Abstract
Background
Inguinal hernia repair is the most common operation in infants, with well recognized anesthetic and perioperative risks. The aim was to investigate if the combination of caudal block, high‐flow nasal oxygen insufflation and intravenous dexmedetomidine sedation is suitable for infants undergoing inguinal hernia surgery.
Methods
A prospective multicenter international study was performed in three centers in Australia and New Zealand. Fifty infants less than 64 weeks post‐menstrual age undergoing inguinal hernia surgery were enrolled. Exclusion criteria were any condition that contraindicated the use of the anesthesia technique. The technique included intravenous dexmedetomidine with a loading dose of 1–2 mcg/kg over 10 min and maintenance of 0.2–3 mcg/kg/h, high‐flow nasal oxygen insufflation 2 L/kg/min with an oxygen blender, and a caudal block using 1 mL/kg 0.2% ropivacaine. The primary outcome was the successful completion of surgery without conversion to general anesthesia.
Results
Completion of surgery with the technique was successful in 41/50 (82%) infants. Care was provided by 22 anesthesiologists and 11 surgeons. Infants had a low incidence of intraoperative complications, including apnea [1 (2.4%)], bradycardia [2 (4.9%)], hypotension [2 (4.9%)], and desaturation [1 (2.4%)]. Postoperative complications included apnea [3 (7.3%)], bradycardia [3 (7.3%)], hypotension [3 (7.3%)], desaturation [4 (9.8%)]. No infants were intubated in the first 24 h postoperatively.
Conclusion
Caudal block, high‐flow nasal oxygen insufflation and intravenous dexmedetomidine sedation is a potential alternative to general anesthesia for infant inguinal hernia surgery with a low rate of complications in this small cohort of infants.
Keywords: caudal, dexmedetomidine, high‐flow, infant, inguinal hernia
1. INTRODUCTION
Inguinal hernia repair is the most commonly performed operation in infants, accounting for up to 27% of surgical procedures in infants up to 60 weeks post‐menstrual age. 1 This patient population is particularly vulnerable, with well recognized anesthetic, and perioperative risks. 2 Neonates and infants undergoing anesthesia for all types of surgery have higher perioperative risks than older children, with a critical event rate of up to 35.3%. 1 , 3
Clinical practice in Australia and New Zealand varies widely, and there is limited data on the most common anesthetic techniques for infant inguinal hernia repair. A recent subgroup analysis of the NECTARINE study showed that in infants in Europe undergoing inguinal hernia surgery, 14.2% of patients had an awake regional technique, 23.7% had general anesthesia alone and 62.1% had general anesthesia with a regional technique such as caudal block. 4 Therefore, despite the superior respiratory outcomes and reduced risk of post operative intubation with spinal anesthesia compared to general anesthesia 1 , 5 it appears that general anesthesia remains the most commonly performed anesthetic technique for infant inguinal hernia surgery. 4
The morbidities and limitations of both spinal block and general anesthesia in this patient population have prompted the consideration of other anesthetic techniques. There is a need for a safe alternative to general anesthesia where spinal block fails or anticipated prolonged surgical duration precludes its use. Spinal success rate is reported to be between 80%–91%. 6 , 7 Several groups have described the technique of sedation and caudal for surgery in infants. 8 , 9 Success rates for caudal and dexmedetomidine for infant inguinal hernia surgery have been reported to be between 86%–90% in single center studies 9 , 10 and a recent review of sedated caudal anesthesia found an overall anesthesia failure rate of 5.85%. 11
There is evidence that dexmedetomidine may have less impact on neurodevelopment than other general anesthetic agents and may even have a neuroprotective effect. 12 It has also been shown to cause less hypotension than general anesthesia, 9 which may have additional benefit in protecting infants from hemodynamic cerebral insults.
This study aimed to determine the success of a technique that avoids general anesthesia, whilst allowing for surgery longer than the typical duration of spinal anesthesia. A technique of using caudal, high‐flow nasal oxygen insufflation and intravenous dexmedetomidine sedation for inguinal hernia surgery in infants is described. The primary outcome was failure of the technique defined as need for conversion to general anesthesia.
