Clinical Study Of Tourniquet Pain In Ankle Surgery

Part 1 Feasibility of pain sensitivity questionnaire in predicting tourniquet pain in ankle surgeryObjective: Tourniquet is often used in foot and ankle surgery to reduce intraoperative bleeding.However,with the extension of the use time of tourniquet,patients often complain of pain and discomfort at the place where tourniquet used.Due to the difference in pain sensitivity among individuals,the pain degree of tourniquet during operation is different.The Pain Sensitivity Questionnaire(PSQ)can predict the postoperative pain of patients.However,it is not clear whether it is suitable for patients with intraoperative tourniquet pain.The purpose of this study is to explore the value of sensitivity questionnaire in predicting patients’ intraoperative tourniquet pain and analyze the related factors affecting the pain of intraoperative tourniquet.Methods: 120 patients aged 18 to 60 years old,with body mass index(BMI)of 19.6 to29.9 kg/m2,were selected for foot surgery in the First Affiliated Hospital of the University of Science and Technology of China.The American Society of Anesthesiologists(ASA)was rated as Grade I or Grade II,regardless of gender.Pain sensitivity questionnaire(PSQ)and Self-Rating Anxiety Scale(SAS)were completed before operation.The anesthesia method is popliteal fossa sciatic nerve block combined with femoral nerve block under the guidance of ultrasound.The proximal thigh tourniquet is used,and the pressure is set as systolic blood pressure(SBP)+100 mm Hg.According to the PSQ score of patients,the patients were divided into PSQ<6.5 groups(the low sensitivity group);PSQ ≥ 6.5 group(high sensitivity group).Record the occurrence time of tourniquet pain VAS ≥ 4 points in all patients;Record the amount of remedial analgesics and the number of patients who changed to general anesthesia in the two groups;There was no tourniquet related pain and the feeling and movement of the affected side of the limb after the operation.The correlation between PSQ score and the occurrence time of VAS ≥ 4 points of tourniquet pain during operation was analyzed.The risk factors of VAS ≥ 4 points of tourniquet pain in 30 minutes were screened by multivariate logistic regression analysis.Results: PSQ score was negatively correlated with the occurrence time of VAS ≥ 4 points of tourniquet pain(r=-0.763,P<0.05);Patients with high pain sensitivity have a higher need for analgesic drugs(P < 0.05).Multivariate logistic regression analysis showed that PSQ score ≥ 6.5(OR=185.8,95% CI=32.1-1076.8),gender(female,OR=9.27,95%CI=1.85-46.65),age(OR=0.92,95% CI=0.842-0.995)were risk factors for reporting a tourniquet pain ≥4 VAS units within 30 min(P<0.05).Conclusion: PSQ score is related to the occurrence time of tourniquet pain during operation.The pain sensitivity questionnaire can predict the occurrence time of tourniquet pain during ankle surgery.Patients with high PSQ score may have earlier occurrence of tourniquet pain during operation.In addition,sex and age also affect the time of having intraoperative tourniquet pain.Part 2 Effect of humidified high flow nasal cannula on tourniquet pain during operationObjective: Tourniquet is often used in foot and ankle surgery to reduce intraoperative bleeding.However,tourniquet pain is the most common complication when using tourniquet.With the extension of use time,patients are often unbearable.Some studies suggest that tourniquet pain may be related to nerve fiber,muscle and skin ischemia;Animal studies have confirmed that the concentration of adenosine triphosphate,oxygen tension and glycogen in the extremities using tourniquet decreased,while the concentration of lactic acid and carbon dioxide tension increased.These subtle changes in tissue metabolism may be one of the causes of pain.Some studies have found that oxygen inhalation can reduce the pain of the tourniquet.However,when the flow of oxygen inhalation through the nasal catheter is too large,it may cause damage to the nasal mucosa of patients,and oxygen inhalation through the mask is also easy to cause discomfort to patients.Humidified high flow nasal cannula(HFNC)is a method that has attracted more attention in recent years.It has the characteristics of accurate temperature regulation and humidification fully close to physiological airflow by using the nasal catheter to input the heated and humidified air-oxygen mixture into the airway.However,it is not clear whether nasal high-flow oxygen inhalation can also reduce the tourniquet pain,or even better than mask oxygen inhalation.The purpose of this study is to explore the effect of humidified high flow nasal cannula on the pain of tourniquet during operation,so as to provide reference for clinical practice.Methods: A total of 18~60 years old patients with body mass index(BMI)of 19.6~29.9 kg/m2 and American Association of Anesthesiologists(ASA)grade I or II were randomly divided into two groups(23 patients in each group): humidified high flow nasal cannula(group H)and mask oxygen inhalation group(group B).Use ultrasound-guided popliteal sciatic nerve block combined with femoral nerve block,use proximal thigh tourniquet,and set the pressure as SBP+100mm Hg.After the block was confirmed to be effective,the patients in the humidified high flow nasal cannula group were given nasal high-flow oxygen,20 L/min,oxygen concentration 50%,temperature 35 ℃;The patients in the mask oxygen inhalation group were given oxygen through the mask,10 L/min,and the oxygen concentration was 50%.Record the occurrence time of tourniquet pain VAS ≥ 4 points in all patients;Before oxygen inhalation(T0)and when the tourniquet inflation time reaches 30 minutes(T1),2ml of radial artery blood was taken for blood gas analysis,and the Pa O2,Pa CO2,Lac and electrolyte levels in arterial blood were recorded.The VAS score of patients with tourniquet pain,blood pressure,heart rate and oxygen saturation were recorded every five minutes since the tourniquet inflation time reached 15 minutes.There was no tourniquet related pain and the feeling and movement of the affected side of the limb after the operation.Results: Compared with group H,patients in group B had tourniquet pain VAS ≥ 4 minutes earlier(P<0.05).Compared with group H,the number of patients with tourniquet pain VAS ≥ 4 in group B within 30 minutes was significantly higher(P<0.05).There was no significant difference in PH,Pa CO2,Pa O2,K+,Ca2+,Lac,H+ between the two groups before using tourniquet and oxygen inhalation.Compared with T0,the concentrations of Pa CO2 and H+ in arterial blood of group B were higher at T1(P<0.05),Pa O2 in arterial blood was higher in group H at T1(P<0.05).Compared with group H,Pa O2 in arterial blood of group B was significantly lower and H+ concentration was higher at T1(P<0.05).Conclusion: Humidified high flow nasal cannula can reduce the pain of tourniquet during operation,and can delay the arrival of the widely accepted pain threshold.