Pediatr Surg Int

DOI 10.1007/s00383-016-4027-6

ORIGINAL ARTICLE

Regional block via continuous caudal infusion as sole anesthetic

for inguinal hernia repair in conscious neonates
Claudia M. Mueller1 • Tiffany J. Sinclair1 • Megan Stevens1 • Micaela Esquivel1 •

Noah Gordon2

Accepted: 14 November 2016

Ó Springer-Verlag Berlin Heidelberg 2016

Abstract for elective surgeries in infants. This successful regional

Purpose The use of general anesthesia in young children approach obviates the use of general anesthetic which
has come under increasing scrutiny due to its potential reduces post-operative recovery time and avoids concerns
long-term neurotoxic effects. Meanwhile, regional anes- for neurotoxicity.
thesia for surgical procedures in neonates has many
advantages, including preservation of respiratory status and Keywords Regional anesthesia
Continuous caudal
faster return to feeding. We describe the successful use of infusion
Neonatal surgery
3% 2-chloroprocaine administered via continuous caudal
infusion as the sole anesthetic agent during elective sur-
gical procedures in infants. Introduction
Methods A retrospective chart review of all patients who
underwent elective surgical procedures under continuous Surgical procedures in the neonatal period are becoming
caudal regional anesthetic at a single institution was per- ever more frequent as improvements in neonatal care allow
formed. Thirty patients (27 males, three females) were for the increased stability and survival of premature infants.
identified: 28 patients underwent inguinal hernia repairs. Inguinal hernia repair is a routine pediatric surgical pro-
Caudal anesthesia was established via continuous infusion cedure, and preterm neonates have a higher incidence of
of 3% 2-chloroprocaine through an indwelling catheter. repair than older children [1]. Traditionally, inguinal hernia
Results Successful analgesia by regional block alone was repair has necessitated the use of general anesthetic for
achieved in all patients for the duration of each surgical sedation, however, there is mounting data for post-opera-
procedure without need for rescue anesthesia. Mean oper- tive respiratory compromise and neurotoxicity associated
ative time was 49 min. Patients were able to return to with general anesthesia in infants. Increased post-operative
feeding immediately after surgery and were ready for dis- respiratory events, such as apnea, have been demonstrated
charge home within that day. in infants undergoing inguinal hernia repair with general
Conclusion Continuous caudal infusion of chloroprocaine anesthesia [2–5]. Furthermore, the incidence of respiratory
is a safe and effective way to maintain adequate analgesia compromise seems to be associated with prematurity [2, 5].
Of more pressing concern to parents and neonatologists are
the potential side effects of general anesthesia on the
& Claudia M. Mueller developing brain [6–8]. In addition to multiple animal
clmueller@lpch.org studies demonstrating neurotoxicity as a result of general
1
anesthetics, human studies have shown adverse cognitive
Division of Pediatric Surgery, Stanford University School
and behavioral outcomes after early exposure to general
of Medicine, 300 Pasteur Drive, Alway Building M116, MC:
5733, Stanford, CA 94305, USA anesthesia [9–12].
2 To minimize these potential complications of general
Department of Anesthesiology, California Pacific Medical
Center, 3700 California Street, San Francisco, CA 94118, anesthesia, anesthesiologists have begun to explore other
USA methods of obtaining analgesia for elective surgical

