接上篇：小儿脑电图最低技术标准（二）

 

 

 

2.5 (MTR 3.1) 在新生儿，必须要使用2个或更多的信道用来记录非脑电的多形性变异波，推荐采用以下几种导联组合：

 

 

这些导联组合的设置是基于使用有16个信道设备的基础上，其中4个信道用于记录非脑电的多种不同的生理活动波，剩下12个信道用于记录脑电。A和B是10-20系统完整的导联组合；而C是减少了的导联组合。在导联组合B和C中可以用Fp3和Fp4替代Fp1和Fp2，用M1和M2替代A1和A2。A和B是10-20系统完整的导联组合；而C是减少了的导联组合。在导联组合B和C中可以用Fp3和Fp4替代Fp1和Fp2，用M1和M2替代A1和A2。

 

虽然以上导联组合方式并不意味着是唯一可以使用的导联组合方式，但它被视为是一种标准的导联组合，为了给脑电图工作室之间提供标准化的参考，在所有工作室中应至少采用其中一个标准化的导联组合方式，作为新生儿脑电图记录中的一部分。导联组合C包括了中线电极，它对早产儿的记录特别有帮助。在所有情况下Cz均应包括在内，因为正相的“rolando”尖波(一个常见的病理现象)可能仅出现在这一人群的Cz部位。也可为特殊目的设计其他不同的导联组合，甚至参考电极与头皮——头皮电极相连的导联组合对新生儿来说也是可以接受的。

 

在新生儿的脑电记录中仅使用单一的导联组合通常是足够的，许多实验室都是这样做的，然而这并不意味着单一的导联组合就完全足够了，甚至在偏好单一导联组合的实验室中，必要时，如为了更好的描述单病灶的异常也应增加额外的导联组合。为了记录多形性变异波，建议使用以下的电极：（1）记录眼动(EOG)：用E1-A1和E2-A1，或E2-A1。和E2-A2；（2）记录下颏肌电(EMG)：在下颏中线的两边1～2 cm处放置两个电极；（3）记录心电图(ECG)：导联1(右上肢一左上肢)是最佳的。如果正在记录下颏肌电的同时仅对心率感兴趣，可以省略ECG信道，因为R波经常出现在肌电信道上。

 

2.6 (MTR 3.2) 住院的小儿脑电图记录前，特别是对一些处于危险状况以致必须行床边脑电图检查的小儿而言，技术员应向护士详细了解患儿的情况和记录过程中的任何限制。

 

婴儿出生时的妊娠龄和孕龄(出生时的妊娠龄加上出生后的时间)对脑电图的解释至关重要，所以必须在给脑电图医生提供的信息中包括按时间计算的出生后年龄，它以周数来表示。其他相关的临床信息(包括血气分析、血电解质、目前的治疗)也应该提供给脑电图医生参考。

 

2.7 (MTR 3.4) 在小婴儿中，最合适的灵敏度是7μV／mm，但比年长的患儿更需要经常调整。至少要有部分记录以合适的灵敏度来显示低幅快活动。低频滤波一般采用0.3 Hz或0.6 Hz(-3 dB)(相当于时间常数0.27 s或0.53 s)，而不是通常使用的1Hz(0.16 s)。

 

通常建议使用与相应脑电图一致的灵敏度和时间常数(7μV／mm)来记录眼动(EOG)。对于呼吸电图来说，应该调整放大器到能产生一个明确可见的垂直偏转，其低频滤波也应设置在0.3 Hz或0.6 Hz，但不要使用直流电。对于下颏肌电(EMG)的记录，推荐采用3μV／mm的灵敏度，低频滤波设置在5Hz(相当于时间常数0.03 s)，高频滤波设置在70Hz。

 

2.8 (MTR 3.9，3.12) 如果有可能的话，最好安排在喂养期间行脑电图检查，已经安装完电极后开始喂养患儿，在患儿喂养完毕，想睡觉时开始记录。

 

对于新生儿来说，需要记录更长的时间，这是因为患儿在清醒时有大量的活动和其他生理伪差而导致记录时间的丢失，为了有足够量的记录去评价睡眠——觉醒周期和其他状态，经常需要增加额外的记录时间。

 

除非脑电图是极不正常的，否则20～30 min的脑电记录时间通常是不够的。对于脑电图表现恒定的新生儿来说，可能至少需要60min的记录时间来证实脑电图记录没有变化，其余的患儿要充分记录到两种主要的睡眠状态。新生儿初始睡眠期通常是主动睡眠，可能持续时问非常短或持续数分钟。

 

充分的睡眠记录应当包括整个安静的睡眠。对新生儿而言，我们绝无必要和尝试使用镇静药物来获得睡眠脑电记录。即使可行，重复闪光刺激也很少用于临床新生儿的脑电检查，不推荐使用。

 

2.9 (MTR 3.13) 在每一种导联组合开始记录时，都应标明患儿的状态，包括头和眼睑的位置。对于新生儿而言，技术员对患儿的持续观察和频繁的标记尤为重要。

 

对于昏迷、昏睡和脑电表现为任何一种固定模式的患儿来说，应在记录中给予系统的视觉、听觉、躯体感觉刺激，但最好应在记录的末期实施，以免干扰正常的睡眠周期或产生不期望的觉醒伪差而使此后的描记难以阅读。应该在最接近刺激的时点尽可能记录患儿对刺激的临床反应。

 

英文原文

2.5 (MTR 3.1) In neonates in whom two or more channels must be devoted to polygraphic variables, the following montages are recommended:

 

These are based on the assumption that a 16-channel instrument is used with 4 channels devoted to polygraphic variables, leaving 12 channels for EEG. Montages A and B are for full 10-20 System electrode arrays: Montage C for the reduced array. In Montages B and C, Fp3 and Fp4 may be substituted for Fp1 and Fp2 and M1 and M2 may be substituted for A1 and A2.

