Related Experiment Video
Updated: Sep 4, 2026
Cone Beam Intraoperative Computed Tomography-based Image Guidance for Minimally Invasive Transforaminal Interbody Fusion
Published on: August 6, 2019
The Ability of Infrared Thermography to Detect Successful Caudal Block in Children Undergoing Infra-Umbilical Surgery
Mina Adolf Helmy1, Ingy Hamed Mohamed1, Maha Mostafa1
1Department of Anesthesia and Critical Care Medicine, Cairo University, Cairo, Egypt.
Insights
Infrared thermography accurately confirms caudal block success in pediatric surgery. A skin temperature increase of 1.2°C-1.4°C at the foot within 10 minutes indicates a successful block with 95% accuracy.
Area of Science:
- Pediatric Anesthesiology
- Pain Management
- Medical Imaging
Background:
- Caudal epidural blocks are common in pediatric surgery but can fail due to anatomical variations or operator inexperience.
- Early detection of block effectiveness is crucial for optimal pain management and improved patient outcomes.
Purpose of the Study:
- To evaluate the efficacy of infrared thermography in determining the success of caudal blocks in children.
- To establish reliable temperature change thresholds for confirming successful caudal blocks.
Main Methods:
- A prospective observational study involving 143 children (2-12 years) undergoing infra-umbilical surgery with caudal blocks.
- Infrared thermography (FLIR C2) measured skin temperature at the foot, toe, and suprapubic area pre-block and at 2, 5, 10, and 15 minutes post-block.
- Area Under the Curve (AUC) analysis assessed the ability of temperature change (Δ) at 10 minutes to predict block success.
Main Results:
- 20% of caudal blocks failed. Successful blocks showed significantly higher temperature increases compared to failed blocks at 10 and 15 minutes.
- At 10 minutes, AUC for successful block detection was highest at the dorsum of the foot (0.92) and little toe (0.87).
- A Δ temperature of 1.2°C (foot) and 1.4°C (toe) at 10 minutes predicted successful blocks with 95%-96% positive predictive value.
Conclusions:
- Infrared thermography is a reliable, non-invasive tool for confirming caudal block success in anesthetized children.
- A 1.2°C-1.4°C skin temperature increase at the foot/toe 10 minutes post-block accurately indicates success with high predictive value.
Background:
Caudal epidural block is commonly used in pediatric surgeries but may fail due to anatomical variations or operator experience. Early recognition of block effectiveness is useful for timely pain management, improving outcomes and analgesic strategies.
Aims:
This study aimed to assess the ability of infrared thermography to determine caudal block success in children.
Methods:
In this prospective observational study, children (2-12 years) undergoing infra-umbilical surgery received a caudal block after the induction of general anesthesia. FLIR C2 thermal camera was used to assess skin temperature at the dorsum of the foot, little toe, and suprapubic area at the baseline and 2, 5, 10, and 15 min after the block. Temperature change (Δ) was calculated as the difference from baseline. The primary outcome was the ability of Δ temperature at 10 min to detect a successful block, assessed via the area under the receiver operating characteristics curve (AUC).
Results:
Data from 143 patients were analyzed; 29/143 (20%) patients had failed block. In the successful block group, the temperature increased over time and was significantly higher than that of the failed block group at 10 and 15 min. At 10 min, the AUC (95% confidence interval) for detecting successful block was higher at the dorsum of the foot (0.92 [0.86-0.96]) and little toe (0.87 [0.81-0.92]) compared to the suprapubic area (0.74 [0.66-0.81]). The positive predictive value for Δ temperature at the dorsum of the foot and little toe for detecting successful block was 95%-96% with cut-offs of 1.2°C and 1.4°C, respectively.
Conclusion:
In anesthetized children undergoing infra-umbilical surgeries, infrared thermography can accurately confirm successful caudal block. Ten minutes after the block, an increase in the skin temperature by 1.2°C-1.4°C at the dorsum of the foot and little toe can confirm block success with 95%-96% accuracy.
