Conventional Continuous Positive Airway Pressure Research Articles

Variety of Expiratory Resistance Between Different Continuous Positive Airway Pressure Devices for Preterm Infants

Continuous positive airway pressure (CPAP) systems for preterm infants work with conventional ventilators or use a jet ventilation system. It is assumed that the most important advantage of jet-CPAP systems is a lower expiratory resistance (R(E) ). We investigated the R(E) of seven different CPAP systems. We studied two primary-care CPAP systems, three jet-CPAP generators, and two conventional CPAP devices. All devices were adjusted at 6 mbar and connected with a test lung simulating a standardized expiration volume. Maximum pressure increase during expiration was measured and maximum R(E) was calculated. In primary-care CPAP devices, the maximum R(E) of the Benveniste valve was 9.7 mbar/L/s (SD 1.2) while that of the Neopuff was 102.8 mbar/L/s (SD 7.9) (P < 0.01). In jet-CPAP devices, the R(E) of the Infant Flow was 6.8 mbar/L/s (SD 1.7), the one of the Medijet REF 1000 was 43.5 mbar/L/s (SD 1.5), and that of the Medijet REF 1010 was 36.7 mbar/L/s (SD 0.3) (P < 0.01). In conventional CPAP systems, the R(E) of the Baby Flow was 29.7 mbar/L/s (SD 1.1) and that of the Bubble CPAP was 37.1 mbar/L/s (SD 4.3) (P < 0.01). All CPAP devices created an R(E). Jet-CPAP devices did not produce lower R(E) than conventional CPAP devices.

Canadian Thoracic Society 2011 Guideline Update: Diagnosis and Treatment of Sleep Disordered Breathing

The Canadian Thoracic Society (CTS) published an executive summary of guidelines for the diagnosis and treatment of sleep disordered breathing in 2006⁄2007. These guidelines were developed during several meetings by a group of experts with evidence grading based on committee consensus. These guidelines were well received and the majority of the recommendations remain unchanged. The CTS embarked on a more rigorous process for the 2011 guideline update, and addressed eight areas that were believed to be controversial or in which new data emerged. The CTS Sleep Disordered Breathing Committee posed specific questions for each area. The recommendations regarding maximum assessment wait times, portable monitoring, treatment of asymptomatic adult obstructive sleep apnea patients, treatment with conventional continuous positive airway pressure compared with automatic continuous positive airway pressure, and treatment of central sleep apnea syndrome in heart failure patients replace the recommendations in the 2006⁄2007 guidelines. The recommendations on bariatric surgery, complex sleep apnea and optimum positive airway pressure technologies are new topics, which were not covered in the 2006⁄2007 guidelines.

Noise exposure is increased with neonatal helmet CPAP in comparison with conventional nasal CPAP

in adults, noninvasive ventilation via a helmet is associated with significantly greater noise than nasal and facial masks. We hypothesized that noise exposure could be increased with neonatal helmet continuous positive airway pressure (CPAP) in comparison with conventional nasal CPAP (nCPAP). Our primary objective was to compare the noise intensity produced by a neonatal helmet CPAP and a conventional nCPAP system. Furthermore, we aimed to evaluate the effect of the gas flow rate and the presence of the humidifier and the filter on noise levels during neonatal helmet CPAP treatment. in this bench study, noise intensity was measured in the following settings: helmet CPAP, nCPAP, incubator and the neonatal intensive care unit. In helmet CPAP, noise measurements were performed at different gas flow rates (8, 10 and 12 l/min), while in nCPAP, the flow rate was 8 l/min. For both CPAP systems, the level of pressure was maintained constant at 5 cmH(2) O. during neonatal helmet CPAP, the median (interquartile range) noise levels were significantly higher than those during nCPAP: 70.0 dB (69.9-70.4) vs. 62.7 dB (62.5-63.0); P<0.001. In the helmet CPAP, the noise intensities changed with increasing flow rate and with the presence of a humidifier or a filter. noise intensities generated by the neonatal helmet CPAP were significantly higher than those registered while using a conventional nCPAP system. In the helmet, the noise intensity depends on the gas flow rate, and the presence of a humidifier and a filter in the system.

