Interchangeability of transthoracic and transesophageal echocardiographic right heart measurements in the perioperative setting and correlation with hemodynamic parameters.

Reduction of right ventricular (RV) function after cardiac surgery has been shown to impact outcomes. Conventional indices for right ventricular dysfunction are validated using transthoracic echocardiogram (TTE) which has limited use compared to transesophageal echocardiogram (TEE) in the perioperative settings. The aim of this study was to assess the agreement of RV systolic function assessment with TEE compared to TTE and assess the association of echocardiographic parameter with hemodynamic indices of RV dysfunction. This was a single center prospective observational study in an academic institution. Fifty adult patients undergoing elective cardiac surgery were included. TTE, TEE and stroke volume measurements pre-cardiopulmonary bypass (CPB) and post-CPB were performed. The variables of interest were anatomical M-mode tricuspid annular plane systolic excursion (AMM-TAPSE), fractional area change (FAC), tricuspid annular velocity (S') and myocardial performance index (MPI). FAC and AMM-TAPSE measured at the mid-esophageal 4 chamber view had substantial agreement with the TTE acquired parameters (Lin's concordance correlation coefficient (CCC) = 0.76, 95%CI 0.59-0.86 and CCC = 0.85, 95%CI 0.76-0.91). S' was significantly underestimated by TEE (CCC = 0.07, 95%CI 0.04-0.19) and MPI showed moderate agreement (CCC = 0.45 95%CI 0.19-0.65). Despite the significant changes in echocardiographic parameters, there were no corresponding changes in stroke volume (SV) or pulmonary artery pulsatility index at the post-CPB period. TEE acquired FAC and AMM-TAPSE had substantial agreement with pre-operative TTE values and no significant differences between the pre-CPB and post-CPB period. Systolic RV echocardiographic parameters decreased post-CPB but this was not accompanied by significant hemodynamic changes.

Migration of an Inferior Vena Cava Tumor Thrombus during Renal Cell Carcinoma Resection.

Approximately 4%-10% of patients with renal cell carcinoma (RCC) have tumoral vascular invasion with resultant thrombi in the renal vein and in the inferior vena cava (IVC). The authors describe an interesting case of IVC tumor thrombus that migrated to the right cardiac chambers during RCC resection. The diagnosis was made by intraoperative transesophageal echocardiography (TEE), which revealed the presence of a free-floating thrombus between the right atrium (RA) and right ventricle (RV). The patient required an urgent sternotomy with cardiopulmonary bypass (CPB) for atrial thrombus removal prior to the completion of the nephrectomy. The patient made a full recovery and was discharged to a rehabilitation facility. These findings illustrate the importance of intraoperative TEE monitoring during nephrectomy and IVC thrombectomy. In this case, TEE allowed for the diagnosis of an unexpected complication necessitating prompt cardiac surgical management.

The multidisciplinary management of a mechanical mitral valve thrombosis in pregnancy: a case report and review of the literature.

Background: The management of anticoagulation for mechanical heart valves during pregnancy poses a unique challenge. Mechanical valve thrombosis is a devastating complication for which surgery is often the treatment of choice. However, cardiac surgery for prosthetic valve dysfunction in pregnant patients confers a high risk of maternofetal morbidity and mortality. Case summary: A 39-year-old woman in her first pregnancy at 30 weeks gestation presented to hospital with a mechanical mitral valve thrombosis despite therapeutic anticoagulation with low-molecular-weight heparin. She underwent an emergent caesarean section followed immediately by a bioprosthetic mitral valve replacement. This occurred after careful planning and organization on the part of a large multidisciplinary team. Discussion: A proactive, rather than reactive, approach to the surgical management of a mechanical valve thrombosis in pregnancy will maximize the chances of successful maternal and fetal outcomes.

Albumin and fibrinogen kinetics in sepsis: a prospective observational study.

