Anesthetic Monitoring Ch.6 Objectives Flashcards
Explain the principles of anesthetic monitoring, including the reasons for and goals of monitoring.
Anesthetic monitoring ensures patient safety and well-being during surgery by continuously assessing vital signs and physiological functions, with the goal of preventing complications and maintaining optimal anesthesia depth
List the physical monitoring parameters, and classify each in one of the following categories: (1) vital signs, (2) reflexes, (3) other indicators of anesthetic depth.
Physical monitoring parameters, classified into vital signs, reflexes, and other indicators of anesthetic depth:
Vital Signs:
Body temperature: Measured using a thermometer, indicates core body temperature
Blood pressure: Measurement of the force exerted by blood against the walls of arteries
Heart rate (Pulse rate): Number of times the heart beats per minute
Respiratory rate (Breathing rate): Number of breaths per minute
Oxygen saturation (SpO2): Percentage of oxygen bound to hemoglobin in the blood
Reflexes:
Pupil light reflex: Contraction of the pupil when exposed to light
Corneal reflex: Blinking in response to touching the cornea
Flexor withdrawal reflex: Withdrawal of a limb in response to painful stimulation
Other Indicators of Anesthetic Depth:
Muscle relaxation: Degree of muscle relaxation during anesthesia
Eye movement: Presence or absence of eye movement, such as nystagmus
Verbal response: Patient’s ability to respond verbally
Electroencephalogram (EEG): Measurement of brain electrical activity
End-tidal CO2 (EtCO2): Concentration of carbon dioxide at the end of a breath, indicating ventilation adequacy
It’s important to note that the specific monitoring parameters used may vary depending on the individual patient, the type of surgery, and the preferences of the healthcare team. Some sources list additional physical monitoring parameters, such as capnography, electrocardiography (ECG), and temperature. These parameters provide valuable information about the patient’s physiological state and can help guide anesthetic management.
List and describe each of the stages and planes of anesthesia.
Under this system, general anesthesia was divided into four stages (I to IV), and stage III was subdivided into four planes (1 to 4) based on eye movement, pupil size, and later eyelid movement
Loss of consciousness marks the border between stages I and II.
* Loss of spontaneous muscle movement marks the border between stages II and III.
* Loss of all reflexes, widely dilated pupils, flaccid muscle tone, and cardiopulmonary collapse mark stage IV.
-During stage I, the patient begins to lose consciousness. This stage is usually characterized by fear, excitement, disorientation, and struggling. The HR and RR increase, and the patient may pant, urinate, or defecate. A patient in stage I is typically difficult to handle. Near the end of stage I, the patient loses the ability to stand and becomes recumbent.
-During stage II, also known as the excitement stage, the patient loses voluntary control and breathing becomes irregular. This stage is usually characterized by involuntary reactions in the form of vocalizing, struggling, or paddling. The HR and RR are often elevated, pupils are dilated, muscle tone is marked, and reflexes are present and in fact may appear exaggerated.
-During stage III, the patient is unconscious and progresses gradually from light to deep anesthesia. This stage is characterized by progressive muscle relaxation, decreasing HR and RR, and loss of reflexes. The pupils gradually dilate, tear production decreases, and the PLR is lost. The increase in HR, BP, and RR seen in response to surgical stimulation during light anesthesia is also gradually lost.
-If anesthetic depth continues to increase, the animal enters stage IV anesthesia. At this stage there is cessation of respiration, and the cardiovascular system is markedly depressed with a dramatic drop in HR and BP, accompanied by pale mucous membranes and a prolonged CRT. If not recognized and managed, circulatory collapse and death will quickly follow. Immediate resuscitation is necessary to save the patient’s life.
List the monitoring parameters used primarily to determine whether or not the patient is safe, and group them according to whether they primarily assess circulation, oxygenation, or ventilation.
To ensure patient safety, monitoring parameters are categorized by their primary function: circulation (heart rate, blood pressure, capillary refill time), oxygenation (SpO2, arterial blood gases), and ventilation (respiratory rate, tidal volume, end-tidal CO2).
Vital signs may be assessed either by physical means (i.e., touch, hearing, and vision) or through the use of various instruments and machines such as an electrocardiograph, BP monitor, capnograph, Doppler blood flow detector, or pulse oximeter.
Explain and demonstrate assessment of each of the vital signs, reflexes, and other indicators of anesthetic depth.
In veterinary anesthesia, assessing vital signs, reflexes, and other indicators helps determine anesthetic depth and ensure patient safety. Key indicators include heart rate and rhythm, respiratory rate and depth, temperature, blood pressure, reflexes like palpebral and corneal, and jaw tone.
List normal values for each physical monitoring parameter, and identify values that should be reported to the attending veterinarian.
