Anaesthesia 2014, 69, 1222–1226
doi:10.1111/anae.12704
Original Article A randomised controlled trial of ultrasound-guided transversus abdominis plane block for renal transplantation* S. M. Gulyam Kuruba,1 K. Mukhtar2 and S. K. Singh3 1 Consultant Anaesthetist, Warrington and Halton Hospital NHS Foundation Trust, Warrington, UK 2 Consultant Anaesthetist, St. Helens and Knowsley Teaching Hospitals NHS Trust, Prescot, UK 3 Consultant Anaesthetist, Royal Liverpool and Broad Green University Hospitals NHS Trust, Liverpool, UK
Summary We conducted this study to evaluate the efficacy of a transversus abdominis plane block in reducing morphine requirements in the first 24 h after renal transplant surgery. We performed transversus abdominis plane injections under ultrasound guidance in 54 patients with either 20 ml levobupivacaine 0.5% (n = 27) or 20 ml saline 0.9% (n = 27). All patients received regular paracetamol and patient-controlled analgesia postoperatively. Three participants were not studied owing to protocol violations. In the remaining 51 patients, median (IQR [range]) morphine consumption in the first 24 h was similar in both the transversus abdominis plane group (19.4 (11.7 28.6 [0.5 49.8]) mg) and the control group (16.4 (12.0 31.0 [0.0 61.7]) mg), p = 0.94. We found that use of ultrasound-guided transversus abdominis plane block for renal transplantation did not reduce 24-h morphine requirements. .................................................................................................................................................................
Correspondence to: S. M. Gulyam Kuruba Email: [email protected] *Presented in part to the Anaesthetic Research Society, Liverpool, UK; June 2011. Accepted: 21 March 2014
Introduction Postoperative pain after renal transplantation surgery may be severe, but analgesic options are limited. When administering analgesics to patients with impaired renal function, the effect of altered clearance, the production and accumulation of active metabolites and the risk of aggravating pre-existing kidney disease must be considered [1]. Intravenous opioids are the most common analgesics used in renal transplant units in the UK [2], although respiratory depression resulting from accumulation of morphine metabolites is a risk, even with adequate graft perfusion [3]. As a substantial part of the pain experienced after renal transplantation originates from the abdominal 1222
wall incision, which is innervated by intercostal nerves that pass through the transversus abdominis plane (TAP), this study was conducted to evaluate the efficacy of a TAP block in reducing morphine requirements in the first 24 h after renal transplant surgery.
Methods This clinical trial was registered on clinicaltrials.gov (registration no. NCT 00905957). After obtaining approval from the Northwest Research Ethics Committee and written informed consent from the patients, 54 patients undergoing renal transplantation were included in this randomised blinded study. Patients with a history of local anaesthetic allergy or chronic opioid usage and those who had taken part in another © 2014 The Association of Anaesthetists of Great Britain and Ireland
Gulyam Kuruba et al. | TAP block for renal transplantation
interventional study in the past 30 days were excluded from the study. We randomly allocated 27 participants to receive a TAP injection with levobupivacaine 0.5% and 27 participants to receive saline 0.9% by computer-generated numbers (Minim, York trial Unit) in opaque, sealed envelopes. The investigator performing the blocks, participants, staff providing postoperative care and statisticians were all blinded to the assigned groups. All patients received a standardised general anaesthetic and were monitored according to published guidelines [4]. Anaesthesia was induced with fentanyl 1–2 lg.kg 1 and propofol 2–3 mg.kg 1. Tracheal intubation was facilitated with atracurium 0.5 mg.kg 1. A unilateral ultrasound-guided TAP block was performed after induction of anaesthesia, with either 20 ml levobupivacaine 0.5% or 20 ml saline 0.9%. The injectate was separately prepared by an anaesthetist not involved in the direct care of the participant at any point during the peri-operative period. All the TAP blocks were performed under ultrasound guidance. After skin disinfection with 0.5% chlorhexidine solution, a high-frequency linear array ultrasound transducer (SonoSite Micromax; SonoSite, Inc., Bothwell, MO, USA) was placed transverse to the abdominal