Tanta Medical Journal

ORIGINAL ARTICLE
Year
: 2018  |  Volume : 46  |  Issue : 2  |  Page : 99--107

Single-shot spinal anesthesia with heavy bupivacaine in two regimens versus continuous spinal anesthesia in elderly patients undergoing hip surgery: a prospective randomized controlled study


Aliaa M.A.R Abdel Kader, Kamal E Ali Hekal, Yaser M Amr Ragheb, Amr A Magdy 
 Department of Anesthesia and Surgical Intensive Care, Faculty of Medicine, Tanta University, Tanta, Egypt

Correspondence Address:
Aliaa M.A.R Abdel Kader
Master Degree of Anesthesia and ICU Tanta University; Department of Anesthesia and Surgical Intensive Care, Faculty of Medicine, El-Garbia, El-Fateh Street, El-Naser with Bhary El-Masakn 12, Tanta University, Tanta
Egypt

Abstract

Background Elderly patients with hip fracture are a medical challenge. Spinal anesthesia (SA) is effective, rapid, has minimal effect on mental status, reduces blood loss, and thromboembolic complications. The continuous spinal anesthesia (CSA) produces more sensory–motor blockade with fewer hemodynamic effects. Intrathecal opioids can achieve successful SA using decreased doses of local anesthetics. Aim The aim of this study is to compare the safety and the efficacy of single-shot SA with heavy bupivacaine in two regimens versus continuous SA in elderly patients undergoing hip surgery. Patients and methods This study was carried out on 60 patients aged 65 years or older patents scheduled for hip surgery. Patients were randomized into three groups (n=20): group A SA with hyperbaric bupivacaine 7.5 mg, group B spinal fentanyl anesthesia (SFA) SA with hyperbaric bupivacaine 5 mg+25 μg fentanyl, and group C (CSA) with continuous SA. Heart rate (HR), mean arterial pressure (MAP), onset, duration, and the level of sensory block and onset, duration and score of motor block were recorded. Complications, amounts of fluids, and/or blood products and the use of vasopressors, total doses of bupivacaine, need for sedation, supplementation, and anesthetic failure were recorded. Assessment of pain was done using by visual analog score for 6 h postoperatively. Results MAP showed significant decrease in group A. The onset of sensory block and time to reach T10 showed significant increase in group C. Time of regression of sensory block T12 showed significant decrease in group C. The onset of motor block showed significant increase in group C. The duration of the motor block showed significant decrease in group C. Scores of motor block in the three groups show insignificant difference. Conclusion CSA had the advantage of being significantly hemodynamically stable and lower dose of local anesthetics and ephedrine than SA. Besides, intrathecal opioids improve the quality of spinal block.



How to cite this article:
Abdel Kader AM, Ali Hekal KE, Amr Ragheb YM, Magdy AA. Single-shot spinal anesthesia with heavy bupivacaine in two regimens versus continuous spinal anesthesia in elderly patients undergoing hip surgery: a prospective randomized controlled study.Tanta Med J 2018;46:99-107


How to cite this URL:
Abdel Kader AM, Ali Hekal KE, Amr Ragheb YM, Magdy AA. Single-shot spinal anesthesia with heavy bupivacaine in two regimens versus continuous spinal anesthesia in elderly patients undergoing hip surgery: a prospective randomized controlled study. Tanta Med J [serial online] 2018 [cited 2018 Nov 18 ];46:99-107
Available from: http://www.tdj.eg.net/text.asp?2018/46/2/99/244684


Full Text



 Introduction



Elderly patients with hip fracture remain a medical challenge for the anesthesiologist, mainly because of the frequent and numerous comorbidities encountered; moreover, the incidence of these comorbidities has increased during the past years [1].

No single anesthetic technique or agent appears to have universal advantage for the elderly surgical patient with regard to survival. Both general and regional anesthesia are associated with side effects in geriatric patients [2],[3].

Spinal anesthesia (SA) is a widely used anesthetic technique for lower limb surgery in the elderly. It is often preferred for its efficacy, rapidity, minimal effect on mental status, reduction of blood loss, and protection against thromboembolic complications [4]. However, risk of severe and prolonged hypotension is associated with SA due to the rapid extension of the sympathetic block, hindering cardiovascular adaptation and causing significant morbidity and mortality [5].

