- Email: [email protected]
Transversus abdominis plane blocks and liver injury
Correspondence
doi:10.1093/bja/aeq102
Transversus abdominis plane blocks and liver injury Editor—We are surprised to learn that a liver injury can occur from a transversus abdominis plane (TAP) block for hernia surgery with the use of ultrasound (US).1 We notice that the authors have used Sonosite i-look US, which in our opinion is inappropriate for performing such blocks. The resolution of this machine is very poor and the screen is so small that as the depth is increased, the window becomes increasingly smaller making it difficult to properly identify the anatomical structures and the needle. We agree that more and more people are doing TAP blocks but these blocks should only be done under supervision and by people who have training in using US for nerve blocks. For liver injury to occur from a TAP block for inguinal hernia repair, there can be only two reasons: (i) the operator was unable to identify the anatomy appropriately and was in a wrong place (too high); and (ii) the operator was unable to identify the tip of the needle (which is impossible with i-look). We do, and teach our trainees to do, TAP blocks and with the numbers we have done, have yet to see a major complication like this. We appreciate the authors’ contribution in highlighting this complication but would recommend that these blocks
should only be performed after adequate training and with the use of appropriate equipment.2 S. K. Singh * J. F. Corbett Liverpool, UK *E-mail: [email protected]
Editor—We read with great interest the case report of US-guided TAP block causing liver trauma1 in a patient undergoing an inguinal hernia repair. It is evident that this block which is considered simple and effective can have significant morbidity as was seen in this case. We wish to raise several points about TAP blocks and the use of US for this procedure. (1) The patient had a bilateral TAP block for the repair of strangulated inguinal hernia and umbilical hernia. Perhaps, it would have been useful to know whether the block was done using an in-plane approach or out-of-plane approach. We advocate an in-plane approach when performing US-guided TAP blocks as we believe that this allows easier visualization of the muscle layers and needle tip position. (2) We believe the key issue with this case was that the machine used to guide the procedure was designed for visualization of vascular structures, not for imaging of the abdominal wall, and as this case illustrates, the images produced are not adequate for use in the placement of US-guided TAP blocks. Visualization of the muscle layers of the abdominal wall can be difficult, and in our institution, TAP blocks are placed using higher resolution machines and the i-look machines are only used to guide vascular access. (3) The introduction of a new procedure requires appropriate training and the complication reported appears to be related more to the ability to identify the location of the needle tip rather than the block. (4) In a recent editorial3 on TAP blocks in this journal, it was highlighted that most of the studies published so far have been on a small number of patients and they are insufficient for the evaluation of safety and efficacy of TAP blocks. In addition to this case report, there have been other case reports4 highlighting the problems of TAP block including femoral nerve paresis.5 Hence, the TAP block should be used with caution in day-case procedures if no facilities exist for overnight admission and the patients are informed of these risks.
K. Bhatia * J. Corcoran Salford, UK *E-mail: [email protected]
782
Downloaded from http://bja.oxfordjournals.org/ at Kokusai Hoken Keikakugaku (UNIV OF TOKYO) on June 13, 2015
in infants following surgery for congenital heart disease. Pediatr Crit Care Med 2008; 9: 123– 4 8 Petrova A, Mehta R. Near-infrared spectroscopy in the detection of regional tissue oxygenation during hypoxic events in preterm infants undergoing critical care. Pediatr Crit Care Med 2006; 7: 449 – 54 9 Chertow GM, Levy EM, Hammermeister KE, Grover F, Daley J. Independent association between acute renal failure and mortality following cardiac surgery. Am J Med 1998; 104: 343 – 8 10 Mangano CM, Diamondstone LS, Ramsay JG, Aggarwal A, Herskowitz A, Mangano DT. Renal dysfunction after myocardial revascularization: risk factors, adverse outcomes, and hospital resource utilization. The Multicenter Study of Perioperative Ischemia Research Group. Ann Intern Med 1998; 128: 194– 203 11 Murkin JM, Adams SJ, Novick RJ, et al. Monitoring brain oxygen saturation during coronary bypass surgery: a randomized, prospective study. Anesth Analg 2007; 104: 51 – 8 12 Doerschug KC, Delsing AS, Schmidt GA, Haynes WG. Impairments in microvascular reactivity are related to organ failure in human sepsis. Am J Physiol Heart Circ Physiol 2007; 293: H1065–71 13 Donati A, Romanelli M, Botticelli L, et al. Recombinant activated protein C treatment improves tissue perfusion and oxygenation in septic patients measured by near-infrared spectroscopy. Crit Care 2009; 13(Suppl. 5): S12 14 Smith J, Bricker S, Putnam B. Tissue oxygen saturation predicts the need for early blood transfusion in trauma patients. Am Surg 2008; 74: 1006 – 11
Correspondence
