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Pro: Regional anesthesia is an important component of the anesthetic technique for pediatric patients undergoing cardiac surgical procedures
PRO AND CON Paul G. Barash, MD Section Editor
Pro: Regional Anesthesia Is an Important Component of the Anesthetic Technique for Pediatric Patients Undergoing Cardiac Surgical Procedures David A. Rosen, MD, Kathleen R. Rosen, MD, and Gregory B. Hammer, MD
T
HE DEBATE ABOUT regional adjuvants in pediatric cardiothoracic surgery is stimulated by the perceived risks of these techniques in patients who will be anticoagulated. The central issue is the potential for increased morbidity and mortality beyond the risk of the surgical procedure as a result of an accumulation of blood in the central nervous system. Concerns are augmented by inherent attitudes and fears about cardiac surgery. HISTORICAL PERSPECTIVE
Recent history provides perspective on the need for the development of regional techniques in pediatric cardiothoracic surgery. In 1980, the use of neuromuscular blockers for anesthesia in critically ill pediatric patients was common. A popular belief was that “pediatric patients do not have pain.” The use of muscle relaxants to gain cooperation of patients in the pediatric intensive care unit was also frequent. A prominent pediatric cardiac surgeon at the time was noted for withholding opioids from his patients in the postoperative period. Pediatric anesthesia and pediatric intensive care unit specialists began to recognize that pediatric pain was a problem that needed to be addressed. The use of epidural opioids for children undergoing cardiac surgery began in the 1980s when the Rosens1 investigated the technique for its potential postoperative benefits. The hope was that a single caudal epidural dose given at the end of the procedure would be the only analgesic that would be needed to maintain comfort during the child’s postoperative course. Rosen and Rosen’s1 article described caudal injection of preservative-free morphine at the end of the procedure after reversal of the heparin and normalization of anticoagulation. The caudal approach was used because it was the most common
From the Department of Anesthesiology, West Virginia University, Morgantown, WV; and Dept. of Anesthesia, Stanford University Medical Center, Stanford, CA. Address reprint requests to David A. Rosen, MD, Department of Anesthesiology, Dept. of Pediatrics, West Virginia University, 3618 Health Sciences Center, Morgantown, WV 26506. Copyright 2002, Elsevier Science (USA). All rights reserved. 1053-0770/02/1603-0022$35.00/0 doi:10.1053/jcan.2002.124152 Key Words: cardiothoracic, cardiopulmonary bypass, regional techniques, anticoagulation, complications, bleeding
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pediatric approach to the peridural space, and small epidural catheters or needles were not readily available at the time. The initial study showed that giving opioids in the caudal epidural space could provide analgesia for thoracic pain. The quality of analgesia was excellent, but the duration was only 8 to 24 hours. The concept of preemptive analgesia was subsequently introduced. Epidural administration of analgesic medication before surgery and anticoagulation with heparin offered the potential benefits of preemptive analgesia, providing intraoperative analgesia and sympathetic blockade that prevented activation of central nervous system pathways. Continuous infusion or additional boluses further extended the comfort postoperatively. COMPLICATIONS
Potential bleeding is the primary argument against regional techniques for cardiac surgery (Table 1). In patients receiving long-term anticoagulation therapy, the literature confirms a correlation between spinal regional techniques and neurologic injury.2 If patients were not taking anticoagulant drugs preoperatively, no significant hematomas were reported in cardiac surgery patients. Case reports of complications are sparse. Individual authors are unlikely to report problems, but in reality the incidence is probably low. Ho et al3 estimated the range for a clinically significant hematoma at 1:150,000 to 1:1,500. In a large pediatric noncardiac epidural study with ⬎24,000 children, only 5 serious events were noted that possibly could be related to the placement of an epidural catheter.4 In all 5 cases, the epidural space was identified with air. It was concluded that injection of air into the epidural space caused these problems. It has long been recognized that air injected into the epidural space can be seen on echocardiography in the intravascular system. It was not concluded that doing epidurals should be stopped, but the use of saline was recommended for identification of the epidural space. In pediatric cardiac surgical patients, 2 studies of regional techniques reiterate how uncommon the problems are. Hammer et al5 reported no incidence of bleeding in 50 patients. Peterson et al6 studied 220 patients and noted 1 incident of bleeding without complication. At West Virginia University Children’s Hospital, data were prospectively collected on all children undergoing cardiothoracic procedures with regional techniques
Journal of Cardiothoracic and Vascular Anesthesia, Vol 16, No 3 (June), 2002: pp 374-378
PRO AND CON
375
Table 1. Arguments Against Regional Anesthesia Techniques Authors/Year
Conclusions
Turnbull 1996 Chaney et al 1996 Christopherson and Norris 1997 Aouad and Baraka 1999
