High-frequency oscillatory ventilation: "Please do not forget me," said the stethoscope

A new method for continuous monitoring of chest wall movement to characterize hypoxemic episodes during HFOV

INTRODUCTION

Monitoring ventilated infants is difficult during high-frequency oscillatory ventilation (HFOV). This study tested the possible causes of hypoxemic episodes using a new method for monitoring chest wall movement during HFOV in newborn infants.

METHODS

Three miniature motion sensors were attached to both sides of the chest and to the epigastrium to measure the local tidal displacement (TDi) at each site. A >20% change in TDi was defined as deviation from baseline.

RESULTS

Eight premature infants (postmenstrual age 30.6 ± 2.6 weeks) were monitored during 10 sessions (32.6 h) that included 21 hypoxemic events. Three types of such events were recognized: decrease in TDi that preceded hypoxemia (n = 11), simultaneous decrease in TDi and SpO2 (n = 6), and decrease in SpO(2) without changes in TDi (n = 4). In the first group, decreases in TDi were detected 22.4 ± 18.7 min before hypoxemia, and were due to airway obstruction by secretions or decline in lung compliance. The second group resulted from apnea or severe abdominal contractions. In the third group, hypoxia appeared following a decrease in FiO2.

CONCLUSIONS

Monitoring TDi may enable early recognition of deteriorating ventilation during HFOV that eventually leads to hypoxemia. In about half of cases, hypoxemia is not due to slowly deteriorating ventilation.

Nursing and infection-control issues during high-frequency oscillatory ventilation

OBJECTIVES

To review the specific nursing and infection-control issues that arise during the care of patients receiving high-frequency oscillatory ventilation (HFOV).

DATA SOURCE

Published articles, governmental guidelines, and hospital procedures and practices.

DATA SUMMARY

Nurses, respiratory therapists, and other clinicians caring for patients receiving HFOV need to be aware of specific differences in patient assessment, including close observation for symmetric chest-wall vibrations. In addition, management of sedation with or without neuromuscular blockade and effective communication with the patients are essential nursing skills needed with the use of HFOV. From an infection-control standpoint, HFOV is considered a high-risk respiratory procedure because of the inability to effectively filter all respiratory secretions. Appropriate infection-control precautions, including patient location and use of personal protective equipment, need to be considered when implementing HFOV in the intensive care unit.

CONCLUSIONS

Important infection-control and nursing issues exist that are specific to the use of HFOV. These issues should be addressed with appropriate staff education before the implementation of HFOV in an intensive care unit.