2. METHODS
Ethics approval was granted in Australia by the Women's and Children's Hospital Human Research Ethics Committee (approval number 2021/HRE00281) and in New Zealand by the Health and Disability Ethics Committee (approval number 2022 FULL 13305). Written informed consent was obtained by parents for all participants.
A prospective multicenter international study of an alternative technique involving 50 infants at three centers: Flinders Medical Centre, Adelaide, Australia (FMC), Women's and Children's Hospital, Adelaide, Australia (WCH) and Christchurch Hospital, Christchurch, New Zealand, was conducted from March 2022 to October 2023.
Participants were infants less than 64 weeks post‐menstrual age undergoing isolated unilateral or bilateral inguinal hernia repair. Exclusion criteria were any condition that contraindicated the use of any component of the technique; contraindication to caudal anesthetic (coagulopathy, known structural abnormality), contraindication to the use of high‐flow nasal oxygen insufflation (choanal atresia, tracheostomy, mechanical ventilation at the time of surgery), or contraindication to use of dexmedetomidine (allergy). Patients were also excluded for parental or clinician refusal. Participants meeting the selection criteria were identified from elective booking lists and case note review by a member of the research team. The surgeon and anesthesiologist were contacted to ensure they agreed to participate. If the infant was suitable based on inclusion and exclusion criteria, then parents were contacted. Following a comprehensive information session with the research team, written informed consent was obtained by a clinical research assistant or principal investigator who was not part of the clinical treating team. A screening log was kept for each site.
The anesthesiologists were provided with a study flow chart (Figure S1) and the principal investigators at each site were available for advice but not present in the operating room for all cases. There was no lead in training period due to local ethical approvals, however all anesthesiologists were skilled in all three aspects of the technique.
Intravenous access was established, and standard monitoring was applied according to Australian and New Zealand College of Anesthetists' guidelines (ECG, pulse oximetry and non‐invasive blood pressure). Baseline observations including blood pressure were recorded preoperatively. Sucrose, dropped directly into the mouth or onto a pacifier, was available for infant comfort for intravenous access, caudal block insertion and throughout surgery.
Intravenous sedation was commenced after intravenous cannula insertion with 1–2 mcg/kg dexmedetomidine loading dose over 10 mins, and then a maintenance infusion commenced at a rate of 0.2–3.0 mcg/kg/h, titrated to the level of sedation at the anesthesiologist's discretion. If light anesthesia was suspected despite increasing the dexmedetomidine infusion, a remifentanil infusion could be commenced at a rate of 0.05–0.2 mcg/kg/min, again at the anesthesiologist's discretion. The optimal level of sedation aimed to achieve a sleeping immobile infant, maintain spontaneous ventilation and preserve hemodynamics. The dexmedetomidine infusion was recommended to be ceased 5–10 min before the end of surgery.
Topical anesthesia (such as EMLA®) and/or subcutaneous lignocaine 1% was applied to the sacral area prior to caudal insertion. One milliliter/kg of 0.2% ropivacaine was administered following caudal cannula insertion using the preferred technique of the anesthesiologist. A high‐flow nasal oxygen cannula was applied, and air or titrated oxygen was delivered at a flow rate of 2 L/kg/min with an oxygen blender (F&P 950™ humidification system and Optiflow™ nasal cannula, Fisher and Paykel Healthcare Ltd., Auckland, New Zealand). The Fraction of Inspired Oxygen (FiO2) was titrated at the anesthesiologist's discretion. Parents were advised of the off‐label use of this device in this study in the written parent information and consent form provided.
The primary outcome was the successful completion of surgery without conversion to general anesthesia. Secondary outcomes were duration of anesthesia, duration of surgery, total operating theater duration, duration of time in recovery (if applicable), post‐operative intubation within 24 h, degree of respiratory support required postoperatively, intraoperative and postoperative critical events (bradycardia/hypotension/desaturation/ apnea) and unexpected neonatal intensive care admission.