True incidence of neuraxial blockade hematoma undetermined Postoperative stress response not reliably attenuated intraoperatively and postoperatively No substantial benefit of neuraxial blockade Central neuraxial blockade should be avoided in anticoagulated patients Potential risks of neuraxial blockade far outweigh potential benefits (which can be obtained by other modalities) Inconclusive evidence of benefits compared with serious risks of bleeding Studies not conducted on pediatric patients Advantages exist, but so does risk of hematoma Data on benefits of neuraxial blockade unconvincing, and procedure should not be used on vascular patients
Nikolov 2000 Steven and McGowan 2000 Drolet and Girard 2001 Samama and Baillard 2001
Turnbull KW: Con: Neuraxial block is useful in patients undergoing heparinization for surgery. J Cardiothorac Vasc Anesth 10:961, 1996 Chaney MA, Smith KR, Barclay JC, Slogoff S: Large-dose intrathecal morphine for coronary artery bypass grafts. Anesth Analg 83:215, 1996 Christopherson R, Norris EJ: Regional versus general anesthesia. Anesthesiol Clin North Am 15:38, 1997 Aouad MT, Baraka AS: Haemostasis-altering drugs and central neuraxial block. Middle East J Anesthesiol 15:217, 1999 Nikolov MP: Thoracic epidurals are worth the risk of hematoma formation in patients undergoing full or partial systemic heparinization. CON. Society of Cardiovascular Anesthesiologists Newsletters 2000 June. Available at http://www.scahq.org/sca3/newsletters/june2000_con.shtml Steven JM, McGowan FX: Neuraxial blockade for pediatric cardiac surgery: Lessons yet to be learned. Anesth Analg 90:1011, 2000 Drolet P, Girard M: [Locoregional neuraxial anesthesia and vascular surgery: The benefits]. Can Anesthes 48:65, 2001 Samama CM, Baillard C: [Locoregional neuraxial anesthesia as used in vascular surgery]. Can Anesthes 48:72, 2001
(n ⫽ 1109), and bleeding was found to occur in 8% of placements.7 The incidence of bleeding when the epidural is placed at the thoracic level is lower than at the caudal insertion site. The patients who did have bleeding have been followed for 6 years with no neurologic deficits that could be attributed to placement of the epidural catheter. Bleeding as a result of caudally placed catheters left at the sacral or lower lumbar level is of little consequence because there are few vital structures that can be compromised. In the pediatric patient, the sacrococcygeal ligament is noncalcified, and blood that otherwise would accumulate there either would leak through the ligament or would be apparent. The authors recommend that the regional procedure be performed at least 1 hour before anticoagulation with heparin for the caudal space and at least 3 hours in the thoracic epidural space to minimize the risk in the event that bleeding does occur. Hammer et al5 and Peterson et al6 used shorter intervals between placement and anticoagulation with heparin for thoracic catheters. These time intervals are shorter than the time being practiced in many adult centers. In adults, the catheters are placed 24 hours before surgery to minimize risk. In small children, performing regional procedures awake increases the occurrence of bleeding or cerebrospinal fluid leak during the procedure. Administering another anesthetic for catheter placement alone is also an unacceptable risk. Maximizing the time between placement and anticoagulation and confirming normal coagulation before removal are prudent. Success with any technique may be limited by structural defects. Rowney and Doyle8 reviewed epidural blockade in children and emphasized the fact that the posterior epidural space is divided into right and left dorsolateral compartments. There also are anterior and posterior compartments in the epidural space. These divisions are more common in the caudal space and less common in the thoracic space. The multiple
tissue layers may explain the increased bleeding from caudally placed catheters compared with thoracic catheters. Peterson et al6 reported that the regional site with the lowest incidence of complications was the thoracic epidural approach. This may be the optimal epidural approach because it provides the most selective anesthesia and analgesia. The shorter catheter length decreases the potential for venous complications. The thoracic approach also allows rapid identification of problems because lower extremity motor blockade is less common. Any lower extremity motor weakness must be followed closely from it first recognition. Peterson et al6 also observed a lower incidence of paresthesia with the thoracic approach compared with the lumbar approach. One possible explanation for this finding is that only clinicians skilled at regional anesthesia would even attempt thoracic epidural placement in adults, much less in pediatric patients. The ultimate conclusion should be that for the practitioner experienced at performing epidural anesthesia, the thoracic epidural approach may be optimal. If the practitioner is less adept, the caudal approach may be preferred. If the clinician is hesitant, selecting a different technique is preferable. The pro-and-con debate is similar to other comparisons of anesthetic technique, which conclude that the anesthesiologists should select the technique that they perform best. The other issues are less important. Besides blood, clear fluid may be aspirated during epidural placement. In the authors’ West Virginia series (n ⫽ 1109), a clear fluid, which may have been cerebrospinal fluid, was aspirated in only 1% of the cases.7 All of these clear aspirations were observed with caudally placed catheters and recognized before drug injection. The epidural dose of opioids would produce significant respiratory depression if given intrathecally. No respiratory depression was seen in these patients. Hammer et al5 reported using subarachnoid techniques intentionally for cardiothoracic procedures. They confirmed the ef-
