Sven Stieglitz

A Novel Extracorporeal CO2 Removal System: Results of a Pilot Study of Hypercapnic Respiratory Failure in Patients With COPD

BACKGROUND Hypercapnic respiratory failure in patients with COPD frequently requires mechanical ventilatory support. Extracorporeal CO2 removal (ECCO2R) techniques have not been systematically evaluated in these patients. METHODS This is a pilot study of a novel ECCO2R device that utilizes a single venous catheter with high CO2 removal rates at low blood flows. Twenty hypercapnic patients with COPD received ECCO2R. Group 1 (n = 7) consisted of patients receiving noninvasive ventilation with a high likelihood of requiring invasive ventilation, group 2 (n = 2) consisted of patients who could not be weaned from noninvasive ventilation, and group 3 (n = 11) consisted of patients on invasive ventilation who had failed attempts to wean. RESULTS The device was well tolerated, with complications and rates similar to those seen with central venous catheterization. Blood flow through the system was 430.5 ± 73.7 mL/min, and ECCO2R was 82.5 ± 15.6 mL/min and did not change significantly with time. Invasive ventilation was avoided in all patients in group 1 and both patients in group 2 were weaned; PaCO2 decreased significantly (P < .003) with application of the device from 78.9 ± 16.8 mm Hg to 65.9 ± 11.5 mm Hg. In group 3, three patients were weaned, while the level of invasive ventilatory support was reduced in three patients. One patient in group 3 died due to a retroperitoneal bleed following catheterization. CONCLUSIONS This single-catheter, low-flow ECCO2R system provided clinically useful levels of CO2 removal in these patients with COPD. The system appears to be a potentially valuable additional modality for the treatment of hypercapnic respiratory failure.

Adaptive servo-ventilation in patients with coexisting obstructive sleep apnoea/hypopnoea and Cheyne-Stokes respiration.

OBJECTIVE The coexistence of obstructive (OSAS) and central sleep apnoea (CSA) and Cheyne-Stokes respiration (CSR) is common in patients with and without underlying heart diseases. CPAP has been shown to improve CSA/CSR by about 50%, but recent data suggest maximal suppression of CSA is important in improving clinical outcomes in heart failure patients. Adaptive servo-ventilation (ASV) effectively suppresses CSA/CSR in heart failure, but only few trials have considered patients with coexisting OSAS and CSA/CSR. METHODS Prospective, observational pilot study to evaluate the efficacy of a new ASV device, the BiPAP AutoSV, in 10 male consecutive patients with coexisting OSAS and CSA/CSR with and without heart failure over eight weeks. Six had stable heart failure. MEASUREMENTS AND RESULTS The total AHI improved from 48.9+/-20.6/h to 8.7+/-7.4, the obstructive AHI from 15.8+/-16.2/h to 2.6+/-2.5/h and the central AHI from 33.1+/-10.8/h to 6.1+/-5.9/h (all p<0.01). Furthermore, there was a significant improvement in sleep profile and respiratory related arousals. The six patients with cardiovascular disease, including three with congestive heart failure, showed similar improvements in all parameters. CONCLUSIONS BiPAP AutoSV was effective in reducing all types of respiratory disturbances in coexisting OSAS and CSA/CSR with and without heart failure. Further studies comparing the long-term clinical efficacy of this device against CPAP are warranted.

Comparison of Automatic and Continuous Positive Airway Pressure in a Night-by-Night Analysis: A Randomized, Crossover Study

