Tarek M Sarhan, Assistant professor of Anesthesiology, Faculty of Medicine, Alexandria University

Transcription

1 7 ANALGESIA FOR TRACHEOESOPHAGEAL FISTULA REPAIR IN NEONATES : A COMPARISON OF SINGLE SHOT THORACIC PARAVERTEBRAL BLOCK AND EPIDURAL BLOCK WITH ROPIVACAINE Tarek M Sarhan, Assistant professor of Anesthesiology, Faculty of Medicine, Alexandria University Abstract Introduction and aim of the work: perioperative pain treatment in neonates is often insufficient.we aimed to compare a single shot thoracic paravertebral and epidural block with ropivacine for analgesia of tracheoesophageal fistula repair in neonates. Patients and methods: this study was carried out on 24 neonates, they were randomly allocated into two groups after general anesthesia, Group I had a single shot unilateral thoracic paravertebral block with ml/kg body weight of ropivacaine.375% and Group II had thoracic epidural block with ml/kg body weight of.375% ropivacaine. Measurements : mean heart rate and blood pressure, Mean concentration of Sevoflurane, neonatal infant pain Score (NIPS) were measured in both groups. Results: There was no statistically significant difference in the mean sevoflurane concentration in both groups (2.±.34%) in group I versus.9±.8 %) in group II, There was statistically significant more decrease in the heart rate and mean blood pressure in the paravertebral group more than the epidural group. There was also equianalgesia effect regarding NIPS in both groups but longer duration of analgesia in the paravertebral group. Conclusion :Thoracic paravertebral block has equianalgesia effect with longer duration of analgesia and less decrease in the heart rate and mean blood pressure when compared to thoracic epidural block for analgesia of tracheoesophageal fistula repair in neonates Introduction Perioperative pain treatment in neonates is often insufficient.the mean reason for this is fear by the anesthetists of harming patients by cardio-respiratory depression from over dose of narcotics ().Most anesthetists would agree that there is considerable pain after thoracotomy and that excellent analgesia is required (2). However, the ideal method has not yet to be developed. Over the past twenty years regional analgesia became an inseparable part of paediatric pain relief (3). It has been shown that it depress the stress response better than any other form of anaesthesia and analgesia (4). Regional analgesia for thoracotomy in neonates has many advantages; it reduces the need for systemic opioids, it facilitates early recovery and promotes good post operative respiratory functions (5). In neonates specific factors influence regional analgesia and must be noted. There is less liver blood flow and immature enzyme, less-feto glycoprotein and albumin and right to left shunt. This will lead to easier accumulation, increased free fraction in addition to rapid absorption,compare to adults. Newer drugs such as ropivacaine can be used as they have less carditoxicity than bupivacaine (6). The technique of epidural block is similar to that in adults with use of loss of resistance technique to identify the epidural space, however the technique must be very delicate to avoid injury of the spinal cord particularly in the thoracic epidural approach. Epidural analgesia although effective, it may has some side effects. Paravertebral block is an alternative technique that may provide analgesia for thoracotomy and upper abdominal surgery and started to be used in the past decade for perioperative analgesia (7). The aim of this study was to compare a single shot thoracic paravertebral and epidural block for analgesia of tracheoesophageal fistula repair in neonates. Patients and methods This study was carried out on 24 neonates candidate for tracheoesophageal fistula repair, they were randomly allocated after AJAIC-Vol. (8) No. 4 December 25

