Experimental Studies of the Gas Exchange through the Ostium of the Maxillary Sinus

Abstract

Model experiments were performed in order to investigate the gas exchange in the maxillary sinus. The exponent Q2 in the equation illustrating the gas exchange through the maxillary ostium was analysed in relation to the volume of the maxillary sinus, the size of the ostium, the nasal ventilation, the nasal respiratory pressure and the respiratory work. The experiments showed that the gas exchange, expressed as the exponent Q2, is inversely proportional to the size of the maxillary sinus, and principally directly proportional to the cross-sectional area of the ostial canal. It is also principally directly proportional to the nasal ventilation and positively correlated to the nasal respiratory pressure but estimations of the effect of these two parameters are difficult to perform separately. The relation between antral gas exchange and respiratory work has been analysed more thoroughly and a linear correlation was obvious although not directly proportional, since the diffusion of gas through the ostium will occur also when the respiratory work is zero. The correlation between respiratory work and antral gas exchange is different for different sizes of the ostium. A formula for the antral gas exchange including the sinus volume, the size and length of the ostial canal, the respiratory work and the diffusion has been elaborated.

Assessment of nasal and sinus nitric oxide output using single-breath humming exhalations

“…This is also supported by the in vivo experiments, where the rapid decline in NO during humming indicated sinus emptying. Previous work has shown that the time needed to exchange all gas in the sinuses varies between y5 min up to 1 h [10,17], with much longer time needed in patients with sinus disorders [10]. The current results indicate that almost the entire sinus volume is exchanged in one single exhalation if the subject is humming.…”

“…Finally, the respiratory pressure in the paranasal sinuses is similar to that in the nose when the ostia are patent and amounts to y1 cmH 2 O [6]. Earlier studies have shown that ostium size is the most important factor determining sinus ventilation [6,7,10,17], which is also influenced by airflow rate, airway pressure and sinus volume. In the present study all these factors affected the increase in nasal NO during humming and, again, ostium size seemed to be the most important.…”

“…The model parameters were chosen because they resemble physiological values [6,7], although it is impossible to define a normal nasal cavity and paranasal sinus since the anatomical and physiological variations are almost unlimited. The normal volume of the maxillary sinus is considered to be y15 mL, ranging 2-30 mL [17], and the NO concentrations in the paranasal sinuses are variable, ranging 5-w20 ppm [5]. The normal diameter of the maxillary ostium is y2 mm but may vary between 0.5-5 mm [6].…”

Primary implant stability in augmented sinuslift-sites after completed bone regeneration: a randomized controlled clinical study comparing four subantrally inserted biomaterials

“…The human sinus undergoes a constant pressure-change in routine breathing activities at a frequency of 12–18 times/minute in grown-ups when breathing through the nose, which represents the natural breathing behavior, resulting in a constant pressure change in the maxillary sinus of 5–10 mbar2627 that might add to even significant higher pressure forces at sneezing28.…”

The paranasal sinuses as the nitric oxide depot

“…Также было показано, что только прооперированные околоносовые пазухи с увели-ченными соустьями могут поддерживать концентрацию NO в полости носа за счет возможной в таком случае диф-фузии. Таким образом, предположения R. Aust и B. Drettner [33] о высокой скорости газообмена между полостью носа и околоносовыми пазухами в норме оказались ложными, так как диаметр естественного соустья при отсутствии до-полнительного соустья делает невозможным как меха-низм диффузии, так и активное (при каждом вдохе и вы-дохе) прохождение смеси газов из пазухи в полость носа и обратно. Отсутствие газообмена между полостью носа и околоносовыми пазухами показано в целом ряде исследо-ваний и в настоящее время считается признанным евро-пейским обществом ринологов [11,19].…”