Background: Long-term compliance is suboptimal in the treatment of the obstructive sleep apnea syndrome (OSAS). Objectives: We compared the efficacy of and the adherence to automatic continuous positive airway pressure (APAP) and constant continuous positive airway pressure (CPAP) based on a night-by-night analysis. Methods: We performed a randomized, single-blind crossover study in 20 patients with moderate-to-severe OSAS. After diagnostic polysomnography and manual titration, patients were treated for 8 weeks with both constant CPAP and APAP in random order. Compliance and leakage were analyzed night by night using the software LOGSoft® of the Magellan® iPAP device. Results: The reduction in the apnea/hypopnea index (baseline 32.9 ± 19.1/h, CPAP 4.6 ± 2.9/h, APAP 5.6 ± 3.6/h; p < 0.001 compared to baseline) and the Epworth Sleepiness Scale (baseline 10.3 ± 5.7, CPAP 6.6 ± 4.8, APAP 4.9 ± 4.6; p < 0.001 compared to baseline) did not significantly differ between the treatment modes. Leakage time and compliance per night were not statistically different (leakage CPAP 31 ± 57 min, APAP 25 ± 49 min; compliance CPAP 383 ± 116 min, APAP 382 ± 107 min). There was no correlation between leakage and compliance. Thirteen patients (65%) preferred APAP at the end of the study. Conclusions: Treatment efficacy and adherence are similar with CPAP and APAP. There is a trend towards lower leakage with APAP therapy. Patients prefer the automatic mode to fixed pressure.

Evaluation of a Noninvasive Algorithm for Differentiation of Obstructive and Central Hypopneas

STUDY OBJECTIVES The clear discrimination of central and obstructive hypopneas is highly relevant to avoid misinterpretation and inappropriate treatment of complicated breathing patterns. Esophageal manometry is the accepted standard for the differentiation of the phenotypes of sleep apnea. However, it is limited in its use due to poor acceptance by patients and therefore rarely performed in routine clinical practice. Flattening of the inspiratory airflow curve, paradoxical breathing, arousal position, sleep stages, and breathing pattern at the end of the hypopnea can each give hints for the classification of hypopnea. The aim of this study was to evaluate a standardized algorithm combining these polysomnographic parameters for the discrimination of hypopneas in everyday practice. METHODS Polysomnography (PSG) and esophageal manometry were performed in 41 patients suspected of having sleep apnea (33 male, 52.3 ± 15.9 yr, body mass index 28.6 ± 4.5 kg/m(2)). Hypopneas were independently discriminated by blinded investigators based on esophageal pressure and the PSG-based algorithm. Only those hypopneas that could be differentiated with both methods were evaluated. RESULTS There were 1,175 of 1,837 hypopneas (64%) that could be defined by esophageal pressure, 1,812 (98.6%) by the PSG-based algorithm. Using esophageal pressure as a reference, the new algorithm correctly defined 76.9% of central and 60.5% of obstructive hypopneas. The overall accuracy was 68%. The isolated analysis of single PSG parameters revealed a lower accuracy compared with the combined algorithm. CONCLUSIONS The PSG-based algorithm allows for discrimination of most hypopneas. It is advantageous in comparison with esophageal pressure because it is noninvasive and less impaired by artefacts. Therefore, it is a potentially helpful tool for sleep specialists. CITATION Randerath WJ; Treml M; Priegnitz C; Stieglitz S; Hagmeyer L; Morgenstern C. Evaluation of a noninvasive algorithm for differentiation of obstructive and central hypopneas. SLEEP 2013;36(3):363-368.

Anticyclic modulated ventilation versus continuous positive airway pressure in patients with coexisting obstructive sleep apnea and Cheyne–Stokes respiration: a randomized crossover trial

