EXPERIMENTAL AND CLINICAL TRANSPLANTATION

Adequate perioperative analgesia is essential to optimize recovery in pediatric transplant surgery. Regional anesthesia techniques, such as continuous quadratus lumborum block, have been identified as effective and safe options for managing perioperative pain in pediatric abdominal surgeries. However, data on its use in pediatric kidney transplants are limited. We present a case series of 8 pediatric patients who underwent kidney transplant between January 2022 and April 2024 at our institution because of stage V chronic kidney disease of various etiologies. Four patients had received hemodialysis and 2 had received continuous ambulatory peritoneal dialysis before transplant. After induction of general anesthesia, quadratus lumborum block was performed before the surgical incision. Patients were positioned in the left lateral decubitus position. Patients had ultrasonographic imaging using the subcostal approach to visualize the lateral abdominal muscle layers. Once the psoas major muscle was identified, an 18-gauge Tuohy needle was inserted 1 to 2 cm lateral to the ultrasonograph probe, targeting the quadratus lumborum muscle. A catheter was subsequently inserted anterior to the quadratus lumborum muscle. Each patient received continuous quadratus lumborum block with either 0.125% bupivacaine at a rate of 4 to 6 mL/hour for 24 hours or 0.2% ropivacaine at a rate of 6 mL/hour as part of a multimodal perioperative pain management protocol. The perioperative pain was effectively managed with minimal need for rescue analgesics, and no substantial adverse events were reported. Quadratus lumborum block is an accessible and safe technique with great potential to facilitate postoperative pain management, especially in pediatric patients undergoing kidney transplant.

Key words : Interfascial plane block, Pain management, Pediatric renal transplant

Introduction
Pediatric kidney transplant is the preferred treatment for end-stage kidney disease in children, providing excellent outcomes and quality of life.¹ Effective perioperative management, including enhanced recovery after surgery (ERAS) protocols, is crucial for optimal results. Adequate pain management improves recovery, shortens hospital stays, reduces costs, and boosts patient satisfaction.^2,3 Since 2013, our institution’s pediatric kidney transplant program has achieved a 96% success rate in 38 living donor transplants.

Regional anesthesia is essential for management of postoperative pain in children, which can enhance outcomes and reduce opioid-related side effects. Quadratus lumborum block (QLB) offers effective analgesia for various surgeries, providing better pain relief and reducing opioid use compared with other methods in children.^4-10 However, data on safety and effectiveness of QLB in pediatric kidney transplant recipients are limited. This case series evaluates the use of ultrasonogram-guided continuous QLB as part of multimodal perioperative pain management for kidney transplant.

Case Report
Eight patients with stage V chronic kidney disease (CKD) from various etiologies underwent elective laparotomy kidney transplants from related living donors from January 2022 to April 2024 (Table 1). Most donors were parents, and some were cousins. Premedication included midazolam (0.06 mg/kg). Induction involved fentanyl (2 μg/kg), propofol (2 mg/kg), and atracurium (0.5 mg/kg) for intubation.

For the quadratus lumborum block procedure, we used a standardized protocol after anesthesia induction and before incision. Patients were positioned in the left lateral decubitus position. A low-frequency (2-6 MHz) curved array ultrasonograph transducer (4C-RS, Logic E, GE Healthcare) was used to visualize the abdominal and quadratus lumborum (QL) muscles. The subcostal approach involved placing the probe vertically. An 18G Tuohy needle (Perifix) was inserted 1 to 2 cm lateral to the probe toward the QL muscle (Figure 1). After hydrodissection with 1 mL of 0.9% sodium chloride, 20 mL of 0.25% bupivacaine was injected around the anterolateral QL muscle. A catheter was inserted anterior to the QL muscle and confirmed by vacuum aspiration. Anesthesia was maintained with 2.5% sevoflurane and 1.0 L/min fresh gas flow.

