Anesthesia: Essays and Researches

ORIGINAL ARTICLE
Year
: 2022  |  Volume : 16  |  Issue : 3  |  Page : 301--306

The effect of caudal anesthesia block on perioperative pain control and reduction of the anesthetic agent in pediatric infraumbilical surgery: A prospective randomized trial study


Zeana Amer Gawe1, Hasan Mohamed Isa2, Muatasem Mohamed Almashaur3, Fayza Haider4, Khadija Almulla5,  
1 Department of Anesthesia, Salmaniya Medical Complex, Government Hospital in Bahrain, Manama, Bahrain
2 Department of Pediatric, Salmaniya Medical Complex, Arabian Gulf University, Manama, Bahrain
3 Department of Anesthesia, Salmaniya Medical Complex, Arabian Gulf University, Manama, Bahrain
4 Department of Surgery, Salmaniya Medical Complex, Arabian Gulf University, Manama, Bahrain
5 Department of Anesthesia, RCSI, Dublin, Ireland

Correspondence Address:
Dr. Zeana Amer Gawe
Flat 505, Building 2040, Road 5717, Amwaj Island 257, Manama
Bahrain

Abstract

Background: Caudal epidural block (CEB) is a commonly performed neuraxial block to provide effective pain relief and analgesia in pediatric patients undergoing infraumbilical surgery. Aims: This study aimed to compare the effectiveness of adding CEB to general anesthesia (GA) in terms of intra- and postoperative pain management. Design: Prospective, randomized case-controlled trial study. Setting: Operation theater, and postoperative recovery rooms at Salmaniya Medical Complex, Bahrain. Materials and Methods: A total of 74 patients aged 2 months to 6 years with American Society of Anesthesiologists physical status classification I were recruited over a 6-month period between December 2019 and May 2020. Patients were allocated into two groups (Group A, with CEB) or (Group B, without CEB). Both groups were compared based on hemodynamic stability, pain scores, level of sedation, analgesia need, and parental satisfaction. Statistical Analysis: Data were analyzed using SPSS program. Categorical and numerical variables of both the groups were compared. Results: Patients with CEB had better hemodynamic stability during the surgical procedure based on heart rate (P = 0.039). Pain intensity scores were less in patients with CEB than those without (P < 0.001). Fentanyl consumption was lower in Group A compared to Group B at the end of surgery (P = 0.002). They were also ambulated earlier and discharged sooner than those without CEB. Parental satisfaction was 92.1% in Group A compared to 63.9% in Group B (P = 0.012). Conclusions: Adding CEB to GA for intraoperative and perioperative pain control in pediatric patients undergoing infraumbilical surgery makes it more effective, safe, and with better parental satisfaction.



How to cite this article:
Gawe ZA, Isa HM, Almashaur MM, Haider F, Almulla K. The effect of caudal anesthesia block on perioperative pain control and reduction of the anesthetic agent in pediatric infraumbilical surgery: A prospective randomized trial study.Anesth Essays Res 2022;16:301-306


How to cite this URL:
Gawe ZA, Isa HM, Almashaur MM, Haider F, Almulla K. The effect of caudal anesthesia block on perioperative pain control and reduction of the anesthetic agent in pediatric infraumbilical surgery: A prospective randomized trial study. Anesth Essays Res [serial online] 2022 [cited 2023 Feb 3 ];16:301-306
Available from: https://www.aeronline.org/text.asp?2022/16/3/301/360088


Full Text

 Introduction



In pediatric patients undergoing infraumbilical surgery, using general anesthesia (GA) alone for intraoperative and perioperative pain control requires high doses of opioids and inhalation agents along with increased postoperative analgesic use leading to prolonged phase of recovery.[1]

Caudal epidural block (CEB) is a type of regional epidural anesthesia commonly used in children including neonates.[1],[2] In infraumbilical operations, it is used as a supplement to GA and to control postoperative pain.[1],[2] It is a safe, easy, and effective type of central neuraxial block.[2],[3] The patient will be intubated and the caudal block will be performed under GA after securing the airway. The patient's position will be turned onto the lateral decubitus then a landmark-based, blind technique will be used.[2],[3] In children, the success rate with the blind technique is above 96%, but the occurrence of side effects is reported.[3]