wall between the lower costal margin and the iliac crest to provide a view of the abdominal wall muscles. An 80-mm insulated needle (Pajunk, Geisingen, Germany) was introduced in plane of the ultrasound beam and advanced until it reached the plane between the internal oblique and transversus abdominis muscles. On entering the fascial plane, the operator injected the local anaesthetic or saline after confirming negative aspiration, and viewed the injectate spread as an expanding hypo-echoic plane under the internal oblique fascia. Intra-operative analgesia consisted of intravenous paracetamol 1 g and morphine up to 0.1 mg.kg 1 at the discretion of the anaesthetist looking after the patient. In our institution, the surgeons use a standard Rutherford-Morrison incision for renal transplantation, extending from above the symphysis pubis to around 2 cm above and medial to the anterior superior iliac spine. The external oblique aponeurosis is opened and the internal and transversalis fascia divided to allow access to the retroperitoneal vessels. As most of the © 2014 The Association of Anaesthetists of Great Britain and Ireland
Anaesthesia 2014, 69, 1222–1226
surgery is extra-peritoneal, the T10-L1 cover provided by a TAP block should be ideal for this surgical procedure. After completion of the surgery, patients were transferred to the postoperative recovery area. All patients received intravenous paracetamol 1 g every 6 h, and patient-controlled analgesia delivering intravenous morphine 0.5 mg every 10 min on demand. Rescue antiemetics were administered as and when required. The primary outcome measure was morphine consumption in the first 24 h after surgery. Secondary outcomes included assessment of pain scores, the degree of nausea and vomiting, sedation, respiratory depression and pruritis. Visual analogue pain scores (VAS 0–10) were measured by nursing staff blinded to group allocation, in theatre recovery, and at 3, 6, 12 and 24 h postoperatively on the ward. Postoperative nausea and vomiting was measured using a categorical scoring system (none, 0; mild, 1; moderate, 2; and severe, 3). Sedation was measured using a categorical scoring system (none, 0; mild, 1; moderate, 2; severe, 3 and sleep, S). We also recorded the incidence of respiratory depression (respiratory rate < 8 min 1) and of pruritus. We estimated that a sample size of 54 participants would be required (with less than a 15% drop-out) to have 80% power to detect a reduction in morphine consumption in the first 24 h of 0.8 mg at a two-tailed significance of 0.05, assuming a mean (SD) control group consumption of 28.9 (6.0) mg. The control morphine consumption was based on our transplant database and a previous pilot study [5]. As pain description consists of ordered categories rather than a true interval scale, we used a Kruskal– Wallis test to assess differences in pain scores between the two groups, and a proportional odds model with robust standard errors to allow for the clustered nature of the data. We used the Mann–Whitney U-test to analyse morphine consumption, which was not normally distributed. The intra-operative fentanyl and morphine requirements, as well as morphine requirements in recovery, were compared using Student’s t-test after log transformation. We compared categorical data using Fisher’s exact test. Statistical analysis was performed using STATA version 12 [6]. 1223
Anaesthesia 2014, 69, 1222–1226
Gulyam Kuruba et al. | TAP block for renal transplantation
Results We recruited 54 participants, three of whom were subsequently excluded due to protocol violations: one underwent further surgery within 24 h for renal vein thrombosis; one was taken back to theatre from recovery for operative site bleeding; and one decided to withdraw from the study. Of the remaining 51 participants, 24 received levobupivacaine 0.5% and 27 received saline 0.5% for TAP injections. Participants who received levobupivacaine were similar to those who received saline with regard to mean (SD) age (51.3 (14.5) and 50.1 (13.5) years, respectively) and sex (male:female ratio 12:12 and 18:9, respectively). There was no statistical difference at any point in either opioid consumption (Table 1 and Fig. 1) or pain scores (Fig. 2), odds ratio (95% CI) 1.61 (0.7–3.7), p = 0.26. There was no statistical difference between groups in the incidence of sedation (at 3 h: p = 0.26; 6 h: p = 0.35; 12 h: p = 0.49; 24 h: p = 0.49) and nausea and vomiting (p = 0.47). There was no incidence of pruritus in both groups.
