Optiflow™ may provide an opportunity to prolong apnea time in the morbidly obese patient population. This study will examine whether Optiflow can do this, and compare the pre-oxygenation with Optiflow to the pre-oxygenation achieved with face mask.
The use of high flow nasal cannula (HFNC) originated in neonatal care, and has become widespread in its application for patients that are high risk for hypoxemia, both in critical care and emergency settings. Therefore, high flow nasal oxygenation continues to be studied in airway management for preoxygenation, as well as maintenance of oxygenation in airway procedures. Optiflow™, a humidified high flow nasal cannula, has already been shown to be useful in preventing desaturation during intubation in ICU patients versus the non-rebreathing mask, in addition to, prolonging safe apnea time in patients with potential difficult airways. Additionally, preoxygenation with HFNC prior to intubation of patients in hypoxemic respiratory failure has also been shown to decrease desaturation during apnea compared to preoxygenation with traditional bag valve mask. The morbidly obese patient presents a separate group of challenges to the anesthesiologist in regards to mask ventilation and intubation. Obesity (along with other factors) has been shown to contribute to difficulty with mask ventilation. Obese patients have altered respiratory physiology, including decreased functional residual capacity, increased oxygen consumption and lower tidal volumes, as compared to the non-obese patient. These factors contribute to obese patients potentially having a shorter apnea time before desaturating during induction of general anesthesia, as compared to the non-obese patient. Weight is inversely correlated with safe apnea time. Optiflow™ may provide an opportunity to prolong apnea time in the morbidly obese patient population. If demonstrated to be efficacious as a method for preoxygenation and prolongation of apneic time, this could provide a safer environment for intubation in this particular patient population.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Optiflow™ (Fisher \& Paykel Healthcare Limited, East Tamaki, Auckland-New Zealand) offers the ability to comfortably deliver a complete range of oxygen concentrations and flows to extend the traditional boundaries of oxygen therapy. This will be placed on the patient immediately upon entering the operating room for 5 minutes, at 50 liters per minute then increased to 70 liters per minute after induction.
We will apply the facemask to the patient immediately upon entering the operating room to pre-oxygenate for five minutes.
Rocuronium will be administered after the ability to mask ventilate is determined.
Time to desaturation
Intraoperatively, apneic time will be record from the time of administration of the muscle relaxant. The time until the first desaturation will be recorded. The maximum time of measurement will be 10 minutes.
Time frame: up to 10 minutes
Time until hypercarbia > 65 mmHg
The time until hypercarbia to more than 65 mmHg will be measured from the time of administration of the muscle relaxant. The time until transcutaneous CO2 is \> 65 mmHg will be recorded, unless 10 minutes is reached before that level is reached.
Time frame: up to 10 minutes
Assess correlation between end tidal CO2 and transcutaneous CO2 monitoring
Assessment of accurate correlation between transcutaneous CO2 monitoring, end tidal CO2, and/or PaCO2 will be performed up to 10 minutes.
Time frame: up to 10 minutes
This platform is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional.
Propofol infusion 50 micrograms to 150 micrograms will be administered immediately on induction to maintain sedation throughout apneic oxygenation.
Fentanyl will be administered at the beginning of induction, 2 micrograms per kilogram.
midazolam will be given upon induction, 1-2 milligrams at the anesthesiologist's discretion.
After patient is induced, the 5.5mm flexible intubation video scope (C-MAC Premium Video Intubation Platform-KARL STORZ) will then be introduced into the oropharynx and advanced into the trachea with the assistance of the C-MAC video laryngoscope (3 or 4 blade based on anesthesiologist's discretion).