The Type of Anesthesia Technique Does Not Have an Impact on 30-Day Mortality in Geriatric Patients Undergoing Lower Extremity Amputation

Lower extremity amputations performed in geriatric patients with peripheral vascular disease have high morbidity and mortality rates due to comorbid systemic diseases.¹ In the literature, factors such as increased age, diabetes mellitus, coronary artery disease, and chronic renal failure were associated with poor outcomes.² The 30-day mortality rate ranged between 5% and 15%.³ Considering the increase in the elderly population, the incidence of lower extremity amputation performed due to peripheral vascular disease will inevitably increase.

There are different views on the anesthesia technique to be applied to patients who have undergone lower extremity amputation.^4,5 The generally accepted approach is that while the regional anesthesia technique is suggested for patients with pulmonary problems, the general anesthesia technique is more appropriate for patients who take antiplatelet medications or anticoagulants.⁶ The selection of the anesthetic technique in amputations in geriatric patients who have limited functional capacity may be important in terms of clinical outcomes and mortality rates.

The purpose of this study was to determine the appropriate anesthetic technique for geriatric patients who have undergone amputation due to peripheral vascular disease.

Methods

In total, 496 patients aged older than 65 years who underwent major lower extremity amputation (MLEA; above knee/below knee) between 2008 and 2015 were included in the study after obtaining the approval of the Institutional Research and Ethics Committee. Our institutional ethics committee waived informed consent due to the retrospective design of the study. Fifty-five patients who did not have adequate records and who did not undergo major amputation were excluded. The remaining 441 patients were retrospectively evaluated. From the medical records in the electronic system, the demographic characteristics, preoperative hemoglobin levels, and comorbid diseases (hypertension, diabetes mellitus, coronary artery disease, congestive heart failure, cardiac intervention history, chronic renal failure, chronic obstructive pulmonary disease, and smoking status) of the patients were recorded. The medications used by the patients (beta blockers, calcium channel blockers, digoxin, nitrates, statins, antiplatelet drugs, and anticoagulant drugs) and American Society of Anesthesiology (ASA) scores were recorded. The anesthesia technique applied during surgery, the durations of anesthesia and surgery, and whether or not a blood transfusion was performed were noted. The patients' 30-day mortality and cardiac and pulmonary complication [postoperative ventilation support longer than 24 hours; pneumonia; myocardial infarction (MI); and arrhythmia] rates were calculated. The 30-day mortality rates were calculated using data from the Republic of Turkey Ministry of Interior, General Directorate of Population and Citizenship Affairs using the patients' identification numbers. The patients' deep vein thrombosis (DVT), surgical site infection, and urinary tract infection rates, and length of stay in the intensive care unit and in the hospital were calculated.

The decision to perform amputation and the level of amputation in case of persistent infection causing loss of limb function, necrosis, gangrene, tissue necrosis, or life-threating sepsis symptoms were determined by the orthopedic surgeon in charge and on cardiovascular surgery consultation. The patients were divided into 2 groups according to the anesthesia technique applied: regional anesthesia (RA) and general anesthesia (GA). The patients for whom the spinal or combined (spinal–epidural) technique were applied were included in the RA group. Patients in whom endotracheal intubation was performed or those who were operated under general anesthesia with a laryngeal mask were included in the GA group.

Number Cruncher Statistical System 2007 Statistical Software (Kaysville, UT, USA) was used for statistical analyses. When evaluating data, in addition to the descriptive statistical methods (mean, standard deviation, median, frequency, and rate), Student's t-test was used to compare parameters with normal distributions between the groups, and the Mann–Whitney U test was used to compare parameters without normal distribution. In the comparison of qualitative data, Pearson's χ² test, Yates' continuity correction test, and Fisher's exact t-test were used. The results were evaluated at 95% confidence interval, and P < 0.05 was considered statistically significant.

Results

In 244 of the 441 patients who were included, regional anesthesia had been applied, while in 197, general anesthesia had been applied. The average age of the patients was higher in the RA group (P = 0.001). The average length of stay in the hospital was longer in the GA group (P = 0.001). The demographic data and descriptive characteristics of the patients are shown in Table 1.

