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Print version ISSN 0034-7094
Rev. Bras. Anestesiol. vol.52 no.3 Campinas May/June 2002
Comparison between spinal, combined spinal-epidural and continuous spinal anesthesias for hip surgeries in elderly patients. A retrospective study *
Comparación entre raquianestesia, bloqueo combinado raqui-peridural y raquianestesia continua para cirugías de cuadril en pacientes ancianos. Estudio retrospectivo
Luiz Eduardo Imbelloni, TSA, M.D.; Lúcia Beato, M.D.
Anestesiologista da Casa de Saúde Santa Maria e Clínica São Bernardo
BACKGROUND AND OBJECTIVES: There are still
many questions involving study designs, data analyses and samples size which
regard to the demonstration of the benefits of regional anesthesia on patients
outcome. Database analysis and data acquisition in general cost less and require
less time as compared to large randomized controlled trials. This retrospective
study compares continuous spinal anesthesia, combined spinal-epidural and single
shot spinal anesthesia for hip surgery in elderly patients during a 4-year period,
to determine possible advantages and disadvantages of the three techniques.
METHODS: Anesthetic records of 100 patients receiving spinal anesthesia (Group 1), 100 patients receiving combined spinal-epidural block (Group 2) and 100 patients receiving continuous spinal anesthesia (Group 3) over a 4-year period were analyzed. All blockades were performed with patients in the left lateral position. Evaluated parameters were: puncture success, highest level of anesthesia, lower limb motor block, quality of anesthesia, need for additional doses, failures incidence, paresthesia, post-dural puncture headache, cardiovascular changes, mental confusion and delirium, blood transfusion and mortality.
RESULTS: There were no significant differences among groups regarding gender, age, weight and height. Group 2 patients were shorter as compared to groups 1 and 3. Mean bupivacaine doses were: 15.30 mg in group 1, 23.68 mg in group 2 and 10.1 mg in group 3. They showed statistical significant differences between groups (p < 0.01). There were significant differences (p < 0.01) in cephalad dispersion between groups 1 and 2, 1 and 3 and 2 and 3, being lower with continuous spinal and higher with combined spinal-epidural anesthesia. All patients presented total motor block (Bromage score = 3). There were no significant differences in arterial hypotension, bradycardia, paresthesia and blood transfusion. Postoperative mental confusion was observed in 19 patients, with no difference between techniques. There was no difference in mortality in the first postoperative week and in the first postoperative month.
CONCLUSIONS: Retrospective studies usually less and demand less time as compared to controlled studies. This retrospective study has shown that regional anesthesia techniques are related to a low mortality rate in the first postoperative month and to a low incidence of complications.
Key words: ANESTHETIC TECHNIQUES, Regional: combined epidural spinal block, continuous spinal anesthesia and spinal anesthesia
JUSTIFICATIVA Y OBJETIVOS: Diversas cuestiones
envuelven los estudios, las análisis y el tamaño de la muestra para
que sean demostrados los beneficios de la anestesia regional. Las análisis
de datos generalmente cuestan menos y requieren menos tiempo, cuando comparado
con un amplio estudio aleatorio controlado. Esta análisis retrospectiva
compara la raquianestesia continua, el bloqueo combinado raqui-peridural y la
raquianestesia simple para cirugías de cuadril en pacientes ancianos durante
cuatro años, para determinar las posibles ventajas y desventajas de las
MÉTODO: Fueron evaluadas 300 fichas siendo que: 100 pacientes recibieron raquianestesia simple (Grupo 1), 100 recibieron bloqueo combinado raqui-peridural (Grupo 2) y 100 recibieron raquianestesia continua (Grupo 3) en los últimos cuatro años. Todos los bloqueos fueron realizados en decúbito lateral izquierdo. Fueron evaluados: suceso de punción, nivel de analgesia, bloqueo motor de miembros inferiores, calidad de la anestesia, necesidad de complementación, incidencia de fallas, parestesias, cefalea pós-punción, alteraciones cardiovasculares, confusión mental y delirium, transfusión sanguínea y mortalidad.
RESULTADOS: No existe diferencia significativa entre los grupos en relación a la edad, peso y sexo. Los pacientes del grupo 2 fueron menores de que los del grupo 1 y 3. Las dosis utilizadas fueron de 15,30 mg de bupivacaína en el grupo 1; 23,68 mg en el grupo 2 y 10,10 mg en el grupo 3. No fue encontrada diferencia significativa (p < 0,01) entre los grupos, siendo menor con la raquianestesia continua y mayor con el BCRP. Existe una diferencia significativa (p < 0,01) en la dispersión cefálica entre los grupos 1 y 2, 1 y 3 y 2 y 3, siendo menor con la raquianestesia continua y mayor con el BCRP. Todos los pacientes presentaron bloqueo motor completo. No existe diferencia significativa en relación a hipotensión arterial, bradicardia, parestesia y necesidad de sangre. Diecinueve pacientes presentaron confusión mental en el pós-operatorio, sin diferencia entre las técnicas utilizadas. No hay diferencia significativa en la incidencia de óbitos en la primera semana y en el primero mes de pós-operatorio.
