Anaesthesiological strategies to improve outcome in liver transplantation recipients.

Graft and patients survival are the main goal of anesthesiological management in patients undergoing liver transplantation (LT). Even if anesthesiological practice sustained major developments over time, some evidence-based intraoperative strategies have not yet been widely applied. The aim of this review was to summarize intraoperative anesthesiological strategies which could have the potential to improve LT graft and/or recipient survival. Monitoring must be as accurate as possible in order to manage intraoperative hemodynamic changes. The pulmonary artery catheter still represents the more reliable method to monitor cardiac output by using the intermittent bolus thermodilution technique. Minimally invasive hemodynamic monitoring devices may be considered only in stable cirrhotic patients. Goal-directed fluid-therapy has not yet defined for LT, but it could have a role in optimizing the long-term sequelae associated with volume depletion or overload. The use of vasopressor may affect LT recipient's outcome, by preventing prolonged hypotension, decreasing blood products transfusion and counteracting hepato-renal syndrome. The use of viscoelastic point of care is also warranted in order to reduce blood products requirements. Decreasing mechanical ventilation time, when it is feasible, may considerably improve survival. Finally, monitoring the depth of anesthesia when integrated into an early extubation protocol might have a positive effect on graft function.

Minimum alveolar concentration threshold of sevoflurane for postoperative dream recall.

BACKGROUND: Many factors affect postoperative dream recall, including patient characteristics, type of anesthesia, timing of postoperative interview and stress hormone secretion. Aims of the study were to determine whether Bispectral Index (BIS)-guided anesthesia might decrease sevoflurane minimum alveolar concentration (MAC) when compared with hemodynamically-guided anesthesia, and to search for a MAC threshold useful for preventing arousal, dream recall and implicit memory. METHODS: One hundred thirty patients undergoing elective thyroidectomy were enrolled. Anesthesia was induced with propofol 2 mg kg(-1), fentanyl 3 mcg kg(-1) and cis-atracurium 0.15 mg kg(-1). For anesthesia maintenance, patients were randomly assigned to one of two groups: a BIS-guided group in which sevoflurane MAC was adjusted on the basis of BIS values, and a hemodynamic parameters (HP)-guided group in which MAC was adjusted based on HP. An auditory recording was presented to patients during anesthesia maintenance. Dream recall and explicit/implicit memory were investigated upon awakening and approximately after 24 h. RESULTS: Mean sevoflurane MAC during auditory presentation was similar in the two groups (0.85 ± 0.16 and 0.87 ± 0.17 [P = 0.53] in BIS-guided and HP-guided groups, respectively). Frequency of dream recall was similar in the two groups: 27% (N. = 17) in BIS-guided group, 18% (N. = 12) in HP-guided group, P = 0.37. In both groups, dream recall was less probable in patients anesthetized with MAC values ≥ 0.9 (area under ROC curve = 0.83, sensitivity = 90%, and specificity = 49%). CONCLUSION: BIS-guided anesthesia was not able to generate different MAC values compared to HP-guided anesthesia. Independent of the guide used for anesthesia, a sevoflurane MAC over 0.9 was required to prevent postoperative dream recall.

Low values of left ventricular ejection time in the post-anhepatic phase may be associated with occurrence of primary graft dysfunction after orthotopic liver transplantation: results of a single-centre case-control study.

BACKGROUND: Previous investigations on risk factors for orthotopic liver transplantation (OLT) surgery have not analyzed hemodynamic aberrations in great detail. Moreover, the usefulness of esophageal Doppler monitoring has not been extensively studied in this clinical setting. The aim of this study was to evaluate if the occurrence of primary graft dysfunction (PGD) may be anticipated by hemodynamic indexes measured by esophageal Doppler (ED) monitoring system as well as by pulmonary artery catheter (PAC) in patients undergoing OLT. MATERIALS AND METHODS: 38 OLT recipients were studied. Patients with acute liver failure or having non treated esophageal varices and those transplanted with marginal donors were excluded from the study. The haemodynamic data - measured by ED monitoring system (HemosonicTM 100, Arrow, OK, USA) and PAC - collected at the following 3 time points were considered for statistical analysis: 30 minutes after the induction of anesthesia but before skin incision, T0; 20 minutes after liver dissection, T1; at the beginning of biliary reconstruction, T2. On the basis of early outcome (72 hours after OLT), patients were distinguished into two groups: those with PGD (grade III-IV of Toronto classification) and those without PGD (grade I-II). RESULTS: LVETc (left ventricular ejection time) values, registered at the beginning of biliary reconstruction (T2), were lower in patients with PGD compared to those without PGD (p < 0.000), while there were no differences in hemodynamic parameters derived from PAC between the two groups. CONCLUSIONS: Since LVETc is related to preload, the results of this study would suggest that normovolemia could be the end point of a fluid replacement strategy in OLT setting.

