Evaluation of sex-based differences in airway size and the physiological implications

Mann, Leah M.; Angus, Sarah A; Doherty, Connor J.; Dominelli, Paolo B.

doi:10.1007/s00421-021-04778-2

Cited by 10 publications

(3 citation statements)

References 70 publications

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“…In addition to pathologic differences in the luminal area of conducting airways, anatomic differences between males and females are well established in the literature 11 , 12 , 31 , 32 . Males have larger luminal areas than females in the central conducting airways; this difference in airway size may affect resistance to air flow and aerosol deposition across the lifespan 33 . Consistent with previous studies, males in our cohort had larger luminal areas than females in all seven of the central conducting airways that were measured.…”

Section: Discussionmentioning

confidence: 99%

Greater central airway luminal area in people with COVID-19: a case–control series

Jeltema

Gorman

Ovrom

et al. 2022

Sci Rep

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Respiratory epithelium in the conducting airways of the human body is one of the primary targets of SARS-CoV-2 infection, however, there is a paucity of studies describing the association between COVID-19 and physical characteristics of the conducting airways. To better understand the pathophysiology of COVID-19 on the size of larger conducting airways, we determined the luminal area of the central airways in patients with a history of COVID-19 compared to a height-matched cohort of controls using a case–control study design. Using three-dimensional reconstruction from low-dose high-resolution computed tomography, we retrospectively assessed airway luminal cross-sectional area in 114 patients with COVID-19 (66 females, 48 males) and 114 healthy, sex- and height-matched controls (66 females, 48 males). People with a history of smoking, cardiopulmonary disease, or a body mass index greater than 40 kg·m−2 were excluded. Luminal areas of seven conducting airways were analyzed, including trachea, left and right main bronchus, intermediate bronchus, left and right upper lobe, and left lower lobe. For the central conducting airways, luminal area was ~ 15% greater patients with COVID-19 compared to matched controls (p < 0.05). Among patients with COVID-19, there were generally no differences in the luminal areas of the conducting airways between hospitalized patients compared to patients who did not require COVID-19-related hospitalization. Our findings suggest that males and females with COVID-19 have pathologically larger conducting airway luminal areas than healthy, sex- and height-matched controls.

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Section: Discussionmentioning

confidence: 99%

Greater central airway luminal area in people with COVID-19: a case–control series

Jeltema

Gorman

Ovrom

et al. 2022

Sci Rep

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“…In our observations, female participants produced more ≥ 3 μm and ≥ 5 μm aerosol particles at 1 m in front of the singer than males. Although men have higher respiratory function parameters than women [ 21 ], women have a smaller airway cross-sectional area [ 22 ]. This smaller cross-sectional area has been shown in computed tomography studies to have a difference in the size of glottal folds.…”

Section: Discussionmentioning

confidence: 99%

Expansion of droplets during speaking and singing in Japanese

Kato

Okamoto²,

Miyoshi³

et al. 2022

PLoS ONE

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During the COVID-19 pandemic, a number of infection clusters associated with choral singing have been reported. Singing generates droplets and carries the risk of spreading infection. However, no reports have explored droplet flight and aerosol production rates by singing and speaking in Japanese. First, we conducted an observation experiment evaluating the maximum flight distance and number of droplets generated by singing in Japanese, using a high-speed camera and particle counter. Twenty amateur choir members, 10 male and 10 female (five members for each of the four voices), participated in the experiment. Subsequently, although the maximum distance that droplets traveled by singing in Japanese was 61 cm for men (median of 46.5, interquartile range, 36–57) and 56 cm for women (median of 27.5, interquartile range, 20–50), droplets were observed anteriorly and laterally to be up to 66.8 cm. At the singer’s mouth, ≥ 5 μm droplets were observed, whereas not observed at 1 meter toward the front of the singers in women and men, respectively. In German singing, droplets were observed up to 111 cm toward the front of the singer, possibly reflecting differences in pronunciation. In Japanese reading aloud, droplets were also observed up to 47 cm toward the front, whereas no droplet dispersion was observed by speaking the Japanese /a/ vowel or singing with wearing surgical mask toward the front. The aerosols produced when reading singing the /u/ vowels were significantly higher than those in other vowels. When singing in a choral group, keeping a sufficient distance at the front and side is recommended in minimizing infectious spread. If distance is not possible, practicing with /a/ vowels and avoiding consonants may be an alternative method. Our observations lasted only 50 seconds per song, and further observational studies are needed to determine the dynamics of aerosols that stay for long periods.

