Effects Of Controlled Hypotension On Hemodynamics And Tissue Oxygen Delivery And Oxygen Consumption In Spinal Operation

Objective To observe the effects of nitroglycerin and remifentanil on perioperativehemodynamics, oxygen delivery and oxygen consumption of tissue in spinal surgery, andpostoperative recovery after anesthesia.Methods Forty patients, ASAI-?, scheduled for the posterior lumbar interbody fusion, wererandomly divided into two groups: Nitroglycerin group (group N) and Remifentanil group(group R), each group had twenty patients. Both group used the intravenous inhalationalanesthesia method, both group were given fentanyl0.05-0.1mg every time to maintain analgesia,the inspired concentration of sevoflurane was controlled less than2MAC to maintain the value ofBIS during40to60, and cis-atracurium was discontinuous apply during the operation. Startedcontrolled hypotension when the surgery begun. Nitroglycerin group was given0.5?g kg-1min-1for an initial infusion rate, remifentanil group was given0.1?g kg-1min-1for an initial infusionrate. The infusion rate was adapted according to hypotension. Mean arterial pressure wassustainted55-65mmHg or reduction30%of the baseline till the procedure of surgery wasfinished. Recorded in the records of patients10min before controlled hypotension (T1),step-down after10min (T2),30min (T3),60min (T4),90min (T5), stop the buck after10min (T6),30min (T7) of the HR, SBP, DBP, MAP, SpO2, PETCO2, monitored the CI, SVI and SVRI withFlotrac/vigileo System. Meanwhile, collected the artery blood gas, recorded the value of PaO2,SaO2, PvO2, ScvO2, worked out DO2I, VO2I and O2ER, and collected T1, T5, T7momentmeasured artery blood gas and arterial blood lactate. Neuropsychology assessment was measuredusing MMSE at pre-operation and postoperative24hours, postoperative7days. Record bloodloss, transfusion quantities and urine output, meanwhile, observed the time of controlledhypotension and terminal time of surgery, the patient recovery time of spontaneous breathing,opening eyes and wake extubation. The adverse reactions of patients after surgery were alsorecorded. Moreover, make use of visual analogue score at15min after extubation.Results1.Hemodynamic: MAP during controlled hypotension was significantly lower than T1(P<0.05) in both groups; there was no significant difference between group N and group R(P>0.05). The HR in group N was significantly higher than group R in controlled hypotension (P<0.05). The CI in group R was lower than T1in controlled hypotension (P>0.05); The CI ingroup N was higher than T1in controlled hypotension (P>0.05); The CI in group N wassignificantly higher than group R in controlled hypotension (P<0.05). The SVI in group N waslower than T1in controlled hypotension (P<0.05), and significantly lower than group R incontrolled hypotension (P<0.05). The SVRI in two groups were lower in controlled hypotensionthan T1(P<0.05); between the two groups, The SVRI ingroup N were lower in controlledhypotension than group R (P<0.05).2.Monitoring of oxygen delivery and oxygen consumption?The PaO2in group N in controlledhypotension was significantly lower than T1(P<0.05); The PaCO2in group N in controlledhypotension was significantly higher than T1(P<0.05); between the two groups, The PaO2ingroup N were lower in controlled hypotension than group R (P<0.05), and The PaCO2in groupN were higher in controlled hypotension than group R (P<0.05). The CaO2and CvO2in twogroups were lower in controlled hypotension than T1(P<0.05); between the two groups, had nosignificant difference (P>0.05). The SCVO2in two groups had no significant difference incontrolled hypotension than T1(P>0.05); between the two groups, SCVO2had no significantdifference (P>0.05). The DO2I and VO2I in two groups were lower in controlled hypotensionthan T1(P<0.05); between the two groups, the DO2I and VO2I in group R were lower incontrolled hypotension than group N (P>0.05).The O2ER in two groups were higher in controlledhypotension than T1(P>0.05); between the two groups, O2ER had no significant difference(P>0.05).3. Biochemical indicators: The lactate between the two groups and among three time points ofeach group had no significant difference (P>0.05).4. Blood loss and operative field score: The group R of operative field score was lower than thegroup N (P<0.05); and the group R of blood loss was less than the group N (P<0.05).5. Anesthesia recovery: Comparison between two groups, group R has significantly shorterrecovery time of spontaneous breathing, opening eyes, extubation time (P<0.05). Both meanMMSE scores significantly decreased24hours after operations than24hours before operations(P<0.05), but MMSE scores in7days after operations was not significant different than24hoursbefore operations (P>0.05). At the time point of15minute after extubation, the visual analogscores in group N were significantly lower than group R (P<0.05). Conclusion1. By use of remifentanil and nitroglycerin during controlled hypotension in spinalsurgery, hemodynamics fluctuate significantly. Both methods could maintain the organ perfusionand the balance of oxygen delivery and consumption.2. Both remifentanil and nitroglycerin used during controlled hypotension in spinal surgery couldmake the target blood pressure levels attained, the blood loss was less and the surgical field wasmore clearer in the remifentanil group.3. Both remifentanil and nitroglycerin used during controlled hypotension in spinal surgery hadno adverse reaction, and the risk of cognitive impairment was not increased.