BACKGROUND Although coexisting obstructive sleep apnea (OSA) and Cheyne-Stokes respiration (CSR) occur frequently in patients with heart diseases, optimal treatment remains unclear. Positive airway pressure (PAP) effectively treats OSA and adaptive servo-ventilation (ASV) has been shown to improve CSR. We compared a new treatment algorithm combining automatic continuous positive airway pressure (APAP) and ASV (anticyclic modulated ventilation, ACMV) versus continuous positive airway pressure (CPAP). METHODS Thirty-nine patients (35 male, four female; aged 65.5±9.7 years; body mass index, 31.0±5.9 kg/m2) with underlying heart disease and coexisting OSA and CSR were enrolled. After diagnostic polysomnography (PSG) and CPAP titration, patients were randomized either to CPAP or to ACMV for four weeks of treatment in a crossover design. RESULTS Total apnea-hypopnea index (AHI) was 49.0±18.8/h at baseline, 12.3±14.6/h with CPAP (P<0.001 vs baseline), and 3.7±5.6/h with ACMV (P<0.001 vs. baseline and vs. CPAP). Obstructive AHI was 20.7±14.4/h at baseline, 5.1±9.3/h with CPAP (P<0.001 vs. baseline), and 0.4±0.4/h with ACMV (P<0.001 vs. baseline and vs. CPAP). Central AHI was 28.3±13.4/h at baseline, 7.2±9.7/h with CPAP (P<0.001 vs baseline) and 3.3±5.4/h with ACMV (P<0.001 vs. baseline and vs. CPAP). Ejection fraction was increased significantly (from 38.6±15.6 to 44.4±12.2%) only with ACMV. Subjective sleepiness significantly improved only with CPAP whereas objective sleep quality and treatment adherence were not different between both treatment modalities. CONCLUSION ACMV is an effective treatment option in patients with coexisting OSA and CSR. It is superior to CPAP in reducing total AHI as well as obstructive and central AHI.

Comparison of manual titration and automatic titration based on forced oscillation technique, flow and snoring in obstructive sleep apnea

BACKGROUND Continuous positive airway pressure (CPAP) treatment in obstructive sleep apnea syndrome (OSAS) requires pressure titration usually performed during attended in-hospital polysomnography. This manual titration procedure is not well standardized. The aim of the study was to ascertain whether a new automatic titration device is as effective as standard manual titration in determining constant CPAP pressure. METHODS We included 38 patients with a newly diagnosed OSAS. Participants were randomly assigned to attended in-laboratory manual titration and automatic titration in two consecutive nights. Fixed CPAP pressure was set at the optimal pressure determined during the second night. The follow-up period was 6 weeks. Main outcomes were apnea/hypopnea index (AHI) and Epworth sleepiness scale (ESS). RESULTS AHI (manual: baseline 40.5+/-21.5/h vs. treatment 6.4+/-3.3/h (p<0.001); automatic: 53.3+/-28.1/h vs. 7.8+/-3.3/h (p<0.001)) and ESS (manual: 11.3+/-4.7 vs. 8.8+/-5.1 (ns); automatic: 11.5+/-5.6 vs. 7.0+/-3.8 (p<0.05)) showed a similar improvement in both groups. Pressure recommendation by the device and the technician, although not statistically different (8.7+/-2.9 vs. 9.0+/-3.3 mbar), corresponded only in 50% of the patients. CONCLUSIONS Automatic titration effectively predicts constant CPAP pressure for long-term treatment when performed during an attended polysomnography. Careful evaluation of raw data and polysomnography recording is mandatory before choosing a fixed CPAP pressure after automatic titration.

Evaluation of a System for Transcutaneous Long-Term Capnometry

Background: The measurement of CO₂ partial pressure (PCO₂) is of great importance. Former systems of transcutaneous capnometry combining the measurement of oxygen partial pressure (PO₂) and PCO₂ had their limitations due to skin irritations caused by the heating-up of the sensor and a short application time of 4 h. Objectives: To evaluate for the first time combined monitoring of transcutaneous PCO₂ (tcPCO₂) and oxygen saturation applying a lower temperature (sensor temperature 42°C) and a new sensor technology in healthy individuals during sleep. Methods: Twenty-nine healthy individuals [12 males, age 35.2 ± 17.0 years, body height: 170.2 ± 12.0 cm (mean ± SD), weight: 76.3 ± 15.8 kg, body mass index 26.5 ± 5.4] were monitored for more than 6 h at night with the TOSCA 500 instrument (Radiometer, Basel, Switzerland). tcPCO₂ was continuously monitored and its correlation with selective measured capillary PCO₂ values (PcapCO₂) was monitored at 0.00 and 4.00 h. Results: At 0.00 h, PcapCO₂ was 37.1 ± 5.1 mm Hg and tcPCO₂ was 43.4 ± 6.6 mm Hg (p < 0.001). At 4.00 h, PcapCO₂ was 37.0 ± 5.6 mm Hg and tcPCO₂ was 43.5 ± 5.4 mm Hg (p < 0.001). PcapCO₂ and tcPCO₂ were positively and significantly correlated (0.00 h: r = 0.5, p < 0.02 and 4.00 h: r = 0.72 and p < 0.001) at both time points. In the course of the night, there was no significant drift in the tcPCO₂ values. Conclusion: The investigated system enables stable measurement of tcPCO₂ without relevant drift in healthy individuals and does not require recalibration. tcPCO₂ is highly suitable as a measure of PcapCO₂ because the two parameters are highly correlated and there is no inconvenience to the patient.

