Epidurals for liver transplantation – Where are we?

Thoracic epidural analgesia (TEA) has been used as a mode of postoperative pain relief for orthotopic liver transplants (OLT) in a selected group of patients. It is not widely practiced in view of the impaired haemostasis associated with end-stage liver disease and severe unpredictable intraoperative coagulopathy. TEA in OLT may not be the technique of choice for routine administration of postoperative analgesia, but can be considered in patients who have a normal coagulation profile preoperatively. Safe conduct of TEA in OLT involves anaesthetic expertise and stringent monitoring in the postoperative period. This review discusses the status of thoracic epidural analgesia in patients undergoing an orthotopic liver transplant

Intraoperative cardiovascular monitoring in hypertensive patients

Bacground and Purpose: Hypertensive patients are more prone to perioperative ischaemia, arrythmias and cardiovascular instability. Attention should be paid to the presence of target organ damage, such as coronary artery disease. Material and Method: Haemodynamically unstable patients undergoing major surgery require more complex haemodynamic monitoring. Multiple studies have demonstrated the favourable outcome achieved by goal-directed fluid management during the intraoperative period. Conclusion: The trend in intraoperative haemodynamic monitoring, a key feature of anaesthetic practice is towards less invasive systems that provide continuous information. A balance is needed between the hazards of an invasive approach and the desire for a continuous stream of accurate information that is robust enough to withstand the surgical and physiological challenges in hypertensive patients. In spite of its importance for anaesthetists, there is no consensus as to which system is best. This review examines the recent developments in haemodynamic monitoring

Intraoperative cardiovascular monitoring in hypertensive patients

Bacground and Purpose: Hypertensive patients are more prone to perioperative ischaemia, arrythmias and cardiovascular instability. Attention should be paid to the presence of target organ damage, such as coronary artery disease. Material and Method: Haemodynamically unstable patients undergoing major surgery require more complex haemodynamic monitoring. Multiple studies have demonstrated the favourable outcome achieved by goal-directed fluid management during the intraoperative period. Conclusion: The trend in intraoperative haemodynamic monitoring, a key feature of anaesthetic practice is towards less invasive systems that provide continuous information. A balance is needed between the hazards of an invasive approach and the desire for a continuous stream of accurate information that is robust enough to withstand the surgical and physiological challenges in hypertensive patients. In spite of its importance for anaesthetists, there is no consensus as to which system is best. This review examines the recent developments in haemodynamic monitoring

Large volume dye spread in transversus abdominis plane block via three injection sites: a cadaveric study

Background: Transversus abdominis plane (TAP) block is a recently described regional anaesthesia technique that provides analgesia for the abdominal wall. Three access points for injection have been described: via the lumbar triangle of Petit (LTOP), via the midaxillary line and via the subcostal region (SC). This study aimed to investigate the spread of dye following injection via all 3 sites with a large volume injectate. Materials and Methods: 24 hemiabdomens were injected with 40 mL 25% black food dye: 8 via the LTOP) 4 via the MAL, 4 via the SC. Dissection was performed to reveal the extent of nerve involvement and dye spread. Results: Variation in the size and shape of the LTOP was found between cadavers. Mean areas of dye spread (range of nerve involvement) in the remaining 16 hemiabdomens for LTOP, MAL and SC were 77.9 cm2 (T10-ilioinguinal), 50.3 cm2 (T10-ilioinguinal) and 91.3 cm2 (T7-ilioinguinal) respectively. Communications were seen between nerves within the TAP in one dissection. Dye staining was seen to involve nerves outside the TAP. Conclusion: Subcostal injection gives more superior dye spread, with a greater area and awider range of nerve involvement. This should perhaps be the preferred injection site, and could have broader indications

Efficacy of pro- and anticoagulant strategies in plasma of patients undergoing hepatobiliary surgery

BACKGROUND: In vitro efficacy of pro- and antihemostatic drugs is profoundly different in patients with compensated cirrhosis and in those who have cirrhosis and are critically ill. OBJECTIVES: Here we assessed the efficacy of pro- and anticoagulant drugs in plasma of patients undergoing hepato-pancreato-biliary (HPB) surgery, which is associated with unique hemostatic changes. METHODS: We performed in vitro analyses on blood samples of 60 patients undergoing HPB surgery and liver transplantation: 20 orthotopic liver transplantations, 20 partial hepatectomies, and 20 pylorus-preserving pancreaticoduodenectomies. We performed thrombin generation experiments before and after in vitro addition of fresh frozen plasma (FFP), prothrombin complex concentrate (PCC), recombinant factor VIIa (rFVIIa), low molecular weight heparin (LMWH), unfractionated heparin, dabigatran, and rivaroxaban. RESULTS: We showed that patients undergoing HPB surgery are in a hypercoagulable state by thrombin generation testing. FFP and rFVIIa had minimal effects on thrombin generation, whereas PCC had a more pronounced procoagulant effect in patients compared with controls. Dabigatran showed a more pronounced anticoagulant effect in patients compared with controls, whereas rivaroxaban and LMWH had a decreased anticoagulant effect in patients. CONCLUSION: We demonstrate profoundly altered in vitro efficacy of commonly used anticoagulants, in patients undergoing HPB surgery compared with healthy controls, which may have implications for anticoagulant dosing in the early postoperative period. In the correction of perioperative bleeding complications, PCCs appear much more potent than FFP or rFVIIa, and PCCs may require conservative dosing and caution in use in patients undergoing HPB surgery

