Smith Anne-Louise, Owen Harry, Reynolds Karen J
The Medical Device Research Institute, Flinders University, GPO Box 2100, Adelaide, SA, 5001, Australia,
J Clin Monit Comput. 2015 Jun;29(3):393-405. doi: 10.1007/s10877-014-9617-z. Epub 2014 Sep 20.
Opioids have an occasional but high-risk side effect of respiratory depression. The detection of critical respiratory depression usually occurs after the event. Earlier detection would be beneficial in preventing increased morbidity and mortality of 0.01 % patients receiving analgesic opioids. Airway patency during inspiration requires vagal modulation. Regulation of the cardiovascular and respiratory centres may be coupled with a central mechanism that is indirectly measurable with heart rate variability (HRV). While opioids tend to increase parasympathetic tone, a decrease in airway stability could be due to a decrease in respiratory parasympathetic activity. Sympathetic arousal generated by apneic events may separately be recognised with short-term HRV. This pilot observational study examined the dynamic sympathovagal changes during fentanyl-midazolam induced respiratory depression on 10 subjects scheduled for minor surgery. A selection of HRV indices, able to work over sub-minute periods on non-stationary signals, were applied including a range of less common indices. Three analyses tested the effects: post-fentanyl, preceding the first central depression, and preceding obstruction of the upper airway. Statistical significance was assessed with overlap of bootstrap percentile confidence intervals for the median. A decrease in total variability, Lomb Total using the Lomb-Scargle method, is a positive finding for short-term HRV use in this study. No significant change before critical respiratory events was observed in traditional, spectral power, respiratory or other indices. One index, PolVar20, indicated a burst of sympathetic activity preceding respiratory depression similar to sleep apnoea arousals that restore airway patency. Before its usefulness in early detection of airway tone can be determined, PolVar20 requires further work: a statistical method for highly skewed distributions, auto adjustment for baseline variability, and detecting a range of sympathetic responses to apnea.
阿片类药物有偶尔但高风险的呼吸抑制副作用。严重呼吸抑制的检测通常在事件发生后进行。更早的检测对于预防接受镇痛阿片类药物的0.01%患者发病率和死亡率的增加将是有益的。吸气期间气道通畅需要迷走神经调节。心血管和呼吸中枢的调节可能与一种可通过心率变异性（HRV）间接测量的中枢机制相关。虽然阿片类药物倾向于增加副交感神经张力，但气道稳定性的降低可能是由于呼吸副交感神经活动的减少。呼吸暂停事件产生的交感神经兴奋可能可通过短期HRV单独识别。这项前瞻性观察性研究检查了10名计划进行小手术的受试者在芬太尼 - 咪达唑仑诱导的呼吸抑制期间的动态交感 - 迷走神经变化。应用了一系列能够在非平稳信号上进行亚分钟时间段工作的HRV指标，包括一些不太常见的指标。三项分析测试了这些影响：芬太尼给药后、首次中枢性抑制之前以及上气道阻塞之前。使用中位数的自助百分位数置信区间的重叠来评估统计学显著性。使用Lomb - Scargle方法的Lomb Total总变异性降低，是本研究中短期HRV使用的一个积极发现。在传统的、频谱功率、呼吸或其他指标中，在严重呼吸事件之前未观察到显著变化。一个指标PolVar20表明在呼吸抑制之前有一阵交感神经活动，类似于恢复气道通畅的睡眠呼吸暂停觉醒。在确定其在早期检测气道张力的有用性之前，PolVar20需要进一步研究：针对高度偏态分布的统计方法、对基线变异性的自动调整以及检测对呼吸暂停的一系列交感神经反应。