Quality of life, compliance, sleep and nasopharyngeal side effects during CPAP therapy with and without controlled heated humidification

To determine the effect of a controlled heated breathing tube humidifier (cHH) on the quality of life (QOL), compliance and nasopharyngeal side effects during continuous positive airway pressure (CPAP) therapy in patients with obstructive sleep apnea syndrome (OSAS) in comparison with conventional CPAP. In this prospective randomised cross-over study, 44 patients with OSAS were investigated. During the first two consecutive treatment nights monitored by polysomnography, patients were randomly assigned to receive CPAP with or without cHH. Patients were then randomised to receive one of the treatment modalities at home for 4 weeks. Compliance was recorded and questionnaires assessing side effects and QOL were administered. Sleep parameters measured during the nights in the sleep laboratory did not change. The same result applied to QOL and compliance measured after 4 weeks. During the first two nights we found significant differences between CPAP with and without cHH for dryness of mouth (2.0 ± 1.4 vs. 1.4 ± 1.6) in favour of cHH (p < 0.05). Evaluation of coldness of the face showed improvement whereas waking up due to wetness on the face (0.3 ± 0.6 vs. 0.6 ± 0.8; p < 0.05) was slightly increased. Data after 4 weeks confirmed these findings with further subjective improvement in the reduction of side effects. By the using of the technology of cHH QOL and compliance did not improve. The side effects of CPAP therapy without humidification with respect to nasopharyngeal dryness, however, was reduced immediately as well as during the first weeks of treatment.

Improving Heart Rate Variability in Sleep Apnea Patients: Differences in Treatment with Auto-titrating Positive Airway Pressure (APAP) Versus Conventional CPAP

The effect of positive airway pressure treatments in different modalities on the cardiovascular consequences of the disease in sleep apnea patients is still unclear. We aimed to compare auto-titrating positive airway pressure (APAP) and conventional continuous positive airway pressure (CPAP) in terms of improving heart rate variability (HRV) in obstructive sleep apnea patients. This was a prospective study done in a tertiary research hospital. All patients underwent a manual CPAP titration procedure to determine the optimal pressure that abolishes abnormal respiratory events. Then patients underwent two treatment nights, one under APAP mode and one under conventional CPAP mode with a 1-week interval. Forty newly diagnosed obstructive sleep apnea patients were enrolled in the study. We compared heart rate variability analysis parameters between the APAP night and the CPAP night. This final analysis included the data of 28 patients (M/F: 22/6; mean age = 46 +/- 10 years). Sleep characteristics were comparable between the two treatment nights, whereas all-night time domains of HRV analysis such as HF, nuLF, and LF/HF were different between APAP and CPAP nights (2.93 +/- 0.31 vs. 3.01 +/- 0.31; P = 0.041; 0.75 +/- 0.13 vs. 0.71 +/- 0.14; P = 0.027; and 4.37 +/- 3.24 vs. 3.56 +/- 2.07; P = 0.023, respectively). HRV analysis for individual sleep stages showed that Stage 2 LF, nuLF, nuHF, LF/HF parameters entirely improved under CPAP treatment whereas APAP treatment resulted in nonsignificant changes. These results suggest that despite comparable improvement in abnormal respiratory events with APAP or CPAP treatments, CPAP may be superior to APAP in terms of correcting cardiovascular alterations in sleep apnea patients.

