High-Flow Nasal Cannula and Desaturation Episodes in the Morbidly Obese Patients

Use of High-Flow Nasal Cannula to Prevent Desaturation Episodes in the Morbidly Obese Patients Undergoing Colonoscopy:A Prospective Randomized Clinical Trial

It is standard practice in the United States and many parts of world to perform Gastrointestinal (GI) endoscopy with the patient under deep sedation. Obesity is accepted as a patient specific risk factor for hypoxic events during procedural sedation for GI endoscopic procedures. The Obese population has a higher prevalence of obstructive sleep apnea (OSA) which is characterized by repeated obstruction of the upper airway, and leads to apnea and desaturation. This prospective, randomized study was designed to compare the effectiveness of the high flow nasal cannula and the standard nasal cannula in morbidly obese (BMI > 40) patients receiving deep intravenous sedation during colonoscopies. This study will assess whether use of the high flow nasal cannula (HFNC) leads to less intraoperative desaturation events compared to the current standard of care.

Study Overview

• Status: Completed
• Conditions: Obesity; Sleep Apnea; Colonoscopy; High Flow Nasal Cannula; Desaturation of Blood
• Intervention / Treatment: Device: The Comfort Flo system; Device: The Salter nasal cannula

Detailed Description

The prevalence of morbid obesity is increasing worldwide. As the severity of obesity increases, the incidence of diagnosed obstructive sleep apnea also rises. Studies have shown an incidence of sleep apnea as high as 64% in patients with a body mass index (BMI) over 40 and 100% in patients with a BMI greater than 60. Patients with OSA have been shown to have significant desaturations under intravenous sedation due to airway narrowing and obstruction. Several studies have also shown that morbidly obese subjects, independent of a diagnosis of OSA, run a higher perioperative risk of adverse airway events, including hypoxia.

Many morbidly obese subjects present to our institution for GI procedures under deep sedation. Providing anesthesia for this patient population is challenging and requires careful titration of drugs and superb airway management skills. The current standard of care for oxygen delivery in this setting is a Salter nasal cannula. There are no prospective, randomized studies that compare the use of a high flow humidified nasal cannula system and standard nasal cannula in morbidly obese patients presenting for colonoscopy under anesthesia.

Humidified high flow nasal cannula (HFNC) oxygen therapy utilizes an air oxygen blend allowing from 21% to 100% FiO2 delivery and generates up to 60 L/min flow rates. The gas is heated (35 to 40 degree Celsius) and humidified through an active heated humidifier and delivered via a single limb heated inspiratory circuit (to avoid heat loss and condensation) to the subject through a large diameter nasal cannula. Theoretically, HFNC offers significant advantages in oxygenation and ventilation over conventional methods (9). Constant high flow oxygen delivery provides steady inspired oxygen fraction (FiO2) and decreases oxygen dilution. It also washes out physiologic dead space and generates positive end expiration pressure (PEEP) that augments ventilation. In the current narrative review, Sotello et al. summarized factors explained the improvement in respiratory parameters by using HFNC. (1) Washout of the nasopharyngeal dead space; (2) Reduction in inspiratory resistance associated with gas flow through the nasopharynx; (3) Improvement in respiratory mechanical parameters associated with gas temperature and state of humidification; (4) Reduction in metabolic work associated with gas conditioning; (5) Provision of mild distending pressure.

Some studies have demonstrated a positive effect of HFNC on the apnea-hypopnea index (AHI) showing that use of HFNC could decrease hypoxic episodes in subjects with repetitive upper airway obstruction such as obstructive sleep apnea. The STOP-BANG questionnaire (SB) has been used successfully to screen patients undergoing therapeutic endoscopic procedures at higher risk for sedation-related adverse events.

We are hypothesizing that the HFNC will help maintain a patent airway and improve gaseous exchange in the morbidly obese patients undergoing deep sedation for colonoscopies and will result in a significant decrease in intraoperative desaturation events, thus improving morbidity and overall safety for this subgroup.

• Study Type: Interventional
• Enrollment (Actual): 59
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Texas
    • Dallas, Texas, United States, 75390
      • Parkland Helath Hospital System
    • Dallas, Texas, United States, 75390
      • Parkland Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 16 years to 78 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Age between 18-80
• Subjects undergoing colonoscopies
• Morbidly obese BMI ≥ 40

Exclusion Criteria:

• Subjects deemed hemodynamically unstable by the anesthesia team
• Subjects who are an aspiration risk and will require endotracheal intubation.
• Pregnancy
• Subjects with an allergy to propofol
• Patients who are unable to tolerate the high flow nasal cannula secondary to discomfort
• Subjects unwilling to sign consent
• Chronic obstructive pulmonary disease
• Patients that received medications other than lidocaine and propofol

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: The high flow nasal cannula; The Comfort Flo system will be used for the high flow nasal cannula during colonoscopy	Device: The Comfort Flo system; The Comfort Flo system will be used for the high flow nasal cannula during procedural sedation; Other Names: High flow nasal cannula
Placebo Comparator: The standard nasal cannula; The Salter nasal cannula will be used during the colonoscopy	Device: The Salter nasal cannula; A Salter nasal cannula will be used at 4L/ minute during the procedural sedation.; Other Names: Standard nasal cannula

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
The Number of Desaturation Episodes	The number of desaturation episodes defined as blood oxygen saturation (SpO2) below 90% during the perioperative period during colonoscopy.	Perioperative period during colonoscopy

Collaborators and Investigators

• Sponsor: University of Texas Southwestern Medical Center
• Investigators: Study Director: Amanda Fox, MD, UT Southwestern Medical Center

Study record dates

Study Major Dates

• Study Start (Actual): May 10, 2017
• Primary Completion (Actual): August 28, 2017
• Study Completion (Actual): January 22, 2018

Study Registration Dates

• First Submitted: May 8, 2017
• First Submitted That Met QC Criteria: May 8, 2017
• First Posted (Actual): May 10, 2017

Study Record Updates

• Last Update Posted (Actual): November 19, 2018
• Last Update Submitted That Met QC Criteria: November 15, 2018
• Last Verified: November 1, 2018

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Nervous System Diseases; Respiratory Tract Diseases; Apnea; Respiration Disorders; Sleep Disorders, Intrinsic; Dyssomnias; Sleep Wake Disorders; Sleep Apnea Syndromes
• Other Study ID Numbers: STU 112016-058

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: No

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: Yes
• product manufactured in and exported from the U.S.: Yes