Fentanyl administration along with a volatile anesthetic, namely, sevoflurane is a well-established method for maintaining intraoperative GA in children undergoing pediatric surgery.[4],[5] Yet, CEB is performed using bupivacaine 0.5% with a concentration of 0.25% and a volume of 1 mL.kg−1. This can lead to reduction of the sedative-hypnotic requirement of GA in addition to its analgesic properties and the significant postoperative pain relief.[5],[6],[7]

The quality and the level of CEB are dependent on the dose, the volume, and the concentration of the local anesthetic drugs.[6],[8] The analgesia duration has been shown to depend on the level of cranial spread of the local anesthetic drug injected into the caudal epidural space.[2],[6],[8]

Many studies tackling CEB regional anesthesia have been published from neighboring countries to Bahrain and worldwide.[5],[6],[9] Up to our knowledge, no studies were published from Bahrain. Moreover, there is no consensus among the anesthetists on the importance of adding CEB to GA in children undergoing infraumbilical surgery and it depends on their experience and preference.[9],[10] This study aimed to compare the effectiveness of GA with CEB with that of GA alone in terms of intra- and postoperative pain management in pediatric patients undergoing infraumbilical surgeries in Bahrain.

 Materials and Methods



Ethical approval

This study was ethically approved by the Secondary Care Medical Research Subcommittee, Salmaniya Medical Complex (SMC), Government Hospitals, Kingdom of Bahrain (IRB approval number: 123311219, approved date: December 31, 2019). Written informed consent which includes the use of patient's data for research and educational purposes was obtained from all the patients'/control's parents/guardians before the intervention. This study followed the guidelines laid down in the Declaration of Helsinki of 1975, and as revised in Edinburgh 2000. This clinical trial has been registered in BioProduct database (Registration number: PRJNA857189; URL: http://www.ncbi.nlm.nih.gov/.bioproject/857189).

Study design and setting

This was an observational, experimental, prospective, open-level, parallel-group randomized trial study performed at the anesthesia department, SMC, Kingdom of Bahrain, over a 6-month period between December 2019 and May 2020. SMC is the main training hospital affiliated with the Arabian Gulf University.

Study population

Consolidated Standards of Reporting Trials checklist was used for enrolment and allocation of patients. Children aged between 2 months and 6 years who were undergoing infraumbilical surgeries with the American Society of Anesthesiologists physical status class I were randomly allocated to either Group A (GA with CEB) or to Group B (GA without CEB).

Patients with a contraindication to CEB such as sacral anomaly, bleeding diathesis, patients with neuromuscular disease, or those who were hemodynamically unstable were excluded from the study.[9],[10],[11]

Simple randomization was done to select patients who will receive CEB from the daily surgical list. This trial was not blinded. In terms of the sample size determination, for a study power of 80% and a probability of type I error of 5%, a total of 74 patients were required for the study.

Patients were chosen for the study and were allocated into two groups of patients each (Group A and Group B). Patients in Group A received GA with CEB (bupivacaine 1 mL.kg with a concentration of 0.25%) (n = 38), while patients of Group B received GA alone without CEB (n = 36) who were used as controls.

Procedure technique

Once the patient was shifted to the operation theatre, data about patient's age, sex, weight, height, the type of surgery that will be performed, and the type of anesthesia technique planned were recorded in the anesthesia charts in details. All the patients were premedicated 30 min before the surgery to ensure a smooth parental separation.[2],[3],[6],[9] The patients were monitored in a standard manner including the use of a noninvasive blood pressure cuff, peripheral oxygen saturation (SpO2) measurements, and a three-lead electrocardiogram. A 22-gauge intravenous (i.v.) catheter was inserted into a small vein in the dorsum of the hand then 5% dextrose and 0.45% sodium chloride solution (3–4 mL.kg−1.h−1) was started i.v. Then, the GA was induced using 8% sevoflurane as inhalation anesthetic agent with the minimum alveolar concentration (MAC) value of 1.8 MAC and 100% oxygen inhalation, then fentanyl (1–2 μg.kg−1) along with 50% oxygen and 50% air was used for anesthesia maintenance.[2],[5],[6],[9]

After the eyelash reflex disappeared, the intubation was done using an adequately sized endotracheal tube or laryngeal mask depending on the type and duration of the surgery.[12],[13],[14] After that, the patient was connected to the anesthesia device (Maquet Flow-I, Sweden).