Danger of low pressure alarm failure in preterm infants on continuous positive airway pressure

In certain settings of conventional continuous positive airway pressure (CPAP) application, the ventilator may not be able to detect dislodgement of the prongs. This occurs especially in settings with high flow and small prongs. We investigated the relation between ventilator flows, size of the nasal prongs, and pressure generated within the ventilator circuit due to the flow resistance of the prongs. We studied a Baby-flow CPAP connected to a Babylog 8000plus ventilator. Five prongs of increasing size (x-small, small, medium, large, x-large) and one nose mask were connected to the CPAP in turn. Starting at 30 lpm, the flow was reduced in 2 lpm steps. The dynamic pressure caused by the flow resistance of the prongs within the ventilator circuit was recorded. For all devices, we observed a correlation between the reduction of the flow and the reduction in pressure within the ventilator circuit. However, the flow resistance of the x-small prongs generated the highest dynamic pressure (30 mbar at 22 lpm) within the ventilator circuit while the mask gave rise to the lowest pressure (9 mbar at 30 lpm). The pressure value generated with x-small prongs at low flow rate was observed at high flow rate with x-large prongs or with a mask. We conclude that in settings with high flow rates, low CPAP levels, and small prongs, the resistance of the prongs will create enough dynamic pressure within the ventilator circuit to permit the ventilator to compensate a large leakage flow by closing the expiratory valve. Thus, in case of dislodgement of the prongs, the pressure within the ventilator circuit will not decrease below the alarm level, and the machine will not be able to generate an alarm.

Predicting optimal CPAP by neural network reduces titration failure: a randomized study

Continuous positive airway pressure (CPAP) is considered the standard therapy for obstructive sleep apnea syndrome. In the absence of standard protocol, CPAP titration may be unsuccessful. The purpose of this study was to test the hypothesis that application of an artificial neural network (ANN) to CPAP titration would achieve an optimal CPAP pressure within a shorter time interval and would lead to a decrease in CPAP titration failure. One hundred fifteen patients were randomized 1:1 to either conventional CPAP titration (n = 58) or to an ANN-guided CPAP titration (n = 57). Both groups were assessed for time to optimal CPAP pressure, for titration failure, and for CPAP compliance therapy. Patients in the ANN-guided CPAP titration arm were able to achieve optimal CPAP at a shorter time interval compared to the conventional group (198.7 +/- 143.8 min versus 284.0 +/- 126.5 min) (p < 0.001). There was also a lower titration failure in patients randomized to the ANN-guided CPAP titration arm (16%) compared to the conventional arm (36%) (p = 0.02). Compliance with treatment did not differ across the two arms. The use of ANN for guiding CPAP titration may be superior to the conventional method in maximizing the time to achieve optimal CPAP and in reducing CPAP titration failure.

Using a high‐flow respiratory system (Vapotherm®) within a high dependency setting

Vapotherm 2000i is a non-invasive high-flow respiratory support system used mainly in the treatment of type 1 respiratory failure. It uses a mixture of oxygen and air to deliver a set concentration via nasal cannula (or tracheostomy mask). The advantage of this system is the high humidity achieved using the integral heated water system. The system has been used in neonatal practice as a replacement for conventional continuous positive airway pressure (CPAP) but there is little published research within the adult setting about its use. This study discusses the indications for the use of this non-invasive high-flow respiratory support system, the system set up, the benefits and complications of the system. AUDIT DESIGN: An audit of 72 patients was undertaken within the Surgical High Dependency Unit that collected data on the types of patient receiving the therapy, its effectiveness and patient experience. AUDIT FINDINGS: The audit demonstrated reduced respiratory rate and improvement in oxygenation for treated patients. A non-invasive high-flow respiratory support system can be effective at improving oxygenation in hypoxic patients. Patients were generally satisfied with the system and the system seems suitable for use in an adult surgical high dependency setting.

Humidified High-Flow Nasal Cannula

Humidified high-flow nasal cannula (HHFNC) therapy for neonates has become increasingly popular in recent years. It is frequently used in circumstances when continuous positive airway pressure (CPAP) might otherwise have been used. Limited evidence is available to support the specific role, efficacy, and safety of HHFNC in newborns. This evidence suggests that HHFNC provides inconsistent and relatively unpredictable positive airway pressure, but may be effective in the treatment of some neonatal respiratory conditions while being more user-friendly for caregivers than conventional CPAP. Concerns regarding infection risks have resulted in one major HHFNC device being withdrawn from the market before being recently reintroduced. Caution should be exercised in the use of HHFNC in neonates (eg, by limiting its use to relatively lower flows and to relatively larger neonates, while collecting and closely monitoring safety and efficacy data) until further evidence is available to clearly delineate its role, as well as to support its safety and efficacy.

