Identification of quality-of-life clusters by the Quebec sleep questionnaire in sleep apnea patients.

Patients with obstructive sleep apnea (OSA) may present different symptoms. The clinical importance of symptom clustering is supported by the difference in the incidence of cardiovascular diseases between hypersomnolent and non-hypersomnolent sleep apnea patients. The objective of this study was to determine if quality-of-life clusters could be identified from the Quebec Sleep Questionnaire (QSQ) in OSA patients. Latent class analysis was used to identify clusters in a multivariate analysis of dichotomic variables (presence or absence of symptoms) for each item the QSQ obtained from 147 patients who fulfilled the questionnaire during its validation and subsequent trials (75.5% males, age: 53 ± 11 years, body mass index (BMI): 30.4 ± 4.7 kg/m2, apnea/hypopnea index (AHI): 31.3 ± 14.8/h). Three clusters were identified. Quality of life was preserved in patients of cluster 1 (20.4% of patients). Patients of cluster 2 (32.6% of patients) had a moderately impaired quality of life, mainly due to daytime somnolence and poor sleep quality. Patients with impaired quality of life (cluster 3, 46.9% of patients) had an important impact in every domain of the QSQ with the highest sleepiness and daytime symptom impairments. Gender, BMI, and AHI did not differ between the three clusters. In conclusion, different quality-of-life clusters can be identified from the QSQ in sleep apnea patients. These clusters are similar to those reported previously. Further studies are needed to validate these clusters in larger and independent cohorts, to evaluate how they respond to OSA treatment, and their relationship with incident outcomes.

Clinical implementation of automated O2 titration in a tertiary care hospital.

Background: When treating acute respiratory failure, both hypoxemia and hyperoxemia should be avoided. SpO2 should be monitored closely and O2 flows adjusted accordingly. Achieving this goal might be easier with automated O2 titration compared to manual titration of fixed-flow O2 We evaluated the feasibility of using an automated O2 titration device in subjects treated for acute hypoxemic respiratory failure in a tertiary care hospital.Methods: Healthcare workers received education and training about oxygen therapy and were familiarized with an automated O2 titration device (FreeO2, Oxynov, Quebec City, Canada). A coordinator was available from 8 am to 5 pm during week days to provide technical assistance. The ability of the device to maintain SpO2 within the prescribed therapeutic window was recorded. Basic clinical information was recorded.Results: Subjects were enrolled from November 2020 to August 2022. We trained 508 healthcare workers on use of automated O2 titration which was finally used on 872 occasions in 763 subjects, distributed on the respiratory, COVID-19 and thoracic surgery wards and the emergency room. Clinical information could be retrieved for 609 (80%) subjects who were on the system for a median of 3 days (interquartile range: 2 to 6 days) representing 2567 subject-days of clinical experience with the device. In the 82 (14%) subjects for whom this information was available, the system maintained SpO2 within the prescribed targets 89% of the time. Ninety-six subjects experienced clinical deterioration as defined by the need to be transferred to the intensive care unit and/or requirement of high nasal flow oxygen but none of these events were judged to be related to the O2 device.Conclusions: Automated O2 titration could be successfully implemented in hospitalized subjects with hypoxemic respiratory failure from various causes. This experience should foster further improvement of the device and recommendations for an optimized utilization.

Impact of Surgical Positioning on the Occurrence of Postoperative Ipilateral Shoulder Pain After Lung Resection by Video-Assisted Thoracoscopy: A Randomized Trial.

OBJECTIVE: The aim of this study was to evaluate the impact of the ipsilateral arm position on ipsilateral shoulder pain after lung cancer resection by video-assisted thoracic surgery. DESIGN: A prospective randomized controlled trial. SETTING: A single academic center study. PARTICIPANTS: Patients undergoing video-assisted thoracic surgery pulmonary resection for cancer at the Institut Universitaire de Cardiologie et de Pneumologie de Québec from May 2020 to May 2022 were included. INTERVENTIONS: Patients randomly were assigned with a 1:1 ratio to a supported or suspended ipsilateral arm position. MEASUREMENTS AND MAIN RESULTS: Ipsilateral shoulder pain incidence, pain score, and opioid use were recorded in the postanesthesia care unit (PACU) on postoperative days 1 and 2. One hundred thirty-three patients were randomized, 67 in the suspended-arm group and 66 in the supported-arm group. Of the patients, 31% reported ipsilateral shoulder pain in the PACU with no difference between groups (19/67 [28.4%] v 22/66 patients (33.3%), p = 0.5767). There was no significant difference between the pain score in the PACU (3 [0-6] v 4 [0-6], p = 0.9055) at postoperative day 1 (4 [2-6] v 3 [2-5], p = 0.4113) and at postoperative day 2 (2 [0-5] v 2 [1-4], p = 0.9508). Ipsilateral shoulder pain score decreased rapidly on postoperative day 2. There was no statistical difference in opioid and gabapentinoid use between the groups. CONCLUSIONS: Ipsilateral arm position seems to have no impact on ipsilateral shoulder pain.