Patients in Group A received CEB under GA. After securing the airway, the child was turned onto the lateral decubitus, and CEB was introduced via a landmark-based, blind technique.[9] A 22–25-gauge hypodermic needle (GE Datex Ohmeda, USA) was used. Then, the surgery was started after 20 min from the GA induction. Patients in Group B were taken directly to the surgery under GA alone.

The vital signs and the important hemodynamic variables were recorded for all patients like heart rate, systolic blood pressure, diastolic blood pressure, SpO2 throughout the intraoperative period, and the duration of the operation. Pain score and side effects were recorded. The Children's Hospital Eastern Ontario Pain Scale (CHEOPS) is a behavior pain scale in young children which is used for evaluation of postoperative pain which can assess the effectiveness of interventions in reducing the pain and discomfort. CHEOPS score is a sum of six parameters (cry, facial, child verbal, torso, touch and leg parameters). The score is ranging from 0 to 2 or 1 to 3 assigned to each activity and the total score ranges between 4 to 13. Values above 5 is considered as the presence of pain. The Face, Legs, Activity, Cry, consolability (FLACC) scale is a measurement to assess pain for children between the age of two months to seven years which is designed for individuals who are unable to communicate their pain. The scale is scored in a range of 0 to 10, with 0 representing no pain while 10 is a maximum pain.[14],[15] These scales were developed by Hicks et al. by evaluating the facial expressions of the child.[15] The presence and the severity of pain were identified. The scale score ranges from 0 to 10, where '0' indicates no pain and above “7” to “10” indicates significant pain. The patients' 24 h pain status and whether they experienced any side effects such as nausea, vomiting, or difficulty urination were queried by the anesthesiologist. Before the patient was discharged, the use of the scale was explained to the parents by the anesthesiologist in a thorough manner and was shown in practice.

Unsuccessful interventions and complications such as hypotension were recorded for all patients in both groups. However, this approach can cause a delay in mobilization by creating complications such as urinary retention and lower extremity numbness as a central neuraxial block is used.[16],[17],[18]

Patients were observed by nurses in postanesthesia care unit (PACU) and the anesthesiologist helped in the evaluation of the pain and sedation. The observation also aimed to record the scores based on the Ramsay Sedation Scale.[5] Postoperative side effects such as postoperative nausea and vomiting, hypoxia, pain, and changes in electrocardiogram were studied. The effects such as sedation and hypotension due to CEB and fentanyl were studied during the immediate postoperative period for the first 6 h. The consumption of fentanyl and sevoflurane is recorded at the start and the end of the operation.

Anatomy

The sacrum is roughly a form of an equilateral triangle, with its base identified by feeling the two posterosuperior iliac processes and the corresponding caudal summit of the sacral hiatus.[17] The sacral hiatus is located at the caudal end of the median crest and is formed because of the 5th sacral vertebra (S5) laminae fusion failure.[2],[3],[8],[9],[19]

To locate the sacral hiatus and to achieve a successful caudal block, sacral corneal palpation is crucial. The sacral canal is continuous along with the lumbar epidural space. It contains the nerve roots of the cauda equina, which leaves it through the anterior sacral foramina. During CEB, leakage of a local anesthetic agent (LA) through these foramina explains the high quality of analgesia, and is attributable to the diffusion of LA along with the nerve roots. The spread of analgesia can be enhanced above thoracic vertebrae level (T8–T9) by increasing injected LA volume.[2],[6],[18],[19]

Bupivacaine is a preferred local anesthetic to use in the caudal block due to its longer sensory block, low central nervous system toxicity, and shorter motor block. It produces localized anesthesia by blocking the transmission of action potential in sensory, motor, and sympathetic nerve fibers. Bupivacaine also inhibits the passage of sodium through voltage-sensitive ion channels in the neuronal membrane.[18],[19],[20]

Subarachnoid space terminates in infants at S3 while in adults and children at S2. In neonates, the distance between the sacral hiatus and the dural sac is around 10 mm.[2],[18] Yet, there is a significant interindividual variability in children. The contents of the sacral canal are similar to those of the lumbar epidural space, predominantly fat, and epidural veins. Epidural fatty tissue in children is looser and has more fluids than in adults which favors LA diffusion.[2],[6],[9]

