SARS感染患者麻醉管理指南：Proposed Guidelines: Anesthetic Management of a SARS

华西小卒

Proposed Guidelines: Anesthetic Management of a SARS - Infected Patient

Background

Prepared May 7, 2003

Severe Acute Respiratory Syndrome (SARS) is an infection in which affected individuals develop a fever, followed by respiratory symptoms such as cough, shortness of breath or difficulty in breathing. In some cases, the respiratory symptoms become increasingly severe, leading to respiratory failure, ventilatory dependency and occasionally, death. The causal pathogen is believed to be a novel coronavirus, thought to be spread by "droplet / contact".

It is possible that a patient with SARS may require therapeutic / diagnostic procedures which require the presence of an anesthesiologist. Evidence from the recent outbreak of SARS in Toronto, suggests that anesthesiologists (and other health care workers) exposed to oral secretions at the time of intubation are at 'high risk' of acquiring the infection.

To this end, the following are recommendations for the anesthetic management of a SARS patient (probable / "person under investigation"). The principles and a protocol for managing these patients (outlined below) have been developed by anesthesiologists at six hospitals affiliated with the University of Toronto. It should be emphasized that these recommendations are based on our current understanding of this illness and its spread. These recommendations are expected to change over time. Although this is presented as a single document, it has been modified in each of the hospitals affiliated with the University of Toronto to meet local needs and available resources. The SARS experience has alerted the anesthesia community to the need to review and revise our current infection control practices for all patients in the operating room. New guidelines for infection control for all patients are anticipated in the near future.

Of the recommendations listed below, the use of Personal Protection Systems may be the most unfamiliar to anaesthesiologists. Hospitals are recommending the use of personal protection hoods and suits for physicians and assistants involved in laryngoscopy or other airway interventions (including extubation). Devices such as the Powered Air Purifying Respirator system consist of a lightweight hood (e.g. PAPR hood device) connected via a breathing tube, to a belt-mounted air purifier. Other hospitals have purchased the Stryker "T4 Personal Protection System" that also filters air. No clear consensus has been reached regarding the best air filtration system. Nevertheless, these systems are considered to be important barriers to protect health care personnel during larygoscopy, intubation, and other invasive airway procedures. Importantly, caregivers need to be trained in the use of these suits in advance of airway intervention. Procedures for safely removing contaminated suits, gloves, boots and outer gowns must also be reviewed. Gloves should be removed and replaced after intubation before touching any equipment. Detailed protocols for the use of this equipment are being developed.

1. General OR management of potential SARS patient

i) Patient transfer

• Patients must be transferred directly into the OR
• Transfer route (to OR) should be discussed with 'Infection Control' team member Patients must wear a face mask (N95).
• Transporters should adopt full droplet /contact precautions (see below)
• Assistance (respiratory therapist) should be provided for the anesthesiologist.
• Ambubags should be equipped with a small-volume heat and moisture exchange filter (e.g. PAL filter)

ii) Staff precautions

• Staff should wear clean surgical scrubs laundered by the hospital (no personalized hats!)
• Minimize the number of individual staff members present. There should be minimal exchange of staff during the cas
• Hand-washing (e.g. With Cida Rinse) for 15 seconds before and after patient care.
• Communicate with all levels of staff, involved in the patient's care regarding the patient's SARS status.
• Clear the room of unnecessary or over stocked equipment.
• Post a "Droplets/ Contacts" sign on the OR doors to minimize traffic. Keep doors closed.

iii) On entry to the OR

• maintain full droplet /contact precautions: - Gowns (front and back protected)
• Double glove. Remove first pair after providing direct patient care and before touching other areas of the room/ anaesthesia machine. Subsequent intervention must be performed with double gloves.
• N95 or PCM2000 mask or equivalent must be worn. Ensure that there is an adequate seal (Beards interfere with seal)
• A full face disposable plastic shield for eye protection. Neither protective eye wear (such as goggles) nor prescription glasses are adequate.
• It is recommended that (where possible), staff stay a minimum of 2 meters from the patient to avoid droplet contamination.

Hospitals are recommending the use of personal protections hoods and suits for physicians and assistants involved in laryngoscopy or other airway interventions (including extubation). Devices such as the Powered Air Purifying Respirator system consists of a lightweight hood (e.g. PAPR hood) connected via a breathing tube, to a belt-mounted air purifier. Other hospitals have purchased the Stryker "T4 Personal Protection System" that also filters air.

At the end of the case

• Remove gloves, followed by gown and decontaminate hands with alcohol (Cida) hand rinse for 15 seconds.
• Remove face shield, followed by hair cover and wash hands again. Remove goggles, then mask and wash hands again with alcohol (eg. Cida) rinse for 15 seconds. Re-gown, glove, put on hair cover, mask and goggles.
• Transfer patient directly to Post-anesthesia Care Unit (isolation room)
• Remove gown, gloves, goggles and mask prior to exiting the isolation room.
• Change surgical scrub suit as soon as practically possible.

NOTE: Directives from the Ministry of Health require that a 'SARS Unit' be a negatively pressurized room, which is not available in most ORs (typically positively pressurized with filtration to the incoming ventilation system). Some hospital protocols advocate that intubation be performed in negative pressure rooms where available.