Use of Palliative Oxygen in Cancer Patients.

Background: Despite the lack of evidence to support the use of palliative oxygen to relieve dyspnea at the end of life, its prescription is widespread and often supported by local and national practice guidelines. Objectives: The objectives of this study were (1) to determine to what extent oxygen prescriptions meet the proposed prescription criteria in our institution, (2) to examine the indication of individual prescriptions in relation to the severity of dyspnea and (3) to review the utilization of opioids in patients receiving palliative oxygen. Methods: Retrospective chart review of cancer patients who were prescribed palliative oxygen between April 2015 and January 2020 through a respiratory home care program in Quebec City, Canada. According to provincial prescription guidelines, palliative oxygen was provided and reimbursed in case of severe hypoxemia (pulse oximetry saturation at rest < 88%) in cancer patients with an estimated prognosis of less than 3 months. Results: 134 patients receiving palliative oxygen were included; 25 (19%) did not fulfill reimbursement criteria. Median survival was 44 days. At initiation of palliative oxygen, 48 patients (36%) had only mild or moderate dyspnea (Medical Research Council dyspnea score 1-3), 26 (19%) did not receive opioids, and 9 (7%) were prescribed palliative oxygen without being dyspneic or receiving opioids. Conclusion: Most prescriptions of palliative oxygen met the proposed prescription criteria in our institution. Half of those who received palliative oxygen were only mildly dyspneic and/or were not receiving opioids at the time of the prescription.

Exercise testing and postoperative complications after minimally invasive lung resection: A cohort study.

Background: Peak oxygen uptake ( V ˙ O 2 ) during cardiospulmonary exercise testing (CPET) is used to stratify postoperative risk following lung cancer resection but peak V ˙ O 2 thresholds to predict post-operative mortality and morbidity were derived mostly from patients who underwent thoracotomy. Objectives: We evaluated whether peak V ˙ O 2 or other CPET-derived variables predict post-operative mortality and cardiopulmonary morbidity after minimally invasive video-assisted thoracoscopic surgery (VATS) for lung cancer resection. Methods: A retrospective analysis of patients who underwent VATS lung resection between 2002 and 2019 and in whom CPET was performed. Logistic regression models were used to determine predictors of postoperative outcomes until 30 days after surgery. The ability of peak V ˙ O 2 to discriminate between patients with and without post-operative complications was evaluated using Receiver operating characteristic (ROC) analysis. Results: Among the 593 patients, postoperative cardiopulmonary complications occurred in 92 (15.5%) individuals, including three deaths. Mean peak V ˙ O 2 was 18.8 ml⋅kg-1⋅min-1, ranging from 7.0 to 36.4 ml⋅kg-1⋅min-1. Best predictors of postoperative morbidity and mortality were peripheral arterial disease, bilobectomy or pneumonectomy (versus sublobar resection), preoperative FEV1, peak V ˙ O 2 , and peak V ˙ E / V ˙ C O 2 . The proportion of patients with peak V ˙ O 2 of < 15 ml⋅kg-1⋅min-1, 15 to < 20 ml⋅kg-1⋅min-1 and ≥ 20 ml⋅kg-1⋅min-1 experiencing at least one postoperative complication was 23.8, 16.3 and 10.4%, respectively. The area under the ROC curve for peak V ˙ O 2 was 0.63 (95% CI: 0.57-0.69). Conclusion: Although lower peak V ˙ O 2 was a predictor of postoperative complications following VATS lung cancer resection, its ability to discriminate patients with or without complications was limited.

Short-Term Oxygen Therapy Outcomes in COPD.

