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811. Брюханов В.М., Зверев Я.Ф., Лампатов В.В. и др. Методические подходы к изучению функции почек в експерименте на животных // Нефрология, 2009. - Том 13, № 3. - С. - 52-62.
12. Докшшчт дослщження лшарських засобiв: методичт рекомендацл [за ред. О. В.Стефанова] - К.: Авщена, 2001. - 528 а
13. Лапач С. Н. Статистика в науке и бизнесе / С. Н. Лапач, А. В. Чубенко, П. Н. Бабич. -К.: Морион, 2002. - 640 с.
PECULIARITIES OF CEREBRAL BLOOD-GROOVE WHILE PROVIDING ANESTHESIA TO PATIENTS OF ADVANCED
AND SENILE AGE
Loskutov O. A.
Druzhyna A. N.
Ukraine, Kyiv, Chair of «Anesthesiology and Intensive Therapy» Shupyk National Medical
Academy of Postgraduate Education
Abstract. Work is devoted to studying of dynamics of a brain blood-groove in the pool of an average brain artery at operations with cardiopulmonary bypass on patients of advanced and senile age and to identifying the factors influencing its speed parameters.
27 patients at the age of 69,3±4,5 years operated on coronary artery bypass surgery in the conditions of cardiopulmonary bypass were researched.
During work it is established that in the studied group, initial indicators of a brain blood-groove were 53,9±0,6% less in comparison with the standard values for this category ofpatients.
Decrease in volume speeds of a cerebral blood-groove (by 46,7±2,5% of rather initial size) was noted at an induction stage in anesthesia and at a stage of connection of the cardiopulmonary bypass and the beginning of hypothermia (by 64,2±3,9% of initial values).
During perfusion, at the laminar and pulsing modes of artificial blood circulation, it wasn't observed a reliable difference in indicators of average linear speed of blood-groove in the pool of an average and brain artery. And the size of cerebral perfusion was influenced authentically by productivity of the cardio-pulmonary bypass.
Keywords: coronary artery bypass surgery, cardiopulmonary bypass, advanced and senile age, brain blood-groove.
Introduction. Brain damage is first in the list of postoperative complications at cardiovascular surgery and as usual reveals in a specter of disorders such as ischemic stroke, delirium and cognitive dysfunction [1].
Ischemic stroke (as the result of air or physical embolism, or hypo-perfusion) is the most significant clinical manifestation of neurological damage of the central nervous system (CNS) and is diagnosed of 1% - 3% patients operated on with cardiopulmonary bypass (CB) [1, 2].
Postoperative delirium is one of the frequently developed complications, in particular, among patients at advanced age. In general surgery this pathological condition is diagnosed with frequency ranging from 10% to 18%, in orthopedic-trauma surgery it is observed in 13% - 41% cases and at open-heart surgery it is registered as frequent as 44,31% [3,4]. Delirium increases patient's stay in hospital from 5 to 10 days [5], which according to Leslie D.L. and coauthors means cost increase on average by $16000 per patient [6]. Moreover in 35% - 40% cases delirium is a reason of fatality during the first half year after the operation [7].
Cognitive dysfunction is the usual postoperative neurological complication in cardiovascular surgery diagnosed of 30% - 65% patients within 1 month after myocardial revasculization and of 20% -40% patients during the next postoperative months [8]. This notion includes cognitive disorders developing at an early period and remaining at a late postoperative period which clinically reveal by disturbed memory and other higher cortex functions (thinking, speech), and also concentration difficulties proved by the data of neuropsychological testing [9]. It should be noted that cognitive dysfunction after general surgery with general anesthesiology is observed at every age range group of patients [10].
It is quite obvious that for prophylaxis of intraoperative damage of CNS to maintain adequate cerebral circulation is of utmost importance. It is conditioned by the fact that nervous tissue has no energy in store and has not enough possibilities to provide energy by anaerobic glycolysis either. It is the main reason why brain can only «bear» a very short period of hypo-perfusion after which neurons are damaged irreparably [11].
Maintaining adequate brain perfusion is vital at anesthetic operation on patients of advanced age. As it has been noted in the works of many authors [12,13], with age, atherosclerotic vascular involvement and arterial hypertension (AH) added there is indices drop of cerebral hemodynamics and autoregulatory possibilities of cerebral circulation which facilitate cardiovascular responses making them inert and torpid. Circulatory hypoxia appears on this background which under unfavorable conditions can bring to breakdown of cerebral circulation and metabolism disorder [12,13].
The goal of this work is to research dynamics of cerebral blood-groove in the pool of epy medial cerebral artery (MCA) during operations with cardiopulmonary bypass on patients of advanced and senile age and to identify factors influencing influencing its speed parameters.
