General Obstetrics and Gynecology ObstetricsHemodynamic changes and baroreflex gain in the supine hypotensive syndrome☆
Section snippets
Subjects
Pregnant subjects were recruited from the Women and Infants Hospital obstetric clinic and associated ultrasound facilities. Entry criteria were fulfilled by response to a 10-question survey. The questionnaire identified two groups of subjects: women who had symptoms of supine hypotension (ie, dizziness, nausea, and anxiety in relation to supine positioning that is temporally related to the second and third trimesters) and women who had none of these symptoms. Potential candidates were
Results
Results of a comparison of demographic variables for SHS and non-SHS groups are presented in Table I, with no differences noted between the groups. Values are presented as mean ± SD.Group Age (y) Body mass index (kg/m2) Gestational age (wk) Hemoglobin (g/dL) Hematocrit (%) SHS (n = 10) 28 ± 6.9 31.7 ± 5.8 33.6 ± 3.7 11.9 ± 1.6 35.7 ± 4.1 Control (n = 10) 27 ± 7.3 33.2 ± 6.1 33.9 ± 4.1 11.5 ± 0.8 33.7 ± 1.7 P value .6 .56 .95 .62 .35
Comment
The sequence of events that precede symptoms of SHS is purported to be as follows: On supine positioning, there is a degree of compression of the inferior vena cava by the gravid uterus that produces a variable decrement in venous return. This, in turn, results in decreased stroke volume, which is sensed as decreased pressure in the aortic arch baroreceptors. Tachycardia develops in an attempt to restore cardiac output. However, with the persistence of caval compression, cardiac output is
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2019, Advances in AnesthesiaCitation Excerpt :Compression of the IVC results in reduced preload and increased maternal heart rate via the baroreceptor-mediated reflex. Symptoms commonly include maternal lightheadedness, dizziness, nausea, and general discomfort [13]. At the extreme, maternal and neonatal death have been attributed to supine hypotensive syndrome of pregnancy [14].
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2016, Legal MedicineCitation Excerpt :In the current case, the autopsy revealed that the abdominal viscera and diaphragm had been displaced superiorly by the ovarian tumor. In pregnant women, especially in the second and third trimesters, lying in the supine position can lead to the appearance of several symptoms associated with hypotension resulting from inferior vena cava compression by the gravid uterus [23]. This condition is known as supine hypotensive syndrome (SHS) and can lead to cerebral hypoperfusion and hypoxia.
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2016, Anesthesiology ClinicsCitation Excerpt :There is an increased risk of desaturation during periods of apnea (such as induction), increased risk of aspiration (second and third trimesters), increased risk of difficult intubation, decreased MAC, yet increased risk of awareness.2–4 In addition, the gravid uterus (second and third trimesters) can cause maternal hypotension in the supine position from compression of the aorta and inferior vena cava.5 A 2012 review of complications after nonobstetric surgeries in pregnant women from the National Surgery Quality Improvement Program (NSQIP) data showed that 30-day mortality was very low (0.25%).6
Maternal Physiology
2016, Obstetrics: Normal and Problem PregnanciesPrevention of supine hypotensive syndrome in pregnant women treated with transcranial magnetic stimulation
2014, Psychiatry ResearchCitation Excerpt :Supine hypotensive syndrome (also referred to as inferior vena cava compression syndrome) is caused when the gravid uterus compresses the inferior vena cava when a pregnant woman is in a supine position, leading to decreased venous return centrally. Up to 8% of women in the second and third trimesters of pregnancy can be affected (Lanni et al., 2002). Symptoms usually occur within 3–10 min after lying down (Kinsella and Lohmann, 1994).
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