2. Anesthesia equipment

Filters

Correct use of the small-volume heat and moisture exchange filter (eg. PAL filter) provides bacterial/ viral removal greater than 99.999%. It has a hydrophobic membrane that block the passage of bodily fluids and aerosolized droplets (carrying pathogens).

Anesthetic Circuits

Circle circuit: Use a disposable circle system, reservoir bag and mask as well as BP cuff and temperature probe (all found on the SARS cart); A PAL filter should be placed on the inspiratory and expiratory limbs of the circuit. The PAL filter should be discarded, with the circuit, reservoir bag and tubing, at the end of the case. Place another filter at the machine end of the fresh gas flow outlet. Continue to use the gas-scavenging device as usual.

Soda lime

The Soda lime does not need to be changed but the end-tidal C02 sample line with trap must be changed after the case.

Drug Cart

Prior to patient arrival, remove from the cart what you consider necessary for the entire case and place it at least 2 meters from the operating table. During the case, avoid contamination of the cart by either double gloving (double glove for patient contact /single glove for cart contact) or requesting a colleague (not touching the patient) to obtain what you need from the cart.

Machine /surfaces

Place the anesthetic machine as far from the patient as practically possible. Consider using a surface away from the anesthetic machine for placement of contaminated equipment (eg laryngoscope). Discard needles and syringes immediately.

3. Anesthetic technique

General aim to minimize patient coughing before, during and after intubation and/or induction of anesthesia.

Choice of Airway

• Cuffed endotracheal tubes.
• LMA's are permitted (may be preferred to reduce airway irritation) if appropriate considering patient's respiratory status.

Discard LMA or endotracheal tube after use, along with oral and nasal airways.

Choice of Anesthetic

Tailor to the patients' needs.

Monitoring

Use axillary temperature probes. Avoid nasal or esophageal probes.

4. Cleaning of anesthesia equipment

No additional measures have been implemented for the cleaning of anesthesia equipment. However particular attention should be focused on the exterior surfaces of the anesthesia machine (including dials / vaporizers), ventilator and laryngoscope handles. Disinfection with a hospital-approved agent, (eg. virox) should be used.

5. Laboratory specimens

• Communicate with laboratories FIRST before sending samples. Indicate "SARS SPECIAL INVESTIGATION" on form.
• Do not send specimens in the pneumatic tube. Send in biohazard bags, in biohazard screw top bottles and have hand delivered to the lab.

Policy for emergency tracheal intubation of SARS patients outside the OR

When patients with suspected SARS require tracheal intubation, the Intensive Care or Emergency Department Staff physician may request the assistance of the On-Call Staff Anesthesiologist. As for all patients, a careful assessment of the airway should be performed and the possibility of difficulty during intubation anticipated before an urgent airway intervention is required.

Pagers

The On-Call staff Anesthesiologist can be located via the Hospital Switchboard or OR desk.

Equipment Available in the ICUs and SARS units

• Manual resuscitation bag with viral filter
• In-line suction catheters
• PAPR hoods*
• Intubation equipment*
• Anesthesia and Resuscitation drugs*

The top of the Cardiac Arrest cart will contain 3 additional packages

• PAPR hoods (2 - for anesthesiologist and RT)
• Intubation equipment (laryngoscope, ETT 7.0, 8.0 mm, oral airway, Yankauer sucker, stylette, ties/tape, PAL filter)
• Drugs/Syringes - (midazolam 5 mg, succinylcholine 200 mg, rocuronium 100 mg, ephedrine 50 mg, atropine 0.6 mg). Syringes 1- 20 ml, 3 - 10 ml, and 3 - 5 ml. Injection port adaptor.

Procedure

• After hand-washing, both Intubator and RT will put on double gloves, gowns, goggles, boots and PAPR hoods or Stryker hoods in the ante-room or outside the patient's room.
• Intubation will preferably be performed in patients who are sedated (midazolam) and paralysed (succinylcholine or rocuronium) to prevent coughing, and facilitate the intubation.
• After intubation, the gowns, boots, hoods, and gloves will be removed in the ante-room or inside the patient's room, first by the RT who will then assist the anesthesiologist.

List of drugs stocked in a separate SARS intubation kit

TOP SHELF (Intubation Medications)	QUOTA
Atropine 1mg/10ml	1
Ephedrine 50mg	1
Glycopyrolate 0.2mg	1
Ketamine 100mg	1
Midazolam 5mg/5ml	1
Narcan 0.4 mg/1 ml	1
N/S 250cc	1
Propofol 200mg	1
Succinylcholine 100mg	1
Rocuronium 50 mg	1
BOTTOM SHELF (Cardiac Medications)
Adenosine 6mg/2ml	1
Amiodarone 150mg/3ml	2
Atropine 1mg/10ml	2
Calcium Chloride 1gm/10ml	1
D50W 25gm/50ml	1
Diltiazem 50mg/10ml	1
Epinephrine 1mg/10ml 1:10,000	3
Lidocaine 100mg/5ml	2
Magnesium Sulphate 5gm/10ml	1
Metoprolol 5mg/5ml	1
Sodium Bicarbonate 50mEq/50ml	1
Verapamil 5mg/2ml	1