Nasal flow‐synchronized intermittent positive pressure ventilation to facilitate weaning in very low‐birthweight infants: Unmasked randomized controlled trial

Nasal flow-synchronized intermittent positive pressure ventilation (NFSIPPV) is a new non-invasive ventilatory mode that delivers synchronized mechanical breaths through the nasal prongs. An unmasked, prospective randomized controlled trial was conducted to compare the efficacy of NFSIPPV and conventional nasal continuous positive airway pressure (NCPAP) in increasing the likelihood for successful extubation in very low-birthweight infants. Consecutive infants who weighed <1251 g at birth, required endotracheal intubation within 48 h of birth and met specific predetermined criteria for extubation by day 14 of life were recruited. Each infant was randomized to receive either NFSIPPV or NCPAP soon after extubation. Extubation was deemed successful if re-intubation was not needed for at least 72 h. Criteria for re-intubation were persistent severe respiratory acidosis (arterial pH <7.20 with pCO2 >70 mmHg), severe recurrent apneic episodes not responding to increased ventilatory settings and then requiring bag ventilation, and hypoxemia (SaO2 <90% or pO2 <60 mmHg with FiO2 > or =0.70). There were no significant differences in clinical characteristics between the two groups at randomization. Ninety-four percent (30/32) infants were successfully extubated to NFSIPPV but only 61% (19/31) to conventional NCPAP (P > 0.005). Infants assigned to NCPAP failed extubation mainly because of apnea and hypercapnia, and those assigned to NFSIPPV because of hypoxia. Neither procedure induced major adverse effects. NFSIPPV in the post-extubation period is safe and more effective than NCPAP in preventing re-ventilation.

Can the delta Rapid Shallow Breathing Index predict respiratory failure in spontaneously breathing patients receiving positive pressure ventilation?

The Rapid Shallow Breathing Index (RSBI) is derived by dividing the respiratory rate by the tidal volume. Previous work by this group has shown an association between an elevated RSBI (>105) and the need for noninvasive ventilation. Hypothesis: an improvement in RSBI, defined as a decrease from baseline (that is, ΔRSBI) can predict whether patients will develop respiratory failure either when receiving conventional therapy (non-CPAP) or continuous positive airway pressure (CPAP).

An analysis of the evidence‐practice continuum: is surgery for obstructive sleep apnoea contraindicated?

Currently there are multiple surgical interventions utilized in the treatment of adult obstructive sleep apnoea (OSA). The role of these operations remains controversial, with perspectives on treatment efficacy varying considerably. Despite this, their use is proliferating. In this paper, we present the degree of variability that occurs in the application of these procedures, and examine the effectiveness of surgical intervention as a treatment for OSA. A multi-centre retrospective clinical audit of consecutive, unselected surgical cases presenting at the sleep disorder clinics of two teaching hospitals in a major Australian city. Patients acted as their own historical controls, undergoing polysomnography pre and post surgery to gauge effectiveness. On variability demonstrate 94 individuals in this cohort received 220 individual upper airway surgical procedures, 184 occurred in their first operation (mean 2.5 per person; range 1-7) and 36 occurred in a second operation (n=18; cumulative mean of 4 per person; range 3-7). These 94 individuals received 41 varying combinations of surgery. Results on effectiveness demonstrate an overall physiological success rate of 13% (87% fail). One operation reduced OSA severity by 20% (patients still had severe OSA), and two operations by 35% (still moderate OSA). In contrast, conventional Continuous Positive Airway Pressure therapy controlled OSA (n=64). This case study demonstrates substantial procedural variability and limited effectiveness. This raises questions as to the quality of care, the treatment-derived health outcomes of this population and of efficient resource allocation. This issue requires greater policy attention.