Many different techniques, such as intraperitoneal crystalloid and vasopressor administration, have been used to attenuate this complication [6]. However, rapid infusion of large amounts of intraperitoneal fluid may be detrimental to patients with cardiac dysfunction [7]. Moreover, ephedrine and vasopressors can lead to serious cardiac side effects (excessive hypertension or tachycardia).

The continuous spinal anesthesia (CSA) technique may offer several advantages over single-shot SA in patients undergoing extensive surgery of the lower part of the body especially in the elderly as there is a high prevalence of medical problems and a reduction in physiologic compensatory mechanisms [8], It has been reported to be more rapid in action, producing more pronounce sensory–motor blockade with fewer hemodynamic alterations and side effects by enabling the reduction and fractionation of the induction dose through a catheter [9].

However, CSA has been implicated in causing specific complications, such as infection, headache, or cauda equina syndrome [10].

Opioids and local anesthetics administered together intrathecally have a potent synergistic analgesic effect [11],[12]. Intrathecal opioids enhance analgesia from subtherapeutic doses of local anesthetics and make it possible to achieve successful SA using otherwise inadequate doses of local anesthetics [13].

 Patients and methods



After approval by the local ethics committee, 60 patients aged 65 years or older scheduled for hip surgery in the Orthopedic Department of Tanta University Hospital provided written informed consent and received an explanation to the purpose of the study. Research results will be only used for scientific purposes. This prospective, randomized, controlled clinical study was approved by both the Institutional and the Regional Ethics Committees. Any unexpected risks that appeared during the course of research were clarified to the participants and the ethics committee in time. The patients who refused, uncooperative patients, with coagulation disorders, with low, fixed cardiac output, with localized back sepsis, or with a history of allergy to any of the drugs planned for administration were excluded from the study.

Justification of sample size

The sample size calculation was performed using EpI-Info 2002 software statistical package designed by the WHO and by Centers for Disease Control and Prevention.

The sample size was calculated based on the following considerations:95% level of significance.80% power of the study.

Patients were nonblindly randomized according to a computer-generated schedule followed by preparation of coded envelops to three groups:

Group A (SA) received SA with hyperbaric bupivacaine 7.5 mg (n=20).

Group B (SFA) received SA with hyperbaric bupivacaine 5 mg+25 μg fentanyl (n=20).

Group C (CSA) received continuous SA (n=20).

Preoperative assessment was done by history taking, clinical examination, and laboratory investigations (complete blood count, liver function, renal function, and bleeding and coagulation profile). On arrival at the operation theater, standard monitoring in the form of a 3-lead ECG monitor, pulse oximetry, and an automated noninvasive arterial blood pressure monitor were applied. Baseline systolic, diastolic, and mean arterial pressures were recorded. A good venous access was secured with 20-G cannula. Intravenous infusion of 8 ml/kg of Lactated Ringer’s solution for more than 30 min was given.

SA was performed in the sitting position. After standard preparation and draping, one of the L4–L5 or L5–S1 interspaces was chosen and the overlying skin was anesthetized by local infiltration with 3–5 ml of lidocaine 2% using a 27 G needle. Hyperbaric bupivacaine was used for all cases. For groups A and B, subarachnoid puncture was performed in the sitting position with a 22-G cutting needle.

In group A, injection of 7.5 mg (1.5 ml) of hyperbaric bupivacaine was given for more than 10–15 s. After completion of the injection, the patients returned to the supine position.

For group B, an injection of 5 mg (1 ml) of hyperbaric bupivacaine plus 25 μg (0.5 ml) fentanyl was given, total volume (1.5 ml) made over 10–15 s. After completion of the injection, the patients returned to the supine position.

For group C, lumbar puncture performed with a 18-G Tuohy needle (B-Brown) at the L4–L5 interspace or L5–S1 after obtaining free flow of CSF 3 cm of a 20-G catheter was introduced cephalad through the needle. An initial dose of 5 mg (1 ml) of hyperbaric bupivacaine was injected through the catheter for more than 10–15 s. After completion of injection the patients returned to the supine position. Successive injections of 1 mg hyperbaric bupivacaine were performed every 10 min or as needed to establish adequate levels of anesthesia.

