A comparative study-efficacy and safety of combined spinal epidural anesthesia versus spinal anesthesia in high-risk geriatric patients for surgeries around the hip joint.

CONTEXT: Combined spinal epidural anesthesia (CSEA) has a significant advantage by enabling the use of low dose intrathecal local anesthetic, with knowledge that the epidural catheter may be used to extend the block as necessary. CSEA is useful in high-risk geriatric patients by providing greater hemodynamic stability. AIM: This study is designed to compare the clinical effects of CSEA versus spinal anesthesia in high-risk geriatric patients undergoing surgeries around the hip joint.
MATERIALS AND METHODS: Sixty patients aged >65 years, American Society of Anaesthesiology III and IV were randomly allocated into two equal groups. Group A (n = 30) received CSEA with 1 ml (5 mg) of 0.5% hyperbaric bupivacaine with 25 μg fentanyl through spinal route, and the expected incompleteness of spinal block was managed with small incremental dose of 0.5% isobaric bupivacaine through epidural catheter, 1-1.5 ml for every unblocked segment to achieve T10 sensory level. Group B (n = 30) received spinal anesthesia with 2.5 ml (12.5 mg) of 0.5% hyperbaric bupivacaine and 25 μg fentanyl. RESULT: Both the groups showed rapid onset, excellent analgesia and good quality motor block. Group A showed a significantly less incidence of hypotension (P < 0.01) along with the provision of prolonging analgesia as compared to Group B.
CONCLUSION: CSEA is a safe, effective, reliable technique with better hemodynamic stability along with the provision of prolonging analgesia compared to spinal anesthesia for high-risk geriatric patients undergoing surgeries around the hip joint.

RCT Entities:   Population Interventions Outcomes

INTRODUCTION

Hip surgeries are usually performed in elderly people. A feature of this population is a high prevalence of preoperative medical problems and often need stabilization before surgery. Both regional anesthesia and general anesthesia can be used for hip surgeries. Preoperative hypoxemia frequently occurs in hip fracture patients due to fat embolism or prolonged immobilization in the supine position.[1] The incidence of deep vein thrombosis, hypoxemia, pulmonary complications, intraoperative blood loss and postoperative mental confusion, have been significantly reduced in regional anesthesia as compared to general anesthesia.[234] Hence, regional anesthesia is widely used in geriatric, orthopedic surgery. Surgical repair of hip fracture and total hip arthroplasty are primarily performed on elderly patients. Combined spinal epidural, a single segment, needle through needle technique is reliable and has gained popularity in modern anesthesia practice. The block in combined spinal epidural anesthesia (CSEA) results from a relatively low dose of the spinal local anesthetic, followed by the epidural drug which help to increase the subarachnoid block to desired level.[5] It is now being used in elderly high-risk patients for surgery with good results. With CSEA the advantages of both spinal and epidural anesthesia can be obtained avoiding many of the side effects of spinal anesthesia (acute fall in blood pressure, unable to prolong analgesia) and disadvantages of epidural anesthesia (delayed onset and inadequate motor blockade). Recently, the combined lumbar plexus and sciatic nerve block techniques have been tried, especially for high-risk patients of hip fracture surgeries.[6]

Aim

This study is designed to compare the clinical effects of CSEA versus spinal anesthesia in high-risk geriatric patients undergoing major surgeries around hip joint.

