• Antisepsis is the use of chemical solutions for disinfection
• Asepsis is the absence of infectious organisms
• Aseptic techniques are those aimed at minimising infection
• Asepsis usually involves
  • The use of sterile instruments
  • The use of a gloved no touch technique
• Antisepsis is the removal of transient microorganisms from the skin and a reduction in the resident flora

History

• 1847 - Semmelweis identifies surgeons hands as route of spread of puerperal infection
• 1865 - Lister introduces hand and wound asepsis with the use of carbolic acid
• 1880 - von Bergmann invents the autoclave

Preoperative skin preparation

• Bacterial flora of the patient is the principle source of surgical wound infection
• Focal sources of sepsis should be treated prior to surgery
• In patients with active infection consideration should be given to delaying surgery
• Pre-operative showing with an antiseptic solution does not reduce infection rate

Skin shaving

• Aesthetic and makes surgery, suture and dressing removal easier
• Wound infection rate lowest when performed immediately prior to surgery

• Infection rate increased from 1% to 5% if performed more than 12 hours prior to surgery

• Abrasions can cause colonisation which can lead to wound infection
• Clippers or depilatory creams reduce infection rates to less than 1%.

Skin preparation

• 70% Isopropyl alcohol
  • Acts by denaturing proteins
  • Is bactericidal but short acting
  • Effective against gram-positive and gram-negative organisms
  • Also fungicidal and virucidal
• 0.5% Chlorhexidine
  • Quaternary ammonium compound
  • Acts by disrupting the bacterial cell wall
  • Bactericidal but does not kill spore forming organisms
  • It is persistent and has a long duration of action (up to 6 hours)
  • More effective against gram-positive organisms
• 70% Povidone - iodine
  • Acts by oxidation / substitution of free iodine
  • Bactericidal and active against spore forming organisms
  • Effective against both gram-positive and gram-negative organisms
  • Rapidly inactivated by organic material such as blood
  • Patient skin sensitivity is occasionally a problem
  • No evidence that one is superior to any other

Occlusive adhesive drapes

• No evidence that they reduce infection rate
• May actually increase skin bacterial count during surgery

Surgical instruments

• Surgical instruments are prepared by:
  • Cleaning
  • Disinfection
  • Sterilisation

Surgical preparation

• Preoperative washing with bactericidal agent eliminates transient skin flora
• Brush should be used on the nails but not on the skin
• Nail brushing should only be performed once in a surgical session
• Scrub time makes little difference to the incidence of wound infections
• Most surgical gloves are made of latex and are disposable and single-use
• 50% of gloves are punctured during surgery
• Glove perforation increases the risk of wound infection by a factor of five
• Double gloving affords better protection to the surgeon
• Masks protect the surgeon
• There is no evidence that masks reduce the incidence of wound infections

Bibliography

de Lalla F.  Surgical prophylaxis in practice.  J Hosp Infect 2002;  50(Suppl A): S9 - S12. 

Edwards P S,  Lipp A,  Holmes A.  Preoperative skin antiseptics for preventing surgical wound infections after clean surgery.
Cochrane Database Syst Rev. 2004 (3):CD003949.

Lipp A,  Edwards P.  Disposable surgical face masks for preventing surgical wound infection in clean surgery.
Cochrane Database Syst Rev 2002 (1):CD002929.

Webster J,  Osborne S.  Preoperative bathing or showering with skin antiseptics to prevent surgical site infection.  Cochrane Database Syst Rev 2006 (2):CD004985.

Webster J,  Osborne S.  Meta-analysis of preoperative antiseptic bathing in the prevention of surgical site infection.  Br J Surg 2006:  93:  1335-1341.