376
ROSEN ET AL
Table 2. Arguments for Regional Anesthetic Techniques Authors/year
Rasch et al/1990
Liem, et al 1992 Stenseth, et al 1994 Fawcett, et al 1997
Sanchez and Nygard 1998
Moon, et al 1999 Hammer 199913
Bichel et al 2000 Gramling-Babb 2000 Grass 2000
Nader, et al 200019
Rodgers, et al 200014
Hammer, et al 20005
Conclusions
More rapid recovery of appetite and ambulation Decreased circulating stress hormone levels and expedited weaning from the ventilator in neonates Children ⬍2 years old should be monitored in an intensive care unit because of the risk of apnea Better postoperative pain relief Decreased epinephrine and cortisol plasma concentrations More effective blockade of stress response Significantly lower pain scores Less impaired postoperative respiratory function Catecholamine concentrations effectively inhibited No increased risk of spinal hematoma No increased risk of short-term neurologic complications Improved myocardial blood flow and oxygen supply Improved postoperative pulmonary function and recovery Superior to patient controlled analgesia in providing analgesia, improving pulmonary function, and modifying the immune response May attenuate stress response May decrease morbidity and mortality May provide improved pulmonary function, greater circulatory stability, and postoperative pain control Significantly decreased circulating catecholamines intraoperatively and postoperatively Benefits far outweigh risks of hematoma Decreased stress response, pain, heart rate, mean arterial pressure, and systemic vascular resistance Reduced postoperative morbidity Expedited recovery Decreased incidence of cardiac and pulmonary complications Suppression of neuroendocrine stress response Earlier return of gastrointestinal function Better postoperative pain management Lower incidence of respiratory depression No increased incidence of hematoma Reduces risk of postoperative mortality, deep vein thrombosis, pulmonary embolism, myocardial infarctions, wound infections and bleeding complications, pneumonia, respiratory depression, and renal failure Required significantly less sedative/analgesic interventions
Rasch DK, Webster DE, Pollard TG, et al: Lumbar and thoracic epidural analgesia via the caudal approach for postoperative pain relief in infants and children. Can J Anaesth 37:359, 1990 Liem TH, Booij LH, Gielen MJ, et al: Coronary artery bypass grafting using two different anesthetic techniques: Part 3. Adrenergic responses. J Cardiothorac Vasc Surg 6:162, 1992 Stenseth R, Bjella L, Berg EM, et al: Thoracic epidural analgesia in aortocoronary bypass surgery: II. Effects on the endocrine metabolic response. Acta Anaesthesiol Scand 38:834, 1994 Fawcett WJ, Edwards RE, Quinn AC, et al: Thoracic epidural analgesia started after cardiopulmonary bypass: Adrenergic, cardiovascular and respiratory sequelae. Anaesthesia 52:294, 1997 Sanchez R, Nygard E: Epidural anesthesia in cardiac surgery: Is there an increased risk? J Cardiothorac Vasc Anesth 12:170, 1998 Moon MR, Luchette FA, Gibson SW, et al: Prospective, randomized comparison of epidural versus parenteral opioid analgesia in thoracic trauma. Ann Surg 229:684, 1999 Bichel T, Rouge JC, Schegel S, et al: Epidural sufentanil during paediatric cardiac surgery: Effects on metabolic response and post operative outcome. Paediatr Anaesth 10:609, 2000 Gramling-Babb P: Thoracic epidurals are worth the risk of hematoma formation in patients undergoing full or partial systemic heparinization. PRO. Society of Cardiovascular Anesthesiologists Newsletters, June 2000 Grass J: The role of epidural anesthesia and analgesia in postoperative outcome. Anesthesiol Clin North Am 18:407, 2000
ficacy of subarachnoid blockade intraoperatively but recognized that the duration is less than epidural techniques in the postoperative period. POTENTIAL BENEFITS
Steven and McGowan9 asserted that it is difficult to establish the superiority of a regional technique compared with a good intravenous anesthesia and analgesia technique. The
benefits of regional techniques would likely be subtle. Studies found free radical scavenging and thyroid hormone levels to be preserved better with regional techniques compared with intravenous opioid anesthesia.10,11 In another study comparing regional with intravenous techniques, when the anesthesiologist and perfusionist were blinded to technique, they were able to predict whether epidural opiate had been administered.12
PRO AND CON
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Two large reviews of regional anesthesia in pediatric cardiac surgery by Hammer et al5,13 focused on the decreased stress response, improved pulmonary and gastrointestinal function, and resultant potential for cost reduction when regional techniques are used (Table 2). The subsequent large series by Rodgers et al14 reported further small but significant reductions in mortality and morbidity with the inclusion of regional techniques. Other authors have questioned whether these results can be generalized to other types of surgery. Jonathan and Wilson15 and Moore et al16 concluded that when neuroendocrine factors are the primary mediator of stress response, regional techniques have their greatest benefit. This advantage is found in cardiac surgical patients. CARDIOPULMONARY BYPASS
