Final answer:
The nurse should interrupt the therapy due to the significant rise in heart rate to 140 bpm, which is indicative of tachycardia and could signal a potential adverse reaction requiring immediate attention.
Step-by-step explanation:
When a client reports fatigue and shows a significant increase in heart rate from 90 to 140 beats per minute during chest physiotherapy (CPT), the nurse's priority should be to assess the patient's overall condition immediately. Considering the physiological impact and symptoms associated with tachycardia, which includes dizziness, shortness of breath, and chest pain, it is essential for the nurse to take immediate action. In this scenario, interrupting the therapy would be the most prudent step to address the potential adverse reaction and prevent complications such as syncope or cardiac arrest that could necessitate cardiopulmonary resuscitation (CPR).
The abnormal rise in heart rate during a resting state such as CPT can signal an underlying condition or excessive stress on the cardiovascular system. Notably, a resting heart rate above 100 bpm is considered tachycardia and in this situation, where the rate is 140 bpm, patient safety becomes the immediate concern.