Anesthesia for bench surgery

Abstract

Surgical removal of the kidney tumor outside the body, (ex vivo renal bench surgery) followed by auto transplantation is an emerging and often done procedure to reconstruct the urinary tract. It possesses immense challenges to both the anesthesiologists and the surgeons. The risks are multiplied if you are performing the surgery on a solitary functioning kidney. Here, we are describing the anesthetic management of 70-year-old male post nephrectomy patient undergoing renal auto transplantation by bench surgery. Our primary goals for perioperative management were to maintain a stable hemodynamics throughout the procedure, to reduce fluid overload during the period of extracorporeal surgery, to maintain perfusion for the transplanted solitary kidney, to control bleeding to a minimum, and to provide adequate analgesia for the patient. We made use of a balanced anesthetic technique and stringent monitoring standards to bring forth a successful outcome for the patient. At the end of his hospital stay, patient went home with a healthy, normally functioning kidney.

INTRODUCTION

Extracorporeal bench surgery and autotransplantation of kidney essentially means to remove the diseased kidney from the patient's body, conduct an ex vivo dissection or repair on the kidney, and finally to transplant it to the same patient onto a different location of his body. Most commonly, the selected site is the ipsilateral iliac fossa. This procedure was first successfully conducted by Hardy in 1963 in a patient with severe ureteral injury following aortic surgery.[1] With the advent of microvascular techniques and renal preservation, this procedure is now performed in many centers. Now that there is a critical shortage of kidney donations, and since patients with tumors are not a priority for transplant centers; autotransplantation is popularly suggested in such patients. Apart from this, autotransplantation is indicated in a wide variety of conditions such as renal artery stenosis, severe ureteral damage, complex nephrolithiasis, and retroperitoneal fibrosis.[2] Other than renal indications, this technique has been tried to treat hepatic tumors with promising results.[3]

Renal transitional cell carcinoma (TCC), or renal urothelial carcinoma, is the most common malignant tumor of the renal pelvis.[4] It arises from the transitional (urothelial) epithelial cells lining the urinary tract. Surgical intervention is the main form of radical treatment for localized disease. There is a considerably high chance in recurrence of the tumor in the contralateral kidney even after radical nephroureterectomy owing to its multifocal nature.[5] In such cases, where a solitary functioning kidney gets affected, conservative procedures are preferred. Our patient had a similar history. He had recurrence in his solitary functioning kidney, following a radical procedure on the contralateral organ. Hence, the surgical team decided to go for autotransplantation following an extracorporeal surgical resection.

CASE REPORT

The patient was a 70-year-old male who was a known hypertensive and type 2 diabetic. He had already undergone right nephroureterectomy for the right renal pelvis TCC under general anesthesia 5 years back from another hospital. He was on regular follow-up since then. During one such follow-up, his computed tomography scan showed an incidental finding of features suggestive of neoplasm in the opposite kidney. Then, he got admitted to our hospital for further definitive procedure. After further evaluation, he was posted for laparoscopic assisted left radical nephroureterectomy, bench surgery, and auto transplantation under general anesthesia.

Apart from being hypertensive and diabetic, he had no other comorbidities. He was taking oral losartan and hydrochlorothiazide for hypertension, which was well under control. He was on oral hypoglycemic agents (metformin and sitagliptin) which was switched over to insulin since he got admitted. He had undergone an open reduction and internal fixation of fractured tibia under spinal anesthesia 37 years back. He did not give any history of adverse anesthetic events occurring during any of those procedures. He was a nonsmoker, with moderate effort tolerance. His routine blood reports were normal except for dyslipidemia. He was then started on rosuvastatin. His fasting blood sugar (FBS) was 108 g%. Serum creatinine was 1.2 mg%. His electrocardiogram showed a solitary T wave inversion in aVL. Chest X-ray was normal. His echocardiography report showed that he had good left ventricular (LV) function with an ejection fraction of 71%, mild LV hypertrophy, and LV diastolic dysfunction.

On the previous night of surgery, we had given him oral nitrazepam 5 mg and oral pantoprazole 40 mg. His hemoglobin and serum electrolyte reports on the day of surgery were found to be normal. The morning dose of insulin was skipped and his FBS was 116 mg%. Informed consent was obtained from the patient and his relatives. He was then premedicated with injection midazolam 1 mg intravenous (IV), injection glycopyrrolate 0.2 mg IV, and injection ondansetron 4 mg IV. Inside the theater, his right radial artery was cannulated. Before induction, we passed a 20-gauge epidural catheter through the T11–T12 interspace using an 18-gauge Tuohy needle and kept 5 cm of the catheter in situ for continuous infusion during the perioperative period. We induced the patient with IV fentanyl 100 µg and IV propofol 150 mg. Intubation was facilitated with IV succinylcholine 100 mg. Anesthesia was maintained with sevoflurane, O₂, air, and atracurium as the muscle relaxant. The right internal jugular vein was cannulated with a triple lumen catheter of size 7 French. Epidural infusion was started with 0.25% of bupivacaine at 5-6 ml/hr. Injection paracetamol 1 g IV was given for additional analgesia. Pulse oximetry, electrocardiogram, invasive blood pressure (BP), end tidal CO₂, central venous pressure (CVP), core body temperature by a nasopharyngeal probe, neuromuscular monitoring, hourly urine output and 2 hourly general random blood sugar (GRBS), and arterial blood gas (ABG) were measured.