The outcome definitions are as follows: Conversion to general anesthesia: use of general anesthetic agents (sevoflurane, desflurane, or propofol), use of a supraglottic airway or endotracheal tube, or requirement for bag mask ventilation. Postoperative intubation within 24 h: endotracheal tube in situ after the patient has left the operating theater or reintubation within 24 h. Intraoperative and postoperative critical events: Infant having one or more episodes of: bradycardia, HR < 100BPM; hypotension, MAP <20% baseline; desaturation, Sp02 < 90% for greater than 5 min; apnea, a pause in breathing >15 s or a pause >10 s if associated with oxygen saturation <80% or bradycardia (20% fall in heart rate). Intervention: a critical event that did not resolve spontaneously and required treatment such as stimulation, administration of medication or oxygen, or positive pressure ventilation.
Intraoperatively, the treating anesthesiologist or clinical research assistant recorded general anesthetic data including medications administered, use of ultrasound for caudal insertion, time of caudal insertion and time of knife‐to‐skin, conversion to general anesthesia and critical events (bradycardia/hypotension/desaturation/apnea). Postoperatively, critical events were obtained from the case notes for the first 24 h after surgery.
Data was entered into a Research Electronic Data Capture (REDCap®) secure online database administered by the Health Data Clinical Trials unit, Flinders University, Adelaide, Australia. All hard copy records were stored in a locked cabinet at each site in accordance with local protocols.
2.1. Statistical analysis
There was no formal power calculation performed to determine the sample size as there was no pre‐existing data on which to base an accurate power analysis. Other published research using similar anesthetic techniques used 50 patients to allow some comparison. 9
Patient characteristics, anesthesia and surgery details, and intraoperative and postoperative outcomes were summarized by median and range. For categorical variables, the frequency and percentage were reported. Odds ratios of converting to general anesthesia and corresponding 95% confidence intervals were estimated using univariate Logistic regression separately for patient characteristics, anesthesia and surgery factors. All analyses were performed using R version 4.3.1 (R Foundation for Statistical Computing, Vienna, Austria).
3. RESULTS
Fifty patients were recruited at three hospitals. Enrolment details per site are detailed in Figure S2. Anesthesia was performed by 22 anesthesiologists (number of cases per anesthesiologist; median 2, range 1–6) and 11 surgeons (number of cases; median 2.5, range 1–16). All treating anesthesiologists were consultants or provisional fellows with consultant supervision. The proportion of successful completion of surgery by site is detailed in Table 1.
TABLE 1.
Proportion of successful completion of surgery by site.
| Total (n = 50) a | Baby Chix protocol N (%) b | Conversion to GA N (%) b | p‐value c | |
|---|---|---|---|---|
| Christchurch Hospital | 11 (22.0) | 8/11 (72.7) | 3/11 (27.3) | 0.58 |
| Flinders Medical Centre | 17 (34.0) | 14/17 (82.4) | 3/17 (17.6) | |
| Women's and Children's Hospital | 22 (44.0) | 19/22 (86.4) | 3/22 (13.6) |
Column percentages shown.
Row percentages shown.
p‐value from Fisher's exact test.
Patient characteristics for those infants successfully completing the study protocol and those requiring conversion to general anesthesia are listed in Table 2. 41/50 (82%) infants had successful completion of surgery with the study protocol. Nine (18%) infants required conversion to general anesthesia. The reasons for conversion were inadequate caudal anesthesia in six (12%) infants, suboptimal surgical conditions caused by hiccups in one (2%) infant, and inadequate sedation in two (4%) infants and are detailed in Table S1. Eight of these infants had an endotracheal tube inserted for airway management and one was managed with face mask ventilation.
TABLE 2.
Patient characteristics for infants successfully completing the study protocol and those requiring conversion to general anesthesia (GA).
