Preliminary model assessing the cost-effectiveness of preoperative chlorhexidine mouthwash at reducing postoperative pneumonia among abdominal surgery patients in South Africa. oleh Mwayi Kachapila, Adesoji O Ademuyiwa, Bruce M Biccard, Dhruva N Ghosh, James Glasbey, Mark Monahan, Rachel Moore, Dion G Morton, Raymond Oppong, Rupert Pearse, Tracy E Roberts, NIHR Global Health Research Unit on Global Surgery, ASOS Investigators, STARSurg Collaborative