The acute impact of continuous positive airway pressure on nasal resistance: a randomized controlled comparison

Impact of posture and CPAP on nasal airflow

Obstructive sleep apnea (OSA) patients who use continuous positive airway pressure (CPAP) often complain of nasal dryness and nasal obstruction as side effects of CPAP. The physiological mechanisms by which CPAP may cause nasal dryness and nasal obstruction remain poorly understood. It has been hypothesized that CPAP interferes with the nasal cycle, abolishing the resting phase of the cycle and leading to nasal dryness. We performed rhinomanometry measurements in 31 OSA patients sitting, laid supine, and supine after 10 min of CPAP at 10 cmH2O. A posture change from sitting to supine led to more symmetric airflow partitioning between the left and right nostrils in the supine position. CPAP did not have a significant impact on nasal resistance, unilateral airflows, or airflow partitioning. Our results suggest that airflow partitioning becomes more symmetric immediately after changing to a supine position, while CPAP had no effect on nasal airflow, thus preserving the nearly symmetric airflow partitioning achieved after the posture change.

Long-term non-invasive ventilation in children: Transition from hospital to home

Long-term non-invasive ventilation (NIV) is an accepted therapy for sleep-related respiratory disorders and respiratory insufficiency or failure. Increase in the use of long-term NIV may, in part, be driven by an increase in the number of children surviving critical illness with comorbidities. As a result, some children start on long-term NIV as part of transitioning from hospital to home. NIV may be used in acute illness to avoid intubation, facilitate extubation or support tracheostomy decannulation, and to avoid the need for a tracheostomy for long-term invasive ventilation. The decision about whether long-term NIV is appropriate for an individual child and their family needs to be made with care. Preparing for transition from the hospital to home involves understanding how NIV equipment is obtained and set-up, education and training for parents/caregivers, and arranging a plan for clinical follow-up. While planning for these transitions is challenging, the goals of a shorter time in hospital and a child living well at home with their family are important.

Nasal Symptoms in Patients with Obstructive Sleep Apnoea and Their Association with Continuous Positive Airway Pressure Usage

The role of nasal symptoms in continuous positive airway pressure (CPAP) tolerance is not completely clear. This study aimed to investigate the association between CPAP usage and nasal symptoms, either prior to, or developing during, CPAP use in patients with obstructive sleep apnoea (OSA). Two hundred thirty patients were studied and divided into high-, low-, and non-CPAP users. Nasal symptoms and related quality of life parameters were evaluated prior to CPAP initiation and after three months. We also investigated predictive factors for CPAP usage. Non-CPAP users had significantly worse baseline scores for runny nose compared with high and low users (1.34 vs. 0.68 and 0.75, respectively, p = 0.006). There were no other significant differences between the groups. Runny nose was an independent predictive factor for lower CPAP usage (p = 0.036). An evaluation after three months showed worsening in runny nose score in high-CPAP users (p = 0.025) but not in low- and non-users. There were no significant changes in other nasal symptoms. Our study demonstrates that nasal symptoms were very common in this population but rhinorrhoea was the only symptom associated with poorer CPAP adherence. Moreover, rhinorrhoea worsened after a three-month trial of high-CPAP usage.

Mask interfaces for home non-invasive ventilation in infants and children

The selection of the mask interface for non-invasive ventilation (NIV) is recognized to be an essential part for therapy success. While nasal masks are the first recommended option in children and adults, there are indications for other mask types such as intolerance or complications from nasal masks. Evidence comparing performance, adherence and complication risk among mask interfaces in pediatrics is, however, scarce and information is often extrapolated from adult studies. Given this gap in knowledge and the lack of guidelines on NIV initiation in children, mask selection often relies on the clinicians' knowledge and expertise. Careful mask selection, a well-fitting headgear and time investment for mask desensitization are some important recommendations for adequate mask adaptation in children. Frequent mask-related complications include nasal symptoms, unintentional leak, mask displacement, skin injury, and midface hypoplasia. Close monitoring and a pro-active approach may help to minimize complications and promote the optimal use of home NIV.

The effect of continuous positive airway pressure therapy on nasal patency

BACKGROUND

Nasal congestion and obstruction are reported in the majority of continuous positive airway pressure (CPAP) users and are frequently cited as reasons for noncompliance. To our knowledge, no study has demonstrated a change in objective or subjective nasal patency in patients with obstructive sleep apnea (OSA) after a therapeutic trial of CPAP therapy.