Patient was positioned in the right lateral decubitus position. Sufficient depth was ensured before the introduction of trocar. A close watch on the hemodynamics was kept while inducing pneumoperitoneum. With the help of laparoscopes, the left kidney was mobilized. Before clamping, 100ml of 20% mannitol was given for renal protection.

Mannitol was given for renal protection. About 3 L of crystalloids (2 L Ringer lactate and 1 L sterofundin ISO solution) infused. A high CVP of 12–15 cm of H₂O was maintained. His systolic BP was maintained above 120 mm of Hg. Ureter was clipped and divided. Modified Gibson's incision was made on the left side. Left renal artery and vein clipped and divided. Kidney along with the ureter was retrieved through the incision and handed over to the perfusion team. Explanted kidney perfused with cold histidine tryptophan ketoglutarate (HTK) solution. The warm ischemia time was 1 min. Meanwhile, patient was changed over to supine position. Incision extended. Necessary specimens for histopathological examination were excised and sent. Port sites sutured.

While the bench surgery was taking place, IV fluids were restricted and CVP was reduced to 5 cm of H₂O. After dissection, the kidney was transplanted into the left iliac fossa through the same incision. The renal artery was anastomosed to external iliac artery and renal vein to external iliac vein. Clamp released. The cold ischemia time was 113 min. Just before the release of clamp, CVP was again increased to 15 cm of H₂O. His systolic BP was kept above 140 mm of Hg. He had lost around 800 ml of blood. Post transplantation about 3 L of crystalloids were infused. Injection furosemide 40 mg IV was given. There was adequate urine output of 300 ml after reperfusion. After ensuring hemostasis, they closed the incision. The surgery took around 6 h. An ABG was taken which showed no significant metabolic or electrolytic abnormalities. He was extubated uneventfully after complete reversal of muscle paralysis.

During the postoperative period, he had good diuresis. Analgesia was attained using continuous epidural infusion of 0.125% bupivacaine at 4–6 ml/h and IV paracetamol 1 g three times daily. His serum creatinine during the second postoperative day was 1.7 mg% which came down to 1.3 mg% by the 5^th postoperative day. Apart from this, his postoperative period was rather uneventful. Epidural was continued until the 5^th postoperative day after which the catheter was removed, and the patient was switched over to oral analgesics, paracetamol 650 mg four times daily and tramadol 50 mg thrice daily. On the 10^th postoperative day, he was discharged from the hospital.

DISCUSSION

Extracorporeal resection of tumor and auto transplantation of kidney is a technically demanding procedure. The difficulties and complications associated with this procedure from anesthetic and surgical point of view are grave and sometimes even life-threatening. If the surgery is undergoing in a single functioning kidney on which the patient is depended entirely, then the risks are intensified.

Bench surgery and auto transplantation consists of mainly three procedures: A nephrectomy, an extracorporeal resection/repair and the autotransplantation of the repaired kidney.[6] In our scenario, it was done under laparoscopic assistance. Hence, the challenges due to laparoscopy were kept in mind while providing anesthesia. Air was used instead of nitrous oxide.[7] A close monitoring of end tidal carbon dioxide value and airway pressure was ensured all throughout the procedure. The nephrectomy part is fairly similar to a live donor nephrectomy.[8] Our main goal during this period was to maintain adequate perfusion to the kidney. Hence, before clamping the renal artery, a high normal BP and a CVP of 12–15 cm of H₂O were ensured with the help of generous IV hydration. Mannitol was infused to protect the kidney from the impending ischemic injury.[9] After removing, the kidney was perfused with a cold preservative solution. Here, we used the HTK solution, which has got low sodium and calcium and has a powerful buffer (histidine).[10] During the bench surgery, our aim was to prevent fluid overload as the patient was basically anuric. Hence, the IV fluids were restricted. CVP kept low.[11] Just before anastomosis and release of the clamp, we increased the CVP to about 15 cm of H₂O and maintained a higher BP at 140/90 mm Hg to provide adequate perfusion to the transplanted kidney.[12] We did not resort to blood transfusion as much as possible in the light of new studies showing the association of perioperative blood transfusion with postoperative morbidity and cancer recurrence.[13,14] Similarly, we refrained from using colloids for this patient as studies have shown that it may cause renal tubular dysfunction from hyperoncotic mechanisms.[15] Furosemide was given to improve graft viability and ensure diuresis. It has been also found to bring down O₂ consumption in the renal tubules and thereby prevent any ischemic injury to the kidney.[16]

Recovery from anesthesia must be smooth. Planned postoperative ventilation may be helpful in hemodynamically unstable patients. Adequate analgesia must be ensured in the postoperative period. In our patient, we made use of the low-thoracic epidural anesthesia, which continued long into the postoperative period. A continuous and close monitoring of the patient's hemodynamic parameters and laboratory reports, along with prompt and proper intervention during the postoperative period will lead to a successful outcome following such a procedure.

Financial support and sponsorship

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Conflicts of interest

There are no conflicts of interest.