Jens Callegari

Continuous non‐invasive PCO2 monitoring in weaning patients: Transcutaneous is advantageous over end‐tidal PCO2

Continuous partial pressure of carbon dioxide (PCO2) assessment is essential for the success of mechanical ventilation (MV). Non‐invasive end‐tidal PCO2 (PetCO2) and transcutaneous PCO2 (PtcCO2) measurements serve as alternatives to the gold standard arterial PCO2 (PaCO2) method, but their eligibility in critical care is unclear.

Interfaces and ventilator settings for long-term noninvasive ventilation in COPD patients

Introduction The establishment of high-intensity (HI) noninvasive ventilation (NIV) that targets elevated PaCO2 has led to an increase in the use of long-term NIV to treat patients with chronic hypercapnic COPD. However, the role of the ventilation interface, especially in more aggressive ventilation strategies, has not been systematically assessed. Methods Ventilator settings and NIV compliance were assessed in this prospective cross-sectional monocentric cohort study of COPD patients with pre-existing NIV. Daytime arterialized blood gas analyses and lung function testing were also performed. The primary end point was the distribution among study patients of interfaces (full-face masks [FFMs] vs nasal masks [NMs]) in a real-life setting. Results The majority of the 123 patients studied used an FFM (77%), while 23% used an NM. Ventilation settings were as follows: mean ± standard deviation (SD) inspiratory positive airway pressure (IPAP) was 23.2±4.6 mbar and mean ± SD breathing rate was 16.7±2.4/minute. Pressure support ventilation (PSV) mode was used in 52.8% of patients, while assisted pressure-controlled ventilation (aPCV) was used in 47.2% of patients. Higher IPAP levels were associated with an increased use of FFMs (IPAP <21 mbar: 73% vs IPAP >25 mbar: 84%). Mean compliance was 6.5 hours/day, with no differences between FFM (6.4 hours/day) and NM (6.7 hours/day) users. PaCO2 assessment of ventilation quality revealed comparable results among patients with FFMs or NMs. Conclusion This real-life trial identified the FFM as the predominantly used interface in COPD patients undergoing long-term NIV. The increased application of FFMs is, therefore, likely to be influenced by higher IPAP levels, which form part of the basis for successful application of HI-NIV in clinical practice.

Impact of Pseudomonas aeruginosa Infection on Respiratory Muscle Function in Adult Cystic Fibrosis Patients

Background:Pseudomonas aeruginosa infection impairs respiratory muscle function in adolescents with cystic fibrosis, but its impact on adult patients has not been characterised. Objectives: To investigate respiratory muscle function in adult cystic fibrosis patients according to P. aeruginosa status (repetitive samples over 12 months). Methods: The pressure-time index of the respiratory muscles (PTImus), a measure of their efficiency, served as the primary outcome. In addition, respiratory load and maximal respiratory muscle strength were assessed. Results: In 51 patients examined (65% female; median age 32 years, IQR 24-40), a median of 3.0 (IQR 2-4) different pathogens was found in each patient. The PTImus was 0.113 and 0.126 in Pseudomonas-positive (n = 33) and -negative (n = 18) patients, respectively (p = 0.53). Univariate analysis showed a lower PTImus in male than in female patients (p = 0.006). Respiratory muscle load and strength were otherwise comparable, with the exception of higher nasal sniff pressures in Pseudomonas-positive patients who were chronically infected (>50% of positive samples). Quality of Life (according to the Cystic Fibrosis Questionnaire-Revised) was higher if both respiratory load and the PTImus were low (high respiratory muscle efficiency). Conclusions: Chronic P. aeruginosa infection does not influence respiratory muscle efficiency in adult cystic fibrosis patients with otherwise multiple co-infections. In addition, patients with reduced respiratory muscle efficiency had worse Quality of Life.

