Anesth Pain Med.  2017 Apr;12(2):140-146. 10.17085/apm.2017.12.2.140.

Heart rate variability may be more useful than pulse transit time for confirming successful caudal block under general anesthesia in children

• Song IK
• Ji S
• Kim EH
• Lee JH
• Kim JT
• Kim HS

• KMID: 2379734
• DOI: http://doi.org/10.17085/apm.2017.12.2.140

Abstract

BACKGROUND
Confirming a successful caudal block is challenging in the pediatric population. Pulse transit time (PTT) may reflect the decrease in arterial resistance and may act as a potential indicator for confirming successful peripheral nerve or axial block. Heart rate variability (HRV) is also a possible candidate because it may be influenced by variation in sympathetic tone. We expected an increasing PTT pattern and change in HRV parameters after caudal block.
METHODS
We enrolled 27 male patients (range, 1-4 years old) who were scheduled for urological surgeries. Caudal block was performed with 1 ml/kg of 0.25% ropivacaine and 1 : 200,000 epinephrine under sevoflurane anesthesia after the surgery. Successful block was confirmed by auscultation and ultrasonography. PTT and HRV parameters, such as standard deviation of normal-to-normal intervals, root mean square of successive differences, very low-frequency power, low-frequency power (LF), high-frequency power (HF), LF/HF ratio, approximate entropy (ApEn) were calculated based on electrocardiography from 1 min before to 5 min after the block. Those variables were analyzed by repeated measures analysis of variance.
RESULTS
No significant change was found in PTT with time interval after caudal block. Heart rate and ApEn of the R-R interval decreased with time interval (P = 0.001, 0.033, respectively). Some HRV parameters showed notable changes, although statistically insignificant.
CONCLUSIONS
The PTT pattern may not be an indicator for successful caudal block. However, heart rate with parameters of HRV analysis may be alternatives.

Keyword

Caudal anesthesia; Heart rate

MeSH Terms

Anesthesia
Anesthesia, Caudal
Anesthesia, General*
Auscultation
Child*
Electrocardiography
Entropy
Epinephrine
Heart Rate*
Heart*
Humans
Male
Peripheral Nerves
Pulse Wave Analysis*
Ultrasonography
Epinephrine

Figure

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  Fig. 1 Change in approximate entropy (ApEn) of the R-R interval on the electrocardiogram from baseline to 5 min after the caudal block. Statistically significant change was present (P = 0.033).

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