Effect of ketamine on transcranial Doppler Gosling pulsatility index in children undergoing procedural sedation: A pilot study

Christopher T Stem; Sriram Ramgopal; Robert W Hickey; Mioara D Manole; Jeffrey R Balzer

doi:10.1002/emp2.12760

Effect of ketamine on transcranial Doppler Gosling pulsatility index in children undergoing procedural sedation: A pilot study

J Am Coll Emerg Physicians Open. 2022 Jul 18;3(4):e12760. doi: 10.1002/emp2.12760. eCollection 2022 Aug.

Authors

Christopher T Stem^{1

2}, Sriram Ramgopal³, Robert W Hickey², Mioara D Manole², Jeffrey R Balzer⁴

Affiliations

¹ Division of Pediatric Emergency Medicine Department of Pediatrics Medical University of South Carolina Charleston South Carolina USA.
² Division of Emergency Medicine Department of Pediatrics UPMC Children's Hospital of Pittsburgh Pittsburgh Pennsylvania USA.
³ Division of Emergency Medicine Department of Pediatrics Ann & Robert H. Lurie Children's Hospital of Chicago Northwestern University Feinberg School of Medicine Chicago Illinois USA.
⁴ Department of Neurological Surgery University of Pittsburgh School of Medicine Pittsburgh Pennsylvania USA.

Abstract

Objectives: There has been controversy over whether ketamine affects intracranial pressure (ICP) in children. Transcranial Doppler ultrasound (TCD) is a validated technique used to assess ICP changes noninvasively. Gosling pulsatility index (PI) directly correlates with ICP changes. The objective of this study was to quantify PI changes as a surrogate marker for ICP changes in previously healthy children receiving intravenous ketamine for procedural sedation.

Methods: We performed a prospective, observational study of patients 5-18 years old who underwent sedation with intravenous ketamine as monotherapy. ICP changes were assessed by surrogate PI at baseline, immediately after ketamine administration, and every 5 minutes until completion of the procedure. The primary outcome measure was PI change after ketamine administration compared to baseline (denoted ΔPI).

Results: We enrolled 15 participants. Mean age was 9.9 ± 3.4 years. Most participants underwent sedation for fracture reduction (87%). Mean initial ketamine dose was 1.4 ± 0.3 mg/kg. PI decreased at all time points after ketamine administration. Mean ΔPI at sedation onset was -0.23 (95% confidence interval [CI] = -0.30 to -0.15), at 5 minutes was -0.23 (95% CI = -0.28 to -0.18), at 10 minutes was -0.14 (95% CI = -0.21 to -0.08), at 15 minutes was -0.18 (95% CI = -0.25 to -0.12), and at 20 minutes was -0.19 (95% CI = -0.26 to -0.12). Using a clinically relevant threshold of ΔPI set at +1 (+8 cm H₂O), no elevation in ICP, based on the PI surrogate marker, was demonstrated with 95% confidence at all time points after ketamine administration.

Conclusions: Ketamine did not significantly increase PI, which was used as a surrogate marker for ICP in this sample of previously healthy children. This pilot study demonstrates a model for evaluating ICP changes noninvasively in the emergency department.

Keywords: intracranial pressure; ketamine; pulsatility index; sedation; transcranial Doppler; ultrasound.