Rationale: Short-term oxygen therapy (STOT) is often prescribed to allow patients with chronic obstructive pulmonary disease (COPD) to be discharged safely from hospital following an acute illness. This practice is widely accepted without being based on evidence. Purpose: Our objective was to describe the characteristics and outcomes of patients with COPD who received STOT. Patients and Methods: The study was a secondary analysis of the INOX trial, a 4-year randomised trial of nocturnal oxygen in COPD. The trial indicated that nocturnal oxygen has no significant effect on survival or progression to LTOT, allowing our merging of patients who received nocturnal oxygen and those who received placebo into a single cohort to study the predictors and outcomes of STOT regardless of the treatment received during the trial. Results: Among the 243 participants in the trial, 60 required STOT on at least one occasion during follow-up. Patients requiring STOT had more severe dyspnoea and lung function impairment, and lower PaO2 at baseline than those who did not. STOT was associated with subsequent LTOT requirement (hazard ratio [HR]: 4.59; 95% confidence interval [CI]: 2.98-7.07) and mortality (HR: 1.93; 95% CI: 1.15-3.24). The association between STOT and mortality was confounded by age, disease severity and comorbidities. Periods of STOT of more than one month and/or repeated prescriptions of STOT increased the probability of progression to LTOT (OR: 5.07; 95% CI: 1.48-18.8). Conclusion: Following an acute respiratory illness in COPD, persistent hypoxaemia requiring STOT is a marker of disease progression towards the requirement for LTOT.

Transthoracic needle biopsy versus surgical diagnosis for solid pulmonary nodules.

Background: When investigating solitary pulmonary nodules (SPN), non-surgical [such as transthoracic needle biopsy (TTNB)] or surgical biopsies can be performed. There is a paucity of data comparing these two approaches. Methods: This descriptive study is a retrospective analysis of a cohort of 149 patients who underwent TTNB and/or surgery for a SPN >8 mm but ≤3 cm between January and December 2016, at Institut universitaire de cardiologie et de pneumologie de Québec (IUCPQ). Our primary objective was to evaluate the proportion of patients investigated with TTNB vs. surgical diagnosis in our center. Secondary objectives were to examine the distribution of diagnoses (malignancy vs. benign lesion), to evaluate the proportion of TTNB that would yield a benign diagnosis and permit to avoid surgery, to evaluate if delays to surgery were longer when preoperative TTNB was performed, and if operative times were longer with upfront surgery. Results: In our cohort, 87 patients (58%) underwent TTNB, while 62 (42%) had an upfront surgical procedure. One hundred and twenty-eight patients (86%) had a malignant diagnosis. Thirteen patients out of the 87 biopsied (15%) avoided surgery owing to a benign biopsy result, or a non-specific diagnosis and a physician reassured enough to decide for radiological surveillance, while 5/62 patients (8%) who underwent upfront surgery had a benign diagnosis. There was no significant difference in delays from imaging to surgery or in operative time between patients with or without prior TTNB. Conclusions: In this unicentric retrospective cohort of patients investigated for SPN, the malignancy rate was high (86%), which seemed to limit the applicability of prediction models. Adherence to guidelines for the investigation of SPN by physicians seemed suboptimal. More real-world prospective studies are needed to compare non-surgical and surgical biopsies. There is also a need for simpler nodule evaluation algorithms.

Assessment of Clinical Worsening End Points as a Surrogate for Mortality in Pulmonary Arterial Hypertension: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

BACKGROUND: Clinical worsening (CW) is a composite end point commonly used in pulmonary arterial hypertension (PAH) trials. We aimed to assess the trial-level surrogacy of CW for mortality in PAH trials, and whether the various CW components were similar in terms of frequency of occurrence, treatment-related relative risk (RR) reduction, and importance to patients. METHODS: We searched MEDLINE, Embase, and the Cochrane Library (January 1990 to December 2020) for trials evaluating the effects of PAH therapies on CW. The coefficient of determination between the RR for CW and mortality was assessed by regression analysis. The frequency of occurrence, RR reduction, and importance to patients of the CW components were assessed. RESULTS: We included 35 independent cohorts (9450 patients). PAH therapies significantly reduced CW events (RR, 0.64 [95% CI, 0.55-0.73]), including PAH-related hospitalizations (RR, 0.61 [95% CI, 0.47-0.79]), treatment escalation (RR, 0.57 [95% CI, 0.38-0.84]) and symptomatic progression (RR, 0.58 [95% CI, 0.48-0.69]), and modestly reduced all-cause mortality when incorporating deaths occurring after a primary CW-defining event (RR, 0.860 [95% CI, 0.742-0.997]). However, the effects of PAH-specific therapies on CW only modestly correlated with their effects on mortality (R2trial, 0.35 [95% CI, 0.10-0.59]; P<0.0001), and the gradient in the treatment effect across component end points was large in the majority of trials. The weighted proportions of CW-defining events were hospitalization (33.5%) and symptomatic progression (32.3%), whereas death (6.7%), treatment escalation (5.6%), and transplantation/atrioseptostomy (0.2%) were infrequent. CW events were driven by the occurrence of events of major (49%) and mild-to-moderate (37%) importance to patients, with 14% of the events valued as critical. CONCLUSIONS: PAH therapies significantly reduced CW events, but study-level CW is not a surrogate for mortality in PAH trials. Moreover, components of CW largely vary in frequency, response to therapy, and importance to patients and are thus not interchangeable. REGISTRATION: URL: https://www.crd.york.ac.uk/PROSPERO; Unique identifier: CRD42020178949.

