4.1 Baseline characteristics of selected participants
A total of 477 participants were selected for the final data analysis after screening by inclusion and exclusion criteria (see Figure 1 for a flow chart). We showed baseline characteristics of these selected participants in table 1 according to two types of anesthesia. In general, the average age of the 477 selected participants was 80.17± 7.671 years old,and about 0.25577% of them were male. No statistically significant differences were detected in age,gender,no complications,hypertension,diabetes,heart disease,central nervous system disease among different anesthesia groups (P > 0.05).There were statistical differences in pulmonary diseases among different anesthesia groups (P <0.05).
In Table 2, we show baseline and post-block hemodynamic values for these selected participants, as well as differences in mean arterial pressure and heart rate between the two groups, and the use of vasoactive drugs.There were no significant differences in baseline systolic blood pressure, baseline diastolic blood pressure, baseline mean arterial blood pressure and baseline heart rate between the two groups (P>0.05).The systolic blood pressure after block, diastolic blood pressure after block, mean arterial pressure after block and heart rate after block in the CSEA group were all lower than those in the CLPSB group, and the difference was statistically significant (P <0.05).The difference between baseline mean arterial pressure and post-block mean arterial pressure was statistically significant between the two groups (P<0.05), and the CSEA group was significantly lower than the CLPSB group. There was no statistical difference between baseline heart rate and post-block heart rate between the two groups (P>0.05). The proportion of vasoactive drugs used in the CSEA group was higher than that in the CLPSB group, and the difference was statistically significant (P<0.05).
4.2 Unvariate analysis
We listed the results of univariate analyses in Table 3. By univariate linear regression. First of all,we found that age,gender,diabetes,heart disease,lung disease,central nervous system disease were not associated with ∆MAP and ∆HR(P>0.05);univariate analysis showed that hypertension were positively correlated with ∆MAP and ∆HR (P<0.05).[12]Then,we found that age,gender,diabetes,hypertension,lung disease,central nervous system disease were not associated with vasopressor (P>0.05);univariate analysis showed that heart disease were positively correlated with vasopressor (P<0.05).
4.3 Results of unadjusted and adjusted linear regression
In this study, we constructed three models to analyze the independent effects of two types of anesthesia on ∆MAP,∆HR,vasopressor (unvariate and multivariate linear regression ). The effect sizes (β and OR,β for ∆MAP and ∆HR,OR for vasopressor) and 95% confidence intervals were listed in Table 4-6. In the unadjusted model (crude model),the effect size of 6.80mmHg for ∆MAP in unadjusted model means that mean arterial pressure change was higher in CSEA group than in CLPSB group(6.80, 95%CI (4.27, 9.34)),the difference was statistically significant (P < 0.05). In the minimum-adjusted model (model 1), mean arterial pressure change was higher in CSEA group than in CLPSB group (7.02,95% CI (4.47, 9.56)),the difference was statistically significant (P < 0.05). In the fully-adjusted model (model 2) (adjusted all covariates presented in table 1), mean arterial pressure change was higher in CSEA group than in CLPSB group (6.88, 95% CI (4.33, 9.42)),the difference was statistically significant (P < 0.05).In the unadjusted model (crude model),the effect size of 0.71bmp for ∆HR in unadjusted model means that heart rate change was higher in CSEA group than in CLPSB group(0.71, 95%CI (-1.39, 2.81)),the difference was not statistically significant (P > 0.05). In the minimum-adjusted model (model 1), heart rate change was higher in CSEA group than in CLPSB group (0.59,95% CI (-1.51, 2.70)),the difference was not statistically significant (P > 0.05). In the fully-adjusted model (model 2) (adjusted all covariates presented in table 1), heart rate change was higher in CSEA group than in CLPSB group (0.50, 95% CI (-1.62, 2.62)),the difference was not statistically significant (P > 0.05).In the unadjusted model (crude model),the effect size of 2.29 for vasopressor in unadjusted model means that use of vasopressor was higher in CSEA group than in CLPSB group 129%(2.29, 95%CI (1.22, 4.30)),the difference was statistically significant (P < 0.05). In the minimum-adjusted model (model 1), use of vasopressor was higher in CSEA group than in CLPSB group 141%(2.41,95% CI (1.28, 4.54)),the difference was statistically significant (P < 0.05). In the fully-adjusted model (model 2) (adjusted all covariates presented in table 1), use of vasopressor was higher in CSEA group than in CLPSB group 137%(2.37, 95% CI (1.24, 4.53)),the difference was statistically significant (P < 0.05).
4.4 Subgroup analysis
We used age,gender,no complications,hypertension,diabetes,heart disease,lung diseases,central diseases as the stratification variables to observe the trend of effect sizes in these variables (Figure 2-4). No significant heterogeneity was found in all subgroups (P>0.05).Found that central disease patients who applied probability increase use of vasopressor(OR 6.44,95%CI (1.46, 28.47),P=0.0662). Other results of the subgroup analysis were consistent with the preliminary results.