| Patient characteristics | Study protocol (n = 41) | Conversion to GA (n = 9) |
|---|---|---|
| Male sex: N (%) | 33 (80.5) | 7 (77.8) |
| Gestational age at birth (weeks): Median (range) | 35.3 (23.0–41.0) | 37.3 (26.3–39.7) |
| Born <37 weeks gestation: N (%) | 24 (58) | 4 (44) |
| Born <28 weeks gestation: N (%) | 5 (12) | 3 (33) |
| Chronological age at surgery (weeks): Median (range) | 10.0 (0.0–20.0) | 9.0 (1.0–16.0) |
| Post Menstrual age at surgery (weeks): Median (range) | 43.3 (36.7–59.1) | 42.6 (36.0–54.0) |
| Birth weight (kg): Median (range) | 2.0 (0.5–3.8) | 2.4 (0.6–3.6) |
| Weight at time of surgery (kg): Median (range) | 3.9 (2.1–6.4) | 3.9 (2.4–7.3) |
| Supplemental oxygen at time of surgery: N (%) | 6 (14.6) | 0 (0.0) |
| Congenital cardiac disease: N (%) | 2 (4.9) | 1 (11.1) |
| Chronic lung disease: N (%) | 5 (12.2) | 2 (22.2) |
| Ever discharged from hospital prior to surgery: N (%) | 11 (26.8) | 4 (44.4) |
| Intrauterine growth restriction a : N (%) | 7 (17.1) | 2 (22.2) |
| Open surgery: N (%) | 41 (100) | 9 (100) |
| Bilateral hernia exploration/repair: N (%) | 18 (43.9) | 3 (33.3) |
Intrauterine growth restriction as diagnosed by obstetric team.
Of the 41 infants who had successful completion of surgery with the study technique, the median surgical duration was 32 min, the longest surgical duration was 94 min, and 9 (21.9%) infants had a surgical duration longer than 55 min. The anesthesia and surgical details are listed in Table 3.
TABLE 3.
Anesthesia and surgery details.
| Anesthesia and surgery details | Study protocol (n = 41) | Conversion to GA (n = 9) |
|---|---|---|
| Number of attempts at Caudal: Median (range) | 1.0 (1.0–5.0) | 2.0 (1.0–4.0) |
| Caudal ultrasound used: N (%) | 7 (17.1) | 1 (11.1) |
| Dexmedetomidine loading dose (mcg/kg): Median (range) | 2.0 (0.2–2.5) | 1.8 (0.2–2.1) |
| Dexmedetomidine Infusion dose (mcg): Median (range) | 1.0 (0.3–4.0) | 1.0 (0.0–3.8) |
| Remifentanil used a : N (%) | 0 (0) | 1 (11.1) |
| Start anesthesia to skin incision (min): median (range) | 28.0 (13.0–46.0) | 28.0 (15.0–50.0) |
| Caudal insertion to skin incision (min): median (range) | 10.0 (0.0–64.0) | 11.0 (3.0–31.0) |
| Total anesthetic time (min) b : Median (range) | 64.5 (30.0–113.0) | 90.0 (53.0–136.0) |
| Unilateral repair | 60.0 (34.0–90.0) | 90.0 (53.0–136.0) |
| Bilateral repair | 84.5 (50.0–113.0) | 90.5.0 (74.0–107.0) |
| Total surgery time (min): Median (range) | 32.0 (15.0–94.0) | 58.0 (17.0–90.0) |
| Unilateral repair | 27.0 (15.0–55.0) | 50.5 (17.0–90.0) |
| Bilateral repair | 49.0 (25.0–94.0) | 59.0 (30.0–83.0) |
| End surgery to end anesthesia time (min) c : median (range) | 3.0 (0–12.0) | 8.0 (0–28.0) |
| First analgesia after surgery (min): Median (range) | 147.0 (11.0–767.0) | 160.0 (102.0–471.0) |
| Time in PACU (min) b : Median (range) | 64.5 (13.0–249.0) | 103.0 (28.0–185.0) |
| Time from end anesthesia to discharge from hospital (h): Median (range) | 24.7 (3.2–3621.8) | 24.8 (5.6–1300.8) |
Remifentanil used as part of sedation protocol.
Time in post anesthesia care unit (PACU) data available for 38 participants (n = 12 did not go to PACU).
End anesthesia time data available for n = 28 study protocol, n = 7 conversion to GA group.
Full details of intraoperative and postoperative complications are listed in Table 4. No episodes of bradycardia were accompanied by hypotension. One infant had an unplanned neonatal intensive care unit admission for apneas requiring high‐flow nasal oxygen insufflation and was discharged home the following day. None of the fifty infants required intubation within the first 24 h postoperatively.
TABLE 4.