Conflict of interest None declared. P. S. Lancaster * M. Chadwick Manchester, UK *E-mail: [email protected]
1 Lancaster P, Chadwick M. Liver trauma secondary to ultrasoundguided transversus abdominis plane block. Br J Anaesth 2010; 104: 509 – 10 2 Hargett MJ, Beckman JD, Liguori GA, et al. Guidelines for fellowship training in regional anesthesia Reg Anesth Pain Med 2005; 30: 218 3 Bonnet F, Berger J, Aveline C. Transversus abdominis plane block: what is its role in postoperative analgesia? Br J Anaesth 2009; 103: 468 – 70 4 Farooq M, Carey M. A case of liver trauma with a blunt regional anesthesia needle while performing transversus abdominis plane block. Reg Anesth Pain Med 2008; 33: 274 5 Walker G. Transversus abdominis plane block: a note of caution! Br J Anaesth 2010; 104: 265 doi:10.1093/bja/aeq103
Minimum effective bolus dose of oxytocin during elective Caesarean delivery Editor—I read with great interest the article by Butwick and colleagues1 regarding the determination of the lowest effective bolus dose of oxytocin to achieve adequate uterine tone during elective Caesarean section. The authors state that exteriorization of the uterus was performed at the discretion
of the obstetrician and that subsequent uterine massage was performed. It is not clear however whether exteriorization was routinely performed or whether the uterine massage occurred on some occasions with the uterus having not been exteriorized. If exteriorization rates varied between the groups involved then this could potentially be a confounding factor affecting oxytocin delivery to the uterus and the obstetricians’ ability to both perform uterine massage and assess uterine tone adequately. Varying rates of uterine exteriorization (UE) and potential differences in the quality of uterine massage could explain the differences between the observed levels of uterine tone between the groups. The authors accept that the uterine massage technique was not standardized in this study and that the combination of uterine massage and prophylactic oxytocin are important in the management of uterine tone. They go on to suggest in their discussion that the routine use of 5 units of oxytocin during elective Caesarean delivery (CS) can no longer be recommended, as adequate uterine tone can occur with lower bolus doses of oxytocin. However, they fail to clarify in their final recommendation that this tone is due to the combination of exteriorization and uterine massage combined with the lower oxytocin doses. There is a significant difference in the rates of hypotension between the 0 and 5 units of oxytocin groups, however presumably no significant difference between the other groups (although the P-values are not given). This in combination with no significant reduction in other endpoints such as nausea and vomiting combined with the increased rates of rescue doses of oxytocin required in the lower dosing groups mean that a reduction in dose of oxytocin seems without strong evidence. In addition, UE has been linked with both increased nausea and vomiting2 and visceral pain on day 1 and 2 postdelivery,3 and these symptoms should be considered if considering routine UE and massage. Furthermore, if this combination of exteriorization, uterine massage and a reduced oxytocin dose is to be recommended, it should be with the proviso of anaesthesia by spinal anaesthesia (the method specified in this trial) rather than epidural anaesthesia (as performed for some elective deliveries). The depth of block during epidural anaesthesia is in my experience not usually adequate to allow for exteriorization and massage with the guarantee of lack of maternal visceral symptoms. E. Breeze * London, UK *E-mail: [email protected]
Editor—We wish to thank Dr Breeze for his interest in our study,1 and we appreciate the opportunity to respond to his comments. The prevalence of hypotension in study groups was displayed in Figure 3, and we confirm that statistically significant differences between groups were found only between groups receiving 0 vs 5 units of oxytocin. We acknowledge that our study was not powered to investigate
783
Downloaded from http://bja.oxfordjournals.org/ at Kokusai Hoken Keikakugaku (UNIV OF TOKYO) on June 13, 2015
Editor—We thank both sets of authors for their comments and interest in our letter and agree with their comments. As we made clear in our original correspondence, the i-look machine, marketed for use with superficial vascular procedures, may not produce images of sufficient quality to be used in this setting. Again, our original correspondence agrees with their comments that US-guided blocks of any type should only be performed by those who are adequately trained. It is our understanding that the operator opted for a level of insertion higher than the lumbar triangle of Petit due to the coincidental umbilical hernia repair in addition to the inguinal hernia repair and the necessary dermatomal coverage that this higher incision would require. A failure to adequately visualize the entire needle tip during this higher, subcostal needle placement was likely the cause of the liver trauma in this case. We have no experience in the use of TAP blocks in the day case setting and would exercise similar caution to that described by Drs Bhatia and Corcoran.
