Monitoring of the electrocardiogram (ECG) in anesthesiology is one of mandatory requirements of basic anesthesiology monitoring. The requirement to monitorirovat at least one assignment of the electrocardiogram is included into standards of monitoring of many countries. Need of monitoring of an ECG it is caused by importance of this indicator which reflects electric activity of heart and allows to diagnose and treat quickly various medical emergencies.
Monitoring of an ECG has to be carried out regardless of a type of the carried-out anesthesiology grant, whether it be the general or regional anesthesia.
For implementation of monitoring of an ECG during anesthesia special monitors which usually are multipurpose are used, that is allow to display in addition to an ECG also some other monitoring indicators. It is rather convenient as allows to trace at the same time trends of various indicators, for example, of an ECG and photoplethysmograms together with digital values of saturation of hemoglobin of an arterial blood oxygen. It can be very useful to complex diagnostics of various situations arising on the course of carrying out an anesthesiology grant.
Standardly monitoring of an ECG during anesthesia is carried out with use of the second standard lead. It is connected with the fact that the second standard lead allows to trace a rhythm source better. If necessary, additional assignments, for example, chest can be used. It can be used for diagnostics of intraoperative ischemia of a myocardium at patients with coronary heart disease. Anyway, monitoring of an ECG is made by means of flexible electrodes which are attached by means of the special velcros which are pasted to a body of the patient with a conducting layer. It should be noted that the arrangement of these velcros should not interfere with access to a thorax of the patient and also should not cover a surgery field. Standardly for monitoring of an ECG in one assignment (second) place three electrodes: on the front surface of shoulder joints and on the average axillary line. The red electrode is placed on the right above (on the front surface of the right shoulder joint), yellow — at the left above (on the front surface of the left shoulder joint) and green — at the left below (at the level of the sixth or seventh mezhreberye on the average axillary line at the left).
It is important to adjust also correctly the monitor for exact display of electric activity of heart. Adjust the level of strengthening of a signal that the picture was readable and allowed to define a rhythm source. Excessively high level of strengthening will lead to numerous hindrances. It is also useful if the monitor has protection against hindrances when carrying out diathermocoagulation. The monitor carries out calculation of heart rate by means of the most acting teeth therefore it is necessary to remember that the heart rate displayed by it can not correspond to the ECG of a certain form, real in the analysis. In the analysis of an ECG during anesthesia pay attention first of all to a heart rhythm source, to heart rate and also to a form and size of various elements of an ECG complex.
The normal sinoatrial rate is characterized with a frequency from 60 to 100 beats per minute, existence of a tooth of P before each ventricular complex and also a regular rhythm. Reduction of heart rate less than 60 in a minute is called bradycardia, increase more than 100 in a minute — tachycardia. If heart rate exceeds 150 in a minute, as a rule, it is not a sinoatrial rate.
In addition to sinus, the atrial rhythm, a ciliary arrhythmia (fibrillation of auricles) and also a rhythm from AV-connection can meet. All of them are pathological rhythms and require the corresponding attention from the anesthesiologist.
In the analysis of arrhythmias it is necessary to pay first of all attention to QRS complex width — a wide or narrow complex and also to a condition of a hemodynamics of the patient. Width of a complex and a condition of a hemodynamics has basic value for the choice of the subsequent tactics of treatment of arrhythmia.
In the analysis of an ECG regarding detection of intraoperative ischemia of a myocardium, first of all pay attention to ST segment and also to a form and the direction of a tooth of T. At a depression of a segment of ST subendocardial ischemia of a myocardium is observed, at its elevation - transmural ischemia. T tooth at ischemia usually changes together with a segment of ST and becomes negative or takes a two-phase form. Localization of the site of ischemia is established by means of a white ECG electrode, placing it in necessary chest assignment.