title: Empirical antimicrobial therapy for probable v. directed therapy for possible ventilator-associated pneumonia in critically injured patients.
abstract: BACKGROUND
  Ventilator-associated pneumonia (VAP) has recently been classified as possible or probable. Although direct attributable mortality has been difficult to prove, delay in instituting appropriate therapy has been reported to increase morbidity and mortality. Recent literature suggests that in possible VAP, instituting directed therapy while awaiting microbiological culture does not prejudice outcome compared with best-guess empirical therapy.
  
  
  OBJECTIVE
  To ascertain outcomes of directed v. empirical therapy in possible and probable VAP, respectively.
  
  
  METHODS
  Endotracheal aspirates were obtained from patients with suspected VAP. Those considered to have possible VAP were given directed therapy following culture results, whereas patients with more convincing evidence of VAP were classed as having probable VAP and commenced on empirical antimicrobials based on microbiological surveillance.
  
  
  RESULTS
  Pneumonia was suspected in 106 (36.8%) of 288 patients admitted during January - December 2014. Of these, 13 did not fulfil the criteria for VAP. Of the remaining 93 (32.2%), 31 (33.3%) were considered to have probable and 62 (66.7%) possible VAP. The former were commenced on empirical antimicrobials, with 28 (90.3%) receiving appropriate therapy. Of those with possible VAP, 34 (54.8%) were given directed therapy and in 28 (45.2%) no antimicrobials were prescribed. Of the latter, 24 recovered without antimicrobials and 4 died, 3 from severe traumatic brain injury and 1 due to overwhelming intra-abdominal sepsis. No death was directly attributable to failure to treat VAP. No significant difference in mortality was found between the 34 patients with possible VAP who were commenced on directed therapy and the 31 with probable VAP who were commenced on empirical antimicrobials (p=0.75).
  
  
  CONCLUSIONS
  Delaying antimicrobial therapy for VAP where clinical doubt exists does not adversely affect outcome. Furthermore, this policy limits the use of antimicrobials in patients with possible VAP following improvement in their clinical condition despite no therapy.
authors.affiliation: Department of Medical Microbiology, Prince Mshiyeni Memorial Hospital, Durban, South Africa; Department of Medical Microbiology, School of Laboratory Medicine and Medical Sciences, College of Health Sciences, Nelson R Mandela School of Medicine, University of KwaZulu-Natal, Durban, South Africa; National Health Laboratory Service (KZN Academic Complex), Durban, South Africa. yogandree@gmail.com.
authors.forename: Yogandree
authors.initials: Y
authors.lastname: Ramsamy
authors.forename: David James Jackson
authors.initials: DJ
authors.lastname: Muckart
authors.forename: John L
authors.initials: JL
authors.lastname: Bruce
authors.forename: Timothy Craig
authors.initials: TC
authors.lastname: Hardcastle
authors.forename: Khine Swe Swe
authors.initials: KS
authors.lastname: Han
authors.forename: Koleka Patience
authors.initials: KP
authors.lastname: Mlisana