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Effect of caudal block injection speed on optic nerve sheath diameter in pediatric surgeries: A prospective
Açelya Toprak Karaoğlu1, Rasim Onur Karaoğlu2, Volkan Özen3
1Department of Anesthesiology and Reanimation, SBU Zeynep Kamil Training and Research Hospital, Istanbul, Türkiye.
Insights
Faster caudal block injections in children temporarily increase intracranial pressure and affect hemodynamics more than slower injections. Slower injection speeds during caudal blocks lead to more gradual physiological responses in pediatric patients.
Area of Science:
- Pediatric Anesthesiology
- Regional Anesthesia
- Pain Management
Background:
- Perioperative pain management in children is complex.
- Caudal block (CB) is common for pediatric lower abdominal/urogenital surgery.
- Impact of CB injection speed on patient physiology is not well understood.
Purpose of the Study:
- To investigate the effect of caudal block injection speed on intracranial and hemodynamic responses in pediatric patients.
- To compare optic nerve sheath diameter (ONSD) changes between fast and slow injection groups.
- To evaluate heart rate and mean arterial pressure variations based on injection speed.
Main Methods:
- Prospective observational cohort study of 64 pediatric patients (1-7 years).
- Patients received caudal block with 0.125% bupivacaine (0.8 mL/kg).
- Patients categorized by injection speed: 0.25 mL/s (slow) vs. 0.5 mL/s (fast).
Main Results:
- ONSD increased transiently post-caudal injection in both groups.
- Fast injection group showed a significantly greater immediate ONSD increase.
- Heart rate and mean arterial pressure showed mild, transient reductions, more pronounced in the fast group.
Conclusions:
- Caudal injection speed influences transient intracranial and hemodynamic changes in children.
- Slower injection speeds are associated with more gradual physiological responses.
- These effects are temporary, with ONSD returning to baseline within 20 minutes.
Abstract:
Perioperative pain management in children is challenging due to limited communication and the risk of long-term psychological effects. Regional anesthesia, particularly the caudal block (CB), is frequently used in pediatric surgery for lower abdominal and urogenital procedures. However, the influence of injection speed during CB on intracranial and hemodynamic responses remains unclear. This prospective observational cohort study included 64 pediatric patients (American Society of Anesthesiologists I-II, aged 1-7 years) undergoing elective lower abdominal or urogenital surgery under general anesthesia. All patients received a CB with 0.8 mL/kg of 0.125% bupivacaine. Injection speed was not assigned by the study protocol but reflected routine clinical practice, and patients were categorized according to the injection speed used (0.25 mL/s or 0.5 mL/s). The primary outcome was the change in optic nerve sheath diameter (ONSD) over time and between injection-speed groups. Secondary outcomes included heart rate and mean arterial pressure, recorded at baseline and at predefined time points after the block. Baseline ONSD values were similar between groups. ONSD increased transiently after caudal injection in both groups, with a significantly greater increase in the fast-injection group immediately after the block. These differences were short-lived, and ONSD values returned toward baseline within 10 to 20 minutes, with no persistent intergroup differences. Heart rate and mean arterial pressure showed mild, transient reductions in both groups, which were slightly more pronounced in the fast-injection group but remained within physiological limits. Different caudal injection speeds were associated with distinct transient changes in ONSD and hemodynamic parameters. Slower injection was associated with more gradual physiological responses during the early postinjection period.
