A patient 90 years old, suffering congestion, dry cough, urinary infection, under dosage of cough syrup was sleepy. Then was given Cefuroxime, Linezolid antibiotic, corex syp and metolazone diuretics when partially conscious. He didnt eat much drank 50 ml water in last 14 hours and nothing after that. Later in the evening his oxygen was down to 70 SpO2. In 1.5 hours he was given oxygen with oxygen machine and the oxygen started to increase in a bit. In an hour heartrate started to fluctuate BP was almost NR. The patient suffered cardiac arrest few minutes later. The patient wasn't a major heart patient. He was taken off ecosprin a few days ago suffering heavy bleeding through stool which was diagnosed due to piles.
Q1. What could have caused the cardiac arrest? Severe dehydration, Electrolyte Imbalance?
Q2. What steps at the time of cardiac arrest in the above situation could have saved the patient except for CPR?