Anesthesia was terminated after surgery, and patients were then extubated in the operating room before being transferred to the pediatric intensive care unit. Postoperative monitoring included pain assessment using the Face, Legs, Activity, Cry, and Consolability (FLACC) scale (scale of 1 to 12) for patients aged 1 to 7 years and the Visual Analog Scale (VAS) (scale of 1 to 10) for patients aged 7 to 12 years; review of laboratory tests; and documentation of rescue or nonopioid analgesia use (Table 2).

Patient 1 was an 11-year-old boy with CKD stage V due to bilateral contracted kidneys. Posttransplant pain per FLACC decreased from 1 to 2 of 12 on the first 2 postoperative days (PODs) to 0 to 1 of 12 by the third POD. Blood urea and creatinine levels normalized by the second POD. He initially had hypokalemia, hypocalcemia, and hyperchloremia, followed by low sodium and potassium levels.

Patient 2 was a 14-year-old boy with CKD stage V due to bilateral kidney hypoplasia complicated by hypertension and tuberculosis. After transplant, pain per VAS was rated 1 to 2 of 10 on the first POD, following accidental catheter removal. Blood urea and creatinine levels were elevated on the first POD but normalized by the second. On the second POD, he exhibited hypokalemia, hypocalcemia, and hyperchloremia.

Patient 3 was a 15-year-old boy with CKD stage V from glomerulonephritis who received routine hemodialysis and had a kidney transplant in December 2023. Postoperatively, pain scores were consistently low (VAS of 0 to 1 of 10). Blood urea and creatinine levels were high but showed a decreasing trend. By the fourth POD, his urea level normalized, although his creatinine level, while decreasing, remained high. Pain management included intra-venous paracetamol and tramadol infusions.

Patient 4 was a 15-year-old girl with CKD stage V from nephrotic syndrome. Postoperative pain scores per VAS were 2 to 3 of 10 on the first 2 PODs, decreasing to 0 to 1 of 10 until catheter removal on the fourth POD. Laboratory results showed anemia and leukocytosis with a decreasing trend. Blood urea levels were high on the first POD but normalized subsequently. Creatinine levels remained high until catheter removal. She had hyponatremia, hypomagnesemia, hyperchloremia, and hypocalcemia during the first 3 days. No rescue analgesia was required.

Patient 5 was a 15-year-old boy with CKD stage V from bilateral contracted kidneys, who had continuous ambulatory peritoneal dialysis (CAPD). After transplant, pain scores per VAS were initially 3 to 4, decreasing after catheter removal on the third day. Laboratory results showed anemia, leukocytosis, and elevated urea levels. Because of reagent shortages, creatinine levels were not measured. He also had hyponatremia and hypokalemia. Pain management included fentanyl as rescue analgesia, along with intravenous paracetamol and tramadol infusions.

Patient 6 was a 16-year-old boy with CKD stage V after routine hemodialysis. Postoperative pain remained stable at VAS of 1 to 2 of 10 until catheter removal on the third POD. Laboratory results showed anemia and leukocytosis. On the first POD, electrolyte assessments revealed hyponatremia, hypocalcemia, and hypochloremia, which gradually normalized.

Patient 7 was a 6-year-old boy with CKD stage V from severe bilateral hydronephrosis who was on CAPD for 2 years. On the first POD, his pain score per FLACC was 2 of 12, decreasing after accidental catheter removal. Blood work showed anemia and leukocytosis, which decreased over time. Blood urea and creatinine levels were initially high but improved during the treatment period.

Patient 8 was a 16-year-old girl with CKD due to a bilateral contracted kidney and a history of hypertension. She had consistently low pain scores (VAS of 1 to 2 of 10) throughout her hospitalization. Complete blood count indicated anemia, and blood urea and creatinine levels were elevated on the first POD but decreased by the second POD.