2 8 thorough history taking and careful examination and investigation to exclude those with other congenial anomalies or coagulation abnormalities and those on mechanical ventilation before operation. They were divided into two groups; group I (paravertebral group) and group II (Epidural group). After standard monitoring of ECG, heart rate,non invasive blood pressure, oxygen saturation and temperature, Anesthesia was induced with sevoflurane followed by endotracheal intubation. Adequate depth of anaesthesia was maintained by sevoflurane concentration to keep heart rate and blood pressure within % of base line. Then regional analgesia was achieved as follow ; Group I ; single shot right thoracic paravertebral block at the level of either T5 or T6 according to the ease of performance using a tuohy needle 23 G and loss of resistance syringe and injection of ropivacaine.375% with total volume of ml /kg body weight. Group II ; Single shot thoracic epidural block with a tuhoy needle 23 G at the level of either T5 or T6 according to the ease of performance and injection of ropivacaine.375% with a total volume of ml/kg body weight. Anesthesia was maintained with sevoflurane to keep adequate depth of Anesthesia by keeping heart rate and pulse not more than % of the base line, we planned to extubate all patients, any patient with indication for post operative mechanical ventilation was excluded from the study. Measurements : - Mean blood pressure and heart rate before operation and 3 minutes interval for 6 hours including operative time in both groups 2- Mean concentration of sevoflurane minutes of sevoflurane% concentration multiplied by the sevoflurane % concentration divided by the minutes of sevoflurane used) in both groups. 3- Neonatal infant pain Score (NIPS) (8)Table I, which is a point score, is the worst pain, no pain less than 4 is mild pain measured at 3 minutes interval for 4 hours post operative period. Table I Neonatal Infant Pain Score (NIPS) Variable Finding points Facial expression Relaxed (neutral, restful) Grimace ( tight facial muscles, furrowed brow,chin, jaw) No cry Whimper ( mild moaning, intermittent) cry Vigorous crying (loud scream, if intubated it depends on 2 patient facial movement) Relaxed (usual pattern of this infant) Breathing pattern Change in breathing (irregular, faster than usual, gagging, breath holding) Relaxed (no rigidity) Arms Flexed /extended / tense straight arms, rigid and /or rapid extension and flexion) Relaxed ( no rigidity) Legs Flexed/ extended /tense straight arms,rigid and or rapid extension and flexion) State of arousal Sleep /awaking quiet peaceful sleep or alert and settled) Fussy, alert, restless Within % of the base line Heart rate -2% of the base line More than 2 % of the base line 2 Oxygen saturation No additional oxygen required to maintain saturation Additional oxygen required to maintain saturation AJAIC-Vol. (8) No. 4 December 25

3 9 Results The mean body weight in group I was 2.8±.3 kg, whereas it was 2.7±.37 kg, there was no statistically significant differences in the mean body weight in both groups. The mean heart rate as beat per minute before induction and 3 minutes interval after paravertebral block for 6 hours in group I was 45±4.3, 23.2±5.4, 2.3±2.3,8.6±5.4,2.5±2.,9.2±3.2, 23.2±.2,9.6±3.4,2.4±.2,2.3±2., 27.±3,24.4±,25.2±2.3 consequently (Table II) There was statistically significant reduction in the heart rate after paravertebral block at all time of measurements when compared to pre induction heart rate. The mean heart rate as beat per minute before induction and 3 minute interval after epidural block in group II was; 47.4±2.3, 2..3±3.4, 5.3±2.3,.4±3.2,9.2±5.2,5.4±.9,7.±2., 6.5±.2,5.4±2.,9.4±.2,2.3±.2, 9.3±3.2,2.3±.8 consequently (TableII). There was statistically significant decrease in the heart rate at all time of measurements after epidural block when compared to the preinduction value. Patients in group II ( epidural group) had statistically significant much decrease in heart rate when compared to patients in group I (Paravertebral group) at all time of measurements after induction. 47.2±.2, 43.3±2.3, 4.4±.7, 4.± ±3.2, 37.2±.8, 37.6±, 35.9±., 38.4±2., 4.