RU2487663C1 - Method of estimating metabolic and cardiorespiratory adaptation of cardiosurgical patients - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention relates to medicine, namely to anesthesiology and intensive therapy and can be used in case of necessity to estimate degree of patient's metabolic and cardiorespiratory adaptation. For this purpose during operation and intensive therapy successive inhalation of gas mixture with 51% (FiO₂=0.51) and 21% (FiO₂= 0.21) content of oxygen is carried out. After that, consumption of oxygen and release of carbon dioxide at each stage are determined, and power of anaerobic threshold by FiO₂ in gas mixture, corresponding to the moment of anaerobic threshold achievement, is calculated. If power of anaerobic threshold is >0.14, degree of patient's metabolic and cardiorespiratory adaptation is considered to be low. If index value is <0.1, degree of patient's metabolic and cardiorespiratory adaptation is considered to be high. If index value is 0.1-0.14, degree of patient's metabolic and cardiorespiratory adaptation is considered to be medium.

EFFECT: method makes it possible to ensure reduction of probability of development of hypoxic complications in critical patients due to determination of degree of metabolic and cardiorespiratory adaptation during operation and intensive therapy, including mode of monitoring.

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Description

The invention relates to medicine, namely to methods for determining the degree of metabolic and cardiorespiratory adaptation of patients by the power of the anaerobic threshold, which is an important characteristic of the characteristics of the interaction of metabolic reactions of the body, as well as the functional state of the human cardiorespiratory system. The anaerobic threshold (AP) reflects subtle changes in cellular metabolism, is a sensitive indicator of circulating and metabolic adaptation and has significant prognostic value [1]. AP reflects the current state of a person and depends on the degree of his physical and (or) mental fatigue, therefore, it is most relevant for monitoring the current somatic status of a person.

There is a method for determining the degree of metabolic and cardiorespiratory adaptation of a patient by the power of the anaerobic threshold, including inhaling during ergospirometry of a hypoxic gas mixture with a stepwise decrease in oxygen content by 2% at each stage until stabilization of oxygen consumption and carbon dioxide emissions are achieved at each stage. The anaerobic threshold is determined at the moment of intersection of the curves of oxygen consumption and carbon dioxide emission. An indicator characterizing the degree of metabolic and cardiorespiratory adaptation of the patient - the power of the anaerobic threshold (MAP) - is the percentage of oxygen in the inhaled hypoxic gas mixture corresponding to the moment the anaerobic threshold is reached. With a value of the indicator> 14%, the power of the anaerobic threshold (respectively, the degree of metabolic and cardiorespiratory adaptation of the patient) is considered low, with a value of <10%, the power of the anaerobic threshold is considered high, with a value of 10% -14%, the power of the anaerobic threshold is considered average [2] .

This method is the closest to the claimed technical essence and the achieved result and is selected as a prototype.

The disadvantage of this method is that it requires the use of complex expensive equipment (ergospirometer, a device for preparing a hypoxic gas mixture) and due to the complexity does not allow the determination of the anaerobic threshold in monitoring mode in patients during surgery and intensive care. In addition, breathing a gas mixture with an oxygen content below atmospheric, as necessary according to the conditions of the prototype method, may be accompanied by violations of oxygen homeostasis in critically ill patients and requires increased safety measures.

The objective of the invention is to increase the safety of the method, allowing to determine the degree of metabolic and cardiorespiratory adaptation of the patient during surgery and intensive care in monitoring mode.

The problem is achieved by a technical solution, which is a way of assessing the degree of metabolic and cardiorespiratory adaptation of cardiosurgical patients by the power of the anaerobic threshold, including sequential inhalation of the gas mixture with 51% (FiO ₂ = 0.51) and 21% (FiO ₂ = 0.21) content oxygen. At the same time, it is necessary that the parameters of mechanical ventilation, indicators of homeostasis, therapeutic measures throughout all measurements remain unchanged. At the stage of inhalation of a gas mixture with 51% oxygen content, the percentage of oxygen and the partial tension of carbon dioxide in the exhaled volume are measured using the gas module of the Primus anesthesia apparatus (Dräger). After stabilization of the indicators (usually after 3-5 minutes), their values are fixed and oxygen consumption and carbon dioxide emission are determined.

After completing the measurements, they begin to inhale the gas mixture with 21% oxygen and, using the gas module of the Primus anesthesia apparatus (Dräger), measure the percentage of oxygen and the partial voltage of carbon dioxide in the expired volume. After stabilization of the indicators (usually after 3-5 minutes), their values are fixed and oxygen consumption and carbon dioxide emission are determined. The carbon dioxide emission at the measurement stages does not change when using our method.

