Clonidine added to bupivacaine in neonatal spinal anesthesia: a prospective comparison in 124 preterm and term infants

A Single Center's Experience With Spinal Anesthesia for Pediatric Patients Undergoing Surgical Procedures

PURPOSE

To perform a single institution review of spinal instead of general anesthesia for pediatric patients undergoing surgical procedures. Spinal success rate, intraoperative complications, and postoperative outcomes including unplanned hospital admission and emergency department visits within seven days are reported.

METHODS

Retrospective chart review of pediatric patients who underwent spinal anesthesia for surgical procedures from 2016 until 2022. Data collected included patient demographics, procedure and anesthetic characteristics, intraoperative complications, unplanned admissions, and emergency department returns.

RESULTS

The study cohort included 1221 patients. Ninety-two percent of the patients tolerated their surgical procedure without requiring conversion to general anesthesia, and 78% of patients that had spinals placed successfully did not receive any sedation following lumbar puncture. The most common intraoperative event was systolic blood pressure below 60 mm Hg (14%), but no cases required administration of vasoactive agents, and no serious intraoperative adverse events were observed. Post-Anesthesia Care Unit Phase I was bypassed in 72% of cases with a median postoperative length of stay of 84 min. Forty-six patients returned to the emergency department following hospital discharge, but no returns were due to anesthetic concerns.

CONCLUSIONS

Spinal anesthesia is a viable and versatile option for a diversity of pediatric surgical procedures. We noted a low incidence of intraoperative and postoperative complications. There remain numerous potential advantages of spinal anesthesia over general anesthesia in young pediatric patients particularly in the ambulatory setting.

LEVEL OF EVIDENCE

IV.

TYPE OF STUDY

Retrospective cohort treatment study.

Implementation of a spinal anesthesia and sedation protocol that reliably prolongs infant spinal anesthesia: Case series of 102 infants who received spinal anesthesia for urologic surgery

BACKGROUND

The use of spinal anesthesia in infants is seeing resurgence as an alternative to general anesthesia.

AIMS

Our primary aims are to describe our institution's experience introducing a spinal anesthesia and sedation protocol for infants undergoing urologic surgery, to describe methods of improving prolonged anesthesia, and to describe the failure rate of spinal anesthesia in these patients. Sedation was provided for some infants with intranasal dexmedetomidine ± fentanyl.

METHODS

This is a retrospective case series examining infants aged 1-<14 months who received spinal anesthesia for circumcision, orchiopexy, orchiectomy, hypospadias repair, or epispadias repair. The electronic medical record was reviewed and compared with unmatched historical controls who received general anesthesia.

RESULTS

A total of 230 patients underwent a urologic procedure; 102 patients received spinal anesthesia and 128 received general anesthesia. Length of surgical time with spinal anesthesia ranged from 4 to 189 minutes. The hospital length of stay was shorter in the spinal anesthesia group (median [IQR] of 5.3 hours [4.3, 7.2]) compared to the general anesthesia group (17.1 hours [15.6, 17.5]).The median bupivacaine dose was 0.75 mg/kg [0.67, 0.85]. There was one case in which cerebral spinal fluid was unable to be obtained, and one case that required conversion to general anesthesia after surgery had started. There were no cases of apnea, bleeding, infection, or neurologic compromise.

CONCLUSIONS

We describe the successful implementation of an infant spinal anesthesia and sedation protocol and a technique that uniquely provides prolonged surgical anesthesia with a low failure rate. We also report shorter anesthesia time, surgical time, and recovery room length of stay in patients who received spinal anesthesia compared to general anesthesia.

Clonidine for pain in non-ventilated infants

BACKGROUND

Critically ill newborn infants undergo a variety of painful procedures or experience a variety of painful conditions during their early life in the neonatal unit. In the critically ill paediatric and neonatal population, clonidine is prescribed as an adjunct to opioids or benzodiazepines aiming to reduce the doses of these drugs that are required for analgesia or sedation, or to facilitate weaning from mechanical ventilation. It has been shown that clonidine premedication might have a positive effect on postoperative pain in children.

OBJECTIVES

To assess the benefit and harms of clonidine for the prevention or treatment of procedural pain; postoperative pain; or pain associated with clinical conditions in non-ventilated neonates.

SEARCH METHODS

We used the standard search strategy of Cochrane Neonatal to search the CENTRAL, MEDLINE via PubMed, Embase, and CINAHL to December 2018. We also searched clinical trials databases, conference proceedings, and the reference lists of retrieved articles for randomised controlled trials and quasi-randomised trials. We ran an updated search from 1 January 2018 to 11 March 2020 in CENTRAL via CRS Web, MEDLINE via Ovid, and CINAHL via EBSCOhost.

