Effects of combined oxygen and surgical masks on inspired fraction of oxygen: relevance to COVID-19-induced respiratory failure

Effect of pulmonary rehabilitation on functional status dyspnea and quality of life among post COVID-19 patients

OBJECTIVES

To determine the Effect of pulmonary rehabilitation on functional status dyspnea and quality of life among post-COVID-19 patients.

METHODS

The study utilized an experimental study design with a total of 120 participants to examine the effects of pulmonary rehabilitation. The participants were divided into two groups: Group A (experimental group) and Group B (control group). Demographic variables such as age, weight, and height were collected. Health-related quality of life (HRQL), post-COVID-19 functional status, and perceived exertion were assessed before and after the intervention.

RESULTS

Group A demonstrated a higher mean age than Group B, indicating a significant age difference between the two groups, with no significant difference observed in weight and height. Following the intervention, Group A exhibited significant improvement in HRQL, post-COVID-19 functional status, and perceived exertion compared to Group B.

CONCLUSION

Pulmonary rehabilitation had positive effects on health-related quality of life, post-COVID-19 functional status, and perceived exertion. The experimental group benefited from improved HRQL, suggesting an overall enhancement in their well-being. The study provides preliminary evidence supporting the effectiveness of pulmonary rehabilitation as an intervention for improving outcomes in individuals post-COVID-19.

Impact of surgical masks on fraction of inspired oxygen during oxygen therapy depends on the type of oxygen masks and respiratory conditions: volunteer- and simulation-based studies

Purpose

We investigated the impact of surgical masks (SM) during oxygen therapy using oxygen masks in volunteer- and simulation-based studies.

Methods

Fifteen volunteers wore the Hudson RCI^® or Open-Face Mask^® with/without an SM. The fraction of inspired oxygen concentration (FIO₂), end-tidal CO₂ (EtCO₂), partial pressure of inspired CO₂ (PICO₂), and respiratory rate (RR) were measured. The oxygen flow rate increased from 0 to 10 L/min. In the simulation-based study, FIO₂ was measured using a simulator that reproduced spontaneous breathing. RR was 12 or 24 bpm, and the tidal volume (Tv) was 300, 500, or 700 mL. The effect of oxygen mask fitting conditions was also examined. The primary outcome measure was FIO₂ at 6 L/min.

Results

In the volunteer-based study, FIO₂ was reduced when the SM was used with the Hudson RCI^® or Open-Face Mask^®. The FIO₂ drop was larger with the Open-Face Mask^® than with the Hudson RCI^®. The RR, EtCO₂, and PICO₂ significantly changed with the SM, but the differences were not clinically meaningful. In the simulation-based study, the SM with the Hudson RCI^® did not reduce FIO₂, but the SM with the Open-Face Mask^® significantly decreased FIO₂ under several conditions. However, the SM with the Hudson Mask^® reduced FIO₂ when the fit of the mask was inadequate. With the Open-Face Mask^®, lower RR and Tv resulted in larger differences in FIO₂.

Conclusions

The SM decreased FIO₂ during oxygen therapy with oxygen masks. The impact of SM depended on the type of the oxygen mask, mask fitting, and respiratory condition.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00540-022-03083-2.

Effects of wearing surgical masks on fraction of inspired oxygen in spontaneously breathing patients: improving safety for frontline healthcare professionals under pandemic situations

BACKGROUND

During pandemic situations, many guidelines recommend that surgical masks be worn by both healthcare professionals and infected patients in healthcare settings. The purpose of this study was to clarify the levels and changes of oxygen concentration over time while oxygen was administered over a surgical mask.

METHODS

Patients scheduled to undergo general anesthesia (n = 99) were enrolled in this study. First, patients were administered oxygen at 6 L/min via an oxygen mask over a surgical mask for 5 min. The patients removed the surgical mask and then took a 3-min break; thereafter, the same amount of oxygen was administered for another 5 min via the oxygen mask. We measured the fraction of inspired oxygen (FiO₂), the end-tidal CO₂ (EtCO₂), and respiratory frequency every minute for 5 min, both while administering oxygen with and without a surgical mask. The FiO₂ was measured at the beginning of inspiration and the EtCO₂ was measured at the end of expiration.

RESULTS

The FiO₂ at 5 min was significantly lower when breathing with a surgical mask than that without it (mean difference: 0.08 [95% CI: 0.067-0.10]; p <  0.001). In contrast, the EtCO₂ at 5 min was significantly higher when breathing with a surgical mask than that without it (mean difference: 11.9 mmHg [95% CI: 10.9-12.9]; p <  0.001).

