title: Cardiorespiratory function in stable methadone maintenance treatment (MMT) patients.
abstract: Patients in methadone maintenance programmes (MMT) often smoke tobacco and cannabis and many have ongoing illicit drug use. There is therefore potential for these patients to have abnormal cardiorespiratory function; however, few studies address this in stable MMT patients. We assessed resting cardiorespiratory function on 50 stable MMT patients (25 males, 25 females). Forty-six MMT patients were current tobacco smokers, 19 were current cannabis users and none were currently using opioids other than prescribed methadone. We defined abnormalities of respiratory function as those results outside the 95% confidence interval of reference values for normal subjects adjusted for age, weight, height and sex. Thirty-one (62%) MMT patients had reduced carbon monoxide transfer factor (D(L)CO); 17 (34%) had elevated single breath alveolar volume (V(A)) and 43 (86%) had a reduced D(L)CO/V(A) ratio. Six patients (12%) had reduced FEV1; one (2%) had reduced FVC; and nine (18%) had an obstructive ventilatory defect. Ten (20%) patients had PaCO2 higher than 45 mmHg and 14 (28%) had alveolar to arterial oxygen gradient (A-aPO2) higher than 15 mmHg. CXR, Echocardiography and ECG showed no significant abnormalities. We conclude that stable MMT patients have abnormalities of resting respiratory function which may be due to ongoing tobacco cigarette and current or past cannabis smoking.
authors.affiliation: Department of Respiratory and Sleep Disorders Medicine, Western Hospital, Victoria, Australia. Harry.Teichtahl@wh.org.au
authors.forename: Harry
authors.initials: H
authors.lastname: Teichtahl
authors.forename: David
authors.initials: D
authors.lastname: Wang
authors.forename: David
authors.initials: D
authors.lastname: Cunnington
authors.forename: Ian
authors.initials: I
authors.lastname: Kronborg
authors.forename: Cathy
authors.initials: C
authors.lastname: Goodman
authors.forename: Andy
authors.initials: A
authors.lastname: Prodromidis
authors.forename: Olaf
authors.initials: O
authors.lastname: Drummer
mesh_terms: D000293:Adolescent; D000328:Adult; D001944:Breath Tests; D004452:Echocardiography / Q000187:drug effects*; D004562:Electrocardiography / Q000187:drug effects*; D005260:Female; D005541:Forced Expiratory Volume / Q000187:drug effects*; D006556:Heroin Dependence / Q000534:rehabilitation*; D006801:Humans; D008297:Male; D008385:Marijuana Smoking / Q000009:adverse effects*; D008691:Methadone / Q000009:adverse effects / Q000627:therapeutic use*; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D017286:Polysomnography; D020182:Sleep Apnea, Central / Q000503:physiopathology*; D012907:Smoking / Q000009:adverse effects*; D015813:Substance Abuse Detection; D013375:Substance Withdrawal Syndrome / Q000503:physiopathology*
chemical_list: D010100:Oxygen; D008691:Methadone