BACKGROUND: The measurement of circulating substrate concentrations does not provide information about substrate kinetics. It, therefore, remains unclear if a decrease in plasma concentration of albumin, as seen during critical illness, is a consequence of suppressed production in the liver or increased peripheral clearance. In this study, using stable isotope tracer infusions, we measured albumin and fibrinogen kinetics in septic patients and in a control group of non-septic subjects. METHODS: With the approval from the institutional Research Ethics Board and after obtaining written informed consent from patients or their substitute decision maker, mechanically ventilated patients with sepsis and patients scheduled for elective coronary artery bypass grafting were enrolled. Patients in the non-sepsis group were studied on the day before surgery. The stable isotope L-[ring-2H5]phenylalanine was used to measure absolute synthesis rates (ASR) of albumin and fibrinogen. A priming dose of L-[ring-2H5]phenylalanine (4 µmol/kg) was given followed by a six-hour infusion at a rate of 0.15 µmol/kg/min. At baseline and hourly thereafter, blood was drawn to measure isotope enrichments by gas chromatography/mass spectrometry. Very low density lipoprotein apolipoprotein-B 100 isotopic enrichment was used to represent the isotopic enrichment of the phenylalanine precursor pool from which the liver synthesizes proteins. Plasma albumin and fibrinogen concentrations were also measured. RESULTS: Mean plasma albumin in septic patients was decreased when compared to non-septic patients, while synthesis rates were comparable. Mean plasma fibrinogen and ASR in septic patients was increased when compared to non-septic patients. In non-septic patients, no statistically significant correlation between plasma albumin and ASR was observed but plasma fibrinogen significantly correlated with ASR. In septic patients, plasma albumin and fibrinogen significantly correlated with ASR. CONCLUSIONS: While septic patients showed lower plasma albumin levels than non-septic patients, albumin synthesis was similar in the two groups suggesting that hypoalbuminemia during sepsis was not caused by suppressed hepatic production but a result of enhanced clearance from the circulation. Hyperfibrinogenemia in septic patients was a consequence of increased fibrinogen production. TRIAL REGISTRATION: ClinicalTrials.gov: NCT02865408 (registered on August 12, 2016) and ClinicalTrials.gov: NCT02549443 (registered on September 15, 2015).

Irreversible Acquired Noncompaction Cardiomyopathy in a Parturient with Corrected Atrial Septal Defect: A Case Report and Clinical Implications.

Left ventricular noncompaction (LVNC) is described as a cardiomyopathy with an increase in left ventricle trabeculations and recesses. We report a rare case of persistent pregnancy-acquired LVNC cardiomyopathy and review the anesthetic peripartum management strategies. A 33-year-old parturient was followed closely by the high-risk obstetric service for her second pregnancy. She had an unresolved LVNC cardiomyopathy that was diagnosed during her first pregnancy for which she had a caesarean section. Her symptoms included occasional palpitations and dyspnea. She was started on metoprolol and enoxaparin. A successful caesarean section was performed at 37 weeks gestation under regional anesthesia. Echocardiograms prior to and during the second pregnancy demonstrated persistence of the LV hypertrabeculations, LV systolic dysfunction, and a left ventricular ejection fraction (LVEF) of 35%. Pregnancy-induced LV hypertrabeculations occur in a significant proportion of women, but most cases spontaneously resolve completely. Favorable maternal and fetal outcomes require multidisciplinary care and careful selection of the anesthetic technique and drugs that maintain stable hemodynamics.

Parenteral amino acid supplementation with high-dose insulin prevents hypoaminoacidemia during cardiac surgery.

OBJECTIVES: Surgery triggers a stress response that produces insulin resistance and hyperglycemia. During cardiac surgery, the administration of high-dose insulin along with dextrose titration maintains normoglycemia, but dramatically decreases plasma amino acids (AAs) compared with preoperative fasting levels. Hypoaminoacidemia limits protein synthesis and prevents anabolic responses after surgery. We investigated whether parenteral infusion of AAs during and immediately after cardiac surgery would prevent hypoaminoacidemia in patients who receive high-dose insulin therapy. METHODS: Sixteen patients undergoing coronary artery bypass grafting surgery were randomly allocated to receive AAs with % kcal equivalent to either 20% (n = 8) or 35% (n = 8) of their measured resting energy expenditure (REE). Insulin was infused at a constant rate of 5 mU/(kg × min), whereas dextrose was titrated to maintain normoglycemia during and until 5 h after surgery. Plasma AA concentrations were measured at baseline before and after surgery. RESULTS: Compared with the 20% AA group after surgery, AA concentrations were significantly higher in the 35% AA group for 12 of 20 AAs (P < 0.032), including all branched-chain AAs. In the 20% AA group, total essential AAs decreased by 21% and nonessential AAs decreased by 14% after surgery compared with preoperative fasting levels. In contrast, giving 35% AAs prevented this unfavorable decrease in AAs, and in fact allowed for a 23% and 12% increase in essential and nonessential AAs, respectively. CONCLUSIONS: AA supplementation at 35% REE, but not 20% REE, can effectively prevent hypoaminoacidemia caused by high-dose insulin therapy during cardiac surgery.

Early results of a modified biological valved conduit for the Bentall procedure.

