Peculiarities of pneumonia in pregnancy

One of the priorities in the development of national health is the provision of safe motherhood and childhood. This issue is extremely relevant due to the decrease in the population of healthy parturient women, which leads to an increase in perinatal pathology.

The formation of pathology in the perinatal period in 99.5% of cases is associated with conditions arising during pregnancy, during childbirth and appearing at the time of childbirth, and only in 0.5% of cases it occurs during the first week of life.

To date, it has been proven that virtually all pre-pregnancy chronic diseases lead to systemic changes in hemodynamics and microcirculation in the formation of the fetoplacental circulatory cycle, resulting in the development of fetoplacental insufficiency (FPN). Fetoplacental insufficiency is a clinical syndrome that is caused by morphological and functional changes in the placenta against the background of disorders of the state of the maternal organism and is manifested by fetal hypoxia and a violation of its growth and development. The most common cause of fetoplacental insufficiency is the mother's extragenital pathology.

Extragenital pathology is a large group of diseases or conditions that affect to a varying degree the rates of maternal and perinatal mortality, the frequency of complications of pregnancy, childbirth and the postpartum period, perinatal morbidity.

In the structure of the causes of maternal mortality in Ukraine in 2007, extragenital pathology was 27.7%; bleeding - 25.3%; preeclampsia / eclampsia - 14.4%; embolism with amniotic fluid - 10.9%; thromboembolism of the pulmonary artery - 12.1%; sepsis - 4.8%; other reasons - 4.8%. As can be seen from the data given, almost one third of women die from extragenital pathology.

Among the causes of maternal deaths from extragenital pathology, infection takes the first place - 36.3%; further - diseases of the circulatory system - 31.8%, digestive organs - 13.6%; malignant neoplasms - 13,6%.

Mortality of pregnant and maternity patients from lung diseases (mainly from pneumonia) ranks third (13%) after cardiovascular diseases (28.5%) and acute viral hepatitis (18.6%). Among the causes of death from infectious diseases pneumonia is in the first place.

The wide prevalence of extragenital pathology and the variety of nosological forms complicating the course of pregnancy necessitated the mandatory inclusion of a new link - a therapist or a specialist - in the classical chain of interaction "obstetrician-gynecologist-pregnant". This interaction helps to provide mother and child care at a qualitatively new level by choosing a strategy for treating extragenital pathology, taking into account the physiological changes in the female body, developing tactics of management, optimal timing and methods of delivery, with maximum safety for the life of the mother and child.

One of the topical areas of such interdisciplinary interaction is the management of pregnancy against the background of the pathology of the respiratory system. In a situation where "the mother breathes for two", pneumonia is the particular danger as the most common cause of the development of acute respiratory failure (DV) in pregnancy.

The prevalence of out-of-hospital pneumonia in pregnant women ranges from 1.1 to 2.7 per 1000 births, which does not exceed the rates among non-pregnant women aged 20 to 40 years. The development of pneumonia on the background of pregnancy increases the risk of complications from the mother and fetus, while the mortality rates are comparable with those in the general population.

The situation changes when it comes to periods of the epidemic of influenza A. The experience of the largest epidemics of influenza in the XX century. Showed that the highest morbidity and mortality in the epidemic period is typical for pregnant women. Clinical manifestations of acute respiratory viral infection (ARI) and influenza in pregnant women do not differ from those in age-comparable populations of non-pregnant women, but by the third trimester the risk of hospitalization even in women without risk factors increases.

According to the California Department of Public Health in April-August 2009 (the period of the flu epidemic "California" H1N1), 10% of 1,088 hospitalized were pregnant, 57% of them in the third trimester.

The development of influenza A on the background of pregnancy has always increased the risk of complications such as premature birth, acute respiratory distress syndrome, increased rates of maternal and infant mortality.

Pregnant women make up only 1-2% of the total population, and among patients hospitalized during the H1N1 influenza pandemic, 7 to 10%. According to the FDA for the period from April 14 to August 21, 2009 of all patients with confirmed influenza H1N15% were pregnant.

It is important to emphasize the fact that pregnancy as a physiological state of the female body is not a risk factor for the development of pneumonia, but is associated with a large number of complications of the disease. In order to understand the features of the course of pneumonia in this group of patients, it is necessary to consider in more detail a number of physiological changes in their respiratory system, gas exchange and immunity.

Physiological features of the respiratory system during pregnancy. Changes in the respiratory system begin with the first week of pregnancy. Due to the secretion of progesterone, there is a change in respiratory volumes, and sometimes the frequency of respiratory movements. Similar phenomena can be observed in non-pregnant women in the luteal phase of the cycle or in the appointment of progesterone.

