Low dose spinal with epidural volume extension for renal transplantation in a patient with uremic cardiomyopathy

Abstract

Sir, Patients of renal failure presenting for renal transplant have number of co-morbid conditions namely anaemia, fluid overload, cardiovascular compromise, electrolytes and acid base imbalance, secondary hyperparathyroidism, gastrointestinal and central nervous system symptoms. Prolonged exposure to uremic toxins has been demonstrated to affect myocardial contractility leading to uremic cardiomyopathy.[1] Such changes affect the course of anaesthesia during renal transplantation. The technique of anaesthesia chosen should have minimal cardiovascular effects along with preservation of the function of transplanted organ. We present here a case of uremic cardiomyopathy for renal transplantation managed successfully with low dose spinal with epidural volume extension (EVE). A 22-year-old male patient of renal failure, on maintenance haemodialysis presented for live donor renal transplantation. Patient was found to be controlled hypertensive on medication (tablet nifedipine 20 mg TDS, tablet clonidine 100 μg BD and tablet carvedilol 3.125 mg BD) of a heart rate 52/min, blood pressure 160/100 mm Hg, cardiomegaly in X-ray chest and left ventricular hypertrophy in electrocardiography. Echocardiography revealed global hypokinesia, dilated left ventricle (LV), trivial aortic regurgitation/tricuspid regurgitation and left ventricle ejection fraction 25%. An arteriovenous fistula for haemodialysis was present in left forearm. Pre-operative heparin free haemodialysis was performed on day before surgery. The patient was kept nil per oral for 8 h and received all his antihypertensive drugs as premedication 2 h prior to surgery with a sip of water. In the operating room routine monitoring were attached. Peripheral venous, right radial arterial and right internal jugular vein cannulations were performed under local anaesthesia. The patient was preloaded with normal saline (5 ml/kg body weight [BW]) and combined spinal epidural (CSE) administered in L3-4 interspace in sitting position by midline approach, using 18G CSE set (needle through needle, Portex, Smiths medical ASD Inc., USA). Intrathecal drug administration consisted of 7.5 mg heavy bupivacaine mixed with 25 mcg fentanyl. Epidural catheter was fixed at 7 cm on the skin surface. The patient was turned supine position with slight head down position. After careful aspiration of epidural catheter, 10 ml of 0.9% saline was injected through the catheter over 30 s. A sensory block to pinprick to T6 was achieved within 5 min. Heart rate, arterial blood pressure, SpO2 and temperature were monitored continuously and blood gas samples were obtained every 60 min intra-operatively. Oxygen was given to patient through nasal cannula at the rate of 2 L/min and sedated with injection midazolam 0.04 mg/kg BW. A repeat bolus of 5 ml of 0.5% plain bupivacaine was administered after 90 min through the epidural catheter. Injection methylprednisolone 500 mg and mannitol (20%) 0.5 g/kg BW were administered before the release of vascular clamp. The surgical procedure lasted 3½ h. The patient was haemodynamically stable in the peri-operative period. The patient was shifted to intensive care unit after surgery, where epidural infusion with 0.125% bupivacaine and 2 μg/ml fentanyl at the rate of 5 ml/h was initiated for post-operative analgesia. Patients of poor LV function presenting for renal transplantation are a challenge in peri-operative period. Anaesthetics goals include avoidance of drug induced myocardial depression, maintaining preload and afterload as well as renal perfusion and avoidance of nephrotoxic drugs. General anaesthesia leads to dose related cardiovascular depression, arrhythmia and congestive cardiac failure. Spinal anaesthesia may lead to intense haemodynamic variability secondary to sympathetic blockade as well as limited duration of action. Epidural anaesthesia is an option but may be associated with patchy effect. Recent evidence suggests that CSE anaesthesia (CSEA) is a good alternative for renal transplantation.[2] The technique of CSEA with low dose intrathecal hyperbaric bupivacaine and EVE provided rapid onset with profound surgical anaesthesia due to spinal and ability to prolong the blockade by epidural. Administration of low dose spinal with opioid and EVE not only provided adequate level of block but also provided stable haemodynamics in the peri-operative period. Various authors[3 4] have utilised the technique of EVE to achieve the desired effect, without significant haemodynamic effect and faster recovery of motor function. A study by Blumgart et al.[5] suggested a higher level of analgesia with EVE compared with spinal alone. This is secondary to the volume effect in epidural space which compresses the subarachnoid space and increase the intrathecal spread of the drug. Goy[6] demonstrated that the mean effective dose of intrathecal hyperbaric bupivacaine in CSE was 20% less than that in single shot spinal. Our result was similar to reports of use of the technique in pregnant females with peripartum cardiomyopathy.[7] CSE with EVE technique has been used for gynaecological and orthopaedic surgery, but this is probably the first report of its use in renal transplantation in uremic cardiomyopathy. Patients who have uremic cardiomyopathy and poor LV function are high risk for general anaesthesia, low dose spinal with EVE may be used as an option for providing safe intra-operative anaesthesia and prolong post-operative analgesia.