Anaesthesia and associated infection: an unrecognized source

Hospital acquired infections (HAIs) are preventable diseases and place anenomrous socio-economic burden on economy. It is well established that intensive care units (ICU) are epicenters of cross infections and bacterial resistance, but a little is known about the role of anaesthesia atmosphere in this process. Intraoperative environment due to several reasons serves as risk factor for HAIs.^[1-3] Immune suppression associated with general anaesthesia, aerosolized particles and healthcare tools used within the anaesthesia workstation area, may also be linked with development of HAIs ^[4]. There is high probability of patient contamination during the practice of anaesthesia due to rapid patient care combined with frequent contact with potential sources of bacterial transmission. HAIs are more common in countries with poor socioeconomic status where disposable or single use only items are re-used many times. Hospital acquired infections caused by various infectious organisms including bacteria, virus, fungi and parasites, all of which flourish on suitable reservoirs, such as medical equipment.

Precautions are recommended for all patients regardless of their diagnosis or presumed infectious status when there is a possibility of contact with blood, body fluids, non-intact skin and mucus membranes. Preventive measures should be based on the likelihood of an infectious agent being present, the nature of the agent and possibility of dispersion. A standard set of precautions should be established for every invasive procedure with additional risk assessment of each patient.

FACTOR RESPONSIBLE FOR CROSS INFECTION

Intravascular catheter

Stopcocks used for injection of medication, administration of intravenous (IV) infusions, and collection of blood samples represent a potential portal of entry for microorganism into vascular access catheters. Stopcocks should be capped when not being used. “ Piggyback” systems (a side port on a primary infusion set) are used as an alternative to stopcocks but also have risk of infection. Modified piggyback systems have the potential to prevent contamination at these sites. Use of needleless connectors or mechanical valves appears to be effective in reducing connector colonization as compared with standard stopcocks. To reduce intravascular catheter related infection change needleless components of catheter at least every 72 hour, minimize leaks and breaks in the system, scrubbing the access port with an appropriate antiseptic and accessing the port only with sterile devices.

Contamination of drugs

Drugs and fluids need safe handling by anaesthesiologist and should follow protocols for preparation and administration to prevent contamination. Infusion setswith side port (preferably needle-free Luer injection devices)for drug administration and self-collapsible intravenous fluid bags, so no need of air venting which prevent entry of air born infectious particles into fluids. Connection and injection ports in intravenous lines should be kept least. Prepared syringes and needles should be kept in a clean sterile container and capped. Care must be taken when drawing drugs. Single used ampules should be discarded after required amount of drug is drawn up and not re-used for next patients. Syringes and needles must not be used for multiple patients once connected to a patient’s vascular lines or infusions. Injection port kept free of blood and covered with a cap when not in use. After use all syringes and needles should be discarded into an approved sharp container.

Unsafe use and disposal of sharps

Inadvertent injury or inoculation with infected blood is an occupational hazard and present a significant risk to anaesthesiologist. These are mainly caused by needles during venipuncture, drug administration and during recapping of needles. These should be prevented by adhering to guidelines and standards regarding this. Sharps must not be transferred between personnel and handling should be kept minimum. Needle must not be bent or broken prior to use or disposal.

Movement within the theater complex

Restricted movement in and out of operating theater reduces airborne contamination. Door should be closed and eatable items should not be allowed inside O. T complex. Patient’s dress should be changed before transferring to O. T complex. Visitors should change into theater suits and wear designated footwear.

Order of patients

Patients likely to disperse microbes and at risk to others should be scheduled last in the operating list. In between successive patients, transmissions of infection are airborne or on surfaces and object that have been contact with patients. Cleaning of the operating theater between all patients should be undertaken. When there is visible contamination with blood or others body materials, the area must be disinfected according to local protocols and then cleaned with detergent and water. Floors of the operating room should be disinfected at end of each session.

Anesthetic equipment

Either by direct contact with patients or indirectly via splashing, by secretion or from handling anaesthetics equipment may become contaminated. All used equipment’s or its parts must be assumed to be contaminated and disposed of or, if reusable, undergo a process of decontamination. Areas of anaesthetics machine and monitoring equipment which are touched by gloved hand that has been in contact with blood or secretion, should be regarded as contaminated and should be cleaned as early as possible. Equipment that touches intact skin or not touches the patient at all but visibly contaminated is cleaned at the end of day or whenever visibly contaminated. This includes non-invasive blood pressure cuffs and tubing, pulse oximeter probes and cables, stethoscopes, electrocardiographic cablesetc.

