Advice

Clinical and technical evidence

Clinical and technical evidence

A literature search was carried out for this briefing in accordance with the interim process and methods statement. This briefing includes the most relevant or best available published evidence relating to the clinical effectiveness of the technology. Further information about how the evidence for this briefing was selected is available on request by contacting mibs@nice.org.uk.

Published evidence

Five studies are summarised in this briefing: 2 observational studies, 2 case reports and 1 case series. The 5 studies included 98 adult patients, 68 of whom used the SuperNO2VA device. All included studies were done in the USA. Clinically relevant outcomes reported include: oxygen saturation, procedural interruptions and length of post-anaesthesia care unit stay. Included studies used SuperNO2VA intraoperatively for patients having deep sedation, and during intubation and postoperatively in cases needing general anaesthesia. Table 3 summarises the clinical evidence as well as its strengths and limitations.

Overall assessment of the evidence

There is limited published evidence on SuperNO2VA. Only 1 of the included studies involved a comparator (conventional nasal cannula), making it difficult to draw conclusions about the efficacy of SuperNO2VA compared with standard therapy. Furthermore, only 35 out of a total of 98 patients in the included studies had a confirmed diagnosis of obstructive sleep apnoea, making it difficult to generalise all study findings to this patient population. Sample sizes are also small.

Evidence is limited to the USA and there is no UK-based study evaluating SuperNO2VA. There is also a lack of statistical analysis, with only Dimou et al. (2019) reporting p values. A comparative study of SuperNO2VA compared with standard NHS perioperative care would be useful, involving a larger patient population with diagnosed obstructive sleep apnoea, to better establish its efficacy.

Table 3 Summary of selected studies

Ghebremichael et al. (2017)

Study size, design and location

A pilot observational study involving 30 adult patients with ASA status I to III having elective surgery needing general anaesthesia and tracheal intubation.

Location: USA.

Intervention and comparator(s)

Intervention: SuperNO2VA (n=30).

Comparator: none.

Key outcomes

SuperNO2VA provided adequate oxygenation and successful ventilation in 29 out of 30 patients (97% success rate, 95% confidence interval 83 to 100). Out of these 29 patients, 6 patients needed a nasal airway adjuvant and 1 patient needed 2 staff to successfully ventilate with SuperNO2VA. The mean duration of laryngoscopy was 50.7±23.3 seconds. During this time, the average oxygen saturation was 99.6±0.8%. The average of the lowest values of oxygen saturation seen throughout the airway procedure was 98.1±7.0%. The average peak airway pressure for the 29 patients was 17.97±3.95 mmHg with mean tidal volume of 573.7±40.7 ml.

Strengths and limitations

A good range of outcomes are considered. This is a single-arm observational study involving a small number of patients and so is considered to be low-quality evidence. Only 7 patients had OSA so limited generalisability to this population. The study was done in the USA therefore is not generalisable to a UK NHS setting. The study was supported by the company, increasing the potential for bias. Only the adult large mask size was evaluated. Use of the SuperNO2VA device was stopped after successful intubation, so it is not possible to generalise results to the intraoperative or postoperative settings. Intubation was successful on the first attempt and within 2.5 minutes for all cases, so the results are not generalisable to prolonged or difficult intubation.

Dimou et al. (2019)

Study size, design and location

A prospective observational study involving 56 consecutive patients presenting for EGD before bariatric surgery between June 2016 and August 2017.

Location: USA.

Intervention and comparator(s)

Intervention: SuperNO2VA (n=26).

Comparator: conventional nasal cannula (n=30).