Discussion Pain control after renal transplantation can be challenging, as analgesics in common use such as opioids and non-steroidal anti-inflammatory drugs (NSAIDs) owing to impaired renal function and altered pharmacokinetics. Use of morphine in patients with chronic kidney disease can result in accumulation of morphine-6-glucoronide, potentially causing delayed onset of sedation and respiratory depression. Alternatives such as NSAIDs are nephrotoxic agents that precipitate an acute decrease in glomerular filtration rate, and result in increased risk of cardiovascular and gastrointestinal complications [1].
The use of central neuroaxial blocks is controversial because of possible deranged coagulation in chronic renal failure and the haemodynamic changes that may affect graft function, but a combination of ilioinguinal-iliohypogastric and intercostal nerves co-blockade has been described, with promising results [7]. The use of TAP blocks has increased over the last few years, with multiple trials showing that they provide good pain relief after various abdominal surgical procedures [8–11]. There is controversy in the literature regarding the spread of local anaesthetic after a TAP injection, with earlier landmark techniques showing a much wider spread compared with ultrasoundguided techniques. A recent volunteer study showed that an ultrasound-guided TAP block performed at the mid-axillary line between the costal margin and iliac crest will only involve the lower thoracic and upper lumbar nerve roots (approximately T10-L1) [12]. This mirrors the results from a previous cadaveric study [13]. In a similar study by Freir et al. [14], TAP block performed using the landmark technique in patients undergoing renal transplantation did not reduce postoperative morphine requirements, and they suggested the use of ultrasound-guided technique to improve the success rate of the block. In the current study, despite the use of ultrasound guidance, the block did not show the anticipated morphine-sparing effect in the study group which was demonstrated in our previous pilot study [5]. The difference in morphine requirements between TAP and control groups was neither clinically nor statistically significant. This raises the question of optimum timing of the block. In our study, the blocks were performed within 30 min or less of the surgical incision, after induction of anaesthesia, whilst central venous access was being obtained. This may have led to loss of the local
Table 1 Peri-operative fentanyl and morphine consumption in patients receiving transversus abdominis plane blocks with levobupivacaine (TAP) or saline (control). Values are mean (SD) or mean (95% CI).
Intra-operative fentanyl;* lg Intra-operative morphine;* mg
TAP (n = 24)
Control (n = 27)
Difference
p value
4.53 (0.35) 1.76 (0.45)
4.56 (0.23) 1.76 (0.30)
0.03 [ 0.13, 0.20] 0.003 [ 0.22, 0.22]
0.69 0.98
*Natural logarithm transformation. 1224
© 2014 The Association of Anaesthetists of Great Britain and Ireland
Gulyam Kuruba et al. | TAP block for renal transplantation
Anaesthesia 2014, 69, 1222–1226
Figure 1 Morphine consumption in patients receiving transversus abdominis plane blocks with levobupivacaine (TAP) or saline (control), at different postoperative time points. Horizontal line, median; box, IQR; upper and lower whiskers, the largest data values lower or equal to the third quartile plus IQR 9 1.5, or the smallest data values greater than or equal to the first quartile minus IQR 9 1.5, respectively. The box is median (IQR). The whiskers at the top represent the upper adjacent limits, which are the largest data values that are lower or equal to the third quartile plus 1.5 9 IQR, while the whiskers at the bottom represent the lower adjacent limits, which are the smallest data values that are greater than or equal to the first quartile minus 1.5 9 IQR.
Figure 2 Mean pain scores (visual analogue score 0–10) over time in patients receiving transversus abdominis plane blocks with levobupivacaine ( ) or saline ( ). Error bars are SD. anaesthetic in the surgical field, as the surgery involves dissection into the TAP. The short interval between performing the block and surgical incision may have © 2014 The Association of Anaesthetists of Great Britain and Ireland
prevented sufficient time for full absorption and distribution of the local anaesthetic, hence leading to a shorter duration of action, and a less pronounced 1225
Anaesthesia 2014, 69, 1222–1226
effect. Placement of an indwelling catheter in the TAP and administration of the local anaesthetic as a continuous infusion should also be considered, as shown by Jankovic et al. [15]. However, this has to be weighed against the risk of introducing infection in these immunosuppressed patients. Another limitation of our study is that we did not assess the sensory distribution of the TAP block in recovery. This was for two reasons: Firstly, this may have unmasked the blinding to the recovery staff, and may have introduced bias towards the administration of more analgesics in the control group during the patients’ stay in recovery. Secondly, it has been proposed that there is poor correlation between spread of the injectate in the TAP and the level of sensory block [11]. In conclusion, we found no evidence to suggest that ultrasound-guided TAP blocks reduced morphine requirements in renal transplant recipients in the first 24 h after surgery. Further trials are warranted to address the ideal timing of the block and the use of continuous catheter infusions in this cohort of patients.
