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Effects on upper airway collapsibility of presence of a pharyngeal catheter
Author(s) -
Maddison Kathleen J.,
Shepherd Kelly L.,
Baker Vanessa A.,
Lawther Bradley,
Platt Peter,
Hillman David R.,
Eastwood Peter R.,
Walsh Jennifer H.
Publication year - 2015
Publication title -
journal of sleep research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.297
H-Index - 117
eISSN - 1365-2869
pISSN - 0962-1105
DOI - 10.1111/jsr.12193
Subject(s) - airway , medicine , obstructive sleep apnea , pharynx , anesthesia , polysomnography , catheter , continuous positive airway pressure , apnea , airway resistance , surgery
Summary Catheters that traverse the pharynx are often in place during clinical or research evaluations of upper airway function. The purpose of this study was to determine whether the presence of such catheters affects measures of upper airway collapsibility itself. To do so, pharyngeal critical closing pressure (Pcrit) and resistance upstream of the site of collapse Rus) were assessed in 24 propofol‐anaesthetized subjects (14 men) with and without a multi‐sensor oesophageal catheter (external diameter 2.7 mm) in place. Anaesthetic depth and posture were maintained constant throughout each study. Six subjects had polysomnography(PSG)‐defined obstructive sleep apnea (OSA) and 18 either did not have or were at low risk of OSA. Airway patency was maintained with positive airway pressure. At intervals, pressure was reduced by varying amounts to induce varying degrees of inspiratory flow limitation. The slope of the pressure flow relationship for flow‐limited breaths defined Rus. Pcrit was similar with the catheter in and out (−1.5 ± 5.4 cmH 2 O and −2.1 ± 5.6 cmH 2 O, respectively, P = 0.14, n = 24). This remained the case both for those with PSG‐defined OSA (3.9 ± 2.2 cmH 2 O and 2.6 ± 1.4 cmH 2 O, n = 6) and those at low risk/without OSA (−3.3 ± 4.9 cmH 2 O and ‐3.7 ± 5.6 cmH 2 O, respectively, n = 18). Rus was similar with the catheter in and out (20.0 ± 12.3 cmH 2 O mL −1 s −1 and 16.8 ± 10.1 cmH 2 O mL −1 s −1 , P = 0.22, n = 24). In conclusion, the presence of a small catheter traversing the pharynx had no significant effect on upper airway collapsibility in these anaesthestized subjects, providing reassurance that such measures can be made reliably in their presence.