Home oxygen for moderate hypoxaemia in chronic obstructive pulmonary disease: a systematic review and meta-analysis.

BACKGROUND: Long-term oxygen therapy (LTOT) improves survival in patients with chronic obstructive pulmonary disease (COPD) and severe hypoxaemia. However, the best method of management of moderate hypoxaemia not qualifying for LTOT (including isolated nocturnal desaturation) is uncertain. We examined the effect of home oxygen (either LTOT or nocturnal oxygen therapy) on overall survival in patients with COPD and moderate hypoxaemia. METHODS: In this systematic review and meta-analysis, we searched MEDLINE, Embase, the Cochrane Central Register of Controlled Trials, CINHAL, and Web of Science from database inception to Jan 13, 2022, for parallel-group randomised trials of long-term or nocturnal oxygen in patients with COPD and moderate daytime hypoxaemia or isolated nocturnal desaturation, or both. Control groups received usual care or ambient air through sham concentrators (placebo) throughout the study period. The primary outcome of interest was 3-year mortality. Crossover trials and trials of oxygen in severe hypoxaemia were excluded. Two reviewers applied inclusion and exclusion criteria to titles and abstracts and screened the full-text articles and reference lists of relevant studies. Aggregate data were extracted manually in duplicate using structured data collection forms. Methodological quality was assessed using the Cochrane Risk of Bias tool. Random-effects meta-analysis was used to pool individual studies. We considered the minimal clinically important difference for home oxygen to be a relative risk reduction in mortality at 3-year follow-up of 30-40%. The meta-analysis is registered on PROSPERO, CRD42021225372. FINDINGS: We identified 2192 studies and screened 1447 after removal of duplicates, of which 161 were subjected to full-text screening, and six were identified as being eligible for inclusion. These six randomised trials were published between 1992 and 2020 and the quality of evidence was high. In the primary meta-analysis (five trials; 1002 patients), we found the effect of home oxygen in reducing 3-year mortality to be small or absent (relative risk 0·91 [95% CI 0·72-1·16]; τ2 = 0·00), hence the lower limit of the 95% CI did not meet the prespecified minimal clinically important difference. INTERPRETATION: The results of our meta-analysis suggest that home oxygen probably makes little or no difference to 3-year mortality in patients with COPD and moderate hypoxaemia. The data do not support the widespread use of home oxygen in this patient population. FUNDING: None.

Cost-Effectiveness of an Extended Home Visit Program for Oxygen-Dependent COPD Patients.

BACKGROUND: Long-term oxygen therapy in COPD is usually supervised through home-care respiratory programs. Such programs often involve an intensive education intervention at the initiation of long-term oxygen therapy, followed by an extended follow-up period that aims toward home oxygen adherence. The objective of this study was to estimate the cost-effectiveness ratio of such a maintenance program. METHODS: A simulation model was developed that compared 2 strategies after the intensive education intervention: (1) enrollment and (2) no enrollment in a maintenance program. The study population consisted of a hypothetical cohort of 200 patients (100 patients per group; mean age, 74 years; 45% men; mean FEV1 of 43% predicted value; and mean resting PaO2 while breathing air, 50 mm Hg). Effectiveness assumptions of the program were derived from a current literature review. The primary outcome was the ratio of the incremental cost of the program per quality-adjusted life-years gained. Only direct costs were considered; a health-care system perspective was adopted. Costs are reported in 2020 Canadian dollars (Can $). RESULTS: Over a 5-year period, an extended home-visit program may prevent 9 deaths and provide an additional 39 years of life and 24 quality-adjusted life-years. Compared with usual care (ie, no enrollment in the maintenance program), the incremental cost-effectiveness ratio was Can $17,197 per quality-adjusted life-years gained. Sensitivity analyses demonstrated the robustness of the model. Only a reduction in adherence of 25% per year would increase the incremental cost-effectiveness ratio per quality-adjusted life-years beyond the threshold of Can $50,000 that is usually considered as acceptable from a health-care system perspective. CONCLUSIONS: An extended home-visit program to maintain or improve adherence to long-term oxygen therapy in patients with COPD would most likely be cost-effective.