Routine intraoperative monitoring (ECG and oxygen saturation and arterial pressure was measured every 5 min during surgery and a urinary catheter was inserted for monitoring the amount of urine output.

Bradycardia if decreased by 20% or more and severe bradycardia if decreased by 30% or more from the heart rate baseline were treated with atropine 0.01–0.02 m/kg.

Hypotension was defined as a decrease of more than 20% from the baseline systolic arterial blood pressure (SAP). Severe hypotension was defined as a decrease in SAP by more than 30% of the baseline value. Hypotension was treated with intravenous boluses of ephedrine 6 mg repeated every 3 min.

If, initially, signs of inadequate anesthesia (e.g. reaction to skin incision) are present, general anesthesia was given and this was recorded and the case was designed as ‘failed spinal block’. Moreover, if the surgical procedure outlasted the duration of the block, supplementary intrathecal anesthesia was given and recorded.

Any intraoperative episodes of nausea, vomiting, pruritus and/or shivering were noted.

After surgery was completed, the catheter was removed after injection of 0.2 ml of heavy bupivacaine for group C and all patients received intravenous paracetamol 1 g every 8 h and were transferred to the recovery area for monitoring of vital signs and regression of the block.

Pethidine 20 mg, intraperitoneal, bolus offered for the patients whose postoperative pain score (visual analog score) was more than 4. Postoperatively the patients were followed up over the phone for 2 weeks to identify complaints related to anesthesia.

Measurements

Demographic and surgical data (age, sex, weight, height, BMI, American society of anestheologist (ASA) classification, and type of surgery).Hemodynamic data:Heart rate: at baseline and 5, 10, 15, and 30 min and 1, 2, and 3 h during surgery.Arterial blood pressure: at baseline and 5, 10, 15, 30 min and 1, 2, 3 h during surgery.Onset, duration, and the level of sensory block.The upper level of analgesia was determined by attempting to elicit grimacing or acknowledgment of pain to bilateral pin prick at each dermatome at 5, 15, 25 min.The onset from the end of injection to the beginning of block.Duration of sensory block: defined as the time interval from the establishment of complete sensory block to two-segment regression of sensory block by the pinprick method from the end of onset to recovery from block. The level of block by pinprick test was at T10.Onset, duration, and score of motor block:The onset from the end of injection to the start of block.Duration from end of onset to recovery from block.Score by the Bromage scale.0-no paralysis=full flexion of knee and foot.Hip flexion with extended leg=just able to move knees.Knee flexion blocked=just able to move feet only.Complete motor block=total paralysis.The number of hypotensive episodes and other complications such as nausea, vomiting, shivering, pruritus, respiratory depression.The total amounts of fluids and/or blood products and the use of vasopressors (e.g. ephedrine) will be recorded.Total injected doses of bupivacaine.Need for sedation, supplementation, and anesthetic failure or the need for general anesthesia.Assessment of pain by visual analog score for 6h postoperatively.Statistical presentation and analysis of the present study was conducted, using the mean, SD, and χ2-test by SPSS. A P value of less than 0.05 was considered significant.

 Results



Regarding the demographic data as age, sex, weight, there was no significant difference ([Table 1] and [Table 2]).{Table 1}{Table 2}

A comparison of mean arterial pressure (MAP) (mmHg) in the three studied groups ([Figure 1]) has shown that the mean arterial blood pressure showed no significant difference in the baseline period (P=0.098). But there were significant difference at 5, 10, 15, 30 min and 1, 2, 3 h after injection of local anesthetics, which was more of a decrease in mean arterial blood pressure in group SA when compared with the other groups.{Figure 1}

Comparison between the onset of sensory block in the groups ([Figure 2]) shows significant difference in onset which was longer in group CSA when compared with the other groups (P=0.001).{Figure 2}

Comparison between time to reach T10 of sensory block between the groups ([Figure 2]) shows significant difference in duration which is more longer in group CSA when compared with the other groups (P=0.001).

Comparison between time of regression of sensory block T12 of sensory block between the groups ([Figure 2]) shows significant difference in duration which is more shorter in group CSA when compared with the other groups (P=0.001).

