Monitoring of objective indicators of the condition of women in labor

Dynamics of cardiorespiratory system indicators

It is known that during pregnancy and childbirth, a functional restructuring of the cardiorespiratory system occurs, reflecting the increasing load on the respiratory and circulatory organs and is most pronounced in pregnant women whose pregnancy and childbirth occur against the background of obstetric and extragenital pathology.

Determination of the respiratory and circulatory system function indices should be performed under conditions as close as possible to the basal metabolic rate: in a semi-lateral position and not earlier than 6 hours after any drug therapy. It is recommended to examine women using gas analyzers. When assessing hemodynamics, it is advisable to use the indirect Fick principle with rebreathing. Central hemodynamics are assessed using the integral rheography method using a modified RG-1-01 device.

It is necessary to determine the respiratory rate (RR), minute respiratory volume (MRV), tidal volume (TV), predicted vital capacity (PVC), predicted minute respiratory volume (PMRV) according to Dembo-Antoni, the ratio of MRV to PMRV as a percentage, the amount by which MR exceeds PMRV, functional dead space (FDS) from the Bohr equation, minute alveolar ventilation (MAV), alveolar volume (AV), respiratory efficiency (RE), and ventilation efficiency (VE). It is necessary to evaluate the shape of the capnogram, the size of the alveolar plateau, the Van Meurton index, the angle of the capnogram, the rate of CO2 washout from the dead space, the ratio of inhalation/exhalation values, determining the point of the onset of the alveolar phase of expiration, measuring the fractional concentration of CO2 in exhaled air (FeCO2), in alveolar air (FAS02) and at the moment of cessation of diffusion during respiration. breathing (ФуС02). It is necessary to calculate the partial pressure of CO2 in the alveolar pelvis (РАС02), in arterial (РаС02) and venous (РУС02) blood.

The main factors determining blood circulation as a function and its efficiency are: circulating blood volume (CBV); cardiac output (minute volume of the heart - MOV); total peripheral resistance (TPR). The listed indicators undergo significant changes during pregnancy.

During a normal pregnancy, characteristic changes occur in the circulatory system. The increase in the pregnant woman's body weight, the increase in intra-abdominal pressure as the uterus grows, the higher position of the diaphragm and the associated change in the position of the heart, the formation of the uteroplacental ("third") circle of blood circulation require the circulatory system to undergo significant restructuring and adaptation to new operating conditions.

During pregnancy, there is an increase in the respiratory rate (RR) by 1/3, which is not decisive for ventilation. On the contrary, an increase in VR by 1/3 is decisive in the adaptation of the respiratory system during pregnancy. The presence of hyperventilation during pregnancy is associated with an increase in the MV, AO, and the MV/DMV ratio. Hyperventilation is mainly achieved by increasing VR and, to a lesser extent, RR. The necessary ventilation is ensured by an optimal combination of VR, RR, AO, and FMP. MAV increases by 70%. In pregnant women, the lower parts of the lungs are involved in breathing, where the ventilation-perfusion ratio improves. Hyperventilation and respiratory alkalosis are characteristic features during pregnancy.

Hemodynamics - a compensatory increase in heart rate develops, venous blood return decreases, and blood is deposited. A eukinetic type of blood circulation is created. Hyperventilation serves in these conditions to maintain the volumetric load on the left sections of the heart. In the hemodynamic system, the most informative indicator is the systolic arterial pressure on the right arm, reflecting cardiac output and increased tone of large arteries.

In women in labor after abdominal delivery, the indices of external respiration and blood circulation function on the 1st, 2nd and 3rd days remain hyperventilation with the minute volume of respiration exceeding by almost 1.5 times, respiratory alkalosis, hypocapnia with insufficient respiratory compensation of metabolic acidosis due to pronounced unevenness (breathing) of ventilation. Changes in hemodynamics in women in labor who delivered by cesarean section are aimed at forming a hypodynamic type of blood circulation with the minute volume of blood circulation exceeding by 1.5-2 times.

In physiological pregnancy, a twofold increase in the oxygen utilization coefficient is typical on the first day of the postoperative period. The value of the minute respiratory volume indicates significant hyperventilation (7-8 l/min), almost equal to its preoperative level. A hypodynamic type of blood circulation with an increase in the resistance load is noted (total peripheral resistance is 79% higher than during pregnancy).

On the 2nd day after cesarean section, stabilization of almost all indicators of the cardiorespiratory system occurs, with the exception of total peripheral vascular resistance, which significantly (by 58%) decreases compared to the 1st day of the postoperative period; the hypodynamic type of blood circulation is maintained.

