European Journal of Cardiovascular Medicine

Background: Preloading or the infusion of intravenous fluid prior to the induction of spinal anaesthesia has remained the cornerstone in the prevention of spinal induced hypotension for a long time. However, its efficacy in the adult young non-parturient population still has to be conclusively determined as most previous studies have been conducted in the parturient or the non-parturient elderly population. This prospective study was undertaken for the comparative evaluation of the clinical parameters associated with spinal induced hypotension following spinal anaesthesia among three groups, i.e. a no preload group, a crystalloid (Ringer’s lactate solution or RL group) preload and colloid (3.5% polygeline solution or polygeline group) preload, in elective   lower-abdominal or lower-limb surgery involving minimal blood loss, in a young adult (20 - 50 years) non-parturient population.  Material and Methods: 75 ASA-I and ASA-II, young adult (20 - 50 years), non-parturient patients undergoing elective lower abdominal or lower limb surgery, involving minimal blood loss, were randomly allotted into three groups of 25 patients each, in a double-blind clinical trial, to receive either no preload, 3.5% polygeline solution (10 mL kg-1), or Ringer’s lactate solution (20 mL kg-1), as a preload before spinal anaesthesia. The measurements of the heart rate (HR), systolic arterial pressure (SAP), mean arterial pressure (MAP) and the peripheral arterial oxygen saturation (SpO2) were recorded on a serial basis. Hypotension was defined as a decrease in the SAP of 25% or more from the baseline (before-preload) values. The various parameters indicative of the incidence, severity, duration and timing of spinal-induced hypotension (SIH) and the incidence of cardiovascular side-effects  such as bradycardia and arrhythmias in all the three groups were recorded.  Results: There was a significant difference in the incidence of SIH [68% (no-preload); 24% (polygeline) and 32% (Ringer’s lactate); P = 0.003], mean therapeutic requirement of vasopressor (mephentermine) (P = 0.001), mean minimum systolic arterial pressure    (P = 0.000), mean minimum systolic arterial pressure (as percent of baseline) (P = 0.000), mean maximal heart rate (P = 0.038), mean number of hypotensive episodes (P = 0.001), mean total duration of hypotension   (P = 0.000), and mean peripheral arterial oxygen saturation (SpO2)   (P = 0.000) following spinal anaesthesia between the control, polygeline and Ringer’s lactate groups. There was no significant difference in the incidence of SIH [24% (polygeline) vs. 32% (Ringer’s lactate);     P = 0.529], mean therapeutic requirement of vasopressor (mephentermine) (P = 0.781), mean maximal heart rate  (P = 0.923), mean number of hypotensive episodes (P = 0.923), mean total duration of hypotension (P = 0.926), mean peripheral arterial oxygen saturation (SpO2) (P = 0.803) following spinal anaesthesia between the polygeline and Ringer’s lactate groups. The mean minimum systolic arterial pressure (P = 0.037) and the mean minimum systolic arterial pressure (as percent of baseline) (P = 0.012) following spinal anaesthesia remained significantly higher in the polygeline group than in the Ringer’s lactate group. There was no significant difference in the mean time of recording of the minimum systolic arterial pressure   (P = 0.592), the mean duration of a hypotensive episode (P = 0.145) and the incidence of bradycardia [20% (no-preload); 12% (polygeline) and 16% (Ringer’s lactate); P = 0.743] following spinal anaesthesia between the control, polygeline and Ringer’s lactate groups. A significant difference, if any, in the incidence of arrhythmias following spinal anaesthesia between the three groups could not be found out because of the number of patients developing this side-effect was very less. Conclusion: The polygeline and Ringer’s lactate preload were effective in significantly reducing the incidence, severity and duration of SIH, and in maintaining significantly higher mean SpO2 following spinal anaesthesia, when compared to a  no-preload. However, there was no significant difference in the mean time of recording of the minimum systolic arterial pressure, the mean duration of a hypotensive episode or the incidence of bradycardia following spinal anaesthesia, between the three groups. There was no definite advantage of a polygeline preload over a Ringer’s lactate preload, as there was no significant difference between the two in so far as reducing the incidence, severity and duration of SIH is concerned, or in maintaining significantly higher mean SpO2 following spinal anaesthesia.