Jan Hendrik Storre

High-intensity versus low-intensity non-invasive ventilation in patients with stable hypercapnic COPD: a randomised crossover trial

Rationale The conventional approach of low-intensity non-invasive positive pressure ventilation (NPPV) produces only minimal physiological and clinical benefits in patients with stable hypercapnic chronic obstructive pulmonary disease (COPD). Objectives To determine whether the novel approach of high-intensity NPPV is superior to low-intensity NPPV in controlling nocturnal hypoventilation. Methods A randomised controlled crossover trial comparing 6 weeks of high-intensity NPPV (using controlled ventilation with mean inspiratory pressures of 28.6±1.9 mbar) with low-intensity NPPV (using assisted ventilation with mean inspiratory pressures of 14.6±0.8 mbar) was performed in 17 patients with severe stable hypercapnic COPD. Results Two patients refused low-intensity NPPV and two patients dropped out while on low-intensity NPPV. Thirteen patients (mean forced expiratory volume in 1 s (FEV1) 0.76±0.29 l) completed the trial. High-intensity NPPV produced higher pneumotachographically-measured expiratory volumes, with a mean treatment effect of 96 ml (95% CI 23 to 169) (p=0.015). This resulted in a mean treatment effect on nocturnal arterial carbon dioxide tension (Paco2) of −9.2 mm Hg (95% CI −13.7 to −4.6) (p=0.001) in favour of high-intensity NPPV. Daily use of NPPV was increased in high-intensity NPPV compared with low-intensity NPPV, with a mean difference of 3.6 h/day (95% CI 0.6 to 6.7) (p=0.024). In addition, compared with baseline, only high-intensity NPPV resulted in significant improvements in exercise-related dyspnoea, daytime Paco2, FEV1, vital capacity and the Severe Respiratory Insufficiency Questionnaire Summary Score. Conclusions High-intensity NPPV is better tolerated by patients with severe chronic hypercapnic COPD and has been shown to be superior to the conventional and widely-used form of low-intensity NPPV in controlling nocturnal hypoventilation. High-intensity NPPV therefore offers a new promising therapeutic option for these patients.

Noninvasive ventilation during walking in patients with severe COPD: a randomised cross-over trial

It was hypothesised that noninvasive positive-pressure ventilation (NPPV) applied during walking prevents exercise-induced hypoxaemia and improves exercise performance in severe chronic obstructive pulmonary disease (COPD) patients already receiving long-term NPPV. A total of 20 COPD patients (mean±sd age 65.1±8.7 yrs, forced expiratory volume in one second 27±8% predicted and total lung capacity 116±27% pred) reporting dyspnoea, even during mild exertion, underwent two 6-min walking tests with a rollator and supplemental oxygen (2.1±0.9 L·min−1) in a randomised cross-over design: with and without pressure-limited NPPV as used at home (inspiratory:expiratory pressure 2.9±0.44:0.4±0.1 kPa (29±4:4±1 mbar), respiratory frequency 20±2 breaths·min−1). The arterial oxygen tension significantly increased by 1.39±1.43 kPa (95% confidence interval (CI) 0.71–2.07 kPa) after walking with NPPV, but significantly decreased by 1.43±1.06 kPa (95% CI −1.92 – −0.94 kPa) without NPPV. Dyspnoea, as assessed by the Borg dyspnoea scale, significantly decreased from 6 (interquartile range (IQR) 4.5–10) to 4 (1.5–4.5) and walking distance significantly increased from 209 (IQR 178–279) to 252 (203–314) m when walking was NPPV-aided. In chronic hypercapnic chronic obstructive pulmonary disease, high-intensity noninvasive positive-pressure ventilation can also be administered during walking with unchanged ventilator settings compared with settings used at rest, thus resulting in improved oxygenation, decreased dyspnoea and increased walking distance. Therefore, noninvasive positive-pressure ventilation during walking could prevent hypoxia-induced complications and could, in future, play a role in palliative care.