Optimising placement of endotracheal tubes in infants referred for neonatal transfer

10 (3–63) 19 (10–47) 0.011 About 2 weeks post randomisation, 94% of infants had successfully weaned in the ‘pressure’ group compared with 67% in the ‘time off’ group. A week later, 97% in the pressure group had weaned compared with 81% in the time off group. A Kaplan–Meier graph on ‘time to wean’ for all patients in both groups was drawn and generated a log rank test with a highly significant p value of <0.001 for differences in median time to wean. Infants weaned via pressure reduction faster [pressure= 36 h (95% CI: 31.3 to 50.7) vs. time off=352 h (95% CI: 209.5 to 494.5)]. Conclusion: For VLBW infants, the gradual reduction in nCPAP pressure may facilitate more rapid respiratory weaning compared with periods of increasing time spent off nCPAP. Reference [1] Sreenan C, Lemke RP, Hudson-Mason A, Osiovich H. High-flow nasal cannula in the management of apnea of prematurity: a comparison with conventional nasal continuous positive airway pressure. Pediatrics 2001;107:

Pressure-Relief Continuous Positive Airway Pressure vs Constant Continuous Positive Airway Pressure: A Comparison of Efficacy and Compliance

To compare polysomnographic data and compliance in sleep apnea patients receiving continuous positive airway pressure (CPAP) and pressure-relief CPAP (PRCPAP) [C-flex; Respironics; Murrysville, PA] as first treatment in the sleep laboratory and subsequently at home. A prospective, randomized, crossover design was used in the sleep laboratory, and a prospective randomized design was used at home. Data were collected from 52 sleep apnea patients for whom CPAP was used for the first time. Treatment with constant CPAP and PRCPAP. Patients with a first-time diagnosis of obstructive sleep apnea syndrome (OSAS) underwent conventional CPAP titration. Thereafter, polysomnography was performed at the titrated pressure using both the fixed CPAP pressure mode and the PRCPAP mode in a randomized crossover approach. The patients were then discharged home for 7 weeks of treatment with the last-applied treatment mode, and compliance data were established at the end of that time. The average apnea-hypopnea index was 53.3/h in the "diagnostic night," 5.8/h with CPAP, and 7.0/h with PRCPAP. The native arousal index was 35.2/h, 12.6/h with CPAP, and 12.9/h with PRCPAP (not significant [NS]). The central apnea index was 0.7/h with CPAP and 1.2/h with PRCPAP (p < 0.05). Compliance after 7 weeks was, on average, 9.4 min longer with PRCPAP than with CPAP (NS). Evaluation of a 13-item questionnaire showed scores of 16.4 for PRCPAP and 18.1 for constant CPAP (NS) [the fewer the complaints, the lower the score]. With regard to oral dryness, the score with PRCPAP (1.4) was significantly lower than with constant CPAP (1.9) [p < 0.05]. This difference was no longer detectable after 7 weeks. In terms of the effectiveness in treating obstructive sleep apnea, PRCPAP and constant CPAP are comparable. During the first night of treatment, patients receiving PRCPAP had less dryness of mouth; over a period of 7 weeks, this difference disappeared. Nightly use of the device was comparable in both groups. PRCPAP is therefore a new ventilation mode that enables effective treatment of OSAS patients. Further studies should be done to investigate the effects of expiratory pressure lowering in low-compliance patients and patients requiring CPAP > 9 cm H(2)O or experiencing dry mouth with CPAP.

Nasal continuous positive airway pressure from high flow cannula versus Infant Flow for preterm infants

To compare the feasibility of continuous positive airway pressure (CPAP) support generated by high flow nasal cannula with conventional CPAP for prevention of reintubation among preterm infants with a birth weight of <or=1,250 g. Preterm infants were randomized to CPAP generated via high flow cannula or the Infant Flow Nasal CPAP System (VIASYS, Conshohocken, PA, USA) at extubation. Primary outcome was incidence of reintubation within 7 days. Secondary outcomes included change in oxygen use and frequency of apnea and bradycardias postextubation. Forty neonates were randomized. Twelve of 20 infants randomized to high flow cannula CPAP were reintubated compared to three of 20 using Infant Flow (P=0.003). The high flow cannula group had increased oxygen use and more apneas and bradycardias postextubation. CPAP delivered by high flow nasal cannula failed to maintain extubation status among preterm infants <or=1,250 g as effectively as Infant Flow CPAP.

