Monitoring for Radiography PPEA2 (KA)
Monitoring the Patient
Overview of monitoring vital signs and the significance of continuous observation.
Objectives
By the end of this session, you should be able to:
Understand basic principles of patient monitoring.
Record a patient’s vital signs:
Blood pressure
Pulse
Temperature
Respiratory rate
Oxygen saturation
Appreciate different oxygen delivery concentrations.
Monitoring Defined
Purpose of monitoring vital signs:
Serves as a warning system for potential issues.
Multi-parameter observations provide more data than single recordings.
Importance of Patient Observation
The foremost monitoring 'device' is the healthcare professional.
Always assess the patient visually and qualitatively.
Blood Flow Through the Heart
Cardiac output formula: Cardiac Output = Heart Rate x Stroke Volume
Major components in heart blood flow:
SVC/IVC
Pulmonary veins/arteries
Aorta
Left and Right Atriums/Ventricles
Valves (Mitral, Tricuspid, Aortic, Pulmonary)
Blood Pressure Basics
Definition: Pressure exerted by blood on vessel walls.
Components:
Systolic Pressure: Pressure during heart contraction.
Diastolic Pressure: Pressure during heart relaxation.
Factors affecting blood pressure:
Cardiac Output
Peripheral Resistance
Normal Blood Pressure Range
No universal 'normal' value; it varies between individuals.
Typical ranges:
Systolic BP: 100–140 mmHg
Diastolic BP: 60–90 mmHg
Taking Blood Pressure
Correct cuff positioning over the brachial artery is essential.
Use appropriately sized cuff.
Avoid application on:
Arms with damaged lymph drainage
Arms with an AV fistula or arterial lines.
Pulse and Its Significance
Pulse is generated by left ventricle contraction.
Pulse Pressure: Difference between systolic and diastolic BP.
Commonly palpated at these sites:
Temporal, facial, carotid, brachial, radial, femoral, popliteal, posterior tibial, dorsalis pedis arteries.
Normal Pulse Values
Adult normal range: 60 – 100 bpm.
Definitions:
Tachycardia: > 100 bpm.
Bradycardia: < 60 bpm.
Physiological variations exist depending on age and fitness level.
Taking a Pulse
Locate pulse using index and middle fingers (avoid thumb).
Compress artery lightly yet firmly.
Count beats for a full minute.
Record:
Rate
Rhythm (regular/irregular)
Volume (strength)
Respiratory Rate Measurement
Determine presence of breathing by:
Observation (look, listen, feel).
Count breaths within one minute.
Assessment factors:
Regularity
Depth (shallow/deep)
Noisiness
Equal movement of the chest.
Describing Respiratory Symptoms
Common terms:
Dyspnoea: Difficulty in breathing.
Apnoea: Temporary cessation of breathing.
Orthopnea: Breathing difficulty when lying flat.
Tachypnea: Rapid breathing.
Wheezing: High-pitched sound during breathing due to narrowing airways.
Cyanosis: Bluish discoloration due to low oxygen.
Hypoxia: Low oxygen levels in tissues.
Normal Respiration Rates
Adults: 12-18 breaths/minute.
Specific rates for children:
8-year-olds: 20 breaths/minute.
1-year-olds: 30 breaths/minute.
Neonates: 40 breaths/minute.
Pulse Oximetry
Non-invasive method to monitor oxygen saturation in blood (SaO2%).
Main function: Detect hypoxaemia.
Benefits of Pulse Oximetry
Evaluates patient's oxygen status.
Detects low oxygen saturation before visible blue/gray cyanosis occurs.
Haemoglobin (Oxygen) Saturation
Haemoglobin's affinity for oxygen allows rapid binding.
Normal arterial saturation roughly: 97% with healthy individuals breathing 21% oxygen (atmospheric air).
Venous blood saturation should be about 75%.
Sources of Error in Oximetry
Influencing factors include:
Ambient light
Movement
Cold temperatures
Reduced blood flow
Regularity of pulse
Further errors can stem from:
Carbon monoxide poisoning
Contrast dyes
Nail polish.
Patient Care Considerations
Risks include:
Pressure damage from prolonged use.
Burns from prolonged heat of light source.
Cross infection risk.
Practical Tips for Oximetry
Allow several seconds for device stabilization after probe application.
Ensure waveform detection for accuracy.
Recognize that physiological changes in saturation are not instantaneous.
Temperature Monitoring
Normal core temperature typically maintained around 37±1°C.
Core temperature is generally higher than skin temperature.
Factors influencing core temperature:
Metabolic rate.
Methods of Measuring Temperature
Can include rectal, oesophageal, or pharyngeal probes.
Recommendations include waiting after:
Vigorous exercise or hot baths (1 hour).
Smoking, eating, or drinking hot/cold liquids (20-30 minutes).
Temperature Definitions
Hypothermia: Core temperature below 36°C (treatment needed below 35°C; life-threatening below 32°C).
Hyperthermia: Abnormally high body temperature (less common than hypothermia), often due to:
Infectious fever
Drug reactions
Thyroid crisis.
Oxygen Therapy Overview
Administration of oxygen greater than room air levels.
Indicates prevention or treatment for hypoxaemia.
Essential for maintaining proper oxygen saturation levels.
Oxygen Delivery Methods
Face Mask:
Advantages: Controlled concentration delivery (e.g., Venturi).
Disadvantages: Patients may remove it to eat/talk; potential claustrophobic feelings.
Nasal Cannula:
Advantages: Allows eating/talking; continuous delivery.
Disadvantages: Not suitable for acute respiratory failure; variable concentration delivery.
Advanced Oxygen Therapy Considerations
Unconscious patients requiring oxygen may need an endotracheal tube.
Oxygen administration could be via ventilators or spontaneous breathing techniques.
References
Nicol, M. et al. (2008). Observation and monitoring: Essential Nursing Skills (3rd Edition). Edinburgh: Mosby.
Ehrlich, R.A., Coakes, D.M. (2017). Patient Care in Radiography (9th Edition). Missouri: Elsevier.