Use of Optiflow THRIVE High-Flow Nasal Oxygen System versus a Non-rebreather Oxygen Delivery Device in Patients with Increased Risks of Airway Obstruction in Interventional Radiology Procedures: A Randomized Pilot Study

doi:10.21203/rs.3.rs-8165967/v1

Background

The room configuration in interventional radiology procedures hinders simultaneous access to the patient’s airway and anesthesia machines, and this issue may lead to suboptimal sedation levels in patients with increased risks of airway obstruction owing to patient safety concern. We conducted a randomized trial to evaluate the effectiveness of using a high-flow nasal oxygen (HFNO) device (F&P Optiflow™) versus a standard non-rebreather oxygen delivery device to reduce airway obstruction and improve patient outcomes during anesthesia among patients with increased risks of airway obstruction.

Methods

Patients at increased risks of airway obstruction were randomized to receive 100% oxygen at a rate of either 70 L/min (HFNO group) or 8 L/min (standard-of-care [SoC] group) along with a continuous intravenous propofol infusion to achieve unconsciousness. We evaluated the total length of desaturation episodes [ToLDE] defined as oxygen saturation [SpO₂] ≤92%, the number of desaturation episodes, and the time spent in the postanesthesia care unit (PACU). The level of sedation was assessed using the number of bispectral index (BIS) episodes (defined as episodes of BIS value ≥ 61), and patients’ PACU self-reported symptoms.

Results

The study included 101 patients, 50 in the HFNO group and 51 in the SoC group. The mean ToLDE time was 0.34 minutes (median, 0; range 0-6.5 minutes) in the HFNO group and 0.97 minutes (median, 0; range 0-19.8 minutes) in the SoC group (P = 0.158). The proportion of patients experiencing at least one desaturation episode was 14% in the HFNO group and 26% in the SoC group (P = 0.212). The median total number of BIS episodes was higher in the SoC group (4; range, 0–19) than the HFNO group (2; range, 0–15; P = 0.005). Median PACU stay was 20 minutes (range, 0–60) in the HFNO group and 26 minutes (range, 5–60) in the SOC group (P = 0.076). Six of 50 patients (12%) in the HFNO group and 8 of 51 (16%) in the SoC group reported PACU complaints and the complaints were less severe in the HFNO group.

Conclusions

HFNO was not superior to a standard non-rebreather oxygen delivery device in preventing hypoxic events among patients with increased risks of airway obstruction undergoing moderate to deep sedation. However, HFNO may reduce the need for airway interventions and improve the overall patient experience and thus warrants further investigation.

Trial registration:

ClinicalTrials.gov ID: NCT04171037; Date of original registration: November 19, 2019; This study was retrospectively registered. Study principal investigator: Gang Zheng; This manuscript adheres to the applicable Consolidated Standards of Reporting Trials (CONSORT) guidelines.

Positioning patients with increased risks of airway obstruction flat during an interventional radiology procedure, particularly when the patient is under moderate or deep sedation, increases the risk of airway obstruction. The typical room setup in these procedures hinders simultaneous access to the patient’s airway and the anesthesia machine, which can lead to suboptimal sedation levels in these people owing to airway safety concerns. These patients often report being awake and experiencing procedural pain.

Clinical reports have suggested that high-flow nasal oxygen (HFNO) prolongs safe apneic oxygenation time and reduces hypoxic events.^{(1, 2, 3)} This randomized pilot study evaluated the effectiveness of using a HFNO device (F&P Optiflow™) versus a standard non-rebreather oxygen delivery device to reduce airway obstruction and improve patient experience during anesthesia among patients with increased risks of airway obstruction. We hypothesized that using a HFNO in patients with increased risks of airway obstruction was superior to using a standard non-rebreather to delivery 100% oxygen in reducing airway-related adverse events.