±.7, 4.2±.2, 42.3±.2, 4.2±2.2 consequently (Table II). There was statistically significant drop in the mean blood pressure at all time of measurements after paravertebral block in group I. The mean of mean blood pressure in mmhg in group II before induction and at 3 minutes interval for 6 hours was ; 46.9±.9, 4.2±.2, 37.3±.2, 34.5± ±.5, 35.2±.4, 34.2±.6,33.2±3., 35.±., 34.2±., 38.7±2.,37.±.8, 38.3±2. consequently( Table II). There was statistically significant drop in the mean blood pressure at all time of measurements after epidural block when compared to the pre induction value. There was statistically significant much decrease in the mean blood pressure after epidural block in group II than after paravertebral block in group I at all time of measurements The mean concentration of sevoflurane in group I was 2.±.34 % whereas it was.9±.8 % in group II. There was no statistically significant differences in the mean sevoflurane concentration in both groups The mean of neonatal infant pain score (NIPS) at 3 minute interval for 4 hours post operative assessment in both groups are shown in table III The mean of mean blood pressure in mmhg in group I before induction and at 3 minutes interval for 6 hours was Table II: Mean heart rate and blood pressure in both groups. Mean heart Mean heart Mean blood Time of rate in rate in pressure in measurements group I group II group I Before 45± ± ±.7 3 minutes 23.2±5.4 * 2.3± ±2.3 * 6 minutes 2.3±2.3 * 5.3±2.3 4.±2. * 9 minutes 8.6±5.4 *.4±3.2 4.±2. * 2 minutes 2.5±2. * 9.2± ±3.2 * 5 minutes 9.2±3.2 * 5.4± ±.8 * 8 minutes 23.2±.2 * 7.± ± * 2 minutes 9.6±3.4 * 6.5± ±. * 24 minutes 2.4±.2 * 5.4± ±2. * 27 minutes 2.3±2. * 9.4±.2 4.±.7 * 3 minutes 27.±3 * 2.3±.2 4.2±.2 * 33 minutes 36 minutes * significant P< ± * 25.2±2.3 * 9± ± ±.2 * 4.2±2.2 * Mean blood pressure in group II 46.9±.9 4.2± ± ± ± ± ± ±3. 35.±. 34.2±. 38.7±2. 37.± ±2. AJAIC-Vol. (8) No. 4 December 25

4 2 Table III: Mean Neonatal Infant Pain Score (NIPS) at 3 minute interval for 4 hours measurements in both groups. Time of assessment of Neonatal Infant Pain Score After 3 minutes post operative After 6 minutes " " After 9 minutes " " After 2 minutes " " After 5 minutes " " After 8 minutes " " After 2 minutes " " After 24 minutes " " * significant P<.5 Group I 2.9±.2 3.±.2 2.9±.3 3.4±. 3.2±.4 3.2±.* 3.4±.5* 5.±. Group II 2.8±.9 2.9±.8 2.8±.2 3.2±.4 3.3±.2 4.6±.2 4.8±.9 4.9±.6 There was no statistically significant differences in the mean neonatal infant pain score (NIPS) at 3, 6,9,2 5, 24 minutes interval between group I (paravertebral block) and group II (epidural block). There was statistically significant lower NIPS in group I (paravertebral group) at 8, 2 minutes post operative time measurements when compared to group II (epidural group) at the same time of measurements. One patient in group I and 2 patients in group II had to be mechanically ventilated post-operatively and had been excluded from the study Discussion: Ten years ago pain treatment in neonates was of doubtful quality and effectiveness. During the last decade pain treatment in neonates has been improved by knowledge derived from studies on pain and stress (9). Safe effective analgesia for neonates undergoing major surgery remains a challenge particularly in institution where resources are limited (). Epidural analgesia used routinely in many thoracic surgery centers, it induce bilateral somatic and sympathetic nerve block. Thoracic paravertebral block is the technique of injecting local anesthetic adjacent to the thoracic vertebra close to where the spinal nerves emerge from the intervertebral foramina. This results in epsilateral somatic and sympathetic nerve blockade in multiple contagious thoracic dermatomes above and below the site of injection (). We aimed form this study to compare the single shot thoracic paravertebral and epidural block as analgesia adjuvant to general anesthesia for thoracotomy during tracheoesophageal fistula repair in neonates. showed no statistically significant difference in the mean body weight in both groups. In the present study there was statistically significant decrease in the heart rate after thoracic paravertebral block and thoracic epidural block at all time of measurements however there was statistically significant