METHODS

This prospective nonrandomized trial tested the hypothesis that CPAP therapy would result in both objective and subjective improvements in nasal patency in patients with OSA. Prior to initiation of CPAP, acoustic rhinometry (AR) was used to determine nasal volume and minimum cross-sectional area in the upright and reclined positions. Subjective nasal patency was assessed with the Nasal Obstruction Symptom Evaluation (NOSE) questionnaire. Both assessments were repeated at follow-up visits.

RESULTS

AR data demonstrated a statistically significant increase in total nasal volume (TV) in the reclined position (p = 0.002) and minimum cross-sectional area (MCA) in both the sitting and reclined positions (p = 0.006, p = 0.021) in OSA patients after >30 days of CPAP therapy and with >70% compliance. NOSE scores decreased significantly (p = 0.038) representing an improvement in nasal patency.

CONCLUSION

Objective and subjective measurements of TV and MCA increased after initiation of CPAP therapy in this prospective study.

Acute impact of continuous positive airway pressure on nasal patency

BACKGROUND

Continuous airflow in the upper airway can cause discomfort, leading to nasopharyngeal complaints. The aim of the present study is to evaluate the acute effects of continuous positive upper-airway pressure on nasal patency in awake normal subjects.

METHODS

Twenty-seven adults (17 men; 10 women; age range, 18 to 43 years) were exposed to continuous airway pressure (20 cmH₂ O) in the nasal cavity, delivered by a continuous positive airway pressure (CPAP) device through a nasal mask for 2 hours. Visual analogue scale (VAS) of nasal obstruction, Nasal Obstruction Symptom Evaluation (NOSE) modified scale, acoustic rhinometry (AR), and peak nasal inspiratory flow (PF) were measured before and after the use of CPAP.

RESULTS

There was an increase in nasal obstruction scores both on the VAS (p < 0.05) and on the NOSE scale (p < 0.05), as well as a reduction in nasal cavity volume on AR (p < 0.05) and a decline in PF (p < 0.05). Subjects were stratified into 2 groups: with and without symptoms of allergic rhinitis. Nasal parameters were significantly worse in the rhinitis group, with higher nasal obstruction scores on the VAS (p = 0.001) and NOSE scale (p < 0.001) and decreased PF (p < 0.001).

CONCLUSION

Acute exposure to positive pressure via CPAP is associated with subjective and objective reductions in nasal patency. In individuals with allergic nasal symptoms, deterioration is even more severe than in patients without these symptoms.

Noninvasive ventilation in acute respiratory failure

After the institution of positive-pressure ventilation, the use of noninvasive ventilation (NIV) through an interface substantially increased. The first technique was continuous positive airway pressure; but, after the introduction of pressure support ventilation at the end of the 20th century, this became the main modality. Both techniques, and some others that have been recently introduced and which integrate some technological innovations, have extensively demonstrated a faster improvement of acute respiratory failure in different patient populations, avoiding endotracheal intubation and facilitating the release of conventional invasive mechanical ventilation. In acute settings, NIV is currently the first-line treatment for moderate-to-severe chronic obstructive pulmonary disease exacerbation as well as for acute cardiogenic pulmonary edema and should be considered in immunocompromised patients with acute respiratory insufficiency, in difficult weaning, and in the prevention of postextubation failure. Alternatively, it can also be used in the postoperative period and in cases of pneumonia and asthma or as a palliative treatment. NIV is currently used in a wide range of acute settings, such as critical care and emergency departments, hospital wards, palliative or pediatric units, and in pre-hospital care. It is also used as a home care therapy in patients with chronic pulmonary or sleep disorders. The appropriate selection of patients and the adaptation to the technique are the keys to success. This review essentially analyzes the evidence of benefits of NIV in different populations with acute respiratory failure and describes the main modalities, new devices, and some practical aspects of the use of this technique.

Effect of changing airway pressure on the ability of the human nose to warm and humidify air

OBJECTIVES

Nasal continuous positive airway pressure (CPAP) treatment causes nasal symptoms that are believed to result from the drying effects of the air on the nasal mucosa, and these symptoms affect compliance with therapy. We hypothesized that the increased air pressure on the nasal mucosa caused by positive pressure from CPAP would decrease the ability of the nose to warm and humidify inspired air, explaining these symptoms.

METHODS

We performed a 4-way crossover trial using CPAP pressures of -5, 0, +5, and +10 cm H2O in 10 subjects. The ability to warm and humidify inspired air was determined by measurement of the temperature of a fixed volume of cold, dry air entering and exiting the nostril and calculation of the amount of water supplied to the airstream by the nose.

RESULTS

The water content of air was unaffected at the pressures studied.

CONCLUSIONS

The pressure of delivered CPAP does not affect the ability of the nose to warm and humidify inspired air.