Ethical Approvals

This study was approved by the Institutional Review Board at The University of Texas MD Anderson Cancer Center (IRB2019-0348) and was registered in ClinicalTrials.gov (NCT04171037) and in the Clinical Trials Reporting Program database (NCI-2019-07291). All patients provided informed consent. Led by principal investigator Gang Zheng and supported by Fisher & Paykel Healthcare, this study was a prospective randomized controlled pilot study. This manuscript adheres to the applicable Consolidated Standards of Reporting Trials (CONSORT) guidelines.

Study Overview

Patients were randomized in a 1:1 ratio by the Clinical Oncology Research System (MD Anderson copyright 2000–2007) to receive either HFNO or the standard of care (SoC). Random block sizes were used to ensure numerical balance between study arms. Patients in the HFNO group received 100% oxygen via an Optiflow system (AA030 Optiflow Trace, Fisher & Paykel Healthcare, New Zealand), and patients in the SoC group received 100% oxygen via a non-rebreather face mask (Vyaire Medical, USA). A focused airway history and bedside airway assessment were conducted and informed consent was obtained in the preoperative area.

During the procedure, all patients in both groups received a continuous intravenous propofol infusion. For patients in the HFNO group, the oxygen flow rate began at 50 L/min and was increased to 70 L/min after the initiation of a propofol infusion and was maintained at 70 L/min until the end of the procedure. For patients in the SoC group, the oxygen flow rate was maintained at 8 L/min throughout the entire procedure. Patients’ oxygen saturation (SpO₂) levels were monitored and manually recorded. The bispectral index (BIS) was used to monitor the level of sedation in both groups.

Postoperative assessments with a standard checklist were performed in the postanesthesia care unit (PACU) once patients were fully awake. Patients reported if they experienced any awareness during the procedure, sore jaw or tongue, dysphagia, or dysphonia. Self-reported symptoms in the PACU were recorded for up to 30 minutes after PACU admission, and the length of the PACU stay in minutes was recorded.

Study Endpoints

The primary endpoint was the total length (in minutes) of all desaturation episodes (ToLDE) that a patient experienced during a 60-minute observation window starting from the initiation of the propofol infusion. A desaturation episode was defined as a drop in SpO₂ to 92% or lower. Secondary endpoints were the number of desaturation episodes, the number of BIS episodes (defined as episodes of BIS value ≥ 61), PACU observation time, and PACU self-reported symptoms.

Sample Size Justification

With 50 patients per study arm, the precision for the bounds of a 2-sided 95% confidence interval (CI) for the ToLDE time would extend 0.39 minutes on each side of the observed mean, assuming a common standard deviation of 1.0 minute per group. If the ToLDE time showed a highly skewed distribution, the proportion of patients experiencing at least one desaturation episode would be estimated for each study arm. Assuming a 15% desaturation rate and n = 50 patients, the half-width of a 2-sided 95% CI would extend approximately 10 percentage points on each side of the expected proportion (nQuery Advisor, v. 7.0).

Patient Enrollment

A designated study faculty member reviewed all patients scheduled for total intravenous anesthesia procedures in the daily interventional radiology schedule between November of 2019 and July of 2023 at The University of Texas MD Anderson Cancer Center. Eligible candidates included individuals diagnosed with obstructive sleep apnea (OSA), whether they used a continuous positive airway pressure device at home. Additionally, patients with a body mass index of 32 kg/m² or greater and a neck circumference of 40 cm or larger were potentially eligible irrespective of their OSA status. We excluded individuals who were 18 years old or younger or who had severe organ/system decompensation rendering them unable to tolerate moderate sedation; current pulmonary disease requiring supplemental oxygen; significantly compromised airways due to aerodigestive oncology-related mass effects, making minimal sedation or awake airway intubation the preferred anesthetic option; or a baseline SpO₂ reading of 92% or lower.

Data Collection

We collected data on patient demographics, American Society of Anesthesiologists physical status, Mallampati score, instances and duration of oxygen desaturation, occurrences, and duration of BIS episodes, and PACU self-reported symptoms. Study personnel manually recorded the instances and duration of oxygen desaturation and BIS episodes. PACU self-reported symptoms were gathered for each patient either when they met institutional discharge criteria or within 30 minutes of their PACU admission.

