High-flow oxygen via oxygenating mouthguard in short upper gastrointestinal endoscopy: A randomised controlled trial

Table 1 Characteristics of the patient at baseline (n, %)

Characteristics		SNC (n = 154)	HFMG (n = 138)
Age (median, IQR)		64, 56 to 72	59, 48.5 to 69.5
Male		71, 46.1%	67, 48.6%
Weight, kg (mean, SD)		76.4, 13.6	76.1, 14.8
BMI, kg/m2 (mean, SD)		26.6, 4.1	26.4, 3.9
ASA classification, I/II/III		14/67/73, 9.1%/43.5%/47.4%	16/58/64, 11.6%/42.0%/46.4%
Mallampati class, I/II/III		54/70/30, 35.1%/45.4%/19.5%	48/70/20, 34.8%/50.7%/14.5%
Baseline oximetry, SpO2 (median, IQR)		97%, 95% to 99%	98%, 97% to 99%
Past medical history
	Current smoking history	14, 9.1%	14, 10.1%
	Obstructive sleep apnoea	8, 5.2%	6, 4.3%
	Hypertension	69, 44.8%	46, 33.3%
	Ischemic heart disease	19, 12.3%	9, 6.5%
	Diabetes mellitus	34, 22.1%	33, 23.9%
	Dyslipidemia	36, 23.4%	26, 18.8%
	Chronic obstructive pulmonary disease	8, 5.2%	11, 8%
	Asthma	9, 5.8%	11, 8%
	Cirrhosis	25, 16.2%	34, 24.6%
	Orthotopic liver transplantation	19, 12.3%	25, 18.1%

ASA: American Society of Anesthesiologists; BMI: Body mass index; HFMG: High-flow via oxygenating mouthguard; IQR: Interquartile range; SpO₂: Oxygen saturation; SD: Standard deviation; SNC: Standard nasal cannula.

Table 2 Anaesthetic care parameters (n, %)

Anaesthetic care		SNC (n = 154)	HFMG (n = 138)	P value
Duration of sedation, min (median, IQR)		12, 6.9 to 17.1	12, 6.5 to 17.5	0.421
Propofol dose, mg/kg/hr (median, IQR)		13.3, 8.5 to 18.1	14.1, 7.8 to 20.5	0.189
Opioids		89, 57.8%	73, 52.9%	0.631
	Fentanyl	52, 33.8%	40, 29.0%
	Alfentanil	37, 24.0%	33, 23.9%
Midazolam		26, 16.9%	23, 16.7%	0.961

HFMG: High-flow via oxygenating mouthguard; IQR: Interquartile range; SNC: Standard nasal cannula.

Table 3 Upper gastrointestinal endoscopy parameters (n, %)

Endoscopy parameters		SNC, (n = 154)	HFMG, (n = 138)	P value
Duration of procedure, min (median, IQR)		10, 5.5 to 14.5	10, 4.5 to 15.5	0.684
Types of procedure				0.175
	Diagnostic Procedure	87, 56.5%	67, 48.6%
	Therapeutic Procedure	67, 43.5%	71, 51.4%
Types of upper GI endoscopy				0.27
	Gastroscopy	106, 68.8%	96, 69.6%
	Duodenoscope	1, 0.6%	1, 0.7%
	ERCP	32, 20.8%	34, 24.6%
	EUS	12, 7.8%	3, 2.2%
	Gastroscopy + EUS	3, 1.9%	4, 2.9%

EUS: Endoscopic ultrasound; ERCP: Endoscopic retrograde cholangiopancreatography; HFMG: High-flow via oxygenating mouthguard; SNC: Standard nasal cannula.

Table 4 Primary and secondary end points for the intention-to-treat analysis end point (n, %)

End point		SNC (n = 154)	HFMG (n = 138)	P value
Primary endpoint
	SpO2 < 90% of any duration	34, 22.1%	6, 4.4%	< 0.001
Secondary endpoint
	Lowest SpO2 (median, IQR)	95%, 91% to 99%	98%, 96.5% to 99.5%	< 0.001
	Any episode of hypoxaemia	74, 48.1%	26, 18.8%	< 0.001
	SpO2 90%-94% of any duration	40, 26.0%	20, 14.5%	0.015
	SpO2 76%-89% of any duration	28, 18.2%	6, 4.3%	< 0.001
	SpO2 ≤ 75% of any duration	6, 3.9%	0, 0%	0.019
	Clinically significant episode of hypoxaemia1	32, 20.8%	1, 0.7%	< 0.001
	SpO2 < 85% of any duration	19, 12.3%	3, 2.2%	0.001

¹Clinically significant episode of hypoxemia is defined as a need to change in flow or method of oxygen delivery that the patient was originally randomised to.

HFMG: High-flow via oxygenating mouthguard; IQR: Interquartile range; SpO₂: Oxygen saturation; SNC: Standard nasal cannula.

Table 5 Patient-reported outcomes for the intention-to-treat analysis (n, %)

Patient-reported outcomes – Likert scale	SNC (n = 154)	HFMG (n = 138)	P value
(1 = Very uncomfortable or unbearable, 5 = Very comfortable or not at all)
Response rate	115, 74.7%	102, 73.9%	0.882
Comfort level ≤ 2	4, 3.5%	5, 4.9%	0.6
Abdominal pain ≤ 2	3, 2.6%	0, 0.0%	0.1
Bloating ≤ 2	1, 0.9%	1, 1.0%	0.932
Mouth dryness ≤ 2	2, 1.7%	1, 1.0%	0.633
Mouth pain ≤ 2	2, 1.7%	1, 1.0%	0.633
Headache ≤ 2	1, 0.9%	1, 1.0%	0.932

HFMG: High flow via oxygenating mouthguard; SNC: Standard nasal cannula.