Oxygen mask and tubing should besingle-patient use products. If reused it must be cleaned and sterilized if possible or according to manufacturer’s instructions. Anaesthetic face masks are usually in contact with intact skin; these are frequently contaminated by secretions from patients and have been implicated in causing cross infection.^[5] Airways and tubes readily contaminated with transmissible organism and blood and should be single-use type.^{[6, 7]} Supra-glottic airways commonly used are re-usable design; therefore they should be sterilized but no more often than the manufacturer recommends. A supraglottic airway used for tonsillectomy or adenoidectomy should not be used again (due to risk of Prion Disease).

Laryngoscope blades are regularly contaminated with blood due to penetration of mucous membranes, which places these items into a high–risk category.^[8] Decontamination and disinfection between patients are ineffective, leaving residual contamination that has been implicated as source of cross infection.^{[9, 10]} So proper cleaning of laryngoscope blades is important before decontamination /sterilization particularly around light sources or articulated section.

ForAnaesthetic machinesManufacturers cleaning and maintenance policesshould be followed, and bellows, unidirectional valves and carbon dioxide absorbers should be cleaned and disinfected periodically. Bacterial/viral filter is used between patient and circuit to prevent air born transmission of microorganism. Surfaces of anaesthesia machines should be cleaned on daily basis with an appropriate disinfectant. Anaesthesia breathing system actsas important reservoir for microorganism if used for longer period or used without filter. It is recommended that an appropriate filter should be placed between the patient and breathing system for each new patient. It is claimed that hydrophobic filters have better performance than most electrostatic filters, the clinical relevance yet to be established.^{[11, 12]} Departments may follow the manufacturer’s recommendations for use but if visibly contaminated or used for highly infectious case, the circuit should be changed between patients and safely discarded.

Bougies re-use has been associated with cross infection.^[13] Gum elastic bougie may be disinfected up to five times or according to manufacturer recommendation and stored in a sealed packet. Preferably single-use intubation aids are employed when possible.

INFECTIOUS COMPLICATION OF REGIONAL ANAESTHESIA

Infectious complication of regional anaesthesia includes abscess formation, necrotizing fasciitis, meningitis, arachnoiditis which can lead to paralysis and death. The rate of spinal- epidural abscess or meningitis occurrence has been reported to be 1: 10000 to 1: 40000.^{[14, 15]} Potential routes might be contaminated syringes, catheter hubs, local anaesthetics or breaches in aseptic technique. The suggested mechanism of hematogenous infection of central nervous system caused by subarachnoid or epidural puncture might be an accidental vessel puncture lead to introduction of blood into the intrathecal space.

Staphylococcus aureus is the organism most commonly associated epidural abscess and often this infection occurred in patient with impaired immunity.

Meningitis follows dural puncture is typically caused by alpha-hemolytic streptococci, with the source of organism the nasopharynx of the anaesthesiologist.^[14]

WHAT IS THENEED?

Anesthesiologist’s are insensitive regarding prevention of infection in anaesthesia atmosphere in many institution of our country. Excessive movement in Operation Theater complex, drug bags or edible items in operative room and poor compliance with cap and mask by anaesthesiologist are also contributing factors. Equipment’s are used repeatedly without cleaning/sterilization e. g. Face mask, ventilator circuit, bougie, tubes etc.

Stress should be given on preventive medicine in medical and nursing curriculum. Irrespective of specialty infection prevention should be a part of the teaching curriculum. Hospital must dedicate time to re-educating and re-training their staff in infection prevention. Various studies shows that, in spite of increase in knowledge scores regarding infection prevention, doctors were least compliant of the HCW in infection control practices.^{[16, 17]}

Early detection with surveillance and screening are the important step in the prevention of hospital acquired infections. Prevention of cross infection is by isolating the affected patients, educating the public/ healthcare professionals, appropriate use of antibiotics, meticuloushand hygiene and appropriate cleaning and decontamination of the environment and medical equipment

Three main techniques are important to prevent infection transmission from provider to the patients. These include aseptic practice, proper hand hygiene, and appropriate barrier techniques are recommended by Centers for Disease Control and Prevention.

References

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