In analyzing the ECG strip, the nurse notices a spike before each ...

[ss2343]

In analyzing the ECG strip, the nurse notices a spike before each QRS complex. The patient's heart rate is 70 beats/min. This phenomenon is reflective of
 
  a. 60-cycle electrical interference; check equipment.
  b. pacing artifact; the pacemaker is sensing and capturing.
  c. electrical artifact; the pacemaker is not sensing.
  d. patient movement; check electrodes.

Question 2

Use of oxygen therapy in the patient who is hypercapnic may result in
 
  a. oxygen toxicity.
  b. absorption atelectasis.
  c. carbon dioxide retention.
  d. pneumothorax.

[fdliggud]

Answer to Question 1

B
The pacing artifact is the spike that is seen on the electrocardiographi c tracing as the pacing stimulus is delivered to the heart. A P wave is visible after the pacing artifact if the atrium is being paced. Similarly, a QRS complex follows a ventricular pacing artifact. With dual-chamber pacing, a pacing artifact precedes both the P wave and the QRS complex.

Answer to Question 2

C
Deoxygenated hemoglobin carries more CO2 compared with oxygenated hemoglobin. Administration of oxygen increases the proportion of oxygenated hemoglobin, which causes increased release of CO2 at the lung level. Because of the risk of CO2 accumulation, all patients who are chronically hypercapnic require careful low-flow oxygen administration.