Medical Exam 2 - Hypoxemia & Hypoxia

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Questions and Answers

What is the primary measure of oxygen saturation in the blood known as SpO2?

The pressure of O2 within the alveoli as measured by arterial blood gas.

The amount of hemoglobin saturated with O2 as measured by pulse oximetry. (correct)

The volume of air exchanged in the lungs over a minute.

The concentration of O2 in the inspired air.

Which statement about low flow and high flow devices is true?

High flow devices are only suitable for treating severe hypoxemia.

Only high flow devices require the patient to wear a face mask.

High flow devices can generally meet the flow demand of a patient. (correct)

Low flow devices can be used for all levels of oxygen deficiency.

When hearing a high-pitched sound from a patient on a 5L nasal cannula, what action should be prioritized?

Increase the flow rate to ensure adequate oxygen delivery.

Immediately replace the nasal cannula with a different device.

Replace the bubble humidifier. (correct)

Assess the patient's overall breathing pattern.

In the use of an air entrainment device set at 65% oxygen at 15 lpm, what is the expected total flow rate?

35 L/min Signup and view all the answers

Which statement about the application of an oxygen hood for an infant is NOT correct?

Temperature regulation is unnecessary once the hood is applied. Signup and view all the answers

How would you classify a patient with a PaO2 of 48 torr?

Mild hypoxemia Signup and view all the answers

What is the initial treatment for a fireman with carbon monoxide levels at 35%?

Place on a 15L non-rebreather mask Signup and view all the answers

What causes absorption atelectasis?

Excessive oxygen replacing nitrogen in the alveoli Signup and view all the answers

Which statement is NOT true regarding oxygen therapy?

There is no limit to the amount of oxygen if CO2 remains normal. Signup and view all the answers

Which statements about the oxyhemoglobin dissociation curve are correct?

It shows how blood carries and releases oxygen under various conditions. Signup and view all the answers

Which mixtures of helium to oxygen are most commonly used in Heliox therapy?

80:20 and 70:30 Signup and view all the answers

Which statement correctly distinguishes between hypoxemia and hypoxia?

Hypoxemia can be a cause of hypoxia. Signup and view all the answers

Which clinical sign is least indicative of the need for oxygen therapy?

Decreased heart rate Signup and view all the answers

What is an inappropriate indication for administering oxygen therapy?

A patient with mild respiratory distress and normal PaO2 levels. Signup and view all the answers

When managing a patient with COPD who has a saturation goal of 88%, what is the most appropriate initial response when the medication order is unclear?

Call the doctor for clarification Signup and view all the answers

What is the most appropriate next step for a patient with weak and shallow breathing after a slight improvement in SpO2?

Draw an arterial blood gas (ABG) to assess ventilation status. Signup and view all the answers

If a patient on 90% FiO2 is still experiencing low SpO2 levels, what would be the most appropriate intervention?

Suggest placing the patient on CPAP therapy Signup and view all the answers

Which of the following statements about ventilation and oxygenation is TRUE?

Oxygenation can occur independent of proper ventilation. Signup and view all the answers

In evaluating a patient with an SpO2 of 82% on a 2L nasal cannula with a PaO2 of 110 mmHg, what is the best course of action?

No changes are necessary - the patient is fine Signup and view all the answers

Given a SpO2 reading of 93% and a PaO2 of 42 mmHg, what should be the next step for the patient?

Draw blood to check for anemia. Signup and view all the answers

When considering signs of hypoxemia, which of the following symptoms might you prioritize for assessment?

Tachycardia and shallow breathing. Signup and view all the answers

What should be done if a non-rebreather mask bag is completely collapsing during inspiration?

Increase the flow to 15 L/min. Signup and view all the answers

What is the expected outcome of placing a patient with SpO2 at 78% on a non-rebreather mask?

Significant increase in SpO2 within a few minutes. Signup and view all the answers

If a patient on a 6 L nasal cannula remains at 88% SpO2 after increasing flow from 6 L/min to 8 L/min, what is the most likely explanation?

The patient may be experiencing an exacerbation of COPD. Signup and view all the answers

In the context of hypoxia, which physiological change might NOT be expected as a direct consequence?

Decreased blood pressure as a result of inadequate perfusion. Signup and view all the answers

For a patient on an aerosol mask requiring 50% oxygen, why is an input flow of 10 L/min insufficient?

The flow rate must exceed 30 L/min to meet inspiratory demand. Signup and view all the answers

What is the primary cause of a malfunctioning oxygen analyzer?

The membrane is torn. Signup and view all the answers

When the oxygen analyzer reads 25% after dialling in an FiO2 of 40% on an oxygen blender, what corrective action should be taken?

Calibrate the oxygen analyzer. Signup and view all the answers

Study Notes

Hypoxemia and Hypoxia

Hypoxemia refers to below-normal oxygen content in arterial blood.
Hypoxia indicates insufficient oxygen reaching tissues.
Hypoxemia can lead to hypoxia, but it may not be a direct cause.

Oxygen Therapy Indications

Oxygen therapy is indicated for suspected hypoxia and low PaO2 levels.
Patients with lung injuries, like those from motor vehicle accidents, may not be suitable for immediate oxygen therapy without assessment.

Patient Monitoring and Interventions

For patients with severe hypoxia (SpO2 78%): Place on non-rebreather mask; if improvement is minimal, consider drawing arterial blood gas (ABG) to assess ventilation status.
Ventilation and oxygenation are different concepts; proper cardiac output is essential for oxygenation.

ABG Findings and Actions

A PaO2 of 42 mmHg indicates a severe hypoxemic condition.
In suspected cases of carbon monoxide poisoning, high CO levels require immediate administration of oxygen through a non-rebreather mask and hyperbaric treatment.

Atelectasis

Absorption atelectasis occurs when alveoli collapse due to excess oxygen displacing nitrogen.

Oxygen Therapy Rules

Oxygen administration is generally limited despite normal carbon dioxide levels to prevent toxicity.

Oxyhemoglobin Dissociation Curve

This curve illustrates the relationship between hemoglobin saturation and oxygen tension.
Increased CO2 and lower pH shift the curve to the right, implying reduced oxygen affinity.

Pulse Oximetry Relationship

SpO2 measures hemoglobin oxygen saturation via pulse oximetry, while SaO2 does so through arterial blood gas analysis.
PaO2 indicates the pressure exerted by oxygen in the alveoli for effective gas exchange.

Low Flow vs. High Flow Devices

Low-flow devices suit mild to moderate hypoxemia; high-flow devices can meet a patient’s entire flow demand.
Cyanotic patients typically require high-flow devices.

Troubleshooting Oxygen Devices

High-pitched sounds with nasal cannulas may indicate issues with the bubble humidifier or flow connections.
Ensure proper flow rates with specific devices to meet oxygen demands effectively.

Oxygen Analyzer Issues

Malfunctions could stem from torn membranes or improper calibration, potentially misrepresenting oxygen concentrations.

Heliox Therapy

Common mixtures include 80:20 and 70:30 helium to oxygen for specific therapeutic purposes.

Clinical Protocols and Clarifications

Always confirm unclear physician orders related to oxygen saturation targets in patients with COPD.
Explore alternatives (like CPAP) for patients not achieving desired SpO2 levels.

Final Recommendations

ABG results showing high PaO2 may not necessitate changes in oxygen therapy if the patient remains stable.

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Description

Prepare for your Medical Exam 2 with these review questions focusing on hypoxemia and hypoxia. Test your understanding of oxygen levels in the blood and their implications for tissue oxygenation. This quiz will help reinforce key concepts critical for your studies.