Cardiopulmonary bypass is an essential adjunct for many pediatric cardiac procedures, but there is a significant risk for neuropyschologic events.17 The skeptics project that these devastating injuries may be increased by injection of drugs in proximity to the cerebrospinal fluid. These fears should not justify avoidance of regional techniques, however. It is unrealistic to speculate that these agents could prevent neuropsychologic catastrophes, but free radical formation is implicated in many neuropsychologic events. Many of the drugs used in the epidural space are potent free radical scavengers. Epidural morphine can scavenge free radicals and theoretically may provide neurologic protection. Epidural injection was thought to be contraindicated in patients with coarctation of the aorta because of the significant potential for neurologic complications during repair of the coarctation.18 At West Virginia University, the authors have followed 60 patients after coarctation repair. There have been no neurologic deficits despite peridural bleeding in 3 of these patients, which supports the hypothetical neuroprotection of epidural narcotics.7 The authors have had 2 patients who underwent cardiopulmonary bypass with epidural catheters who developed intracranial cerebrovascular events. Both patients were extubated at the end of surgery, and their neurologic events became apparent. Anecdotally, both patients recovered faster and more com-
pletely than their computed tomography scans would have predicted. POSTOPERATIVE MANAGEMENT
The management of the cardiac surgical patients postoperatively is the initial and sustaining rationale for regional analgesia. Early extubation is facilitated by regional techniques. The detractors claim that early extubation is equally successful with general anesthesia, or they assert that early extubation is not beneficial. Nader et al19 described multiple respiratory advantages of regional techniques. Perioperative ventilatory depression was lower. They reported a 6-fold increase in early extubation and had lower partial pressures of carbon dioxide in patients in whom regional techniques were used. In the authors’ experience, all aspects of postoperative management are easier if the patient is comfortable. There is a remarkable difference for children without regional analgesia. Pediatric cardiac surgical patient comfort was studied at the University of Michigan and West Virginia University, where regional techniques were compared with intravenous techniques. Nurses documented that patients receiving regional techniques had better analgesia, allowing for easier care of these patients.20 In conclusion, there is ample evidence that regional techniques are effective and safe for pediatric patients undergoing cardiac surgery. It also is apparent that there will be advocates for both approaches because the comparison is not one of a good technique versus a bad one. Regional techniques are not for everyone. Some patients have contraindications, and some anesthesiologists are not facile with the techniques. No centers that began offering regional plus general anesthesia for cardiac surgery in children have stopped because of patient complications. Regional techniques facilitate intraoperative and postoperative management. Further studies need to focus on maximizing comfort for the pediatric patient rather than trying to vilify or glorify a specific technique. ACKNOWLEDGMENT The authors thank research assistants, Elizabeth Nelson and Lori Kenamond, for their efforts in preparation of this manuscript.
REFERENCES 1. Rosen KR, Rosen DA: Caudal morphine for control of postoperative pain in children. Anesthesiology 70:418-421, 1989 2. Lumpkin MM: Reports of epidural or spinal hematomas with the concurrent use of low molecular weight heparin and spinal/epidural anesthesia or spinal puncture. FDA public health advisory. U.S. Department of Health and Human Services Public Health Service, December 15, 1997 3. Ho AM, Chung DC, Joynt GM: Neuraxial blockade and hematoma in cardiac surgery: Estimating the risk of a rare adverse event that has not (yet) occurred. Chest 117:551-555, 2000 4. Flandin-Blety C, Barrier G: Accidents following extradural analgesia in children: The results of a retrospective study. Paediatr Anesth 5:41-46, 1995 5. Hammer GB, Ngo K, Maracio A: A retrospective examination of regional plus general anesthesia in children undergoing open-heart surgery. Anesth Analg 90:1020-1024, 2000
6. Peterson KL, DeCampli WM, Pike NA, et al: A report of two hundred twenty cases of regional anesthesia in pediatric cardiac surgery. Anesth Analg 90:1014-1019, 2000 7. Rosen DA, Rosen KR, Gustafson RA, et al: Long-term follow-up in children undergoing cardiothoracic procedures with epidural anesthesia/analgesia. American Society of Anesthesiologist Annual Meeting A-1298, 2001 (abstract) 8. Rowney DA, Doyle E: Epidural and subarachnoid blockade in children. Anaesthesia 53:980-1001, 1998 9. Steven JM, McGowan Jr FX: Neuroaxial blockade for pediatric cardiac surgery: Lessons yet to be learned. Anesth Analg 90:10111013, 2000 10. Rosen DA, Rosen KR, Pyles LA, et al: Caudal morphine and plasma antioxidant in children undergoing cardiopulmonary bypass. Anesthesiology 79:1149, 1993
