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.

Background: Noninvasive positive-pressure ventilation (NPPV) using intelligent volume-assured pressure support (iVAPS) combines volume- and pressure-preset NPPV and therefore uses a variation of inspiratory positive airway pressures. Objectives: The effect of iVAPS on sleep quality in stable hypercapnic patients with chronic obstructive pulmonary disease (COPD) has not been determined. Methods: In this randomized, open-label, two-treatment, two-period, crossover study, patients were randomized to receive high-intensity (HI)-NPPV and then iVAPS or iVAPS and then HI-NPPV. Patients were studied in hospital for 2 consecutive nights, employing full polysomnography (PSG), transcutaneous partial pressure of CO₂ (PtcCO₂) monitoring, blood gas analysis and a visual analog scale (VAS)-based sleep questionnaire. After discharge, patients used HI-NPPV and iVAPS at home, each for 6 weeks. They had to answer a VAS question concerning sleep every morning, and were telephoned weekly and asked additional questions. At the end of each treatment period, they were visited at home for the determination of blood gases and treatment adherence, and to change the NPPV mode. Results: Fourteen patients were enrolled. In-hospital PSG measurements showed no difference in sleep quality between iVAPS and HI-NPPV. At home, patients reported more restful sleep during iVAPS than HI-NPPV (p = 0.04). Blood gases during spontaneous breathing at home did not differ with iVAPS and HI-NPPV, and there was a greater decrease in PtcCO₂ during iVAPS than during HI-NPPV (p = 0.003). Conclusion: Although sleep quality in hospital was not different between iVAPS and HI-NPPV, COPD patients with chronic hypercapnic respiratory failure reported a trend towards more restful sleep at home with iVAPS. In addition, nocturnal hypercapnia was effectively treated with iVAPS.

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Background: Correct measurement of PO₂ and PCO₂ is essential to establish appropriate therapy such as long-term oxygen therapy (LTOT) in patients suffering from respiratory failure. Objectives: We aimed to compare common invasive and noninvasive methods for assessing blood gas components for spot check analysis. Methods: Arterial (P_aO₂, P_aCO₂) and capillary blood gas (P_CBGO₂, P_CBGCO₂) measurements were taken consecutively in a randomized order and were compared with noninvasive measurements obtained from the transcutaneous monitoring of PO₂ and PCO₂ (P_tcO₂, P_tcCO₂, sensor-temperature 44°C). Capillary samples were taken from both arterialized earlobes, where samples of right earlobes were defined as a reference value. Pain assessment of all measurements was evaluated by each subject using the 100-mm visual analogue scale. Results: 83 patients and 17 healthy subjects were included. The mean difference between P_aO₂ and P_tcO₂ was 11.9 ± 15.0 mm Hg, with lower limits of agreement (LLA) of -17.4 mm Hg (95% confidence interval (CI) -22.5 to -12.3 mm Hg), and upper limits of agreement (ULA) of 41.1 mm Hg (95% CI 36.0-46.2 mm Hg). The comparison of P_aO₂ with P_CBGO₂ showed a mean difference of 5.6 ± 7.2 mm Hg (LLA -11.0; ULA 19.6 mm Hg). The mean difference between P_aCO₂ and P_tcCO₂ was 1.1 ± 4.9 mm Hg (LLA -8.6; ULA 10.8 mm Hg) and that between P_aCO₂ and P_CBGCO₂ was 0.7 ± 2.0 mm Hg (LLA -3.3; ULA 4.8 mm Hg). The analysis of capillary blood gases (36.2 ± 22.3 mm) was rated as more painful than the analysis of arterial blood gases (26.1 ± 20.6 mm), while transcutaneous measurement was rated as the least painful method (1.9 ± 7.4 mm; all p < 0.0001). Conclusions: The comparison of different methods for blood gas measurements showed substantial differences between capillary and arterial PO₂ and between transcutaneous and arterial PO₂. Therefore, arterial PO₂ analysis is the essential method evaluating indication for LTOT. Nevertheless, comparative analysis further indicated capillary PCO₂ as an adequate surrogate for arterial PCO₂.

