Power is the probability that a study will reject the null hypothesis. difference between the null and alternative hypotheses. level of significance, and the null vs. alternative difference. a numeric example of power and sample size estimation for the one-sample case.
During the procedure the patient is unconscious and unaware of the need to urinate. After the procedure, however, it may not be safe for the patient to walk. They may be too sick to take care of their own bathroom needs or their surgeon may feel that a catheter is best for their particular recovery.
If the patient has a catheter-associated UTI, the old catheter should be removed and the specimen should be collected using sterile technique when the new catheter is placed. Bacterial colonization of the urethra and the bladder is inevitable. Routine irrigation of long-term catheters is not indicated.