Intraoperative and postoperative complications.
| Study protocol (n = 41) | Conversion to GA (n = 9) | |
|---|---|---|
| Complications—Intraoperative | ||
| Apnea total: N (%) | 1 (2.4) | 1 (11.1) |
| Apnea requiring intervention: N (%) | 1 (2.4) | 1 (11.1) |
| Bradycardia total: N (%) | 2 (4.9) | 0 (0.0) |
| Bradycardia requiring intervention: N (%) | 2 (4.9) | 0 (0.0) |
| Hypotension total: N (%) | 2 (4.9) | 1 (11.1) |
| Hypotension requiring intervention: N (%) | 1 (2.4) | 1 (11.1) |
| Desaturation total: N (%) | 1 (2.4) | 0 (0.0) |
| Desaturation requiring intervention: N (%) | 1 (2.4) | 0 (0.0) |
| Complications—first 24 h post operatively | ||
| Apnea total: N (%) | 3 (7.3) | 1 (11.1) |
| Apnea requiring intervention: N (%) | 2 (4.9) | 1 (11.1) |
| Bradycardia total: N (%) | 3 (7.3) | 0 (0.0) |
| Bradycardia requiring intervention: N (%) | 2 (4.9) | 0 (0.0) |
| Hypotension total: N (%) | 3 (7.3) | 0 (0.0) |
| Hypotension requiring intervention: N (%) | 2 (4.9) | 0 (0.0) |
| Desaturation total: N (%) | 4 (9.8) | 1 (11.1) |
| Desaturation requiring intervention: N (%) | 4 (9.8) | 1 (11.1) |
| Increased oxygen or respiratory support compared to preoperatively: N (%) | 8 (19.5) | 1 (11.1) |
| Level of support | ||
| Wafting 02 for less than 1 h | 2 (4.9) | 0 (0.0) |
| Nasal specs 02 | 4 (9.8) | 1 (11.1) |
| High‐flow nasal oxygen | 2 (4.9) | 0 (0.0) |
| Unplanned ICU admission: N (%) | 1 (2.4) | 0 (0.0) |
| Postoperative intubation or reintubation within 48 h of surgery: N (%) | 0 (0.0) | 0 (0.0) |
Note: N (%) of presence of complication.
Table 5 lists post hoc analyses of characteristics that may have contributed to conversion to general anesthesia. No factors were identified as statistically significant.
TABLE 5.
Odds ratios (95 CI) of patient characteristics, anesthesia, and surgery factors on conversion to GA.
| Patient characteristics | OR (95% CI) |
|---|---|
| Male sex | 0.85 (0.15, 4.89) |
| Gestational age at birth (weeks) a | 1.01 (0.88, 1.16) |
| Born <37 weeks gestation | 0.57 (0.13, 2.43) |
| Born <28 weeks gestation | 3.60 (0.68, 19.16) |
| Chronological age at surgery (weeks) a | 1.00 (0.85, 1.19) |
| Post Menstrual age at surgery (weeks) a | 1.01 (0.88, 1.17) |
| Birth weight (kg) a | 1.05 (0.54, 2.05) |
| Weight at time of surgery (kg) a | 1.01 (0.58, 1.77) |
| Supplemental oxygen at time of surgery b | ‐ |
| Congenital cardiac disease | 2.10 (0.16, 28.02) |
| Chronic lung disease | 1.80 (0.25, 12.85) |
| Ever discharged from hospital | 2.18 (0.33, 14.36) |
| Intrauterine growth restriction | 1.14 (0.17, 7.76) |
| Bilateral hernia exploration/repair | 0.64 (0.14, 2.91) |
| Anesthesia and surgery details | |
| Number of attempts at Caudal a | 1.37 (0.66, 2.83) |
| Caudal ultrasound used | 0.61 (0.07, 5.66) |
| Dexmedetomidine loading dose (mcg/kg) a | 0.57 (0.16, 2.00) |
| Infusion dose (mcg) a | 1.63 (0.74, 3.60) |
| Caudal insertion to surgery start (mins) a | 1.01 (0.94, 1.08) |
OR for every unit increase.
OR could not be reliably estimated due to no patients in the conversion to GA group.
4. DISCUSSION
We have described a prospective international multicenter study of an alternative anesthetic technique for infant inguinal hernia repair. We have demonstrated successful completion of surgery without conversion to general anesthesia in 41/50 (82%) infants. This is in comparison to the 86%–90% success rate reported with caudal and sedation and a 80%–91% success rate with spinal anesthesia. 6 , 7 , 9 , 10 Thus, this technique has promise as an alternative to general anesthesia.
