Guidelines

Anesthesia and Sedation Monitoring Guidelines

Unit for Laboratory Animal Medicine
Nov 27, 2019 12:00 am
  1. This document was created by the ULAM veterinary staff as a guideline for anesthesia and sedation monitoring. This is not intended to be an inclusive tutorial on all possible methods and all equipment available for anesthesia monitoring.
    1. Detailed information for species-specific anesthesia and analgesia, are available here.
  2. Contact ULAM veterinary staff (ulam-vets@umich.edu) and/or ULAM training core (ulam-trainingcore@umich.edu) for additional training on these techniques.
    1. If surgical procedures will be performed outside of ULAM-ASOR, the ULAM veterinary staff should be contacted for monitoring equipment recommendations.
    2. If neuromuscular blockade is used, the ULAM veterinary staff will need to be contacted for dosing and monitoring guidance.
  • Responsibility

    1. Principal Investigator: Responsible to ensure appropriate anesthesia, monitoring, and analgesia is provided for all animals undergoing surgical or sedation procedures.
  • Glossary Definitions

    Sedation

    Central depression causing stupor where the animal is unaware of its surroundings but still responsive to painful procedures.

  • Rodent Anesthetic / Sedation Expectations

    1. Rodent Recovery Anesthesia / Sedation & Monitoring

    1. Recovery Anesthesia Expectations
      1. Procedures must meet current veterinary anesthesia standards of care.
      2. Principal Investigators (PIs) are expected to provide anesthesia and monitoring equipment corresponding to the complexity and potential anesthetic complications associated with their research model.
      3. Lab personnel are expected to maintain aseptic technique while providing appropriate anesthetic monitoring during surgery and aseptic procedures. Typically, this requires one person dedicated to the procedure or surgery and a separate person dedicated to anesthesia monitoring.
    2. Anesthetic Evaluation
      1. Once the rodent is anesthetized, the anesthetic depth must be evaluated prior to initiating the procedure. Appropriate anesthetic depth is determined by absence of painful response, such as pedal or toe pinch.
    3. Monitoring
      1. Monitoring is recommended throughout the anesthetic event at minimum every 15 minutes.
      2. Cardiovascular System:
        1. Tail, foot, tongue or ear color can be monitored for pale or blue membranes, which is indicative of decreased blood volume, decreased perfusion or respiratory distress.
      3. Respiratory System:
        1. Small rodents have respiratory rates too quick to accurately count. Instead, an assessment of the breathing pattern should be made. (e.g., regular vs. irregular breaths).
      4. Body Temperature:
        1. Rodents are prone to hyperthermia and hypothermia. 
          1. Warming devices should provide gentle heat only (maximum of 102°F). An insulated pad or folded drape must be placed between the animal and the heat source.
          2. AVOID commercial human electric heating pads, and heating lamps.
        2. See Appendix C for recommended warming devices.

    2. Sedation Without General Anesthesia

    1. Monitoring
      1. Cardiovascular, respiratory, and temperature monitoring guidelines should follow recovery anesthesia monitoring guidelines.
    2. Oxygen should be supplemented by facemask.

    3. Non-Recovery Anesthesia

    1. Pre-Anesthetic Examination
      1. A physical examination should be performed including heart rate and rhythm, mucous membrane color (normal = pink), capillary refill time (normal < 2 seconds), respiratory sounds and rate, and temperature.

    4. Records

    1. Monitoring records must be kept for each animal undergoing any survival procedure. For more information on medical documentation of procedures and surgical monitoring, please refer to Guidelines on Medical Records for Investigative Personnel.
  • Non-Rodent Anesthesia / Sedation Expecatations