Statistical Analyses

Descriptive statistics were used to summarize continuous outcomes and patient characteristics, and scatterplots were used to explore distributional characteristics and bivariate relationships, respectively. Interval estimates were computed for continuous variables, such as ToLDE time, for each study arm independently using a 2-sided 95% CI. Exploratory analyses between study arms were conducted using the Wilcoxon rank-sum test for continuous variables and Fisher’s exact test for categorical variables. Logistic regression was used to determine the association between study arm and the experience of at least one episode of desaturation while adjusting for covariates of interest. Analyses were performed using Stata v. 16 (StataCorp), and P values less than 0.05 were considered statistically significant.

Table 1. Patient Characteristics by Study Arm

Characteristic	HFNO (N = 50)	SoC (N = 51)	Total (N = 101)
Age, years
Mean (SD)	60.18 (11.96)	60.96 (11.97)	60.57 (11.91)
Median (IQR)	62 (50.75–70.00)	64 (54.00–68.00)	63 (51.50–69.00)
Range	34.00–83.00	31.00–82.00	31.00–83.00
BMI^a, kg/m²
Mean (SD)	37.02 (5.84)	39.46 (7.96)	38.26 (7.07)
Median (IQR)	35.99 (33.60–40.09)	38.08 (34.72–45.51)	37.33 (33.74–43.48)
Range	22.35–52.07	24.92–67.05	22.35–67.05
Height^a, cm
Mean (SD)	170.99 (11.45)	168.96 (9.76)	169.96 (10.62)
Median (IQR)	169 (163.00–179.35)	169 (162.00–176.00)	169 (162.70–176.38)
Range	147.00–192.00	145.00–188.00	145.00–192.00
Weight^b, kg
Mean (SD)	107.12 (22.81)	109.36 (21.6)	108.24 (22.12)
Median (IQR)	110.6 (95.50–117.20)	108.5 (95.50–120.10)	109.25 (95.50–118.50)
Range	36.40–162.00	62.40–159.90	36.40–162.00
Sex, n (%)
Female	22 (44)	23 (45)	45 (45)
Male	28 (56)	28 (55)	56 (55)
ASA status^c, n (%)
II	1 (2)	2 (4)	3 (3)
III	49 (98)	48 (96)	97 (97)
Mallampati score^c, n (%)
I	1 (2)	1 (2)	2 (2)
II	14 (28)	17 (34)	31 (31)
III	33 (66)	32 (64)	65 (65)
IV	2 (4)	0 (0)	2 (2)

Abbreviations: ASA, American Society of Anesthesiologists; BMI, body mass index; IQR, interquartile range; HFNO, high-flow nasal oxygen; SD, standard deviation; SoC, standard of care.

^a Missing data for 1 patient in the HFNO group.

^b Missing data for 3 patients in the HFNO group and 4 patients in the SoC group.

^c Missing data for 1 patient in the SoC group.

Patient Characteristics

A total of 114 patients were identified who were eligible, 6 patients declined the study, and 108 patients were randomized to the study arms. Of the patients who were randomized, 6 patients had screening failures prior to the procedure owing to a last-minute change of the procedure plan by the procedure physicians and one patient had no follow-up measurements due to the last-minute change of the anesthesia plan by the patient. Thus, 101 patients were deemed evaluable for the primary endpoint, with 50 patients in the HFNO group and 51 patients in the SoC group (Fig. 1). Patient characteristics are listed in Table 1, and airway focused information, etc., relevant comorbidities and bedside airway measurements, are listed in Table 2.