MATERIALS AND METHODS

It was a prospective randomized comparative study conducted between July 2013 and June 2014. After obtaining approval from the Institution Ethical Committee and informed written consent, 60 patients aged >65 years, highest being 93 years, of both sexes, belonging to American Society of Anaesthesiology (ASA) physical status III and IV, posted for major orthopedic surgical procedures involving hip joint were included in the study. Patients with the absolute contraindication for regional anesthesia were excluded. The patients were randomly allocated into two equal groups by a sealed envelope technique. Group A received CSEA, whereas Group B received spinal anesthesia. All patients had standard monitoring like electrocardiogram, noninvasive blood pressure, pulse oximetry and invasive monitoring such as central venous pressure, where necessary. Intravenous (IV) line with 18-gauge IV cannula was secured and a preload of 500 ml of normal saline was given to every patient before starting the procedure. The patients were supported in sitting posture on a horizontal table, by an assistant. The lumbar area was prepared aseptically and draped. The inter vertebral space at L3-L4 was identified. The prick point was infiltrated with 2 ml of 2% lignocaine. Group A (n = 30) received CSEA with 1 ml of 0.5% hyperbaric bupivacaine and 25 μg fentanyl through 27-gauge Whitacre spinal needle, which was introduced through a 18-gauge Tuohy needle in the epidural space. Identification of the epidural space was done by using loss of resistance technique. The spinal needle was withdrawn after injection of the drug into cerebrospinal fluid (CSF), 18-gauge epidural catheter was then inserted and secured. The patient was then placed in supine position slowly.

Group B (n = 30) received spinal anesthesia with 2.5 ml of 0.5% hyperbaric bupivacaine and 25 μg fentanyl through 25-gauge Quincke–Babcock spinal needle in sitting a position. They were made supine slowly for gradual onset of blockade. Sensory changes were recorded bilaterally after 10 min by assessing changes in pin prick sensation by use of a safety pin protruding 2 mm through a guard (graded according to Gromley and Hill [Normal sensation = 0, blunted sensation = 1, no sensation = 2]). In Group A, 1.0–1.5 ml of 0.5% isobaric bupivacaine was given for every unblocked segment through epidural route to extend the block to T10.

The degree of motor block of lower limbs was assessed bilaterally using modified Bromage Scale (0 = no motor block, 1 = can flex knee, move foot, but cannot raise leg, 2 = can move foot only, 3 = cannot move foot or knee).

The following variables were monitored and recorded throughout the surgical procedure:

Onset and level of sensory block

Degree of motor block

Hemodynamic variables such as mean arterial pressure and heart rate

Total dose of epidural bupivacaine required to establish desired level of block and to prolong block

Assessment of quality of block by patients

Assessment by surgeon

Duration of analgesia.

If systolic blood pressure was <90 mm of Hg, small incremental dose of ephedrine hydrochloride, 6 mg IV was administered. Bradycardia, which was defined as heart rate <60/min was treated with 0.6 mg of atropine IV. All patients received 4l/min of oxygen through a disposable face mask intraoperatively. In Group A, to prolong anesthesia, all patients received first epidural top up 1½–2 h after the commencement of surgery depending on the level of regression. Any intraoperative and postoperative side effects (nausea, vomiting, retching, rigor) during first 24 h were recorded. Blood loss >15% was managed with transfusion of properly grouped and cross matched blood in both the groups. After the operation, all the patients were shifted to postanesthesia care unit (PACU). Patients in Group A received 10 ml of 0.125% bupivacaine through the epidural catheter and Group B received parenteral opioids (tramadol 50–100 mg slow IV) on demand. Close monitoring of vital parameters continued throughout the stay in PACU. Statistical analysis was done. Chi-square test was used where applicable, P < 0.05 was considered to be significant.

RESULTS

Table 1 shows the demographic profile of the patients in two groups. Both the groups were comparable according to age, sex, body weight, height and type of surgery.

Table 1

Demographic data

Table 2 shows neural block assessment between the two groups. The highest level of sensory block was T10 in Group A, whereas the highest level of sensory block in Group B was T6. All patients achieved the maximum degree of motor block (modified Bromage scale 3) in both the groups. Onset of sensory block was rapid in both the groups but duration was prolonged in Group A (CSEA) by the epidural drug, whereas, this facility could not be obtained in Group B spinal anesthesia patients.

Table 2

Neural block assessment

Table 3 shows Group A had much less incidence of hypotension compared to Group B, the result was highly significant, P < 0.01.