SELECTION CRITERIA

Randomised controlled trials, quasi-randomised controlled trials, and cluster trials comparing clonidine to placebo or no treatment, opioids, paracetamol, dexmedetomidine, or non-pharmacological pain-reducing interventions for the management of procedural pain, postoperative pain, and pain associated with clinical conditions in preterm and term newborns.

DATA COLLECTION AND ANALYSIS

Two review authors independently planned to extract data (e.g. number of participants, birth weight, gestational age, modality of administration, and dose of clonidine) and assess the risk of bias (e.g. adequacy of randomisation, blinding, completeness of follow-up). The primary outcome considered was pain: for procedural pain, the mean values of each analgesia scale assessed during the procedure and at one to two hours after the procedure; for postoperative pain and for pain associated with clinical conditions, the mean values of each analgesia scale assessed at 30 minutes, three hours, and 12 hours after the administration of the intervention. We planned to use the GRADE approach to assess the quality of evidence.

MAIN RESULTS

Our search strategy yielded 3383 references. Two review authors independently assessed all references for inclusion. We did not find any completed studies for inclusion. We excluded three trials where clonidine was administered for spinal anaesthesia.

AUTHORS' CONCLUSIONS

We did not find any studies that met our inclusion criteria and hence there is no evidence to recommend or refute the use of clonidine for the prevention or treatment of procedural or postoperative pain, or pain associated with clinical conditions in neonates.

Hypothermia Following Spinal Anesthesia in an Infant: Potential Impact of Intravenous Dexmedetomidine and Intrathecal Clonidine

The α₂-adrenergic agonists (dexmedetomidine and clonidine) have been used in several different clinical scenarios in infants and children including sedation during mechanical ventilation, procedural sedation, supplementation of postoperative analgesia, prevention of emergence delirium, control of post-anesthesia shivering, treatment of withdrawal and prolonging of duration of neuraxial anesthesia. Hemodynamic effects including bradycardia and hypotension remain the predominant adverse effects reported with the α₂-adrenergic agonists. We report hypothermia following intravenous sedation with dexmedetomidine and spinal anesthesia with a combination of bupivacaine and clonidine in a 2-month-old infant. The potential mechanisms involved are reviewed, the causal relationship between hypothermia and α₂-adrenergic agonists is explored and interventions to avoid its development are presented.

Spinal anesthesia instead of general anesthesia for infants undergoing tendon Achilles lengthening

Spinal anesthesia (SA) has been used relatively sparingly in the pediatric population, as it is typically reserved for patients in whom the perceived risk of general anesthesia is high due to comorbid conditions. Recently, concern has been expressed regarding the potential long-term neurocognitive effects of general anesthesia during the early stages of life. In view of this, our center has developed a program in which SA may be used as the sole agent for applicable surgical procedures. While this approach in children is commonly used for urologic or abdominal surgical procedures, there have been a limited number of reports of its use for orthopedic procedures in this population. We present the use of SA for 6 infants undergoing tendon Achilles lengthening, review the use of SA in orthopedic surgery, describe our protocols and dosing regimens, and discuss the potential adverse effects related to this technique.

Comparison of postoperative analgesic effect of intrathecal clonidine and fentanyl added to bupivacaine in patients undergoing cesarean section: a prospective randomized double-blind study

Objectives. To compare the analgesic efficacy of intrathecal clonidine and fentanyl added to bupivacaine after cesarean section. Methods. Ninety patients scheduled for cesarean section under spinal anesthesia were randomly allocated to one of the three following groups to receive bupivacaine 10 mg combined with 75 µg clonidine (group C), bupivacaine 10 mg combined with 0.5 mL fentanyl (group F), and bupivacaine 10 mg combined with 0.5 mL distilled water (group P), intrathecally. The time to first analgesic request, analgesic requirement in the first 24 hours after surgery, sensory and motor blockade onset time, duration of sensory and motor blockade, the incidence of hypotension, ephedrine requirements, bradycardia, and hypoxemia were recorded. Results. The duration of anesthesia in clonidine group (275.10 ± 96.09) was longer compared to the placebo (211.73 ± 74.80) and fentanyl (192.33 ± 30.36) groups. This difference between group C versus F (P = 0.006) and P groups (P < 0.001) was significant. Similarly, the mean time to first analgesic request was also longer in group C (519.44 ± 86.25) than in groups F (277.88 ± 94.25) and P (235.43 ± 22.35 min). This difference between group C versus F (P < 0.001) and P groups (P < 0.001) was significant. Conclusion. Intrathecal clonidine 75 µg with bupivacaine prolonged the time to first analgesic request compared to fentanyl; however, the total analgesic consumption within the first 24 h postoperative was similar in fentanyl and clonidine groups following cesarean section. This trial is registered with ACTRN12611000909921 and ClinicalTrials.gov NCT01425658.