INTRODUCTION: Few bioprosthetic valved conduits for aortic root surgery are commercially available. Long-term Warfarin therapy (mechanical), potential root calcification (xeno- or homograft valves), and the need for additional ascending aorta grafts are concerns associated with currently used valved conduits. A simplified, self-assembled bioroot conduit comprising currently available materials that facilitates future intervention and exhibits advantages of a bioprosthesis was used. METHODS: From November 2015 to January 2017, 17 consecutive patients underwent urgent or elective aortic root surgery. A bioroot conduit, constructed using 28 or 30 mm of sinus of Valsalva Gelweave tube graft and a 3 to 5 mm smaller bioprosthetic Trifecta valve sewn into the sinus of Valsalva base, was preconstructed in the operating room before sternotomy. The size of the valved conduit was based on the distal ascending aorta or proximal arch and not aortic annular dimension. The bioroot was sutured to the native aortic annulus at the level of the bottom skirt of the Valsalva graft without contacting the sewing cuff of the bioprosthetic valve. RESULTS: All patients survived the operation and were discharged home without long-term anticoagulation therapy. The mean age was 65 ± 12 years, and 13 patients were male. The cardiopulmonary bypass duration was 169 ± 84 minutes, and the cross-clamp (XC) duration was 110 ± 32 minutes. The operation was elective in 12 patients, urgent/emergent in five, and redo in three. CONCLUSION: A simplified self-assembled bioroot Bentall conduit is appropriate for aortic root reconstruction. Use of a patient-tailored valved conduit will not prolong the cardiac ischemic time and will facilitate future valve replacement.

Hyperinsulinemic Normoglycemia during Cardiac Surgery Reduces a Composite of 30-day Mortality and Serious In-hospital Complications: A Randomized Clinical Trial.

BACKGROUND: Hyperinsulinemic normoglycemia augments myocardial glucose uptake and utilization. We tested the hypothesis that hyperinsulinemic normoglycemia reduces 30-day mortality and morbidity after cardiac surgery. METHODS: This dual-center, parallel-group, superiority trial randomized cardiac surgical patients between August 2007 and March 2015 at the Cleveland Clinic, Cleveland, Ohio, and Royal Victoria Hospital, Montreal, Canada, to intraoperative glycemic management with (1) hyperinsulinemic normoglycemia, a fixed high-dose insulin and concomitant variable glucose infusion titrated to glucose concentrations of 80 to 110 mg · dl; or (2) standard glycemic management, low-dose insulin infusion targeting glucose greater than 150 mg · dl. The primary outcome was a composite of 30-day mortality, mechanical circulatory support, infection, renal or neurologic morbidity. Interim analyses were planned at each 12.5% enrollment of a maximum 2,790 patients. RESULTS: At the third interim analysis (n = 1,439; hyperinsulinemic normoglycemia, 709, standard glycemic management, 730; 52% of planned maximum), the efficacy boundary was crossed and study stopped per protocol. Time-weighted average glucose concentration (means ± SDs) with hyperinsulinemic normoglycemia was 108 ± 20 versus 150 ± 33 mg · dl with standard glycemic management, P < 0.001. At least one component of the composite outcome occurred in 49 (6.9%) patients receiving hyperinsulinemic normoglycemia versus 82 (11.2%) receiving standard glucose management (P < efficacy boundary 0.0085); estimated relative risk (95% interim-adjusted CI) 0.62 (0.39 to 0.97), P = 0.0043. There was a treatment-by-site interaction (P = 0.063); relative risk for the composite outcome was 0.49 (0.26 to 0.91, P = 0.0007, n = 921) at Royal Victoria Hospital, but 0.96 (0.41 to 2.24, P = 0.89, n = 518) at the Cleveland Clinic. Severe hypoglycemia (less than 40 mg · dl) occurred in 6 (0.9%) patients. CONCLUSIONS: Intraoperative hyperinsulinemic normoglycemia reduced mortality and morbidity after cardiac surgery. Providing exogenous glucose while targeting normoglycemia may be preferable to simply normalizing glucose concentrations.

Perioperative fluid management in kidney transplantation: a black box.