Prior to the commencement of the study, the anesthesiologists involved were not commonly using this technique, although they were familiar with the individual components. The overall success rate of 82% involving 22 anesthesiologists in three centers in two countries suggests that this technique can be performed without significant prior practice by a trained pediatric anesthesiologist with minimal prior experience and a low volume of practice in different institutions. There was no statistically significant difference in success rate between centers. It is possible this success rate could be higher in a perioperative team with greater familiarity with the technique. 10
Ultrasound use in this study was at the anesthesiologist's discretion and was only used in 8/50 (17%) patients. Ultrasound use for caudal block insertion has been shown to improve first pass success rates and reduce complications in children 13 and can provide reliable confirmation of successful needle placement. 14 Six of the patients who required conversion to general anesthesia were due to failure of adequate caudal block, and ultrasound was only used for two of these patients. Routine use of ultrasound for confirmation of needle placement in this study may have increased the success rates of the study technique.
The median duration from caudal insertion to skin incision was 10 min in infants with successful completion of surgery without general anesthesia, however three infants converted to general anesthesia due to inadequate caudal block had a skin incision time of less than 15 min after caudal block insertion. It is possible that there was insufficient time for the caudal block to take effect in these infants and these cases may have been successful with a longer time prior to knife to skin.
The study protocol included the addition of remifentanil if required for adequate sedation. Only one (2%) infant received remifentanil in addition to dexmedetomidine for sedation and this infant required conversion to general anesthesia. It is possible that some of the infants who were converted to general anesthesia may have been successful with the addition of remifentanil for sedation, however it is evident that the addition of remifentanil was not adequate to avoid general anesthesia in the one patient that received it.
Whilst the median surgical duration was 32 min, the longest operation successfully completed with the study technique was 94 min and 9/41 (21.9%) patients had a surgical duration longer than 55 min. This suggests that this technique is feasible for more complex hernia surgeries as an alternative to general anesthesia. Infants ranging from 2.3 to 6 kg had a successful completion of surgery, supporting it as an alternative technique for infants with a wide weight range and comorbidities.
Alternatives to general anesthesia for infant inguinal hernia surgery have included spinal anesthesia, alone or with additives to local anesthetic agents to prolong block duration, or insertion of a caudal catheter. 15 , 16 These techniques require an additional technical skill set compared to a simple caudal block which may preclude their use by clinicians and institutions with a lower volume of practice. In this study no surgery was converted to general anesthesia due to the caudal block wearing off despite the longest operation time of 94 min, therefore there was no need for caudal catheter placement in this study.
Only three infants who had successful completion of surgery with this technique had perioperative apneas requiring intervention, which is lower than reported by Bong et al. and similar to the GAS study. 9 , 10 , 17 Of note, compared to the GAS study, gestational age at birth was similar (35.6 vs. 35.5 weeks), and weight at the time of surgery was similar (4.1 vs. 4.2 kg). However, our study had a higher rate of infants receiving oxygen therapy immediately prior to surgery (12 vs. 2%). There were no episodes of postoperative intubation in any of the 50 infants included in this study, which is lower than other studies reporting postoperative intubation rates for either spinal, general anesthesia or caudal and dexmedetomidine sedation. 5 , 9
Whilst used in a variety of neonatal and pediatric clinical settings, this is the first report of high‐flow nasal oxygen insufflation routinely being used in infants undergoing inguinal hernia surgery in combination with caudal and dexmedetomidine sedation. The addition of an oxygen blender to the F&P 950 humidification system™ allowed anesthesiologists to titrate FiO2 to target oxygen saturations, thereby avoiding excess oxygen, of particular importance in infants with chronic lung disease or retinopathy of prematurity. The addition of high flow‐nasal oxygen insufflation in this study may explain the low rate of respiratory complications and absence of post operative intubation in this study. Oxygen blenders are not routinely fitted to the device used but are readily available.