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11. Rosen DA, Matheny JM, Steelman RJ: Epidural narcotic technique: Effective in preserving T3 levels in children. Presented at Society for Pediatric Anesthesia, San Antonio, TX, March 1997 12. Rosen DA, Rosen KR, Matheny JM, et al: Maintenance of T3 levels in children undergoing cardiac Surgery. Anesthesiology 83: 1069, 1997 13. Hammer GB: Regional anesthesia for pediatric cardiac surgery. J Cardiothorac Vasc Anesth 13:210, 1999 14. Rodgers A, Walker N, Schug S: Reduction of postoperative mortality and morbidity with epidural or spinal anesthesia: Results from overview of randomized trials. BMJ 321:1493, 2000 15. Jonathan R, Wilson T: Outcome benefits from epidural anesthesia: True for all groups? BMJ.com, Dec 20, 2000. Available at http:// www.bmj.com/cgi/eletters/321/7275/1493#EL3
ROSEN ET AL
16. Moore CM, Desborough JP, Powell H, et al: Effects of extradural anaesthesia on interleukin-6 and acute phase response to surgery. Br J Anaesth 72:272, 1994 17. Mora CT, Henson MB, Weintraub WS, et al: The effect of temperature management during cardiopulmonary bypass on neurologic and neuropsychologic outcomes in patients undergoing coronary revascularization. J Thorac Cardiovasc Surg 112:514, 1996 18. Connolly JE: Prevention of spinal cord complications in aortic surgery. Am J Surg 176:92, 1998 19. Nader N, Peppriell J, Panos A, Bacon DR: Potential beneficial effects of intrathecal opioids in cardiac surgical patients. Internet Journal of Anesthesiology 4, 2000 Available at http://www.icaap.org/ iuicode?81.4.2.4 20. Callow LB, Rosen DA, Rosen KR, et al: Optimal pain relief following cardiac surgery in children. Circulation 86:I-501, 1992
Pro: Regional Anesthesia Is an Important Component of the Anesthetic Technique for Pediatric Patients Undergoing Cardiac Surgical Procedures David A. Rosen, MD, Kathleen R. Rosen, MD, and Gregory B. Hammer, MD
T
HE DEBATE ABOUT regional adjuvants in pediatric cardiothoracic surgery is stimulated by the perceived risks of these techniques in patients who will be anticoagulated. The central issue is the potential for increased morbidity and mortality beyond the risk of the surgical procedure as a result of an accumulation of blood in the central nervous system. Concerns are augmented by inherent attitudes and fears about cardiac surgery. HISTORICAL PERSPECTIVE
Recent history provides perspective on the need for the development of regional techniques in pediatric cardiothoracic surgery. In 1980, the use of neuromuscular blockers for anesthesia in critically ill pediatric patients was common. A popular belief was that “pediatric patients do not have pain.” The use of muscle relaxants to gain cooperation of patients in the pediatric intensive care unit was also frequent. A prominent pediatric cardiac surgeon at the time was noted for withholding opioids from his patients in the postoperative period. Pediatric anesthesia and pediatric intensive care unit specialists began to recognize that pediatric pain was a problem that needed to be addressed. The use of epidural opioids for children undergoing cardiac surgery began in the 1980s when the Rosens1 investigated the technique for its potential postoperative benefits. The hope was that a single caudal epidural dose given at the end of the procedure would be the only analgesic that would be needed to maintain comfort during the child’s postoperative course. Rosen and Rosen’s1 article described caudal injection of preservative-free morphine at the end of the procedure after reversal of the heparin and normalization of anticoagulation. The caudal approach was used because it was the most common
From the Department of Anesthesiology, West Virginia University, Morgantown, WV; and Dept. of Anesthesia, Stanford University Medical Center, Stanford, CA. Address reprint requests to David A. Rosen, MD, Department of Anesthesiology, Dept. of Pediatrics, West Virginia University, 3618 Health Sciences Center, Morgantown, WV 26506. Copyright 2002, Elsevier Science (USA). All rights reserved. 1053-0770/02/1603-0022$35.00/0 doi:10.1053/jcan.2002.124152 Key Words: cardiothoracic, cardiopulmonary bypass, regional techniques, anticoagulation, complications, bleeding
374
pediatric approach to the peridural space, and small epidural catheters or needles were not readily available at the time. The initial study showed that giving opioids in the caudal epidural space could provide analgesia for thoracic pain. The quality of analgesia was excellent, but the duration was only 8 to 24 hours. The concept of preemptive analgesia was subsequently introduced. Epidural administration of analgesic medication before surgery and anticoagulation with heparin offered the potential benefits of preemptive analgesia, providing intraoperative analgesia and sympathetic blockade that prevented activation of central nervous system pathways. Continuous infusion or additional boluses further extended the comfort postoperatively. COMPLICATIONS