Since the anaerobic threshold is determined at the moment of intersection of the curves of oxygen consumption and carbon dioxide emission, the anaerobic threshold is considered to be achieved when the oxygen consumption at the time of reaching the AP is equal to the carbon dioxide emission value.

The MAP index, expressed as FiO ₂ in the inhaled gas mixture, corresponding to the moment of reaching the anaerobic threshold, is considered a characteristic of the degree of metabolic and cardiorespiratory adaptation of the patient, i.e. the power of the anaerobic threshold in a particular patient. When the value of the MAP index> 0.14 is considered the power of the anaerobic threshold (respectively, the degree of metabolic and cardiorespiratory adaptation of the patient) is low, when the value of the indicator <0.1, the power of the anaerobic threshold is considered high, when the value of the indicator is 0.1-0.14, the power of the anaerobic middle threshold.

New in the proposed method is the sequential inhalation during surgery and intensive care of a gas mixture with 51% (FiO ₂ = 0.51) and 21% (FiO ₂ = 0.21) oxygen content, determination of oxygen consumption and carbon dioxide emission at each stage and calculating the power of the anaerobic threshold according to known formulas, as well as the values of the power of the anaerobic threshold of patients corresponding to various degrees of adaptation of patients.

New signs make it possible to determine the power of the anaerobic threshold in patients during surgery and intensive care in the monitoring mode and to avoid hypoxic complications in critical patients by eliminating the decrease in oxygen content in the respiratory mixture of the mixture below atmospheric (21%).

Distinctive features showed in the inventive combination of new properties that are not explicitly derived from the prior art in this field and are not obvious to a specialist. No identical set of features was found in the analyzed literature. The proposed technical solution can be used in healthcare.

Based on the foregoing, this technical solution should be considered relevant to the conditions of patentability: "novelty", "inventive step", "industrial applicability".

The invention will be clear from the following description and the attached figure 1.

Figure 1 shows a graph for calculating the power of the anaerobic threshold. The values of PO _2-0.51 (point 1) and VCO _2-0.51 (point 3) found in measurements 1 (with FiO ₂ = 0.51) are _postponed . The values of PO _2-0.21 (point 2) and VCO _2-0.21 (point 4) found in measurements 2 (with FiO ₂ = 0.21). Connect points 1 and 2 with a straight line and extend it to the intersection with the VCO ₂ line constructed in the same way and extended (connected points 3 and 4). The intersection point of the extended lines corresponds to the MAP (point 5), the value of which is calculated by the formula.

The method is as follows:

Determination of the power of the anaerobic threshold during surgery and intensive care is carried out on the background of mechanical ventilation using an anesthesia-respiratory apparatus Primus (Dräger). The procedure begins with the patient giving a respiratory gas mixture with 51% (FiO ₂ = 0.51) oxygen content. Using the gas module of the Primus anesthesia apparatus (Dräger), after stabilization of the indicators (usually after 3-5 minutes), the percentage of oxygen and the partial tension of carbon dioxide in the exhaled volume are measured, their values are recorded and oxygen consumption and carbon dioxide emission are determined by the formulas.

PO _2-0.51 = (51-O _{2 vyd.-0.51} ) × MOD, where

PO _2-0.51 - (ml / min) oxygen consumption by inhalation of the gas mixture with FiO ₂ = 0.51;

51 - (%) the percentage of oxygen on inspiration when inhaling a gas mixture with FiO ₂ = 0.51;

O _{2 vyd. -0.51} - (%) the percentage of oxygen on the exhale when inhaling a gas mixture with FiO ₂ = 0,51;

MOD - (ml / min) minute volume of respiration.

VCO _2-0.51 = etCO _2-0.51 × MOD: BP, where

VCO _2-0.51 - (ml / min) evolution of CO ₂ by inhalation of the gas mixture with FiO ₂ = 0.51;

etCO _2-0.51 (mmHg) partial tension of CO ₂ at the end of exhalation (end tidal) when the gas mixture is inhaled with FiO ₂ = 0.51;

MOD - (ml / min) minute volume of respiration;

BP - (mmHg) atmospheric pressure (barometric pressure).

After that, the patient is given a respiratory gas mixture with 21% (FiO ₂ = 0.21) oxygen content (atmospheric air). After stabilization of the indicators, the measurement is repeated and the oxygen consumption and carbon dioxide emission are determined by the above formulas. At the same time, they are convinced that the parameters of mechanical ventilation, indicators of homeostasis, therapeutic measures throughout all measurements remained unchanged.

PO _2-0.21 = (21-O _{2 vyd.-0.21} ) × MOD, where

PO _2-0.21 - (ml / min) oxygen consumption by inhalation of the gas mixture with FiO ₂ = 0.21;

21 - (%) the percentage of oxygen on inspiration when inhaling a gas mixture with FiO ₂ = 0.21;

O _{2 vyd.-0.21} - (%) the percentage of oxygen on the exhale when inhaling a gas mixture with FiO ₂ = 0.21;

MOD - (ml / min) minute volume of respiration.

