What are the indications for Chlorhexidine (antiseptic) and what is the recommended duration of use?

Chlorhexidine Indications and Duration of Use

Chlorhexidine in alcohol should be used as the antiseptic of choice for skin preparation before central neuraxial blockade (CNB) and peripheral nerve blocks, with 0.5% concentration being the preferred option to balance antimicrobial efficacy and safety. 1

Indications for Chlorhexidine

Primary Indications:

• Skin antisepsis before invasive procedures:
  • Central neuraxial blockade (spinal/epidural anesthesia) 1
  • Peripheral nerve blocks 1
  • Central venous catheter insertion 1
  • Surgical site preparation 2

Other Clinical Applications:

• Infection prevention:
  • Hand hygiene for healthcare workers 1
  • Preoperative patient bathing/showering (2% or 4% CHG) 2
  • Wound irrigation prior to closure (0.05% concentration) 2
  • Oral hygiene as mouthwash 3, 4
  • Antiseptic for mucous membranes 5
  • Impregnation in catheters to reduce catheter-related bloodstream infections 4

Concentration Recommendations

1. For Central Neuraxial Blockade (CNB):

   • 0.5% chlorhexidine in alcohol is recommended as the optimal concentration 1
   • Provides the safest compromise between infection risk and neurotoxicity risk 1
   • No convincing evidence that 2% solution offers superior antimicrobial effect over 0.5% 1

2. For Hand Hygiene:

   • 2-4% chlorhexidine gluconate preparations are effective 1
   • 4% formulations have greater antimicrobial activity than 2% formulations 1

3. For Preoperative Bathing:

   • 2% or 4% CHG using standardized protocols 2

4. For Wound Irrigation:

   • 0.05% CHG followed by saline rinse 2

Duration of Use

For Single Procedures:

• For skin antisepsis before CNB:
  • Apply and allow to dry completely before proceeding 1
  • Chlorhexidine exerts antiseptic effect for up to 24 hours after application 1

For Indwelling Catheters:

• For epidural catheters:
  • Chlorhexidine maintains antimicrobial activity for at least 24 hours 1
  • Continued antisepsis should be maintained throughout the time the catheter remains in situ 1

For Routine Use:

• Chlorhexidine has substantial residual activity compared to other antiseptics 1
• Addition of low concentrations (0.5%-1.0%) of chlorhexidine to alcohol-based preparations results in greater residual activity than alcohol alone 1

Application Method for CNB

1. Use pre-soaked antiseptic sponge applicators ('swab-sticks') rather than pouring into containers 1
2. Allow solution to dry completely before skin palpation or puncture 1
3. Keep antiseptic well away from drugs and equipment to be used for the procedure 1
4. Cover equipment while applying antiseptic 1
5. Check gloves for contamination with chlorhexidine and change if necessary 1

Special Populations

Children Under 2 Months:

• Use minimum necessary volume while ensuring antisepsis 1
• Chlorhexidine products are not FDA-approved for children younger than 2 months of age 1
• Despite this, chlorhexidine is commonly used in neonatal ICUs for central venous access 1

Safety Considerations and Adverse Effects

Neurotoxicity:

• Chlorhexidine is neurotoxic if it reaches the cerebrospinal fluid 1
• Meticulous technique is required to prevent contamination of needles and equipment 1

Allergic Reactions:

• Range from mild irritant contact dermatitis to life-threatening anaphylaxis 3
• Most anaphylaxis cases involve mucous membrane application or chlorhexidine-impregnated devices 1
• Allergic contact dermatitis can precede anaphylaxis 3

Other Adverse Effects:

• Contact with eyes can cause conjunctivitis and severe corneal damage 1
• Ototoxicity precludes use in surgery involving inner or middle ear 1
• Direct contact with brain tissue and meninges should be avoided 1
• Skin irritation is concentration-dependent (4% most likely to cause dermatitis) 1

Antimicrobial Spectrum

• Good activity: Gram-positive bacteria 1
• Somewhat less activity: Gram-negative bacteria and fungi 1
• Minimal activity: Tubercle bacilli 1
• Not effective against: Spores 1
• Effective against: Enveloped viruses (herpes simplex, HIV, cytomegalovirus, influenza, RSV) 1
• Less effective against: Non-enveloped viruses (rotavirus, adenovirus, enteroviruses) 1

Chlorhexidine's antimicrobial activity is minimally affected by organic material, including blood, making it particularly valuable in clinical settings 1.