Monitoring for Anesthesia Flashcards
Define Monitoring?
To watch & check a situation carefully for a period of time
Why is Monitoring done in anesthesia?
Maintain normal patient physiology and homeostasis throughout the period of anaesthesia
What are the Standards for basic anaesthetic monitoring based on ?
The American Society of anaesthesiologists’ committee
What are the standards for basic anesthetic monitoring?
Standard 1 states that an anesthesia provider will be present with the patient throughout the anesthetic
Standard 2 states that the patient’s oxygenation, ventilation, circulation and temperature will be continually monitored.
According to international standards, what is the most important monitor?
The presence of the anaesthesia clinician throughout anesthesia.
What are the standard monitors used to monitor patients?(4)
1.pulse oximeter, 2.Electrocardiography
3.Noninvasive blood pressure device
6.Temperature monitor
How often should an ECG and BPs be measured?
Every 5mins
What two parameters are assessed when monitoring Oxygenation? And how are they monitored?
Inspired gas -Oxygen analyzer
Blood oxygenation-Pulse oximeter
Describe how a pulse oximeter works?
The oximeter probe consists of two parts, the light emitting diodes (LED’s) and a light detector (called a photo-detector),which emits red and infrared light. Beams of light are shone through the tissues from one side of the probe to the other. The blood and tissues absorb some of the light emitted by the probe. Oxygenated hemoglobin (HbO2) absorbs more infrared light, while deoxygenated hemoglobin (Hb) absorbs more red light. The light absorbed by the blood varies with the oxygen saturation of haemoglobin. A photodetector on the other side of the sensor measures the amount of light that passes through the tissue. The device calculates the ratio of absorbed red light to infrared light. This ratio is used to determine the percentage of hemoglobin that is saturated with oxygen (SpO2).
List factors can affect a pulse oximeter reading(6)
1.Shivering – movement may make it difficult for the probe to pick up a signal.
2.Pulse volume – the oximeter only detects pulsatile flow. When the blood pressure is low due to hypovolaemic shock or the cardiac output is low or the patient has an arrhythmia, the pulse may be very weak and the oximeter may not be able to detect a signal.
3.Vasoconstriction reduces blood flow to the peripheries. The oximeter may fail to detect a signal if the patient is very cold and peripherally vasoconstricted.
4.Carbon monoxide poisoning gives a falsely high saturation reading. Carbon monoxide binds very well to haemoglobin and displaces oxygen to form a bright red compound called carboxyhaemoglobin. This is misinterpreted by the oximeter as oxyhaemoglobin and the oximeter may read 100%, even though the true oxygen saturation is very low and the patient may be very hypoxic. This is only an issue in patients following smoke inhalation from a fire
5.Nail polish or artificial nails
6.External light-Bright light can interfere with oximeter’s sensors
What two parameters are monitored when assessing Ventilation? And what is used?
1.Qualitative clinical signs-physical exam( If breathing spontaneously check for signs of airway obstruction, listening to breath sounds, observing chest movements and symmetry and auscultating, looking at a reservoir bag)
2.Quantitative monitoring-Capnometry
What is the normal end tidal CO2 level?
35-45mmHg
What does a normal capnogram inidcate?
Intubation?
What does a sudden drop in expired CO2?
It is the first sign in pulmonary artery embolism and in air embolism.
What does a sudden increase in CO2 indicate?
It is the first warning in malignant hyperthemia
