American Journal of Therapeutics 0, 1–5 (2015)
Comparison of Efficacy and Tolerance of Automatic Continuous Positive Airway Pressure Devices With the Optimum Continuous Positive Airway Pressure George Tommi, MD,1 Wilbert S. Aronow, MD,2* John C. Sheehan, MD,1 Matthew T. McCleay, MD,1 and Patrick G. Meyers, MD1
Patients diagnosed with obstructive sleep apnea syndrome were randomly placed on automatic continuous positive airway pressure (ACPAP) for 2 hours followed by manual titration for the rest of the night. One hundred sixty-one patients entered the study, with at least 50 patients titrated with each of 3 ACPAP devices. The optimum continuous positive airway pressure (CPAP) was defined as the lowest pressure with an apnea–hypoxia index of #5/hr, which ranged from 4 cm to 18 cm. Success with ACPAP was approximately 60%–80% when the optimum CPAP was 4–6 cm but fell to below 30% if the optimum CPAP was $8 cm (P 5 0.001). Average ACPAP ranged from 2 to 10 cm below the optimum level if the optimum CPAP was $8 cm. Patients who responded to a low CPAP but deteriorated on higher pressures failed to respond to any of the automatic devices. We recommend that CPAP titration be performed manually before initiation of ACPAP in patients with obstructive sleep apnea. The basal pressure for ACPAP should be the optimum pressure obtained by manual titration. Limits on the upper level of ACPAP may be necessary for patients who deteriorate on higher positive pressures. Keywords: continuous positive airway pressure, obstructive sleep apnea, apnea–hypoxia index
INTRODUCTION The prevalence of obstructive sleep apnea (OSA) in the general population is estimated to be 24% in men and 9% in women.1 Serious cardiovascular and central nervous system complications with increased morbidity and mortality associated with OSA warrant medical intervention with continuous positive airway pressure (CPAP) being the most successful
1
Midwest Pulmonary and Critical Care, Creighton University, Omaha, NE; and 2Division of Cardiology, Department of Medicine, Westchester Medical Center, New York Medical College, Valhalla, NY. The authors have no conflicts of interest to declare. *Address for correspondence: Division of Cardiology, Department of Medicine, New York Medical College, Macy Pavilion, Room 138, Valhalla, NY 10595. E-mail: [email protected]
noninvasive therapy for this disorder.2–4 Automatic continuous positive airway pressure (ACPAP) devices have been introduced in the treatment regimen because problems with compliance and intolerance to CPAP occur in over 30% of patients treated with CPAP.5 Moreover, the cost of an overnight polysomnogram (PSG) and the need for a possible second night CPAP titration have made the use of these automatic devices more common.6 Authors have suggested that the optimum CPAP tends to be higher in patients with severe OSA, high body mass index, or large neck circumference, although the exact correlation is unclear. The optimum CPAP does not always correlate with the severity of the apnea–hypopnea index (AHI), and patients with severe OSA may respond to a low optimum CPAP.7,8 This study investigated whether efficacy and tolerance to ACPAP would be the same as manual titration if the optimum CPAP was $6 cm.
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www.americantherapeutics.com
Copyright Ó 2015 Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited.
