患者触发通气对心脏手术后婴儿呼吸负荷的影响。

Effect of patient-triggered ventilation on respiratory workload in infants after cardiac surgery.

作者信息

Takeuchi M, Imanaka H, Miyano H, Kumon K, Nishimura M

机构信息

Surgical Intensive Care Unit, National Cardiovascular Center and Intensive Care Unit, Osaka University Hospital, Osaka, Japan.

出版信息

Anesthesiology. 2000 Nov;93(5):1238-44; discussion 5A. doi: 10.1097/00000542-200011000-00017.

DOI:10.1097/00000542-200011000-00017

PMID:11046212

Abstract

BACKGROUND

Patient-triggered ventilation (PTV) is commonly used in adults to avoid dyssynchrony between patient and ventilator. However, few investigations have examined the effects of PTV in infants. Our objective was to determine if pressure-control PTV reduces infants' respiratory workloads in proportion to the level of pressure control. We also explored which level of pressure control provided respiratory workloads similar to those after the extubation of the trachea.

METHODS

When seven post-cardiac surgery infants, aged 1 to 11 months, were to be weaned with the pressure-control PTV, we randomly applied five levels of pressure control: 0, 4, 8, 12, and 16 cm H2O. All patients were ventilated with assist-control mode, triggering sensitivity of 1 l/min, and positive end-expiratory pressure of 3 cm H2O. After establishing steady state conditions at each level of pressure control, arterial blood gases were analyzed and esophageal pressure (Pes), airway pressure, and airflow were measured. Inspiratory work of breathing (WOB) was calculated using a Campbell diagram. A modified pressure-time product (PTPmod) and the negative deflection of Pes were calculated from the Pes tracing below the baseline. The measurement was repeated after extubation.

RESULTS

Pressure-control PTV supported every spontaneous breath. By decreasing the level of pressure control, respiratory rate increased, tidal volume decreased, and as a result, minute ventilation and arterial carbon dioxide partial pressure were maintained stable. The WOB, PTPmod, and negative deflection of Pes increased as pressure control level was decreased. The WOB and PTPmod at 4 cm H2O pressure control and 0 cm H2O pressure control and after extubation were significantly greater than those at the pressure control of 16, 12, and 8 cm H2O (P < 0.05). The WOB and PTPmod were almost equivalent after extubation and at 4 cm H2O pressure control.

CONCLUSIONS

Work of breathing and PTPmod were changed according to the pressure control level in post-cardiac surgery infants. PTV may be feasible in infants as well as in adults.

摘要

背景

患者触发通气（PTV）常用于成人以避免患者与呼吸机不同步。然而，很少有研究探讨PTV对婴儿的影响。我们的目的是确定压力控制型PTV是否能按压力控制水平成比例地降低婴儿的呼吸负荷。我们还探讨了哪种压力控制水平能提供与气管拔管后相似的呼吸负荷。

方法

当7名年龄在1至11个月的心脏手术后婴儿采用压力控制型PTV进行撤机时，我们随机应用了5个压力控制水平：0、4、8、12和16cmH₂O。所有患者均采用辅助控制模式通气，触发敏感度为1L/min，呼气末正压为3cmH₂O。在每个压力控制水平建立稳态条件后，分析动脉血气并测量食管压力（Pes）、气道压力和气流。使用坎贝尔图计算吸气呼吸功（WOB）。根据基线以下的Pes描记图计算改良压力-时间乘积（PTPmod）和Pes的负向偏移。气管拔管后重复测量。

结果

压力控制型PTV支持每一次自主呼吸。通过降低压力控制水平，呼吸频率增加，潮气量减少，结果分钟通气量和动脉二氧化碳分压保持稳定。随着压力控制水平降低，WOB、PTPmod和Pes的负向偏移增加。4cmH₂O压力控制、0cmH₂O压力控制时以及气管拔管后的WOB和PTPmod显著大于16、12和8cmH₂O压力控制时（P<0.05）。气管拔管后和4cmH₂O压力控制时的WOB和PTPmod几乎相等。