The effects of unilateral and bilateral spinal anaesthesia on hemodynamic parameters in patients surgically treated for inguinal hernia: Hemodynamic parameters and spinal anesthesia

Abstract

Introduction: Conventional bilateral spinal anaesthesia is commonly used for surgical treatment of inguinal hernia because it causes fast development of block with relatively small dosage of local anaesthetic; furthermore, it is easily administered, reduces the level of metabolic response to stress, reduces the incidence of deep venous thrombosis and respiratory depression. On the other hand, the main side effect is hypotension Objective: The goal of the research was to determine which of the two methods of spinal anaesthesia (conventional bilateral, achieved with regular dosage of long-lasting bupivacaine or hypobaric unilateral, achieved with combined application of bupivacaine and fentanyl) ensures higher hemodynamic stability during tension-free hernioplasty in patients from group I and II of ASA classification system. Methods: The research was conducted as a prospective, controlled clinical study with the total amount of 50 patients, males and females, and within the age span ranging from 17 to 77, who all had indications for surgical treatment of one-sided inguinal hernia under spinal anaesthesia. The hemodynamic parameters (heart rate, systolic, diastolic and mean arterial pressure) were measured during following intervals: T1 - during preanaesthetic visit, T2 - after premedication and the iv administration of Ringer's lactate solution, T3 - 15 minutes after the administration of spinal anaesthesia, T4 - after the surgical incision, T5 - intraoperatively, T6 - during the placement of the last surgical stitch on the skin, T7 - one hour postoperatively. Results: The results showed that the frequency of clinically relevant hypotension was statistically much higher in patients with bilateral spinal anaesthesia (24 %) when compared to patients administered with unilateral spinal anaesthesia (4%). Ten minutes after the application of spinal anaesthesia the mean arterial pressure has decreased by 20% when compared to basic values in group BB, and by 14% in group UB. During the same interval, systolic arterial pressure has decreased by 19% when compared to the primary values in group BB, and only by 10% in group UB. Diastolic arterial pressure, when compared to basic values has decreased by 21% during the same time interval in group BB, and by 18% in group UB. Effective analgesia was significantly longer in group UB (5.0 ± 0.7 hours) when compared to 3.6 ± 1.0 hours in group BB. Conclusion: Unilateral spinal anaesthesia achieved with hypobaric solution of bupivacaine with the addition of opioid fentanyl ensures better hemodynamic stability and longer effective analgesia when compared to bilateral spinal anaesthesia achieved with regular dosage of isobaric solution of bupivacaine.