On the 3rd day, signs of latent parenchymatous respiratory failure associated with deterioration of the ventilation-perfusion ratio are revealed; the hypodynamic type of blood circulation is maintained with an increase in systolic volume (by 43%) and an increase (by 35%) in total peripheral resistance compared to the 2nd day of the postoperative period.

Thus, cesarean section leads to weakening of the regulation of the cardiorespiratory system in women in labor in the early postoperative period. In most women with physiologically proceeding pregnancy, the hemodynamic regulation link is most susceptible to decompensation, in almost all women in labor with diabetes mellitus - the gas exchange link, in most women who have suffered late toxicosis of pregnancy, disturbances in both the blood circulation regulation link and the ventilation regulation link are likely.

These data are important for compliance with the principles of infusion-transfusion therapy aimed at correcting the functions of the cardiorespiratory system, when determining adequate volumes and composition of administered solutions, and their optimal ratios.

Monitoring water balance indicators

Water balance is the ratio between the amount of water entering the body and the amount excreted from it. Water balance is closely related to electrolyte balance. The average daily fluid intake is 2.5 liters, of which 1.2-1.5 liters comes from drinking, 0.8-1 liter from food. About 0.3 liters of water is formed in the body during oxidation processes. Under pathological conditions, water balance is sometimes seriously disturbed. This leads either to a state of dehydration (dehydration) of the body if the loss of fluid exceeds its intake, or, conversely, hyperhydration if more fluid is received than excreted.

For obstetric practice, it is important to consider the total amount of fluid that can be administered to a pregnant woman during labor. The total amount of fluid given to a woman in labor every hour, including dextrose (glucose) for infusion and oxytocin solution (if labor induction is planned), should average 75-150 ml/hour. Women with cardiac or renal disease should be given smaller amounts of fluid; it may be advisable to insert a central venous catheter for more careful monitoring of fluid intake.

Electrolytes. It is important to note that from both the physiological and clinical points of view, the exchange of water and sodium in the body are closely interrelated. During pregnancy, body weight increases partly due to the accumulation of fat (in the early stages of pregnancy), and mainly due to water. The total amount of water by the end of a normal pregnancy increases by 7.5 liters, which is not accompanied by edema. Much attention should be paid to the pathogenesis of water-salt metabolism disorders in some pregnancy complications (late toxicosis, etc.). During pregnancy, water retention in the body is combined with an increase in the sodium content, and thus a new level of osmotic pressure characteristic of pregnancy is maintained. During pregnancy, the mechanism is stimulated both in terms of increasing the excretion of sodium and its conservation. Changes in sodium metabolism during pregnancy are closely associated with hyperventilation. Thus, with late toxicosis of pregnancy, renal blood flow and glomerular filtration are reduced and water and sodium are retained. During a normal pregnancy, most of the water is outside the cells.

Potassium metabolism. Regulation of potassium balance is extremely important in maintaining homeostasis. Under normal conditions, a person consumes 60-100 mmol of potassium with food per day; of this amount, 5 to 10 mmol is excreted in feces, less than 5 mmol in sweating, and the rest in urine. The total potassium reserves in the body are approximately 40-45 mmol/kg of body weight. Of this amount, 90% of potassium is in the intracellular space and easily enters into exchange with 2% located in the extracellular fluid spaces; the remaining 8% of potassium is in bone tissue and does not participate in rapid metabolic processes. The normal concentration of potassium in the extracellular fluid ranges from 3.6 to 5 mmol/l. The intracellular concentration of this ion is from 140 to 160 mmol/l.

Hypercalcemia. Increased serum calcium concentration can be defined as an increase in serum calcium concentration above the upper limit of normal (recommended level). The upper limits of calcium concentration recommended by different laboratories vary slightly from each other, and the most commonly cited values are in the range of 8.5 to 10.5 mg% (2.15-2.60 mmol/L).

Calcium is present in the bloodstream in three forms: ionized, protein-bound, and complex. The complex fraction accounts for approximately 10% of the total calcium and is a compound of calcium with phosphate, bicarbonate, citrate, and other ions. The protein-bound fraction accounts for approximately 40%, with albumin being the main binding protein. The ionized fraction accounts for approximately 50% of the total calcium content in the blood serum. It is considered physiologically active, which is not only under the control of humoral mechanisms, but also affects the secretion of hormones.

[ 1 ], [ 2 ], [ 3 ], [ 4 ], [ 5 ]