Potential bleeding is the primary argument against regional techniques for cardiac surgery (Table 1). In patients receiving long-term anticoagulation therapy, the literature confirms a correlation between spinal regional techniques and neurologic injury.2 If patients were not taking anticoagulant drugs preoperatively, no significant hematomas were reported in cardiac surgery patients. Case reports of complications are sparse. Individual authors are unlikely to report problems, but in reality the incidence is probably low. Ho et al3 estimated the range for a clinically significant hematoma at 1:150,000 to 1:1,500. In a large pediatric noncardiac epidural study with ⬎24,000 children, only 5 serious events were noted that possibly could be related to the placement of an epidural catheter.4 In all 5 cases, the epidural space was identified with air. It was concluded that injection of air into the epidural space caused these problems. It has long been recognized that air injected into the epidural space can be seen on echocardiography in the intravascular system. It was not concluded that doing epidurals should be stopped, but the use of saline was recommended for identification of the epidural space. In pediatric cardiac surgical patients, 2 studies of regional techniques reiterate how uncommon the problems are. Hammer et al5 reported no incidence of bleeding in 50 patients. Peterson et al6 studied 220 patients and noted 1 incident of bleeding without complication. At West Virginia University Children’s Hospital, data were prospectively collected on all children undergoing cardiothoracic procedures with regional techniques
Journal of Cardiothoracic and Vascular Anesthesia, Vol 16, No 3 (June), 2002: pp 374-378
PRO AND CON
375
Table 1. Arguments Against Regional Anesthesia Techniques Authors/Year
Conclusions
Turnbull 1996 Chaney et al 1996 Christopherson and Norris 1997 Aouad and Baraka 1999
True incidence of neuraxial blockade hematoma undetermined Postoperative stress response not reliably attenuated intraoperatively and postoperatively No substantial benefit of neuraxial blockade Central neuraxial blockade should be avoided in anticoagulated patients Potential risks of neuraxial blockade far outweigh potential benefits (which can be obtained by other modalities) Inconclusive evidence of benefits compared with serious risks of bleeding Studies not conducted on pediatric patients Advantages exist, but so does risk of hematoma Data on benefits of neuraxial blockade unconvincing, and procedure should not be used on vascular patients
Nikolov 2000 Steven and McGowan 2000 Drolet and Girard 2001 Samama and Baillard 2001
Turnbull KW: Con: Neuraxial block is useful in patients undergoing heparinization for surgery. J Cardiothorac Vasc Anesth 10:961, 1996 Chaney MA, Smith KR, Barclay JC, Slogoff S: Large-dose intrathecal morphine for coronary artery bypass grafts. Anesth Analg 83:215, 1996 Christopherson R, Norris EJ: Regional versus general anesthesia. Anesthesiol Clin North Am 15:38, 1997 Aouad MT, Baraka AS: Haemostasis-altering drugs and central neuraxial block. Middle East J Anesthesiol 15:217, 1999 Nikolov MP: Thoracic epidurals are worth the risk of hematoma formation in patients undergoing full or partial systemic heparinization. CON. Society of Cardiovascular Anesthesiologists Newsletters 2000 June. Available at http://www.scahq.org/sca3/newsletters/june2000_con.shtml Steven JM, McGowan FX: Neuraxial blockade for pediatric cardiac surgery: Lessons yet to be learned. Anesth Analg 90:1011, 2000 Drolet P, Girard M: [Locoregional neuraxial anesthesia and vascular surgery: The benefits]. Can Anesthes 48:65, 2001 Samama CM, Baillard C: [Locoregional neuraxial anesthesia as used in vascular surgery]. Can Anesthes 48:72, 2001
(n ⫽ 1109), and bleeding was found to occur in 8% of placements.7 The incidence of bleeding when the epidural is placed at the thoracic level is lower than at the caudal insertion site. The patients who did have bleeding have been followed for 6 years with no neurologic deficits that could be attributed to placement of the epidural catheter. Bleeding as a result of caudally placed catheters left at the sacral or lower lumbar level is of little consequence because there are few vital structures that can be compromised. In the pediatric patient, the sacrococcygeal ligament is noncalcified, and blood that otherwise would accumulate there either would leak through the ligament or would be apparent. The authors recommend that the regional procedure be performed at least 1 hour before anticoagulation with heparin for the caudal space and at least 3 hours in the thoracic epidural space to minimize the risk in the event that bleeding does occur. Hammer et al5 and Peterson et al6 used shorter intervals between placement and anticoagulation with heparin for thoracic catheters. These time intervals are shorter than the time being practiced in many adult centers. In adults, the catheters are placed 24 hours before surgery to minimize risk. In small children, performing regional procedures awake increases the occurrence of bleeding or cerebrospinal fluid leak during the procedure. Administering another anesthetic for catheter placement alone is also an unacceptable risk. Maximizing the time between placement and anticoagulation and confirming normal coagulation before removal are prudent. Success with any technique may be limited by structural defects. Rowney and Doyle8 reviewed epidural blockade in children and emphasized the fact that the posterior epidural space is divided into right and left dorsolateral compartments. There also are anterior and posterior compartments in the epidural space. These divisions are more common in the caudal space and less common in the thoracic space. The multiple
