Utility of High Flow Nasal Cannula in CO Toxicity

Determination of Half-life of the Carboxyhemoglobin Level and Utility of High Flow Nasal Cannula in Carbon Monoxide Toxicity in the Emergency Department

determination of the half-life of COHb in CO-poisoned patients with high flow nasal oxygen therapy in the ED.

Carbon monoxide (CO) poisoning is common and potentially fatal environmental emergency which requires immediate attention. It is responsible for up to 40,000 emergency department (ED) visits and 5000 to 6000 deaths per year, making it one of the leading causes of poisoning death in the United States. The management options for CO poisoning are limited to high flow oxygen by face mask or hyperbaric oxygen treatment. While half-life of carboxyhemoglobin (COHb) in a patient treating with high flow oxygen via a nonbreathing face mask is 90 minutes, it becomes 30 minutes with hyperbaric oxygen treatment (HBO). The hypothesis of this study is using high flow nasal oxygen therapy in the CO poisoning may be more effective and safer treatment method comparing to standard oxygen therapy in the ED. Also, it may be a safe promising alternative of hyperbaric oxygen therapy. The aim of the study is to determine the half-life of COHb in CO-poisoned patients with high flow nasal oxygen therapy in the ED.

Fisher&Paykel AIRVO™ 2 High Flow Nasal Cannula Therapy will be implemented to CO-poisoned patients. Oxygen flow rate will be started 60 L/min and be decreased as the patient has requested.

A high flow nasal cannula will be implemented to the CO-poisoned patients. In the meantime, intravenous access and cardiac monitorization will have been establishing. When the high flow nasal cannula becomes ready, the first venous blood sample will be taken and the treatment will be started without any delay. The gas flow rate will be started at the rate of 30 liters per minute and will be increased to the max flow rate which patient can tolerate and FiO2 of 1.0. If the first COHb level is lesser than 10%, the patient will be excluded and will receive standard emergency care. The blood sample will be drawn from existing IV access every 10 minutes until the COHb levels become %50 or lesser of the initial level. Once the COHb level becomes 50% of initial measurement, following blood samples will be taken in every 30 minutes.

Half life of COHb levels (%) under the high flow nasal oxygen therapy. Elimination rate of COHb will be determined in every 10 minutes according to venous blood gas COHb level.

Mucosal dryness, epistaxis and burn in the nasal cavity will be evaluated as a adverse events of high flow nasal cannula.

Patient comfort will be assessed according to verbal numeric rating scale by asking to patient to say a number between 0 to 10 with 0 being "high flow nasal cannula can not be tolerated" and 10 being " the most comfortable breath ever".

Inclusion Criteria: The patients who are admitted to the emergency department with CO poisoning with a CoHB level of >10%. The patients who accept to participate in the study. Exclusion Criteria: The patients who are <18 years old. The patients who need mechanical ventilation The patients who are implemented oxygen more than 30 minutes before the ED admission The patients who will be transferred to the hyperbaric oxygen center before the CoHB levels are decreased to the half.