Guidelines for Non-Invasive and Invasive Mechanical Ventilation for Treatment of Chronic Respiratory Failure * Published by the German Society for Pneumology (DGP)

Martina Bogel, Weinmann GmbH, Hamburg Andreas Bosch, Heinen & Lowenstein GmbH, Bad Ems Jorg Brambring, Heimbeatmungsservice Brambring Jaschke GmbH, Unterhaching Stephan Budweiser, Klinik Donaustauf Dominic Dellweg, Fachkrankenhaus Kloster Grafschaft GmbH, Schmallenberg Peter Demmel, MDK Bayern, Munchen Rolf Dubb, Klinikum Stuttgart – Katharinenhospital Jens Geiseler, Asklepios Fachkliniken Munchen-Gauting Frank Gerhard, isb Ambulante Dienste gGmbH, Wuppertal Uwe Janssens, St.-Antonius-Hospital Eschweiler Thomas Jehser, Gemeinschaftskrankenhaus Havelhohe, Berlin Anne Kreiling, Deutsche Gesellschaft fur Muskelkranke e.V., Baunatal Thomas Kohnlein, Medizinische Hochschule Hannover Uwe Mellies, Universitatsklinikum Essen F. JoachimMeyer, Medizinische Universitatsklinik Heidelberg Winfried Randerath, Krankenhaus Bethanien gGmbH, Solingen Bernd Schonhofer, Klinikum Hannover Oststadt Bernd Schucher, Krankenhaus Groshansdorf Karsten Siemon, Fachkrankenhaus Kloster Grafschaft GmbH, Schmallenberg Helmut Sitter, Universitatsklinikum Giesen und Marburg GmbH (Vertreter der AWMF) Jan Hendrik Storre, Universitatsklinik Freiburg Stephan Walterspacher, Universitatsklinik Freiburg Steffen Weber-Carstens, Charite – Universitatsmedizin Berlin Wolfram Windisch, Universitatsklinik Freiburg MartinWinterholler, Krankenhaus Rummelsberg, Schwarzenbruck KurtWollinsky, Universitatsund Rehabilitationskliniken Ulm

Nocturnal non-invasive positive pressure ventilation: Physiological effects on spontaneous breathing

The dynamic process of how non-invasive positive pressure ventilation (NPPV) improves spontaneous ventilation is unclear. Therefore, daytime trends of blood gases and breathing pattern were assessed by measurements 0, 0.5, 1, 3, 7, 11 and 15 h after cessation of nocturnal controlled NPPV in patients with chronic hypercapnic respiratory failure. Twelve patients (six COPD/six restrictive) who were established on NPPV and 12 controls (six COPD/six restrictive) completed. PaCO2 decreased during controlled NPPV (P < 0.02). PaCO2 additionally decreased step by step during the first 3 h of spontaneous breathing after switching from NPPV to spontaneous breathing (P < 0.05), but remained unchanged in controls. The PaCO2 decrease was due to a stepwise increase in tidal volume (P < 0.05) at an unchanged breathing frequency. Accordingly, minute ventilation also stepwise increased (P < 0.03). There were no significant changes in controls. Improvements of PaCO2 and tidal volume occurred even after 5.7 +/- 3.1 days following first NPPV trials, but became more evident after 2 months. Maximal inspiratory mouth pressures increased in chronic obstructive pulmonary disease (COPD) patients (P < 0.05), and respiratory drive increased in restrictive patients (P < 0.05) following 2 months of NPPV. Lung function parameters and inspiratory impedance remained unchanged. Improvements in health-related quality of life were evident and were correlated to the decline of elevated bicarbonate levels (r = 0.72, P < 0.01). In conclusion, there is a stepwise adaptation process lasting 3h when switching from nocturnal controlled NPPV to daytime spontaneous breathing in which tidal volume increases and PaCO2 drops after an initial PaCO2 decrease while on NPPV.