tissue layers may explain the increased bleeding from caudally placed catheters compared with thoracic catheters. Peterson et al6 reported that the regional site with the lowest incidence of complications was the thoracic epidural approach. This may be the optimal epidural approach because it provides the most selective anesthesia and analgesia. The shorter catheter length decreases the potential for venous complications. The thoracic approach also allows rapid identification of problems because lower extremity motor blockade is less common. Any lower extremity motor weakness must be followed closely from it first recognition. Peterson et al6 also observed a lower incidence of paresthesia with the thoracic approach compared with the lumbar approach. One possible explanation for this finding is that only clinicians skilled at regional anesthesia would even attempt thoracic epidural placement in adults, much less in pediatric patients. The ultimate conclusion should be that for the practitioner experienced at performing epidural anesthesia, the thoracic epidural approach may be optimal. If the practitioner is less adept, the caudal approach may be preferred. If the clinician is hesitant, selecting a different technique is preferable. The pro-and-con debate is similar to other comparisons of anesthetic technique, which conclude that the anesthesiologists should select the technique that they perform best. The other issues are less important. Besides blood, clear fluid may be aspirated during epidural placement. In the authors’ West Virginia series (n ⫽ 1109), a clear fluid, which may have been cerebrospinal fluid, was aspirated in only 1% of the cases.7 All of these clear aspirations were observed with caudally placed catheters and recognized before drug injection. The epidural dose of opioids would produce significant respiratory depression if given intrathecally. No respiratory depression was seen in these patients. Hammer et al5 reported using subarachnoid techniques intentionally for cardiothoracic procedures. They confirmed the ef-
376
ROSEN ET AL
Table 2. Arguments for Regional Anesthetic Techniques Authors/year
Rasch et al/1990
Liem, et al 1992 Stenseth, et al 1994 Fawcett, et al 1997
Sanchez and Nygard 1998
Moon, et al 1999 Hammer 199913
Bichel et al 2000 Gramling-Babb 2000 Grass 2000
Nader, et al 200019
Rodgers, et al 200014
Hammer, et al 20005
Conclusions
More rapid recovery of appetite and ambulation Decreased circulating stress hormone levels and expedited weaning from the ventilator in neonates Children ⬍2 years old should be monitored in an intensive care unit because of the risk of apnea Better postoperative pain relief Decreased epinephrine and cortisol plasma concentrations More effective blockade of stress response Significantly lower pain scores Less impaired postoperative respiratory function Catecholamine concentrations effectively inhibited No increased risk of spinal hematoma No increased risk of short-term neurologic complications Improved myocardial blood flow and oxygen supply Improved postoperative pulmonary function and recovery Superior to patient controlled analgesia in providing analgesia, improving pulmonary function, and modifying the immune response May attenuate stress response May decrease morbidity and mortality May provide improved pulmonary function, greater circulatory stability, and postoperative pain control Significantly decreased circulating catecholamines intraoperatively and postoperatively Benefits far outweigh risks of hematoma Decreased stress response, pain, heart rate, mean arterial pressure, and systemic vascular resistance Reduced postoperative morbidity Expedited recovery Decreased incidence of cardiac and pulmonary complications Suppression of neuroendocrine stress response Earlier return of gastrointestinal function Better postoperative pain management Lower incidence of respiratory depression No increased incidence of hematoma Reduces risk of postoperative mortality, deep vein thrombosis, pulmonary embolism, myocardial infarctions, wound infections and bleeding complications, pneumonia, respiratory depression, and renal failure Required significantly less sedative/analgesic interventions
Rasch DK, Webster DE, Pollard TG, et al: Lumbar and thoracic epidural analgesia via the caudal approach for postoperative pain relief in infants and children. Can J Anaesth 37:359, 1990 Liem TH, Booij LH, Gielen MJ, et al: Coronary artery bypass grafting using two different anesthetic techniques: Part 3. Adrenergic responses. J Cardiothorac Vasc Surg 6:162, 1992 Stenseth R, Bjella L, Berg EM, et al: Thoracic epidural analgesia in aortocoronary bypass surgery: II. Effects on the endocrine metabolic response. Acta Anaesthesiol Scand 38:834, 1994 Fawcett WJ, Edwards RE, Quinn AC, et al: Thoracic epidural analgesia started after cardiopulmonary bypass: Adrenergic, cardiovascular and respiratory sequelae. Anaesthesia 52:294, 1997 Sanchez R, Nygard E: Epidural anesthesia in cardiac surgery: Is there an increased risk? J Cardiothorac Vasc Anesth 12:170, 1998 Moon MR, Luchette FA, Gibson SW, et al: Prospective, randomized comparison of epidural versus parenteral opioid analgesia in thoracic trauma. Ann Surg 229:684, 1999 Bichel T, Rouge JC, Schegel S, et al: Epidural sufentanil during paediatric cardiac surgery: Effects on metabolic response and post operative outcome. Paediatr Anaesth 10:609, 2000 Gramling-Babb P: Thoracic epidurals are worth the risk of hematoma formation in patients undergoing full or partial systemic heparinization. PRO. Society of Cardiovascular Anesthesiologists Newsletters, June 2000 Grass J: The role of epidural anesthesia and analgesia in postoperative outcome. Anesthesiol Clin North Am 18:407, 2000
