Why has the High-Frequency Intervention Trial (HIFI) been ...

[ericka1]

Why has the High-Frequency Intervention Trial (HIFI) been criticized?
 
  A. The number of subjects used in the study was inadequate.
  B. The patient population had varied pathologies.
  C. The lack of emphasis on alveolar recruitment has been questioned.
  D. Peak and baseline pressures were not reflective of alveolar pressures.

Question 2

Which of the following terms is used to describe the phenomenon of intraunit gas mixing because of impedance difficulties?
 
  A. convective gas transport
  B. molecular diffusion
  C. coaxial flow
  D. Pendelluft

[ntsoane kedibone]

Answer to Question 1

ANS: C
A. Incorrect response: See explanation C.
B. Incorrect response: See explanation C.
C. Correct response: The National Institutes of Health High-Frequency Intervention Trial (HIFI) is the largest randomized trial of HFV ever conducted. It included 673 premature infants. HIFI showed no improvement in respiratory function or outcome, but also an increased incidence of intraventricular hemorrhage in the HFV group. The study design of the HIFI trial, however, often has been criticized for its lack of emphasis on alveolar recruitment.
D. Incorrect response: See explanation C.

Answer to Question 2

ANS: D
A. Incorrect response: See explanation D.
B. Incorrect response: See explanation D.
C. Incorrect response: See explanation D.
D. Correct response: Pendelluft is the phenomenon of intraunit gas mixing caused by impedance differences. This intraunit gas mixing also can involve airway gas and thus produce effective alveolar ventilation. Pendelluft has been particularly pronounced when HFV is used with heterogeneous impedances.