Nap-titration: An effective alternative for continuous positive airway pressure titration

When treating Obstructive Sleep Apnea-Hypopnea Syndrome (OSAHS) several alternatives for standard (manual) continuous positive airway pressure (CPAP) titration are feasible. A practical alternative is titration without polysomnography during an afternoon nap (Nap-titration). The aim of the present study was to assess whether Nap-titration is appropriate for effective titration of CPAP. Following Nap-titration 24 eligible OSAHS patients started conventional CPAP therapy. The outcome of Nap-titration was verified after 2 weeks with CPAP pressure adjustments being performed in case of persisting OSAHS symptomatology. Polysomnography and a questionnaire evaluation were performed at baseline and 8 weeks after Nap-titration. Following Nap-titration 15 patients did not require pressure changes while in 9 patients' CPAP pressure was raised due to persisting OSAHS symptomatology. Control polysomnography after 8 weeks showed successful CPAP titration (Apnea-Hypopnea Index <5) in 23 out of 24 patients. A pressure raise following polysomnography was indicated in 1 patient only. In addition, significant improvements were found in OSAHS symptomatology and quality of life. This study shows that in 96% of OSAHS patients' successful CPAP titration is attained following Nap-titration whether or not supplemented by pressure adjustments. Therefore, Nap-titration with an adequate follow-up appears an appropriate procedure for the effective titration of CPAP.

A new device for administration of continuous positive airway pressure in preterm infants: comparison with a standard nasal CPAP continuous positive airway pressure system

We compared the effectiveness of a new continuous positive airway pressure (CPAP) device (neonatal helmet CPAP) with a conventional nasal CPAP system in preterm neonates needing continuous distending pressure. Randomized, physiological, cross-over study in a tertiary referral, neonatal intensive care unit in a university teaching hospital. Twenty very low birth weight infants with a postnatal age greater than 24 h who were receiving nasal CPAP for apnea and/or mild respiratory distress were enrolled. CPAP delivered by neonatal helmet CPAP and nasal CPAP in random order for two subsequent 90-min periods. Were continuously measured the Neonatal Infant Pain Scale (NIPS) score, oxygen requirements, respiratory rate, heart rate, oxygen saturation, transcutaneous PO(2) (tcPO(2)) and PCO(2) (tcPCO(2)), blood pressure, and desaturations. NIPS scores were significantly lower when the infants were on the neonatal helmet CPAP than when they were on nasal CPAP (0.26+/-0.07 vs. 0.63+/-0.12). The other studied parameters did not differ between the two CPAP modes. The number of desaturations was reduced during the neonatal helmet CPAP treatment (18 vs. 32), although this difference was not significant. In this short-term physiological study the neonatal helmet CPAP appears to be as good as the golden standard for managing preterm infants needing continuous distending pressure, with enhanced tolerability. Further evaluation in a randomized clinical trial is needed to confirm these findings.

The Current Status of Autotitrating Continuous Positive Airway Pressure Systems in the Management of Obstructive Sleep Apnea

Autotitrating continuous positive airway pressure (APAP) devices have the potential to address some of the disadvantages of titration and treatment with conventional continuous positive airway pressure (CPAP). Information on the performance of APAP in clinical use is still comparatively limited. To assess the status of APAP devices in the management of obstructive sleep apnea (OSA) by reviewing evidence of their efficacy, effectiveness and costs. A systematic search of electronic databases and a review of selected comparative studies on the use of APAP in the diagnosis, titration and treatment of OSA was undertaken. Cost analysis using data applicable to the management of OSA in Edmonton, Alberta was performed. Thirty-three studies met the selection criteria: three on the use of APAP in diagnosing OSA; six on APAP for titration; 14 that considered short-term treatment outcomes; and 10 that addressed longer-term treatment of OSA. In most studies, patients suffering from cardiac, pulmonary and other medical conditions were excluded. Available data suggested some potential for the use of APAP in the diagnosis of OSA, but further validation is needed. In titration, estimated treatment pressures tended to be lower with APAP than with the manual titration of CPAP. Although lower treatment pressures were achieved with APAP, there was no significant difference in clinical outcome measures between APAP and CPAP. Estimates of costs suggested that APAP may provide savings in some scenarios. APAP shows promise in the management of OSA; however, given the exclusion of some categories of patients from trials of this technology, caution is still required in its use.