Tommi et al
2
METHODS A prospective double-blind study was performed comparing 3 different ACPAP devices that are commonly used (ResMed, Fisher Paykel, and Respironics) with various optimum CPAPs. Inclusion criteria were patients older than 18 years with an AHI above 5/hr on an overnight PSG who agreed to an overnight PSG for manual CPAP/ACPAP titration and who agreed to participate in the study. Patients were excluded if they were unable to tolerate CPAP, were claustrophobic, did not respond to CPAP titration, failed manual titration (unable to get the AHI below 5/hr on manual titration), refused to participate in the study, or had acute medical problems. A second overnight PSG for CPAP titration was performed within 2 weeks, and each month a different device was used. The technician randomly chose one of the 3 ACPAP devices until at least 50 patients were studied. ACPAP was initiated randomly in the first or second half of the night for at least 2 hours. Using the same CPAP device, manual titration was initiated from 4 cm to 12 cm for 30–45 minutes in each pressure. If apnea or hyponea persisted at 12 cm, titration up to 18 cm was performed. Airflow was measured using thermistors at the nose and mouth, and respiratory and abdominal effort was measured using respiratory and abdominal piezo belts. Obstructive apnea was defined as no airflow for at least 10 seconds associated with respiratory and/or abdominal wall movements. Hypopnea was defined as decreased airflow by at least 30% for at least 10 seconds associated with a 4% desaturation or a 50% decrease in airflow for at least 10 seconds associated with an arousal. The optimum CPAP was defined as the lowest pressure required to reduce the AHI at or below 5/hr. Success rates were compared between groups using an exact Pearson x2 test. Mean age was compared between successes and failures using a Mann–Whitney test. The distribution of gender was approximately balanced across the 3 groups with 38%, 33%, and 33% females in the Fisher Paykel, ResMed, and Respironics groups, respectively. Age was also similar among the groups with mean ages of 54.4 years, 57.4 years, and 58.6 years for the Fisher Paykel, ResMed, and Respironics groups, respectively. Success was defined as an AHI at or below 5/hr. There was a significant difference in the success rates by device. The distribution of success by device was: Fisher Paykel, 56%; ResMed, 27%; and Respironics, 43% (P , 0.001). For all devices combined, the proportion of successes was higher for the ,8 cm pressure group compared with the $8 cm pressure group (56% vs. 16%, P , 0.001, Fisher exact American Journal of Therapeutics (2015) 0(0)
test). The success rate for the ,8 cm pressure group compared with the $8 cm pressure group for Fisher Paykel was 79% versus 24% (P 5 0.001, Fisher exact test), for ResMed was 34% versus 8% (P 5 0.08), and for Respironics 62% versus 15% (P 5 0.001).
RESULTS One hundred sixty-one patients were evaluated and entered the study. Male to female ratio was 7:3, and ages ranged from 25 to 90 years with a mean age of 56.8 years. The initial AHI ranged from 6 to 80 an hour, and the optimum CPAP levels ranged from 4 cm to 18 cm. Fifty-three patients were placed on ResMed, 54 patients on Respironics, and 54 patients on Fisher Pakyel. Six patients titrated on bilevel positive airway pressure, and 14 patients who failed to respond to CPAP were discontinued from the study. When the optimum CPAP was 4 or 6 cm, efficacy for the 3 devices ranged between 60% and 80%, Fisher Pakyel being the most effective. Efficacy to the 3 devices was less than 30% when the optimum CPAP was $8 cm. The average ACPAP correlated less than 33% with Fisher Pakyel and ResMed but was approximately 50% with Respironics when the optimum CPAP was $8 cm (Tables 1 and 2). Six patients who responded well to a lower CPAP but deteriorated on a higher CPAP failed to respond to any of the ACPAP devices. One patient on ResMed, 3 patients on Fischer Paykel, and 7 patients on Respironics did not tolerate ACPAP titration and were included in the failures. There was a significant difference in the success rates by device. The distribution of success by device was Fisher Paykel, 56%; ResMed, 27%; and Respironics, 43% (P , 0.001). For all devices combined, the proportion of successes was higher for the ,8 cm pressure group compared with the $8 cm pressure group (56% vs. 16%, P , 0.001, Fisher exact test). The success rate for the ,8 cm pressure group compared with the $8 cm pressure group for Fisher Paykel was 79% versus 24% (P 5 0.001, Fisher exact test), for ResMed 34% versus 8% (P 5 0.08), and for Respironics 62% versus 15% (P 5 0.001).
DISCUSSION The severity of AHI is known to vary nightly and tends to be more severe in the supine position, with rapid eye movement sleep and with use of sedatives, hypnotics, and alcohol.9,10 ACPAP devices have been used in the management of OSA over the last few years, and these devices are supposed to increase or decrease the pressure depending on the severity of the www.americantherapeutics.com
Copyright Ó 2015 Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited.