BACKGROUND: High-intensity noninvasive ventilation (HI-NIV) is the most effective means of improving several physiological and clinical parameters in subjects with chronic hypercapnic COPD. Whether the newer hybrid mode using target tidal volume noninvasive ventilation (target V T NIV) provides additional benefits remains unclear. METHODS: Subjects with COPD successfully established on long-term HI-NIV were switched to target V T NIV. Optimal target V T settings according to nocturnal transcutaneous P CO 2 measurements were achieved following a randomized crossover trial using 8 mL/kg ideal body weight and 110% of individual V T during HI-NIV, respectively. The following parameters were compared at the beginning of the trial while subjects were on HI-NIV, and after 3 months on optimal target V T NIV: sleep quality by polysomnography, overnight gas exchange, subjects' tolerance, overnight pneumotachygraphic measurements during NIV, healthrelated quality of life (severe respiratory insufficiency questionnaire), exercise capacity (6-min walk test), and lung function. RESULTS: Ten of 14 subjects completed the study. There were no differences between HI-NIV and target V T NIV in any of the above-mentioned parameters. Specifically, the mean overnight transcutaneous P CO 2 was equivalent under each form of ventilation (both 45 ؎ 5 mm Hg, P ‫؍‬ .75). CONCLUSIONS: Switching subjects from well-established HI-NIV to target V T NIV shows no clinical benefits in chronic hypercapnic COPD. In particular, sleep quality, the control of nocturnal hypoventilation, daytime hypercapnia, overnight ventilation patterns, subjects' tolerance, health-related quality of life, lung function, and exercise capability were all similar in subjects who underwent HI-NIV and target V T NIV. Nevertheless, target V T NIV might offer some physiological advantages in breathing pattern and might be beneficial in some individual patients. (German Clinical Trials Register [www.drks.de] Registration DRKS00000450.)

BACKGROUND: When supplemental oxygen is added to noninvasive ventilation using a non-ICU ventilator, it is usually introduced with a preset flow into the circuit near the ventilator; however, the impact of different CO 2 exhalation systems and leaks on the actual F IO 2 and gas exchange has not been elucidated. METHODS: In a randomized, open-label, 4-treatment (2-by-2), 4-period crossover design, 4 daytime measurements (60 min each) were performed in 20 subjects receiving home mechanical noninvasive ventilation plus supplemental oxygen (> 2 L/min) inserted near the ventilator: active valve circuit or leak port circuit with or without artificial leakage (4 mm inner diameter). Oxygen concentration near the ventilator, oxygen concentration at the mask, and blood gases were measured. RESULTS: Overall, oxygen concentration at the mask (29 ؎ 5%) was lower than oxygen concentration at the ventilator (34 ؎ 4%), with a mean difference of 5.1% (95% CI 4.2-5.9%, P < .001)%. With the leak port circuit, oxygen concentration at the mask decreased by 3.2% (95% CI 2.6 to 3.9%, P < .001), compared to the active valve circuit. When artificial leakage was introduced into the circuit, oxygen concentration at the mask decreased by 5.7% (95% CI 5.1 to 6.4%, P < .001)%, P aO 2 by 10.4 mm Hg (95% CI 3.1 to 17.7 mm Hg, P ‫؍‬ .006), and P aCO 2 increased by 1.8 mm Hg (95% CI 0.5 to 3.1 mm Hg, P ‫؍‬ .008). CONCLUSIONS: The use of a leak port circuit and the occurrence of leak around the interface significantly reduced oxygen concentration at the mask and negatively impacted gas exchange in subjects receiving home noninvasive ventilation and supplemental oxygen. (German Clinical Trials Registry, www.drks.de, DRKS00000449).

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Background: Pulmonary rehabilitation (PR) has a positive impact on functional status and quality of life in patients with interstitial lung disease (ILD). Objectives: This study investigated the effects of PR in hypercapnic ILD patients receiving nighttime noninvasive positive pressure ventilation (NPPV). Methods: Consecutive ILD patients referred to a specialized inpatient PR center were included. All participated in a PR program. Those with hypercapnia received NPPV (NPPV group; n = 29); the remaining patients served as comparison group (n = 319). Results: PR improved the 6-min walk distance by 64.4 ± 67.1 m versus baseline (p < 0.0001) in NPPV patients and by 43.2 ± 55.1 m (p < 0.0001) in the comparison group (difference 21.1 m, 95% confidence interval 0.5-41.8; p = 0.045). There was no change in total lung capacity during PR in NPPV recipients or the comparison group. Forced vital capacity significantly increased from baseline in the comparison, but not the NPPV group. NPPV recipients were significantly more likely than the comparison group to have improved dyspnea during PR (p = 0.049). There was no improvement in the 36-item Short Form (SF-36) physical component score in the NPPV group after PR, but there was in the comparison group. PR improved the SF-36 mental component score versus baseline in both groups. Conclusion: An individually tailored PR plus nighttime NPPV appears feasible in hypercapnic ILD patients and significantly improves exercise capacity and quality of life.