Pectoral Nerve Blocks for Transvenous Subpectoral pacemaker insertion in Children:(A Randomized Controlled Study)

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Title Pectoral Nerve Blocks for Transvenous Subpectoral pacemaker insertion in Children:(A
Randomized Controlled Study)
Authors: Ahmed Mohamed Elhaddad, MD1; Salwa Mohamed Hefnawy, MD1. ; Mohamed Abd El-Aziz,
MD2; Mahmoud Mostafa Ebraheem, M.Sc 2; Ahmed Kareem Mohamed, MD1
Affiliations:
1 Department of Anesthesia, Kasr Alainy, Cairo University / Abo Elreesh Children’s Hospital, via Al
Kasr Al Aini, Old Cairo, Cairo Governorate, Egypt.
2 Department of Anesthesia, Faculty of Medicine, Misr University for science and technology
Study Location: The work was completed at Abo Elreesh Children’s Hospital, Cairo.
Corresponding Author:
Lecturer of Anesthesia, kasr Alainy School of Medicine, Cairo University
Phone: (+20)01224042847
Email: [email protected]
Financial Support: No financial support was provided for this study.
Declaration of Interests: None of the authors have any disclosures to report.
Acknowledgments: None
The total number of pages (20), the total number of figures (4), tables (3) and word counts separately for
the abstract (218) and the text (2944).
Pectoral Nerve Blocks for Transvenous Subpectoral pacemaker insertion in Children: Randomized
Controlled Trial
Running title: PECs for pacemaker insertion
Abstract
agents, nonsteroid anti-inflammatory drugs, or paracetamol. There has been increased interest in opioid-
sparing multimodal pain management to minimize postoperative narcotic use. This study aims to assess
postoperative pain control and opioid consumption provided by pectoral nerve blocks (PECs) versus
standard postoperative pain control in pediatric patients after transvenous subpectoral pacemaker
insertion.
Method: in this randomized controlled study, forty pediatric patients presented for transvenous
subpectoral pacemaker insertion, with either congenital or post-operative complete heart block(CHB). :
Patients were randomly assigned into two groups according to the method of perioperative pain
management, Group C (control) received conventional analgesic care without any block and Group P
(pectoral) received PECs. Demographics, procedural variables, postoperative pain, and postoperative
opioid usage were compared between the two groups.
Results:: Intra-procedure, pectoral nerve blocks reduced cumulative dose of fentanyl and atracurium
with better hemodynamic profile and longer procedure time. Post-procedure, pectoral nerve blocks
reduced postprocedural pain scores, which was reflected in later first call for rescue analgesia, and lower
postoperative morphine consumption, and did not increase rates of complications in children who
underwent transvenous subpectoral pacemaker insertion.
Conclusion: Ultrasound guided PECs have a good intraoperative hemodynamic profile, reduce
postoperative pain scores, and lower total opioid usage in children who underwent transvenous
subpectoral pacemaker placement.
Keywords: Opioids; Pacemaker; Pain; Pediatrics; Pectoral nerve;Pain scale.
Introduction
Pacemaker implantation in children requires general anesthesia. Anesthetic challenges in a
complete heart block child can be bradycardia and hypotension unresponsive to conventional drugs and
directly proportional to the depth of anesthesia [1].
Because of the rich innervation of the chest wall in younger children, perioperative and
postoperative analgesia after transvenous pacemaker placement presents unique challenges. Subpectoral
pacemaker insertion's most stimulating parts include the initial incision and the expansion of the
generator pocket, which requires either increasing the depth of anesthesia or the use of the appropriate
technique for regional anesthesia [2].
Postoperative pain management routinely uses either intravenous or oral opioid agents in addition
to nonsteroid anti-inflammatory drugs (NSAIDs) and paracetamol. To minimize postoperative narcotic
use, there has been increased interest in opioid-sparing multimodal pain management to treat pain in the
pediatric population [3].
Regional anesthesia has become an integral part of the era of multimodal analgesia and enhanced
recovery after surgery in adults and pediatric populations [4]. The use of ultrasound guidance in the
practice of regional anesthesia has dramatically improved routine pediatric perioperative pain
management [5]. Pectoral nerve blocks (PECs) were first described by Blanco in 2011 [6]. The PECs is a
novel ultrasound guided fascial plane block intended to provide anesthesia and/or analgesia of the upper
anterior chest wall while avoiding some of the more serious complications associated with neuraxial
techniques or paravertebral blocks [7].
Since few studies investigated PECs results in children, we designed this prospective randomized
controlled trial to evaluate the perioperative pain control of PECs in children undergoing transvenous
subpectoral pacemaker insertion.
Materials and Methods
randomized, parallel-group, controlled trial was conducted in the cardiac catheterization laboratory.
Ethical approval and clinical trial authorization
After receiving approval from the ethical committee board (Approval number MS-316-2020) on