Optimum CPAP
3
Table 1. Average ACPAP compared with various optimal CPAP with 3 ACPAP devices. opCPAP (4/6 cm) ACPAP device average pressure ResMed 36 patients 16 patients Respironics 32 patients 22 patients Fisher Paykel 31 patients 22 patients
opCPAP ($8 cm)
Discard
.2 cm
.4 cm
.6 cm
,2 cm
,4 cm
8 —
1 —
2 —
— 8
— 4 (1 , 10 cm)
1
— 4
5 —
2 —
6 —
— 4
— 1
1 5
1 2
9 —
2 —
7 —
— 9
— 8 (2 , 9 cm)
3
3 5
Sleep Efficiency ,25%
opCPAP, optimal CPAP.
AHI and snoring. The downside to our method of manual CPAP titration is that rapid eye movement sleep and the supine position do not occur at each pressure. However, the response to each pressure is easily documented with our titration, and the optimum pressure determined by other methods could vary significantly depending on the PSG technician performing the study. This method would also identify patients who deteriorate on higher pressures of CPAP. All patients were followed for at least 6 months and, in this study, no pressure changes were made. Several ACPAP devices are currently in use, and their mechanism of action defers from each other.11–15 The ResMed Autoset device detects respiratory events using a multiple breath moving average technique and responds to any airway changes, such as flow limitation, apneas, and snoring. This device postulates that flow limitation precedes snoring and apneas and that the pressure is increased in these situations. These devices also are supposed to calculate the pressure needed based on the severity of the event. The Respironics autoset device analyzes changes in flatness, roundness, peak, and
shape of the flow. It also has the capability to detect vibrations from snoring and adjusts the pressure. This device has a nonresponsive apnea/hyponea logic that is supposed to reduce the pressure to manage respiratory events that are nonresponsive to high CPAP. The Fisher Paykel automatic set device monitors flow in a 5-breath moving window and responds to flow limitation, apneas, and hyponeas. The “Senswake” mode in these devices detects the pattern of irregular breathing that occurs at the transition from sleep to wake and reduces the pressure until the minimum or sensawake pressure is reached, which takes until 2 minutes. These automatic devices have been reported to be as effective as manual titration, and some investigators have suggested that patients be initiated on ACPAP without manual titration. However, most of these studies enrolled small number of patients, and all of them compared the efficacy with the severity of AHI but not to the optimum CPAP.10,12 In studies where the ACPAP was allowed to titrate from 4 cm to 16 cm, the average CPAP was 2–6 cm below the optimum CPAP pressure and most of these patients
Table 2. Comparing success by pressure groups with ACPAP devices and various optimum CPAPs. Device ResMed Fisher Paykel Respironics All devices combined
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Pressure (cm) ,8 $8 ,8 $8 ,8 $8 ,8 $8
Success, n (%) 12 1 19 4 18 3 49 8
(34) (8) (79) (24) (62) (15) (56) (16)
Failure, n (%) 23 12 5 13 11 17 39 42
(66) (92) (21) (76) (38) (85) (44) (84)
P 0.08 0.001 0.001 ,0.001
American Journal of Therapeutics (2015) 0(0)
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4
demonstrated an increase in excessive daytime sleepiness.16–18 Condos et al showed that a reduction in constant CPAP pressure of 2 mbar was associated with partial collapse of the upper airways.19,20 Subtherapeutic pressures compared with therapeutic CPAP pressures show failure to improve excessive daytime sleepiness, hypertension, daytime PaO2 levels, and cognitive function in OSA patients.21,22 Efficacy varies significantly with different ACPAP devices tested, and automatic titration should not be performed at home.11,15,23 Patients who do not snore or had upperairway surgery fail to respond to automatic devices dependent on vibration only.12 Devices monitoring snoring, flow, or impedance (forced-oscillation technique) fail adequately to titrate to respiratory events if there are mask or mouth leaks. Rapid alterations with awake and sleep or occurrence of central apneas limit the efficacy of these automatic devices resulting in prolonged periods of high pressure causing more air leaks and sleep fragmentation. These ACPAP devices are also not recommended for patients with hypoventilation obesity syndrome, severe chronic obstructive pulmonary disease, asthma, and heart failure.10,12,14,24,25 Patients who deteriorate on higher CPAP should not be placed on ACPAP because there is a risk of these devices delivering very high pressures. In conclusion, we found that ACPAP fails to show efficacy in patients with OSA if the optimum CPAP is $8 cm. We recommend from our data that the baseline pressure for automatic devices be the optimum pressure obtained by manual titration. The maximum pressure for these automatic devices should be limited in patients who deteriorate on higher CPAP levels.