CONCLUSIONES: Los estudios retrospectivos generalmente cuestan poco y necesitan de menor tiempo cuando comparado con estudios controlados. Este estudio retrospectivo muestra que las técnicas de anestesia regional cursan con una baja incidencia de mortalidad en el primero mes y baja incidencia de complicaciones.
Femur fracture osteosynthesis and hip artroplasty are common procedures in elderly patients. Despite some consistent data regarding specific systems (lung, coagulation and GI tract), no single anesthetic technique has proved to be safer in geriatric patients submitted to major orthopedic surgeries. When compared to general anesthesia, regional anesthesia decreases mortality in approximately 30%1. Several randomized studies have associated regional anesthesia to a low mortality rate in 30 days 1. In addition, regional anesthesia decreased deep vein thrombosis in 44%, pulmonary embolism in 55%, blood transfusion in 50%, pneumonia in 39%, respiratory depression in 59%, acute myocardial infarction in 33% and renal failure in 43% 1. So it seems that regional anesthesia has globally reduced postoperative complications in studies with large surgical patients populations.
Subarachnoid injection of local anesthetic was first performed in 1898 2. In a single dose, it provides a potent blockade of fast onset, however with extension and duration difficult to estimate since several factors regulate local anesthetics kinetics in the CSF. Continuous spinal anesthesia was introduced in 1907 3, developed during the 40s 4,5 and clinically investigated in the 60s and 70s 6-9. Continuous spinal anesthesia consists of introducing a catheter in the subarachnoid space and maintaining blockade by repeated anesthetic injections. The possibility of fractionating local anesthetics dosage along time allows a fast onset with better blockade quality and less hemodynamic changes 10-12. Combined spinal-epidural anesthesia is a technique in which spinal anesthesia and epidural catheter are simultaneously used. This blockade has been used in major orthopedic surgeries 13-15.
This retrospective study aimed at comparing these three anesthetic techniques in major orthopedic surgeries throughout a 4-year period to determine their possible advantages and disadvantages in elderly patients.
Anesthetic records of 521 patients submitted to femur osteosynthesis and total or partial hip replacement under single shot spinal anesthesia, combined spinal-epidural block and continuous spinal anesthesia between January 1997 and December 2000 were selected and retrospectively analyzed.
Inclusion criteria (Chart I) were: patients aged above 60 years, not admitted to ICU, without preoperative vesical catheter, physical status ASA I or II, submitted to surgery within the first 24 hours after admission, with blockades performed in the left lateral position, not receiving low molecular weight heparin, spinal or epidural opioids, who received pre or postoperative analgesia with the 3 in 1 blockade and who, until the fracture, had a life compatible with age and without mental confusion. All anesthesias were performed by the authors.
No patient was premedicated. Monitoring in the operating room consisted of continuous ECG in CM5, non-invasive blood pressure and pulse oximetry. All patients had an upper limb vein punctured with an 18G venous catheter and a 2 L.min-1 oxygen catheter or Hudson mask installed. After venous puncture, patients were given intravenous midazolam (1.5 - 4.5 mg) and meperidine (10 - 30 mg). To place the patient in the blockade position (LLP), 10 to 30 mg intravenous ketamine were injected, or 3 in 1 blockade was performed with 40 ml of 0.25% bupivacaine. Postoperative analgesia was achieved with 40 ml of 0.25% bupivacaine through the 3 in 1 blockade as well, and was maintained by injections through a catheter placed in the inguinal perivascular space.
Group 1 - Single Shot Spinal Anesthesia (Simple Spinal)
Spinal puncture was paramedially performed at L2-L3 or L3-L4 interspace with the patient in the left lateral position, using 27G disposable Quincke needles (B. Braun, Meisungen, AG), with their bevels always parallel to dural fibers. After obtaining CSF, 15 mg of 0.5% isobaric bupivacaine were injected without barbotage, at a rate of 1 ml.15s-1. Patients were then immediately placed in the supine position (Table I). In case of failure, confirmed by lack of perineal sensitivity, a new puncture was performed and a lower dose of the same anesthetic drug was injected.
