- Email: [email protected]
APAP or CPAP: Who benefits?
Sleep Medicine 8 (2007) 691–692 www.elsevier.com/locate/sleep
Editorial
APAP or CPAP: Who benefits? In the recent decade, automatic continuous positive airway pressure (APAP) has generally been accepted as an alternative to constant positive airway pressure (CPAP) in the treatment of the obstructive sleep apnea syndrome (OSAS) [1,2]. Prescriptions for automatic devices vary in a wide range between 10% and 40% in different countries, often depending more on the legal regulations of reimbursement than on medical aspects. However, this gives the idea that sleep specialists do not uniformly estimate the relevance of APAP and that clear evidence-based guidelines for its use are still missing. Additionally, the tentativeness in the use of automatic CPAP may be boosted because the crucial discrimination between automatic titration and automatic treatment is often neglected in scientific literature. The options for auto-adjusting CPAP are based on different algorithms and can result in essential differences in use. Algorithms for automatic titration are intended to find one single optimal pressure level for continuous treatment with a constant CPAP device at home. As under manual titration, the pressure level should be as low as possible but must completely suppress the respiratory disturbances in any situation throughout the course. On the contrary, algorithms for automatic treatment are not intended to find a constant pressure level but must continuously adapt a treatment pressure every night, in every situation to the actual level of obstruction. The aim is to reduce the mean treatment pressure and to improve patients’ acceptance [3]. The reports that read out of the APAP devices describe the pressure profile of a single night or longer time periods. They mostly include the maximum pressure (Pmax), the mean pressure (Pmean) and the 95th percentile (P95). The P95 read-out from a titration device can be recommended for constant CPAP [4]. On the other hand, algorithms designed for automatic treatment set the pressure to the lowest possible level throughout long periods of the night, resulting in significantly lower P95 and Pmean, compared to titration algorithms. Automatic titration increases the treatment pressure step by step but rarely lowers it. Therefore, a higher variability of the treatment pressure results from
1389-9457/$ - see front matter Ó 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.sleep.2007.05.002
treatment devices. Using treatment devices for titration may lead to substantial misinterpretations, and using titration algorithms for long-term treatment may result in higher CPAP levels [5,6]. In this issue of Sleep Medicine, Meurice et al. present the results of a multicenter, randomized multi-cohort study on the effects of four automatic CPAP devices compared with constant CPAP [7]. This study is noteworthy for several reasons. First of all, the authors clearly used the automatic CPAP devices for treatment purposes only. The pressure in the constant CPAP group was titrated manually. Second, the authors studied different options over a period of 6 months, which is longer than in most previous studies on autoCPAP. Moreover, CPAP titration and APAP initiation were done under polysomnographic control, which is the only way to optimize the treatment right from the beginning. Several previous studies have focused on economic aspects, trying to show that APAP titration or treatment is effective without polysomnography or personal attention. Most of these studies did not take into account the costs of additional titration nights and of non-productive time at work due to insufficient control of sleep apnea. Using auto-titration under unattended polysomnography might result in underestimation of the necessary pressure because relevant upper airway obstructions indicated by flattening or respiratory arousals might be overseen, or might result in overtreatment because breathing irregularities while awake or central disturbances might lead to incorrect pressure increases [8,9]. APAP titration allows the titration procedure to be standardized, making it independent of different levels of experience and concentration, but it does not make personal attention unnecessary. APAP treatment substantially reduces the pressure level. These advantages are independent of economic aspects. Devices for automatic CPAP treatment were built with the intention of improving patient compliance and indeed there are some findings in previous studies which seem to prove this hypothesis [3]. However, Meurice et al. failed to show any benefit in compliance, self-assessment or suppression of respiratory disturbances compared to
692
Editorial / Sleep Medicine 8 (2007) 691–692
constant CPAP. Some limitations of the study should be highlighted: The study included only patients with moderate to severe sleep apnea syndrome. Therefore, the results cannot readily be translated to patients with comorbidities or with accompanying central disturbances. Moreover, patients with mild sleep apnea/hypopnea show the worst compliance, although treatment might be indicated due to the cardiovascular risk. It seems clinically relevant to study these groups further as they represent common problems in the daily work in sleep laboratories. Moreover, as in many prospective trials, compliance was quite high in all subgroups and may have been influenced by the study design which consisted of several follow-up visits in the sleep laboratory or at the patients’ homes. These excellent conditions may have diminished differences in compliance. Therefore, we should translate the results, with great caution, to real-life practice in communities with less intensive follow-up procedures. Nevertheless, it can be concluded that neither autoCPAP nor constant CPAP may be recommended as the one and only treatment option for OSAS. But who benefits from APAP treatment? The paper by Meurice et al. does not answer this question due to statistical aspects. However, it confirmed a very important finding. The treatment pressure under APAP showed a wide variability throughout the whole study period. This confirms that the variability of upper airway obstructions is not the exception but the rule in patients with OSAS [3]. The idea of constant CPAP is to define one single pressure level for optimal treatment in any situation throughout the whole treatment course. In view of the wide variability of upper airway obstruction throughout the night by these findings this approach seems quite artificial [10]. Nevertheless, it works, but it implies overtreatment for large amounts of time. APAP treatment may be advantageous for difficult-to-treat patients, for patients who need high pressure or for those with relevant pressure differences according to sleep stages or body position [11–13]. The paper by Meurice and colleagues once again confirms that we must individualize CPAP treatment.