Table 2

Clinical Measurements and History of Comorbidities by Study Arm
	HFNO (N = 50)	SoC (N = 51)	P	Total (N = 101)
Clinical measurements
Neck circumference, cm
Mean (SD)	43.46 (5.39)	43.78 (4.5)		43.62 (4.94)
Median (IQR)	42 (39.88–46.25)	43.5 (40.00–47.00)	0.514^a	43 (40.00–47.00)
Range	35.00–58.00	35.00–56.00		35.00–58.00
Inter-incisor gap distance, cm
Mean (SD)	5.62 (1.24)	5.76 (1.32)		5.69 (1.28)
Median (IQR)	6 (4.88–6.50)	6 (4.50–7.00)	0.628^a	6 (4.50–6.50)
Range	3.20–10.00	3.50–9.00		3.20–10.00
Thyromental distance, cm
Mean (SD)	8.16 (1.88)	8.03 (1.9)		8.1 (1.88)
Median (IQR)	8 (7.00–9.62)	8 (6.50–9.00)	0.669^a	8 (7.00–9.00)
Range	4.00–12.00	5.00–14.00		4.00–14.00
Sternomental distance, cm
Mean (SD)	13.01 (2.32)	12.6 (1.91)		12.8 (2.12)
Median (IQR)	13 (11.38–14.50)	12 (11.00–14.00)	0.303^a	13 (11.00–14.00)
Range	7.00–18.00	9.00–18.00		7.00–18.00
Comorbidities
History of snoring, n (%)
No	21 (42)	16 (31)	0.306^b	37 (37)
Yes	29 (58)	35 (69)		64 (63)
History of DMV, n (%)
No	50 (100)	51 (100)	----^c	101 (100)
OSA, n (%)
No	22 (44)	18 (35)	0.419^b	40 (40)
Yes	28 (56)	33 (65)		61 (60)
BMI > 35 kg/m², n (%)
No	25 (50)	18 (35)	0.161^b	43 (43)
Yes	25 (50)	33 (65)		58 (57)
Anterior DMV, n (%)
No	50 (100)	51 (100)	----^c	101 (100)
Age > 55 years, n (%)
No	22 (44)	18 (35)	0.419^b	40 (40)
Yes	28 (56)	33 (64)		61 (60)
Edentulousness, n (%)
No	35 (70)	39 (76)	0.506^b	74 (73)
Yes	15 (30)	12 (24)		27 (27)
Abbreviations: BMI, body mass index; DMV, difficult mask ventilation; IQR, interquartile range; HFNO, high-flow nasal oxygen; OSA, obstructive sleep apnea; SD, standard deviation; SoC, standard of care.
^a Wilcoxon rank-sum test P value.
^b Fisher’s exact test P value.
^C No statistical comparison.

TOLDE and Number of Desaturation Episodes

The mean ToLDE time in the HFNO group was 0.34 minutes (median, 0 minutes; range, 0–6.5 minutes), and the mean ToLDE in the SoC group was 0.97 minutes (median, 0 minutes; range: 0–19.8 minutes; P = 0.158; Table 3). The distribution of ToLDE time was highly skewed because most patients (80%) failed to experience desaturation episodes.

