Detailed Instructions: Given an abstract, generate a keyword (a noun phrase) that best describes the focus or contribution of the paper. Such keywords can be directly from the given abstract or outside it.
See one example below:
Problem: Abstract: Some patients converted from ventricular fibrillation to organized rhythms by defibrillation - trained ambulance technicians(EMT - Ds) will refibrillate before hospital arrival.The authors analyzed 271 cases of ventricular fibrillation managed by EMT - Ds working without paramedic back - up.Of 111 patients initially converted to organized rhythms, 19(17 % ) refibrillated, 11(58 % ) of whom were reconverted to perfusing rhythms, including nine of 11(82 % ) who had spontaneous pulses prior to refibrillation.Among patients initially converted to organized rhythms, hospital admission rates were lower for patients who refibrillated than for patients who did not(53 % versus 76 % , P = NS), although discharge rates were virtually identical(37 % and 35 % , respectively).Scene - to - hospital transport times were not predictively associated with either the frequency of refibrillation or patient outcome.Defibrillation - trained EMTs can effectively manage refibrillation with additional shocks and are not at a significant disadvantage when paramedic back - up is not available.
Solution: Ventricular Fibrillation
Explanation: This term is directly present in the abstract and it is one of the main topic in it. So can be chosen as the medical subject heading.

Problem: Abstract: To study the metabolic acidosis that occurs during the diarrhea of cholera, we examined the serum anion gap in 21 patients with hypovolemic shock due to Vibrio cholerae infection. Measurements of serum electrolytes, as well as divalent cations and the anionic contributions of serum proteins, lactate, phosphate, and serum creatinine, were made at the time of admission, after rehydration, and during convalescence. At the time of admission, the mean serum concentration of sodium was 134.8 mmol (meq) per liter, that of chloride was 103.2 mmol per liter, and that of bicarbonate was 11.4 mmol per liter; the mean anion gap was 20.2 mmol per liter. The mean serum creatinine concentration was 2.48 mg per deciliter. The low serum bicarbonate level and the high serum anion gap were corrected by rehydration. The increased serum anion gap was caused by hyperproteinemia, lactic acidemia, and hyperphosphatemia, with anionic contributions to the rise in anion gap estimated as protein, 5.5 meq per liter; lactate, 2.5 meq per liter; and phosphate, 2.5 meq per liter. The hyperproteinemia was attributed to dehydration, the lactic acidemia to shock, and the hyperphosphatemia to acidosis and transient renal failure. The mean concentrations of serum calcium and magnesium were slightly elevated but did not affect the increased anion gap. These results indicate that severe cholera causes acidosis with relatively little change in serum chloride but an increased serum anion gap. The acidosis is more profound than would be expected on the basis of stool losses of bicarbonate, because of superimposed lactic acidemia and renal failure.
Solution:
Acid-Base Equilibrium