Журнал «Медицина неотложных состояний» 5(52) 2013

About 4 to 5 % of noncardiac operations involve post-operation cardiovascular complications, of which myocardial infarction is the most threatening one. A significant number of cardiac complications in patients who have undergone surgery due to non-cardiac reasons are a challenge demanding special attention in the post-operation period.

Objective of study. Assessing the cardioprotective capability of total intravenous anaesthesia (TIVA) methods based on data of post-operation monitoring of patients with ischemic heart disease.

Materials and methods. Ninety-two patients with ischemic heart disease who underwent surgery due to diseases of abdominal cavity organs were examined. Three clinical groups were identified: in group 1, TIVA was administered using the basic anaesthetic thiopental sodium; in group 2, TIVA was based on propofol with microdoses of ketamine; in group 3, the basic anaesthetic was ketamine. The average ages of patients were as follows: group 1 – 64.4±1.7; group 2 – 67.9±2.0 and group 3 – 68.9±2.4. To detect myocardium ischemic injury, the level of cardiospecific troponin І (сТnІ) and the N-terminal brain fraction of natriuretic propeptide (NТ-рrоВNР) were determined.

Results and discussion. The haemodynamic profiles of group 1 and 2 patients (anaesthesia based on basic thiopental sodium and propofol) belonged to the hypotonic type with decreasing ventricular ejection and cardiac minute output, and oxygen delivery indicators in the majority of patients. In the third study group, the haemodynamic profile (with ketamine-based anaesthesia) belonged to the eukinetic or hyperkinetic type.

Examination of myocardial ischemia biochemical markers in the blood of group 1 patients with the basic thiopental sodium anaesthetic has shown a clear trend of their increase in the early post-operation period. The level of cardiospecific troponin ТnІ in 24 hours after the operation increased to 0.25±0.05 nM/L, being a credible deviation from initial values. Only in three group 1 patients (10 %) the troponin concentration exceeded 0.5 nM/L.

At all study stages, group 2 patients demonstrated a stable concentration of cardiospecific troponin ТnІ. The ТnІ concentration in group 2 patients was 0.03±0.01 nM/L in 6 hours after the operation, not differing significantly from initial values. In 24 hours, the TnI concentration was 0.05±0.01 nM/L (р < 0.05 as compared to initial data).

The concentration of myocardial ischemia biochemical markers in group 3 patients was stable in 6 hours after the operation and increased as compared to initial data in 24 hours after the operation. The concentration of cardiospecific troponin ТnІ in 24 hours after the operation was 0.1±0.02 nM/L. The ТnІ concentration exceeded 0.5 nM/L only in one patient.

Qualitative evaluation of the precursor of the brain natriuretic propeptide ВNР before the operation in two group 1 patients (%) yielded a positive test. Repeated evaluation in 24 hours after the operation yielded a positive test in 18 patients (60 %) and a negative one in 12 patients (40 %). Before the operation, group 2 patients showed an increasing natriuretic peptide precursor level in two patients (6.7 %). In 24 hours after the operation, the number of BNP–positive patients was three (10 %). Among group 3 patients, in the initial condition, an increasing BNP test was observed in three patients (9.4 %). In 24 hours after the operation, five patients (15.6 %) demonstrated a positive ВNР test.

ECG monitoring of group 1 patients during the operation has demonstrated short-time SТ segment variations in two patients and arrhythmia in five patients. In the first six hours after the operation, segment ST variations were observed in seven patients and arrhythmia in eight 8 patients. ECG monitoring during the operation has demonstrated short-time SТ segment variations in three patients and cardiac irregularity in four group 2 patients. During six hours after the operation, segment ST variations were found in five patients and cardiac irregularity in five patients. Intraoperation ECG monitoring showed transient segment ST variation in three group 3 patients, and two patients showed cardiac irregularity. In the first six hours of the post-operation period, segment ST variations were observed in two patients, and arrhythmia was found in two group 3 patients. In 24 hours after the operation, no pathological changes in the ECG of group 1 to 3 patients were observed.

Conclusions

1. The biggest hazard of development of cardiovascular complications exists in the early post-operation period. This is caused by hypoenergy dynamics and a drop in oxygen condition indicators under conditions of increased metabolic demand.

2. TVA with AVL variants administered for patients with an IHD has a moderate cardioprotective capability with an increasing level of cardiospecific ischemia biomarkers and transient ECG variations.

3. Administering thiopental sodium as a basic TIV anaesthetic during the traumatic stage of the operation demonstrates a tendency of decreasing central haemodynamic and oxygen condition indicators, and a credible increase in cardiospecific ischemia biomarkers, thus increasing the incidence of myocardial ischemia during the early post-operation period.

4. Continuous infusion of 0.005 % ketamine as basic TIV anaesthetic during the traumatic stage of the operation ensures stability of the central haemodynamic and oxygen condition, and is accompanied by a moderately increasing cardiac troponin.

5. Administering propofol in combination with subnarcotic ketamine doses as a basic TIV anaesthetic in the traumatic operation stage was accompanied by minor variations in the level of myocardial ischemia cardiospecific biomarkers.