Fig. 2From: A fixed nitrous oxide/oxygen mixture as an analgesic for patients with postherpetic neuralgia: study protocol for a randomized controlled trialSPIRIT figure: schedule of enrolment, interventions, and assessments. PHN postherpetic neuralgia, T0 baseline, T1 5 min after starting the therapy, T2 15 min after starting the therapy, T3 5 min after finishing the therapyBack to article page