Simmons L E, Riker R R, Prato B S, Fraser G L
Department of Critical Care, Maine Medical Center, Portland 04102, USA.
Crit Care Med. 1999 Aug;27(8):1499-504. doi: 10.1097/00003246-199908000-00016.
To describe the level of sedation for a cohort of mechanically ventilated adult intensive care unit (ICU) patients using validated subjective and objective tools.
Prospective convenience sample.
Multidisciplinary 34-bed ICU at Maine Medical Center, a 599-bed nonuniversity, academic medical center.
Sixty-three adult ICU patients were monitored during 64 episodes of ventilatory support.
Patients were prospectively evaluated by one trained investigator using the revised Sedation-Agitation Scale (SAS) and were simultaneously monitored for 1 to 5 hrs using the Bispectral Index (BIS), a numeric scale from 0 to 100 derived from the electroencephalogram. BIS values were assigned to baseline, stimulated, and average conditions for each patient by a separate investigator blinded to SAS scores. Ventilator settings, medications, and the lung injury severity (LIS) score were also recorded. Sedation levels varied from very deep sedation (SAS score = 1, BIS score = 43) to mild agitation (SAS score = 5, BIS score = 100). Heavily sedated patients (SAS score = 1-2, n = 20) had higher FIO2 (0.52 vs. 0.42, p = .008), oxygenation index (9.4 vs. 5.4, p = .03), and LIS scores (1.3 vs. 0.7, p = .004) and lower baseline (66 vs. 78, p = .01), average (66 vs. 81, p < .001), and stimulated (89 vs. 96, p = .016) BIS scores compared with more awake patients. Patients with intermittent neuromuscular blockade use (n = 4) had higher FIO2 (0.65 vs. 0.44, p = .006), minute ventilation (14.6 vs. 9.9 L/min, p = .005), positive end-expiratory pressure (7.5 vs. 4.8 cm H2O, p = .05), oxygenation index (15.7 vs. 6.0, p < .001), and LIS scores (3.3 vs. 1.0, p = .036) and were more sedated, with higher suppression ratios (3.5 vs. 0.6, p = .05) and lower SAS scores (1.5 vs. 4, p = .035). The average BIS values correlated well with SAS (r2 = .21, p < .001).
SAS and BIS work well to describe the depth of sedation for ventilated ICU patients. Deeper sedation and intermittent neuromuscular blockade were used for patients with greater ventilatory requirements and more severe lung disease. The correlation between subjective and objective scales varied in medical, surgical, and trauma patients. Further research with SAS and BIS may facilitate the development of quantitative sedation guidelines for the ICU.
使用经过验证的主观和客观工具描述一组接受机械通气的成年重症监护病房（ICU）患者的镇静水平。
前瞻性便利样本。
缅因医疗中心的一个拥有34张床位的多学科ICU，该中心是一家拥有599张床位的非大学学术医疗中心。
在64次通气支持期间对63名成年ICU患者进行了监测。
由一名经过培训的研究人员使用修订后的镇静-躁动评分量表（SAS）对患者进行前瞻性评估，并同时使用脑电双频指数（BIS）进行1至5小时的监测，BIS是一个从脑电图得出的0至100的数字量表。另一名对SAS评分不知情的研究人员为每位患者的基线、刺激状态和平均状态分配BIS值。还记录了呼吸机设置、用药情况以及肺损伤严重程度（LIS）评分。镇静水平从深度镇静（SAS评分=1，BIS评分=43）到轻度躁动（SAS评分=5，BIS评分=100）不等。深度镇静患者（SAS评分=1-2，n=20）的FIO2较高（0.52对0.42，p=0.008）、氧合指数较高（9.4对5.4，p=0.03）、LIS评分较高（1.3对0.7，p=0.004），与较清醒的患者相比，其基线（66对78，p=0.01）、平均（66对81，p<0.001）和刺激状态（89对96，p=0.016）的BIS评分较低。使用间歇性神经肌肉阻滞剂的患者（n=4）的FIO2较高（0.65对0.44，p=0.006）、分钟通气量较高（14.6对9.9L/分钟，p=0.005）、呼气末正压较高（7.5对4.8cmH2O，p=0.05）、氧合指数较高（15.7对6.0，p<0.001）、LIS评分较高（3.3对1.0，p=0.036），且镇静程度更高，抑制率更高（3.5对0.6，p=0.05），SAS评分更低（1.5对4，p=0.035）。平均BIS值与SAS相关性良好（r2=0.21，p<0.001）。
SAS和BIS能很好地描述通气ICU患者的镇静深度。对于通气需求更大和肺部疾病更严重的患者，采用了更深的镇静和间歇性神经肌肉阻滞。主观和客观量表之间的相关性在内科、外科和创伤患者中有所不同。对SAS和BIS的进一步研究可能有助于制定ICU的定量镇静指南。
