Obesity, Morbid
Conditions
Brief summary
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.
Detailed description
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.
Interventions
DEVICEOptiflow F&P 850™ System
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.
DEVICEfacemask
We will apply the facemask to the patient immediately upon entering the operating room to pre-oxygenate for five minutes.
DRUGRocuronium
Rocuronium will be administered after the ability to mask ventilate is determined.
DRUGPropofol
Propofol infusion 50 micrograms to 150 micrograms will be administered immediately on induction to maintain sedation throughout apneic oxygenation.
DRUGFentanyl
Fentanyl will be administered at the beginning of induction, 2 micrograms per kilogram.
DRUGMidazolam
midazolam will be given upon induction, 1-2 milligrams at the anesthesiologist's discretion.
DEVICEC-MAC Premium Video Intubation Platform-KARL STORZ
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).
Sponsors
The University of Texas Health Science Center, Houston
M.D. Anderson Cancer Center
Montefiore Medical Center
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
Yes
Inclusion criteria
* Adult patients (≥ 18 years old) undergoing elective surgery requiring general anesthesia * BMI \> 40 kg/m2 * American Society of Anesthesiology (ASA) Physical Status II-III
Exclusion criteria
* Chronic hypoxemia (SpO2 \<94% on room air or on home oxygen) * Acute respiratory failure * Coronary artery disease and/or congestive heart failure * Moderate-Severe pulmonary hypertension and/or RV dysfunction * Full stomach (recently eaten) * Pregnancy * Chronic pulmonary disease (specifically COPD or interstitial disease, NOT asthma) * Respiratory tract pathology * Facial Abnormality * American Society of Anesthesiology (ASA) Physical Status IV-V
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Time to desaturation | up to 10 minutes | 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. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Assess correlation between end tidal CO2 and transcutaneous CO2 monitoring | up to 10 minutes | Assessment of accurate correlation between transcutaneous CO2 monitoring, end tidal CO2, and/or PaCO2 will be performed up to 10 minutes. |
| Time until hypercarbia > 65 mmHg | up to 10 minutes | 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. |
Outcome results
None listed