Practice parameters for the use of auto-titrating continuous positive airway pressure devices for titrating pressures and treating adult patients with obstructive sleep apnea syndrome. An American Academy of Sleep Medicine report. Sleep 2002;25(2):143–7. [3] Randerath WJ. Automatic positive airway pressure titration and treatment. In: Randerath WJ, Sanner B, Somers V, editors. Sleep apnea: current diagnosis and treatment. progress in respiratory research, Vol. 35. Basel, New York: Karger; 2006. p. 137–44. [4] Teschler H, Berthon-Jones M, Thompson AB, Henkel A, Henry J, Konietzko N. Automated continuous positive airway pressure titration for obstructive sleep apnea syndrome. Am J Respir Crit Care Med 1996;154:734–7404. [5] Kessler R, Weitzenblum E, Chaouat A, Iamandi C, Alliotte T. Evaluation of unattended automated titration to determine therapeutic continuous positive airway pressure in patients with obstructive sleep apnea. Chest 2003;123(3):704–10. [6] Pevernagie DA, Proot PM, Hertegonne KB, Neyens MC, Hoornaert KP, Pauwels RA. Efficacy of flow- vs impedanceguided autoadjustable continuous positive airway pressure: a randomized cross-over trial. Chest 2004;126(1):25–30. [7] Meurice J-C, Cornette A, Philip-Joet F, Escorrou P, Ingrand P, Veale D. Evaluation of autoCPAP devices in home treatment of sleep Apnoea/hypopnoea syndrome. Sleep Med 2007;8:695–703. [8] Juhasz J, Schillen J, Urbigkeit A, Ploch T, Penzel T, Peter JH. Unattended continuous positive airway pressure titration. Clinical relevance and cardiorespiratory hazards of the method. Am J Respir Crit Care Med 1996;154(2 Pt. 1):359–65. [9] Marrone O, Insalaco G, Salvaggio A, Bonsignore G. Role of different nocturnal monitorings in the evaluation of CPAP titration by autoCPAP devices. Respir Med 2005;99(3):313–20. [10] Sharma S, Wali S, Pouliot Z, Peters M, Neufeld H, Kryger M. Treatment of obstructive sleep apnea with a self-titrating continuous positive airway pressure (CPAP) system. Sleep 1996;19(6): 497–501. [11] Ficker JH, Fuchs FS, Wiest GH, Asshoff G, Schmelzer AH, Hahn EG. An auto-continuous positive airway pressure device controlled exclusively by the forced oscillation technique. Eur Respir J 2000;16:910–4. [12] Randerath W, Galetke W, Ru¨hle KH. Auto-adjusting CPAP based on impedance versus bilevel pressure in difficult-to-treat sleep apnea syndrome: a prospective randomized crossover study. Med Sci Monit 2003;9:353–8. [13] Massie CA, McArdle N, Hart RW, Schmidt-Nowara WW, Lankford A, Hudgel DW, Gordon N, Douglas NJ. Comparison between automatic and fixed positive airway pressure therapy in the home. Am J Respir Crit Care Med 2003;167(1):20–3.
Winfried J. Randerath * Institute of Pneumology at the University Witten/ Herdecke, Clinic of Pneumology and Allergology, Center of Sleep Medicine and Ventilatory Care, Bethanien Hospital, Aufderhoeher Strasse 169–175, 42699 Solingen, Germany E-mail address: [email protected]
References [1] Berry RB, Parish JM, Hartse KM. The use of auto-titrating continuous positive airway pressure for treatment of adult obstructive sleep apnea. An American Academy of Sleep Medicine review. Sleep 2002;25:148–73. [2] Littner M, Hirshkowitz M, Davila D, Anderson WM, Kushida CA, Woodson BT, Johnson SF, Merrill SW. Standards of Practice Committee of the American Academy of Sleep Medicine.
