| Background and OBJECTIVE: Total hip replacement is the main surgical method for the treatment of femoral neck fracture and femoral head necrosis in elderly patients.Its safety and effectiveness have been recognized,but its complications to varying degrees still threaten the life safety of patients.With the development of visualization technology and the wide application of ultrasound,researchers have found that air embolism is one of the most frequent but easily ignored complications in total hip replacement.The clinical manifestations caused by air embolism are lack of specificity.In mild cases,there may be no clinical manifestations,and in severe cases,there may be serious complications such as cardiac arrest or even death.Most of the air embolism occurred in small volume of micro gas plugs.At present,only some literatures describe the observation of intraoperative air embolism,but few literatures conduct quantitative analysis of micro-air embolism.In this study,Doppler ultrasound was used to dynamically monitor the occurrence of microthrombus during femoral prosthesis implantation in elderly patients with total hip replacement,and to analyze the correlation between the quantity of microthrombus and hemodynamic fluctuations,so as to diagnose microthrombus more quickly,treat it in time,and improve the prognosis of patients.Methods: A total of 90 elderly patients aged 60 to 80 years old,ASA grade I-III,who underwent unilateral anterior total hip replacement under elective combined with block anesthesia in The Second Affiliated Hospital of Da Lian Medical University from December 2021 to August 2022 were selected.During the operation,Doppler ultrasound was used to observe the occurrence of micro air embolus during the implantation period of femoral prosthesis.The area of embolus accounted for the area of right atrium was represented by S.No obvious embolus was recorded as S0;S<5% is denoted as S1;5%≤S < 10% is denoted as S2;10%≤S < 15% is denoted as S3;15%≤S < 30% is denoted as S4;S≥30% is denoted as S5.Mean invasive arterial pressure(MAP),heart rate(HR),and pulse oxygen saturation(Sp O2),arterial partial pressure of oxygen(Pa O2)were recorded 1min before implantation(T0),when the femoral prosthesis is placed(T1),3min after implantation(T2),5min after implantation(T3),and 10 min after implantation(T4).Operation time,blood loss,chest tightness,chest pain,cough and other symptoms were recorded.Intraoperative blood pressure and heart rate fluctuations greater than 20% were recorded as cyclic fluctuation events,and related vasoactive drugs were given according to the changes,and the type and dosage of drugs were recorded.A 5% drop in Sp O2 was recorded as blood oxygen fluctuation,and oxygen flow was increased according to the situation,and measures such as head low level were given;Arrhythmia events were recorded separately;During the operation,if the patient has severe dyspnea,hypoxemia,uncorrectable arrhythmia,or cardiac arrest that cannot be corrected by oxygen inhalation,the surgeon should be informed to stop the operation immediately and take appropriate treatment to maintain the stable vital signs.Results: 1.Among the 90 cases of total hip replacement,37 cases were detected by Doppler ultrasound,with an incidence of 42.2%,including 16 cases(17.78%)in S1,19cases(21.11%)in S2,2 cases(2.22%)in S3,and 0 cases in S4 and S5 respectively.Among them,there were 2 cases(3.77%)of S0 hemodynamic fluctuation events,1 case(6.25%)of S1,9 cases(47.37%)of S2,and 2 cases(100%)of S3.There was no statistically significant difference in the incidence of different grades of air embolism(P> 0.05),but there was statistically significant difference in the incidence of hemodynamic fluctuation events in different grades of air embolism(P=0.000).2.At T1,MAP of S0 and S1 had no significant difference(P > 0.05),while MAP of S2 and S3 was significantly lower than that of S0(S2-S0 P=0.000;S3-S0 P=0.010);At T2,MAP of S0,S1 and S3 had no significant difference(P > 0.05),while MAP of S2 was significantly lower than that of S1(P=0.000).At T3 and T4,there was no significant difference in MAP between S1,S2,S3 and S0(P > 0.05).There was no significant difference in HR between S1,S2,S3 and S0 at different time(P > 0.05).There was no significant difference in the Pa O2 of emboli at all levels before and 30 min after the impact(P > 0.05).There was no significant difference between S1 and S0 when hammering(P > 0.05),but there was significant difference between S2 and S3 and S0(S2-S0 P=0.000;S3-S0 P=0.000).3.In S0,there was no statistically significant difference between MAP at different time and T0 time(P > 0.05);In S1,there was no statistically significant difference between MAP at different time and T0 time(P > 0.05).In S2,the MAP at T1 and T2 decreased significantly compared with that at T0(MAP1-MAP0 P=0.000;MAP2-MAP0 P=0.000),there was no significant difference in MAP at T3 and T4 compared with T0(P > 0.05).In S3,the MAP at T1 decreased significantly compared with that at T0(P=0.016),and there was no significant difference between the MAP at T2,T3 and T4 and that at T0(P > 0.05).There was no significant difference in Pa O2 between S0 and S1 before and after hammering(P > 0.05).Compared with Pa O2 before hammering,S2 decreased significantly(P=0.000 during hammering--before hammering).Compared with Pa O2 before hammering,S3 significantly decreased(P=0.027 before hammering).There was no significant difference in Pa O2 of S1,S2 and S3 compared with S0 at 30 min after hammening.4.Among the 37 patients monitored with micro gas suppository,one patient had symptoms of cough,chest tightness and chest pain in S2,and one patient had two transient arrhythmia-ventricular premature beats.In S3,one patient experienced a decrease in pulse oxygen saturation of more than 5%;5.The implantation time of the prosthesis was significantly longer in the patients with microthrombus event than in the patients without microthrombus event(P=0.000),but there was no statistically significant difference in the amount of blood loss(P > 0.05).6.Use of vasoactive drugs: there were statistically significant differences in the number of ephedrine users under different embolus area(P=0.000);There was no significant difference in the number of patients receiving norepinephrine under different embolus area(P > 0.05).The larger the embolus area,the more vasoactive drugs used.Conclusions: 1.Not all micro-thrombus events will cause hemodynamic fluctuations,which is directly related to the area of micro-thrombus.When the area of the right atrium is more than 5%,the hemodynamics will fluctuate obviously.When the area of the micro air embolus accounted for more than 10% of the area of the right atrium,the occurrence of severe intraoperative hemodynamic fluctuations should be vigilant,and relevant intervention measures should be made in time.2.After the occurrence of circulation fluctuations during the operation,the symptoms can be alleviated in time and the hemodynamic stability can be maintained by administering vasoactive drugs,increasing oxygen flow,changing body position to head low and other measures. |
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