Capillary PO 2 does not adequately reflect arterial PO 2 in hypoxemic COPD patients

Purpose To compare arterial (PaO2) with capillary (PcO2) partial pressure of oxygen in hypoxemic COPD patients because capillary blood gas analysis (CBG) is increasingly being used as an alternative to arterial blood gas analysis (ABG) in a non-intensive care unit setting, although the agreement between PcO2 and PaO2 has not been evaluated in hypoxemic COPD patients. Patients and methods Bland–Altman comparison of PaO2 and PcO2 served as the primary outcome parameter if PcO2 values were ≤60 mmHg and the secondary outcome parameter if PcO2 values were ≤55 mmHg. Pain associated with the measurements was assessed using a 100-mm visual analog scale. Results One hundred and two PaO2/PcO2 measurement pairs were obtained. For PcO2 values ≤60 mmHg, the mean difference between PaO2 and PcO2 was 5.99±6.05 mmHg (limits of agreement: −5.88 to 17.85 mmHg). For PcO2 values ≤55 mmHg (n=73), the mean difference was 5.33±5.52 mmHg (limits of agreement: −5.48 to 16.15 mmHg). If PaO2 ≤55 (≤60) mmHg was set as the cut-off value, in 20.6% (30.4%) of all patients, long-term oxygen therapy have been unnecessarily prescribed if only PcO2 would have been assessed. ABG was rated as more painful compared with CBG. Conclusions PcO2 does not adequately reflect PaO2 in hypoxemic COPD patients, which can lead to a relevant number of unnecessary long-term oxygen therapy prescriptions.

Is Outpatient Control of Long-Term Non-Invasive Ventilation Feasible in Chronic Obstructive Pulmonary Disease Patients?

Background: Long-term non-invasive ventilation (NIV) is an established and increasingly used treatment option for patients with chronic hypercapnic chronic obstructive pulmonary disease (COPD). Following inpatient NIV establishment, inpatient control visits regularly occur thereafter. However, it remains unclear whether such control visits can also be performed in an outpatient setting, which, in turn, would reduce costs, patient burden and the complications related to hospitalization. Objectives: To investigate an outpatient setting with predefined criteria for hospitalization for patients with chronic hypercapnic COPD. Methods: An outpatient clinic located within the hospital in the vicinity of the respiratory care unit provided predefined criteria for hospitalization of COPD patients receiving long-term NIV therapy. The results of this setting were retrospectively analysed. Results: A total of 130 outpatient visits (80 patients) were analysed. In 93 cases (71.5%), hospital admission was not necessary, while hospitalization was performed in 37 cases (28.5%). Out of these, 7 cases with acute conditions required prompt hospitalization. Patients without hospitalization had better PaCO2 values (45.40 ± 5.27 vs. 50.05 ± 8.04, p = 0.002) and Severe Respiratory Insufficiency Questionnaire Summary scores (55.54 ± 19.74 vs. 41.82 ± 19.59, p = 0.012). Conclusion: Outpatient control of long-term NIV in a hospital setting is feasible and has the capacity to identify stable COPD patients in whom NIV therapy is sufficient according to predefined criteria. These patients may not require hospitalization and may account for more than two thirds of cases.

Home noninvasive ventilatory support for patients with chronic obstructive pulmonary disease : patient selection and perspectives

Long-term or home mechanical noninvasive ventilation (Home-NIV) has become a well-established form of therapy over the last few decades for chronic hypercapnic COPD patients in European countries. However, meta-analyses and clinical guidelines do not recommend Home-NIV for COPD patients on a routine basis. In particular, there is ongoing debate about Home-NIV in chronic hypercapnic COPD regarding the overall effects, the most favorable treatment strategy, the selection of eligible patients, and the time point at which it is prescribed. The current review focuses on specific aspects of patient selection and discusses the various scientific as well as clinical-guided perspectives on Home-NIV in patients suffering from chronic hypercapnic COPD. In addition, special attention will be given to the topic of ventilator settings and interfaces.