CONCLUSION

The FiO₂ was lower when oxygen was administered over surgical masks than when patients did not wear surgical masks. Oxygen flow may need to be adjusted in moderately ill patients requiring oxygen administration.

Reduced Effective Oxygen Delivery and Ventilation with a Surgical Facemask Placed under Compared to over an Oxygen Mask: A Comparative Study

Objectives. Consensus guidelines for perioperative anesthesia management during the COVID-19 pandemic recommend that patients wear a facemask in addition to their oxygen mask or nasal cannulae following tracheal extubation, where this is practical. The effects on effective oxygen delivery and ventilation of a surgical facemask under compared to over an oxygen (O2) mask are unclear. Design. Single-center, comparative pilot study. Setting. Endoscopy procedure room at a major academic hospital. Subjects. Five healthy anesthesiologists. Interventions. Using a carbon dioxide (CO2) sampling line positioned at the lips, the fraction of inspired O2 (FiO2), fraction of expiratory O2 (FeO2), expiratory end-tidal CO2 (EtCO2), and respiratory rate (RR) were measured under the following conditions: (1) a surgical facemask only, (2) a surgical facemask under an O2 mask, (3) an O2 mask only, and (4) a surgical facemask over an O2 mask. Measurements and Main Results. The sampled fractional expired oxygen (FeO2) at the lips was significantly lower when the surgical facemask was under compared to when over the O2 mask (27.9± 1.68 vs. 49.9 ± 6.27, $p=0.001$ ), while there was no significant difference in inspired oxygen (FiO2). The sampled expiratory EtCO2 was significantly higher when the surgical facemask was under the O2 mask compared to when over the O2 mask (28.3 ± 8.5 vs. 23.5 ± 7.6, $p=0.026$ ). The RR was not significantly different when the surgical facemask was under compared to over the O2 mask. Conclusions. Effective oxygen delivery and ventilation was reduced (lower FeO2 and increased EtCO2) when a surgical facemask was placed under compared to over an O2 mask.

Oxygen Administration under Surgical Face Mask in COVID-19 Patients: A Game Changer

COVID-19 is a multifaceted infectious disease. The development of hypoxemic respiratory failure is not uncommon during the course of illness in some of them. The objectives of the present study were to assess the effect of the addition of a surgical face mask while delivering oxygen via nasal cannula in hypoxemic COVID-19 patients and highlight on the advantages and patient's comforts. We prospectively assessed 30 consecutive conscious and hypoxemic COVID-19 patients, requiring oxygen via nasal cannula. The mean PaO₂ without and with surgical face mask were 52 (+9) and 83 (−12) mm Hg respectively in the cohort, and the elevation in oxygen saturation was statistically significant (p <0.001). The present results encourage the delivery of oxygen under the surgical face mask in symptomatic COVID-19 patients, as it improves oxygen saturation and prevents aerosol dispersion with no change in PaCO₂. The other advantages of this method are a reduction in the total requirement of oxygen per patient, better utilization of scarce resources, and lessening of the expenses incurred for oxygen.

Investigation of the optimal method of oxygen administration with simultaneous use of a surgical mask: a randomized control study

Purpose

From the perspective of infection prevention during the Coronavirus disease 2019 (COVID-19) pandemic, a recommendation was made to use surgical masks after extubation in patients in the operating room. For compliance with this recommendation, anesthesiologists need to administer oxygen to the patient with an oxygen mask over the surgical mask. However, no studies have investigated whether this method allows good maintenance of oxygenation in patients. This study aimed to investigate which method of oxygen administration lends itself best to use with a surgical mask in terms of oxygenation.

Method

We administered oxygen to the study subjects using all the following three methods in random order: an oxygen mask over or under a surgical mask and a nasal cannula under the surgical mask. Oxygenation was assessed using the oxygen reserve index (ORi) and end-tidal oxygen concentration (EtO₂).

Result

This study included 24 healthy volunteers. ORi values with administration of oxygen were higher in the order of a nasal cannula under the surgical mask, an oxygen mask under the surgical mask, and an oxygen mask over the surgical mask, with median values of 0.50, 0.48, and 0.43, respectively, and statistically significant differences between all groups (P < 0.001). EtO₂ values were in the same order as ORi, with median values of 33.0%, 31.0%, and 25%, respectively, and statistically significant differences between all groups (P < 0.001).

Conclusion

Wearing a surgical mask over the nasal cannula during oxygen administration is beneficial for oxygenation and might help prevent aerosol dispersal.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00540-021-02998-6.