Table 3

Incidence of hypotension and bradycardia

DISCUSSION

American Society of Anaesthesiology physical scale status is commonly used to classify the preoperative status of the hip fracture patients. Hamlet et al.[7] reported that 3 years mortality was significantly less for ASA I and II patients (23%) than for ASA III, IV, and V patients (39%). Several studies have shown that analgesia levels obtained after subarachnoid injection of hyperbaric local anesthetic solution are approximately 3–4 spinal segments higher in elderly compared with young adult patients.[89] Possible reasons include decreased leakage of local anesthetic through intervertebral foramina, decreased compliance of the epidural space in elderly resulting in greater spread or an increased sensitivity of the nerves in elderly.[10] Precipitous arterial hypotension due to high levels of sympathetic block remains a common and acute problem associated with spinal anesthesia in geriatric patients. Despite prophylactic measures such as fluid preload, it may be difficult to maintain a near normal blood pressure in these patients.

To reduce the incidence and severity of hypotension, a combined spinal epidural technique has been described in which low dose intrathecal local anesthetic is used and epidural catheter is used to extend the block as necessary in an attempt to reduce hypotension. The onset of block is not delayed by this method, but at the same time adequate level of sensory block is obtained. The CSEA is particularly advantageous in high-risk geriatric patients where gradual onset of sympathetic block is desirable to reduce hemodynamic side effects.[11]

It has been a common practice now to add opioid additives to local anesthetics to reinforce the spinal block and at the same time to reduce the dose. We have used 25 μg of fentanyl to local anesthetic bupivacaine in both the groups with an idea that fentanyl can convert an inadequate dose of local anesthetic to an adequate dose without prolonging the motor block.[12] In Group B (spinal anesthesia group) 2.5 ml (12.5 mg) of 0.5% hyperbaric bupivacaine with fentanyl 25 μg produced analgesia for an average of 180 min. In Group A, all patients electively received first top up dose 1½–2 h after commencement of surgery depending on the number of dermatomal regression in order to prolong the duration of surgical analgesia. We found only 6.67% (2/30) of our patients in Group A suffered hypotension and required vasopressor (ephedrine 6 mg) single dose to maintain systolic arterial blood pressure to 100 mmHg, whereas in Group B 66.67% (20/30) suffered hypotension and required vasopressor (ephedrine 6 mg) single dose, 40% (8/20) of them required two incremental doses of vasopressor to maintain systolic blood pressure to desired level. Both groups had complete analgesia, excellent muscle relaxation, rapid onset but provision of prolonged analgesia through the epidural catheter was facilitated with CSEA with no systemic side effects. In our study, the difference in the incidence of hypotension and bradycardia and other important variables between the groups was significant [Figures 1 and 2]. In Group A the incidence of hypotension and bradycardia was 6.67% and 6.67% respectively whereas in Group B it was 66.7% and 30% respectively [Table 4]. The block in CSEA resulted from a relatively low dose of the local anesthetic through spinal route followed by epidural drug which help to increase the subarachnoid block to desired level.

Figure 1

Changes in mean arterial pressure in both groups

Figure 2

Changes in mean heart rate in both groups

Table 4

Comparison of hypotension and bradycardia among two groups

Many considerations have been given as to how epidural top up works after a spinal anesthesia in CSEA:[13]

Continuing spread of initial subarachnoid block

Existence of sub clinical analgesia at a higher level, which is enhanced and becomes evident by perineural transdural spread of epidural local anesthetic

Leakage of epidural local anesthetic through the dural hole in the subarachnoid space

Compression of the theca by the epidurally injected volume of local anesthetic (or even saline) solution resulting in a “squeezing” of CSF and more extensive spread of spinal, local anesthetic.

In spite of rapid extension of CSEA block, very low incidence of hypotension was seen which was significantly less than spinal block. Very few patients of both the groups complained of intraoperative side effects like nausea, vomiting and shivering. The result was not significant.

CONCLUSION

Combined spinal epidural technique is effective and safe, produces stable hemodynamics and provision of prolonging analgesia with low dose intrathecal local anesthetic as compared to spinal anesthesia in geriatric patients undergoing major surgeries involving the hip joint.