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procedures in the neonatal period [13–15]. Regional block onset was suggested by lack of leg movement, a
anesthetic, often applied via one-shot caudal, has been dermatomal level was assessed by evaluating for response
considered as an alternative form of analgesia in the first to cool temperature challenge (application of a room
weeks of life [15]. It appears to be safe and provide ade- temperature metal surface such as laryngoscope handle/
quate analgesia during infra-umbilical operations [15–18]. blade, or alcohol prep swipe to skin) or pinprick challenge
Single dose caudal block, however, may not be able to (response to sterile tongue depressor broken in half). If
provide analgesia that is fully adequate for the duration of needed, an additional dose (four doses total, 2 ml/kg) was
an operation [19]. Continuous caudal anesthesia would administered to achieve a dermatomal level of at least T-10
ameliorate that concern. Administration of analgesia with (umbilicus). After being positioned for surgery with careful
this method has been demonstrated to be technically fea- attention to padding of the lower extremities and protection
sible in inguinal hernia repair in preterm infants [20, 21], of pressure points, the adequacy of surgical block was once
but outcomes have not been examined. again assessed before incision.
In this paper, we describe a novel method of applying Analgesia was maintained by an infusion rate of 1.5 ml/
regional anesthetic via continuous caudal infusion without kg/h of the same anesthetic solution. No analgesics, seda-
sedation in conscious neonates undergoing inguinal hernia tive-hypnotics, or anesthetics were administered other than
repair and evaluate post-operative outcomes. the ester local anesthetic chloroprocaine via the epidural
(continuous caudal) catheter. Oral sucrose solution
administered via pacifier and background soothing noise
Materials and methods (playing lullabies) were used throughout the procedure to
keep the infant calm. Manual restraint of the upper
A retrospective chart review of all neonatal patients who extremities, either by the anesthesiologist or with soft
underwent elective surgical procedures under regional gauze straps, was used as needed to prevent excessive
anesthetic alone between March, 2012 and March, 2015 upper torso movement.
was performed. No exclusions were made based on history
of chronic lung disease, apneic episodes, or congenital
heart disease. Patients’ charts were reviewed for demo- Results
graphic data, initial diagnosis and surgical intervention,
presenting symptoms, complications of surgery and anes- Demographics
thetic and subsequent follow-up at clinic.
Regional anesthetic was applied via continuous caudal Thirty patients (27 males, three females) who had surgery
infusion in the operating room in the following fashion. under continuous caudal block were identified, 28 patients
Patients were placed in left lateral position, with head underwent inguinal hernia repairs (20 bilateral, five with
placed under towel for soothing effect and nurse assisting circumcision). 23 patients were born prematurely. Their
with positioning to accentuate lumbar kyphosis and main- post-conceptional age at time of surgery ranged from 34 to
tain application of a sucrose-sweetened pacifier. The back 58 weeks (mean 41 weeks). Mean weight at time of sur-
was prepped with alcohol/chlorhexidine solution and gery was 3.3 kg (Table 1). Eight of the patients had known
draped in the usual sterile fashion. A 2-mm skin nick was pulmonary disease prior to surgery, although only two were
made at the approximate location of the sacral hiatus using on oxygen at the time of the procedure.
surface anatomic landmarks, and 22-gauge angiocath was Successful analgesia by regional block alone was
advanced using sterile technique with the epidural space achieved in all patients for the duration of each surgical
identified by loss of resistance with passage of a short bevel procedure without need for rescue anesthesia. Mean oper-
needle through the sacrococcygeal membrane. A test dose ative time was 49 min. Mean time for induction of
of 0.1 ml/kg of epinephrine solution diluted to concentra-
tion of 5 lg/ml was administered after negative aspiration
for blood or CSF, with no change in heart rate or T wave Table 1 Patient characteristics and operative details
morphology on ECG tracing used as signs to confirm a Male, n (%) 27 (90)
negative test. The catheter was secured with steristrips, Gestational age (weeks), mean (range) 28 (24–35)
tegaderm, mastisol, and paper tape, with tubing along the Post-conceptual age (weeks), mean (range) 41 (34–58)
back secured lateral to the anticipated electrocautery unit Weight at surgery (kg), mean (range) 3.3 (1.9–5.4)
grounding pad site. The catheter was then dosed with Operative time (min), mean (range) 49 (22–105)
preservative-free 3% 2-chloroprocaine in divided doses, in
Time for anesthesia induction (min), mean (range) 48 (28–76)
increments of 0.5 ml/kg/dose, waiting approximately
Time to leave room (min), mean (range) 33 (14–42)
3–5 min between each dose. After three doses, if motor