VCO _2-0.21 = etCO _2-0.21 × MOD: BP, where

VCO ₂ - (ml / min) emission of CO ₂ by inhalation of a gas mixture with FiO ₂ = 0.21;

etCO _2-0.21 (mmHg) partial tension of CO ₂ at the end of exhalation (end tidal) when the gas mixture is inhaled with FiO ₂ = 0.21;

MOD - (ml / min) minute volume of respiration;

BP - (mmHg) atmospheric pressure (barometric pressure).

All obtained values of oxygen consumption and carbon dioxide emissions are substituted into the formula for determining the power of the anaerobic threshold.

MAP = 0.21- (PO _2-0.21 -VCO ₂ ) × 0.3: (PO _2-0.51 -PO _2-0.21 ), where

MAP - (FiO ₂ ) anaerobic threshold power;

0.21 - FiO ₂ in atmospheric air;

PO _2-0.21 - (ml / min) oxygen consumption by inhalation of air with FiO ₂ = 0.21;

VCO ₂ - (ml / min) emission of CO ₂ ;

0.3-ΔFiO ₂ = 0.51-0.21;

PO _2-0.51 - (ml / min) oxygen consumption by inhalation of the gas mixture with FiO ₂ = 0.51.

When the value of the MAP indicator> 0.14 is considered the power of the anaerobic threshold (respectively, the degree of metabolic and cardiorespiratory adaptation of the patient) is low, when the value of the indicator <0.1, the power of the anaerobic threshold is considered high, when the value of the indicator is 0.1-0.14, the power of the anaerobic middle threshold.

Example 1. Patient M., 52 g. No. 1056. Height 175 cm, weight 83 kg.

Main disease: coronary heart disease, FC III. Aneurysm of the left ventricle.

Concomitant disease: Chronic gastritis in remission. Duodenitis.

During the CABG + RALZH operation, after intubation, before incision, the MAP was determined by the method, which consistently inhaled the gas mixture with 51% (FiO ₂ = 0.51) and 21% (FiO ₂ = 0.21) oxygen content. At the stage of inhalation of a gas mixture with 51% oxygen content, the percentage of oxygen and the partial tension of carbon dioxide in the exhaled volume were measured using the gas module of the Primus anesthesia apparatus (Dräger). After stabilization of the indicators after 5 minutes, their values were recorded and oxygen consumption was determined by the formulas. After completing the measurements, they started to inhale the gas mixture with 21% oxygen and using the gas module of the Primus (Dräger) anesthesia-respiratory apparatus measured the percentage of oxygen and the partial tension of carbon dioxide in the exhaled volume. After stabilization of the indicators, after 5 minutes, their values were recorded and oxygen consumption and carbon dioxide emission were determined according to the above formulas. MAP was calculated, which in this patient was 0.16. Therefore, the power of the anaerobic threshold (respectively, the degree of metabolic and cardiorespiratory adaptation) in this patient is low.

A coronary artery bypass grafting and resection of the left ventricular aneurysm were performed under cardiopulmonary bypass. The duration of the operation was 6 hours 10 minutes, the duration of the IR was 3 hours 17 minutes.

In the early postoperative period, 2 hours after the operation, symptoms of heart weakness occurred, dopmin infusion was started at a rate of 5 μg / kg / min. According to the above method, the determination of MAP was performed, which amounted to 0.17. The dopmin rate was added up to 8 μg / kg / min and MAP was determined, the result was 0.15, therefore, the degree of metabolic and cardiorespiratory adaptation at this dose of dopmin improved. The duration of mechanical ventilation after surgery was 48 hours. There were signs of heart and respiratory failure, the duration of inotropic support was 96 hours.

After 6 days, the patient was transferred to a general ward.

Example 2. Patient D., 63 g. No. 927. Height 170 cm, weight 87 kg.

Main disease: coronary heart disease, FC III.

Concomitant disease: Type 2 diabetes. Chronic cholecystitis, stage of remission.

During CABG surgery, after intubation, prior to incision, the MAP was determined by the method, which consistently inhaled the gas mixture with 51% (FiO ₂ = 0.51) and 21% (FiO ₂ = 0.21) oxygen content. At the stage of inhalation of a gas mixture with 51% oxygen content, the percentage of oxygen and the partial tension of carbon dioxide in the exhaled volume were measured using the gas module of the Primus anesthesia apparatus (Dräger). After the indicators stabilized, their values were recorded after 4 minutes and the oxygen consumption was determined by the formula 1. After the measurements were completed, we inhaled the gas mixture with 21% oxygen and measured the percentage of oxygen and the partial voltage using the gas module of the anesthesia-respiratory apparatus Primus (Dräger) carbon dioxide in expired volume. After stabilization of the indicators after 3 minutes, their values were recorded and oxygen consumption and carbon dioxide emission were determined using the above formulas. MAP was calculated, which in this patient was 0.14. Therefore, the power of the anaerobic threshold (respectively, the degree of metabolic and cardiorespiratory adaptation) in this patient is average.