Acknowledgements We thank the renal transplant team at the Royal Liverpool and Broadgreen University Hospital. Also we thank Eftychia-Eirini Psarelli, Statistician in Medical Statistics, Cancer Research UK Liverpool Cancer Trials Unit, Liverpool, for statistical advice.
Competing interests No external funding and no competing interests declared.
References 1. Craig RG, Hunter JM. Recent developments in the perioperative management of adult patients with chronic kidney disease. British Journal of Anaesthesia 2008; 101: 296–310.
1226
Gulyam Kuruba et al. | TAP block for renal transplantation 2. Williams M, Milner QJW. Postoperative analgesia following renal transplantation-current practice in the UK. Anaesthesia 2003; 58: 712–3. 3. Lemmens HJM. Kidney transplantation: recent developments and recommendations for anaesthetic management. Anesthesiology Clinics of North America 2004; 22: 651–62. 4. Association of Anaesthetists of Great Britain and Ireland. Recommendations for Standards of Monitoring During Anaesthesia and Recovery. London: AAGBI, 2007. 5. Mukhtar K, Khattak I. Transversus abdominis plane block for renal transplant recipients. British Journal of Anaesthesia 2010; 104: 663–4. 6. StataCorp. STATA v12: Stata Statistical Software Release 12.0. College Station, TX: StataCorp, 2011. 7. Shoeibi G, Babakhani B, Mohammadi SS. The efficacy of ilioinguinal-iliohypogastric and intercostal nerve co-blockade for postoperative pain relief in kidney recipients. Anesthesia and Analgesia 2009; 108: 330–3. 8. McDonnell JG, O’Donnell B, Curley G, Heffernan A, Power C, Laffey JG. The analgesic efficacy of transversus abdominis plane block after abdominal surgery: a prospective randomized controlled trial. Anesthesia and Analgesia 2007; 104: 193–7. 9. Carney J, McDonnell JG, Ochana A, Bhinder R, Laffey JG. The transversus abdominis plane block provides effective postoperative analgesia in patients undergoing total abdominal hysterectomy. Anesthesia and Analgesia 2008; 107: 2056–60. 10. Aveline C, Le Hetet H, Le Roux A, et al. Comparison between ultrasound-guided transversus abdominis plane and conventional ilioinguinal/iliohypogastric nerve blocks for day-case open inguinal hernia repair. British Journal of Anaesthesia 2011; 106: 380–6. 11. Belvay D, Cowlishaw PJ, Howes M, Phillips F. Ultrasoundguided transversus abdominis plane block for analgesia after caesarean delivery. British Journal of Anaesthesia 2009; 103: 726–30. 12. Carney J, Finnerty O, Rauf J, Bergin D, Laffey JG, McDonnell JG. Studies on the spread of local anaesthetic solution in transversus abdominis plane blocks. Anaesthesia 2011; 66: 1023– 30. 13. Tran TMN, Ivasunic JJ, Hebbard P, Barrington MJ. Determination of spread of injectate after ultrasound-guided transverses abdominis plane block: a cadaveric study. British Journal of Anaesthesia 2009; 102: 123–7. 14. Freir NM, Murphy C, Mugawar M, Linnane A, Cunningham AJ. Transversus abdominis plane block for analgesia in renal transplantation: a randomized controlled trial. Anesthesia and Analgesia 2012; 115: 953–7. 15. Jankovic ZB, Pollard SG, Nachiappan MM. Continuous transversus abdominis plane block for renal transplant recipients. Anesthesia and Analgesia 2009; 109: 1710–1.