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anesthesia was 48 min. The time for induction trended waiting approximately 3–5 min between each dose with an
down over time, but the difference was not significant. additional fourth dose if needed to achieve a dermatomal
Mean time to leave the room after closure was 33 min level of at least T-10 Initial onset was 3–5 min and early
(Table 1). All patients returned to the ICU extubated and motor effects such as diminished hip flexion could be seen
with stable vital signs. Patients were able to return to in some babies in our series while the catheter was being
feeding immediately after surgery and were ready for dis- secured. In general, we were able to begin securing the
charge home within that day. No post-operative apneic lower extremities with little resistance and good sensory
episodes or desaturation events were noted. block to pinch or cold stimulation by 7–10 min. Full sur-
Only one complication was noted. In one patient, the gical motor blockade was consistently present within
respiratory drive was depressed sufficiently upon initial 10–15 min of administering the first dose of 2-chloropro-
loading dose that intubation was required although no caine through the indwelling caudal catheter. The rapid
additional anesthetic agent was given. The case proceeded onset of action of 2-chloroprocaine for analgesia makes it
without incident and the patient was extubated and taken an ideal choice for a regional-only anesthetic approach and
back to the NICU without difficulty. allows for easy titration of the dose to quickly increase
All patients were noted to be doing well clinically at effectiveness of the block during the procedure.
post-operative follow-up in clinic at approximately To date, a regional-only anesthetic approach has failed
2 weeks. There have been no recurrences or other com- to gain widespread acceptance by surgeons for elective
plications on long-term follow-up. infra-umbilical surgical procedures. In particular, surgeons
may show concern that caudal anesthesia without sedation
does not prevent excessive upper torso movement or
Discussion increases in intra-abdominal pressure. Sudden changes in
intra-abdominal pressure during inguinal hernia repair, in
Given the negative consequences of general anesthesia in particular, could theoretically lead to disruption of the
neonates, including post-operative respiratory compromise hernia sac and bowel herniation. In a literature review of
and neurotoxicity, parents are becoming increasingly studies using single-shot spinal anesthesia without pre-
reluctant to have their children undergo this form of emptive sedation in neonates undergoing inguinal hernia
operative analgesia unless absolutely necessary. At our repair, four studies discussed rescue analgesia and/or infant
hospital, we have developed a protocol that allows neo- restraint for intra-operative restlessness, crying, or upper
nates in the first weeks of life to undergo elective hernia extremity movement [4, 27–29]. In these studies, approx-
repair under regional block administered via continuous imately 20% of subjects necessitated additional intra-op-
caudal infusion, without the addition of other sedation. erative sedation (inhaled or IV) to treat infant restlessness.
Overall, patients tolerated both the analgesia and the More frequently, manual upper extremity restraint or sugar
procedures without adverse outcomes. The one patient who solution via pacifier was used successfully instead. In the
suffered analgesia-related respiratory depression was two studies which used either incremental caudal [21] or
extubated in the operating room and had no side effects. continuous caudal anesthesia [20], only one out of 19
Caudal infusion provided sufficient analgesia to complete subjects required rescue anesthesia during a particularly
the surgical procedure without distress in all patients. difficult hernia dissection involving the sigmoid colon.
Although initially approved as an epidural anesthetic by In our experience, continuous caudal anesthesia was
the Food and Drug Administration (FDA), several reports sufficient to obtain analgesia for the duration of the pro-
in the 1980s described irreversible neurologic injury after cedure without the need for additional sedation in all
unintentional intrathecal injection of chloroprocaine patients. Although there is a theoretical concern that
[22, 23]. The resultant neurotoxicity has been linked to the increases in intra-abdominal pressure could lead to sac
preservative sodium bisulfite, possible through the pro- disruption or bowel herniation with a regional-only anes-
duction of sulfur dioxide [22–24]. Currently, 2-chloropro- thetic approach to inguinal hernia repair, this was not found
caine is available as a preservative-free solution, and it has to be a problem in our series. As an anticipatory measure,
become increasingly popular as an epidural anesthetic. we did have close communication between surgeon and
2-Chloroprocaine is a fast acting, short duration local anesthesiologist during cases so that additional oral sucrose
analgesia used for spinal and regional anesthesia. The time solution was administered to the infant prior to and during
of onset to adequate sensory blockade has been reported to more uncomfortable parts of the procedure, e.g., manipu-
range from 4 to 30 min when used as an intrathecal anes- lation of the hernia sac. It is plausible that the use of
thetic for surgical procedures with 1–2% preparations continuous caudal, rather than single-shot regional anes-
[25, 26]. In our study, patients received 3% 2-chloropro- thesia, provides superior, and more consistent, analgesia.
caine in divided doses, in increments of 0.5 ml/kg/dose, This, in combination with careful coordination between

