Is crystalloid co-loading necessary to prevent spinal hypotension during elective cesarean delivery? A randomized double-blind trial.

BACKGROUND: Hypotension is common during spinal anesthesia for cesarean delivery. Preventive strategies include fluid loading and phenylephrine. We hypothesized that if prophylactic phenylephrine infusion is used, omission of fluid loading would be non-inferior to fluid co-loading in maintaining cardiac output. We assumed that if there was a difference, the increase in cardiac output would be greater in the no-loading than in the co-loading group. METHODS: Term pregnant women scheduled for elective cesarean delivery were randomized to receive 1 L crystalloid co-loading or maintenance fluids only. Phenylephrine was titrated to maintain blood pressure. Changes in cardiac output following spinal anesthesia were the primary outcome. The study was powered as a non-inferiority trial, allowing the no-loading arm to have a 50% greater change in cardiac output. Heart rate, dose of phenylephrine, occurrence of nausea and vomiting, Apgar scores and neonatal acid base status were secondary outcomes. RESULTS: Data from 63 women were analyzed. In contrast to our hypothesis, there was 33% less increase in cardiac output with no loading (ratio 0.67, 95% CI 0.15 to 1.36), and 60% greater reduction of cardiac output with no loading (ratio 1.6, 95% CI 1.0 to 2.7). Total dose of phenylephrine was higher in the no-loading group. There may be a less favorable neonatal acid base status without volume loading. CONCLUSION: Omission of crystalloid co-loading leads to a decrease in cardiac output which has a potentially unfavorable impact on neonatal acid base status. We conclude that crystalloid co-loading may be useful in the presence of phenylephrine infusion.

Impact of gestational diabetes mellitus on maternal cardiac adaptation to pregnancy.

OBJECTIVE: To determine whether maternal cardiac adaptation at term differs between women with, and those without, gestational diabetes mellitus (GDM). METHODS: This was a prospective case-control study of pregnant women at term with or without GDM. For both cases and controls, only women without any comorbidity or form of pre-existing diabetes who had a singleton pregnancy without complication (such as pre-eclampsia or fetal growth restriction) were included. All women underwent conventional and speckle-tracking echocardiography to assess both the left- and right-heart geometry and function. RESULTS: A total of 40 women with GDM and 40 healthy controls were enrolled. Women with GDM, compared with controls, had a significantly higher heart rate (83 ± 10 vs 75 ± 9 beats per min; P < 0.001), left ventricular (LV) relative wall thickness (0.43 ± 0.07 vs 0.37 ± 0.08; P < 0.001), LV early diastolic transmitral valve velocity (E) (0.80 ± 0.15 vs 0.73 ± 0.12 m/s; P = 0.026) and LV late diastolic transmitral valve velocity (A) (0.65 ± 0.13 vs 0.57 ± 0.11 m/s; P = 0.006). In women with GDM compared with controls, speckle-tracking analysis revealed a significant reduction in LV global longitudinal strain (GLS) (-16.29 ± 2.26 vs -17.61 ± 1.89; P = 0.012), LV endocardial GLS (-18.50 ± 2.59 vs -19.84 ± 2.35; P = 0.031) and LV epicardial GLS (-14.40 ± 2.01 vs -15.73 ± 1.66; P = 0.005). Right ventricular (RV) analysis revealed a reduced pulmonary acceleration time (58 ± 10 vs 66 ± 11 ms; P = 0.001) and RV E/A ratio (1.13 ± 0.18 vs 1.29 ± 0.35; P = 0.017), as well as a higher RV myocardial systolic annular velocity (0.16 ± 0.04 vs 0.14 ± 0.02; P = 0.023) and peak late diastolic transtricuspid valve velocity (0.46 ± 0.1 m/s vs 0.39 ± 0.08 m/s; P = 0.001), in women with GDM compared to controls. CONCLUSIONS: Our findings show that even a short period of exposure to hyperglycemia, as occcurs in women with GDM, is associated with significant maternal functional cardiac impairment at term. Given these findings, further study of postnatal maternal cardiovascular recovery after GDM pregnancy is warranted. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Cardiac maladaptation in obese pregnant women at term.