© 2014 The Association of Anaesthetists of Great Britain and Ireland
doi:10.1111/anae.12704
Original Article A randomised controlled trial of ultrasound-guided transversus abdominis plane block for renal transplantation* S. M. Gulyam Kuruba,1 K. Mukhtar2 and S. K. Singh3 1 Consultant Anaesthetist, Warrington and Halton Hospital NHS Foundation Trust, Warrington, UK 2 Consultant Anaesthetist, St. Helens and Knowsley Teaching Hospitals NHS Trust, Prescot, UK 3 Consultant Anaesthetist, Royal Liverpool and Broad Green University Hospitals NHS Trust, Liverpool, UK
Summary We conducted this study to evaluate the efficacy of a transversus abdominis plane block in reducing morphine requirements in the first 24 h after renal transplant surgery. We performed transversus abdominis plane injections under ultrasound guidance in 54 patients with either 20 ml levobupivacaine 0.5% (n = 27) or 20 ml saline 0.9% (n = 27). All patients received regular paracetamol and patient-controlled analgesia postoperatively. Three participants were not studied owing to protocol violations. In the remaining 51 patients, median (IQR [range]) morphine consumption in the first 24 h was similar in both the transversus abdominis plane group (19.4 (11.7 28.6 [0.5 49.8]) mg) and the control group (16.4 (12.0 31.0 [0.0 61.7]) mg), p = 0.94. We found that use of ultrasound-guided transversus abdominis plane block for renal transplantation did not reduce 24-h morphine requirements. .................................................................................................................................................................
Correspondence to: S. M. Gulyam Kuruba Email: [email protected] *Presented in part to the Anaesthetic Research Society, Liverpool, UK; June 2011. Accepted: 21 March 2014
Introduction Postoperative pain after renal transplantation surgery may be severe, but analgesic options are limited. When administering analgesics to patients with impaired renal function, the effect of altered clearance, the production and accumulation of active metabolites and the risk of aggravating pre-existing kidney disease must be considered [1]. Intravenous opioids are the most common analgesics used in renal transplant units in the UK [2], although respiratory depression resulting from accumulation of morphine metabolites is a risk, even with adequate graft perfusion [3]. As a substantial part of the pain experienced after renal transplantation originates from the abdominal 1222
wall incision, which is innervated by intercostal nerves that pass through the transversus abdominis plane (TAP), this study was conducted to evaluate the efficacy of a TAP block in reducing morphine requirements in the first 24 h after renal transplant surgery.
Methods This clinical trial was registered on clinicaltrials.gov (registration no. NCT 00905957). After obtaining approval from the Northwest Research Ethics Committee and written informed consent from the patients, 54 patients undergoing renal transplantation were included in this randomised blinded study. Patients with a history of local anaesthetic allergy or chronic opioid usage and those who had taken part in another © 2014 The Association of Anaesthetists of Great Britain and Ireland
Gulyam Kuruba et al. | TAP block for renal transplantation
interventional study in the past 30 days were excluded from the study. We randomly allocated 27 participants to receive a TAP injection with levobupivacaine 0.5% and 27 participants to receive saline 0.9% by computer-generated numbers (Minim, York trial Unit) in opaque, sealed envelopes. The investigator performing the blocks, participants, staff providing postoperative care and statisticians were all blinded to the assigned groups. All patients received a standardised general anaesthetic and were monitored according to published guidelines [4]. Anaesthesia was induced with fentanyl 1–2 lg.kg 1 and propofol 2–3 mg.kg 1. Tracheal intubation was facilitated with atracurium 0.5 mg.kg 1. A unilateral ultrasound-guided TAP block was performed after induction of anaesthesia, with either 20 ml levobupivacaine 0.5% or 20 ml saline 0.9%. The injectate was separately prepared by an anaesthetist not involved in the direct care of the participant at any point during the peri-operative period. All the TAP blocks were performed under ultrasound guidance. After skin disinfection with 0.5% chlorhexidine solution, a high-frequency linear array ultrasound transducer (SonoSite Micromax; SonoSite, Inc., Bothwell, MO, USA) was placed transverse