The study will be started after obtaining approval from the Institute Ethics Committee (IEC) and written & informed consent from the participants. Sixty potential participants fulfilling the eligibility criteria and willing to participate will be enrolled in this study. The details of the study will be explained to the participants prior to the procedure.

On admission of patients with features of severe pre-eclampsia, demographic and obstetric data of the patients will be noted. Basal vital parameters of the patients including SBP, DBP, MAP, HR, RR, SpO2 will be recorded. As per standard institutional protocol blood sample will be drawn and will be sent to the laboratory for analysis of CBC, LFT, RFT, Serum Electrolytes, Coagulation profile, Blood grouping/ cross matching, Blood sugars, Urine Routine Microscopy, HIV, HBsAg, HCV etc.

In Allen’s test, both hands were tested concurrently compressing one artery of each hand simultaneously. But in Modified Allen’s Test (MAT) each hand is examined separately. The subjects were asked to sit comfortably and instructed not to hyperextend their fingers or wrist. The radial artery and ulnar artery are compressed lightly simultaneously using both the thumbs of examiner to occlude both the arteries at wrist level and the subject will asked to clench and relax his hand three times till palm became blanched. The hand will then slowly open to a neutral position, and the examiner will remove the pressure from the ulnar artery. Time taken (in seconds) for the blanched hand to return to its normal color will be recorded by a stop watch. If the palmar arch is patent, then hand will become pink within 3-9 sec. If return of color does not occur within 9 s then it is termed as a positive MAT and is thought to preclude radial artery harvest. After performing the MAT, the results will be categorized as negative (up to 3 s), equivocal (3-6 s), borderline (6-9 s) and abnormal (>9 s) [10].

Under all aseptic precautions, blood sample will be drawn from radial artery and will be sent for arterial blood gas (ABG) analysis at the time of admission, six hours after admission, and then prior to delivery. After extraction of blood, the radial artery will be compressed using the sterile gauze for at least 5 min. The blood sample will be analyzed immediately avoiding any delay. In case if there’s a delay, then the sample will be placed on ice packs and will then be analyzed quickly. Any sample which we will not be able to analyze within half an hour from collection time will be discarded and then a fresh sample will be drawn for ABG analysis. Calibration of ABG machine will be done at regular intervals as per the guidelines of manufacturer.

Data regarding date, time, mode of delivery, anesthesia technique used for LSCS will be noted. Fetal APGAR score will be noted at 1 minute and 5 minutes after birth of the child.

Any adverse fetal outcome will also be noted