Statistical analysis

The raw data which were collected from case report forms were entered into a Microsoft Excel spreadsheet initially. Then, the data were transferred to and analyzed by IBM Corp. Released 2012. IBM SPSS Statistics for Windows, Version 21.0. Armonk, NY: IBM Corp, USA. Categorical and numerical variables of both groups were analyzed and compared. Data were expressed as n (%), mean ± standard deviation, or median and interquartile range (IQR) according to distribution normality. Continuous variables were compared using Mann–Whitney U-test, while categorical variables were compared using Fisher's exact test or Pearson Chi-square test. P < 0.05 was considered statistically significant. Confidence interval (CI) was set at 95%.

 Results



Of the 74 patients recruited in the study, 38 patients received CEB and GA (Group A), while 36 patients received GA alone (Group B). Demographic data are shown in [Table 1]. There has been no significant difference between the two groups in terms of sex and weight, but patients in Group B were older in age and taller. The median time from induction to incision was significantly longer in Group A (20 [IQR, 20–20] min) compared to Group B (10 [IQR, 10–10] min), P < 0.001 (degree of freedom [df] = 72, 95% CI = 9.5–10.4). Compared to Group B, Group A consumed much less fentanyl intraoperatively (10 [IQR, 10–10] μg vs. 20 [IQR, 20–25] μg) and at the end of the surgery (2.0 [IQR, 2.0–3.0] μg vs. 8.5 [IQR, 5.0–10.0] μg), P < 0.001 (df = 54.5, 95% CI = −13.4– −10.0), and P < 0.001 (df = 42.1, 95% CI = −6.3– −4.6), respectively.{Table 1}

The comparison between the children's vital signs is shown in [Table 2]. At the beginning of surgery, the heart rate was similar in both the groups, but at the end of surgery, the heart rate was significantly higher in Group B compared to Group A (120.94 ± 17.23 versus 114.63 ± 19.90 beats per min, respectively), P = 0.039.{Table 2}

The comparison between the children's pain intensity based on CHEOPS is shown in [Table 3]. In Group A, the average postoperative pain intensity at 60 min was 5.3 ± 0.9, while in Group B, it was 7.2 ± 2.1, P < 0.001.{Table 3}

Based on the Ramsay Sedation Scale with a score ranging from 0 to 6, the mean sedation score in Group A was 3.53 ± 0.98, and in Group B, it was 2.36 ± 0.96, P < 0.001 (df = 72.1, 95% CI = 0.72–1.6) [Figure 1].{Figure 1}

Based on the FLACC scale, the mean crying score in Group A was 1.5 ± 0.7, while in Group B, it was 2.7 ± 1.6, P < 0.001. The mean movement score 1 h postoperatively was 1.7 ± 1.3 in Group A compared to 2.9 ± 1.8 in Group B, P = 0.001. After 6 h postoperatively, the mean movement score in Group A was 3.1 ± 1.2, while in Group B, it was 4.8 ± 1.4, P < 0.001. Parents were satisfied by 92.1% in Group A and 63.9% in Group B with a significant difference as shown in [Table 3].

Children have been observed by nurses and anesthesiologists in PACU and they reported 100% of the children in Group B felt pain and they needed analgesic use and their mean CHEOPS score at 6 h was 8.6 ± 2.2. On the other hand, 79.9% of the children in Group A were sleepy and comfortable and only eight (21.1%) of them needed analgesics with a mean CHEOPS score was 7.2 ± 1.4.

Two patients (5.3%) who received the caudal block (Group A) developed complications, both had block failure due to blood aspiration and one of them had a dural puncture (2.6%). The risk of postoperative apnea, nausea, and vomiting is reduced in Group A as they had lower consumption of i.v. fentanyl compared to that of Group B patients. They also had less requirement of inhalation anesthesia sevoflurane (median of 0.5 [IQR, 0.5–0.7 MAC] compared to those in Group B (median of 1.5 [IQR, 1.5–2.0], P < 0.001 df = 72, 95% CI = −2.7–0.07).