Received 4 May 2007; accepted 22 May 2007 Available online 20 July 2007
*
Tel.: +49 212 636000; fax: +49 212 636005.
Editorial
APAP or CPAP: Who benefits? In the recent decade, automatic continuous positive airway pressure (APAP) has generally been accepted as an alternative to constant positive airway pressure (CPAP) in the treatment of the obstructive sleep apnea syndrome (OSAS) [1,2]. Prescriptions for automatic devices vary in a wide range between 10% and 40% in different countries, often depending more on the legal regulations of reimbursement than on medical aspects. However, this gives the idea that sleep specialists do not uniformly estimate the relevance of APAP and that clear evidence-based guidelines for its use are still missing. Additionally, the tentativeness in the use of automatic CPAP may be boosted because the crucial discrimination between automatic titration and automatic treatment is often neglected in scientific literature. The options for auto-adjusting CPAP are based on different algorithms and can result in essential differences in use. Algorithms for automatic titration are intended to find one single optimal pressure level for continuous treatment with a constant CPAP device at home. As under manual titration, the pressure level should be as low as possible but must completely suppress the respiratory disturbances in any situation throughout the course. On the contrary, algorithms for automatic treatment are not intended to find a constant pressure level but must continuously adapt a treatment pressure every night, in every situation to the actual level of obstruction. The aim is to reduce the mean treatment pressure and to improve patients’ acceptance [3]. The reports that read out of the APAP devices describe the pressure profile of a single night or longer time periods. They mostly include the maximum pressure (Pmax), the mean pressure (Pmean) and the 95th percentile (P95). The P95 read-out from a titration device can be recommended for constant CPAP [4]. On the other hand, algorithms designed for automatic treatment set the pressure to the lowest possible level throughout long periods of the night, resulting in significantly lower P95 and Pmean, compared to titration algorithms. Automatic titration increases the treatment pressure step by step but rarely lowers it. Therefore, a higher variability of the treatment pressure results from
1389-9457/$ - see front matter Ó 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.sleep.2007.05.002
treatment devices. Using treatment devices for titration may lead to substantial misinterpretations, and using titration algorithms for long-term treatment may result in higher CPAP levels [5,6]. In this issue of Sleep Medicine, Meurice et al. present the results of a multicenter, randomized multi-cohort study on the effects of four automatic CPAP devices compared with constant CPAP [7]. This study is noteworthy for several reasons. First of all, the authors clearly used the automatic CPAP devices for treatment purposes only. The pressure in the constant CPAP group was titrated manually. Second, the authors studied different options over a period of 6 months, which is longer than in most previous studies on autoCPAP. Moreover, CPAP titration and APAP initiation were done under polysomnographic control, which is the only way to optimize the treatment right from the beginning. Several previous studies have focused on economic aspects, trying to show that APAP titration or treatment is effective without polysomnography or personal attention. Most of these studies did not take into account the costs of additional titration nights and of non-productive time at work due to insufficient control of sleep apnea. Using auto-titration under unattended polysomnography might result in underestimation of the necessary pressure because relevant upper airway obstructions indicated by flattening or respiratory arousals might be overseen, or might result in overtreatment because breathing irregularities while awake or central disturbances might lead to incorrect pressure increases [8,9]. APAP titration allows the titration procedure to be standardized, making it independent of different levels of experience and concentration, but it does not make personal attention unnecessary. APAP treatment substantially reduces the pressure level. These advantages are independent of economic aspects. Devices for automatic CPAP treatment were built with the intention of improving patient compliance and indeed there are some findings in previous studies which seem to prove this hypothesis [3]. However, Meurice et al. failed to show any benefit in compliance, self-assessment or suppression of respiratory disturbances compared to
692
Editorial / Sleep Medicine 8 (2007) 691–692
constant CPAP. Some limitations of the study should be highlighted: The study included only patients with moderate to severe sleep apnea syndrome. Therefore, the results cannot readily be translated to patients with comorbidities or with accompanying central disturbances. Moreover, patients with mild sleep apnea/hypopnea show the worst compliance, although treatment might be indicated due to the cardiovascular risk. It seems clinically relevant to study these groups further as they represent common problems in the daily work in sleep laboratories. Moreover, as in many prospective trials, compliance was quite high in all subgroups and may have been influenced by the study design which consisted of several follow-up visits in the sleep laboratory or at the patients’ homes. These excellent conditions may have diminished differences in compliance. Therefore, we should translate the results, with great caution, to real-life practice in communities with less intensive follow-up procedures. Nevertheless, it can be concluded that neither autoCPAP nor constant CPAP may be recommended as the one and only treatment option for OSAS. But who benefits from APAP treatment? The paper by Meurice et al. does not answer this question due to statistical aspects. However, it confirmed a very important finding. The treatment pressure under APAP showed a wide variability throughout the whole study period. This confirms that the variability of upper airway obstructions is not the exception but the rule in patients with OSAS [3]. The idea of constant CPAP is to define one single pressure level for optimal treatment in any situation throughout the whole treatment course. In view of the wide variability of upper airway obstruction throughout the night by these findings this approach seems quite artificial [10]. Nevertheless, it works, but it implies overtreatment for large amounts of time. APAP treatment may be advantageous for difficult-to-treat patients, for patients who need high pressure or for those with relevant pressure differences according to sleep stages or body position [11–13]. The paper by Meurice and colleagues once again confirms that we must individualize CPAP treatment.