more decrease in the heart rate in the thoracic epidural block than the thoracic paravertebral block which can be explained by more sympathetic block in the epidural bock as it is a bilateral sympathetic block more than the paravertebral block which is a unilateral block. demonstrated statistically significant decrease in the mean arterial blood pressure at all time of measurements after both thoracic parvertebral block and thoracic epidural block, however more statistically significant decrease in the mean arterial blood pressure observed in the thoracic epidural group more than the thoracic paravertebral group, this can be explained also by more extent of sympathetic blockade in the thoracic AJAIC-Vol. (8) No. 4 December 25

5 2 epidural blockade than the thoracic paravertebral bock. Our result regarding this effect of epidural and paravertebral block on the heart rate and the mean blood pressure goes with that of Davis et al () during their systemic review and meta analysis comparative study of analgesia efficacy and side effects of paravertebral and epidural block for thoracotomy. We did not find any significant difference in the mean sevoflurane concentration after both thoracic paravertebral block and epidural block which reflect the equianalgesic efficacy of both bocks for analgesia of thoracotomy which reassessed post operatively by neonatal infant pain score (NIPS). demonstrated good post operative analgesia after thoracotomy for tracheoesophageal repair in neonates by using either thoracic paravertebral block or thoracic epidural block which demonsterated by neonatal infant pain score (NIPS) less than 4 points up to 5 minutes post operatively in the epidural group and up to 2 minutes in the paravertebral group. We have detected longer duration of analgesia in the thoracic paravertebral bock than thoracic epidural group. as regard the equianalgesic effect of epidural and paravertebral block for thoracotomy goes with that of Adrian () and Karamakar et al (2) during their study in major neonatal and infant surgery. and that of Davis et al () during their meta analysis study. The explanation of longer duration of thoracic paravertebral block than thoracic epidural block may be more vascularity in the epidural space than the paravertebral space which may lead to more absorption of local analgesic drug from the epidural space than the paravertebral space. Conclusion We concluded that thoracic paravertebral block with ropivacaine has equianalgesic effect of longer duration and less haemodynaemic effect when compared to epidural block for analgesia of tracheoesophageal fistula repair in neonates. References -Davis RG, Myles PS, Graham JM. A comparison of the analgesic efficacy and side effects paravertebral vs epidural blockade for thoracotomy- a systemic review and meta analysis of randomized trials. Br J Anaesth 26;96: Vas L, Naregal P, Sanzgiri S, Negri A. Some vagaries of neonatal lumbar epidural analgesia. Paed Anaesth 999;9: Hammer GB. Regional anesthesia for pediatric cardiac surgery. J Cardiothoracic Vasc Anesth 999;3: Somri M, Gaitini L, Vaida S, Collins G. Post operative outcome in high risk infants undergoing herniorraphy : comparison between spinal and general anaesthesia 998;53: Lonnqvist, Morton NS. Post operative analgesia in infants and children. Br J Anaesth 25 ;95: Ivani G, Lamuganani E, Torre M, Calevo M, De Negri P. Comparison of ropivacaine and bupivacaine for pediatric caudal block. Br J Anaesth 998; 8: Manoi K. Thoracic paravertebral block. Anesthesiology 2;95: Mainctioch N. Pain in the newborn, a possible new starting point. Euro J of Pediatrics 997;56: Dalens B. Regional anaesthesia in children. Anesth Analg 989;68: Da Lima J, Liloyd T, Howard RF. Infants and neonatal pain :anesthetist perception and prescribing pattern. Br Med J 996;33:787 -Adrian T. Epidural analgesia for major neonatal surgery. Pediatric Anaesthesia 998;8: Karmakar MK, Booker PD, Franks R. Bilateral continous paravertebral block used for postoperative analgesia in an infant having bilateral thoracotomy. Paed Anaesth ;7:469 AJAIC-Vol. (8) No. 4 December 25