ACKNOWLEDGMENTS The authors thank Jody Woodard, Jody Blakely, and Shannon Wilson for collecting and recording the data. The authors thank the sleep technologists at Midwest Sleep Laboratory for randomization and monitoring the protocol. The authors thank Jane Mezza, Professor and Chair, Department of Biostatistics at the University of Omaha Medical Center, for her invaluable help in analyzing the data.
REFERENCES 1. Young T, Palta M, Dempsey J, et al. The occurrence of sleep-disordered breathing among middle-aged adults. N Engl J Med. 1993;328:1230–1235. American Journal of Therapeutics (2015) 0(0)
Tommi et al 2. Shahar E, Whitney CW, Redline S, et al. Sleep-disordered breathing and cardiovascular disease: cross-sectional results of the Sleep Heart Health Study. Am J Respir Crit Care Med. 2001;163:19–25. 3. Doherty LS, Kiely JL, Swan V, et al. Long-term effects of nasal CPAP therapy on cardiovascular outcomes in the sleep apnea syndrome. Chest. 2005;127: 2076–2084. 4. Sullivan CE, Issa FG, Berthon Jones M, et al. Reversal of obstructive sleep apnea by continuous positive airway pressure applied through the nares. Lancet. 1981;i: 862–865. 5. American Thoracic Society Official Statement. Indications and standards for use of nasal continuous positive airway pressure (CPAP) in sleep apnea syndrome. Am J Respir Crit Care Med. 1994;50:1738–1745. 6. Ayas NT, Patel SR, Malhotra A, et al. Auto titrating versus continuous positive airway pressure for the treatment of obstructive sleep apnea: results of a meta-anaylsis. Sleep. 2004;15;249–253. 7. Rowley JA, Tarbichi AG, Badr MS. The use of predicted CPAP equation improves CPAP titration success. Sleep Breath. 2005;9:26–32. 8. Lin IF, Chuang ML, Liao YF, et al. Predicting effective continuous positive airway pressure in Taiwanese patients with obstructive sleep apnea syndrome. J Formos Med Assoc. 2003;102:215–221. 9. Oksenberg A, Silverberg DS, Arons E, et al. The sleep supine position has a major effect on optimal nasal continuous positive airway pressure: relationship with rapid eye movements and non-rapid eye movements sleep, body mass index, respiratory disturbance index, and age. Chest. 1999;116:1000–1006. 10. Levy P, Pepin JL. Autoadjusting continuous positive airway pressure: what can we expect? Am J Respir Crit Care Med. 2001;163:1295–1296. 11. Stammnitz A, Jerrentrup A, Penzel T, et al. Automatic CPAP titration with different self-setting devices in patients with obstructive sleep apnoea. Eur Respir J. 2004;2: 273–278. 12. 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;25:148–173. 13. Pevernagie DA, Proot PM, Hertegonne KB, et al. Efficacy of flow-vs impedance-guided autoadjustable continuous positive airway pressure: a randomized cross over trial. Chest. 2004;126:25–30. 14. Morgenthaler TI, Aurora RN, Brown T, et al. Practice parameters for the use of autotitrating continuous positive airway pressure devices for titrating pressures and treating adult patients with obstructive sleep apnea syndrome: an update for 2007. An American Academy of Sleep Medicine report. Sleep. 2008;31:141–147. 15. Nolan GM, Ryan S, O’Connor TM, et al. Comparison of three auto-adjusting positive pressure devices in patients with sleep apnoea. Eur Respir J. 2006;28: 159–164. www.americantherapeutics.com
Copyright Ó 2015 Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited.