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“…First, there may be a biological sex difference in cardiac function with PAV breathing. Although comparing the sexes was not the purpose of the present study, females generally have smaller conducting airways compared to males (Mann et al, 2021;Sheel et al, 2016), potentially resulting in greater magnitude changes in ITP. Due to larger ITP swings, it is possible females may rely on respiration more for cardiac preload and SV compared to males.…”

Section: Perspectivesmentioning

confidence: 99%

Attenuating intrathoracic pressure swings decreases cardiac output at different intensities of exercise

Angus,

Taylor,

Mann

et al. 2023

The Journal of Physiology

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Intrathoracic pressure (ITP) swings that permit spontaneous ventilation have physiological implications for the heart. We sought to determine the effect of respiration on cardiac output () during semi‐supine cycle exercise using a proportional assist ventilator to minimize ITP changes and lower the work of breathing (Wb). Twenty‐four participants (12 females) completed three exercise trials at 30%, 60% and 80% peak power (Wmax) with unloaded (using a proportional assist ventilator, PAV) and spontaneous breathing. Intrathoracic and intraabdominal pressures were measured with balloon catheters placed in the oesophagus and stomach. Left ventricular (LV) volumes and were determined via echocardiography. Heart rate (HR) was measured with electrocardiogram and a customized metabolic cart measured oxygen uptake (). Oesophageal pressure swings decreased from spontaneous to PAV breathing by −2.8 ± 3.1, −4.9 ± 5.7 and −8.1 ± 7.7 cmH2O at 30%, 60% and 80% Wmax, respectively (P = 0.01). However, the decreases in Wb were similar across exercise intensities (27 ± 42 vs. 35 ± 24 vs. 41 ± 22%, respectively, P = 0.156). During PAV breathing compared to spontaneous breathing, decreased by −1.0 ± 1.3 vs. −1.4 ± 1.4 vs. −1.5 ± 1.9 l min−1 (all P < 0.05) and stroke volume decreased during PAV breathing by −11 ± 12 vs. −9 ± 10 vs. −7 ± 11 ml from spontaneous breathing at 30%, 60% and 80% Wmax, respectively (all P < 0.05). HR was lower during PAV breathing by −5 ± 4 beats min−1 at 80% Wmax (P < 0.0001). Oxygen uptake decreased by 100 ml min−1 during PAV breathing compared to spontaneous breathing at 80% Wmax (P < 0.0001). Overall, attenuating ITPs mitigated LV preload and ejection, thereby suggesting that the ITPs associated with spontaneous respiration impact cardiac function during exercise. imageKey points Pulmonary ventilation is accomplished by alterations in intrathoracic pressure (ITP), which have physiological implications on the heart and dynamically influence the loading parameters of the heart. Proportional assist ventilation was used to attenuate ITP changes and decrease the work of breathing during exercise to examine its effects on left ventricular (LV) function. Proportional assist ventilation with progressive exercise intensities (30%, 60% and 80% Wmax) led to reductions in cardiac output at all intensities, primarily through reductions in stroke volume. Decreases in LV end‐diastolic volume (30% and 60% Wmax) and increases in LV end‐systolic volume (80% Wmax) were responsible for the reduction in stroke volume. The relationship between cardiac output and oxygen uptake is disrupted during respiratory muscle unloading.

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Evaluation of sex-based differences in airway size and the physiological implications

Cited by 10 publications

References 70 publications

Greater central airway luminal area in people with COVID-19: a case–control series

Greater central airway luminal area in people with COVID-19: a case–control series

Expansion of droplets during speaking and singing in Japanese

Attenuating intrathoracic pressure swings decreases cardiac output at different intensities of exercise

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