Group 2 - Combined Spinal-Epidural Block (CSEB)
With patients in the left lateral position, epidural puncture was paramedially performed at L2-L3 or L3-L4 interspace using the loss of resistance to air technique with an adequate single shot device (Espocan® B. Braun Meisungen AG). Then, a 27G spinal anesthesia needle was introduced through the Tuohy needle and, after CSF return, 0.5% isobaric bupivacaine was injected in a dose depending on patients height (Table I). Spinal needle was then removed and an epidural catheter was inserted. In the presence of pain or inadequate block level, 5 ml of 0.5% bupivacaine were injected through the epidural catheter, which was removed at the end of the surgery.
Group 3 - Continuous Spinal Anesthesia (Continuous Spinal)
Using the previously described technique 11, the epidural puncture was paramedially performed in the left lateral position at L2-L3 or L3-L4 interspace with an 18G Crawford needle. After that, dura was punctured with a Spinocath® device (B. Braun Meisungen AG) with a 27G needle and 22G catheter set. With the patient still in the puncture position, 5 to 10 mg of 0.5% isobaric bupivacaine were injected, depending on patients´ height, when they were immediately placed in the supine position. In case of pain or inadequate level, 2.5 mg of 0.5% bupivacaine were injected through the spinal catheter (Table I), which was removed at the end of surgery.
Sensory block level and motor block degree (modified Bromage scale, 0 = no blockade and 3 = total blockade) were tested at 5 to 20-minute intervals. Associated diseases and drugs in use were also recorded.
The following data were analyzed: age, gender, height, weight and ASA physical status. Anesthesia mishappenings, such as blockade failure, need to complement with general anesthesia, arterial hypotension and bradycardia, need for vasopressants or vesical catheter, mental confusion, blood transfusion and 1 week/ 1 month mortality were recorded.
Sedation was obtained with fractionated midazolam and meperidine doses.
All values are expressed in mean and SD. The following statistical tests were used: Kruskal-Wallis, analysis of variance, Bonferronis test and non-parametric Chi-square test, considering significant p < 0.05.
Three hundred patients´ records which complied with the inclusion criteria were studied, with 100 cases following each technique presented in table I. Mean bupivacaine dose was 15.30 mg in the Simple Spinal Group, 23.68 mg in the CSEB Group and 10.10 mg in the Continuous Spinal Group, with statistical significant differences (p < 0.01) between groups 1 and 2, 1 and 3, and 2 and 3.
Patients demographics data are shown in table II, with no statistical differences between groups in age, weight and gender. Group 2 patients were statistically shorter as compared to groups 1 and 3. Patients clinical conditions and drugs in use are shown in table III, with no significant differences between groups.
There were 3 failures in the Simple Spinal Group with the need for a new puncture. There were also 3 failures in the CSEB group and surgery was performed with more anesthetic being injected through the epidural catheter. There was no failure in the Continuous Spinal group. In 20 CSEB and 15 Continuous Spinal patients, an additional dose via catheter was needed to begin or complete the surgery. All patients were sedated with fractionated midazolam and meperidine doses, with no need for general anesthesia complementation.
Cephalad analgesic spread is shown in table IV, with significant differences (p < 0.01) between groups 1 and 2, 1 and 3, and 2 and 3. In the Simple Spinal group, 75% of patients showed a spread between T10 and T8; in the CSEB group, 77% of patients had it between T10 and T7 and in the Continuous Spinal group, 90% of patients presented a spread between T12 and T10. This last group showed therefore a more uniform spread of the anesthetic.
All patients had total motor block.
There were no significant differences in hypotension, bradycardia, paresthesia and blood transfusion. Nineteen patients presented postoperative mental confusion, with no significant difference between techniques (Table V).
There were also no significant differences in mortality in the first week and within 1 month after surgery.
The number of patients not studied or excluded from the study is high. Incomplete records may result in retrospective studies limitations 16.
This study has shown that for major orthopedic surgeries in elderly patients, continuous spinal anesthesia has some advantages over simple spinal or combined spinal-epidural anesthesia: less cephalad spread, lower incidence of arterial hypotension and less local anesthetic requirement.
Femur and hip fractures are major issues for health services. Incidence increases with age, with predominance of women due to association to osteoporosis. In our study, this was confirmed by the 62% presence of women in the groups.
Combined spinal-epidural and continuous spinal anesthesia patients received a lower initial isobaric bupivacaine dose as compared to single shot spinal anesthesia patients. Due to the presence of the catheter, which would allow dose increment if needed. The consequence was a 20% catheter complementation in the combined spinal-epidural block and a 15% complementation in the continuous spinal block with no need for general anesthesia association.
Sensory block level may be easily obtained and controlled with continuous spinal anesthesia, while a higher dose is needed when single shot spinal anesthesia or epidural anesthesia are used. Cardiocirculatory stability seen in all groups with the isobaric solution shows that there might be a dissociation between sensory and sympathetic blocks. Analgesia level with continuous spinal anesthesia remained two segments below single shot spinal anesthesia and 4 segments below combined spinal-epidural block.