Materials and methods. 27 patients with ischemic heart disease (IHD) who were operated on coronary artery bypass surgery (CABS) with suturing 2 or 3 (average number 2,4±0,3) coronary artery venous anastomoses with cardiopulmonary bypass (CB) in SU «University of Heart of MHC of Ukraine»were included in the research.
The average age range of the examined patients was 69,3±4,5 years old, the average weight was 82,5±7,4 kg. Where there were 22 men (81,5%), and 5 female (18,5%).
Depending on the functional class (FC) of stenocardia all patients were divided as follows: II FC - 5 people (18,5%), III FC - 16 people (59,3%), IV FC - 6 people (22,2%).
17 (63%) patients had one myocardial infarction (MI) 4 (14,8%) patients - two MI in the past. 6 (22,2%) of examined patients had IHD without MI in history.
Left ventricular injection fraction (IF) was higher than 40% of 21 (77,8%) patients and lower than 40% of 6 (22,2%) people.
At the preoperative stage duplex scanning of great neck vessels did not indicate any significant hemodynamic stenosis of general carotid or internal carotid artery of all patients in the researched group.
Diabetes of 2d type was diagnosed of 8 people (29,6%), arterial hypertension was registered of 21 patients (77,8%).
All patients were operated on in conditions of general anesthesia based on sevofluran (1,5-2 MAC). Introduction anesthesia consisted of propofol (1,5±0,3 mg/kg) and phentanilum (1 mkg/kg). Myorelaxation was supported by pipecuronium bromide (0,07 - 0,08 mg/kg), further analgesia - by phentanilum (21,5±3,4 mkg/kg during the operation time period).
Artificial pulmonary ventilation of the examined patients was done with air-oxygen mixture (FiO2=50%) on normal ventilation controlling blood gas composition (average value pC02 of artery blood was 35,3±2,4 mm HG).
Cardiopulmonary bypass was done with the device «System 1» (Terumo, USA), using membrane oxygenators «Affinity» (Medtronic, USA) in conditions of medium hypothermia (T=32°C). Cardiopulmonary bypass before artificial heart fibrillation was conducted using laminar regime with further turn into pulse regime (perfusion index was 2,4 - 2,5 l/min/m2, perfusion volume speed was 4,5±0,02 l/min on average). During CPB normovolemic hemodelution was used at the average level of hemotacrit 29,5±3,4%, hemoglobin 90,1±2,4 g/l and lactate average level 1,8±0,43 mmole/l. Blood coagulation was controlled by activated coagulation time maintaining it within 480 - 600 seconds. Perfusion adequacy was evaluated by indices of acid-based status, gas and electrolyte blood composition, diuresis rate, esophageal-rectal temperature gradient.
The following values were under control: ECG, invasive artery and central venous pressure, saturation by pulsotachometer. All patients were intraoperatively assessed for anesthesia depth with monitor use «VISTA» (Aspect Medical System Inc, USA). The electro-encephalography was registered in frontal branches as recommended by the firm maker with further calculation of bispectral index (BIS) (ver 3.1). The average value BIS in the group under research was 43,7±4,5%.
To register quantity parameters of coronary blood-groove in the pool of MCA the patients were conducted transcranial Doppler's tomography (TCDT) with an ultra-sound machine «Angiodin 2K» («Bios», Russia). Measures were done transtemporally by a standard method [14]. Base evaluation of linear values of blood-groove was done on the operation eve and later at the intraoperative stage beginning from initial narcosis. Ultra-sound sensors of linear format with frequency diapason 5-10 MHz were used.
Results and discussion. 21 examined patients whose IF was 52,7±4,3%, the average linear speed in the pool of MCA before initial narcosis was identified within 54,2±7,6 sm per second (see Figure) and was by 53,9±0,6% less in comparison with standard values for people from 35 to 50 years old (p=0,0237) [14].
Dropping of registered values of linear speed in the MCA pool which we indicated correlate to the data of P.N. Ainslie and S. Demirkaya with coauthors's research [15,16], who say that cerebral circulation reduces with age by 25% -30% within the age range period from 20 to 80 years old.
Speed parameters drop of cerebral circulation of the examined patients with preserved left ventricular IF (over 40%) can be explained by involution of vessels tonus of central cerebral arteries and dysfunction of vessels autoregulation.