Practice parameters for the use of auto-titrating continuous positive airway pressure devices for titrating pressures and treating adult patients with obstructive sleep apnea syndrome. An American Academy of Sleep Medicine report. Sleep 2002;25(2):143–7. [3] Randerath WJ. Automatic positive airway pressure titration and treatment. In: Randerath WJ, Sanner B, Somers V, editors. Sleep apnea: current diagnosis and treatment. progress in respiratory research, Vol. 35. Basel, New York: Karger; 2006. p. 137–44. [4] Teschler H, Berthon-Jones M, Thompson AB, Henkel A, Henry J, Konietzko N. Automated continuous positive airway pressure titration for obstructive sleep apnea syndrome. Am J Respir Crit Care Med 1996;154:734–7404. [5] Kessler R, Weitzenblum E, Chaouat A, Iamandi C, Alliotte T. Evaluation of unattended automated titration to determine therapeutic continuous positive airway pressure in patients with obstructive sleep apnea. Chest 2003;123(3):704–10. [6] Pevernagie DA, Proot PM, Hertegonne KB, Neyens MC, Hoornaert KP, Pauwels RA. Efficacy of flow- vs impedanceguided autoadjustable continuous positive airway pressure: a randomized cross-over trial. Chest 2004;126(1):25–30. [7] Meurice J-C, Cornette A, Philip-Joet F, Escorrou P, Ingrand P, Veale D. Evaluation of autoCPAP devices in home treatment of sleep Apnoea/hypopnoea syndrome. Sleep Med 2007;8:695–703. [8] Juhasz J, Schillen J, Urbigkeit A, Ploch T, Penzel T, Peter JH. Unattended continuous positive airway pressure titration. Clinical relevance and cardiorespiratory hazards of the method. Am J Respir Crit Care Med 1996;154(2 Pt. 1):359–65. [9] Marrone O, Insalaco G, Salvaggio A, Bonsignore G. Role of different nocturnal monitorings in the evaluation of CPAP titration by autoCPAP devices. Respir Med 2005;99(3):313–20. [10] Sharma S, Wali S, Pouliot Z, Peters M, Neufeld H, Kryger M. Treatment of obstructive sleep apnea with a self-titrating continuous positive airway pressure (CPAP) system. Sleep 1996;19(6): 497–501. [11] Ficker JH, Fuchs FS, Wiest GH, Asshoff G, Schmelzer AH, Hahn EG. An auto-continuous positive airway pressure device controlled exclusively by the forced oscillation technique. Eur Respir J 2000;16:910–4. [12] Randerath W, Galetke W, Ru¨hle KH. Auto-adjusting CPAP based on impedance versus bilevel pressure in difficult-to-treat sleep apnea syndrome: a prospective randomized crossover study. Med Sci Monit 2003;9:353–8. [13] Massie CA, McArdle N, Hart RW, Schmidt-Nowara WW, Lankford A, Hudgel DW, Gordon N, Douglas NJ. Comparison between automatic and fixed positive airway pressure therapy in the home. Am J Respir Crit Care Med 2003;167(1):20–3.
Winfried J. Randerath * Institute of Pneumology at the University Witten/ Herdecke, Clinic of Pneumology and Allergology, Center of Sleep Medicine and Ventilatory Care, Bethanien Hospital, Aufderhoeher Strasse 169–175, 42699 Solingen, Germany E-mail address: [email protected]
References [1] Berry RB, Parish JM, Hartse KM. The use of auto-titrating continuous positive airway pressure for treatment of adult obstructive sleep apnea. An American Academy of Sleep Medicine review. Sleep 2002;25:148–73. [2] Littner M, Hirshkowitz M, Davila D, Anderson WM, Kushida CA, Woodson BT, Johnson SF, Merrill SW. Standards of Practice Committee of the American Academy of Sleep Medicine.
Received 4 May 2007; accepted 22 May 2007 Available online 20 July 2007
*
Tel.: +49 212 636000; fax: +49 212 636005.