A coronary artery bypass grafting was performed under cardiopulmonary bypass. The duration of the operation was 5 hours 20 minutes, the duration of the IR was 1 hour 45 minutes.

4 hours after surgery, the patient developed an AV block with a heart rate of 52 beats / min. An ECS was imposed in VVI mode using epicardial electrodes with a frequency of 70 beats / min. After that, we determined the power of the anaerobic threshold according to the method described above. MAP was 0.14. Then the stimulation frequency was added up to 80 bpm and the MAP was again determined, which amounted to 0.13, that is, the degree of metabolic and cardiorespiratory adaptation increased. The stimulation mode was set at a frequency of 80 beats / min. On the 2nd day after the operation, its own sinus rhythm was restored with a sufficient frequency, the EX was disabled. The duration of mechanical ventilation after surgery was 9 hours.

After 3 days, the patient was transferred to the general ward.

Example 3. Patient P., 57 l. I.b. No. 1028. Height 182 cm, weight 90 kg.

Main disease: coronary heart disease, FC III.

Concomitant disease: Osteochondrosis of the lumbar spine.

During CABG surgery, after intubation, before the incision, MAP was determined against the background of mechanical ventilation using the Primus anesthesia-breathing apparatus (Dräger). The procedure was started by giving the patient a respiratory gas mixture with 51% (FiO ₂ = 0.51) oxygen content. Using the gas module of the Primus anesthesia apparatus (Dräger), after stabilization of the indicators, after 5 minutes, the percentage of oxygen and the partial voltage of carbon dioxide in the exhaled volume were measured, their values were recorded and oxygen consumption and carbon dioxide emission were determined using the above formulas.

After that, the patient was given a respiratory gas mixture with 21% (FiO ₂ = 0.21) oxygen content (atmospheric air). After stabilization of the indicators, the measurement was repeated and the oxygen consumption and carbon dioxide emission were determined by the formulas. At the same time, they were convinced that the parameters of mechanical ventilation, indicators of homeostasis, therapeutic measures throughout all measurements remained unchanged.

The power of the anaerobic threshold in this patient was 0.11, which corresponds to an average degree of metabolic and cardiorespiratory adaptation.

A coronary artery bypass grafting was performed under cardiopulmonary bypass. The duration of the operation was 4 hours 30 minutes, the duration of the IR was 1 hour 20 minutes.

3 hours after the operation, the MAP was re-determined according to the method described above. The power of the anaerobic threshold was 0.12 and was rated as average.

The duration of mechanical ventilation after surgery was 6 hours, inotropic support was not required. No complications were observed.

On the third day, the patient was transferred to a general ward.

The method proposed by the authors was tested in 35 patients, it allows to determine the degree of metabolic and cardiorespiratory adaptation of cardiosurgical patients in the monitoring mode, increases the safety of the method.

Bibliography

1) The physiological significance of the "anaerobic threshold" / K.Wasserman, G.G. Burton, A.C. Van Kessel // Physiologist. - 1964. - V.7. - P.279-284.

2) RF patent No. 2432114. Publ. October 27, 2011 Bull. No. 30. A method for assessing the degree of metabolic and cardiorespiratory adaptation of a patient. Authors Yu.K. Podoksenov, T.V. Emelyanova, V.M. Shipulin, Yu.S. Svirko, O.G. Kiyko, O.O. Panteleev, Z.N. Zhikhareva, A.S. Gorokhov, A .Yu. Podoksenov, D.A. Prut.

Claims (1)

A method for assessing the degree of metabolic and cardiorespiratory adaptation of cardiosurgical patients, which consists in determining the anaerobic threshold at the time of achieving equality of oxygen consumption and carbon dioxide emission and measuring the power of the anaerobic threshold, characterized in that during the operation and intensive care, the gas mixture is sequentially inhaled with 51% ( FiO ₂ = 0.51) and 21% (FiO ₂ = 0.21) with oxygen content, determine the oxygen consumption and carbon dioxide emission at each stage and calculate the power a the FIO ₂ aerobic threshold in the gas mixture corresponding to the moment of reaching the anaerobic threshold, and when the anaerobic threshold power is> 0.14, the patient’s metabolic and cardiorespiratory adaptation is considered low, with a value of <0.1, the patient’s metabolic and cardiorespiratory adaptation is high, with a value of 0.1-0.14, consider the degree of metabolic and cardiorespiratory adaptation of the patient as average.