Fig. 1. Dynamics of mean arterial pressure (MAP) values and linear blood-groove , medium coronary artery (MCA) at different stages of research
in the pool of
At the stage of anesthesia induction the mean artery pressure (MAP) of all patients decreased by 32,2±1,2% and was 63,3±4,1 mm HG (see Figure). With a reliable drop of MAP (p=0,0372) it was noted depression of linear blood-groove speed in the MCA pool which was 28,9±2,95 sm per second (46,7±2,5% in relation to initial value (p=0,0139)) (see Figure). That is in percentage reduction of speed values of cerebral circulation was by 14,5±1,3% higher in comparison with MAP percentage drop registered at this stage of research.
Further research showed that at the stage of anesthesia maintenance the indices of MAP and cerebral blood-groove were stabilized and close to initial values (see Figure).
Decrease in volume speeds of a cerebral blood-groove which on average was 34,8±2,64 sm per second was noted at an induction stage in anesthesia and after connection of the cardiopulmonary bypass and the beginning of hypothermia (by 64,2±3,9% of initial values) (see Figure) .
The main stage of myocardial revasculization in conditions of design value of perfusion volume speed was characterized by stabilization of the researched values. Mean linear speed of blood-groove in the MCA pool was registered within 47,6±3,1 sm/sec (78,6±9,2% by initial values) (see Figure).
During perfusion, at the laminar and pulsing modes of artificial blood circulation, it wasn't observed a reliable difference in indicators of average linear speed of blood-groove in the pool of MCA (p=0,758).
During CB the drop of MAP was registered of 19 patients (70,4% cases) which required therapy correction. For this purpose 10 patients were injected bolus intravenous micro-doses of mesaton and 9 people increased perfusion volume speed by 20% of initial to maintain MAP at an adequate level.
Analysis of the obtained data showed that increase of MAP due to bolus intravenous injection of 0,4 - 0,5 ml 0,01% mesaton solution provided rise of artery pressure on average by 45,8±4,5% (from 36,5±2,4 mm HG to 67,4±3,1mm HG). MAP rise provided increase of linear speed of blood-groove in the MCA pool on average by 19,3±3,1%. Perfusion volume speed increase by 20% from initial value was accompanied by a reliable rise of blood-groove speed in the MCA pool on average by 48,5±3,32% (from 32,1±3,5 mm HG to 62,3±5,2 mm HG) and accordingly lead to increase of cerebral
circulation on average by 36,4±2,9%. Thus, during CPB the cerebral circulation is more dependent on perfusion volume speed than on MAP value.
After the main stage of the operation was finished, cardiac-resuscitation and normal temperature restored we observed stabilization of linear speed of blood-groove in the MCA pool and its progressive increase to 67,7±4,1 sm per second which was higher than previous values by 29,7±2,1%, and initial values - by 19,9±2,5% on the background of lesser corresponding MAP values (see Figure).
As it has been noted above the main part of the examined patients was constituted by patients with AH (77,8%). This category of patients is very sensitive to «hemodynamic oscillations» as the result of micro-circulation pathological changes with AH in the background.
According to P.A. Lebedev and coauthors [17] if capillary vessels are affected with high pressure for a long time the lumens of resistant vessels narrow and in some cases fully close because of contraction of precapillary sphincters. При этом Density lessening of lumens cross-section of capillary vessels is accompanied with increase of vessels reactivity. Consequently constriction of micro-vessel with lack of perfusion results in disappearance of non-perfused vessel bringing to the second stage that is structural or anatomic sparseness which can be preserved even at maximum vasodilation [17]. As it is noted in foreign authors' researches endothelia dysfunction, reduction of aortic vessel flexibility and big elastic arteries is characteristic for AH with increase of pulse wave spread, post-load of left ventricle and development of cardiovascular remodeling processes shown in rise of peripheral vessels resistance [18,19].
Polymorphus structural changes of micro-circular cerebral stream called «hypertonic angioencephalopathy» are observed with AH [20]. In cerebral vessels of brain destructive changes take place (plasmorrhagia into the vessel wall with swallowing and sharp narrowing of the lumen even to its complete obliteration and formation of hypertonic stenosis, development of military aneurysms), and also processes directed to adaptation (hyperelastosis, vessels requalification). Plasmatic soaking of arterioles and small arteries develop because of hypoxic damage of endothelium, its membrane, and muscular cells and walls fiber structure due to the vessel spasm [20]. The elements of wall destruction, so as proteins and lipids soaking it, are resorbed by macrophages but this resorption is usually incomplete. Arterioles hyalinosis or arteriosclerosis develops. Analogical changes appear in small vessels of muscular type. Arteries with thin walls which have no medium membrane are one of the most frequent types of cerebral vessels changes with AH [20].