8 April 2021, the patient's legal guardians provided written informed consent. The trial was registered at
ClinicalTrials.gov prior to participant enrollment on 17 June 2021, and the registration number was
(NCT04931693). The protocol structure was written per the guidelines of the Consolidated Standards of
Reporting Trials (CONSORT) 2010 Statement and adheres to the Standard Protocol Items: Statement of
Recommendations for Interventional Trials (SPIRIT), The trial was carried out per the current version of
the Helsinki Declaration and Egyptian law on the protection of personal information.
Study population
We enrolled forty children of both sexes, aged from 1 to 9 years presented for transvenous
subpectoral pacemaker insertion, with either congenital or post-operative complete heart block, as
described in the flow diagram (Fig. 1).
Patients with a history of allergy to local anesthesia, previous subpectoral pacemaker insertion,
known coagulopathy, emergency procedure, or patients with rash or signs of infection at the injection
site were excluded from the study.
Intervention
Patients who met all the study’s inclusion criteria were randomly allocated into either group (C)
or group (P) of twenty patients each.
Group (C) control: Analgesics were administered intravenously to control perioperative pain.
Group (P) pectoral: was given 0.25% bupivacaine injection between the pectoralis major and
minor muscles (PECs I block) and below pectoralis minor muscle and above serratus anterior (PECs II
block) in a volume of 0.5 ml/kg divided equally between the two sites (0.25 ml/kg in each site).
Randomization and blinding:
An online randomization program (http://www.randomizer.org) was used to generate a random
list and patients were randomly allocated in a ratio of (1:1) into two study groups: Pectoral group (P)
(n=20) and conventional control group (C) (n=20). Random allocation numbers will be concealed in
opaque closed envelopes. The patients, parents, cardiologists, ICU stuffs, and investigators assessing
study outcomes were all blinded to the study group allocation.
Anesthesia and perioperative care
Complete history taking, comprehensive clinical examination, complete blood count (CBC),
coagulation profile, and CRP, as well as preoperative ECG, echocardiography, and chest X-ray, were all
part of the preoperative anesthetic evaluations. Children were given atropine 0.01mg/kg and midazolam
0.02mg/kg intramuscular 20 minutes before being admitted to the operating room (OR).
When the patient arrived at the operating room, electrocardiography (ECG), pulse oximetry
(SpO2), noninvasive arterial blood pressure, temperature, end-tidal CO2, and transcutaneous pacemaker
pads were all applied and baseline readings were taken before inducing general anesthesia with 8 vol.%
sevoflurane and 50% air in oxygen. Following the loss of consciousness, a peripheral venous cannula
was inserted. If a patient had an intravenous cannula, 1.5 mg/kg propofol was used for induction; in both
cases, atracurium at 0.5 mg/kg was given intravenously to facilitate endotracheal intubation, and fentanyl
at 2µg/kg was given to eliminate the stress response of intubation. We ventilated the lungs of patients
with 50% oxygen in air at tidal volumes of 6-8 ml/kg, adjusting the respiratory rate to keep the end-tidal
carbon dioxide concentration at 30-35 mmHg. Anesthesia was maintained with 1% isoflurane, 0.1 mg/kg
atracurium, and 0.50 µg/kg fentanyl to keep blood pressure and heart rate below 120% of baseline values.
Patient positioning and preparation for the block:
A consultant regional anesthetist performed an ultrasound-guided injection for children allocated
to the pectoral group, the chest was first prepared in a sterile fashion, and a linear ultrasound probe(S-
NerveTM; SonoSite Inc., Bothell, WA, USA) was placed on the planned side of pacemaker placement
at the level of the third rib. The pectoralis major, pectoralis minor, and serratus anterior muscles were
identified as relevant anatomy. A 22 G needle was advanced from anteromedial to posterolateral using
an in-plane technique until the fascial plane was reached, and 0.25 ml/kg of 0.25% of bupivacaine was
deposited between the pectoralis major and minor muscles (PECs I). The probe was then moved laterally
to identify the 4th rib then the needle advanced to deposit another 0.25 ml/kg of 0.25% of bupivacaine
between pectoralis minor and serratus anterior (PECs II)[10]. (Fig. 2)
Pacemaker placement
All procedures were carried out by a pediatric electrophysiologist. Following PECs, the chest was
reprepared and draped in a sterile manner, and 10 mL of contrast was injected under fluoroscopy through
peripheral lines in the right and left arms to delineate the right and left subclavian veins. A 5-cm incision
was made just below the clavicle in the left upper chest, and electrocautery was used to dissect down to
the prepectoral fascia. The pocket under the pectoral muscle was created using blunt dissection. A
micropuncture needle was used to gain access to the subclavian vein, which was then dilated to a larger
introducer sheath size. The PM lead was then advanced through the sheath to a suitable location in the
