Efficacy of Premixed Nitrous Oxide and Oxygen in Elderly Patient With Out-of-hospital Severe Acute Pain (MEOPA-PA)

Efficacy of Premixed Nitrous Oxide and Oxygen in Elderly Patient With Out-of-hospital Severe Acute Pain

Efficacy of Premixed Nitrous Oxide and Oxygen in Elderly Patient With Out-of-hospital Severe Acute Pain: a Randomized Double-blind Study

Pain in the elderly is poorly evaluated and clearly under treated. Premixed nitrous oxide and oxygen is used in the emergency medical care of the trauma, burns, during transport of patient with pain. None randomized study has validated the use of premixed nitrous oxide and oxygen in the emergency department in the elderly. The aim of the study is to demonstrate the efficacy of premixed nitrous oxide and oxygen compared to medical air in elderly patient with out-of-hospital severe acute pain

The primary endpoint is the percentage of patients with pain relief (with a numerical rating scale of 3/10 or lower) 15 minutes after randomisation. Secondary endpoints are treatment safety and adverse events, time to analgesia and duration of analgesia. This study will expect 108 patients assigned in two parallel groups, defined by a randomization scheme. Four sites will participate to the research. Eligible patients with a numeric rating scale (NRS) score higher than 6/10 are randomly allocated to receive either MEOPA, or medical air. Neither the investigator nor the nurse knows the treatment. Pain score will be measured at baseline and every 5 minutes until pain relief will be obtained. The safety evaluation will include non invasive monitoring of blood pressure, heart rate, and oxygen saturation by pulse oximetry (SpO2) and adverse events collection.

The patient will be taken care by the physician SMUR or home emergency. Upon acceptance of participation in the study, the clock will be started at the time of the establishment of the face mask. Premixed 50% nitrous oxide and oxygen is administered for 30 minutes and an opioid titration is started 10 minutes after the introduction of gas, unless the patient expresses pain score EN <3/10.

The patient will be taken care by the physician SMUR or home emergency. Upon acceptance of participation in the study, the clock will be started at the time of the establishment of the face mask. The medical air is administered for 30 minutes and an opioid titration is started 10 minutes after the introduction of gas, unless the patient expresses pain score EN <3/10.

Premixed 50% nitrous oxide and oxygen is a gas in cylinder of 5 litres delivered by a face mask. The gases of the study are contained in anonymous bottles of the same capacity. Bottles will only be differentiated by a letter: A or B.

Medical air is a gas in cylinder of 5 litres delivered by a face mask. The gases of the study are contained in anonymous bottles of the same capacity. Bottles will only be differentiated by a letter: A or B

The primary endpoint is the percentage of patients with pain relief (with a numerical rating scale of 3/10 or lower)

Inclusion Criteria: Patients aged 65 years old and over Severe acute pain (NRS score greater than 6) Exclusion Criteria: Contraindication of premixed 50% nitrous oxide and oxygen

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