Table 3

ToLDE time, Length of PACU Observation, and BIS Episodes by Study Arm
	HFNO (N = 50)	SoC (N = 51)	P	Total (N = 101)
ToLDE time, min
Mean (SD)	0.34 (1.16_	0.97 (3.25)		0.66 (2.46)
Median (IQR)	0 (0.00–0.00)	0 (0.00–0.02)	0.158^a	0 (0.00–0.00)
Range	0.00–6.50	0.00–19.78		0.00–19.78
Total SpO₂ ≤ 92% episodes
0	43 (86)	38 (75)	0.514^b	81 (80)
1	3 (6)	4 (8)		7 (7)
2	2 (4)	4 (8)		6 (6)
3 or more	2 (4)	5 (10)		7 (7)
Experienced at least 1 SpO₂ ≤92% episode, n (%)
No	43 (86)	38 (74)	0.212^b	81 (80)
Yes	7 (14)	13 (26)		20 (20)
Min SpO₂^c, %	n = 7	n = 13		N = 20
Mean (SD)	90 (2.83)	88.62 (3.91)		89.1 (3.55)
Median (IQR)	91 (87.00–92.00)	90 (84.00–92.00)	0.349^a	91 (85.50–92.00)
Range	85.00–92.00	81.00–92.00		81.00–92.00
Max SpO₂^c, %	n = 7	n = 13		N = 20
Mean (SD)	91.86 (0.38)	90.38 (2.93)		90.9 (2.45)
Median (IQR)	92 (92.00–92.00)	92 (90.00–92.00)	0.203^a	92 (91.00–92.00)
Range	91.00–92.00	84.00–92.00		84.00–92.00
Length of PACU observation^d, min
Mean (SD)	24.62 (17.87)	30.39 (16.25)		27.53 (17.23)
Median (IQR)	20 (12.25–39.00)	26 (18.00–44.00)	0.076^a	23 (14.00–41.00)
Range	0.00–60.00	5.00–60.00		0.00–60.00
Total BIS value ≥61 episodes
Mean (SD)	3 (3.1)	4.69 (3.75)		3.85 (3.53)
Median (IQR)	2 (1.00–4.25)	4 (2.00–6.00)	0.005^a	3 (1.00–5.00)
Range	0.00–15.00	0.00–19.00		0.00–19.00
Experienced at least one BIS≥61 episode, n (%)
No	10 (20)	5 (10)	0.172^b	15 (15)
Yes	40 (80)	46 (90)		86 (85)
Abbreviations: BIS, bispectral index; HFNO, high-flow nasal oxygen; IQR, interquartile range; Max, maximum; Min, minimum; PACU, post-anesthesia care unit; SD, standard deviation; SoC, standard of care; SpO₂, oxygen saturation; ToLDE, total length of desaturation episode.
^a Wilcoxon rank-sum test P value.
^b Fisher’s exact test P value.
^c Of patients who experienced a desaturation episode.
^d Missing data for 1 patient in the SoC group.

Of all 101 patients, 20 (20%) experienced at least one desaturation episode. In the HFNO group, 7 patients (14%; 95% CI, 6%–27%) experienced at least one desaturation episode, and in the SoC group, 13 patients (26%; 95% CI, 14%–40%) experienced at least one desaturation episode (P = 0.212). Among the 20 patients experiencing desaturation episodes, ToLDE time ranged from approximately 1 second to 19.8 minutes (Table 3). Among the patients who experienced desaturation episodes, the mean ToLDE time was similar in the HFNO group (2.44 minutes; 95% CI, 0.36–4.52 minutes) and in the SoC group (3.79 minutes; 95% CI, 0.35–7.23 minutes).

BIS Episodes and PACU Observation Time

The median total number of BIS episodes that a patient experienced was significantly higher for patients in the SoC group (4; range, 0–19) than for patients in the HFNO group (2; range, 0–15; P = 0.005; Table 3 and Fig. 2). The median length of PACU observation time was longer for patients in the SoC group (26 minutes; range, 5–60 minutes) than patients in the HFNO group (20 minutes; range, 0–60 minutes; P = 0.076; Fig. 3).

PACU Self-Reported Symptoms

Patients reported experiencing jaw pain, sore tongue, and dysphagia. In the SoC group, 8 complaints (16%) were reported: jaw pain (n = 2; severe), sore tongue (n = 2; moderate), and difficulty swallowing (n = 4; mild). In the HFNO group, 6 complaints (12%) were reported: sore tongue (n = 4; mild) and dysphagia (n = 2; mild); no jaw pain was reported in this group. The proportion of patients reporting complaints was not significantly different between study arms (HFNO, 12%, vs. SoC, 16%; P = 0.592). None of the patients in the study experienced dysphonia.

Association between Patient Comorbidities and Desaturation Episodes

Although the study arms were not significantly different with respect to OSA (HFNO, 56%, vs. SoC, 65%; P = 0.419) or obesity (HFNO 50% vs. SoC 65%; P = 0.161), both comorbidities were more prevalent in the SoC group. OSA, obesity, and other comorbidities and clinical characteristics are summarized in Table 2. Findings from univariable logistic regression to assess the independent associations between each comorbidity and desaturation episodes indicated that patients with obesity were 14% more likely to experience a desaturation episode (odds ratio [OR] = 1.14; 95% CI, 0.42–3.09; P = 0.795) but patients with OSA were 24% less likely to experience a desaturation episode (OR = 0.76; 95% CI, 0.28–2.04; P = 0.582). The multivariable model showed that using HFNO relative to SoC reduced the odds of desaturation by 54% (OR = 0.46; 95% CI, 0.16–1.30; P = 0.143) after adjusting for obesity (OR = 1.02; 95% CI, 0.37–2.84; P = 0.963) and OSA (OR = 0.70; 95% CI, 0.26–1.92; P = 0.490).