    1. Non-Rodent Recovery Anesthesia & Monitoring

    1. Recovery Anesthesia Expectations
      1. Procedures must meet current veterinary anesthesia standards of care.
      2. Principal Investigators (PIs) are expected to provide anesthesia and monitoring equipment corresponding to the complexity and potential anesthetic complications associated with their research model.
      3. Lab personnel are expected to maintain aseptic technique while providing appropriate anesthetic monitoring during surgery and aseptic procedures. Typically, this requires one person dedicated to the procedure or surgery and a separate person dedicated to anesthesia monitoring.
    2. Pre-Anesthesia Evaluation and Anesthetic Depth Assessment
      1. A physical examination should be performed including: heart rate and rhythm, mucous membrane color (normal = pink), capillary refill time (normal <2 seconds), respiratory sounds and rate, and temperature. It is recommended to perform the following baseline clinical chemistries: packed cell volume (PCV) or hematocrit, total protein, glucose, blood urea nitrogen (BUN), and serum creatinine.
      2. Adequate anesthetic depth must be evaluated prior and during anesthetic period. It can be assessed by the following:
        1. Loss of response to stimulation including toe, ear, or tail pinch
        2. Loose mandibular jaw tone
        3. Absent blink reflex
        4. Eye position – central eye position indicates depth of too deep or too light
          1. Non-ruminants – Eyes rotate rostroventrally
          2. Ruminants – Eyes rotate ventrally and only sclera is seen
    3. Monitoring
      1. Monitoring must be performed throughout the anesthetic episode with documentation at least every 15 minutes and until the animal is ambulatory. Examples of devices for monitoring can be found in Appendix D.  Minimal monitoring requirements include:
      2. Cardiovascular System:
        1. Heart rate or pulse rate must be monitored
          1. Heart rate can be monitored by palpating the chest wall, placement of an esophageal stethoscope, or use of a standard stethoscope.
          2. Pulse rate can be monitored by palpating a pulse on the extremities or through monitoring equipment such as a doppler ultrasound, pulse oximetry or direct arterial blood pressure.
          3. An electrocardiogram can be used in conjunction with pulse oximetry or palpation to assess cardiac rhythm or detect cardiac dysrhythmias.
        2. Peripheral perfusion must be assessed by capillary refill time (normal < 2 seconds) or mucous membrane color (normal = pink).
        3. Blood pressure monitoring is highly recommended.
          1. Invasive or noninvasive methods are available.
        4. Pulse Oximetry: Non-invasive method to accurately measure peripheral capillary oxygen saturation (SpO2) along with pulse rate.
          1. Best if placed on the non-pigmented, non-haired regions of the body: tongue, ear, or commissures of the mouth.
          2. Ideal SpO2 > 95%
            1. SpO2 < 90% = hypoxia
        5. Arterial Blood Gas
          1. For thoracic, cardiovascular, or neurologic procedures, serial arterial blood gas sampling is highly recommended.
        6. Electrocardiograph (ECG)
          1. ECGs are recommended if dysrhythmias are expected secondary to surgical procedure or clinical condition.
      3. Respiratory System:
        1. Respiratory rate must be monitored.
          1. Respiratory rate can be assessed by visually counting chest wall inflations, utilizing a stethoscope, monitoring rebreathing bag movements, or by appropriate monitoring equipment such as mechanical ventilation bellows or capnography.
        2. Capnography (End-tidal CO2 - ETCO2)
          1. Ideal range of ETCO2 for non-rodents under anesthesia is 35-50 mmHg.
      4. Body Temperature:
        1. Body temperature must be monitored during anesthesia and recovery to prevent serious changes from normal. Thermal support should be supplemented depending on species, procedure, and duration of procedure.
          1. Warming devices should provide gentle heat only (maximum of 102°F). When using a heating pad, an insulated pad or folded drape must be placed between the animal and the heat source.
          2. AVOID commercial human electric heating pads, and heating lamps.
          3. See Appendix C for recommended warming devices for non-rodents
    4. Records:
      1. Monitoring records must be kept for each animal undergoing any anesthetic procedure. For more information on medical documentation of procedures and surgical monitoring, please refer to Guidelines on Medical Records for Investigative Personnel.

    2. Sedation Without General Anesthesia

    1. Monitoring
      1. Cardiovascular, respiratory, and temperature monitoring guidelines should follow the recovery anesthesia monitoring guidelines.
    2. Oxygen should be supplemented by facemask. For heavy sedation, intubation equipment (laryngoscope and endotracheal tube) should be available in case protective airway reflexes are lost.

    3. Non-Recovery Anesthesia Event

    1. Pre-Anesthetic Examination: A physical examination should be performed including heart rate and rhythm, mucous membrane color (normal = pink), capillary refill time (normal < 2 seconds), respiratory sounds and rate, and temperature.
    2. Records: Cardiovascular, respiratory, and body temperature monitoring guidelines should follow the recovery anesthesia monitoring guidelines.
  • Appendix A: Rodent Anesthetic / Sedation Monitoring

  • Appendix B: Non-Rodent Anesthetic / Sedation Monitoring

  • Appendix C: Heating / Warming Devices

  • Appendix D: Monitoring Devices