None listed
Conditions
Brief summary
High flow nasal cannula (HFNC) has been shown to provide better oxygenation compared to the venturi face mask and low flow nasal cannula during intravenous sedation for both bronchoscopy and dental procedures . Though there are no major effects reported with this device, gastric distension is a theoretical possibility. Continuous high flow together with the ability to create low levels of positive airway pressure can potentiate gastric distension. When gastric distension occurs, it causes an increase in the secretion of gastric acid through vagal response. Hence, there is a potential for increased gastric volume and secretions, along with an elevated intraluminal pressure. This may increase the risk of pulmonary aspiration of gastric contents. Data is lacking as to quantify this issue in clinical practice. The aim of this study is to assess gastric insufflation and volume in healthy volunteers after application of HFNC. We hypothesise that the application of high flow nasal oxygen will not result in gastric distension. Measurements will be made of the incidence of gastric insufflation before and after the application of HFNC. When the participants are ready, a baseline ultrasound estimate of the stomach volume estimate is done. Thereafter, oxygen will be delivered through a high-flow nasal cannula. This will be accomplished using the Optiflow THRIVE device (Opti-Flow, Auckland, New Zealand). Flow rate through the cannula will be commenced at 30 L/min and fractional inspired oxygen concentration will be set at 100%. The flow will be gradually increased and maintained at 60-70L/min during the study. The flow rate could be decreased up to 30 L/min if higher flow rate is not tolerated. A set of ultrasound measurements looking for gastric distension and antral area will be made at 10 minutes intervals till 30 minutes of HFNC delivery. Measurements will be obtained between peristaltic contractions when the stomach is resting. A set of three measurements will be made for each outcome variable and the mean value would be recorded. The HFNC will be ceased at 30 minutes and the participants are allowed to rest for another 30 minutes. During this time, they are not allowed to eat or drink. Another set of scans and measurements will be obtained 30 minutes after ceasing HFNC.
Interventions
When the participants are ready, a baseline ultrasound estimate of the stomach volume estimate is done. Thereafter, oxygen will be delivered through a high-flow nasal cannula. This will be accomplished using the Optiflow THRIVE device (Opti-Flow, Auckland, New Zealand). Flow rate through the cannula will be commenced at 30 L/min and fractional inspired oxygen concentration will be set at 100%. The flow will be gradually increased and maintained at 60-70L/min during the study. The flow rate coul
When the participants are ready, a baseline ultrasound estimate of the stomach volume estimate is done. Thereafter, oxygen will be delivered through a high-flow nasal cannula. This will be accomplished using the Optiflow THRIVE device (Opti-Flow, Auckland, New Zealand). Flow rate through the cannula will be commenced at 30 L/min and fractional inspired oxygen concentration will be set at 100%. The flow will be gradually increased and maintained at 60-70L/min during the study. The flow rate could be decreased up to 30 L/min if higher flow rate is not tolerated. A set of ultrasound measurements looking for gastric distension and stomach volume will be made at 10 min intervals till 30 minutes of HFNC delivery. Measurements will be obtained between peristaltic contractions when the stomach is resting. A set of three measurements will be made for each outcome variable and the mean value would be recorded. The HFNC will be ceased at 30 minutes and the participants are allowed to rest for another 30 minutes. During this time, they are not allowed to eat or drink. Another set of scans and measurements of stomach volume and distension will be obtained 30 minutes after ceasing HFNC. Peripheral oxygen saturation (SPO2) will be monitored throughout the study. The intervention will be carried out by anaesthesiologists and it will be performed in the post anaesthesia care unit where appropriate facilities are available to conduct the study.
Sponsors
The Queen Elizabeth Hospital
Study design
Allocation
Non-randomised trial
Intervention model
Single group
Primary purpose
Treatment
Masking
Open (masking not used)
Eligibility
Sex/Gender
All
Age
18 Years to 70 Years
Healthy volunteers
Yes
Inclusion criteria
Healthy non-pregnant volunteers 18-70 yrs, both males and females No significant organ impairment No language barrier Fasted for 6 hours for solids and liquids. Sips of water allowed till 2 hours of the study enrolment
Exclusion criteria
History of severe gastro oesophageal reflux disease, hiatus hernia, previous gastro-oesophageal or duodenal surgery Those who are on medications affecting gastric motility History of nasal blockage or congestion Participants unable to consent Diabetes mellitus Morbid obesity >40 BMI
Outcome results
None listed