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surgeon and anesthesiologist, likely accounts for our suc- predisposition for underlying lung pathology. Although
cess in completing all procedures without the need for caudal anesthesia is becoming increasingly utilized for
rescue anesthesia. inguinal hernia repair in neonates to avoid the risk of post-
Our relatively long mean time to anesthesia induction of operative apnea associated with general anesthesia, it is
48 min was affected by multiple factors. Although the need frequently used in combination with sedation. Even with
to give multiple doses of 2-chloroprocaine to achieve spinal anesthesia, infants with pre-existing pulmonary
adequate sensory block was one component, the fast onset disease who also receive sedation seem to be at greater risk
of action of the drug minimizes the contribution of this of adverse respiratory complications compared with infants
factor. The largest influence to the time for anesthesia who do not receive sedation [27]. Administering caudal
induction was placement of the epidural catheter in an anesthesia using a continuous infusion, however, may
awake infant. For example, palpation of landmarks to guide eliminate the need for additional sedation, and thus
placement is more difficult in an infant with increased decrease the accompanying risks of respiratory compro-
subcutaneous adipose tissue. Or an inexperienced OR nurse mise. In our study, no post-operative apneic episodes or
may not be proficient in assisting with positioning of the desaturation events were observed.
infant during insertion. As with any new procedure, we Of course, our study is limited by the small number of
noted a decrease in the induction time consistent with a participants and by its retrospective design. Nonetheless, our
learning curve in placing the caudal catheter. Overall, we work offers strong evidence of the feasibility of a regional-
believe that the additional time added to induction out- only approach to hernia repair. Our early experience with
weighs the risks associated with general anesthesia. How- regional anesthetic administered via continuous caudal
ever, availability of pediatric anesthesiologists infusion for elective inguinal hernia repair is encouraging.
comfortable with placing caudal catheters may influence The technique appears straightforward and has proven to be
induction time or limit the use of caudal anesthesia in safe and effective when used in conscious neonates for hernia
certain centers. surgery. Therefore, we advocate its consideration as an
The evidence supporting neurotoxicity in neonates who alternative to general anesthetic, particularly in former pre-
have undergone general anesthesia is mixed. A recent mature patients who have significant pulmonary disease.
systematic review and meta-analysis demonstrated and
Compliance with ethical standards
increased risk of negative neurodevelopmental outcomes
associated with exposure to general anesthesia [30]. Funding None.
SmartTots, a collaboration between the International
Anesthesia Research Society and the US Food and Drug Conflict of interest The authors declare that they have no conflict of
Administration, whose goal is to increase the safety of interest.
pediatric anesthesia issued a consensus statement in Ethical approval For this type of study formal consent is not
November 2015 regarding the use of anesthetics and required.
sedatives in children based on preliminary data from the
General Anesthesia Compared to Spinal Anesthesia clini-
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