Although previous studies and meta-analyses indicated that HFNO significantly reduces the incidence and duration of hypoxic events in patients at risk of hypoxemia under deep sedation,^{(6, 7)} our study found that using a HFNO at the rate of 70 L/min of 100% oxygen in patients who were obese or had obstructive sleep apnea (OSA) was not superior to using a standard non-rebreather to deliver 100% oxygen at a rate of 8 L/min in reducing airway-related adverse events. Specifically, there were no significant differences in the ToLDE (P = 0.158) and the proportion of patients experiencing desaturation episodes (P = 0.212) between the HFNO and SoC groups during interventional radiology procedures. These findings do not support our study hypothesis.

A previous multicenter study of 379 participants found that HFNO significantly reduced the incidence of desaturation episodes (SpO₂ ≤ 92%) by 23.4% (P < 0.001) in patients undergoing deep sedation for gastrointestinal endoscopies.⁽⁷⁾ However, our study did not observe similar outcomes, which may be attributed to differences in patient populations. Our study focused on patients with increased risks of airway obstruction, whereas the previous study included patients with various systemic comorbidities related to respiration and circulation. In our study, the median body mass index was 37.33 kg/m² (IQR, 33.74–43.48 kg/m²), compared with 27 kg/m² (IQR, 23.9–30.5 kg/m²) in the previous study. Additionally, our patients underwent interventional radiology procedures in a flat position, in contrast to the 15- to 30-degree upper body elevation used during the gastrointestinal endoscopies in the previous study; the flat position likely exacerbated the risk of airway obstruction and respiratory complications. The combination of a flat position and sedation in obese patients not only increases the risk of upper airway obstruction and overall respiratory workload but also exacerbates the respiratory mechanism by reducing the functional residual capacity and increasing the closing capacity of the lungs.

When the mouth is closed, HFNO provides approximately 1 cm H₂O positive airway pressure per 10 L/min oxygen flow, reaching a maximum of 7 to 8 cm H₂O at 70 L/min,^(8,9) and is described as “dynamic, not set and not constant^”(10). However, maintaining a patent airway requires constant positive airway pressure above a critical level that varies between individuals.⁽¹¹⁾ In our study, 14% of patients in the HFNO group experienced desaturation episodes. This finding aligns with others from meta-analyses focused on obese patients,^{(12, 13, 14)} which suggests that although HFNO prolongs safe apnea, it does not significantly reduce hypoxic events. Another meta-analysis of 10 randomized controlled studies published between 2014 and 2021 (n = 564; body mass index, 33–52 kg/m²) demonstrated that use of HFNO prolonged safe apnea time but did not reduce hypoxic events.⁽¹³⁾ Further, Bright et al. conducted a meta-analysis and reported that use of a high-flow nasal cannula was not superior to use of a regular face mask in reducing hypoxic events (OR = 0.49; 95% CI, 0.15–1.63; P = 0.24).⁽¹⁴⁾

Although our findings did not support our hypothesis, we identified some benefits of using HFNO in interventional radiology procedures, suggesting that further investigation of HFNO is warranted. These benefits included fewer episodes of a BIS value of 61 or above (P = 0.005), shorter PACU stays (P = 0.07), and fewer and less severe PACU self-reported symptoms in the HFNO group compared with the SoC group. Frequent episodes of BIS value 61 or above during total intravenous anesthesia typically indicate inadequate sedation levels.

Study Limitations

This study has a few limitations. First, the electronic anesthesia record was incapable of capturing all the adverse events, the manual data collection in this study may have affected the preciseness of the data. Second, the study included both patients with obesities and patients with OSA. The underlying pathophysiologic and respiratory mechanisms of OSA and obesity are not the same, although airway obstruction is a primary feature in both conditions. For instance, the closing capacity and functional residual capacity are less affected in non-obese patients than in obese patients.

