Assessment of Airways Mechanical Properties by Forced Oscillatory Technique (FOT) and Laser Interferometry (LIR) During Anesthesia.
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 入组人数
- 14
- 试验地点
- 1
- 主要终点
- Change in respiratory system impedance
研究概览
简要总结
The aims of the present study are:
- To evaluate the effect of the induction of anaesthesia and paralysis in terms of changes in oscillatory mechanics parameters
- To evaluate the mechanical properties of the respiratory system in terms of input and transfer oscillatory impedance in response to PEEP changes
详细描述
It has been recently shown that respiratory system reactance (Xrs) obtained by the forced oscillation technique (FOT) at 5 Hz is more reliable than dynamic compliance for assessing lung collapse and the effects of lung RMs in a porcine ALI model ( Ref.1,2).
Specifically, Xrs (and its derived variable CX5, the oscillatory compliance at 5 Hz) identifies the minimum positive end-expiratory pressure (PEEP) level required to maintain lung recruitment with high sensitivity and specificity. Moreover, it has been recently demonstrated that Xrs may be used to identify the lowest level of PEEP able to prevent atelectasis and that PEEP setting strategy based on maximizing Xrs is able to limit lung injury compared to oxygenation-based approach in a porcine lavage model of lung injury. ( Ref.3)
Recently, at the biomedical engineering department of Politecnico di Milano measurements of chest wall displacement have been successfully performed by means of an optical sensor realized using a laser self-mixing interferometer (LIR). The advantage of this approach is that it is contact-less, that by deflecting the laser been it is possible to scan any region of the chest wall surface and that it allows to measure also low-frequency vibrations.
Protocol
- The baseline pulmonary function will be assessed by spirometry before surgery.
- Just before surgery measurements of oscillatory mechanics will be performed at the following stages:
研究设计
- 研究类型
- Observational
- 时间视角
- Prospective
入排标准
- 年龄范围
- 18 Years 至 80 Years（Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 否
入选标准
- •age >18 years
- •ASA I-II, scheduled for elective surgery requiring general anesthesia
- •signed informed consent
排除标准
- •patient refusal
- •BMI > 35
- •co-existing respiratory disease (COPD, asthma, restrictive lung disease)
- •pregnancy
结局指标
主要结局
Change in respiratory system impedance
时间窗: baseline and 5 minutes of ventilation
FOT measurements: Respiratory system impedance will be computed from the flow and pressure signals measured at the inlet of the tracheal tube. A composite waveform including 5, 11 and 19 Hz will be used as a stimulating signal generated by an A/D-D/A board and amplified by a power amplifier that drives a loudspeaker the output of which is connected to inspiratory line of the ventilator.
次要结局
- Change in chest wall displacement measured by LIR(baseline and 5 minutes of ventilation)
- Change in oxygenation (paO2)(baseline and 5 minutes of ventilation)
- Change in Functional residual capacity (FRC)(baseline and 5 minutes of ventilation)
研究者
Peter Kostic
Principal investigator
Uppsala University Hospital