Pretreatment with midazolam blunts the rise in intracranial pressure associated with ketamine sedation for lumbar puncture in children.

OBJECTIVE: Ketamine has a long history of use during pediatric procedural sedation. Concerns about raising intracranial pressure may limit use in certain situations. Whereas some data suggest that benzodiazepine coadministration may blunt this response, pediatric data during procedural sedation do not exist. We evaluated the effects of midazolam pretreatment on intracranial pressure during ketamine sedation in children.

DESIGN: Prospective, randomized clinical study.

SETTING: Outpatient Medical Observation unit at Kosair Children's Hospital.

PATIENTS: A total of 25 oncology patients in whom sedated lumbar puncture was scheduled.

INTERVENTIONS: Patients alternated between sedation in Group A (midazolam/ketamine prior to lumbar puncture) or Group B (ketamine only prior to lumbar puncture). Opening pressure, medication doses, sedation depth, and complications were recorded. A control group of non-ketamine-sedated patients (Group C) was added to differentiate drug vs. disease-specific opening pressure changes. Between-group differences were compared by linear mixed effects model or contingency table with p < 0.05 considered significant.

MEASUREMENTS AND MAIN RESULTS: Twenty-five patients aged 82 ± 49 months were sedated 84 times. Thirty-five sedations were in Group A, 39 in Group B, and 10 in Group C. Mean (95% confidence interval) adjusted opening pressure in Group A (22.0 [12.3, 22.2] cm H2O) was lower than Group B (26.5 [24.0, 29.2] cm H2O, p = 0.013). Opening pressure in Group C (17.3 [12.3, 22.2] cm H2O) was lower than in Group B (p = 0.002) but not in Group A (p = 0.096). Ketamine doses were similar between Groups A and B (1.4 ± 0.6 mg/kg vs. 1.4 ± 0.4 mg/kg, p = NS). Mean midazolam pretreatment dose was 0.09 ± 0.02 mg/kg and did not correlate with measured opening pressure. Four patients, all in Group B, experienced significant emergence reactions.

CONCLUSION: While pretreatment with midazolam is associated with a reduction in intracranial pressure compared with sedation with ketamine alone, ketamine-containing regimens are associated with higher opening pressures than non-ketamine-containing regimens.