Sedation during Flexible Bronchoscopy in Patients with Pre-Existing Respiratory Failure: Midazolam versus Midazolam plus Alfentanil

Background: The use of sedation during flexible bronchoscopy (FB) is undisputed; however, the combination of benzodiazepines and opiates, although reasonable, is suggested to cause hypoventilation, particularly in patients with pre-existing respiratory failure. Objectives: To assess respiratory function during FB. Methods: Transcutaneous PCO2 (PtcCO2), oxygen saturation, patients’ tolerance, time after FB until recovery and application of drug dosage were assessed in patients receiving either midazolam with alfentanil (n = 15) or midazolam alone (n = 15) for sedation for FB. Results: There were no differences in PtcCO2 values during FB between the two groups (all p > 0.05). However, PtcCO2 significantly increased over time in both groups (both p < 0.001; RM-ANOVA on ranks). Minimum oxygen saturation (SaO2) [89 (interquartile range 79.8/92.8) vs. 86 (interquartile range 82.3/87.8)%; p = 0.46] and the duration until recovery, i.e., achieving an ALDRETE score of ≧9 [30 (interquartile range 10/90) vs. 10 (interquartile range 10/105) min; p = 0.68] were comparable for monosedation and combined sedation, respectively. The total amount of midazolam [4.0 (interquartile range 4.0/4.0) vs. 2.0 (interquartile range 2.0/2.0) mg; p < 0.001] was lower in patients receiving combined sedation. Significantly lower scores for pain and asphyxia, and a clear tendency to less nausea and cough were reported by patients receiving combined sedation. Conclusions: Combined sedation during FB produced a comparable degree of desaturation and hypoventilation, and is associated with a comparable time to full recovery compared to monosedation in patients with pre-existing respiratory failure. Importantly, FB using combined sedation is better tolerated by patients despite only 50% midazolam consumption.

Clinical impact of leak compensation during non-invasive ventilation

BACKGROUND This study aimed to assess the impact of leak compensation capabilities during pressure- and volume-limited non-invasive positive-pressure ventilation (NPPV) in COPD patients. METHODS Fourteen patients with stable hypercapnic COPD who were receiving long-term NPPV were included in the study. For both modes of NPPV, a full face mask and an artificial leak in the ventilatory circuit were used at three different settings, and applied during daytime NPPV, either without leakage (setting I), with leakage during inspiration only (setting II), and with leakage during inspiration and expiration (setting III). Ventilation pattern was pneumotachy-graphically recorded. RESULTS NPPV was feasible with negligible leak volumes, indicating optimal mask fitting during the daytime (setting I). In the presence of leakage (settings II and III), the attempt to compensate for leak was only evident during pressure-limited NPPV, since inspiratory volumes delivered by the ventilator increased from 726+/-129 (setting I) to 1104+/-164 (setting II), and to 1257+/-166 (setting III) ml during pressure-limited NPPV, respectively (all p<0.001); however, they remained stable during volume-limited NPPV. Leak compensation resulted in a decrease in leakage-induced dyspnea. However, 83%/87% (setting II/III) of the additionally-delivered inspiratory volume during pressure-limited NPPV was also lost via leakage. Expiratory volume was higher in setting II compared to setting III (both p<0.001), indicating the presence of significant expiratory leakage. CONCLUSIONS The attempt at leak compensation largely feeds the leakage itself and only results in a marginal increase of tidal volume. However, pressure-limited--but not volume-limited--NPPV results in a clinically-important leak compensation in vivo. TRIAL REGISTRATION www.uniklinik-freiburg.de/zks/live/uklregister/Oeffentlich.html Identifier: UKF001272.

Techniques for the Measurement and Monitoring of Carbon Dioxide in the Blood

The relationship between an elevated partial pressure of carbon dioxide (Pco2) and reduced alveolar ventilation resulting from respiratory failure primarily affecting the respiratory pump was first reported during the 1952 Copenhagen polio epidemic. Several methods for Pco2 estimation, such as blood gas analyses, capnography, and transcutaneous Pco2 measurements, have since been developed to assess alveolar ventilation. The clinical setting in which CO2 measurement is valuable includes acute and chronic respiratory failure, transport, cardiopulmonary resuscitation, patient-controlled analgesia, and procedural sedation. The techniques that are currently available differ considerably regarding their accuracy, capacity to facilitate continuous assessment, side effects, availability, and their ability to assess additional information. Importantly, each technique has its own spectrum of indications and applications. Therefore, the different techniques are not competitive but, rather, complementary. As a consequence, it is reasonable to combine different techniques depending on specific clinical scenarios. This review summarizes the physiological background, historical development, instrument-specific technical aspects, and current recommendations for the clinical application of Pco2 assessment.