Fiducial marker placement via conventional or electromagnetic navigation bronchoscopy (ENB): an interdisciplinary approach to the curative management of lung cancer.

Conventional and electromagnetic navigation bronchoscopy (ENB) is generally used as a diagnostic tool in suspicious pulmonary nodules. The use of this technique for the placement of fiducial markers in patients with inoperable but early‐stage lung cancer could present an innovative approach enabling risk‐reduced therapy.

Frequency and management of respiratory incidents in invasive home ventilation.

There has been a rise in the number of patients requiring long-term ventilation, both in the in-hospital and the out-of-hospital setting. Despite this, little is known about the subsequent clinical course of these patients following hospital discharge. The purpose of this study was to determine the frequency and management of respiratory incidents in patients with invasive out-of-hospital ventilation living in a nursing home allied to a weaning centre. We evaluated retrospectively the protocols that are used to monitor the patients over a period of 2 months. The average time from hospital discharge was 386 ± 330 days. Of the total 17 patients, 9 (53%) patients remained free from any respiratory incidents, while the remaining 8 (47%) patients were responsible for a total of 95 respiratory incidents. Patients that suffered respiratory incidents had been ventilated at home for an average of 194 days, while the others were receiving out-of-hospital ventilation for an average of 557 days. Desaturation (17), dyspnoea (17) and reduced general condition (10) were the most common respiratory incidents. Also, the use of an Ambu bag (bag valve mask; 17), request for a pneumologist review (12) and replacement of the tracheal cannula (7) were the most common interventions. Respiratory incidents are common in invasive home mechanical ventilation, and so home mechanical ventilation needed to be organized safely. Being allied to a weaning centre helps to organize invasive home mechanical ventilation in a safe manner over the long-term ventilation.

Comparison of Transcutaneous and Capillary Measurement of PCO2 in Hypercapnic Subjects

BACKGROUND: Measurement of PCO2 is vital in determining effective alveolar ventilation. However, obtaining capillary PCO2 by a skin prick of the earlobe is painful, and nocturnal measurements disturb sleep. End-expiratory measurement of PCO2 is also well established, but there is a low precision in predicting arterial or capillary CO2. The purpose of the study was to evaluate nocturnal measurement of noninvasive, transcutaneous PCO2 (PtcCO2) measurement in hypercapnic subjects. METHODS: In this prospective study, 31 subjects with chronic hypercapnic failure—in a stable phase of the underlying disease—and a control group of 12 healthy volunteers were included. Transcutaneous measurements were taken by the Tosca sensor (Radiometer, Copenhagen, Denmark) over a period of at least 6 h during the night. A capillary blood gas was measured at midnight and 4:00 am. RESULTS: The mean nocturnal capillary PCO2 (PcapCO2) of subjects was 50.6 ± 10.2 mm Hg. In the 31 subjects with known hypercapnic respiratory failure, the correlation between PtcCO2 and PcapCO2 at midnight was 0.86 and at 4:00 am r = 0.80. The bias of the hypercapnic subjects was d = + 4.5 with a limit(s) of agreement of 2 SD = 13.0. The process of blood sampling caused no significant change in PtcCO2. CONCLUSIONS: Our study evaluated transcutaneous capnography as a continuous nocturnal measurement in hypercapnic subjects. We found a good agreement between the methods. Because CO2 is not constant in patients with respiratory failure, but instead fluctuates, we would recommend the continuous transcutaneous measurement of PCO2 as our method of choice in the diagnosis of nocturnal hypercapnia.