OXYGEN DEVICES
A mask that should never be run below 5 L/min due to the retention of CO₂.
Simple Mask
This is the first setting one would change when their patient has an elevated PaCO2 on BiPAP.
IPAP
A breath sound that may temporarily clear after coughing, suggesting airway secretions.
Rhonchi
A sign of a paradoxical reaction to bronchodilator therapy.
Bronchospasm
A type of hypoxia that does not improve with supplemental oxygen.
Histotoxic hypoxia
A device chosen when a patient needs a precise and stable FiO₂ regardless of breathing pattern.
Venturi/AEM
An acid-base state shown by: pH 7.32, PaCO₂ 55, HCO₃ 29.
Partially compensated respiratory acidosis.
A condition suggested by hyperresonance with absent breath sounds on one side.
Pneumothorax
The reason an MDI delivers poorly when a patient inhales too quickly.
Upper airway impaction
Two physiological mechanisms by which postoperative patients develop atelectasis.
Low tidal volumes and mucus retention
Two reasons a nonrebreather reservoir bag may collapse even when the flow is set at 12 L/min.
Poor mask seal or higher inspiratory demand
A clinical situation where PaO₂ is severely low while PaCO₂ remains normal.
A shunt.
Two possible causes of late inspiratory crackles in the lung bases.
Pulmonary edema and atelectasis
Three situations where heated aerosol should be avoided.
Airway burns, bleeding, swelling/bronchospasm risk
A reason a patient may have normal SpO₂ but still be hypoxic in an anemic state.
Decreased Hgb
A nasal cannula flow that most closely approximates 35% oxygen — but provides imprecise FiO₂.
4-6LPM
The reason pH 7.44, PaCO₂ 30, HCO₃ 20 represents compensation rather than a primary disorder.
Respiratory compensation for metabolic acidosis.
A radiographic difference: one shows air bronchograms without volume loss, and the other shows volume loss with tracheal shift.
Consolidation and atelectasis.
A correct decision when HR increases by 18 bpm during SVN, SpO₂ improves, but tremors worsen.
Continue the treatment and monitor closely
A patient performing repeated IS inhalations becomes dizzy and develops perioral tingling due to excessive CO₂ washout.
Hyperventilation
Two physiologic concepts you must consider before increasing oxygen in a lethargic COPD patient on 2 L NC.
Worsening V/Q mismatch and potential hypoventilation from increased FiO₂
Values showing combined respiratory and metabolic alkalosis.
A high pH with both low PaCO₂ and high HCO₃
A pattern (accessory muscle use, paradoxical breathing, distant breath sounds) that indicates this kind of problem.
A ventilation problem.
The reason a DPI may not work well in an acute asthma exacerbation.
Inadequate inspiratory flow
A gas-exchange pattern characterized by poor response to 100% oxygen, consolidation, and low SpO₂.
A shunt.