Chart-documented onsite escalation-of-care during outpatient parenteral ketamine: A 15-year safety and risk management audit of 1985 IV/IM sessions in Japan

Abstract

Background

Off-label outpatient parenteral ketamine programs are expanding, yet rare perisession events requiring urgent escalation of care are difficult to quantify for local risk management. This documentation-based audit estimates denominator-based upper bounds for prespecified onsite escalation-of-care actions; it does not assess efficacy or long-term outcomes.

Methods

Retrospective chart audit of routine outpatient IV/IM ketamine sessions at two anesthesiology clinics in Japan (Nagoya: January 2010–June 2025; Tokyo: December 2024–June 2025). Adults (≥18 years) with ≥1 parenteral session were included. Two clinicians audited each session record for Tier 1 escalation-of-care events from initiation until discharge; session counts were reconciled with operational records. Exact one-sided 95% upper confidence bounds were calculated under zero events.

Results

Among 299 unique adults identified, 296 received ≥1 parenteral session (1985 sessions: IV 1779; IM 206). No Tier 1 events were chart-documented (0/1985), yielding a one-sided 95% upper confidence bound of 0.15% per session (IV 0.17%; IM 1.44%); the patient-level upper bound was 1.01% (0/296). A fall requiring ambulance transport was documented after formal discharge (outside the prespecified onsite perisession observation window).

Conclusions

Over a 15-year program horizon, no Tier 1 escalation-of-care events were chart-documented during the onsite perisession window. Findings provide documentation-based upper bounds for rare, high-acuity onsite events relevant to monitoring and rescue planning, but may underestimate reactions not prompting urgent intervention and harms after discharge.