In this pilot study, HFNO did not demonstrate superior improvement to the use of a standard non-rebreather oxygen delivery device in preventing hypoxic events among patients with increased risks of airway obstruction during interventional radiology procedures. However, HFNO may reduce the need for airway intervention and shorten postoperative recovery time, enhancing the overall patient experience. The observed effects were nonsignificant and inconclusive; further investigation is needed to determine their clinical significance.

HFNO

high-flow nasal oxygen

PACU

postanesthesia care unit

OSA

obstructive sleep apnea

SoC

standard-of-care

ToLDE

total length of desaturation episodes

BIS

bispectral index

CONSORT

Consolidated Standards of Reporting Trials

OR

odds ratio

CI

confidence interval

SpO₂

peripheral oxygen saturation.

Ethics approval and consent to participate:This study was approved by the

Institutional Review Board at The University of Texas MD Anderson Cancer Center (IRB2019-0348) and was registered in ClinicalTrials.gov (NCT04171037) and in the Clinical Trials Reporting Program database (NCI-2019-07291).

All patients provided a signed informed consent.
Data Availability: Availability of data and materials are limited in the report and analysis.
Funding Statement: The University of Texas MD Anderson Cancer Center and the National Cancer Institute provided the primary sponsorship for this study. Fisher & Paykel Healthcare (New Zealand) provided funding support.
Conflicts of Interest: This study received funding support from Fisher & Paykel Healthcare (New Zealand).
Authors' contributions: 1. Gang Zheng, this author helped with the development of the study protocol, data verification, and writing manuscript. 2. Mike Hernandez, this author helped with the development of the study protocol, data analysis and writing manuscript. 3. Carin Hagberg, this author helped with the development of the study protocol, manuscript editing and finalization of the article.

Acknowledgements: The authors of this article would like to acknowledge the contributions of Ms. Raven Bailey, BS, Mr. Tyrone Burnett Jr., BS, and Mr. Tariq A. Syed, MS, who were the Senior Clinical Study Coordinators in the Division of Anesthesiology, Pain Management and Critical Care at The University of Texas MD Anderson Cancer Center, Houston, Texas, USA. Both Mr. Burnett and Mr. Syed helped with the protocol development and documentation, and Ms. Bailey helped with data collection and data organization. We thank Madison Semro, Associate Scientific Editor, and Stephanie Deming, Senior Scientific Editor, in the Research Medical Library at The University of Texas MD Anderson Cancer Center for editing this article. We also acknowledge the sponsorship of MD Anderson and the National Cancer Institute and the funding support of Fisher & Paykel Healthcare (New Zealand)

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Bright MR, Harley WA, Velli G, Zahir SF, Eley V. High-flow nasal cannula for apneic oxygenation in obese patients for elective surgery: a systematic review and meta-analysis. Anesth Analg. 2023;136(3):483–93.

Competing interest reported. The study received funding support from Fisher & Paykel Healthcare (New Zealand)

CONSORT2010Checklist.pdf

Use of Optiflow THRIVE High-Flow Nasal Oxygen System versus a Non-rebreather Oxygen Delivery Device in Patients with Increased Risks of Airway Obstruction in Interventional Radiology Procedures: A Randomized Pilot Study

Status:

Version 1

Abstract

Background

Methods

Results

Conclusions

Trial registration:

Figures

INTRODUCTION

METHODS

Ethical Approvals

Study Overview

Study Endpoints

Sample Size Justification

Patient Enrollment

Data Collection

Statistical Analyses

RESULTS

Patient Characteristics

TOLDE and Number of Desaturation Episodes

BIS Episodes and PACU Observation Time

PACU Self-Reported Symptoms

Association between Patient Comorbidities and Desaturation Episodes

DISCUSSION

Study Limitations

CONCLUSIONS

Abbreviations

Declarations

References

Additional Declarations

Supplementary Files

Status:

Version 1