Influence of different methods of synchronized mechanical ventilation on ventilation, gas exchange, patient effort, and blood pressure fluctuations in premature neonates
✍ Scribed by Helmut Hummler; Tilo Gerhardt; Alvaro Gonzalez; Nelson Claure; Ruth Everett; Eduardo Bancalari
- Publisher
- John Wiley and Sons
- Year
- 1996
- Tongue
- English
- Weight
- 767 KB
- Volume
- 22
- Category
- Article
- ISSN
- 8755-6863
No coin nor oath required. For personal study only.
✦ Synopsis
Westudiedtheeffectsoftwo methodsof synchronized mechanicalventilation [synchronized intermittent mandatory ventilation (SIMV) and assistlcontrol (NC)] on ventilation, gas exchange, patient effort, and arterial blood pressure (ABP) fluctuations. SIMV and N C were applied in random order in 12 preterm neonates (gestational age, 29.7 t 2.3 weeks; birth weight, 1,217 5 402 9). We measured total (Vela,) and mechanical (Vemech) minuteventilation, spontaneous (Vtswnl) and ventilator supported (Vtmwh) tidal volume, transcutaneous oxygen saturation (Spo2), transcutaneous Po, (TcP,), and Pco,, (TcPco,), mean airway pressure (PG), phasic esophageal pressure deflections (Pe) as an estimate of inspiratory effort, mean arterial blood pressure (ABP), and beat-to-beat ABP fluctuations. The measurements obtained during conventional intermittent mandatory ventilation (IMV) were compared with the recordings during SlMV and NC. To make the measurement conditions comparable and to prevent hyperventilation, peak inspiratory pressure was reduced during the NC mode so that Vel a, remained in the same range as during the IMV mode. Whereas Ve, was similar in all three conditions by study design, Vemech was larger during SlMV and NC than during IMV. Vtmsch increased during SlMV and by study design was smaller during MC than during IMV. Pe decreased during SlMV and AJC compared with IMV, and Paw was higher during A/C than during IMV or SIMV. Beat-to-beat ABP fluctuations were reduced during SlMV and NC compared with IMV and showed a close positive correlation with Pe changes. We conclude that SlMV increases Vemech and reduces Pe compared with IMV, resulting in smaller intrathoracic and ABP fluctuations. During NC, a substantial portion of the spontaneous respiratory effort is shifted to the ventilator, resulting in a further decrease in Pe and ABP fluctuations.