Due to the pregnant uterus, the diaphragm rises by 4 cm, while its tour does not change. The functional residual capacity of the lungs is reduced by 20%. The maximum ventilation of the lungs increases throughout pregnancy and by the time of delivery it increases by 20-40%, the alveolar ventilation increases by 50-70% to compensate for respiratory alkalosis, which develops under the influence of progesterone.

Gas composition of blood. During pregnancy, oxygen consumption increases by 33%.

Physiological hyperventilation leads to the development of respiratory alkalosis - Ra CO2 = 28-32 mm Hg. While Pa O2 should be maintained at 105 mm Hg. Art. Minor changes in the blood gas composition of the mother lead to significant changes in the oxygenation of the fetus. The body's need for oxygen during pregnancy increases by 15-20%, while the reserve lung volume decreases. Thus, increased oxygen consumption and a decrease in the compensatory capacity of the respiratory system are factors predisposing to the development of severe DV. The risk of transfer to artificial ventilation of the lungs with the development of pneumonia in patients of this group is increased by 10-20%. The development of severe hypoxia against pneumonia is the third most common indication for intubation among all obstetric patients.

Immunity. Against the background of pregnancy, the cytotoxic activity of lymphocytes decreases, the amount of T-helper decreases and the activity of NK-killer decreases, which increases the susceptibility to viral and fungal infections. For pregnant women with the presence of foci of acute and chronic infection, the suppression of the cellular and the lack of an adequate response from the side of humoral immunity is characteristic. Pregnancy increases the risk of complications of influenza by 50%.

Increased incidence of influenza among pregnant women is associated not only with physiological and immunological changes in the mother's body, but also with the constantly changing antigenic structure of the virus.

The H1N1 influenza pandemic showed that patients in the third trimester of pregnancy and women in the early postpartum period are most susceptible to this virus. According to the California Pandemic (H1N1) Working Group, 22% of the total number of patients (102 women) were in need of admission to the intensive care unit (ICU) and respiratory support. Mortality among pregnant women following the 2009 pandemic was 4.3 maternal deaths per 100,000 live births.

Among the risk factors for the development of pneumonia, not related to the physiology of pregnancy, the most significant are HIV, cystic fibrosis, anemia, steroids, including obstetric evidence, bronchial asthma (detected in 16% of pregnant women hospitalized for pneumonia during the California H1N1 flu epidemic) , and the third trimester of pregnancy (according to various studies from 50 to 80% of cases of pneumonia occur during this period).

As a consequence of respiratory failure, the most serious complications of pneumonia are acute fetal distress, antenatal fetal death, premature births with the birth of children with low body weight (less than 2500 g in 36% of cases).

In newborns from mothers with pneumonia on the background of H1N1 influenza, intrauterine pneumonia, cerebral ischemia, intraventricular hemorrhages, convulsive and vegetative-visceral syndrome, transient myocardial dysfunction developed more often. Complications arising on the background of this pathology lead to an increase in infant mortality rates; depending on the studies it is from 1.9 to 12% o.

The purpose of this study was to determine the features of pneumonia in pregnancy and the effectiveness of the PSI, CURB-65 and Coopland scales in assessing the condition of pregnant women, to identify groups and risk factors for developing severe DV, to develop an algorithm for managing patients with symptoms of acute respiratory viral infection from the position of general practitioner.

25 case histories of pregnant women who have been through intensive care and / or pregnancy pathology (OST) for the period from October 2009 to March 2011 were selected. Patients were divided into 2 groups: those who passed through the ICU (n = 18) were the first group and the second group treated in the OPB (n = 7). The average age of pregnant women in the first group was 29 ± 3,3 years, in the second group - 23 ± 6,7 years.

Analysis of the data showed that 88% of patients at the time of the disease were in the third trimester of pregnancy. As in the first, and in the second group, women with extragenital pathology predominated - 67% and 72%, respectively. All patients who underwent ICU treatment were hospitalized during the 2009-2010 epidemics of influenza, only in 3 virologically confirmed influenza A H1N1.

According to the order of the Ministry of Health of Ukraine dated March 19, 2007 № 128 "About solidification of clinical protocols, medical facilities for specialty" Pulmonology "" PSI and CURB-65 scales are used to assess the severity of the patient's condition with pneumonia and determine the level of medical care.

A retrospective assessment of the condition of pregnant women at the time of admission to the ICU or OPB showed that according to the CURB-65 scale, 50% of the patients hospitalized in the ICU were subject to outpatient treatment, 48.2% were hospitalized and only 1.8% met the criteria for treatment in the ICU. 100% of patients of the second group in CURB-65 scored 0 points, ie they were subject to outpatient treatment.

