• The word anesthesia means without sensation-–our goal is to provide unconsciousness, amnesia, analgesia and muscle relaxation
for a variety of procedures both invasive and non-invasive. Our ability to carefully string our patients out along the line
between life and death compromises homeostasis making close monitoring essential.
Why monitor?
• Anesthetic emergencies are difficult to predict
• Anesthetic emergencies happen quickly
• Anesthetic emergencies can be devastating
• It is better to be proactive rather than reactive
Our goal
• To be able to walk that line with confidence by maximizing the safety of the anesthetic experience
Morbidity and mortality (M&M)
• Morbidity refers to the prevalence of disease (related to the anesthetic event in this case)
• Mortality refers to the chances of death
• Certain problems are more likely to increase M&M
o Excessive bradycardia
o Cardiac depression
o Vasodilation
o Hypotension
o Arrhythmias
o Hypoventilation
o Hypoxemia
o Hypothermia
• Diligent monitoring allows us to recognize and treat potentially life threatening problems
Monitoring basics
• If you only had eyes, ears and hands...
o Heart rate
o Pulse quality and vasomotor tone
o Respiratory rate and character
o Reflexes and muscle tone
o Eye position
o Body temperature
• Monitoring multiple parameters gives you a more complete picture of the physiologic status of the patient
Heart rate
• Stay away from extremes...
• Bradycardia
o Heartrate is too slow when it is associated with decreased cardiac output, hypotension and/or poor perfusion
o Dog low 50's (with normal BP- also dependent on size, small dogs have higher heart rates...)
o Cat low 100's (with normal BP)
o It is also important to monitor blood pressure (BP) and end-tidal carbon dioxide (ETCO2)
• Tachycardia
o Decreases filling time of ventricle and increases myocardial oxygen consumption- a double whammy!
o Dogs 180-200 (size dependent)
o Cats 240-280 (size dependent)
• Some cause of extremes of heart rate (and potential ways to remedy them)
o Bradycardia
• Anesthetic overdose (lighten up)
• Opioid administration (give an anticholenergic)
• Alpha-2 agonist administration (reverse or no treatment)
• Hypothermia (rewarm)
• Hypoxia (oxygen therapy)
• 1st and 2nd degree A-V blockade (anticholenergics)
• High vagal tone (anticholenergics)
