Filters Reduce the Risk of Bacterial Transmission from Contaminated Heated Humidifiers Used with CPAP for Obstructive Sleep Apnea

Obstructive Sleep Apnea and Acute Lower Respiratory Tract Infections: A Narrative Literature Review

Both obstructive sleep apnea (OSA) and acute lower respiratory tract infections (LRTIs) are important global health issues. The pathophysiological links between OSA and LRTIs include altered immune responses due to chronic intermittent hypoxia and sleep fragmentation, increased aspiration risk, and a high burden of comorbidities. In this narrative review, we evaluated the current evidence on the association between OSA and the incidence and outcomes of acute LRTIs in adults, specifically community-acquired pneumonia and viral pneumonia caused by influenza and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Studies have demonstrated that OSA patients are more likely to develop bacterial pneumonia and exhibit a higher risk of invasive pneumococcal disease. The risk intensifies with the severity of OSA, influencing hospitalization rates and the need for intensive care. OSA is also associated with an increased risk of contracting influenza and suffering more severe disease, potentially necessitating hospitalization. Similarly, OSA contributes to increased COVID-19 disease severity, reflected by higher rates of hospitalization, longer hospital stays, and a higher incidence of acute respiratory failure. The effect of OSA on mortality rates from these infections is, however, somewhat ambiguous. Finally, we explored antibiotic therapy for OSA patients with LRTIs, addressing care settings, empirical regimens, risks, and pharmacokinetic considerations. Given the substantial burden of OSA and its significant interplay with acute LRTIs, enhanced screening, targeted vaccinations, and optimized management strategies for OSA patients should be prioritized.

Can humidifier reservoir bacteria colonize the circuit during mechanical ventilation: An in vitro study

BACKGROUND

Although the circuit condensate, an ideal bacterial reservoir during mechanical ventilation, may flow into the humidifier reservoir, no studies have investigated if humidifier reservoir colonized bacteria colonize other circuit locations with airflow.

AIMS

We aimed to prove whether the humidifier reservoir colonized bacteria colonize other circuit locations with airflow and provide some advice on the disposal of condensate in the clinical setting.

STUDY DESIGN

An in vitro experiment was conducted. Mechanical ventilation simulators (n = 90) were divided into sterile water group (n = 30) and broth group (n = 60). In the sterile water group, sterile water was used for humidification, either Acinetobacter baumannii or Pseudomonas aeruginosa were inoculated to humidifier water in the humidifier reservoir, each accounted for 50% of the simulators. The broth group was performed the same as the sterile water group except for the addition of broth into the humidified water. After 24, 72, and 168 h of continuous ventilation, the humidifier water and different locations of the circuits were sampled for bacterial culture.

RESULTS

All bacterial culture results of the sterile water group were negative. Bacteria in the humidifier water continued to proliferate in the broth group. With prolonged ventilation, the bacteria at the humidifier reservoir outlet increased. The bacteria at the humidifier reservoir outlet were much more in the Pseudomonas aeruginosa subgroup than in the Acinetobacter baumannii subgroup and the difference was statistically significant (p < .05). During continuous ventilation, no bacterial growth occurred at 10 cm from the humidifier reservoir outlet and the Y-piece of the ventilator circuits.

CONCLUSIONS

Sterile water in the humidifier reservoir was not conducive to bacterial growth. Even if bacteria grew in the humidifier reservoir and could reach the humidifier reservoir outlet, colonization of further circuit locations with the airflow was unlikely. During a certain mechanical ventilation time, the amount of bacteria reaching the outlet of the humidifier reservoir varied due to different mobility of bacteria.

RELEVANCE TO CLINICAL PRACTICE

In a clinical setting, nurses should not worry about a small amount of condensate backflow into the humidifier reservoir. Draining condensate into the humidifier reservoir can be used as a low risk and convenient method in clinical practice.

Effects of using in-line bacterial filters with continuous positive airway pressure devices in patients with sleep disordered breathing

In June 2021, Philips Respironics first advised the use of in-line bacterial filters in response to a recall of continuous positive airway pressure (CPAP) devices. However, the effects of using in-line filters with CPAP devices have not yet been examined in a clinical setting. Here, we retrospectively evaluated 160 patients with sleep-disordered breathing (SDB) who voluntarily used in-line bacterial filters. Patients' perceptions of CPAP pressure after using in-line filters were investigated via a verbal interview. Patients described CPAP pressure as very weak (13, 8.1%), somewhat weak (42, 26.2%), unchanged (103, 64.4%), or somewhat strong (2, 1.3%). Five of the thirteen patients (38.5%) who described CPAP pressure as very weak discontinued the use of in-line filters. The apnea-hypopnea index obtained from the CPAP devices did not change after using in-line filters (n = 129, p = 0.85). Hence, although in-line bacterial filters could change patients' perceptions of CPAP pressure, they did not influence SDB control.