ficacy of subarachnoid blockade intraoperatively but recognized that the duration is less than epidural techniques in the postoperative period. POTENTIAL BENEFITS
Steven and McGowan9 asserted that it is difficult to establish the superiority of a regional technique compared with a good intravenous anesthesia and analgesia technique. The
benefits of regional techniques would likely be subtle. Studies found free radical scavenging and thyroid hormone levels to be preserved better with regional techniques compared with intravenous opioid anesthesia.10,11 In another study comparing regional with intravenous techniques, when the anesthesiologist and perfusionist were blinded to technique, they were able to predict whether epidural opiate had been administered.12
PRO AND CON
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Two large reviews of regional anesthesia in pediatric cardiac surgery by Hammer et al5,13 focused on the decreased stress response, improved pulmonary and gastrointestinal function, and resultant potential for cost reduction when regional techniques are used (Table 2). The subsequent large series by Rodgers et al14 reported further small but significant reductions in mortality and morbidity with the inclusion of regional techniques. Other authors have questioned whether these results can be generalized to other types of surgery. Jonathan and Wilson15 and Moore et al16 concluded that when neuroendocrine factors are the primary mediator of stress response, regional techniques have their greatest benefit. This advantage is found in cardiac surgical patients. CARDIOPULMONARY BYPASS
Cardiopulmonary bypass is an essential adjunct for many pediatric cardiac procedures, but there is a significant risk for neuropyschologic events.17 The skeptics project that these devastating injuries may be increased by injection of drugs in proximity to the cerebrospinal fluid. These fears should not justify avoidance of regional techniques, however. It is unrealistic to speculate that these agents could prevent neuropsychologic catastrophes, but free radical formation is implicated in many neuropsychologic events. Many of the drugs used in the epidural space are potent free radical scavengers. Epidural morphine can scavenge free radicals and theoretically may provide neurologic protection. Epidural injection was thought to be contraindicated in patients with coarctation of the aorta because of the significant potential for neurologic complications during repair of the coarctation.18 At West Virginia University, the authors have followed 60 patients after coarctation repair. There have been no neurologic deficits despite peridural bleeding in 3 of these patients, which supports the hypothetical neuroprotection of epidural narcotics.7 The authors have had 2 patients who underwent cardiopulmonary bypass with epidural catheters who developed intracranial cerebrovascular events. Both patients were extubated at the end of surgery, and their neurologic events became apparent. Anecdotally, both patients recovered faster and more com-
pletely than their computed tomography scans would have predicted. POSTOPERATIVE MANAGEMENT
The management of the cardiac surgical patients postoperatively is the initial and sustaining rationale for regional analgesia. Early extubation is facilitated by regional techniques. The detractors claim that early extubation is equally successful with general anesthesia, or they assert that early extubation is not beneficial. Nader et al19 described multiple respiratory advantages of regional techniques. Perioperative ventilatory depression was lower. They reported a 6-fold increase in early extubation and had lower partial pressures of carbon dioxide in patients in whom regional techniques were used. In the authors’ experience, all aspects of postoperative management are easier if the patient is comfortable. There is a remarkable difference for children without regional analgesia. Pediatric cardiac surgical patient comfort was studied at the University of Michigan and West Virginia University, where regional techniques were compared with intravenous techniques. Nurses documented that patients receiving regional techniques had better analgesia, allowing for easier care of these patients.20 In conclusion, there is ample evidence that regional techniques are effective and safe for pediatric patients undergoing cardiac surgery. It also is apparent that there will be advocates for both approaches because the comparison is not one of a good technique versus a bad one. Regional techniques are not for everyone. Some patients have contraindications, and some anesthesiologists are not facile with the techniques. No centers that began offering regional plus general anesthesia for cardiac surgery in children have stopped because of patient complications. Regional techniques facilitate intraoperative and postoperative management. Further studies need to focus on maximizing comfort for the pediatric patient rather than trying to vilify or glorify a specific technique. ACKNOWLEDGMENT The authors thank research assistants, Elizabeth Nelson and Lori Kenamond, for their efforts in preparation of this manuscript.
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