For the EMT-Basic
Objectives Understand ALCO regulations relative to monitoring pulse oximetry by the EMT-B Review the signs and symptoms of respiratory compromise. Understand the importance of adequate tissue perfusion. Understand circumstances that hinder/prevent SpO2 readings.
ALCO Regulations Protocol pg. 47 Allows EMTs to monitor saturation of arterial oxygen levels of blood by way of pulse oximetry. Falls under Baseline vital signs
What is it used for?
Respiratory Compromise Signs and Symptoms Dyspnea Accessory muscle use Inability to speak in full sentences Adventitious breath sounds Increased or decreased breathing rates Shallow breathing Flared nostrils or pursed lips Retractions Upright or tripod position
Hypoxemia Causes lower oxygenation in arterial blood Results in decreased cellular oxygenation Anaerobic metabolism Creates energy through the combustion of carbohydrates in the absence of oxygen Loss of cellular energy production
Hypoxemia Etiology Inadequate External Respiration (in lungs) Decreased on-loading of oxygen at pulmonary capillaries Inadequate Oxygen Transport Decreased oxygen carrying capacity Inadequate Internal Respiration (in Metabolizing tissue) Decreased off-loading of oxygen at cellular capillaries
What are some causes of Hypoxemia?
Inadequate Oxygen Diffusion Pulmonary edema Fluid between alveoli and capillaries inhibit diffusion Pneumonia Reduces the surface area of respiratory membranes Reduces the ventilation-perfusion ratio COPD Air trapping in alveoli Loss of surface area of respiratory membranes
Inadequate Oxygen Transport Anemia Reduces red blood cells oxygen carrying capacity Inadequate hemoglobin results in the loss of oxygen saturation Poisoning Carbon monoxide attaches to hemoglobin more readily preventing oxygen saturation and oxygen carrying capacity Shock Low blood pressures result in inadequate oxygen carrying capacity
What should I look for?
Signs and Symptoms of Hypoxemia Restlessness/ Anxiety Altered or deteriorating mental status Increased or decreased pulse rates Increased or decrease respiratory rates Decreased oxygen oximetry readings Cyanosis (late sign)
How to Monitor Sp02
Technology The pulse oximeter has Light-emitting diodes (LEDs) that produce red and infrared light LEDs and the detector are on opposite sides of the sensor Sensor must be placed so light passes through a capillary bed Requires physiological pulsating waves to measure saturation Requires a pulse or a pulse wave (Adequate CPR)
Measuring Sp02 Oxygenated blood and deoxygenated blood absorb different light sources Oxygenated blood absorbs more infrared light Deoxygenated blood absorbs more red light Pulse oximetry reveals arterial saturation by measuring the difference.
Oxygen Saturation Definition: Percentage of hemoglobin saturated with oxygen Normal SpO2 is 94-99% Suspect perfusion compromise if less than 94% SpO2 in individuals with no known Respiratory Illness COPD Patients should have a resting SpO2 within a range of 88%-92% per county protocols.
Conditions Affecting Accuracy What to watch for: Fingernail polish and pressed on nails Dark Pigmentation of skin: Apply sensor to the fingertips of these patients (upside down). Poor circulation in elderly patients Hypothermia Possible CO poisoning Diabetes Hypotension
Interpreting Pulse Oximetry Assess and treat the PATIENT not the oximeter! Use oximetry as an adjunct to patient assessment and treatment evaluation NEVER withhold oxygen if the patient has signs or symptoms of hypoxia or hypoxemia regardless of oximetry readings!
Documentation Pulse oximetry is usually documented as SpO2 Document oximetry readings as frequently as other vital signs When oximetry reading is obtained before oxygen administration, designate the reading as room air
Summary As with all monitoring devices, the interpretation of information and response to that interpretation is the responsibility of a properly trained technician!