Cerebrospinal fluid and arterial acid-base equilibria in spontaneously breathing third-trimester pregnant women.

BACKGROUND: Acid-base status in full-term pregnant women is characterised by hypocapnic alkalosis. Whether this respiratory alkalosis is primary or consequent to changes in CSF electrolytes is not clear. METHODS: We enrolled third-trimester pregnant women (pregnant group) and healthy, non-pregnant women of childbearing age (controls) undergoing spinal anaesthesia for Caesarean delivery and elective surgery, respectively. Electrolytes, strong ion difference (SID), partial pressure of carbon dioxide ( [Formula: see text] ), and pH were measured in simultaneously collected CSF and arterial blood samples. RESULTS: All pregnant women (20) were hypocapnic, whilst only four (30%) of the controls (13) had an arterial [Formula: see text] <4.7 kPa (P<0.001). The incidence of hypocapnic alkalosis was higher in the pregnant group (65% vs 8%; P=0.001). The CSF-to-plasma Pco2 difference was significantly higher in pregnant women (1.5 [0.3] vs 1.0 [0.4] kPa; P<0.001), mainly because of a decrease in arterial Pco2 (3.9 [0.3] vs 4.9 [0.5] kPa; P<0.001). Similarly, the CSF-to-plasma difference in SID was less negative in pregnant women (-7.8 [1.4] vs -11.4 [2.3] mM; P<0.001), mainly because of a decreased arterial SID (31.5 [1.2] vs 36.1 [1.9] mM; P<0.001). The major determinant of the reduced plasma SID of pregnant women was a relative increase in plasma chloride compared with sodium. CONCLUSIONS: Primary hypocapnic alkalosis characterises third-trimester pregnant women leading to chronic acid-base adaptations of CSF and plasma. The compensatory SID reduction, mainly sustained by an increase in chloride concentration, is more pronounced in plasma than in CSF, as the decrease in Pco2 is more marked in this compartment. CLINICAL TRIAL REGISTRATION: NCT03496311.

Prophylactic intraoperative uterine artery embolization for the management of major placenta previa.

PURPOSE: Placenta previa is a major cause of maternal morbidity and mortality, associated to a high risk of peripartum hemorrhage and hysterectomy. We aimed to verify if prophylactic intraoperative uterine artery embolization in patients with placenta previa and at least one additional risk of bleeding (major placenta previa), can reduce hemorrhage, need for blood transfusions, peripartum hysterectomy and maternal morbidity. MATERIALS AND METHODS: We enrolled 76 patients with major placenta previa; a specific multidisciplinary protocol was designed for management, including ultrasound evaluation, hospitalization at 34 weeks, antenatal corticosteroids and scheduled cesarean section at 35-36 weeks. 44 patients (control group or CTR) were treated with elective cesarean section, 32 patients (embolized group or EMB) underwent selective catheterization of bilateral uterine arteries before cesarean section and subsequent uterine embolization. In both cases cesarean section was performed by a senior surgeon. RESULTS: Significant differences were found in term of intraoperative blood loss (CTR: 1431 ml; EMB: 693 ml); despite an high percentage of CTR patients had a bleeding greater than 1000 ml (56%), the need for blood transfusion was not significantly different between the two groups. Time of surgery was higher in the EMB group, considering that embolization procedure required approximatively 30 min. Three patients from the CTR group needed hysterectomy and ICU admission, compared to none in the EMB group. Duration of hospitalization and neonatal outcome were similar. Uterine embolization was not related to any short or long-term complications; return to normal menses and preservation of fertility were confirmed at follow up. CONCLUSIONS: Our results are promising, although we believe that a major contribution is referable to the multidisciplinary approach rather than the procedure itself. Nevertheless, we demonstrated the feasibility and safety of preventive uterine embolization in patients with placenta previa; in order to establish its prophylactic role in the prevention of peripartum hemorrhage, randomized trial should be carried out, on a larger population.