 

It is not implied that the above montages are the only ones that can be used. Rather, they should be considered standard montages, and at least one of them should be used for at least a portion of a neonate’s EEG recording in all laboratories, to provide some standardization among laboratories. Since Montage C includes the midline, it can be particularly helpful when recording premature infants. In any case, Cz should always be included because positive “rolandic” sharp waves (a common pathologic finding) may occur only in Cz in this population. Various other montages can be devised for special purposes. Even a montage combining referential and scalp-scalp derivations is acceptable for neonatal EEGs.

 

The use of a single montage throughout a recording of a neonate may be, and often is, sufficient, and is preferred in many laboratories. It is not implied, however, that a single montage is always adequate. Even in laboratories preferring single montages, additional montages should be used when the need arises; for example, to better delineate unifocal abnormalities.

 

For recording polygraphic variables, the following derivations are recommended: (1) For eye movements (EOG): use E1-A1 and E2-A1 or E2-A1 and E1-A2. (2) For submental EMG: two electrodes under the chin, each 1-2 cm. on either side of the midline. (3) For EKG, lead 1 (right arm-left arm) is preferred. If submental EMG is being recorded and if only heart rate is of interest, the EKG channel can often by omitted because the R wave is usually visible in the EMG channel.

 

2.6 (MTR 3.2) Before recording the EEGs of inpatients, especially those in so precarious a condition that the recording must be done at bedside, the technician should consult with the nursing staff concerning the patient’s condition and any limitations on recording procedures.

 

The baby’s gestational age at birth and conceptional age (gestational age at birth plus time since birth) on the day of recording, stated in weeks, are absolutely essential to interpretation and must be included,together with chronological age since birth in the information available to the electroencephalographer.

 

All other available relevant clinical information (including concentration of blood gases, serum electrolyte values, and current medications) should be noted for the electroencephalographer’s use.

 

2.7 (MTR 3.4). In young infants’ EEGs, the most appropriate sensitivity is usually 7 μV/mm, but adjustments up or down are more often needed than in the case of older patients. At least a portion of the recording should be run at a sensitivity adequate to display low-voltage fast activity. The low-frequency filter setting should be between 0.3 and 0.6 Hz (-3 dB) (time constants of 0.27-0.53 s), not the commonly used 1 Hz (0.16 s).

 

For EOG, a sensitivity of 7 μV/mm and the same time constant as for the concomitantly recorded EEG derivations are recommended. For respirogram, amplification should be adjusted to yield a clearly visible

vertical deflection, and a low-frequency filter setting of 0.3-0.6 Hz, but not direct current (DC), should be used. For the submental EMG recording, a sensitivity of 3 uV/mm, a low-frequency filter setting of about 5 Hz (time constant of about 0.03 s), and a high-frequency filter setting of 70 Hz should be employed.

 

2.8 (MTR 3.9, 3.12). If possible, it is advantageous to schedule the EEG at feeding time and arrange to feed the child after the electrodes have been applied, but before beginning the recording, as babies tend to sleep after feedings.

 

Allow for extra recording time for the EEGs of neonates. Time is commonly lost due to a greater number of movement and other physiologic artifacts during wakefulness, and extra time is usually needed in order to obtain sufficient recording to permit evaluation of stages of the wake-sleep cycle and other states.

 

Except when the EEG is grossly abnormal, 20- or 30-min. recordings are usually insufficient. In those neonates in whom patterns appear to be invariant, it may be necessary to obtain at least 60 min. of recording to demonstrate that the tracings are not likely to change. In the rest, adequate sampling of both major sleep states is important. The initial sleep state in the neonate is usually active sleep, which may last a very short time or continue for many minutes. An adequate sleep tracing must include a full episode of quiet sleep.

 

It is never necessary or desirable to use sedation to obtain a sleep recording in a neonate.

 

Repetitive photic stimulation is rarely, if ever, clinically useful in neonates, and is not recommended.

 

2.9 (MTR 3.13) The child’s condition, including head and eyelid position, should be clearly indicated at the beginning of every montage. Continuous observations by the technologist, with frequent notations on the recording, are particularly important when recording from neonates.

 

In stuporous or comatose patients and in those showing invariant EEG patterns of any kind,visual, auditory, and somatosensory stimuli should be applied systematically during recording,but only toward the end of the recording period, lest normal sleep cycles be disrupted or unexpected arousal-produced artifact render the tracings unreadable thereafter. The stimuli and the patient’s clinical responses or failure to respond should be noted on the recording as near as possible to their point of occurrence.

 

翻译：秦兵

编辑：格格