Key outcomes

There were fewer episodes of desaturation in the SuperNO2VA group compared with nasal cannula (11.5% compared with 46.7%, p=0.004). The median lowest oxygen saturation was higher in the SuperNO2VA group (100% compared with 90.5%, p<0.0001). There were no interruptions in the SuperNO2VA group for bag-valve-mask ventilation, compared with 3 cases in the nasal cannula group (0 compared with 3, p=0.24). There was no significant difference in mean postoperative oxygenation (97.4±1.9% compared with 98±1.9%, p=0.36), PACU stay (49.9±10.1 minutes compared with 61.7±30.5 minutes, p=0.35) or procedure length (9.2±4.8 minutes compared with 7.8±2.9 minutes, p=0.18) in SuperNO2VA compared with nasal cannula groups. There were no complications in SuperNO2VA group but 1 complication in the control group.

Strengths and limitations

Statistically significant differences in baseline characteristics between the 2 groups limit comparability. The sample size was small. Only 22 patients overall had OSA (14 in SuperNO2VA group) limiting generalisability of study findings specifically to this patient group. Patients were allocated to either group by the anaesthetist with no randomisation, which may have introduced bias. Oxygen was delivered at the discretion of the anaesthetic team for the nasal cannula group, compared with 10 litres/minute in the SuperNO2VA group, limiting comparability of findings.

Cataldo et al. (2019)

Study size, design and location

A case report involving a 46-year old patient with OSA having a cardiac ablation needing tracheal intubation.

Location: USA.

Intervention and comparator(s)

Intervention: SuperNO2VA (n=1).

Comparator: none.

Key outcomes

Oxygen saturation was kept at 100% during intubation while the SuperNO2VA device was in situ. Postoperatively in the PACU with SuperNO2VA connected to wall oxygen, oxygen saturations were 99%.

Strengths and limitations

Patient had OSA which helps generalisability in this patient population. Author is a medical director of Vyaire Medical. A case report is low-quality evidence, with sample size of 1 and no comparator group. There was no statistical analysis of the results and limited reported outcomes. Study done in the USA which limits generalisability to NHS.

Kozinn et al. (2018a)

Study size, design and location

A case report involving a 50-year old patient using SuperNO2VA having transoesophageal echocardiography and electrical cardioversion under deep sedation.

Location: USA.

Intervention and comparator(s)

SuperNO2VA (n=1).

Comparator: none.

Key outcomes

SuperNO2VA device attached to a hyperinflation bag, maintained oxygen saturation of 99%, after unsuccessful nasal cannula use with oxygen desaturation to 85%. SuperNO2VA maintained oxygenation during the 45-minute procedure. During a repeat procedure the next day, SuperNO2VA maintained oxygen saturation ≥96% without the need for manual airway support or manipulation.

Strengths and limitations

Patient had severe OSA so findings are generalisable to this patient population. A case report is low-quality evidence. No comparator so unable to compare with standard care. Study done in the USA so not generalisable to NHS.

Kozinn et al. (2018b)

Study size, design and location

A multicentre case series involving 10 patients having deep sedation procedures using the SuperNO2VA mask.

Location: USA.

Intervention and comparator(s)

Intervention: SuperNO2VA (n=10).

Comparator: none.

Key outcomes

Oxygen saturation was maintained at >97% (range 98% to 100%, average 99%) in all cases. There were no cases of hypoxaemia, procedural interruption or termination or tracheal intubation.

Strengths and limitations

All patients were high risk or diagnosed with OSA so are generalisable to this population. A range of procedures (1 TEE, 1 OGD, 1 SVT ablation, 2 AV fistula procedures). Good range of clinically relevant outcomes. Multicentre study is higher quality evidence. Similar baseline characteristics of patients, however no statistical analysis of results or p values reported. No comparator so unable to compare with standard care. Only assessed use of SuperNO2VA in deep sedation procedures. Authors are on the medical advisory board of the company. One of the patients included in the study is the same patient reported on in the other study Kozinn et al. (2018a).

Abbreviations: ASA, American Society of Anaesthesiologists; AV, arteriovenous; EGD, esophagogastroduodenoscopy; OGD, oesophagogastroduodenoscopy; OSA, obstructive sleep apnoea; PACU, post-anaesthesia care unit, SVT, supraventricular tachycardia; TEE, transoesophageal echocardiogram.

Recent and ongoing studies