Optimum CPAP 16. Hudgel DW, Fung C. A long-term randomized, crossover comparison of autotitrating and standard nasal continuous airway pressure. Sleep. 2000;23:645–648. 17. Boudewyne A, Grillier-Lanoir V, Willemen MJ, et al. Two months follow up of auto-CPAP treatment in patients with obstructive sleep apnoea. Thorax. 1999;54:147–149. 18. Teschler H, Wessendorf TE, Farhat AA, et al. Two months auto-adjusting versus con- ventional nCPAP for obstructive sleep apnoea syndrome. Eur Respir J. 2000;15:990–995. 19. Condos R, Norman RG, Krishnasamy I, et al. Flow limitation as a noninvasive assessment of residual upperairway pressure therapy of obstructive sleep apnea. Am J Respir Crit Care Med. 1994;150:475–480. 20. Montserrat JM, Ballester E, Olivi H, et al. Time-course of stepwise CPAP titration. Am J Respir Crit Care Med. 1995; 152:1854–1859. 21. Jenkinson C, Davies RJ, Mullins R, et al. Comparison of therapeutic and subtherapeutic nasal continuous positive
www.americantherapeutics.com
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22.
23.
24.
25.
airway pressure for obstructive sleep apnoea: a randomised prospective parallel trial. Lancet. 1999;353: 2100–2105. Pepperell JC, Ramdassingh-Dow S, Crosthwaite N, et al. Ambulatory blood pressure after therapeutic and subtherapeutic nasal continuous positive airway pressure for obstructive sleep apnoea: a randomised parallel trial. Lancet. 2002;360:204–210. Kessler R, Weitzenblum E, Chaouat A, et al. Evaluation of unattended automatic titration to determine therapeutic continuous positive airway pressure in patients with obstructive sleep apnea. Chest. 2003;123:704–710. Farre R, Montserrat JM, Rigau J, et al. Response of automatic continuous positive airway pressure devices to different sleep breathing patterns: a bench study. Am J Respir Crit Care Med. 2002;166:469–473. Rodenstein DO. Automatically controlled continuous positive airway pressure: a bright past, a dubious future. Eur Respir J. 2000;15:985–987.
American Journal of Therapeutics (2015) 0(0)
Copyright Ó 2015 Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited.
Comparison of Efficacy and Tolerance of Automatic Continuous Positive Airway Pressure Devices With the Optimum Continuous Positive Airway Pressure George Tommi, MD,1 Wilbert S. Aronow, MD,2* John C. Sheehan, MD,1 Matthew T. McCleay, MD,1 and Patrick G. Meyers, MD1
Patients diagnosed with obstructive sleep apnea syndrome were randomly placed on automatic continuous positive airway pressure (ACPAP) for 2 hours followed by manual titration for the rest of the night. One hundred sixty-one patients entered the study, with at least 50 patients titrated with each of 3 ACPAP devices. The optimum continuous positive airway pressure (CPAP) was defined as the lowest pressure with an apnea–hypoxia index of #5/hr, which ranged from 4 cm to 18 cm. Success with ACPAP was approximately 60%–80% when the optimum CPAP was 4–6 cm but fell to below 30% if the optimum CPAP was $8 cm (P 5 0.001). Average ACPAP ranged from 2 to 10 cm below the optimum level if the optimum CPAP was $8 cm. Patients who responded to a low CPAP but deteriorated on higher pressures failed to respond to any of the automatic devices. We recommend that CPAP titration be performed manually before initiation of ACPAP in patients with obstructive sleep apnea. The basal pressure for ACPAP should be the optimum pressure obtained by manual titration. Limits on the upper level of ACPAP may be necessary for patients who deteriorate on higher positive pressures. Keywords: continuous positive airway pressure, obstructive sleep apnea, apnea–hypoxia index
INTRODUCTION The prevalence of obstructive sleep apnea (OSA) in the general population is estimated to be 24% in men and 9% in women.1 Serious cardiovascular and central nervous system complications with increased morbidity and mortality associated with OSA warrant medical intervention with continuous positive airway pressure (CPAP) being the most successful
1
Midwest Pulmonary and Critical Care, Creighton University, Omaha, NE; and 2Division of Cardiology, Department of Medicine, Westchester Medical Center, New York Medical College, Valhalla, NY. The authors have no conflicts of interest to declare. *Address for correspondence: Division of Cardiology, Department of Medicine, New York Medical College, Macy Pavilion, Room 138, Valhalla, NY 10595. E-mail: [email protected]