Interval forecasts based on regression trees for streaming data

In forecasting, we often require interval forecasts instead of just a specific point forecast. To track streaming data effectively, this interval forecast should reliably cover the observed data and yet be as narrow as possible. To achieve this, we propose two methods based on regression trees: one ensemble method and one method based on a single tree. For the ensemble method, we use weighted results from the most recent models, and for the single-tree method, we retain one model until it becomes necessary to train a new model. We propose a novel method to update the interval forecast adaptively using root mean square prediction errors calculated from the latest data batch. We use wavelet-transformed data to capture long time variable information and conditional inference trees for the underlying regression tree model. Results show that both methods perform well, having good coverage without the intervals being excessively wide. When the underlying data generation mechanism changes, their performance is initially affected but can recover relatively quickly as time proceeds. The method based on a single tree performs the best in computational (CPU) time compared to the ensemble method. When compared to ARIMA and GARCH modelling, our methods achieve better or similar coverage and width but require considerably less CPU time

Does epidural clonidine improve postoperative analgesia in major vascular surgery?

Aim To determine the quality and duration of the analgesic and haemodynamic effects of clonidine when used as an additional analgesic for postoperative epidural analgesia in major vascularsurgery. Methods The prospective, single-blinded study involved 60 patients randomised into three groups (20 patients each): Group BM—bupivacaine 0.125% and morphine 0.1 mg/ml; Group BC—bupivacaine 0.125% and clonidine 5 μg/ml; Group MC—morphine 0.1 mg/ml and clonidine 5 μg/ml continuously infused at 5 ml/h. The quality and duration of the analgesia measured by the Visual Analogue Scale (VAS) at rest and on movement, additional analgesia requirements, sedation scores, haemodynamic parameters and side effects(respiratory depression, motor block, toxic effects, nausea and pruritus) were recorded. Results The average VAS scores at rest and on movement were significantly lower in Group MC at two, six and 24 hours following the start of epidural infusion (P<0.05). The duration of the analgesic effect after finishing the epidural infusion was significantly longer in Group MC (P<0.05). Patients from Group MC were intubated longer. Additional analgesia consumption, sedation scoresand haemodynamic profiles were similar in all three groups. Prurituswas more frequent in morphine groups (P<0.05), but other sideeffects were similar in all three groups.Conclusion Under study conditions, clonidine added to morphine,not 0.125% bupivacaine, provided significantly better pain scoresat two, six and 24 hours following the start of epidural infusionand the longest-lasting analgesia following the discontinuationof epidural infusion. However, patients from the Group MC weremechanically ventilated longer than patients from other two groups.Continuous monitoring of the patient is necessary after theadministration of clonidine for epidural analgesia

Three different approaches to Transversus abdominis plane

Aim The transversus abdominis plane (TAP) block is a new techniquefor providing analgesia to the anterior abdominal wall. There is ongoing debate regarding access point for TAP block. The aim of this cadaveric study was to compare the spread of 40 mL of dye using three different approaches to TAP: subcostal , via the mid-axillary and via the lumbar triangle of Petit (LTOP). Methods Injection of black dye into the TAP was performed for each hemi-abdominal wall of 13 embalmed human cadavers by using 3 different access points: subcostal (9 hemi-abdomens), mid-axillary (9) and LTOP (8). This was followed by dissection to determine the extent of dye spread and nerve involvement in the dye injection. The shapes of the dye were traced onto clear plastic, which was then photographed. These digital photographs were loaded into the mathematical software programme Matlab, and the outline of the dye spread was digitised using a piecewise cubic spline, enabling the shapes to be plotted on a graph and the areas to be calculated. Results The area of the dye spread for subcostal, mid-axillary and LTOP was 85.1 (T7-L1), 58.9 (T10-L1) and 77.9cm2 (T10-L1), respectively. There was statistically significant difference between area of dye spread between subcostal and mid-axillary approach (p<0.01). Conclusion This dye injection study in a cadaver model indicates that subcostal approach is associated with a larger area of spread of dye than the mid-axillary approach. Dye injected through subcostal, mid-axillary and LTOP approaches demonstrated different nerve involvement