inclusion criteria: * patients aged 18 years and over. (this criteria must be made country-specific) * planned to undergo abdominal or thoracic elective or emergency inpatient surgery requiring general anaesthesia. * asymptomatic of covid-19, including patients with: those not tested, negative test results, positive test but no symptoms (to be monitored post-surgery for symptoms) * informed patient consent. * able to operate a vibrating mesh nebuliser, as assessed by the recruiting physician

inclusion criteria: * patients aged 18 years and over. (this criteria must be made country-specific) * planned to undergo abdominal or thoracic elective or emergency inpatient surgery requiring general anaesthesia. * asymptomatic of covid-19, including patients with: those not tested, negative test results, positive test but no symptoms (to be monitored post-surgery for symptoms) * informed patient consent. * able to operate a vibrating mesh nebuliser, as assessed by the recruiting physician

inclusion criteria: - patients aged 18 years and over. (this criteria must be made country-specific) - planned to undergo abdominal or thoracic elective or emergency inpatient surgery requiring general anaesthesia. - asymptomatic of covid-19, including patients with: those not tested, negative test results, positive test but no symptoms (to be monitored post-surgery for symptoms) - informed patient consent. - able to operate a vibrating mesh nebuliser, as assessed by the recruiting physician

inclusion criteria: - patients aged 18 years and over. (this criteria must be made country-specific) - planned to undergo abdominal or thoracic elective or emergency inpatient surgery requiring general anaesthesia. - asymptomatic of covid-19, including patients with: those not tested, negative test results, positive test but no symptoms (to be monitored post-surgery for symptoms) - informed patient consent. - able to operate a vibrating mesh nebuliser, as assessed by the recruiting physician

inclusion criteria: - patients aged 16 years and over in the uk. (this criteria must be made country-specific) - planned to undergo any type of elective or emergency inpatient surgery requiring general or regional anaesthesia (such as vulnerable patients undergoing surgery for a fractured neck of femur). - asymptomatic of covid-19, including patients with: those not tested, negative test results, positive test but no symptoms - informed patient consent.

inclusion criteria: - patients aged 16 years and over in the uk. (this criteria must be made country-specific) - planned to undergo any type of elective or emergency inpatient surgery requiring general or regional anaesthesia (such as vulnerable patients undergoing surgery for a fractured neck of femur). - asymptomatic of covid-19, including patients with: those not tested, negative test results, positive test but no symptoms - informed patient consent.