Datex ohmeda

Study visits took place at 9:30 AM. Height and weight were recorded using calibrated devices, and BMI was calculated. Body surface area (BSA) was calculated using the Haycock formula.³³ Age‐ and sex‐specific BMI z scores were used to define “normal weight” (>−2 and ≤1) and “overweight/obese” (>1) groups, based on the World Health Organization's normative data and z score definitions.³⁴ Waist circumference was measured according to standard practice, and age‐ and sex‐specific waist and waist:height ratio z scores were calculated.³⁵, ³⁶ Blood pressure (BP) was measured as the average of 2 to 3 measures over 10 minutes, after participants had been resting for 15 (interquartile range, 12–17) minutes, using an oscillometric device (Datex Ohmeda, General Electric, Boston, MA).

All imaging was performed on a 1.5 T CMR scanner (Avanto, Siemens Healthineers, Erlangen, Germany) using two spine coils and one body-matrix coil. A vector electrocardiographic system was used for cardiac gating. Brachial systolic (p-SBP), diastolic (DBP) and mean (MBP) blood pressures were measured during the CMR scan using automated oscillometric sphygmomanometry (Datex Ohmeda, GE Healthcare). Small-adult, adult and large-adult cuff sizes were chosen according to subject arm circumference and all measurements were taken from the patient’s right arm. Blood pressures were assessed at least 15 min into the scan protocol (at the time of flow imaging) to ensure acclimatization to the supine position.

BP and heart rate (HR) were measured using continuous finger-pulse photoplethysmography (CNAP, CNSystems Medizintechnik AG, Graz, Austria). Finger BP was calibrated against brachial arterial pressure. SAS (SAS_LEFT – left hemisphere, SAS_RIGHT – right hemisphere) signals were recorded using SAS Monitor (NIRTI SA, Wierzbice, Poland). Detailed description of SAS Monitor was provided previously^{22 (link)}. Oxyhaemoglobin saturation (SaO₂) was measured using a medical monitoring system (Datex-Ohmeda, GE Healthcare, Wauwatosa, WI, US). Gas samples from the mouthpiece were constantly analysed using the side-stream technique for end-tidal CO₂ (EtCO₂) with the metabolic module of the same medical monitoring system. All parameters were recorded continuously for further analysis, and BP and SAS signals were synchronized on a beat-to-beat basis^{22 (link)}.

Brachial systolic, diastolic and mean arterial blood pressures were measured from the right arm in all subjects using an MRI compatible oscillometric sphygmomanometer (Datex Ohmeda; General Electric, Boston, USA) during acquisition of MRI data. This enabled an optimum combination of blood pressure and flow data for calculating vascular indices. All blood pressure measurements were acquired with an appropriately sized arm cuff after the subject had been prone in the scanner for at least 10 min. Pulse pressure was the difference between systolic and diastolic blood pressure.

Effects of maternal injection of MgSO₄ on hemodynamic parameters in the fetal brain were analyzed at GD18 using a surgery approach associated with a laser speckle moorFLPI‐2 recording (MOOR Instrument, Axminster, UK). Pregnant mice received a low (100 mg/kg) and high (600 mg/kg) subcutaneous injection of MgSO₄ and were rapidly anesthetized with isoflurane using an isoflurane Vaporizer (Datex‐Ohmeda; GE Healthcare, Aulnay sous bois, France). Laparotomy was performed to allow access to the uterine horns. The abdominal cavity, especially the exposed uterine horn, was kept moist with warmed physiologic solution. During surgery, the body temperature of the mouse was maintained using a hotplate (Lab‐Line Instruments, Melrose Park, IL). Fetal cerebral blood flow dynamics were measured during 1 min with a pace of 15 pictures acquired per minute. In utero quantification of the fetal cerebral blood flow was performed between 20 and 30 min after the injection of MgSO₄ to the mother. After measurements, the uterine horn was carefully replaced in the abdominal cavity. The muscles and skin of the surgical wound were sutured separately with sterile Silk Suture Prolene 6‐0, MPP2832H (Ethicon, Lidingö, Sweden).

Brachial systolic, diastolic and mean arterial BPs (SBP, DBP, MBP) were measured using a CMR compatible oscillometric sphygmomanometer (Datex Ohmeda; General Electric Healthcare, Boston, Massachusetts, USA) during CMR image acquisition. This enabled optimum combination of BP and flow data for calculation of vascular indices. All BP measurements were acquired with an appropriate sized arm cuff after the subject had been lying in the scanner for at least 10 min. Pulse pressure (PP) was the difference between SBP and DBP.

Infusion doses of 2% pentobarbital sodium (2.5 ml/kg) were administered through the outer vein on the edge of the ear for anesthesia. A left central intravenous catheter (4FR, 22GA (13 cm); Arrow, USA) was inserted 5 cm into the jugular vein. A left arterial catheter (20G; BD, USA) was inserted 2 cm into the internal carotid artery. After tracheotomy, rabbits were ventilated (Engström Carestation; Datex-Ohmeda (GE Healthcare), USA) with a fraction of inspired oxygen of 50%, a tidal volume of 10 ml/kg, a positive end-expiratory pressure of 0 cmH₂O, and a respiratory rate of 35 breaths/min.