Table 1  Comparison of descriptive characteristics by type of anesthesia

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When the groups were compared in term of comorbidities, the amputation rates were found to be higher in patients who received regional anesthesia (P = 0.001). There was no significant difference in comorbidities (Table 2). The use of antiplatelet drugs was determined to be higher in the GA group compared to the RA group (P = 0.001; Table 3).

Table 2  Evaluation of comorbid diseases by groups

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Table 3  Evaluation of drugs used by groups

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No significant difference was found between the groups in terms of mortality, MI, DVT, and pulmonary complications. In the patients receiving general anesthesia, the preoperative hemoglobin levels were lower (P = 0.045); erythrocyte transfusion (P = 0.016) and fresh frozen plasma transfusion (P = 0.008) rates were significantly higher (Table 4).

Table 4  Evaluation of mortality and complication features of the groups

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Discussion

We investigated the effect of anesthesia techniques applied during MLEAs in geriatric patients on 30-day mortality and early complication rates. We determined that the anesthesia technique does not have an impact on mortality and complication rates. The general anesthesia technique was more preferred in the patients who are under antiplatelet drugs, and length of stay in the hospital was longer in the patients who are operated under general anesthesia.

MLEAs performed due to peripheral arterial diseases have a poor prognosis because of serious complications and an approximate 30% 2-year mortality rate.⁷ While there are studies in the literature investigating the effect of the anesthesia technique applied to patients who had revascularization on clinical outcomes, there are a limited number of studies where anesthesia techniques were compared in patients who underwent a major amputation.⁶

Regional anesthesia has many theoretical advantages over general anesthesia.^6,8 These include peripheral vasodilation, increase in blood flow, lower risk of thrombosis, and less pain severity.^8,9 In a meta-analysis where geriatric patients undergoing different types of surgery were compared, mortality rates, MI and DVT incidences, and blood transfusion rates were lower in patients who received regional anesthesia.⁸ The patients who underwent MLEAs were not considered as a subgroup in this study. In another meta-analysis where patients who had lower extremity revascularization were evaluated, pulmonary complications were lower in the RA group, but there was not sufficient evidence to compare other parameters.⁶ Chery et al¹⁰ have reported that pulmonary complications and arrhythmia are observed less often in the RA group for MLEA. Contrary to their result, there is a recent study where mortality, hospital length of stay, and postoperative complication rates were similar in MLEA patients who received general and regional anesthesia.¹¹ When general anesthesia and peripheral nerve block in lower extremity amputations were compared, they were reported to have similar effects on 30-day mortality rates.¹² Given the fact that postsurgical complications are usually associated with the applied surgical procedure, it is difficult to evaluate complications associated with the anesthesia technique only. It should be noted that in geriatric patients with a quite limited physiologic reserve, complications arise because of multifactorial reasons.

In our study, the patients in the RA group were determined to have a higher average age and a higher presence of a previous amputation. On the other hand, in patients in the GA group, the length of hospital stay and transfusion rates were found to be higher. High transfusion rates in in the GA group can be explained by the fact that they had lower preoperative hemoglobin levels. No significant difference was detected between the groups in terms of mortality and postoperative complication rates. The length of hospital stay in the GA group was longer; therefore, regional anesthesia is more appropriate in terms of patient costs.

In the literature, three studies are similar to ours for MLEA in the geriatric patient population. The first was published in 1983 and the other two are more recent.^10,11,13 In this context, given the limited number of comparative studies that examine the geriatric subgroup, we believe that our findings are valuable. The limitations of our study are its retrospective design, low number of patients, the fact that other perioperative data that could have had an impact on the results were not evaluated, and the inclusion of patients who began with regional anesthesia but then received general anesthesia in the GA group.

Conclusion

In geriatric patients who will undergo MLEA, regional anesthesia techniques may be preferred due to the shorter length of hospital stay and theoretical advantages. However, considering the general functional status of patients and magnitude of the surgery to be undergone, the importance of patient-based evaluation should be remembered.