Nocturnal hypoventilation in neuromuscular disease: prevalence according to different definitions issued from the literature.
OBJECTIVE
Restrictive respiratory failure is a major cause of morbidity and mortality in neuromuscular diseases (NMD). Home mechanical ventilation (HMV) is used to treat hypoventilation, identified by daytime hypercapnia or nocturnal desaturation. Recently, transcutaneous measure of CO2 (TcCO2) has been increasingly used to detect hypoventilation, using different cut-offs. We aimed to compare the prevalence of hypoventilation in an unselected adult NMD population according to different definitions issued from the literature.


METHODS
All consecutive nocturnal capno-oximetries performed between 2010 and 2014 in unventilated adult NMD patients were analysed retrospectively. Concomitant blood gas analysis and lung function data were collected. Patients on oxygen therapy were excluded. Hypoventilation was defined according to eight criteria, based on daytime PaCO2, daytime base excess, nocturnal SpO2 or TcCO2.


RESULTS
Data from 232 patients were analysed (mean age 43.1 ± 15.4 years; 50.0 % women; vital capacity 59.2 ± 24.2 % of predicted). The hypoventilation prevalence was 10.3 to 61.2 %, depending on the used definition. The different definitions showed 49.1 to 94.8 % concordance (Cohen's kappa for agreement 0.115 to 0.763). Overall agreement between the eight definitions was poor (Light's kappa 0.267), and agreement between definitions based on nocturnal SpO2 and those based on TcCO2 was even lower (Light's kappa 0.204).


CONCLUSIONS
We found large differences in hypoventilation prevalence according to the used definition. This has practical consequences, as HMV indication relies upon hypoventilation detection. We believe that capno-oximetry should be included in the diagnostic tools used to detect hypoventilation but this requires an update of consensus guidelines to agree upon the best definition.
Service de Réanimation médicale et unité de ventilation à domicile, AP-HP, Hôpital Raymond Poincaré, 92380, Garches, France. adam.ogna@rpc.aphp.fr.
Adam
A
Ogna
Unité du Sommeil, AP-HP, Hôpital Raymond Poincaré, 92380, Garches, France.
Maria-Antonia
MA
Quera Salva
Service de Physiologie-Explorations Fonctionnelles, AP-HP, Hôpital Raymond Poincaré, 92380, Garches, France.
Helene
H
Prigent
Unité du Sommeil, AP-HP, Hôpital Raymond Poincaré, 92380, Garches, France.
Ghassane
G
Mroue
INSERM CIC 14.29, AP-HP, Hôpital Raymond Poincaré, 92380, Garches, France.
Isabelle
I
Vaugier
Service de Réanimation médicale et unité de ventilation à domicile, AP-HP, Hôpital Raymond Poincaré, 92380, Garches, France.
Djillali
D
Annane
Unité du Sommeil, AP-HP, Hôpital Raymond Poincaré, 92380, Garches, France.|Service de Physiologie-Explorations Fonctionnelles, AP-HP, Hôpital Raymond Poincaré, 92380, Garches, France.
Frederic
F
Lofaso
Service de Réanimation médicale et unité de ventilation à domicile, AP-HP, Hôpital Raymond Poincaré, 92380, Garches, France.|INSERM CIC 14.29, AP-HP, Hôpital Raymond Poincaré, 92380, Garches, France.
David
D
Orlikowski
D000136:Acid-Base Equilibrium / Q000502:physiology; D000328:Adult; D001785:Blood Gas Monitoring, Transcutaneous; D002940:Circadian Rhythm / Q000502:physiology; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007040:Hypoventilation / Q000453:epidemiology* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009468:Neuromuscular Diseases / Q000453:epidemiology* / Q000503:physiopathology; D010092:Oximetry; D012131:Respiratory Insufficiency / Q000453:epidemiology / Q000503:physiopathology; D012189:Retrospective Studies
Capno-oximetry; Diagnostic criteria; Neuromuscular disease; Nocturnal hypoventilation; Nocturnal oximetry; Prevalence