doi:10.1093/bja/aeq102
Transversus abdominis plane blocks and liver injury Editor—We are surprised to learn that a liver injury can occur from a transversus abdominis plane (TAP) block for hernia surgery with the use of ultrasound (US).1 We notice that the authors have used Sonosite i-look US, which in our opinion is inappropriate for performing such blocks. The resolution of this machine is very poor and the screen is so small that as the depth is increased, the window becomes increasingly smaller making it difficult to properly identify the anatomical structures and the needle. We agree that more and more people are doing TAP blocks but these blocks should only be done under supervision and by people who have training in using US for nerve blocks. For liver injury to occur from a TAP block for inguinal hernia repair, there can be only two reasons: (i) the operator was unable to identify the anatomy appropriately and was in a wrong place (too high); and (ii) the operator was unable to identify the tip of the needle (which is impossible with i-look). We do, and teach our trainees to do, TAP blocks and with the numbers we have done, have yet to see a major complication like this. We appreciate the authors’ contribution in highlighting this complication but would recommend that these blocks
should only be performed after adequate training and with the use of appropriate equipment.2 S. K. Singh * J. F. Corbett Liverpool, UK *E-mail: [email protected]
Editor—We read with great interest the case report of US-guided TAP block causing liver trauma1 in a patient undergoing an inguinal hernia repair. It is evident that this block which is considered simple and effective can have significant morbidity as was seen in this case. We wish to raise several points about TAP blocks and the use of US for this procedure. (1) The patient had a bilateral TAP block for the repair of strangulated inguinal hernia and umbilical hernia. Perhaps, it would have been useful to know whether the block was done using an in-plane approach or out-of-plane approach. We advocate an in-plane approach when performing US-guided TAP blocks as we believe that this allows easier visualization of the muscle layers and needle tip position. (2) We believe the key issue with this case was that the machine used to guide the procedure was designed for visualization of vascular structures, not for imaging of the abdominal wall, and as this case illustrates, the images produced are not adequate for use in the placement of US-guided TAP blocks. Visualization of the muscle layers of the abdominal wall can be difficult, and in our institution, TAP blocks are placed using higher resolution machines and the i-look machines are only used to guide vascular access. (3) The introduction of a new procedure requires appropriate training and the complication reported appears to be related more to the ability to identify the location of the needle tip rather than the block. (4) In a recent editorial3 on TAP blocks in this journal, it was highlighted that most of the studies published so far have been on a small number of patients and they are insufficient for the evaluation of safety and efficacy of TAP blocks. In addition to this case report, there have been other case reports4 highlighting the problems of TAP block including femoral nerve paresis.5 Hence, the TAP block should be used with caution in day-case procedures if no facilities exist for overnight admission and the patients are informed of these risks.
K. Bhatia * J. Corcoran Salford, UK *E-mail: [email protected]
782
Downloaded from http://bja.oxfordjournals.org/ at Kokusai Hoken Keikakugaku (UNIV OF TOKYO) on June 13, 2015
in infants following surgery for congenital heart disease. Pediatr Crit Care Med 2008; 9: 123– 4 8 Petrova A, Mehta R. Near-infrared spectroscopy in the detection of regional tissue oxygenation during hypoxic events in preterm infants undergoing critical care. Pediatr Crit Care Med 2006; 7: 449 – 54 9 Chertow GM, Levy EM, Hammermeister KE, Grover F, Daley J. Independent association between acute renal failure and mortality following cardiac surgery. Am J Med 1998; 104: 343 – 8 10 Mangano CM, Diamondstone LS, Ramsay JG, Aggarwal A, Herskowitz A, Mangano DT. Renal dysfunction after myocardial revascularization: risk factors, adverse outcomes, and hospital resource utilization. The Multicenter Study of Perioperative Ischemia Research Group. Ann Intern Med 1998; 128: 194– 203 11 Murkin JM, Adams SJ, Novick RJ, et al. Monitoring brain oxygen saturation during coronary bypass surgery: a randomized, prospective study. Anesth Analg 2007; 104: 51 – 8 12 Doerschug KC, Delsing AS, Schmidt GA, Haynes WG. Impairments in microvascular reactivity are related to organ failure in human sepsis. Am J Physiol Heart Circ Physiol 2007; 293: H1065–71 13 Donati A, Romanelli M, Botticelli L, et al. Recombinant activated protein C treatment improves tissue perfusion and oxygenation in septic patients measured by near-infrared spectroscopy. Crit Care 2009; 13(Suppl. 5): S12 14 Smith J, Bricker S, Putnam B. Tissue oxygen saturation predicts the need for early blood transfusion in trauma patients. Am Surg 2008; 74: 1006 – 11
Correspondence