noninvasive therapy for this disorder.2–4 Automatic continuous positive airway pressure (ACPAP) devices have been introduced in the treatment regimen because problems with compliance and intolerance to CPAP occur in over 30% of patients treated with CPAP.5 Moreover, the cost of an overnight polysomnogram (PSG) and the need for a possible second night CPAP titration have made the use of these automatic devices more common.6 Authors have suggested that the optimum CPAP tends to be higher in patients with severe OSA, high body mass index, or large neck circumference, although the exact correlation is unclear. The optimum CPAP does not always correlate with the severity of the apnea–hypopnea index (AHI), and patients with severe OSA may respond to a low optimum CPAP.7,8 This study investigated whether efficacy and tolerance to ACPAP would be the same as manual titration if the optimum CPAP was $6 cm.
1075–2765 Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.
www.americantherapeutics.com
Copyright Ó 2015 Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited.
Tommi et al
2
METHODS A prospective double-blind study was performed comparing 3 different ACPAP devices that are commonly used (ResMed, Fisher Paykel, and Respironics) with various optimum CPAPs. Inclusion criteria were patients older than 18 years with an AHI above 5/hr on an overnight PSG who agreed to an overnight PSG for manual CPAP/ACPAP titration and who agreed to participate in the study. Patients were excluded if they were unable to tolerate CPAP, were claustrophobic, did not respond to CPAP titration, failed manual titration (unable to get the AHI below 5/hr on manual titration), refused to participate in the study, or had acute medical problems. A second overnight PSG for CPAP titration was performed within 2 weeks, and each month a different device was used. The technician randomly chose one of the 3 ACPAP devices until at least 50 patients were studied. ACPAP was initiated randomly in the first or second half of the night for at least 2 hours. Using the same CPAP device, manual titration was initiated from 4 cm to 12 cm for 30–45 minutes in each pressure. If apnea or hyponea persisted at 12 cm, titration up to 18 cm was performed. Airflow was measured using thermistors at the nose and mouth, and respiratory and abdominal effort was measured using respiratory and abdominal piezo belts. Obstructive apnea was defined as no airflow for at least 10 seconds associated with respiratory and/or abdominal wall movements. Hypopnea was defined as decreased airflow by at least 30% for at least 10 seconds associated with a 4% desaturation or a 50% decrease in airflow for at least 10 seconds associated with an arousal. The optimum CPAP was defined as the lowest pressure required to reduce the AHI at or below 5/hr. Success rates were compared between groups using an exact Pearson x2 test. Mean age was compared between successes and failures using a Mann–Whitney test. The distribution of gender was approximately balanced across the 3 groups with 38%, 33%, and 33% females in the Fisher Paykel, ResMed, and Respironics groups, respectively. Age was also similar among the groups with mean ages of 54.4 years, 57.4 years, and 58.6 years for the Fisher Paykel, ResMed, and Respironics groups, respectively. Success was defined as an AHI at or below 5/hr. There was a significant difference in the success rates by device. The distribution of success by device was: Fisher Paykel, 56%; ResMed, 27%; and Respironics, 43% (P , 0.001). For all devices combined, the proportion of successes was higher for the ,8 cm pressure group compared with the $8 cm pressure group (56% vs. 16%, P , 0.001, Fisher exact American Journal of Therapeutics (2015) 0(0)
test). The success rate for the ,8 cm pressure group compared with the $8 cm pressure group for Fisher Paykel was 79% versus 24% (P 5 0.001, Fisher exact test), for ResMed was 34% versus 8% (P 5 0.08), and for Respironics 62% versus 15% (P 5 0.001).
