Dataset Information

Increased propensity for central apnea in patients with obstructive sleep apnea: effect of nasal continuous positive airway pressure.

ABSTRACT:

Rationale

There is increasing evidence of increased ventilatory instability in patients with obstructive sleep apnea (OSA), but previous investigations have not studied whether the hypocapnic apneic threshold is altered in this group.

Objectives

To compare the apneic threshold, CO2 reserve, and controller gain between subjects with and without OSA matched for age, sex, and body mass index.

Methods

Hypocapnia was induced via nasal mechanical ventilation for 3 minutes. Cessation of mechanical ventilation resulted in hypocapnic central hypopnea or apnea depending upon the magnitude of the hypocapnia. The apnea threshold (Pet(CO2)-AT) was defined as the measured Pet(CO2) at which the apnea closest to the last hypopnea occurred. The CO2 reserve was defined as the change in Pet(CO2) between eupneic Pet(CO2) and Pet(CO2)-AT. Controller gain was defined as the ratio of change in Ve between control and hypopnea or apnea to the DeltaPet(CO2).

Measurements and main results

Eleven pairs of subjects were studied. There was no difference in the Pet(CO2)-AT between the two groups. However, the CO2 reserve was smaller in the subjects with OSA (2.2 +/- 0.6 mm Hg) compared with the control subjects (4.5 +/- 1.4 mm Hg; P < 0.001). The controller gain was increased in the subjects with OSA (3.7 +/- 1.3 L/min/mm Hg) compared with the control subjects (1.6 +/- 0.5 L/min/mm Hg; P < 0.001). Controller gain decreased and CO2 reserve increased in seven subjects restudied after using continuous positive airway pressure for 1 month.

Conclusions

Ventilatory instability is increased in subjects with OSA and is reversible with the use of continuous positive airway pressure.

SUBMITTER: Salloum A

PROVIDER: S-EPMC2809244 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:Background Studies have shown that a significant percentage of patients with obstructive sleep apnea (OSA) do not tolerate continuous positive airway pressure (CPAP) therapy and long-term use may be as low as 30%. Given the lower levels of symptoms and health-related risks, patients with mild sleep apnea may be at even higher risk for non-adherence to long term CPAP. The purpose of our study was to investigate the prevalence and associations of long-term CPAP adherence in first time users with mild sleep apnea diagnosed by home sleep apnea testing (HSAT). Methods We identified all the patients who were diagnosed with mild sleep apnea (5 = < AHI < 15) by home sleep apnea testing from 01/2013 to 06/2019 at a large, combined community and hospital-based sleep practice. Only first time CPAP users were included. Compliance was defined as CPAP usage ≥ 4 h per night on ≥ 70% of nights over 30 consecutive days. We defined long term adherence as compliance on the 12th month following CPAP set up. Patient demographics, comorbidities, and CPAP compliance at 1st, 3rd, 6th, 9th and 12th month after therapy initiation were collected. We compared and identified the factors that had significant difference (P < 0.1) between compliant and non-compliant groups at the 12th month. Results 222 patients were included in the analysis. 57 (25.7%) patients were adherent with long term CPAP treatment. The following factors were associated with a greater likelihood for long-term CPAP adherence: older age, lower body mass index (BMI), presence of a bed partner, non-smoker, presence of Diabetes Mellitus (DM), presence of Heart Failure (CHF), lack of depression, and compliance at 1st, 3rd, 6th and 9th month. Conclusions Long term CPAP compliance in mild sleep apnea patients is low. Long term adherence to CPAP can be predicted based on CPAP adherence during the first three months. Supplementary Information The online version contains supplementary material available at 10.1186/s12890-023-02612-3.

Project description:Nasal breathing disorders are associated with obstructive sleep apnea (OSA) syndrome and influence the availability of continuous positive airway pressure (CPAP) therapy. However, information is scarce about the impact of nasal resistance assessed by rhinomanometry on CPAP therapy. This study aimed to examine the relationship between CPAP adherence and nasal resistance evaluated by rhinomanometry, and to identify clinical findings that can affect adherence to CPAP therapy for patients with OSA. This study included 260 patients (199 men, 61 women; age 58 [interquartile ranges (IQR) 50-66] years) with a new diagnosis of OSA who underwent rhinomanometry (before, and 1 and 3 months after CPAP introduction) between January 2011 and December 2018. CPAP use was recorded, and the good and poor CPAP adherence groups at the time of patient registration were compared. Furthermore, those with improved and unimproved pre-CPAP high rhinomanometry values were also compared. Their apnea-hypopnea index (AHI) by polysomnography at diagnosis was 45.6 (IQR 33.7-61.6)/hour, but the residual respiratory event (estimated AHI) at enrollment was 2.5 (IQR 1.4-3.9)/hour and the usage time was 318 (IQR 226-397) minutes, indicating that CPAP was effective and adherence was good. CPAP adherence was negatively correlated with nasal resistance (r = -0.188, p = 0.002). The participants were divided into good (n = 153) and poor (n = 107) CPAP adherence groups. In the poor adherence group, rhinomanometry values before CPAP introduction were worse (inspiration, p = 0.003; expiration, p = 0.006). There was no significant difference in patient background when comparing those with improved (n = 16) and unimproved (n = 12) pre-CPAP high rhinomanometry values. However, CPAP usage time was significantly longer in the improved group 1 month (p = 0.002) and 3 months (p = 0.026) after CPAP introduction. The results suggest that nasal resistance evaluated by rhinomanometry is a useful predictor of CPAP adherence, and that improved rhinomanometry values may contribute to extending the duration of CPAP use.