All infants in this study had their operation via an open surgical technique, as is the surgical preference at the sites involved. There are significant anesthetic considerations dependent on the surgical technique and whilst open surgical repair remains the most common, laparoscopic techniques are increasing in incidence. 2 Laparoscopic surgery has been shown to be successful using caudal and intravenous anesthesia in previous studies. 8
Hemodynamic effects are a consideration with dexmedetomidine use in infants and children. This study had a low rate of bradycardia and hypotension both intraoperatively and postoperatively and no patients had a concomitant bradycardia and hypotension. This is consistent with other studies utilizing dexmedetomidine sedation in neonates and infants. 9
One infant who had successful completion of surgery with the technique did require overnight admission for apneas, highlighting that caution should always be maintained in postoperative monitoring according to local guidelines if implementing this or other novel techniques in this patient population.
A limitation of the study is that it was a prospective study of an intervention with potential for selection, performance and assessment bias. This study did not have a control arm to allow direct comparison to an alternative technique. This anesthetic technique relies on an adequately working caudal block, therefore the use of ultrasound to confirm local anesthetic placement may have increased the success rate of this technique. The lack of laparoscopic surgical technique in this study may reduce the generalizability of these results. There were no identifiable patient factors among the group of patients that required conversion to general anesthesia, but this is potentially due to the small sample size. Further studies of larger groups of patients may provide information about factors associated with the failure of this technique. The use of sucrose and topical or local anesthesia was not documented in this study. Similarly, Faces, Legs, Activity, Cry, and Consolability (FLACC) scores (or similar pain and sedation scales) were not recorded, these should be included in future studies. This study was limited to infants undergoing inguinal hernia surgery; it may be possible that this technique is also suitable for other infraumbilical procedures.
5. CONCLUSIONS
In our study 41/50 (82%) infants avoided a general anesthetic, with low complication rates in both those with successful completion of surgery and those that required conversion to general anesthesia. Our data suggest that it would be reasonable to conduct a prospective randomized controlled trial with a large sample size including very preterm infants comparing this technique to other established techniques. Until a randomized controlled trial is undertaken, any recommendation to use this technique is cautionary as it is based only on weak observational evidence.
The technique of caudal block, high‐flow nasal oxygen insufflation and dexmedetomidine sedation is an alternative anesthetic technique for infant inguinal hernia surgery. Utilizing this technique allows for the completion of surgeries of variable anticipated duration in a wide range of infants. It has the potential advantage of a low risk of perioperative adverse events and avoidance of general anesthesia and airway manipulation.
FUNDING INFORMATION
This project was jointly funded by grants from the Australian Society of Anesthetists (ASA), Society of Pediatric Anesthetists of Australia and New Zealand (SPANZA), the Australian New Zealand College of Anesthetists (ANZCA) Clinical Trials Network and Southern Adelaide Local Health Network (SALHN) enquiry grants (Flinders Foundation and The Hospital Research Foundation Group). Fisher and Paykel Healthcare Limited provided equipment, support and consumables free of charge. BSvUS is part funded by the Stan Perron Charitable Foundation and through a National Health and Medical Research Council Investigator Grant (2009322).
CONFLICT OF INTEREST STATEMENT
BSvUS is a section editor for Pediatric Anesthesia.
Supporting information
Figure S1: Study flow chart.
Figure S2: Enrolment details per site.
Table S1: Details for each infant requiring conversion to general anesthesia.
ACKNOWLEDGMENTS
We thank Emma King, Vanessa Scotland and Margie McKellow for their efforts in recruitment and data entry; Ivana Hunt for database management; Anna Freney and Michael Ee for their support of this project; and Jessica Cragg as consumer advisor.
Taverner FJ, Burgoyne LL, Scott‐Weekly R, et al. Caudal block, high flow oxygen insufflation and dexmedetomidine sedation for inguinal hernia surgery in infants—A prospective evaluation of an alternative anesthesia technique. Pediatr Anesth. 2025;35:147‐154. doi: 10.1111/pan.15040
Section Editor: Brian J. Anderson
DATA AVAILABILITY STATEMENT
The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions.
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Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Supplementary Materials
Figure S1: Study flow chart.
Figure S2: Enrolment details per site.
Table S1: Details for each infant requiring conversion to general anesthesia.
Data Availability Statement
The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions.