Transnasal Humidified Rapid Insufflation Ventilatory Exchange With Nasopharyngeal Airway Facilitates Apneic Oxygenation: A Randomized Clinical Noninferiority Trial

Abstract

Background: Transnasal humidified rapid insufflation ventilatory exchange (THRIVE) was used to extend the safe apnea time. However, THRIVE is only effective in patients with airway opening. Nasopharyngeal airway (NPA) is a simple device that can help to keep airway opening. This study aimed to investigate the noninferiority of NPA to jaw thrust for airway opening during anesthesia-induced apnea. Methods: This was a prospective randomized single-blinded noninferiority clinical trial on the use of THRIVE in patients with anesthesia-induced apnea. The participants were randomly allocated to receive NPA or jaw thrust. The primary outcomes were PaO2 and PaCO2 at 20 min after apnea, with noninferiority margin criteria of -6.67 and 0.67 kPa, respectively. Results: A total of 123 patients completed the trial: 61 in the NPA group and 62 in the jaw thrust group. PaO2 at 20 min after apnea was 42.9 ± 14.0 kPa in the NPA group and 42.7 ± 13.6 kPa in the jaw thrust group. The difference between these two means was 0.25 kPa (95% CI, -3.87 to 4.37 kPa). Since the lower boundary of the 95% CI was > -6.67 kPa, noninferiority was established because higher PO2 is better. PaCO2 at 20 min after apnea was 10.74 ± 1.09 kPa in the NPA group and 10.54 ± 1.18 kPa in the jaw thrust group. The difference between the two means was 0.19 kPa (95% CI, -0.14 to 0.53 kPa). Since the upper boundary of the 95% CI was <0.67 kPa, noninferiority was established because lower PCO2 is better. No patient had a SpO2 < 90% during apnea. Conclusion: When THRIVE was applied during anesthesia-induced apnea, NPA placement kept airway opening and was noninferior to jaw thrust in terms of its effects on PaO2 and PaCO2 at 20 min after apnea. Clinical Trial Registration: ClinicalTrials.gov (NCT03741998).

Keywords: THRIVE; apneic oxygenation; arterial blood gas; general anesthesia; nasopharyngeal airway.

Conflict of interest statement

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Copyright © 2020 Chen, Yang, Tian, Zhang, Zhao, Huang, Tian, Zhang, Wu, Yu and Su.

Figures

Figure 1

The NPA group and jaw thrust group received OptiflowTM THRIVE system (Fisher & Paykel Healthcare, Auckland, New Zealand). (A) Humidifiers and heating system. (B) Flow meter. (C) Heated and humidified inspiratory circuit. (D) NPA. (E) Transnasal oxygen cannula. NPA, nasopharyngeal airway; THRIVE, transnasal humidified rapid insufflation ventilatory exchange.

Figure 2

The CONSORT flow diagram.

Figure 3

Nasopharyngeal airway facilitates transnasal humidified rapid insufflation ventilatory exchange and is noninferior to jaw thrust. (A) For PaO2, the difference value between the two groups was 0.25 kPa, and the 95% confidence interval was −3.87 to 4.37 kPa. Since the lower boundary of the confidence interval was > −6.67 kPa, noninferiority could be established because higher PO2 is better. (B) For PCO2, the difference value between the two groups was 0.19 kPa, and the 95% confidence interval was −0.14 to 0.53 kPa. Since the upper limit of the confidence interval was <0.67 kPa, noninferiority was established because lower PCO2 is better.

Figure 4

Arterial blood gases of the nasopharyngeal airway and jaw thrust groups during transnasal humidified rapid insufflation ventilatory exchange. There are no significant differences in PaO2(A), PaCO2(B), pH (C), standard base excess (D), and HCO3−(E) between the two groups. (F) For the nasopharyngeal airway group, the line represents linear regression with r = 0.8324 and p < 0.0001. The regression equation was Y = 2.123 *X + 40.30. For the jaw thrust group, the line represents linear regression with r = 0.7999 and p < 0.0001. The regression equation was Y = 2.054 *X + 40.68. MV, mechanical ventilation.

Figure 5

Vital signs of the nasopharyngeal airway (NPA) and jaw thrust groups during transnasal humidified rapid insufflation ventilatory exchange. (A) In all patients, the SpO2 at 20 min after apnea is >90%. (B,C) There are no significant differences between the two groups for the SpO2 and mean arterial pressure (MAP) at each time point. (D) At 20 min after apnea and 10 min after intubation, the heart rate (HR) is higher in the NPA group than in the jaw thrust group. There are no significant differences between the two groups at the other time points. MV, mechanical ventilation.