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

NCT ID: NCT03148262

Last Updated: 2018-11-19

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 59 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2017-05-10
• Study Completion Date: 2018-01-22

Brief Summary

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.

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.

Conditions

Desaturation of Blood; Obesity; Colonoscopy; Sleep Apnea; High Flow Nasal Cannula

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: TREATMENT
• Blinding Strategy: NONE

Study Groups

The high flow nasal cannula

The Comfort Flo system will be used for the high flow nasal cannula during colonoscopy

Group Type: EXPERIMENTAL

The Comfort Flo system

Intervention Type: DEVICE

The Comfort Flo system will be used for the high flow nasal cannula during procedural sedation

The standard nasal cannula

The Salter nasal cannula will be used during the colonoscopy

Group Type: PLACEBO_COMPARATOR

The Salter nasal cannula

Intervention Type: DEVICE

A Salter nasal cannula will be used at 4L/ minute during the procedural sedation.

Interventions

The Comfort Flo system

The Comfort Flo system will be used for the high flow nasal cannula during procedural sedation

Intervention Type: DEVICE

The Salter nasal cannula

A Salter nasal cannula will be used at 4L/ minute during the procedural sedation.

Intervention Type: DEVICE

Other Intervention Names

High flow nasal cannula; Standard nasal cannula

Eligibility Criteria

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

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 80 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

University of Texas Southwestern Medical Center

OTHER

Sponsor Role: lead

Responsible Party

Christina Riccio

Assistant Professor

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

Amanda Fox, MD

Role: STUDY_DIRECTOR

UT Southwestern Medical Center

Locations

Parkland Helath Hospital System

Dallas, Texas, United States

Parkland Hospital

Dallas, Texas, United States

Countries

United States

Provided Documents

Document Type: Study Protocol and Statistical Analysis Plan

View Document

Other Identifiers

STU 112016-058

Identifier Type: -

Identifier Source: org_study_id