Safety of Bronchoscopy after Acute Coronary Syndrome.

BACKGROUND: Bronchoscopy is a safe procedure which is frequently performed for the investigation of respiratory diseases. Current guidelines recommend to delay bronchoscopy for 4-6 weeks after acute coronary syndrome (ACS), as this period is theoretically considered at risk for new onset of ACS. We therefore aimed to evaluate the safety and the tolerance of bronchoscopy in patients with ACS (≤30 days) and to compare outcomes with matched controls. METHODS: All consecutive patients who had a bronchoscopy performed in the first 30 days after an ACS in the bronchoscopy suite were included. A group of patients with ACS who did not undergo bronchoscopy (controls) were also included and matched for age, sex, type of ACS, and severity of ACS (GRACE score). RESULTS: Of the 13,646 patients who underwent bronchoscopy between 2010 and 2019, 2,181 had an history of ACS and among those, 87 patients had an ACS (19 with STEMI, 52 with NSTEMI, and 16 unstable angina). Mean interval between ACS and bronchoscopy was of 10.1 ± 8.9 days. Systolic blood pressure and heart rate significantly increased and oxygen saturation significantly decreased during bronchoscopy. The most frequent adverse event was desaturation which occurred in 26% of patients. Reinfarction rate (1.1% vs. 2.3% p = 1.00) and all-cause 30-day mortality (2.3% vs. 4.6%; p = 0.68) were similar in patients who underwent bronchoscopy and in matched controls (n = 87). CONCLUSION: Our study reinforces the safety of bronchoscopy after ACS. When clinically indicated with potential benefits outweighing risks, ACS should not contraindicate bronchoscopy.

Palliative Systemic Therapy Given near the End of Life for Metastatic Non-Small Cell Lung Cancer.

BACKGROUND: The use of chemotherapy near end of life (EOL) for various cancers is increasing and has been shown to be associated with delayed access to palliative care (PC) and increased aggressiveness in EOL care, without any benefit on survival. METHODS: This retrospective study included 90 patients with metastatic non-small cell lung cancer (NSCLC) who received at least one line of palliative systemic anticancer therapy (SACT) and died between 1 November 2014, and 31 October 2016, at Institut universitaire de cardiologie et de pneumologie de Québec (IUCPQ). Our primary objective was to evaluate the proportion of patients with NSCLC receiving SACT within 30 days of death. Secondary outcomes were to determine the mean and median delays between the administration of the last treatment and death, and to evaluate if there were differences in characteristics and outcomes (including overall survival (OS)) between patients treated or not within 30 days of death. RESULTS: In our cohort, 22% of patients received SACT within 30 days of death. For the entire cohort, the mean delay between the last treatment and death was 94 days, and the median was 57 days. There were no statistically significant differences between the two groups in terms of baseline characteristics. Use of SACT near EOL was associated with decreased access to PC, higher rates of in hospital death, decreased use of medical aid in dying (MAiD), and a shorter median OS (4.0 vs. 9.0 months). CONCLUSIONS: In this retrospective cohort of patients with metastatic NSCLC, 22% of patients received SACT within 30 days of death, with a negative impact on access to PC, higher rates of in hospital death, decreased use of MAiD and palliative sedation, and a shorter median OS.

Post-pneumonectomy patients undergoing cardiac surgery: A case series.

