Chapter 17: Emergency Procedures

NORMAL VALUES FOR VITAL SIGNS

Two standard tables (average and normal limits) are shown for comparison.

PULSE OXIMETRY

The pulse oximeter measures oxygen saturation of arterial blood (SpO₂).

Facts and figures

In a healthy young person the O₂ saturation should be 95–99%. It varies with age, the degree of fitness, current altitude and oxygen therapy. Studies show that Caucasian race, obesity and male sex but not smoking are associated with lower SpO₂ readings.¹

The ideal value is 97–100%.

The median value in neonates is 97%, in young children 98% and adults 98%.

Target oxygen saturation

• Asthma—the aim is to maintain SpO₂ > 94%

• Acute coronary syndromes ≥ 94%

• Opioid effect ≥ 94%

• Type 1 (hypoxemic) respiratory failure (e.g. interstitial lung disease, pneumonia, pulmonary oedema) ≥ 94%

• Severe COPD with hypercapnoeic respiratory failure 88–92%

• Critical illness (e.g. major trauma, shock) 94–98%

• Children > 94% (< 94% is a concern)

Indications for oxygen therapy to be beneficial

• Australian guideline to improve quality of life > 88%

• UK: adults < 50 years 90%, asthma 92.3%

Availability and cost

Pulse oximeters are readily available from medical and surgical suppliers with a range in cost from about $30 to $2000. A good-quality unit is available for about $200 to $400.

ACUTE CORONARY SYNDROMES

In the author’s rural practice, over a period of 10 years, the most common cause of sudden death was myocardial infarction, which was responsible for 67% of deaths in the emergency situation. The importance of confirming early diagnosis with the use of the electrocardiogram (ECG) and serum markers, especially troponin, is obvious. A summary of acute coronary syndromes is presented in Table 17.3.