A similar picture was obtained using the PSI scale. Of the 18 patients hospitalized in the ICU, 16 received no more than 70 points (I and II risk groups) - an indication for outpatient treatment, 1 patient was assigned to group III (inpatient treatment) and 1 to IV (treatment in the ICU). All pregnant women treated with OPB were classified as a risk group according to the PSI scale.

According to the order of the Ministry of Health of Ukraine from 28.12.2002 № 503 "About the procurement of ambulatory acupuncture-gynecological assistance in Ukraine" pregnant women were assessed according to the Coopland scale to determine the level of medical care. All patients belonged to groups of high or very high risk of perinatal or maternal pathology. In the first group, the majority (62%) of pregnant women were in very high risk groups, in the second group this category of patients was 42%.

Pregnant women who passed through the ICU were divided into 2 groups: patients whose first application for medical care coincided with the date of hospitalization in the ICU (n = 12); Patients who have been admitted to specialized hospitals (FBS, obstetrical department of CRH) (n = 7).

Features of the group of pregnant women, initially hospitalized in the ICU:

• 84% of women were between the ages of 30 and 40;
• According to the Coopland scale, 4 patients were high and 8 were very high risk (7 to 17 points);
• in four patients with the lowest in the group points on the scale of Coopland (5-6 points) recorded the latest application for medical care - on the 3-4th day after the onset of the disease;
• 50% of patients in the very high-risk group in Coopland are hospitalized in the ICU 24-48 hours after the onset of the disease, indicating that this group of pregnant women is predisposed to develop acute DV;
• in the structure of extragenital pathology in the whole group of patients, initially hospitalized in the ICU, chronic pyelonephritis, bacterial vaginosis, anemia I-II st.

The main indication for hospitalization in the ICU was a decrease in Sat O2 to 95%. The analysis of the gas composition of venous blood showed that even with Sat O2 within 90-95%, the partial pressure of O2 of venous blood (Pv O2) is significantly reduced. For example, with Sat O2 equal to 94%, Pv O2 is 26 mm Hg. Art. At a rate of 37-42 mm Hg. St, which indicates the presence of "latent hypoxia", which is associated with the features of the hemoglobin dissociation curve.

Oxygenation is characterized by two factors: oxygen saturation of hemoglobin and oxygen tension in the blood. These parameters are among themselves in a relationship determined by the shape and position of the hemoglobin dissociation curve (Figure). The steep portion of the curve indicates the possibility of oxygen binding by hemoglobin in the lungs and its return to tissues with small changes in the partial pressure of oxygen (Pv O2). A flat section of the curve indicates a decrease in the affinity of hemoglobin for oxygen in the region of high values of Pv O2.

Moderate hypoxemia is characterized primarily by a decrease in Pv O2, while oxygen saturation with blood changes little. Thus, with a decrease in Pv O2 from 90 to 70 mm Hg. Art. Saturation decreases by only 2-3%. This explains the so-called "latent" or "latent" hypoxia, singled out by some authors, when hypoxemia, judging by the saturation of the blood with oxygen, is not detected in severe violations of pulmonary respiration.

These data suggest that the use of pulsoximetry alone to determine the degree of hypoxia, especially in patients with extragenital pathology, may lead to an underestimation of the severity of the condition of the pregnant woman. Therefore, in the plan of examination of patients with respiratory pathology in the context of pregnancy with a saturation value of less than 95%, it is necessary to include an analysis of the gas composition of the blood.

Thus, the risk factors for the development of severe pneumonia, especially during the epidemic of influenza, include: III trimester of pregnancy; age from 30 to 40 years; presence of extragenital pathology, especially anemia and foci of chronic infection (chronic pyelonephritis, bacterial vaginosis); high and very high risk on the Coopland scale; later seeking medical help, leading to a deterioration in the prognosis of the course of the disease, even in patients without extragenital pathology.

Given these facts, women in the second and third trimester of pregnancy should be vaccinated against influenza, and also pulse oximetry to all patients with pneumonia at each stage of medical care with subsequent determination of blood gas composition in conditions of ICU. Treatment of pneumonia in pregnant women, regardless of the gestational age and the presence or absence of extragenital pathology, requires dynamic follow-up by both the obstetrician and gynecologist and the therapist. Therefore, the optimal treatment regimen for this category of patients is stationary.

Prof. TA Pertseva, Assoc. TV Kireeva, NK Kravchenko. Peculiarities of pneumonia during pregnancy // International Medical Journal №4 2012

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