BACKGROUND: Data regarding post-pneumonectomy patient assessment for cardiac surgery is scarce. This retrospective study was conducted to define early and late outcomes in these patients, and to identify risk factors for poor outcomes. METHODS: This study included patients with a previous history of pneumonectomy undergoing on-pump cardiac surgery with median sternotomy. The institutional database was reviewed from 1992 to 2018. RESULTS: Sixteen post-pneumonectomy patients (all lung cancer) were identified. The age range was 53-81 years. The mean FEV1/FVC was 69%. The mean EuroSCORE II was 11.6%. Four patients had heart failure symptoms in the 2 weeks before surgery. Seven patients had isolated coronary artery bypass grafting (CABG) and six patients had CABG + aortic valve replacement (AVR). The major perioperative events affecting the ease and outcomes of the surgical procedures were structural shifts (5), extensive adhesions on heart and vessels (5), and extensive calcification of heart components (5). Important postoperative complications were respiratory (7), infections (5), and acute kidney injury (5). The median hospital length of stay was 7 days. Five patients died in hospital (none with isolated CABG) with a preoperative New York Heart Association classification (NYHA) of III-IV, a cardiopulmonary bypass time of 175.2 min and an aortic cross-clamp time of 104.0 min. The long-term survival data were recorded with a mean follow-up of 7.3 ± 7.1 years (range from 0 to 19). The overall, 5-year survival, was 50% for all cardiac surgeries, 71% for isolated CABG surgeries, and 17% for CABG + AVR surgeries, respectively. CONCLUSION: Post-pneumonectomy patients have acceptable postoperative outcomes and survival. Simple and short surgeries with careful planning can yield favorable outcomes for this high-risk subgroup of patients.

Dilation versus laser resection in subglottic stenosis: protocol for a prospective international multicentre randomised controlled trial (AERATE trial).

INTRODUCTION: Subglottic stenosis (SGS) is a rare condition that results from progressive narrowing of the upper airways. Outcomes and treatment options depend on the benign or complex nature of the stenosis. Treatment options for SGS include surgery and endoscopic techniques. The main endoscopic techniques used are dilation and laser resection. Observational and retrospective studies suggest that endoscopic laser resection may be more effective than dilation. We, therefore, aimed to compare the effectiveness of dilation and laser resection in preventing recurrence of SGS. METHODS AND ANALYSIS: AERATE (dilAtion vs laser Endoscopic Resection in subglottic trAcheal sTEnosis) is a multicentre, investigator-initiated, randomised controlled trial, comparing endoscopic dilation to endoscopic laser resection for simple benign SGS (less than 1 cm long without underlying cartilaginous damage) referred for endoscopic treatment (first treatment or recurrence). The study will be conducted in three centres in France and one in Canada with other centres from France and Canada expected to join. The primary outcome is the recurrence rate of stenosis at 2 years. Recurrence is defined as having a new onset of symptoms along with a stenosis of more than 40% (confirmed by bronchoscopy) requiring a new procedure. A sample size of 100 patients is calculated for the primary endpoint assuming a 10% recurrence rate in the laser resection group and 33% in the dilation group with a statistical significance level of 5%, a power of 80%. ETHICS AND DISSEMINATION: This study is approved by local and national ethics committees as required. Results will be published, and trial data will be made available. TRIAL REGISTRATION NUMBER: NCT04719845.

Oximetry neither to prescribe long-term oxygen therapy nor to screen for severe hypoxaemia.

BACKGROUND AND OBJECTIVE: Transcutaneous pulse oximetry saturation (S pO2 ) is widely used to diagnose severe hypoxaemia and to prescribe long-term oxygen therapy (LTOT) in COPD. This practice is not based on evidence. The primary objective of this study was to determine the accuracy (false positive and false negative rates) of oximetry for prescribing LTOT or for screening for severe hypoxaemia in patients with COPD. METHODS: In a cross-sectional study, we correlated arterial oxygen saturation (S aO2 ) and S pO2 in patients with COPD and moderate hypoxaemia (n=240) and calculated the false positive and false negative rates of S aO2 at the threshold of ≤88% to identify severe hypoxaemia (arterial oxygen tension (P aO2 ) ≤55 mmHg or P aO2 <60 mmHg) in 452 patients with COPD with moderate or severe hypoxaemia. RESULTS: The correlation between S aO2 and S pO2 was only moderate (intra-class coefficient of correlation: 0.43; 95% confidence interval: 0.32-0.53). LTOT would be denied in 40% of truly hypoxaemic patients on the basis of a S aO2 >88% (i.e., false negative result). Conversely, LTOT would be prescribed on the basis of a S aO2 ≤88% in 2% of patients who would not qualify for LTOT (i.e., false positive result). Using a screening threshold of ≤92%, 5% of severely hypoxaemic patients would not be referred for further evaluation. CONCLUSIONS: Several patients who qualify for LTOT would be denied treatment using a prescription threshold of saturation ≤88% or a screening threshold of ≤92%. Prescription of LTOT should be based on P aO2 measurement.