Use of an esophageal echo-Doppler device during liver transplantation: preliminary report.

Determination of cardiac output (CO) is crucial for perioperative monitoring of orthotopic liver transplant (OLT) recipients. A pulmonary artery catheter (PAC) has always been considered the "gold standard" of hemodynamic monitoring. The aim of this study was to evaluate the suitability of a transesophageal echo-Doppler device (ED) as a minimally invasive device to measure CO in OLT. ED was compared with the standard PAC technique taking into account the disease severity of OLT recipients as defined by the model for end-stage liver disease (MELD) score. We enrolled 42 cirrhotic patients scheduled for OLT 3 thermodilution CO measurements were taken by a PAC and the most recent ED measurement (CO(ED)) was also recorded. Paired measurements of CO were performed at standard times, unless there were additional clinical needs. Recipients were stratified into 3 groups according to MELD score: MELD score < or = 15 (14 patients); MELD score between 16 and 28 (17 patients); and MELD score > or = 29 (11 patients). We performed 495 paired measurements of CO. Mean bias was 0.34 +/- 0.9 L/min and limits of agreement were -1.46 and 2.14 L/min. In patients with MELD score <15, the bias was 0.12 +/- 0.55. The ED results were not interchangeable with PAC, because of the large limits of agreement. However, in cirrhotic patients with MELD scores <15, the precision of the new method was similar to that of PAC; therefore, in this subset of patients, it may represent a reliable alternative to PAC.

Balanced anestesia versus total intravenous anestesia for kidney transplantation.

AIM: An ideal anesthetic regimen for kidney transplantation should be able to assure haemodynamic stability to obtain an optimal graft reperfusion. The aim of this study was to compare 2 regimens of anesthesia for patients submitted to kidney transplantation. METHODS: We studied 40 patients: 20 subjects (Group A) received balanced anesthesia with thiopental, fentanyl and isoflurane, to the others 20 (Group B), a total intravenous anesthesia (TIVA) with propofol and remifentanyl was given. In both groups muscle relaxation was obtained with a bolus of cisatracurium followed by a continuous infusion. We performed standard clinical, invasive blood pressure and central venous pressure monitoring. Hemodyna-mic data have been collected at standard times. During the postoperative period we evaluated the recovery (Aldrete Score) in the recovery room and the analgesia (VAS) at 1, 6, 24 h after the end of surgery. RESULTS: The trend of hemodynamic parameters did not show statistically significant differences between the 2 groups. We observed statistically significant differences concerning the quality of the recovery and the postoperative analgesia. The recovery in group B was faster than in group A, but in group A the pain control was better than in group B at least during the first postoperative hour. CONCLUSIONS: For their pharmacokinetic properties, propofol, remifentanyl and cisatracurium allow to obtain a good control of the hemodynamic parameters and a fast and safe recovery of consciousness. Total intravenous anesthesia regimen seems to be an alternative to the balanced anesthesia for patients undergoing kidney transplantation.

Comparison of positive end-expiratory pressure with reverse Trendelenburg position in morbidly obese patients undergoing bariatric surgery: effects on hemodynamics and pulmonary gas exchange.

BACKGROUND: Anesthetized morbidly obese patients often exhibit impaired pulmonary gas exchanges, mostly because of a reduction in functional residual capacity. At present, several approaches are suggested to ventilate these patients. METHODS: The efficiency of positive end-expiratory pressure (PEEP) and reverse Trendelenburg position (RTP) were compared in order to improve oxygenation in 20 morbidly obese patients undergoing bariatric surgery. RESULTS: Both PEEP and RTP determined a significant decrease in alveolar-arterial oxygen difference and an increase in total respiratory compliance (Ctot). RTP resulted in lower airway pressures than PEEP with similar improvements in Ctot and oxygenation. Concerning hemodynamic parameters, cardiac output (CO) significantly decreased with both PEEP and RTP. CONCLUSIONS: RTP and PEEP can be considered adequate ventilatory settings for morbidly obese patients, without any significant difference with regard to gas exchange improvement. However, the decrease in CO may partially counteract the beneficial effects on oxygenation of these ventilatory settings.