OBJECTIVE: Obesity is an increasing problem worldwide, with well recognized detrimental effects on cardiovascular health; however, very little is known about the effect of obesity on cardiovascular adaptation to pregnancy. The aim of the present study was to compare biventricular cardiac function at term between obese pregnant women and pregnant women with normal body weight, utilizing conventional echocardiography and speckle-tracking assessment. METHODS: This was a prospective case-control study of 40 obese, but otherwise healthy, pregnant women with a body mass index (BMI) of ≥ 35 kg/m2 and 40 healthy pregnant women with a BMI of ≤ 30 kg/m2 . All women underwent a comprehensive echocardiographic examination and speckle-tracking assessment at term. RESULTS: Obese pregnant women, compared with controls, had significantly higher systolic blood pressure (117 vs 109 mmHg; P = 0.002), cardiac output (6.73 vs 4.90 L/min; P < 0.001), left ventricular (LV) mass index (74 vs 64 g/m2 ; P < 0.001) and relative wall thickness (0.43 vs 0.37; P < 0.001). Diastolic dysfunction was present in five (12.5%) controls and 16 (40%) obese women (P = 0.004). In obese women, compared with controls, LV global longitudinal strain (-15.59 vs -17.61%; P < 0.001), LV endocardial (-17.30 vs -19.84%; P < 0.001) and epicardial (-13.10 vs -15.73%; P < 0.001) global longitudinal strain as well as LV early diastolic strain rate (1.05 vs 1.24 /s; P = 0.006) were all significantly reduced. No differences were observed in the degree of LV twist and torsion between the two groups. CONCLUSIONS: Morbidly obese, but otherwise healthy, pregnant women at term had significant LV hypertrophy with evidence of diastolic dysfunction and impaired deformation indices compared with pregnant women of normal weight. These findings are likely to represent a maladaptive response of the heart to volume overload in obese pregnancy. The impact of theses changes on pregnancy outcome and long-term maternal outcome is unclear. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Cardiac maladaptation in term pregnancies with preeclampsia.

OBJECTIVES: To study biventricular cardiac changes with conventional echocardiography and new echocardiographic speckle tracking technologies such strain, twist and torsion in pregnant women with preeclampsia at term and normotensive control term pregnant women. STUDY DESIGN: For this prospective single centre case-control study, we consecutively recruited 30 women with preeclampsia at term as cases and 40 healthy control term pregnant women. All women underwent transthoracic echocardiographic examination at the time point of inclusion into the study. MAIN OUTCOME MEASURES: Signs of systolic and/or diastolic cardiac maladaptation to the increased volume load associated with pregnancy. RESULTS: Conventional echocardiography revealed mild left sided diastolic impairment in the form of significantly increased E/E' in preeclampsia (7.58 ±â€¯1.72 vs. 6.18 ±â€¯1.57, p = 0.001) compared to normotensive controls, but no evidence of systolic impairment. With speckle tracking analysis, significant decreases in left ventricular global (-13.32 ±â€¯2.37% vs. -17.61 ±â€¯1.89%, p < 0.001), endocardial (-15.64 ±â€¯2.79% vs. -19.84 ±â€¯2.35%, p < 0.001) and epicardial strain (-11.48 ±â€¯2.15% vs. -15.73 ±â€¯1.66%, p < 0.001) as well as left ventricular longitudinal strain rate (-0.84 ±â€¯0.14 s-1 vs. -0.98 ±â€¯0.12 s-1, p < 0.001) and left ventricular early diastolic strain rate (0.86 ±â€¯0.30 s-1 vs. 1.24 ±â€¯0.26 s-1, p < 0.001) could be observed in women with term preeclampsia. CONCLUSIONS: The findings of this study demonstrate that pregnant women with term preeclampsia with minimal functional changes on conventional echocardiography, demonstrated significant subclinical myocardial changes on speckle tracking analysis.