heart. After adequate and confirmed positioning, the lead was connected to the generator and attached to
the pectoral muscle. The device was placed in the pocket after sufficient irrigation with gentamicin-
infused saline. Three distinct layers were formed by closing the fascial, subcutaneous, and skin.
As the pacemaker implanted was of rate responsive type, which allows the heart rate to increase
in response to increased physical needs, so vital signs (heart rate (HR) and non-invasive blood pressure)
were taken at the start of the block, every 15 minutes intraoperatively, and every 6 hours postoperatively
for 24 hours.
After skin closure, inhalational anesthesia was discontinued and muscle relaxation was reversed
after the return of the patient’s spontaneous breathing. Patients were extubated and then transferred to
the pediatric intensive care unit (PICU) for recovery and monitoring.
Postoperative assessment and analgesic regimen:
After admission to the ICU, patients in both groups were managed according to the ICU protocol,
which included standard monitoring, IV analgesic paracetamol 7.5 mg/kg every 6 hours, and other
standard management. The Face, Legs, Activity, Cry, Consolability scale (FLACC) was assessed
immediately postoperative in the PICU and every 6 hours for 24 hours (Table 1). Rescue analgesia was
given when the FLACC scale was ≥ 4 at rest, comprising incremental intravenous morphine at a dose of
0.1mg/kg (with a maximum dose of 0.1 to 0.2 mg/kg/dose each time and repeated at 60 minutes according
to patients’ response) to maintain resting FLACC scale 4. Cumulative 24 hours analgesic consumption
was recorded[8].
Data collection
Data were collected independently by a researcher who was not aware of the treatment
assignment and was not involved in clinical care decision-making. Baseline characteristics included age,
gender, weight, and cause of complete heart block. Intraoperative data included the duration of surgery
including time for block, hemodynamic parameters (heart rate, mean arterial blood pressure), total
fentanyl, and atracurium doses. Postoperative data included Postoperative pain score, time to first rescue
analgesia, postoperative morphine consumption, and postoperative complications (nausea, vomiting,
pneumothorax, and infection).
Study outcomes
Primary outcome: Mean pain score by FLACC scale in the first 24 hours. Secondary outcomes:
time to first request of postoperative rescue analgesics, total consumption of opioids, the total dose of
muscle relaxant, perioperative hemodynamic parameters, and incidence of postoperative complications.
Statistical considerations
Sample size
The sample size was calculated using MedCalc software version 14( MedCalc Software bvba,
Ostend, Belgium). our primary outcome was the mean pain score by the FLACC scale in the first 24
hours after a pilot study was done on 6 patients of the control group and found that the mean pain score
in the first 24 hours was 3 ± 0.57 (mean ± SD), and at an alpha error of 0.05, we calculated that 36
children would give 90% power to detect a 20% (0.6) difference in the mean pain score in the first 24
hours between the two groups, the required sample size increased to 40 patients (20 patients per group)
to compensate for dropouts.
All statistical comparisons were performed using the Statistical Package for Social Science
(SPSS), version 21 (Chicago, IL, USA). Means and standard deviations (SD) were used to express
continuous quantitative normally distributed data, while median and range were used to express non-
normally distributed data. The percentages were used to express qualitative nominal data. Following
normality testing, continuous variables were compared with the t-test or Mann-Whitney U test, as
appropriate. The Chi-squared test or Fisher's exact test was used to compare categorical variables.
Analysis of variance (ANOVA) for repeated measures with Bonferroni correction was used to compare
changes over time. A P value <0.05 was considered statistically significant.
Results
Study population
A total of 40 children met the inclusion criteria and were enrolled in this study, (20 in each group).
Group C (control) received conventional analgesic care without any block and Group P (pectoral)
received PECs. Throughout the study, no patients were excluded (Fig. 1).
There were no statistically significant differences in baseline characteristics between the two
groups (Table 2).
Primary outcome
Mean pain score showed a significant decrease in the pectoral group than the control group (mean
values (95% CI) for group P and group C respectively (0.54 [0.40-0.73] and 3.52 [3.16-3.72]),(p ≤
0.001)(Table 3 & Fig. 4).
Other outcomes
For intraoperative variables, The mean duration of surgery in group P was statistically
significantly longer than in group C with a P value = 0.032. The mean cumulative dose of fentanyl and
atracurium were statistically significantly less in group P than in group C with a p-value of 0.040 & <
0.001 respectively (Table 2).
As regards hemodynamic Parameters, (Mean Arterial Blood Pressure (MAP) and Heart Rate
(HR)) were measured at baseline (T0), skin incision (T1) then every 15 minutes until the patient is