To regulate AH at conducting operations the mentioned above categories of patients must be given hypotensive medications of controlled and predicted effect. According to European register on treating acute hypertension (Euro-STAT), based on observation research in 11 hospitals of 7 European countries (Austria, Belgium, Germany, Italy, Spain, Sweden and United Kingdom), the most frequently used medication to AP correction during general anesthesia is Urapidil (Ebrantil) [21].
This medication is of central and peripheral effect mechanism. At the peripheral level Urapidil (Ebrantil) blocks mostly postsynaptic ai-adrenoreceptors. At the central level it modules activity of blood circulation center which prevents tonus rise of the sympathetic nervous system and decrease tonus of bloodstream. Intravenous injection of Urapidil (Ebrantil) leads to drop of systolic and diastolic value of blood pressure by decrease of general peripheral vessel resistance. The heart rate remains unchangeable and medication effect id predicted and dose dependent.
In the work of Grabowska-Gawel A. and coauthors the effcts of Urapidil (Ebrantil) were researched at different surgery types [22]. As the result it was proved that mono-therapy with Urapidil (Ebrantil) (an average intravenous dose of 26,3±2,4 - 30,5±3,5 mg) was more effective of 81,1% patients. The rest 18,9% required additional intravenous injection of nitroglycerine which was demanded by the clinical situation connected with manipulations on the abdominal aorta [22].
According to Zapolskaia Y.A.'s research [23], providing anesthesia to patients with AH reduction of artery stream, increase of cerebral vessels tonus was observed and of 72% patients it was diagnosed interhemispehric asymmetry of bloodstream with left hemisphere deficit dominating.
Taking into consideration all said above it is of special interest the survey of 85 anesthetists as to reasons to deepen anesthesia at operative surgery [24], according to which in в 20% cases additional introduction of hypnotic medications was done to increase effect of muscular relaxants and in 30,6% - to reduce arterial pressure in order to lessen bleeding, in 20% -at the «painful» stage of the operation, in 75,3% - in case of heart rate increase and in 100% cases all doctors deepened anesthesia at rise of AP independent on the operation stage [24]. However according to our previous research published before [24], deepening anesthesia to regulate intraoperative AP increase can be a risk factor of postoperative cognitive dysfunctions which is very likely connected with cerebral circulation depression. Though the latter opinion needs further researching and proving, the results of this work
emphasize pathophysiological suitability to use Urapidil (Ebrantil) of patients with AH at conducting anesthesia at operative surgery.
Conclusions. 1. During the research it was established that with age advance accompanied with atherosclerosis and long-time AH cerebral circulation, reactivity and autoregulatory change diapason of cerebral vessels lumens drop.
2. Conducting the main stage of cardiac surgery in conditions of CB to provide adequate cerebral blood-groove the value of perfusion volume speed must be maintained at the level of 120% from initial whereas MAP value can be less than 70 mm HG without the risk of cerebral hypo-perfusion.
3. Introducing technique of transcranial Doppler's tomography into clinical practice gives a possibility to evaluate qualitative and quantitative parameters of cerebral circulation in intracranial arteries but also to indicate cerebral vascular reactivity, to assess autoregulation of cerebral blood-groove reflecting vessels resistance, to prevent cerebral hyperfusion and to reduce percentage of neurologic complications.
4. To correct high arterial pressure during general anesthesia it is necessary to use medications with controlled and predicted antihypertensive effect giving preference to Urapidil (Ebrantil).
REFERENCES
1. The preoperative neurological evaluation / J.Probasco, B.Sahin, T.Tran, [et al] // Neurohospitalist. -2013.- Vol.3, №4.- Р. 209-220.
2. Hogue C.W. Cardiopulmonary bypass management and neurologic outcomes: an evidence-based appraisal of current practices / C.W.Hogue, C.A.Palin, J.E.Arrowsmith // Anesthesia & Analgesia.- 2006.- Vol.103 (Issue 1).- Р. 21-37.
3. Postoperative delirium after elective orthopedic surgery / A.M.Contin, J.Perez-Jara, A. Alonso-Contin, [et al] // Geriatr. Psychiatry.- 2005.- Vol.20, №6.-Р. 595-597.
4. Prevalence of delirium in opium users after coronary artery bypass graft surgery / N.Eizadi-Mood, O.Aghadavoudi, M.R.Najarzadegan, [et al] // Int. J. Prev. Med.- 2014.- Vol.5, №7.- Р. 900-906.
5. Allen S.R. Postoperative complications: delirium / S.R. Allen, H.L.Frankel // Surg. Clin. North. Am.- 2012.- Vol.92, №2.- Р. 409-431.
6. One-year health care costs associated with delirium in the elderly population / D.L.Leslie, E.R.Marcantonio, Y.Zhang, [et al] // Arch. Intern. Med.- 2008.- Vol.168, №1.- Р. 27-32.