Heart Rate (HR) | 60-150 bpm in dogs, 120-200 bpm in cats | HR < 60 or > 150 bpm in dogs, < 120 or > 200 bpm in cats, or any irregular rhythm
Respiratory Rate (RR) | 10-30 breaths per minute in dogs, 15-30 breaths per minute in cats | RR < 10 or > 30 breaths per minute, or labored breathing
Body Temperature | 100.5-102.5°F (38-39°C) | Temperature outside of this range
Blood Pressure | Systolic 90-120 mmHg, Diastolic 55-90 mmHg | Systolic < 90 mmHg or > 120 mmHg, Diastolic < 55 mmHg or > 90 mmHg
SpO2 (Oxygen Saturation) | > 95% | SpO2 < 90%
ETCO2 (End-Tidal CO2) | 35-45 mmHg | ETCO2 outside of this range
Explain setup, operation, care, maintenance, and troubleshooting of an esophageal stethoscope, electrocardiograph, Doppler monitor, oscillometric blood pressure monitor, pulse oximeter, apnea monitor, and capnograph.
- Esophageal Stethoscope:
Setup:
Lubricate the probe and insert it into the esophagus, aiming to the right of the endotracheal tube, and advance until heart and/or respiratory noises are clearly heard.
Operation:
Listen to heart and lung sounds to assess respiratory and cardiovascular function.
Care and Maintenance:
Clean the probe with mild soapy water and dry thoroughly. Disinfect with a 70% isopropyl alcohol solution if contamination is a concern.
Troubleshooting:
If no sounds are heard, check probe placement and ensure proper connection to the stethoscope. - Electrocardiograph (ECG):
Setup:
Attach electrodes to the patient’s arms, legs, and chest, ensuring proper contact and secure placement.
Operation:
The ECG machine records the electrical signals created by the heart, displaying heart rate, rhythm, and timing of impulses.
Care and Maintenance:
Clean electrodes and cables with mild soapy water and dry thoroughly. Disinfect the machine’s external surfaces.
Troubleshooting:
If the ECG is inaccurate, check electrode placement, cable connections, and ensure the patient is lying still. - Doppler Monitor:
Setup:
Apply a Doppler probe to a peripheral artery (e.g., pedal artery) and ensure proper contact with the skin.
Operation:
The Doppler monitor uses ultrasound to detect arterial pulsations, providing information about blood flow and pulse rate.
Care and Maintenance:
Clean the probe with mild soapy water and dry thoroughly. Disinfect with a 70% isopropyl alcohol solution if contamination is a concern.
Troubleshooting:
If no signal is detected, check probe placement, ensure proper gel application, and verify the probe is functioning correctly. - Oscillometric Blood Pressure Monitor:
Setup:
Place a blood pressure cuff on a limb and ensure proper inflation and placement.
Operation:
The monitor measures blood pressure by detecting oscillations in the cuff pressure as blood flows through the artery.
Care and Maintenance:
Clean the cuff with mild soapy water and dry thoroughly. Disinfect with a 70% isopropyl alcohol solution if contamination is a concern.
Troubleshooting:
If readings are inaccurate, check cuff placement, ensure proper inflation, and verify the cuff is functioning correctly. - Pulse Oximeter:
Setup:
Attach the pulse oximeter probe to a finger, toe, or earlobe.
Operation:
The pulse oximeter measures the oxygen saturation of the blood and pulse rate.
Care and Maintenance:
Clean the probe with mild soapy water and dry thoroughly. Disinfect with a 70% isopropyl alcohol solution if contamination is a concern.
Troubleshooting:
If readings are inaccurate, check probe placement, ensure proper contact with the skin, and verify the probe is functioning correctly. - Apnea Monitor:
Setup:
Attach the apnea monitor to the patient’s chest or abdomen to detect breathing cessation.
Operation:
The monitor detects changes in chest or abdominal movement, alerting the user to potential apnea episodes.
Care and Maintenance:
Clean the monitor and probes with mild soapy water and dry thoroughly. Disinfect with a 70% isopropyl alcohol solution if contamination is a concern.
Troubleshooting:
If the monitor is not detecting breathing, check probe placement, ensure proper connection, and verify the monitor is functioning correctly. - Capnograph:
Setup: Attach the capnograph sensor to the patient’s breathing circuit or airway.
Operation: The capnograph measures end-tidal carbon dioxide (ETCO2) to assess ventilation and respiratory function.
Care and Maintenance: Clean the sensor with mild soapy water and dry thoroughly. Disinfect with a 70% isopropyl alcohol solution if contamination is a concern.
Interpret output and data from an esophageal stethoscope, electrocardiograph, Doppler monitor, oscillometric blood pressure monitor, pulse oximeter, apnea monitor, and capnograph.
- Esophageal Stethoscope:
Function:
Allows auscultation of heart and lung sounds, providing information on heart rate, rhythm, and quality of heart sounds.
Interpretation:
A change in heart sound intensity could indicate a decrease in blood pressure or cardiac output. - Electrocardiograph (ECG/EKG):
Function:
Records the electrical activity of the heart, allowing assessment of heart rate, rhythm, and identifying potential arrhythmias.