The incidence of delayed graft function in patients undergoing kidney transplantation remains significant. Optimal fluid therapy has been shown to decrease delayed graft function after renal transplantation. Traditionally, the perioperative volume infusion regimen in this patient population has been guided by central venous pressure as an estimation of the patient's volume status and mean arterial pressure, but this is based on sparse evidence from mostly retrospective observational studies. Excessive volume infusion to the point of no further fluid responsiveness can damage the endothelial glycocalyx and is no longer considered to be the best approach. However, achievement of adequate flow to maintain sufficient tissue perfusion without maximization of cardiac filling remains a challenge. Novel minimally invasive technologies seem to reliably assess volume responsiveness, heart function and perfusion adequacy. Prospective comparative clinical studies are required to better understand the use of dynamic analyses of flow parameters for adequate fluid management in kidney transplant recipients. We review perioperative fluid assessment techniques and discuss conventional and novel monitoring strategies in the kidney transplant recipient.

An up-down determination of the required seated duration after intrathecal injection of bupivacaine and fentanyl for the prevention of hypotension during Cesarean delivery.

PURPOSE: A prolonged seated time after intrathecal injection of hyperbaric bupivacaine and morphine is related to the incidence of hypotension during Cesarean delivery, but results in a high incidence of pain during peritoneal closure. We conducted this study to determine the effect of the addition of intrathecal fentanyl on the relationship between seated time and hypotension and intraoperative analgesia requirements. METHODS: Women undergoing Cesarean delivery were randomized to receive an intrathecal injection of either 11.25 or 15 mg of hyperbaric bupivacaine with morphine 150 µg and fentanyl 15 µg using a combined spinal-epidural technique. The seated duration following intrathecal injection was assigned using up-down methodology. If the preceding patient was hypo- or normotensive, the next patient sat for 15 sec more or less, respectively. A systolic blood pressure < 80% of the preoperative value was defined as hypotension; a standardized anesthetic was administered, and the presence of pain during the procedure was recorded. Isotonic regression of pooled adjacent violators was used to determine the time at which 50% of each group would avoid hypotension (i.e., the median effective seated time). RESULTS: There were 15 patients in each group. The median seated time was 129 sec (95% confidence interval [CI], 116 to 150) for the 11.25-mg group and 459 sec (95% CI, 444 to 471) for the 15-mg group. Only one (3%) of the 30 patients in the study had pain on peritoneal closure, and this was successfully treated with intravenous fentanyl. CONCLUSION: We have determined the seated time required following intrathecal injection of hyperbaric bupivacaine, morphine, and fentanyl to prevent hypotension in 50% of patients undergoing Cesarean delivery. TRIAL REGISTRATION: www.clinicaltrials.gov , NCT01896960. Registered 2 July 2013.

Role of nutrition support in adult cardiac surgery: a consensus statement from an International Multidisciplinary Expert Group on Nutrition in Cardiac Surgery.

Nutrition support is a necessary therapy for critically ill cardiac surgery patients. However, conclusive evidence for this population, consisting of well-conducted clinical trials is lacking. To clarify optimal strategies to improve outcomes, an international multidisciplinary group of 25 experts from different clinical specialties from Germany, Canada, Greece, USA and Russia discussed potential approaches to identify patients who may benefit from nutrition support, when best to initiate nutrition support, and the potential use of pharmaco-nutrition to modulate the inflammatory response to cardiopulmonary bypass. Despite conspicuous knowledge and evidence gaps, a rational nutritional support therapy is presented to benefit patients undergoing cardiac surgery.

The Labor Analgesia Requirements in Nulliparous Women Randomized to Epidural Catheter Placement in a High or Low Intervertebral Space.

BACKGROUND: We hypothesized that an epidural catheter placed in a lower vertebral interspace will require less medication for labor analgesia. METHODS: Nulliparous women requesting neuraxial labor analgesia were randomized to epidural catheter placement at the ultrasound-confirmed L1-2 or L4-5 interspace. Patient-controlled epidural analgesia and breakthrough manual epidural boluses of 10 mL of 0.125% bupivacaine with 50 µg of fentanyl or 8 mL of 2% lidocaine were utilized. Abdominal and perineal pain scores were assessed at 30 and 60 minutes after standardized initiation of epidural analgesia. Pain scores during pushing were assessed after delivery. The primary outcome was the proportion of patients requiring manual boluses and was compared using a χ test. Secondarily, we analyzed the number of boluses given in early (up to 4 hours before delivery) versus late labor using χ tests and the pain scores using Mann-Whitney U tests, with adjustment of P values for multiple testing. RESULTS: We analyzed 148 patients. Overall, the percentage of patients in the low versus high groups who required manual boluses was 46% vs 51% (P = 1.0). For the 56 patients in each group who delivered vaginally, 22 (52%) vs 20 (48%) manual boluses were given to the low epidural group in early versus late labor, compared to 9 (20%) vs 36 (80%) in the high epidural group (P = .014). There was no statistical difference in patient-controlled epidural analgesia requirements or patient satisfaction. Comparing the low versus high groups, the median (interquartile range) pain scores were: 3 (1, 6) vs 0 (0, 2) (P = .013) at 30 minutes and 1 (1, 3) vs 0 (0, 1) (P = .013) at 60 minutes for abdominal pain; 0 (0, 2) vs 1 (1, 3) (P = .36) and 0 (0, 1) vs 1 (1, 3) (P = .014) at these same time points for perineal pain; and 1 (0, 5) vs 0 (0, 3) (P = .9) for abdominal and 2 (0, 5) vs 4 (1, 8) (P = .025) for perineal pain during pushing. The percentage of patients who underwent instrumental delivery was 15% vs 5% (P = .06) for the low versus high group. CONCLUSIONS: An L4-5 epidural catheter initially provides less relief of abdominal pain but more relief of perineal labor pain. Patients with an L4-5 catheter require more manual boluses during early labor but less during late labor. The possible association of low epidural catheters with instrumental delivery merits further investigation.

