Respiratory Therapy Basics

01Normal SpO2 & When Oxygen Is Indicated

A normal SpO2 for a healthy adult on room air is roughly 94-100%. Supplemental oxygen is generally indicated when SpO2 drops to about 92% or below (with a lower target of 88-92% specifically for patients who chronically retain CO2, such as some with severe COPD), aiming to correct hypoxemia rather than push saturation higher than necessary.

02O2 Delivery Devices — Nasal Cannula vs. Non-Rebreather

A nasal cannula is a low-flow device typically run at 1-6 L/min, delivering roughly 24-44% FiO2, used for patients with mild-to-moderate hypoxemia who are breathing adequately. A non-rebreather mask is used for more severe hypoxemia, run at 10-15 L/min (high enough to keep the reservoir bag from collapsing), delivering up to roughly 60-90%+ FiO2.

03COPD & Oxygen Caution

In patients with severe COPD, giving too much supplemental oxygen can worsen CO2 retention (hypercapnia) — modern evidence attributes this mainly to changes in ventilation/perfusion matching rather than the older 'hypoxic drive' theory alone. The practical guideline: titrate oxygen in COPD patients to a target SpO2 around 88-92% rather than driving saturation to normal-range levels.

04ABG Basics

A normal arterial blood gas has pH 7.35-7.45, PaCO2 35-45 mmHg, and HCO3 22-26 mEq/L. Assess pH first to identify acidosis or alkalosis, then check whether PaCO2 (respiratory) or HCO3 (metabolic) is driving the change, and whether the other value shows compensation.

05Nebulizer vs. MDI with Spacer

A nebulizer turns liquid medication into a fine mist inhaled over several minutes and requires little patient coordination — useful for very young, elderly, or acutely distressed patients. An MDI (metered-dose inhaler) delivers medication in a single puff and, paired with a spacer, works just as well for most patients; the spacer reduces the coordination required and improves how much medication reaches the lungs versus the mouth and throat.

06Incentive Spirometry

An incentive spirometer encourages slow, deep breaths using visual feedback (a rising piston or ball) to help re-expand the lungs and mobilize secretions, reducing the risk of atelectasis, pneumonia, and other complications after surgery or during prolonged bed rest.