Anesthesia: Monitoring

An animal under anesthesia should maintain a heart rate that is within 30% of its resting heart rate.

2%

Check for jaw tone/anal tone, appearance of 3rd eyelid, squeeze toes, medial canthus of the eye

Doppler

When it pumps from the ventricles to the rest of the body.

Systolic, diastolic, MAP

Systolic = the number produced by contraction of the LEFT VENTRICLE; all BP monitoring instruments can measure this.

Diastolic = pressure that remains in the arteries when heart is in resting phase between contractions; not all BP monitoring instruments can measure this.

Mean Arterial Pressure; the average pressure throughout the cardiac cycle.

Pressure Transducer

Readings are obtained via a catheter inserted into an artery, providing continuous readings throughout the cardia cycle (most accurate but most invasive)

External cuff placed over an artery, using doppler method.

Doppler & oscillometric

Systolic

Sinus node activity is activated>AV node is stimulated>Atrial contraction>impulse travels within the AV bundle branches to the Purkinje fibers>the impulse is distributed by the Purkinje fibers and relayed throughout the ventricular myocardium=Atrial contraction completed, leads to ventricular contraction.

P wave, PR interval, QRS complex, ST segment, T wave

the 1st wave; precedes atrial contraction; rounded, appears double humped in large animals (bifid); measured from point it leaves baseline to point it returns to baseline.

Represents the time required for the impulse to move from the sinoatrial node to the Purkinje fibers; measured from the beginning of the P wave to the beginning of the QRS complex.

Represents contraction of ventricles; largest waveform, pointed; points up (positive) in small animals; points down (negative) in large animals; measured from the point it leaves the baseline to the point it returns to the baseline.

Located between the QRS complex and the T wave; should leave the baseline only slightly, if at all.

Represents repolarization of ventricles in preparation for the next contraction; measured from the end of the ST segment to the point it returns to the baseline.

Sinus arrhythmia

Dogs

Every 5 minutes

Sometimes it can be based on position of the patient, or the cuff may be loose or the wrong size.

Pulse oximeter

Saturation of oxygen

It utilizes infrared wavelength light technology with digital readout while the probe is placed on the patient's tongue.

Patient safety and anesthetic depth regulation

Stage I, Stage II, Stage III (Plane 1, Place 2, Plane 3) Stage IIII

(1) LIGHT anesthesia (2) SURGICAL anesthesia (3) DEEP anesthesia

Stage III Plane 2: SURGICAL anesthesia

Stage IIII Anesthetic overdose

Animals are NOT in conscious control of their actions; make this stage as short as possible.

Muscle relaxation, decreased RR, decreased reflexes

Stage III Plane 3: we don't usually want a patient to reach this phase, unless it is for a surgery that can be extremely painful.

Little to no RR/HR, circulatory collapse, death

BP: Systolic (90-160); Diastolic (50-90); MAP (70-99)

Sao2: 95-99%

ETCO2: 35-45mmHg

Arterial Oxygen Saturation, normal is between 95-99%

End-tidal carbon dioxide level, normal is 35-45 mmHg

Vital signs, reflexes, movements/muscle tones

Spontaneous movements, chewing on tube, salivation

Excessive anesthetic depth, adverse drug reactions.

Use reversal agents or Atropine to speed up heart rate

Not deep enough anesthesia, adverse drug reactions, pain stimulation.

Treat according to what is causing the fast heart rate.

A delay of the electrical impulse conduction through AV node.

Uncoordinated, small muscle contractions within atria and ventricles.

Atrial & Ventricular fibrillation

Absence of P waves, irregular ventricular rate

Undulating baseline absence of QRS complex, chaotic electrical activity unassociated with organized contraction of the heart muscle.

Cessation of heart contractions, or palpable pulse in presence of normal ECG

The forced transfer of gases, pushing gas out and sucking it back in; no chemical change from oxygen to carbon dioxide; the machine is breathing for the animal.

The animal breathes on its own, and their body chemically uses the oxygen and expels the CO2, naturally breathing.

How small/large of a breath the patient takes; the deeper breath they take, the larger the tidal volume is.

Which type of breath the patient is taking; deep, shallow, labored, shaky.

Alerts if the patient is holding their breath or doesn't breathe for a certain amount of time.

A sensor that sits between the patient and machine, attaches to the ET tube; measures the RR and the CO2 they are breathing out.

Because it measures the amount of CO2 at the END of each breath

Hypercapnia & Hypocapnia

Increase in ETCO2 value; HYPOVENTILATION. Increase respiratory rate

Decrease in ETCO2 value; HYPERVENTILATION. Decrease respiratory rate.

Too deep under anesthesia, positioning, airway obstruction.

Placement of the eye itself; apply eye drop, for example, see if eye itself responds to liquid. usually only used if patient is suspected to be too deep under anesthesia.

"Blink" reflex, touch the corner of the eye, watch for movement/reaction

Pupils should constrict or dilate depending on it light is shown into the eye or not, both eyes should respond the same as the other.

Heart rate & heart rhythm

Normal MM coloring

Every 15-30 minutes manually with a rectal thermometer

Age, size, type of procedure (open surgery, etc.)

Hypothermia

Slows metabolism (more drugs needed), leads to CNS depression, leads to heart malfunction

Warm IV fluids for cavity flush, avoid cold environment/room/tables, barrier between patient and table, forced warm air blanket

Reported as: Present, Decreased, Absent

Palpebral, pedal, laryngeal, pupillary light reflex, corneal, swallowing

The SA node has a cluster of cells that are situated in the upper part of the right atrium wall where electrical impulses are generated.

It displays the electrical impulses generated by the cardiac conduction system that indicated each heartbeat. The monitor generates real time tracing of heart rhythm.