Comparative Study of Autotitrating and Fixed-Pressure CPAP in the Home: a Randomized, Single-Blind Crossover Trial

To compare compliance and treatment response between continuous positive airway pressure (CPAP) and auto-titrating positive airway pressure (APAP) and to develop selection criteria for the use of APAP. Randomized, single-blinded, parallel crossover study. Tertiary referral sleep disorders center. Consecutive patients with obstructive sleep apnea syndrome requiring treatment with CPAP. 2-month treatment each of conventional CPAP and APAP in random order comparing objective compliance, Epworth Sleepiness Score, SF-36 Health Survey, visual-analog measures of ease of and attitude to treatment, side effects, and treatment pressures or system leaks obtained from the Autoset T device. There were no differences between treatment modes in overall compliance (CPAP 4.86 +/- 2.65, APAP 5.05 +/- 2.38 hours per night, P = .14), Epworth Sleepiness Scale scores (baseline 12.4 +/- 5.1, CPAP 8.4 +/- 5.2, APAP 7.9 +/- 4.8, P < .001 relative to baseline, NS between modes), SF-36 scores (significant improvements in Role Physical and Vitality domains relative to baseline, P < .001 but NS between modes). There were fewer reported side effects in APAP mode (CPAP 28, APAP 15 reports, P = .02) and compliance was greater with APAP in those reporting any side effect (95% confidence interval CPAP 0-6.8, APAP 2.9-7.8 hours per night, P < .001). APAP delivered significantly lower median and 95th centile airway pressures and fewer system leaks. Compliance, subjective sleepiness, and quality of life are similar between patients who used CPAP and APAP. APAP delivers lower pressures and results in lower-pressure leaks and fewer reported side effects. Compliance is higher with APAP in subjects reporting any side effect. APAP may be indicated in patients reporting side effects with conventional CPAP.

Auto-titrating versus standard continuous positive airway pressure for the treatment of obstructive sleep apnea: results of a meta-analysis.

To compare the effectiveness of auto-titrating continuous positive airway pressure (APAP) versus conventional continuous positive airway pressure (CPAP) in reducing the apnea-hypopnea index (AHI), reducing the mean airway pressure, improving subjective sleepiness, and improving treatment adherence in patients with obstructive sleep apnea (OSA). Meta-analysis and metaregression of published randomized trials comparing APAP to CPAP. N/A. N/A. N/A. We identified 9 randomized trials studying a total of 282 patients. Compared to CPAP, there was no significant advantage of APAP in reducing AHI or sleepiness (pooled APAP-CPAP posttreatment AHI and Epworth Sleepiness Scale score = -0.20 events per hour, 95% confidence interval:[-0.74,0.35], and -0.56 [-1.4,0.3] respectively). The use of APAP reduced the mean applied pressure across the night by 2.2 cm water [1.9,2.5] compared to CPAP. Adherence with therapy was not substantially improved with APAP; pooled estimate of improvement was 0.20 hours per night ([-0.16,0.57], P = .28) using a random-effects model. Compared to standard CPAP, APAP is associated with a reduction in mean pressure. However, APAP and standard CPAP were similar in adherence and their ability to eliminate respiratory events and to improve subjective sleepiness. Given that APAP is more costly than standard CPAP, APAP should not be considered first-line chronic therapy in all patients with OSA. However, APAP may be useful in other situations (eg, home titrations, detection of mouth leak) or in certain subgroups of patients with OSA. Identifying circumstances in which APAP is a definite improvement over CPAP in terms of costs or effects should be the focus of future studies.