| BackgroundAccording to surveys,nearly 2 million people in China are burned each year,and 5,000 of them died.They are ranked 3rd in accidental deaths.Severe burns not only result in damage to the skin and mucous membranes,but also cause serious systemic reactions,metabolic disorders and dysfunction of the system and organs.Surgery is a common treatment for burn wounds,including eschar excision,eschar shaving,skin grafting,etc.No special treatment is required for anesthesia for mild burns.If there is severe burn in the local tissue and there is a large area and serious body injury occurs,metabolism,hemodynamics,and visceral function change will occur,which will bring certain challenges to anaesthesia.It is very important to maintain the ideal depth of anesthesia during the operation.The ideal depth of anesthesia can help the smooth operation and improve the quality of postoperative rehabilitation.Too shallow anesthesia may lead to intraoperative awareness,causing severe traumatic sequelae and mental health problems.Excessive anesthesia increases the risk of cardiovascular accidents.Narcotrend is a new brain electrical depth detection system developed by Hannover Medical University in Germany.The general electrode sheet is attached to any position on the head and the brain electrical signals can be collected and analyzed.The system automatically analyzes the Narcotrend classification and displays it on a colorful touch screen.The bispectral index(BIS)is also an ordinary electrode pad,but it needs to be attached to the fixed position of the head to analyze the non-linear relationship between waveforms to distinguish the EEG signals representing different depths of anesthesia.Narcotrend and BIS as a new type of anesthesia depth monitoring system can both reflect and control the depth of anesthesia better and be confirmed by anesthesia in non-burn patients.However,there are studies indicate that BIS is known intraoperative awareness within its recommended range of anaesthesia;studies such as Rundshagen et al.showed Narcotrend has no advantages in maintaining hemodynamic stability,reducing the dosage of narcotic drugs and improving the quality of postoperative recovery,in addition to the maintenance of the depth of anesthesia compared with the traditional method of regulating the depth of anaesthesia in the elective surgery.And because severe burns are often accompanied by hemodynamic instability due to early loss of fluids,early treatment with anti-shock therapy requires the use of "escharotomy + skin grafting" in some patients.This is also a second strike,which can easily lead to cardiovascular accidents during surgery.Therefore,although Narcotrend and BIS provide the possibility of accurate intraoperative anesthesia in severe burn patients,its clinical application value and safety need to be further evaluated.At the same time,the release of cytokines and excitatory amino acids,the production of oxygen free radicals,energy metabolism disorders,imbalance of calcium homeostasis and other factors caused by burns can lead to destruction of the blood-brain barrier and increased vascular permeability.Finally,it causes diffuse brain edema and brain dysfunction.Studies have shown that there may be a close relationship between the brain metabolism and the depth of anesthesia under anesthesia.However,there is no relevant research on the relationship between the depth of anesthesia and brain metabolism in severe burn patients and whether it has a protective effect on brain injury caused by burn surgery.PurposeThis article aims to study the significance of Narcotrend and BIS in the operative anesthesia of burn patients,and to explore whether different depths of anesthesia have a protective effect on burn-induced brain injury.Method1.Patients with severe burns required early escharectomy(<7 days)108 cases,and skin grafting were randomly divided into group A,group B,and group C.In group A,the Narcotrend anesthesia depth was graded from level DO to level D2;group B was controlled between 35 and 65 of BIS;and group C used traditional methods to maintain an appropriate depth of anesthesia(anesthesia based on patient's blood pressure,heart rate,clinical manifestations,etc.).The main observations included intraoperative maximum mean arterial pressure difference,intraoperative maximum heart rate difference,anesthetic dosage,and postoperative recovery quality.2.The first part of group B patients underwent intraoperative anesthesia adjustment according to BIS,in the severe group(High group)12 cases,BIS value 35?45;moderate group(Middle group)12 cases,BIS value 46?55;mild group(Low group)12 cases,BIS value was 56?65.Three milliliters of blood were collected before induction of anesthesia(T1),at the beginning of surgery(T2),at the end of surgery(T3),and when the tracheal tube was removed(T4).Jugular venous oxygen saturation(Sjv02),Arteriovenous Oxygen Difference(AVDO2),cerebral oxygen uptake(CEO2),content of lactic acid in jugular bulb(LV),arterial lactate content(LA),arterial-jugular venous blood lactic acid difference(AVDL),serum S100? and NSE consistency were measured,and cognitive ability were evaluated before and 24h after anesthesia finally.Results1.Compared with group C,the maximal mean arterial pressure difference between group A and group B was significantly lower(P<0.01);the maximum heart rate difference during the surgery was significantly lower(P<0.01);The dosage of propofol(P<0.01)and remifentanil was significantly decreased(P<0.01),and the spontaneous breathing recovery time was significantly reduced(P<0.01).The time of orientation recovery in grouP B was significantly shorter than that in group C(P<0.05).The time of awakening and extubation in group A was significantly shorter than that in group C(P<0.05).There was no significant difference in the above observations between group