Does Use of Ultrasound Reduce the Rate of Sham Caudal Block in Children

Caudal blocks are one of the most commonly performed regional anesthetics in children and are performed daily for a host of infra-umbilical surgical procedures. A caudal block is an epidural injection, most commonly of local anesthetic into the epidural space as accessed via the sacral hiatus. In children, the sacral hiatus is a normally occurring aperture in which the epidural space may be accessed with extremely minimal risk; as neural tissue ends more proximally. Due to this measure of safety, caudal blocks are preferred in children when compared with standard lumbar epidurals. Caudal blocks are performed blindly using palpation and tactile feedback to assess if the medication is being administered in the correct location. As a result of blind injection, administration of local anesthetic totally or partially outside of the correct site can often be unnoticed or identified after a significant volume has already been injected. With the potential for toxicity of local anesthetic, this may result in either the inability to give a complete dose or an unintentional and often unnoticed sham block "incorrect site of injection".

Study Overview

• Status: Withdrawn
• Conditions: Regional Anesthesia Morbidity
• Intervention / Treatment: Diagnostic test: Ultrasound guidance for caudal block

Detailed Description

Caudal blocks are one of the most commonly performed regional anesthetics in children and are performed daily for a host of infra-umbilical surgical procedures. A caudal block is an epidural injection, most commonly of local anesthetic into the epidural space as accessed via the sacral hiatus. In children, the sacral hiatus is a normally occurring aperture in which the epidural space may be accessed with extremely minimal risk; as neural tissue ends more proximally. Due to this measure of safety, caudal blocks are preferred in children when compared with standard lumbar epidurals. Caudal blocks are performed blindly using palpation and tactile feedback to assess if the medication is being administered in the correct location. As a result of blind injection, administration of local anesthetic totally or partially outside of the correct site can often be unnoticed or identified after a significant volume has already been injected. With the potential for toxicity of local anesthetic, this may result in either the inability to give a complete dose or an unintentional and often unnoticed sham block "incorrect site of injection".

Use of ultrasound has been proposed for identification of caudal block placement and correct medication spread. However, a recent review of the Pediatric Regional Anesthesia Network database reveals that ultrasound is reportedly only used in less that 3% of blocks. The benefit of ultrasound is safe and real-time confirmation of injection. Ultrasound allows the provider to determine with minimal local anesthetic or even saline injection if the correct space is accessed. Without ultrasound, failed blocks are either identified after significant percentage of the total dose of local anesthetic is incorrectly administered or intra or post operatively when the patient demonstrates a significant opioid requirement. This is problematic given that one of the primary benefits of a caudal block in children is the ability to avoid opioids.

Review of local practice here at Texas Children's Hospital for quality improvement purposes revealed a failure rate of caudal blocks to be 18%. Failure was defined as a heart rate increase with incision of >20% despite a caudal block and >1MAC of gas for the patient age. These patients all required opioids both intra and post operatively in addition to surgical levels of inhaled anesthetic agent.

• Study Type: Interventional
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Texas
    • Houston, Texas, United States, 77030
      • Texas Childrens Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: No older than 7 years (Child)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Children ages 0-84 months
• Infra-umbilical procedure for which a caudal block is already planned
• American Society of Anesthesiology classifications of 1,2 or 3

Exclusion Criteria:

• Incarcerated hernias
• Emergency procedures
• Local Anesthetic allergy
• Sacral dimple
• Rash over sacrum
• Parents/legal guardians unable to consent for surgical procedure in English language Foster Care/Child protective services as guardians
• Parental Refusal for caudal block or study participation
• American Society of Anesthesiology classifications other than 1,2 or 3

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: Ultrasound; The attending anesthesiologist will perform or instruct the placement of a caudal block according to their standard of practice. At the time of administration of local anesthetic into the caudal space, the study collaborator (SC) will ultrasound the caudal space keeping the provider placing the block blinded to the imaging. The provider placing the block will inject 0.5mL of saline. The provider will then be asked to state if they are correctly in the caudal space or not. If the provider feels they are not in the caudal space, they will re-do the procedure. If the provider fails to identify incorrect location and this is noted by ultrasound, the SC will inform the provider to re-do the procedure. All study participants will have ultrasound used for caudal block.

Diagnostic test: Ultrasound guidance for caudal block; The attending anesthesiologist will perform or instruct the placement of a caudal block according to their standard of practice. At the time of administration of local anesthetic into the caudal space, the study collaborator (SC) will ultrasound the caudal space keeping the provider placing the block blinded to the imaging. The provider placing the block will inject 0.5mL of preservative free saline. The provider will then be asked to state if they are correctly in the caudal space or not. If the provider feels they are not in the caudal space, they will re-do the procedure. If the provider fails to identify incorrect location and this is noted by ultrasound, the SC will inform the provider to re-do the procedure

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Identify the rate at which blindly placed caudal blocks are not within the epidural space	Assess the percentage of providers not recognizing wrong site of injection without ultrasound	15 minutes

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Identify the rate at which ultrasound can guide a wrong block into the correct location	Assess the number of blocks that are require the use of ultrasound to redirect needle into caudal space	15 minutes
Identify if lack of heart rate change on incision can predict successful placement when medication administration is successfully confirmed with ultrasound	With ultrasound identification of correct caudal injection, (successful block), does lack of heart rate change correlated with successful block	15 minutes
Identify if after using ultrasound to visualize placement, if concentrations of inhaled agents may be reduced in children	With demonstration of successful caudal injection, can inhaled agent concentration be reduced as calculated by MAC hours	30 minutes to 3 hours

Collaborators and Investigators

• Sponsor: Baylor College of Medicine
• Investigators: Principal Investigator: Adam C Adler, MD, FAAP, Texas Childrens Hospital

Study record dates

Study Major Dates

• Study Start (Actual): June 30, 2017
• Primary Completion (Actual): October 30, 2017
• Study Completion (Actual): October 30, 2017

Study Registration Dates

• First Submitted: September 12, 2017
• First Submitted That Met QC Criteria: September 13, 2017
• First Posted (Actual): September 14, 2017

Study Record Updates

• Last Update Posted (Actual): February 24, 2020
• Last Update Submitted That Met QC Criteria: February 20, 2020
• Last Verified: February 1, 2020

More Information

Terms related to this study

• Other Study ID Numbers: H-40844

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: Yes