Volatile anesthesia in bariatric surgery.

BACKGROUND: Obesity causes anesthesiologists a broad variety of perioperative theoretical and practical problems. The aim of this study was to compare two protocols of anesthesia employing Isoflurane and Sevoflurane and evaluate the cardiorespiratory parameters, postoperative recovery and analgesia. METHODS: 90 patients underwent biliopancreatic diversion. 60 patients (group A) received Isoflurane and 30 patients (group B) were anesthetized with Sevoflurane. Intraoperative monitoring consisted of EKG, invasive arterial pressure, SpO2, EtCO2, Etanest, Spirometry, urinary output and TOF. Cardiorespiratory parameters and end tidal expiratory concentrations of volatile agents were collected during specific phases of surgery: 1) before induction of anesthesia, 2) after intubation, 3) after skin incision, 4) after positioning of costal retractors, 5) in the reverse Trendelenburg position, 6) end of surgery. During the postoperative period the Aldrete test was carried out to evaluate the recovery from anesthesia. VAS was administered for 6 hours after the end of surgery to set the quality of analgesia. RESULTS: No statistically significant differences in cardiorespiratory parameters were found between the two groups. Extubation time was significantly less in the Sevoflurane Group than in the Isoflurane (15 +/- 7 min vs 24 +/- 5 min, p < 0.05). The Sevoflurane Group showed an Aldrete score significantly higher than the Isoflurane (8.8 +/- 0.3 vs 8.1 +/- 0.4, p < 0.05). VAS values did not show statistical differences. CONCLUSION: The introduction of Sevoflurane, a volatile agent with rapid pharmacokinetic properties, seems to offer an interesting application in these patients.

Enteral vs parenteral nutrition after major abdominal surgery: an even match.

HYPOTHESIS: Immediate enteral feeding following major abdominal surgery reduces postoperative complications and mortality when compared with parenteral nutrition. DESIGN: A prospective multicenter randomized trial. SETTING: A university hospital department of digestive surgery. PATIENTS AND INTERVENTIONS: Two hundred forty-one malnourished patients undergoing major elective abdominal surgery were randomly assigned to receive, after surgery, either enteral (enteral nutrition group: 119 patients) or parenteral nutrition (total parenteral nutrition group: 122 patients). The patients were monitored for postoperative complications and mortality. RESULTS: The rate of major postoperative complications was similar in the enteral and parenteral groups (enteral nutrition group: 37.8%; total parenteral nutrition group: 39.3%; P was not significant), as were the overall postoperative mortality rates (5.9% and 2.5%, respectively; P was not significant). CONCLUSION: The present study failed to demonstrate that enteral feeding following major abdominal surgery reduces postoperative complications and mortality when compared with parenteral nutrition.

The effects of the reverse trendelenburg position on respiratory mechanics and blood gases in morbidly obese patients during bariatric surgery.

Anesthesia adversely affects respiratory function, particularly in morbidly obese patients. Although many studies have been performed to determine the optimal ventilatory settings in these patients, this question has not been answered. The aim of this study was to evaluate the effect of reverse Trendelenburg position (RTP) on gas exchange and respiratory mechanics in 15 obese patients undergoing biliopancreatic diversion. A standardized anesthetic regimen was used and patients were examined at standard times: 1) after tracheal intubation, 2) after laparotomy, 3) after positioning of subcostal retractors, 4) with retractors in RTP. The measurements of respiratory mechanics were repeated for a wide range of tidal volumes by using the technique of rapid occlusion during constant flow inflation. We noted a wide alveolar-arterial oxygen difference [P(A-a)O(2)] in all patients, particularly during Phase 3. When the patients were placed in RTP, P(A-a)O(2) showed a significant improvement and a return toward baseline values. As for mechanics, total respiratory system compliance was significantly higher in RTP than in the other phases. In conclusion, our data suggest that RTP is an appropriate intraoperative posture for obese subjects because it causes minimal arterial blood pressure changes and improves oxygenation.