A and group B(P>0.05).2.In the SjvO2 test,the results showed that the three experimental groups significantly increased compared with T1 at T2(P<0.01),and then decreased significantly at T3 and T4 compared with T2(P<0.01),but there was no significant difference between T3 and T4(P>0.05).In the Low,Middle,and High groups,as the depth of anesthesia deepens,the blood oxygen saturation of the jugular bulb decreases,and is most significant at the T2 time point,with significant differences between groups(P<0.01);There was no significant difference between 3 groups at the T3 and T4(P>0.05).3.In the detection of AVDO2,the results showed that the three experimental groups significantly decreased compared with T1 at T2(P<0.01),and then significantly increased at T3 and T4,and compared with T2,the difference was statistically significant(P<0.01),but there was no significant difference between T3 and T4.In the Low group,Middle group and High group,with the deepening of the depth of anesthesia,the difference in arterial and venous blood oxygen content showed a downward trend,which was the most significant at the T2 time point,and the difference between the groups was statistically significant(P<0.01).However,there was no significant difference between the three groups at T3 and T4(P>0.05).4.In the determination of CEO2,the three experimental groups decreased significantly compared with T1 at T2(P<0.01),but significantly increased at T3 and T4 compared with T2(P<0.01),but there was no significant difference when compared T3 with T4(P>0.05).In the Low group,Middle group and High group,with the deepening of the anesthesia,the cerebral oxygen uptake rate showed a downward trend,which was the most significant at the T2 time point,and the difference between groups was statistically significant(P<0.01);There was no significant difference between the three groups in T3 and T4(P>0.05).5.In the measurement of lactic acid content in the jugular bulbs,the three experimental groups showed a significant increase in T2,T3,and T4 values compared with T1(P<0.01).In the Low group,Middle group and High group,with the deepening of the anesthetic depth,the content of lactic acid in the jugular bulb showed a decreasing trend,which was the most significant at the T3 time point,and the difference between the groups was statistically significant(P<0.01).This situation also existed at T2 and T4,but there was no significant difference between groups(P>0.05).6.In the determination of arterial lactate content(LA),the three experimental groups significantly increased compared with T1 at T2,T3,and T4(P<0.01).In the Low group,Middle group,and High group,arterial lactic acid content decreased with the deepening of anesthesia,and was most significant at the T3 time point.The difference between groups was statistically significant(P<0.01).T2 and T4 also existed,but there was no significant difference between groups(P>0.05).7.In the brain lactic acid production,that is,the difference in AVDL,three experimental groups significantly decreased compared with T,at T2(P<0.01)and increased significantly at T3 and T4 compared with T2(P<0.01).In the Low,Middle,and High groups,as the depth of anesthesia deepens,the difference in lactate levels between the arteries and veins shows a decreasing trend,and at the T2 and T3 time points,the High group decreases significantly compared with the Low group and the Middle group(P<0.01);High group was significantly lower than the Low group at T4(P<0.01),but compared with the Middle group,the difference was not statistically significant(P>0.05).8.In the detection of serum S-100? protein,serum concentrations of the three experimental groups at T2,T3,and T4 were significantly higher than those at T1(P<0.01),and then gradually decreased after T3,and T4 was significantly declined from T3.(P<0.01).In the Low group,Middle group and High group,the serum S-100? protein concentration decreased with the deepening of the anesthetic depth,and was most significant at the T3 and T4 time points.The difference between the groups was statistically significant(P<0.01)..9.In the serum NSE protein assay,serum NSE concentrations in the three experimental groups at T2 and T3 were significantly higher than those at T1(P<0.01),and then gradually decreased after T3,and decreased significantly at T4 compared with T3(P<0.01).In the Low group,the Middle group and the High group,the serum S-100? protein concentration showed a decreasing trend as the depth of anesthesia deepened,and the differences between the groups at the T2,T3,and T4 time points were statistically significant(P<0.01).10.In the preoperative and postoperative evaluation of the cognitive ability of each group in 24h,it was found that the MMSE score was significantly lower in the Low group in 24 hours after surgery compared with preoperative(P<0.05);the reduction in the Middle group and High group compared with preoperative was not statistical significant(P>0.05).Compared with the Low group,Middle group and High group in 24 hours after operation,it was found that the MMSE score showed an upward trend with the deepening of the anesthetic depth,and the difference between the High group and the Low group was significantly different(P<0.05),but there was no significant difference between the Middle group and the Low and High groups(P>0.05).Conclusion1.Narcotrend and BIS help maintain hemodynamic stability during the operation of burn patients,reduce anesthetic dosage,and improve postoperative recovery.2.By monitoring the BIS to guide the anesthesia of burn patients,it can better control the depth of anesthesia and help prevent and reduce the occurrence of brain injury.3.Deeper anesthesia can reduce the brain damage after general anesthesia of burn patients and have a protective effect on the brain. |
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