. Induction and maintenance of anesthesia were standardized with a protocol consisting of fentanyl, propofol, rocuronium, and sevoflurane in air/O2. Patients were randomly assigned to control (C) or IH groups at the end of the surgery. We recorded time intervals from discontinuing sevoflurane to recovery milestones. RESULTS: Time to tracheal extubation was much shorter in the IH group compared with group C (6.2 +/- 2.1 vs 12.3 +/- 3.8 min, respectively, P < 0.01). The IH group also had shorter times to initiation of spontaneous ventilation (4.2 +/- 1.7 vs 6.5 +/- 3.8 min, P = 0.047), eye opening (5.5 +/- 1.4 vs 13.3 +/- 4.4 min, P < 0.01), bispectral index value >75 (3.9 +/- 1.1 vs 8.8 +/- 3.7 min, P < 0.01), leaving operating room (7.7 +/- 2.0 vs 15.3 +/- 3.4 min, P < 0.01), and eligibility for postanesthetic care unit discharge (67.2 +/- 19.3 vs 90.6 +/- 20.0 min, P < 0.01). CONCLUSION: IH accelerates recovery from sevoflurane anesthesia and shortens operating room and postanesthetic care unit stay.

Effects of alveolar recruitment on arterial oxygenation in patients after cardiac surgery: a prospective, randomized, controlled clinical trial.

OBJECTIVE: Pulmonary atelectasis and hypoxemia remain considerable problems after cardiac surgery. The objective of this study was to determine the efficacy of consecutive vital capacity maneuvers (C-VCMs) to improve oxygenation in patients after cardiac surgery. STUDY DESIGN: Randomized, controlled clinical trial. SETTING: Tertiary referral teaching center. PARTICIPANTS: Ninety-five patients requiring elective cardiac surgery with cardiopulmonary bypass (CPB). INTERVENTION: Patients were randomly allocated to either C-VCM or control groups. In the C-VCM group, lung inflation at pressure of 35 cmH(2)O was sustained for 15 seconds before separation from CPB and at 30 cmH(2)O for 5 seconds after admission to the intensive care unit (ICU). MEASUREMENTS AND MAIN RESULTS: The primary outcome was the ratio of arterial oxygen tension to inspired oxygen fraction measured at the following predetermined time intervals: after induction of anesthesia, 15 minutes after separation from CPB, after admission to the ICU, after 3 hours of positive-pressure ventilation, after extubation, and before ICU discharge. C-VCM resulted in better arterial oxygenation extending from the immediate postoperative period to approximately 24 hours after surgery at the time of ICU discharge. There were no significant adverse events related to C-VCM application. CONCLUSION: C-VCM is an effective method to reduce hypoxemia associated with the formation of atelectasis after cardiac surgery with CPB.

Assessing fluid-responsiveness by a standardized ventilatory maneuver: the respiratory systolic variation test.

Respiratory-induced changes in arterial blood pressure predict fluid responsiveness. However, the accuracy of these variables is affected by the preset tidal volume and by the early inspiratory increase in arterial blood pressure. We have therefore calculated the slope produced by the minimal systolic blood pressures (plotted against the respective airway pressures) during a ventilatory maneuver consisting of four incremental, successive, pressure-controlled breaths, termed the Respiratory Systolic Variation Test (RSVT). In 14 ventilated patients, after major vascular surgery, the slope of the RSVT decreased significantly after intravascular fluid administration and correlated with the end-diastolic area and with changes in cardiac output better than filling pressures. This preliminary study suggests that a standardized ventilatory maneuver may be useful in guiding fluid therapy in ventilated patients.