Discussion
Management of postoperative pain in pediatric patients, particularly young children, is challenging but essential for minimizing discomfort and promoting recovery. Effective perioperative care, including ERAS protocols, involves multimodal analgesia and regional anesthesia to reduce complications, shorten hospital stays, decrease costs, and improve patient satisfaction.² In pediatric kidney transplant, analgesic options are restricted by potential toxicity, altered metabolism, and delayed clearance because of impaired kidney function. Regional anesthesia, especially fascial plane blocks, provides a safer alternative to traditional methods (epidural or spinal blocks), reducing the risk of bleeding and neural injury.⁴

Quadratus lumborum block is an ultrasonogram-guided fascial plane block where local anesthetic is injected adjacent to the QL muscle to block the thoracolumbar nerves. This procedure has shown efficacy in adult and pediatric patients undergoing various surgical procedures as part of a multimodal pain management approach.^6-13

The naming of QLB reflects the needle tip’s anatomical positioning relative to the QL muscle. Studies in decedents have shown that QLB spreads cranially, consistently affecting T7-T12 nerves, including the iliohypogastric, ilioinguinal, and subcostal nerves. No studies have yet compared anesthetic spread between adults and pediatric patients undergoing QLB. In pediatric patients, who have smaller anatomical structures and closer proximity to vital organs than adults, precise consideration of local anesthetic dosage and QLB placement techniques is essential.^11,12

A meta-analysis of QLB in pediatric patients demonstrated significant reductions in postoperative rescue analgesia rates and pain scores at 2, 4, and 12 hours.¹³ Postoperative opioid consumption was notably decreased, with several studies reporting reduced opioid requirements within the first 24 hours after surgery with QLB.^6-9 In our case series, QLB provided effective postoperative analgesia, with only 1 patient requiring rescue analgesia. Pain management through QLB led to minimal initial pain levels and a decreasing trend during recovery.

Regional blocks carry a risk of local anesthetic systemic toxicity (LAST), with the risk increasing in young patients. However, no cases of LAST due to QLB have been reported. Among our patients, electrolyte imbalances were observed, likely as a result of the large volumes of diuresis and intravenous replacements associated with the surgery.¹⁴ Of note, our study found that the choice of local anesthetic did not further impair kidney function.

Consensus has not yet been reached on the optimal volume of local anesthesia for effective analgesia with QLB in kidney transplant patients. In pediatric QLB, the volume and concentration of local anesthetic depend on patient weight, surgical procedure, desired dermatomal coverage, and provider preference. Accurate dosing based on the child’s weight is crucial to minimize LAST and other potential complications.⁵

Infection risk with QLB is low; however, a clean technique is recommended for single-shot blocks and a sterile technique for continuous infusions. Among our patients, no QLB-related leukocytosis was observed, with any instances attributed to the surgical procedure. Documented complications of QLB in adults have included lower limb weakness, sympathetic block, hematoma, and urinary retention. Although similar occurrences have been reported in pediatric patients, they have not shown statistical significance.^5,15

This study incorporated QLB into a multimodal pain management approach within an ERAS protocol, with no QLB-related complications observed. Our findings suggested that QLB is a safe and effective method for management of postoperative pain in pediatric patients undergoing kidney transplant. However, the absence of a standardized postoperative management protocol highlights the need for further research to fully assess QLB’s efficacy in this context. Despite this limitation, QLB is increasingly recognized as a favorable pain management option in pediatric surgery due to its accessibility, safety, and positive outcomes.

Conclusions
Quadratus lumborum block has become the preferred regional anesthetic technique for children undergoing kidney transplant, with effective outcomes and minimal adverse effects. This study underscored the ability of QLB to improve postoperative pain control in pediatric surgery, as evidenced by lower pain scores and decreased use of rescue analgesics. Further research is necessary to establish optimal local anesthetic dosing guidelines and to elucidate the mechanisms of QLB in pediatric patients.

Volume: 23 Issue: 1 January 2025

FULL TEXT