to the abdominal wall between the lower costal margin and the iliac crest to provide a view of the abdominal wall muscles. An 80-mm insulated needle (Pajunk, Geisingen, Germany) was introduced in plane of the ultrasound beam and advanced until it reached the plane between the internal oblique and transversus abdominis muscles. On entering the fascial plane, the operator injected the local anaesthetic or saline after confirming negative aspiration, and viewed the injectate spread as an expanding hypo-echoic plane under the internal oblique fascia. Intra-operative analgesia consisted of intravenous paracetamol 1 g and morphine up to 0.1 mg.kg 1 at the discretion of the anaesthetist looking after the patient. In our institution, the surgeons use a standard Rutherford-Morrison incision for renal transplantation, extending from above the symphysis pubis to around 2 cm above and medial to the anterior superior iliac spine. The external oblique aponeurosis is opened and the internal and transversalis fascia divided to allow access to the retroperitoneal vessels. As most of the © 2014 The Association of Anaesthetists of Great Britain and Ireland
Anaesthesia 2014, 69, 1222–1226
surgery is extra-peritoneal, the T10-L1 cover provided by a TAP block should be ideal for this surgical procedure. After completion of the surgery, patients were transferred to the postoperative recovery area. All patients received intravenous paracetamol 1 g every 6 h, and patient-controlled analgesia delivering intravenous morphine 0.5 mg every 10 min on demand. Rescue antiemetics were administered as and when required. The primary outcome measure was morphine consumption in the first 24 h after surgery. Secondary outcomes included assessment of pain scores, the degree of nausea and vomiting, sedation, respiratory depression and pruritis. Visual analogue pain scores (VAS 0–10) were measured by nursing staff blinded to group allocation, in theatre recovery, and at 3, 6, 12 and 24 h postoperatively on the ward. Postoperative nausea and vomiting was measured using a categorical scoring system (none, 0; mild, 1; moderate, 2; and severe, 3). Sedation was measured using a categorical scoring system (none, 0; mild, 1; moderate, 2; severe, 3 and sleep, S). We also recorded the incidence of respiratory depression (respiratory rate < 8 min 1) and of pruritus. We estimated that a sample size of 54 participants would be required (with less than a 15% drop-out) to have 80% power to detect a reduction in morphine consumption in the first 24 h of 0.8 mg at a two-tailed significance of 0.05, assuming a mean (SD) control group consumption of 28.9 (6.0) mg. The control morphine consumption was based on our transplant database and a previous pilot study [5]. As pain description consists of ordered categories rather than a true interval scale, we used a Kruskal– Wallis test to assess differences in pain scores between the two groups, and a proportional odds model with robust standard errors to allow for the clustered nature of the data. We used the Mann–Whitney U-test to analyse morphine consumption, which was not normally distributed. The intra-operative fentanyl and morphine requirements, as well as morphine requirements in recovery, were compared using Student’s t-test after log transformation. We compared categorical data using Fisher’s exact test. Statistical analysis was performed using STATA version 12 [6]. 1223
Anaesthesia 2014, 69, 1222–1226
Gulyam Kuruba et al. | TAP block for renal transplantation
Results We recruited 54 participants, three of whom were subsequently excluded due to protocol violations: one underwent further surgery within 24 h for renal vein thrombosis; one was taken back to theatre from recovery for operative site bleeding; and one decided to withdraw from the study. Of the remaining 51 participants, 24 received levobupivacaine 0.5% and 27 received saline 0.5% for TAP injections. Participants who received levobupivacaine were similar to those who received saline with regard to mean (SD) age (51.3 (14.5) and 50.1 (13.5) years, respectively) and sex (male:female ratio 12:12 and 18:9, respectively). There was no statistical difference at any point in either opioid consumption (Table 1 and Fig. 1) or pain scores (Fig. 2), odds ratio (95% CI) 1.61 (0.7–3.7), p = 0.26. There was no statistical difference between groups in the incidence of sedation (at 3 h: p = 0.26; 6 h: p = 0.35; 12 h: p = 0.49; 24 h: p = 0.49) and nausea and vomiting (p = 0.47). There was no incidence of pruritus in both groups.