Bromage scale is a motor block qualitative but not quantitative indicator. However, since all patients reached the highest lower limbs motor block degree after anesthetic injection, there was no need to correlate different degrees. An interesting advantage of all techniques for major orthopedic surgeries is the initial anesthetic injection in the subarachnoid space resulting in total motor block with low doses, which would be difficult to obtain with epidural anesthesia alone.
One of the major reasons for the preference for epidural blockade is the early and rapid hypotension caused by spinal anesthesia, but epidural anesthesia stability is purely historical 17. In our study, all patients received spinal local anesthetics, but the epidural additional dose given to the spinal-epidural group resulted in a higher incidence of hypotension as compared to other groups, with no statistical significance though. Blood pressure stability is a problem in elderly patients, regardless to the technique employed. However, the incidence of hypotension among our 300 patients was less than 10%.
An important finding of this study was the low incidence of urine retention requiring vesical catheter (3.6%). Urine retention is caused by peripheral and central neurogenic mechanisms interfering with micturition reflexes, including autonomic blockade, which takes three times longer to resolve than two segments regression time 18. In our study, bladder catheterization was needed when blockades had already disappeared in all patients. Only 11 of them needed a vesical catheter and this is important in the partial or total hip replacement context. Post-arthroplasty infection results in general in prosthesis rejection. Bacteremia may follow uretral instrumentation and the need for catheterization increases post-arthroplasty sepsis in 6.2% 19. For providing a lower blockade level with a lower local anesthetic dose, continuous spinal anesthesia group showed the lowest vesical catheter need requirement.
Postoperative mental confusion is a transient situation for the elderly and its etiology is not known. Different hip fracture studies were unable to correlate mental confusion to the anesthetic technique employed. There are several independent factors affecting postoperative delirium, including postoperative pain 16. Since regional anesthesia provides a better analgesia as compared to systemic techniques, it may be advantageous in decreasing postoperative mental confusion. Our patients received analgesia by the 3 in 1 blockade technique administered before or after spinal block 20. Mental confusion incidence was 6.3% and disappeared within 1 or 2 postoperative days. Although not achieving statistical significance, mental confusion was seen half the times with spinal anesthesia as compared to single shot spinal anesthesia and combined spinal-epidural block.
Regional anesthesia decreases mortality in approximately 30% when compared to general anesthesia 1. Regional anesthesia is associated to a low mortality rate within 30 days, when 75% of deaths are caused by pulmonary embolism, infection or heart disturbances 1. A recent study with 450 patients has shown a mortality rate of 3% within 14 postoperative days after spinal anesthesia, compared to 7% after general anesthesia 21. Our study has not compared mortality with general anesthesia, but has shown that regional anesthesia had virtually the same mortality rate (3.6%). Increased morbidity-mortality in elderly patients is explained by a decrease in patients basic organic functions. One study found a low mortality rate (1.38%) during the first postoperative days in patients above 65 years of age, but didn´t correlate it to the type of surgery 22. Similarly to vesical catheter need and arterial hypotension, mortality rates during the first week and the first month were two times lower with continuous spinal anesthesia as compared to single shot spinal anesthesia and combined spinal-epidural block.
Several papers have shown the benefits of regional anesthesia when it is extended to the postoperative period 20,23. Postoperative analgesia, however, is just one of the factors taken into account by morbidity-mortality studies. A study performed with postoperative lumbar plexus block (3 in 1) 20 has shown a better analgesia lasting for a mean time of 16 hours 20, and lower need for opioids 20 and vesical catheter, which might have contributed to the low mortality rate in one month (3.6%).
Prospective controlled studies provide more reliable results, but to establish whether regional anesthesia has some benefit on mortality, it would be necessary a sample size of 24,000 patients 24. In spite of the increased use of meta-analysis combining and evaluating data from different sources, they have some disadvantages 25. Retrospective studies in general cost less and take less time as compared to controlled studies, but may result in unreliable findings 26. Our study is a retrospective evaluation and one of the first papers in Brazil correlating regional anesthesia techniques to morbidity-mortality in elderly patients with hip fractures. Our results have shown a low mortality rate (3.6%) in the first month and a low complication rate with the three regional anesthesia techniques.
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Dr. Luiz Eduardo Imbelloni
Address: Av. Epitácio Pessoa, 2356/203 Lagoa
ZIP: 22471-000 City: Rio de Janeiro, RJ
Submitted for publication August 13, 2001
Accepted for publication November 1, 2001
* Received from Casa de Saúde Santa Maria e Clínica São Bernardo, Rio de Janeiro, RJ