extubated then every 6 hours following extubation, Our study showed that there was no significant
difference between two studied groups at T0 (p=1.00), but there were statistically significant differences
at each time point from T1 to T24 between the two study groups (p < 0.036) with higher values at control
versus pectoral group (Fig. 3).
For postoperative variables, the postoperative FLACC pain scale was measured at 0, 6, 12, 18,
and 24 hours after the procedural end. When compared to the control group, the pectoral group
experienced statistically significantly less pain, at all-time points (Table 3). Postoperative mean
cumulative morphine dose was statistically significantly less in group P than in group C with a p-value
of 0.022 (Table 2).
The first request for rescue analgesia was later in the pectoral group than in the control group
with a median time in the control group of 2 hours versus 7 hours in the pectoral group. (Table 2).
There was no statistically significant difference in the incidence of complications such as
postoperative nausia and vomiting (PONV), pneumothorax, and infection between the two groups (Table
2).
Discussion
Our randomized controlled study aimed to evaluate the differences in perioperative pain control
and opioid consumption in the first 24 provided by ultrasound guided PECs versus standard postoperative
pain control in children who underwent transvenous subpectoral pacemaker insertion.
In the current study, the primary outcome Mean pain score shows a significant decrease in the
pectoral group than in the control group.
Pre-procedure, there were no statistically significant differences between both groups regarding
age, weight, gender, and cause of complete heart block. Intra-procedure, PECs reduced cumulative dose
of fentanyl and atracurium with better hemodynamic profile and longer procedure time. Post-procedure,
PECs reduced postprocedural pain scores, which was reflected in later first call for rescue analgesia, and
lower postoperative morphine consumption, and did not raise the number of complications in children
who underwent transvenous subpectoral pacemaker insertion.
All device implants in pediatric patients are done under general anesthesia, and many of these
patients have high-risk cardiorespiratory comorbidities that make general anesthesia more dangerous. [10].
Effective anesthesia and hemodynamic stability are important goals to be maintained during the
pacemaker insertion procedure in pediatric patients with complete heart block because during the
procedure there is always a risk of vascular tone loss and diminishing cardiac output. Therefore, induction
and maintenance of general anesthesia in a patient with a complete heart block should be done very
carefully [1]. Additionally, the rich innervation of the chest wall in younger children undergoing
subpectoral placement of pacemakers can lead to greater pain due to the dissection of pectoralis muscle
fibers [2].
Adequate postoperative analgesia for cardiac procedures helps in early recovery, ambulation, and
reducing post-operative complications. Pain in post-intervention cardiac patients is typically treated with
nonsteroidal anti-inflammatory drugs, Paracetamol, and opioids, with their associated side effects and
delayed recovery [11].
The growing awareness of the risks associated with narcotic use in pediatric and adolescent
populations has prompted researchers to investigate opioid-free postoperative pain management with
regional anesthesia. PECs I and PECs II were introduced by Blanco [5] for analgesia in breast surgery in
2011 and have since been adapted to various chest wall surgeries such as thoracotomies and device
placements in adults.
There is always the risk of infection when it comes to hardware placement, and we were
concerned about re-preparation between the PECs and device placement because they are in the same
location. In our current practice, PECs were performed using a sterile technique, followed by additional
surgical preparation to ensure a sterile field before the first incision for device implantation. Our data
revealed a statistically significant increase in the operating room and procedural times in the pectoral
group, this may be due to the additional PECs procedure could lengthen the total OR and procedural time.
We discussed eliminating the extra surgical preparation, which could further reduce operating room time.
Relevant case reports studied device implantation under PECs in adults and include, PECs along
with an intercostal nerve block and intravenous sedation for the sub-pectoral placement of a cardiac
resynchronization therapy device (CRTD) [12], PECs for implantable cardioverter defibrillator(ICD)
insertion in young patients with Duchenne muscular dystrophy with intercostal block and intravenous
sedation [13], PECs for implantable cardioverter defibrillator (ICD) in a super obese patient [14], relocation
of an infected cardiac pacemaker generator under PECs using intravenous midazolam [15], and PECs were
used alone as the…

Pectoral Nerve Blocks for Transvenous Subpectoral pacemaker insertion in Children:(A Randomized Controlled Study)

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opioids

pacemaker

pain

pediatrics

pectoral nerve

pain scale