RESULTS One hundred sixty-one patients were evaluated and entered the study. Male to female ratio was 7:3, and ages ranged from 25 to 90 years with a mean age of 56.8 years. The initial AHI ranged from 6 to 80 an hour, and the optimum CPAP levels ranged from 4 cm to 18 cm. Fifty-three patients were placed on ResMed, 54 patients on Respironics, and 54 patients on Fisher Pakyel. Six patients titrated on bilevel positive airway pressure, and 14 patients who failed to respond to CPAP were discontinued from the study. When the optimum CPAP was 4 or 6 cm, efficacy for the 3 devices ranged between 60% and 80%, Fisher Pakyel being the most effective. Efficacy to the 3 devices was less than 30% when the optimum CPAP was $8 cm. The average ACPAP correlated less than 33% with Fisher Pakyel and ResMed but was approximately 50% with Respironics when the optimum CPAP was $8 cm (Tables 1 and 2). Six patients who responded well to a lower CPAP but deteriorated on a higher CPAP failed to respond to any of the ACPAP devices. One patient on ResMed, 3 patients on Fischer Paykel, and 7 patients on Respironics did not tolerate ACPAP titration and were included in the failures. There was a significant difference in the success rates by device. The distribution of success by device was Fisher Paykel, 56%; ResMed, 27%; and Respironics, 43% (P , 0.001). For all devices combined, the proportion of successes was higher for the ,8 cm pressure group compared with the $8 cm pressure group (56% vs. 16%, P , 0.001, Fisher exact test). The success rate for the ,8 cm pressure group compared with the $8 cm pressure group for Fisher Paykel was 79% versus 24% (P 5 0.001, Fisher exact test), for ResMed 34% versus 8% (P 5 0.08), and for Respironics 62% versus 15% (P 5 0.001).
DISCUSSION The severity of AHI is known to vary nightly and tends to be more severe in the supine position, with rapid eye movement sleep and with use of sedatives, hypnotics, and alcohol.9,10 ACPAP devices have been used in the management of OSA over the last few years, and these devices are supposed to increase or decrease the pressure depending on the severity of the www.americantherapeutics.com
Copyright Ó 2015 Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited.
Optimum CPAP
3
Table 1. Average ACPAP compared with various optimal CPAP with 3 ACPAP devices. opCPAP (4/6 cm) ACPAP device average pressure ResMed 36 patients 16 patients Respironics 32 patients 22 patients Fisher Paykel 31 patients 22 patients
opCPAP ($8 cm)
Discard
.2 cm
.4 cm
.6 cm
,2 cm
,4 cm
8 —
1 —
2 —
— 8
— 4 (1 , 10 cm)
1
— 4
5 —
2 —
6 —
— 4
— 1
1 5
1 2
9 —
2 —
7 —
— 9
— 8 (2 , 9 cm)
3
3 5
Sleep Efficiency ,25%
opCPAP, optimal CPAP.
