A key definition is that any symptom occurring during a reflux episode or within 2 minutes of its ending is considered reflux-related.
Patient testing: esophageal pH monitoring
Parameters:
(1) number of minutes recorded
(2) number of minutes pH < 4
(3) number of reflux episodes
(4) number of reflux-related symptoms
(5) total number of symptoms during monitoring
p =
= ((total number of minutes pH < 4) + (2 * (number of reflux episodes))) / (total number of minutes recorded)
The binomial distribution was used to determine the probability of the symptoms being a chance occurrence. If the probability is < 0.05 then it is not considered a chance occurrence.
probability of "x" symptoms occurring with acidity by chance =
= FACTORIAL(total number of symptoms) / (FACTORIAL(x) * FACTORIAL((total number) - (x))) * (p^(x)) * ((1 - (p))^((total number) - (x)))
probability of "x" or more symptoms occurring with acidity by chance =
= (probability of "x") + (probability of "x+1") + …. + (probability of (total number of symptoms))
where:
• In Appendix B the data uses the results for "x" or more symptoms. However, since only "x" reflux symptoms occurred I am not sure why the probabilities for additional symptoms are included.
