New Insights into the Prevention of Hospital-Acquired Pneumonia/Ventilator-Associated Pneumonia Caused by Viruses

Abstract

A fifth or more of hospital-acquired pneumonias may be attributable to respiratory viruses. The SARS-CoV-2 pandemic has clearly demonstrated the potential morbidity and mortality of respiratory viruses and the constant threat of nosocomial transmission and hospital-based clusters. Data from before the pandemic suggest the same can be true of influenza, respiratory syncytial virus, and other respiratory viruses. The pandemic has also helped clarify the primary mechanisms and risk factors for viral transmission. Respiratory viruses are primarily transmitted by respiratory aerosols that are routinely emitted when people exhale, talk, and cough. Labored breathing and coughing increase aerosol generation to a much greater extent than intubation, extubation, positive pressure ventilation, and other so-called aerosol-generating procedures. Transmission risk is proportional to the amount of viral exposure. Most transmissions take place over short distances because respiratory emissions are densest immediately adjacent to the source but then rapidly dilute and diffuse with distance leading to less viral exposure. The primary risk factors for transmission then are high viral loads, proximity, sustained exposure, and poor ventilation as these all increase net viral exposure. Poor ventilation increases the risk of long-distance transmission by allowing aerosol-borne viruses to accumulate over time leading to higher levels of exposure throughout an enclosed space. Surgical and procedural masks reduce viral exposure but do not eradicate it and thus lower but do not eliminate transmission risk. Most hospital-based clusters have been attributed to delayed diagnoses, transmission between roommates, and staff-to-patient infections. Strategies to prevent nosocomial respiratory viral infections include testing all patients upon admission, preventing healthcare providers from working while sick, assuring adequate ventilation, universal masking, and vaccinating both patients and healthcare workers.

Comparison Study between Using Disposable and Non-Disposable Ventilator Circuits on Ventilator-Associated Pneumonia and Health Care Costs at a Respiratory Care Unit, Siriraj Hospital

“…(1) guidelines for preventing and controlling hospital infections, such as providing instructions for staff on infection prevention, proper hand washing, and on the appropriate number of personnel; (2) guidelines for reducing bacterial growth, such as washing hands before contact with patients and keeping the environment clean, proper antibiotic use, the provision of proton-pump inhibitors based on necessity, oral cavity cleaning, In addition to reducing complications from mechanical ventilation, weaning from ventilators as soon as possible also reduces expenses in other areas 19 ; and (3) guidelines for reducing aspiration, such as by positioning patients' heads to be at a 30-45 degree angle, controlling the intra-cuff pressure of ETT at 25-30 cmH 2 O, suctioning saliva before suctioning in ETT, assessing the amount of gastric content, preventing condensate fluids from entering patients, and not changing the ventilator circuits more than every seven days. 9,12 Many institutions have developed guidelines from evidence-based practices and found the aforementioned practices to be able to reduce the incidence of VAP. The researcher's own agency implemented "guidelines for preventing ventilatorassociated pneumonia in adults" from Siriraj Hospital or the WHAP-C Bundle in every patient who was on a ventilator.…”

“…9,10 Many factors contribute to VAP, including patient factors and factors related to the examination and treatment procedures, such as the patient's age, disease severity, immunodeficiency, the use of proton-pump inhibitors, the use of narcotics or neuromuscular blocking agents, previous antibiotic exposure, emergency intubation, re-intubation, bronchoscopy, and contaminated medical equipment, such as nebulizers and ventilator circuits. 9,11,12 In the RCU, used ventilator circuits are sterilized before use by the next patient. However, if the cleaning and disinfection processes are performed inadequately, infections can break out among patients.…”

Mechanical ventilation

“…Research is underway to determine which combination of interventions is most effective in reducing these rates. 23 Repositioning oral endotracheal tubes from one side of the mouth to the other is also recommended for oral hygiene to allow for assessment of skin integrity and to reduce the risk of pressure-related injury. 24 Hospital policies should provide procedural guidelines on the frequency of repositioning, who is responsible, who should be present to perform it (generally two people, often a nurse and a respiratory therapist), and the issues related to assessing for skin integrity and pressure injuries.…”

“…Prevention bundles are often utilized to reduce rates of HAP and VAP in patients receiving mechanical ventilation. Research is underway to determine which combination of interventions is most effective in reducing these rates 23…”

Strategies to prevent ventilator-associated pneumonia, ventilator-associated events, and nonventilator hospital-acquired pneumonia in acute-care hospitals: 2022 Update

“…Possible strategies to prevent nosocomial viral transmission include symptom screening of patients and healthcare workers, surveillance testing of all admitted patients, transmission-based precautions for patients with suspected and confirmed respiratory viral infections, universal masking when respiratory virus transmission rates are high in the hospital or in the community, assuring adequate ventilation, and vaccination of healthcare personnel and patients. 312,313 Bundles 1. Multiple observational studies have reported lower NV-HAP rates after implementing prevention bundles.…”