Hyperinsulinemic-normoglycemic clamp administered together with amino acids induces anabolism after cardiac surgery.

Cardiac surgery triggers an inflammatory stress response, leading to protein catabolism, a process that even high-dose insulin therapy alone cannot reverse. To determine whether hyperinsulinemic-normoglycemic clamp and perioperative amino acid (AA) supplementation improves whole body protein balance, 20 patients scheduled for elective coronary artery bypass grafting surgery were randomly assigned to have intra- and postoperative hyperinsulinemic-normoglycemic clamp, with or without intravenous AA supplementation. Primed continuous infusions of [6,6-2H2]glucose and l-[1-13C]leucine were used to quantify whole body protein and glucose metabolism before and after surgery. Adipose tissue and serum cytokines were also analyzed to measure their responsiveness to the anabolic effect of AA administration. During hyperinsulinemic-normoglycemic clamp, AA supplementation successfully stimulated whole body protein synthesis, resulting in a positive whole body protein balance after surgery (insulin: -13.6 ± 4.5 vs. insulin + AA: 2.1 ± 5.4 µmol·kg-1·h-1, P < 0.001). Endogenous glucose production was equally suppressed in both groups (insulin: 0.0 ± 3.8 vs. insulin + AA 1.6 ± 1.6 µmol·kg-1·min-1, P = 0.230). AA supplementation led to significant changes in serum and tissue IL-6 (insulin: 246.6 ± 111.2 vs. insulin + AA: 124.5 ± 79.3 pg/ml, P = 0.011). In conclusion, hyperinsulinemic-normoglycemic clamp technique, together with AA supplementation, can induce an anabolic state after open-heart surgery, as quantified by a positive whole body protein balance.

Glucose and insulin administration while maintaining normoglycemia inhibits whole body protein breakdown and synthesis after cardiac surgery.

We investigated the effect of insulin administered as part of a hyperinsulinemic-normoglycemic clamp on protein metabolism after coronary artery bypass grafting (CABG) surgery. Eighteen patients were studied, with nine patients in the control group receiving standard metabolic care and nine patients receiving insulin (5 mU·kg(-1)·min(-1)). Whole body glucose production, protein breakdown, synthesis, and oxidation were determined using stable isotope tracer kinetics (l-[1-(13)C]leucine, [6,6-(2)H2]glucose) before and 6 h after the procedure. Plasma amino acids, cortisol, and lactate were also measured. Endogenous glucose production (preoperatively 10.0 ± 1.6, postoperatively 3.7 ± 2.5 µmol·kg(-1)·min(-1); P = 0.0001), protein breakdown (preoperatively 105.3 ± 9.8, postoperatively 85.2 ± 9.2 mmol·kg(-1)·h(-1); P = 0.0005) and synthesis (preoperatively 88.7 ± 8.7, postoperatively 72.4 ± 8.4 mmol·kg(-1)·h(-1); P = 0.0005) decreased in the presence of hyperinsulinemia, whereas both parameters remained unchanged in the control group. A positive correlation between endogenous glucose production and protein breakdown was observed in the insulin group (r(2) = 0.385). Whole body protein oxidation and balance decreased after surgery in patients receiving insulin without reaching statistical significance. In the insulin group the plasma concentrations of 13 of 20 essential and nonessential amino acids decreased to a significantly greater extent than in the control group. In summary, supraphysiological hyperinsulinemia, while maintaining normoglycemia, decreased whole body protein breakdown and synthesis in patients undergoing CABG surgery. However, net protein balance remained negative.