SESSION TITLE: Infectious Disease Global Case Reports
SESSION TYPE: Global Case Report
PRESENTED ON: Tuesday, October 28, 2014 at 01:30 PM - 02:30 PM
INTRODUCTION: Obstructive sleep apnoea (OSA) is relatively common. Nasal continuous positive airway pressure (nCPAP) is treatment of choice, but compliance is hindered by upper airway dryness. Heated humidifiers may improve compliance; however, their use may increase the risk of respiratory infection. Pseudomonas aeruginosa (P. aeruginosa) is usually a nosocomial pathogen associated with hospitalization, resistance to antibiotics, poor outcomes and high mortality. We present a rare case of severe, life threatening, community acquired pneumonia (CAP) due to P aeruginosa infection associated with use of nCPAP with humidifier for OSA.
CASE PRESENTATION: A 73 years female, resident of USA, visiting India since 1 month, with no past history of lung disease, immunocompromised state, recent hospital admission, or prior antibiotic use, presented with cough and fever since 2 weeks. Chest X-ray showed bilateral lower lobe infiltrates. Diagnosed as severe CAP, she worsened rapidly, was transferred to ICU and had to be ventilated within the first day. Sputum cultured at admission grew P. aeruginosa. With appropriate antibiotics, ventilator and supportive care she recovered over the next 2 months. Endo-tracheal (ET) secretions also grew P.aeruginosa sensitive only to Colistin. On further enquiry, we found that she had been diagnosed with OSA 4 years ago and had been using nCPAP with humidifier since then. She continued to use the same humidifier in India sourcing local distilled water. Culture of the humidifier fluid and distilled water, grew P aeruginosa with the same high resistance pattern as that seen in the ET secretions, sensitive only to Colistin.
DISCUSSION: P. aeruginosa as cause of CAP is rare. It is usually seen in patients with cystic fibrosis, severe immunodeficiency, structural lung disease or with poor hygiene of the humidifier. CPAP is being increasingly used as the preferred treatment for OSA, often with humidifiers. Most patients receive few instructions about the risks and precautions associated with its use, especially about cleaning. It is believed that humidification adds moisture to inhaled air by vaporization without production of aerosols, hence, theoretically, humidifiers should not transmit infection. (1) Yet in 206 patients treated with CPAP for OSA, there were more infections among CPAP patients (43%) than controls with OSA who did not use CPAP (25%). Among CPAP users, incidence of upper airway infections was higher in those using humidifiers (22% vs 2%). Patients using heated humidifiers without regard to good hygienic practices in maintaining their humidifiers showed a dramatic increase in upper airway infections, compared with those who cared for their equipment regularly (52.4% vs 13.3%; p < 0.05). (2). Use of hydrophipic filters has been shown to reduce transmission of microbes in heated humidifier circuits. (Ref 3)
CONCLUSIONS: While most infections due to humidifiers occur in the upper airways, our case is unique in that it highlights the possibility of potentially life-threatening complication (Severe CAP) due to respiratory devices. It also draws attention to high level of drug resistant P pseudomonas in the community and to the need for humdifier hygiene.
Reference #1: Wnzel M, Klauke M,et al. Sterile water is unnecessary in a continuous positive airway pressure convection humidifier in the treatment of obstructive sleep apnea syndrome. Chest. 2005 Oct;128(4):2138-40
Reference #2: Sanner BM, Fluerenbrock N, Kleiber-Imbeck A, Mueller JB, Zidek W. Effect of continuous positive airway pressure therapy on infectious complications in patients with obstructive sleep apnea syndrome. Respiration. 2001;68:483-7
Reference #3: Girolamo A. Ortolano, Ph.D., et al. Filters Reduce the Risk of Bacterial Transmission from Contaminated Heated Humidifiers Used with CPAP for Obstructive Sleep Apnea. J Clin Sleep Med. 2007 December 15; 3(7): 700-705
DISCLOSURE: The following authors have nothing to disclose: Sanjeev Mehta, Miti Maniar, Anurati Mehta
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