Interpretation:
Rate: Calculate the number of R-R intervals within a set time period to determine heart rate.
Rhythm: Analyze the regularity of the P-waves, QRS complexes, and T-waves to identify any irregularities.
Cardiac Axis: Assess the overall direction of the heart’s electrical activity.
P-wave, PR Interval, QRS Complex, T-wave: Evaluate the morphology and timing of these ECG waves to identify potential abnormalities. - Doppler Monitor:
Function:
Detects systolic blood pressure using the “return-to-flow” principle, relying on the Doppler effect of blood flow.
Interpretation:
Systolic Blood Pressure: The Doppler monitor displays the systolic blood pressure reading.
Accuracy: Doppler measurements are most accurate when systolic blood pressure is within normal limits and the patient has good peripheral perfusion.
Limitations: Can be affected by factors like heavy respirations, arrhythmias, hypothermia, patient motion, and electrical interference.
Describe how to determine the blood pressure using a Doppler monitor, oscillometric blood pressure monitor, or arterial catheter and transducer.
- Doppler Monitor:
Principle:
Doppler ultrasound detects blood flow in a peripheral artery, converting it into an audible sound.
Procedure:
Preparation: Clip the area over the artery (e.g., dorsal pedal artery) and apply ultrasound gel to the Doppler probe.
Placement: Position the probe over the artery and place a cuff proximally to the probe.
Inflation: Inflate the cuff until the pulse sound disappears.
Deflation: Slowly deflate the cuff until the pulse sound returns, and the cuff pressure at which the sound returns is the systolic blood pressure.
Note: Doppler monitors primarily measure systolic blood pressure. - Oscillometric Blood Pressure Monitor:
Principle:
Oscillometry detects oscillations in arterial wall diameter caused by blood pressure changes as a cuff is inflated and deflated.
Procedure:
Placement: Place the cuff on a distal artery (e.g., tail or limb).
Inflation/Deflation: The monitor automatically inflates and deflates the cuff, detecting oscillations.
Measurement: The monitor calculates and displays systolic, diastolic, and mean arterial pressures (SAP, DAP, MAP), as well as pulse rate.
Note: Oscillometric monitors provide estimates of all three blood pressure values. - Arterial Catheter and Transducer:
Principle:
An arterial catheter is inserted into an artery, and a transducer converts the pressure changes into electrical signals for continuous monitoring.
Procedure:
Catheter Placement: Insert an arterial catheter into an artery (e.g., dorsal pedal artery).
Transducer Connection: Connect the catheter to a pressure transducer.
Zeroing and Leveling: Ensure the transducer is properly zeroed and leveled to the patient’s heart level.
Continuous Monitoring: The transducer continuously monitors and displays SAP, DAP, and MAP.
Note: Arterial catheterization provides the most accurate and continuous blood pressure measurements.
Identify the following rhythms on an electrocardiographic tracing: normal sinus rhythm (NSR); sinus arrhythmia (SA); sinus bradycardia and tachycardia; first-, second-, and third-degree atrioventricular (AV) heart block; supraventricular premature complexes (SPCs) and ventricular premature complexes (VPCs); supraventricular and ventricular tachycardia; atrial and ventricular fibrillation; and QRS and T-wave configuration changes.
Identify machine-generated data that should be reported to the VIC.
Identify abnormal monitoring parameters, and list common causes of abnormal monitoring parameters.
Use monitoring parameters to determine anesthetic depth.
In veterinary anesthesia, monitoring parameters like eye position, reflexes (palpebral, corneal), muscle tone (jaw tone), response to stimulation, and respiratory/cardiovascular function are used to assess anesthetic depth, ensuring a safe and appropriate surgical plane.
Explain adverse consequences of hypothermia, and identify strategies to prevent hypothermia.
In veterinary medicine, hypothermia (low body temperature) can lead to serious complications like delayed recovery, increased risk of infection, and even death, especially during anesthesia and recovery. Prevention strategies include active warming methods and minimizing heat loss during procedures.
Adverse Consequences of Hypothermia:
Delayed Recovery:
Hypothermia can significantly prolong recovery from anesthesia, leading to increased time spent in the hospital and potential complications.
Increased Risk of Infection:
Cold temperatures can impair the immune system, making animals more susceptible to infections, including surgical site infections.
Cardiovascular Dysfunction:
Hypothermia can cause a slow, irregular heartbeat, impaired blood flow to organs, and potentially lead to cardiac arrhythmias and hypotension.
Respiratory Compromise:
Hypothermia can lead to shallow and slow breathing, potentially leading to respiratory distress or failure.
Neurological Effects:
Hypothermia can cause cerebral depression, impairing mental function and potentially leading to seizures or coma in severe cases.
Metabolic Disturbances:
Hypothermia can disrupt the body’s metabolism, leading to delayed drug metabolism, acid-base imbalances, and impaired coagulation.
Wound Healing Issues:
Hypothermia can impair wound healing, potentially leading to delayed closure and increased risk of complications