Discussion Pain control after renal transplantation can be challenging, as analgesics in common use such as opioids and non-steroidal anti-inflammatory drugs (NSAIDs) owing to impaired renal function and altered pharmacokinetics. Use of morphine in patients with chronic kidney disease can result in accumulation of morphine-6-glucoronide, potentially causing delayed onset of sedation and respiratory depression. Alternatives such as NSAIDs are nephrotoxic agents that precipitate an acute decrease in glomerular filtration rate, and result in increased risk of cardiovascular and gastrointestinal complications [1].
The use of central neuroaxial blocks is controversial because of possible deranged coagulation in chronic renal failure and the haemodynamic changes that may affect graft function, but a combination of ilioinguinal-iliohypogastric and intercostal nerves co-blockade has been described, with promising results [7]. The use of TAP blocks has increased over the last few years, with multiple trials showing that they provide good pain relief after various abdominal surgical procedures [8–11]. There is controversy in the literature regarding the spread of local anaesthetic after a TAP injection, with earlier landmark techniques showing a much wider spread compared with ultrasoundguided techniques. A recent volunteer study showed that an ultrasound-guided TAP block performed at the mid-axillary line between the costal margin and iliac crest will only involve the lower thoracic and upper lumbar nerve roots (approximately T10-L1) [12]. This mirrors the results from a previous cadaveric study [13]. In a similar study by Freir et al. [14], TAP block performed using the landmark technique in patients undergoing renal transplantation did not reduce postoperative morphine requirements, and they suggested the use of ultrasound-guided technique to improve the success rate of the block. In the current study, despite the use of ultrasound guidance, the block did not show the anticipated morphine-sparing effect in the study group which was demonstrated in our previous pilot study [5]. The difference in morphine requirements between TAP and control groups was neither clinically nor statistically significant. This raises the question of optimum timing of the block. In our study, the blocks were performed within 30 min or less of the surgical incision, after induction of anaesthesia, whilst central venous access was being obtained. This may have led to loss of the local
Table 1 Peri-operative fentanyl and morphine consumption in patients receiving transversus abdominis plane blocks with levobupivacaine (TAP) or saline (control). Values are mean (SD) or mean (95% CI).
Intra-operative fentanyl;* lg Intra-operative morphine;* mg
TAP (n = 24)
Control (n = 27)
Difference
p value
4.53 (0.35) 1.76 (0.45)
4.56 (0.23) 1.76 (0.30)
0.03 [ 0.13, 0.20] 0.003 [ 0.22, 0.22]
0.69 0.98
*Natural logarithm transformation. 1224
© 2014 The Association of Anaesthetists of Great Britain and Ireland
Gulyam Kuruba et al. | TAP block for renal transplantation
Anaesthesia 2014, 69, 1222–1226
Figure 1 Morphine consumption in patients receiving transversus abdominis plane blocks with levobupivacaine (TAP) or saline (control), at different postoperative time points. Horizontal line, median; box, IQR; upper and lower whiskers, the largest data values lower or equal to the third quartile plus IQR 9 1.5, or the smallest data values greater than or equal to the first quartile minus IQR 9 1.5, respectively. The box is median (IQR). The whiskers at the top represent the upper adjacent limits, which are the largest data values that are lower or equal to the third quartile plus 1.5 9 IQR, while the whiskers at the bottom represent the lower adjacent limits, which are the smallest data values that are greater than or equal to the first quartile minus 1.5 9 IQR.
Figure 2 Mean pain scores (visual analogue score 0–10) over time in patients receiving transversus abdominis plane blocks with levobupivacaine ( ) or saline ( ). Error bars are SD. anaesthetic in the surgical field, as the surgery involves dissection into the TAP. The short interval between performing the block and surgical incision may have © 2014 The Association of Anaesthetists of Great Britain and Ireland
prevented sufficient time for full absorption and distribution of the local anaesthetic, hence leading to a shorter duration of action, and a less pronounced 1225
Anaesthesia 2014, 69, 1222–1226
effect. Placement of an indwelling catheter in the TAP and administration of the local anaesthetic as a continuous infusion should also be considered, as shown by Jankovic et al. [15]. However, this has to be weighed against the risk of introducing infection in these immunosuppressed patients. Another limitation of our study is that we did not assess the sensory distribution of the TAP block in recovery. This was for two reasons: Firstly, this may have unmasked the blinding to the recovery staff, and may have introduced bias towards the administration of more analgesics in the control group during the patients’ stay in recovery. Secondly, it has been proposed that there is poor correlation between spread of the injectate in the TAP and the level of sensory block [11]. In conclusion, we found no evidence to suggest that ultrasound-guided TAP blocks reduced morphine requirements in renal transplant recipients in the first 24 h after surgery. Further trials are warranted to address the ideal timing of the block and the use of continuous catheter infusions in this cohort of patients.