Conflict of interest None declared. P. S. Lancaster * M. Chadwick Manchester, UK *E-mail: [email protected]
1 Lancaster P, Chadwick M. Liver trauma secondary to ultrasoundguided transversus abdominis plane block. Br J Anaesth 2010; 104: 509 – 10 2 Hargett MJ, Beckman JD, Liguori GA, et al. Guidelines for fellowship training in regional anesthesia Reg Anesth Pain Med 2005; 30: 218 3 Bonnet F, Berger J, Aveline C. Transversus abdominis plane block: what is its role in postoperative analgesia? Br J Anaesth 2009; 103: 468 – 70 4 Farooq M, Carey M. A case of liver trauma with a blunt regional anesthesia needle while performing transversus abdominis plane block. Reg Anesth Pain Med 2008; 33: 274 5 Walker G. Transversus abdominis plane block: a note of caution! Br J Anaesth 2010; 104: 265 doi:10.1093/bja/aeq103
Minimum effective bolus dose of oxytocin during elective Caesarean delivery Editor—I read with great interest the article by Butwick and colleagues1 regarding the determination of the lowest effective bolus dose of oxytocin to achieve adequate uterine tone during elective Caesarean section. The authors state that exteriorization of the uterus was performed at the discretion
of the obstetrician and that subsequent uterine massage was performed. It is not clear however whether exteriorization was routinely performed or whether the uterine massage occurred on some occasions with the uterus having not been exteriorized. If exteriorization rates varied between the groups involved then this could potentially be a confounding factor affecting oxytocin delivery to the uterus and the obstetricians’ ability to both perform uterine massage and assess uterine tone adequately. Varying rates of uterine exteriorization (UE) and potential differences in the quality of uterine massage could explain the differences between the observed levels of uterine tone between the groups. The authors accept that the uterine massage technique was not standardized in this study and that the combination of uterine massage and prophylactic oxytocin are important in the management of uterine tone. They go on to suggest in their discussion that the routine use of 5 units of oxytocin during elective Caesarean delivery (CS) can no longer be recommended, as adequate uterine tone can occur with lower bolus doses of oxytocin. However, they fail to clarify in their final recommendation that this tone is due to the combination of exteriorization and uterine massage combined with the lower oxytocin doses. There is a significant difference in the rates of hypotension between the 0 and 5 units of oxytocin groups, however presumably no significant difference between the other groups (although the P-values are not given). This in combination with no significant reduction in other endpoints such as nausea and vomiting combined with the increased rates of rescue doses of oxytocin required in the lower dosing groups mean that a reduction in dose of oxytocin seems without strong evidence. In addition, UE has been linked with both increased nausea and vomiting2 and visceral pain on day 1 and 2 postdelivery,3 and these symptoms should be considered if considering routine UE and massage. Furthermore, if this combination of exteriorization, uterine massage and a reduced oxytocin dose is to be recommended, it should be with the proviso of anaesthesia by spinal anaesthesia (the method specified in this trial) rather than epidural anaesthesia (as performed for some elective deliveries). The depth of block during epidural anaesthesia is in my experience not usually adequate to allow for exteriorization and massage with the guarantee of lack of maternal visceral symptoms. E. Breeze * London, UK *E-mail: [email protected]
Editor—We wish to thank Dr Breeze for his interest in our study,1 and we appreciate the opportunity to respond to his comments. The prevalence of hypotension in study groups was displayed in Figure 3, and we confirm that statistically significant differences between groups were found only between groups receiving 0 vs 5 units of oxytocin. We acknowledge that our study was not powered to investigate
783
Downloaded from http://bja.oxfordjournals.org/ at Kokusai Hoken Keikakugaku (UNIV OF TOKYO) on June 13, 2015
Editor—We thank both sets of authors for their comments and interest in our letter and agree with their comments. As we made clear in our original correspondence, the i-look machine, marketed for use with superficial vascular procedures, may not produce images of sufficient quality to be used in this setting. Again, our original correspondence agrees with their comments that US-guided blocks of any type should only be performed by those who are adequately trained. It is our understanding that the operator opted for a level of insertion higher than the lumbar triangle of Petit due to the coincidental umbilical hernia repair in addition to the inguinal hernia repair and the necessary dermatomal coverage that this higher incision would require. A failure to adequately visualize the entire needle tip during this higher, subcostal needle placement was likely the cause of the liver trauma in this case. We have no experience in the use of TAP blocks in the day case setting and would exercise similar caution to that described by Drs Bhatia and Corcoran.