Target volume settings for home mechanical ventilation: great progress or just a gadget?

Home mechanical ventilation (HMV) is a well-established treatment option for patients with chronic hypercapnic respiratory failure, whereby non-invasive positive pressure ventilation (NPPV) serves as the predominant means of HMV delivery.1 ,2 In general, there are two physiologically-different modes of NPPV deliveries, volume-preset NPPV and pressure-preset NPPV. During volume-preset NPPV a fixed inspiratory volume (Vinsp) is set at the ventilator, while the inspiratory positive airway pressure (IPAP) varies depending on airway resistance. Conversely, Vinsp varies during pressure-preset NPPV, while IPAP remains fixed. The advantage of volume-preset NPPV is that Vinsp, and hence tidal volume, are relatively stable; however, this can lead to a breath-by-breath variation in IPAP levels that can become a burden for the patient, and the leakages that regularly occur during NPPV are not compensated for. In contrast, the Vinsp that is delivered during pressure-preset NPPV may be unstable due to increased airway resistance; however, given that the variation in IPAP is lower, this is often better tolerated by the patient. In addition, leak compensation is provided by pressure-preset NPPV, as shown by in vitro3 and in vivo4 studies. In addition, ventilators providing pressure-preset NPPV are cheaper. Thus, pressure-preset NPPV has become the predominant means of delivering HMV. Nevertheless, randomised controlled trials have shown that volume- and pressure-preset NPPV generally have comparable effects on improvements in blood gases, sleep quality and health-related quality of life (HRQL),5 ,6 although pressure-preset NPPV is reportedly better tolerated due to fewer gastrointestinal side effects.5 However, clinicians should always weigh the advantages and disadvantages of the two different approaches on an individual patient basis. Recently, the so-called hybrid modes have been developed to overcome the disadvantages of volume- and pressure-preset NPPV, respectively. …

Invasive home mechanical ventilation: living conditions and health-related quality of life.

Background: The number of patients with invasive home mechanical ventilation (HMV) following unsuccessful weaning is steadily increasing, but little is known about the living conditions and health-related quality of life (HRQL) in these patients. Objectives: To establish detailed information on living conditions and HRQL in patients with invasive HMV. Methods: The Severe Respiratory Insufficiency Questionnaire (SRI) was used to measure specific HRQL aspects in addition to patient interviews on individual living conditions during home visits. Results: Thirty-two patients with lung disease, most prominently COPD (n = 18), and neuromuscular disorders (n = 14) were included. The overall mean SRI summary scale score (range 0-100) was 53 ± 16, with a broad range amongst individuals (23-86). Neuromuscular patients were younger than those with lung diseases (49 ± 18 vs. 67 ± 11 years; p < 0.005), and although they had a higher nursing dependency and fewer comorbidities, they tended to have higher (better) SRI summary scale scores (58 ± 16 vs. 48 ± 15; p = 0.092). Living in a private home compared to living in nursing facilities did not influence the SRI scores. Conclusions: Patients undergoing invasive HMV primarily following unsuccessful weaning reported an individual HRQL which, when taken together, was highly heterogeneous and ranged from very good to extremely bad. Older patients with COPD and more comorbidities are likely to have a worse HRQL than neuromuscular patients, while the living situation does not influence the HRQL.

Nocturnal non-invasive positive pressure ventilation for COPD

There is an ongoing discussion on whether long-term non-invasive positive pressure ventilation (NPPV) should be used in chronic hypercapnic chronic obstructive pulmonary disease (COPD) patients. Early trials had failed to show convincing physiological and clinical effects using NPPV with assisted modes of ventilation and rather low inflation pressures. In particular, long-term survival could not be improved and findings on health-related quality of life had been conflicting. Remarkably, high-intensity NPPV using higher inflation pressures and back-up rates has recently been shown to be capable of improving blood gases, lung function, and health-related quality of life. Subsequently, a large study using this technique also showed a substantial improvement in the prognosis in these patients. Therefore, there is now increasing evidence to support physiologically effective NPPV in hypercapnic COPD patients, but how to best select patients still needs to be defined. The present article summarizes the physiological background and the current evidence on NPPV in COPD in addition to future considerations.