Acknowledgements We thank the renal transplant team at the Royal Liverpool and Broadgreen University Hospital. Also we thank Eftychia-Eirini Psarelli, Statistician in Medical Statistics, Cancer Research UK Liverpool Cancer Trials Unit, Liverpool, for statistical advice.
Competing interests No external funding and no competing interests declared.
References 1. Craig RG, Hunter JM. Recent developments in the perioperative management of adult patients with chronic kidney disease. British Journal of Anaesthesia 2008; 101: 296–310.
1226
Gulyam Kuruba et al. | TAP block for renal transplantation 2. Williams M, Milner QJW. Postoperative analgesia following renal transplantation-current practice in the UK. Anaesthesia 2003; 58: 712–3. 3. Lemmens HJM. Kidney transplantation: recent developments and recommendations for anaesthetic management. Anesthesiology Clinics of North America 2004; 22: 651–62. 4. Association of Anaesthetists of Great Britain and Ireland. Recommendations for Standards of Monitoring During Anaesthesia and Recovery. London: AAGBI, 2007. 5. Mukhtar K, Khattak I. Transversus abdominis plane block for renal transplant recipients. British Journal of Anaesthesia 2010; 104: 663–4. 6. StataCorp. STATA v12: Stata Statistical Software Release 12.0. College Station, TX: StataCorp, 2011. 7. Shoeibi G, Babakhani B, Mohammadi SS. The efficacy of ilioinguinal-iliohypogastric and intercostal nerve co-blockade for postoperative pain relief in kidney recipients. Anesthesia and Analgesia 2009; 108: 330–3. 8. McDonnell JG, O’Donnell B, Curley G, Heffernan A, Power C, Laffey JG. The analgesic efficacy of transversus abdominis plane block after abdominal surgery: a prospective randomized controlled trial. Anesthesia and Analgesia 2007; 104: 193–7. 9. Carney J, McDonnell JG, Ochana A, Bhinder R, Laffey JG. The transversus abdominis plane block provides effective postoperative analgesia in patients undergoing total abdominal hysterectomy. Anesthesia and Analgesia 2008; 107: 2056–60. 10. Aveline C, Le Hetet H, Le Roux A, et al. Comparison between ultrasound-guided transversus abdominis plane and conventional ilioinguinal/iliohypogastric nerve blocks for day-case open inguinal hernia repair. British Journal of Anaesthesia 2011; 106: 380–6. 11. Belvay D, Cowlishaw PJ, Howes M, Phillips F. Ultrasoundguided transversus abdominis plane block for analgesia after caesarean delivery. British Journal of Anaesthesia 2009; 103: 726–30. 12. Carney J, Finnerty O, Rauf J, Bergin D, Laffey JG, McDonnell JG. Studies on the spread of local anaesthetic solution in transversus abdominis plane blocks. Anaesthesia 2011; 66: 1023– 30. 13. Tran TMN, Ivasunic JJ, Hebbard P, Barrington MJ. Determination of spread of injectate after ultrasound-guided transverses abdominis plane block: a cadaveric study. British Journal of Anaesthesia 2009; 102: 123–7. 14. Freir NM, Murphy C, Mugawar M, Linnane A, Cunningham AJ. Transversus abdominis plane block for analgesia in renal transplantation: a randomized controlled trial. Anesthesia and Analgesia 2012; 115: 953–7. 15. Jankovic ZB, Pollard SG, Nachiappan MM. Continuous transversus abdominis plane block for renal transplant recipients. Anesthesia and Analgesia 2009; 109: 1710–1.
© 2014 The Association of Anaesthetists of Great Britain and Ireland