 Discussion



This study showed the importance of using CEB in conjunction with GA to control pain in children undergoing infraumbilical surgeries. Pain control is a very important goal in pediatric surgery because children are very sensitive and their parents are worried.[1],[2],[21] Insufficient treatment has been demonstrated to make the following procedures more distressing.[5],[6] Furthermore, in the postoperative stage, inadequate pain management in children can lead to physiological and psychosocial repercussions.[18] In the recovery unit, the responsibility of pain evaluation is assigned to the nursing staff, who are supervised by an anesthesia trainee.[14],[15],[18]

Several techniques are available to assess pain in children. Accordingly, different types of pain control have been performed and many studies have been done to compare their effectiveness.[5],[6],[9] This study demonstrated that GA in combination with CEB is more effective than GA alone in providing postoperative analgesia in patients scheduled for infraumbilical surgery. Moreover, similar to Shamim et al. study, the 24th h FLACC mean score was significantly lower in the CEB group (P < 0.001).[14]

Similar to our study, Ben-David et al. demonstrated the role of CEB in lowering GA requirements intraoperatively and providing pain relief postoperative.[17] Caudal block reduces the sedative-hypnotic requirement in GA.[9] Cesim et al.'s study also clarified the important role of CEB in achieving postoperative pain control.[13]

The advantages of using the regional anesthesia techniques include reduction in the use of opioids and their related side effects.[22] In our study, out of the 38 children who received a CEB, only two children had complications including block failure in two patients (5.3%), blood aspiration in one patient (2.6%), and dural puncture in one patient (2.6%). This is considered as a low rate of complications. However, in a similar study done at the department of anesthesia in Children's Hospital of Chicago, northwestern university, out of 18600 children, 50 children who received CEB had complications (0.27%), while severe complications such as cardiac arrest and block failure in 1%, blood aspiration and seizure were found in only 0.02%, and dural puncture in 0.008%.[9] Like other studies, they concluded that CEB is a safe regional anesthesia technique when performed in children undergoing surgery.[5],[9] Similar to other studies, local anesthetic toxicity was not detected in our study with the use of bupivacaine in a volume of 1 mL.kg−1 with a concentration of 0.25%.[2],[18],[19]

In our trial, children who received CEB had no evidence of sedative effect of caudal analgesia. However, they experienced much less postoperative pain, agitation, and drowsiness than other children. In fact, CEB has great perioperative effects, such as early PACU discharges and parental satisfaction. Patients who received bupivacaine 1 mL.kg−1 with a concentration of 0.25% after caudal block had reduced depth of GA. As a result, children who received CEB were ambulated earlier and have been discharged sooner than those without a caudal block. Suresh et al. found that CEB had no permanent sequelae.[9]

The present study has some limitations. This study was not blinded and the sample size was small. Another limitation is that the two groups were not similar in terms of age and height at the time of recruitment. Patient selection bias might not be completely avoided in this study as the anesthetist and surgeon preferences might interfere with the choice of patients who will receive CEB. Despite these limitations, this is the first study conducted in Bahrain that focused on the importance of using CEB in conjunction with GA for children undergoing infraumbilical surgeries. This study focuses the pediatric surgeons' attention on the efficacy of caudal anesthesia in pain relief. The results are encouraging and can form a strong foundation for any future studies.

 Conclusion



Adding CEB to GA for intraoperative and perioperative pain control in pediatric patients undergoing infraumbilical surgery makes it more effective, safe, and with better parental satisfaction. CEB has a faster, more effective start of sensory and motor block with a longer duration of postoperative analgesia. It also reduces the number of anesthetic and analgesic agents used during the maintenance phase of infraumbilical surgery in patients aged 2 months to 6 years. Patients who received CEB intraoperatively required fewer hypnotics and sedatives while remaining vitally stable. CEB also had a high analgesic efficacy and produced excellent perioperative effects, including early discharge from the recovery room. Nonetheless, further studies regarding the possibility of replacing GA with CEB alone are needed.

Acknowledgments

The authors gratefully acknowledge the anesthesia department, operative theater, and pediatric wards in Salmaniya Medical Complex for their support by supplying drugs, instruments, and types of equipment.

Financial support and sponsorship

This study was supported by the anesthesia department, operation theatre, and pediatric and pediatric surgery departments in Salmaniya Medical Complex in the form of a supply of drugs, instruments, and equipment. No Financial support was provided by any agent.

Conflicts of interest

There are no conflicts of interest.

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