Neuraxial analgesia in neonates and infants: a review of clinical and preclinical strategies for the development of safety and efficacy data

Neuraxial drugs provide robust pain control, have the potential to improve outcomes, and are an important component of the perioperative care of children. Opioids or clonidine improves analgesia when added to perioperative epidural infusions; analgesia is significantly prolonged by the addition of clonidine, ketamine, neostigmine, or tramadol to single-shot caudal injections of local anesthetic; and neonatal intrathecal anesthesia/analgesia is increasing in some centers. However, it is difficult to determine the relative risk-benefit of different techniques and drugs without detailed and sensitive data related to analgesia requirements, side effects, and follow-up. Current data related to benefits and complications in neonates and infants are summarized, but variability in current neuraxial drug use reflects the relative lack of high-quality evidence. Recent preclinical reports of adverse effects of general anesthetics on the developing brain have increased awareness of the potential benefit of neuraxial anesthesia/analgesia to avoid or reduce general anesthetic dose requirements. However, the developing spinal cord is also vulnerable to drug-related toxicity, and although there are well-established preclinical models and criteria for assessing spinal cord toxicity in adult animals, until recently there had been no systematic evaluation during early life. Therefore, in the second half of this review, we present preclinical data evaluating age-dependent changes in the pharmacodynamic response to different spinal analgesics, and recent studies evaluating spinal toxicity in specific developmental models. Finally, we advocate use of neuraxial drugs with the widest demonstrable safety margin and suggest minimum standards for preclinical evaluation before adoption of new analgesics or preparations into routine clinical practice.

Intrathecal clonidine in the neonatal rat: dose-dependent analgesia and evaluation of spinal apoptosis and toxicity

BACKGROUND

Neuraxial clonidine is used for perioperative analgesia in children of all ages. Preclinical studies in the postnatal rat allow comparison of the relative toxicity and safety of spinal analgesics throughout postnatal development.

METHODS

Rat pups aged 3, 7, or 21 postnatal (P) days were briefly anesthetized for intrathecal injections of saline or clonidine. At each age, the maximum tolerated, antinociceptive (increased hindlimb mechanical withdrawal threshold) and antihyperalgesic (hindpaw carrageenan inflammation) doses were determined. Lumbar spinal cord sections were assessed for apoptosis and cell death (histology, activated caspase-3 immunohistochemistry, Fluoro-Jade C staining), histopathology (hematoxylin and eosin staining), and increased glial reactivity (microglial and astrocytic markers). P3 intrathecal ketamine sections served as positive controls. In additional groups, thermal latency and mechanical withdrawal threshold were measured at P35.

RESULTS

Intrathecal clonidine produces age- and dose-dependent analgesia in rat pups. Maximal doses of clonidine did not alter the degree or distribution of apoptosis or increase glial reactivity in the neonatal spinal cord. No spinal histopathology was seen 1 or 7 days after injection at any age. Intrathecal clonidine did not produce persistent changes in reflex sensitivity to mechanical or thermal stimuli at P35.

CONCLUSIONS

Intrathecal clonidine in the postnatal rat did not produce signs of spinal cord toxicity, even at doses much larger than required for analgesia. The therapeutic ratio (maximum tolerated dose/antihyperalgesic dose) was >300 at P3, >30 at P7, and >10 at P21. These data provide additional information to inform the clinical choice of spinal analgesic drug in early life.

Validation of a preclinical spinal safety model: effects of intrathecal morphine in the neonatal rat

BACKGROUND

Preclinical studies demonstrate increased neuroapoptosis after general anesthesia in early life. Neuraxial techniques may minimize potential risks, but there has been no systematic evaluation of spinal analgesic safety in developmental models. We aimed to validate a preclinical model for evaluating dose-dependent efficacy, spinal cord toxicity, and long-term function after intrathecal morphine in the neonatal rat.

METHODS

Lumbar intrathecal injections were performed in anesthetized rats aged postnatal day (P) 3, 10, and 21. The relationship between injectate volume and segmental spread was assessed postmortem and by in vivo imaging. To determine the antinociceptive dose, mechanical withdrawal thresholds were measured at baseline and 30 min after intrathecal morphine. To evaluate toxicity, doses up to the maximum tolerated were administered, and spinal cord histopathology, apoptosis, and glial response were evaluated 1 and 7 days after P3 or P21 injection. Sensory thresholds and gait analysis were evaluated at P35.

RESULTS

Intrathecal injection can be reliably performed at all postnatal ages and injectate volume influences segmental spread. Intrathecal morphine produced spinally mediated analgesia at all ages with lower dose requirements in younger pups. High-dose intrathecal morphine did not produce signs of spinal cord toxicity or alter long-term function.

CONCLUSIONS

The therapeutic ratio for intrathecal morphine (toxic dose/antinociceptive dose) was at least 300 at P3 and at least 20 at P21 (latter doses limited by side effects). These data provide relative efficacy and safety for comparison with other analgesic preparations and contribute supporting evidence for the validity of this preclinical neonatal safety model.