AHI and snoring. The downside to our method of manual CPAP titration is that rapid eye movement sleep and the supine position do not occur at each pressure. However, the response to each pressure is easily documented with our titration, and the optimum pressure determined by other methods could vary significantly depending on the PSG technician performing the study. This method would also identify patients who deteriorate on higher pressures of CPAP. All patients were followed for at least 6 months and, in this study, no pressure changes were made. Several ACPAP devices are currently in use, and their mechanism of action defers from each other.11–15 The ResMed Autoset device detects respiratory events using a multiple breath moving average technique and responds to any airway changes, such as flow limitation, apneas, and snoring. This device postulates that flow limitation precedes snoring and apneas and that the pressure is increased in these situations. These devices also are supposed to calculate the pressure needed based on the severity of the event. The Respironics autoset device analyzes changes in flatness, roundness, peak, and
shape of the flow. It also has the capability to detect vibrations from snoring and adjusts the pressure. This device has a nonresponsive apnea/hyponea logic that is supposed to reduce the pressure to manage respiratory events that are nonresponsive to high CPAP. The Fisher Paykel automatic set device monitors flow in a 5-breath moving window and responds to flow limitation, apneas, and hyponeas. The “Senswake” mode in these devices detects the pattern of irregular breathing that occurs at the transition from sleep to wake and reduces the pressure until the minimum or sensawake pressure is reached, which takes until 2 minutes. These automatic devices have been reported to be as effective as manual titration, and some investigators have suggested that patients be initiated on ACPAP without manual titration. However, most of these studies enrolled small number of patients, and all of them compared the efficacy with the severity of AHI but not to the optimum CPAP.10,12 In studies where the ACPAP was allowed to titrate from 4 cm to 16 cm, the average CPAP was 2–6 cm below the optimum CPAP pressure and most of these patients
Table 2. Comparing success by pressure groups with ACPAP devices and various optimum CPAPs. Device ResMed Fisher Paykel Respironics All devices combined
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Pressure (cm) ,8 $8 ,8 $8 ,8 $8 ,8 $8
Success, n (%) 12 1 19 4 18 3 49 8
(34) (8) (79) (24) (62) (15) (56) (16)
Failure, n (%) 23 12 5 13 11 17 39 42
(66) (92) (21) (76) (38) (85) (44) (84)
P 0.08 0.001 0.001 ,0.001
American Journal of Therapeutics (2015) 0(0)
Copyright Ó 2015 Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited.
4
demonstrated an increase in excessive daytime sleepiness.16–18 Condos et al showed that a reduction in constant CPAP pressure of 2 mbar was associated with partial collapse of the upper airways.19,20 Subtherapeutic pressures compared with therapeutic CPAP pressures show failure to improve excessive daytime sleepiness, hypertension, daytime PaO2 levels, and cognitive function in OSA patients.21,22 Efficacy varies significantly with different ACPAP devices tested, and automatic titration should not be performed at home.11,15,23 Patients who do not snore or had upperairway surgery fail to respond to automatic devices dependent on vibration only.12 Devices monitoring snoring, flow, or impedance (forced-oscillation technique) fail adequately to titrate to respiratory events if there are mask or mouth leaks. Rapid alterations with awake and sleep or occurrence of central apneas limit the efficacy of these automatic devices resulting in prolonged periods of high pressure causing more air leaks and sleep fragmentation. These ACPAP devices are also not recommended for patients with hypoventilation obesity syndrome, severe chronic obstructive pulmonary disease, asthma, and heart failure.10,12,14,24,25 Patients who deteriorate on higher CPAP should not be placed on ACPAP because there is a risk of these devices delivering very high pressures. In conclusion, we found that ACPAP fails to show efficacy in patients with OSA if the optimum CPAP is $8 cm. We recommend from our data that the baseline pressure for automatic devices be the optimum pressure obtained by manual titration. The maximum pressure for these automatic devices should be limited in patients who deteriorate on higher CPAP levels.
ACKNOWLEDGMENTS The authors thank Jody Woodard, Jody Blakely, and Shannon Wilson for collecting and recording the data. The authors thank the sleep technologists at Midwest Sleep Laboratory for randomization and monitoring the protocol. The authors thank Jane Mezza, Professor and Chair, Department of Biostatistics at the University of Omaha Medical Center, for her invaluable help in analyzing the data.
REFERENCES 1. Young T, Palta M, Dempsey J, et al. The occurrence of sleep-disordered breathing among middle-aged adults. N Engl J Med. 1993;328:1230–1235. American Journal of Therapeutics (2015) 0(0)
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