7. Inouye S.K. Delirium in older persons / S.K.Inouye // N. Engl. J. Med.- 2006.- Vol.354, №11.- Р. 1157-1165.
8. A randomized comparative study of patients undergoing myocardial revascularization with or without cardiopulmonary bypass surgery: The MASS III Trial / W.Hueb, N.H.Lopes, B.J.Gersh, [et al] // Trials.- 2008.- Vol.28, №9.- Р. 52-58.
9. Postoperative cognitive dysfunction after noncardiac surgery: a systematic review / S.Neuman, J.Stygall, C.Hurani, [et al.] // Anesthesiology.- 2007.- Vol.106, № 3.- P. 572-590.
10. Predictors of cognitive dysfunction after major noncardiac surgery / T.G.Monk, B.C.Weldon, C.W.Garvan, [et al.] // Anesthesiology.- 2008.- Vol.108, №1.-P. 18-30.
11. Markus H.S. Cerebral perfusion and stroke / H.S.Markus // J. Neurol. Neurosurg. Psychiatry.- 2004.- Vol.75, №3.- Р. 353-361.
12. Elevation in cerebral blood flow velocity with aerobic fitness throughout healthy human ageing / P.N.Ainslie, J.D.Cotter, K.P.George, [et al.] // J. Physiol.- 2008.- Vol.586, №16.- Р. 4005-4010.
13. Normal blood flow velocities of basal cerebral arteries decrease with advancing age: a transcranial Doppler sonography study / S.Demirkaya, K.Uluc, S.Bek, [et al.] // Tohoku J. Exp. Med.-2008.- Vol.214, №2.- Р. 145-149.
14. Транскраниальная допплерография в интенсивной терапии Методическое пособие для врачей / [А.А. Белкин, А.М. Алашеев, С.Н. Инюшкин].- Петрозаводск: Интел Тех, 2006.- 103 с.
15. Elevation in cerebral blood flow velocity with aerobic fitness throughout healthy human ageing / P.N. Ainslie, J.D. Cotter, K.P. George, [et al.] // J. Physiol.- 2008.- Vol.586, №16.- Р. 4005-4010.
16. Normal blood flow velocities of basal cerebral arteries decrease with advancing age: a transcranial Doppler sonography study / S. Demirkaya, K. Uluc, S. Bek, [et al.] // Tohoku J. Exp. Med.- 2008.- Vol.214, №2.- Р. 145-149.
17. Дисфункция эндотелия и артериальная гипертензия / С.П.Власова, М.Ю.Ильченко, Е.Б.Казакова и др. / под ред. П.А. Лебедева.- Самара: Офорт, 2010.- 192 с.
18. Agabiti-Rosei E. Structural and functional changes of the microcirculation in hypertension: influence of pharmacological therapy / E.Agabiti-Rosei // Drugs.- 2003.- Vol.63, №1.- Р. 19-29.
19. Schiffrin E.L. Vascular changes in hypertension in response to drug treatment: Effects of angiotensin receptor blockers / E.L.Schiffrin // Can. J. Cardiol.- 2002.- Vol.18 (Suppl A).- Р. 15A-18A.
20. Верещагин Н.В. Патология головного мозга при атеросклерозе и артериальной гипертонии / Н.В.Верещагин, В.А.Моргунов, Т.С.Гулевская - М.: Медицина, 1997.- 288 стр.
21. Characteristics, practice patterns, and outcomes in patients with acute hypertension: European registry for Studying the Treatment of Acute hyperTension (Euro-STAT) / A.Vuylsteke, J.L.Vincent, D P. de La Garanderie [et al.] // Crit. Care.- 2011.- Vol. 15, № 6.- R271.
22. Grabowska-Gawel A. Usefulness of urapidil during intraoperative rise of arterial blood pressure in patients operated under general anesthesia / A.Grabowska-Gawel, K.Porzych, G.Grzesk // Przegl. Lek.- 2005.- Vol. 62, № 3.- Р. 148-151.
23. Запольская Е.А. Мониторинг мозгового кровотока и центральной гемодинамики при различных видах анестезии у пожилых больных с сопутствующей артериальной гипертензией: дис. ... кандидата мед. наук: 14.00.37 «Анестезиология и реаниматология» / Запольская Елена Александровна.- М.:2005.- 98 с.
24. Глубина анестезии и послеоперационные когнитивные дисфункции / О.А. Лоскутов, С.Н. Судакевич, А.Н. Дружина, и др. // Бшь, знеболювання i штенсивна тератя.- 2013.- №2д.- С.305-307.
