Level of Block Achieved with 1.6 ml of 0.75% Bupivacaine along with the Hemodynamic Variations after Spinal Anesthesia: A Prospective Study among Pakistani Women undergoing Elective Caesarean Sections

Objective: To evaluate the interval of time required for the maximal sensory block along with hemodynamic variations of pulse and blood pressure after spinal anesthesia among Pakistani women undergoing elective Caesarean Sections. Place and Duration: From September 2012 to March 2013. Study Design: Prospective Study Materials and Methods: A total of 100 parturients categorized in the American Society of Anesthesia classification ASA – I and II, aged in between 20-40 years presenting with single pregnancy for the elective caesarean section were recruited in the study. Spinal anesthesia was given using 25 G, Quincke needle after ascertaining free clear flow of CSF(cerebrospinal Fluid),and 1.6ml of 0.75% hyperbaric bupivacaine was injected. Block level was assessed every 2 minutes with sensation to touch, pinprick, and cold ice saline for 30 minutes. Monitoring of blood pressure, pulse and pulse oximeter were continuous at every two minutes interval. Procedure was started as the maximal sensory T4 block confirmed. Maternal hypotension during procedure was treated with the bolus of 50% of the initial dose of vasopressor. Heart rate below 50 beats per minute accompanied by hypotension was treated with 0.5mg of Atropine. Results: The maximal sensory block achieved was up to the level of 3rd thoracic site(T3) with a range of T2-T7.So our study clearly reflects that even a volume of 1.8ml ,0.75mg of bupivacaine is sufficient to achieve a reasonable sensory block level to conduct cesarean section. The mean±S.D time for the block to reach maximal sensory level was 9.2±4.6 minutes. The maximal decrease in pulse, systolic B.P and diastolic B.P were 15.4±8.7/min, 33.6±11.3 mmHg and 18.2±7.8 mmHg respectively from the baseline, keeping the study participants almost hemodynamically stable with in the normal physiological range without making the attending anesthetists to proceed emergency protocols for the management of adverse effects of spinal anesthesia. Nausea, vomiting and shivering were present among 52%, 34% and 16% respectively of our study participants. Conclusion: .6ml of 0.75% injection bupivacaine injected via spinal needle in the subarachnoid space at the level of L3-L4 among Pakistani women undergoing elective cesarean section is sufficient to provide an adequate T4 sensory block.