Comparison between onset of motor block in the three groups ([Figure 3]) shows significant increase in group CSA when compared with the other groups (P=0.001).{Figure 3}

Comparison between duration of motor block in the three groups ([Figure 3]) shows significant decrease in group CSA when compared with the other groups (P=0.001).

Comparison between score of motor block in the three groups ([Figure 4]) shows insignificant difference when compared with each other (P=0.503).{Figure 4}

[Figure 5] show comparison.10% of the patients received atropine in group SA and no patient in the other two groups with P=0.129 showed significance.60% of the patients developed hypotension in group SA and 15% in group SFA and 0% that showed significant decrease in blood pressure in group CSA when compared with the other two groups with P=0.001.15% of patients developed severe hypotension in group SA and 0% in group SFA and 0% that show significant decrease in blood pressure in group CSA when compared to the two other groups with P=0.045.One patient in group CSA needed general anesthesia due to failed CSA and no patients needed it in the other two groups.Two patients in group CSA needed intraoperative supplement through the catheter to complete surgery.{Figure 5}

[Figure 6] show comparison.10% of patients had nausea in group SA and no patient in the other two groups with P=0.129 showing no significance.10% of patients had pruritis in group SFA and no patient in the other two groups with P=0.129 showing no significance.10% of patients had temporary confusion in group SA and no patient in the other two groups with P=0.129 showing no significance.No patients in the three groups had post dural puncture headache (PDPH) or respiratory depression.25% of patients had pain in group SA and 0% in group SFA and 0% showed significance in group SA when compared with the two other groups with P=0.005.{Figure 6}

 Discussion



Hip fracture is a common and critical event for elderly patients [14]. General and regional anesthesia are associated with side effects in geriatric patients [2],[15],[16].

Although regional anesthesia might have benefits over general anesthesia [17], hemodynamic stability may be impaired and can lead to myocardial ischemia. A smaller dose of local anesthetic reduces the severity and incidence of hypotension during SA [18],[19]. These findings are of particular interest in elderly patients with high risk of sympathectomy-induced hypotension.

CSA is a technique for producing and maintaining SA with smaller doses of local anesthetic that are injected intermittently into the subarachnoid space via an indwelling catheter. It has several advantages over epidural anesthesia [20] as the administration of local anesthetics in small incremental doses titrated to the individual patient’s needs, reduced requirements of local anesthetics and thus decreased systemic toxic effects, ensured cardiovascular stability, extended anesthesia by supplemental application of spinal local analgesics when surgery is unexpectedly extended [20],[21].

The present study compared the changes in heart rate and mean arterial blood pressure. Onset, level, and the duration of sensory and motor block, the number of hypotensive episodes, as well as the total amounts of fluids and/or blood products and the use of vasopressors (e.g. ephedrine) were recorded. Postoperative complications such as nausea, vomiting, respiratory depression, confusion, and PDPH were also recorded.

As regards the hemodynamic and the total amount of vasopressors, hypotension was defined as a decrease of more than 20% from baseline SAP; severe hypotension was defined as a decrease in SAP of more than 30% of baseline value in order to allow early treatment to avoid severe hypotension in our elderly patients.

The present study found that the incidence of hypotension and severe hypotension was significantly different between three groups. In the SA group, nearly 60% experienced hypotension and nearly 15% experienced severe hypotension. In the SFA group nearly 15% experienced hypotension, in the CSA group no patient experienced an episode of hypotension or severe hypotension.

These results could be explained as in the CSA group; the present study used lower doses of bupivacaine at induction of anesthesia and titration of small doses of bupivacaine to maintain the anesthesia which allowed slower onset of segmental block in this group. This allowed the cardiovascular system to adapt more easily than when the sympathetic block appears abruptly as with single-shot SA.

In agreement with our study Lairez et al. [22], who assessed the cardiovascular effects induced by a single injection of a low-dose SA during elective surgery by using transthoracic echocardiography and compared these effects in patients older and younger than 70 years of age, found that hypotension is more frequent among elderly patients, even after low-dose SA. The known age-related changes in cardiovascular performance, such as impaired myocardial relaxation and decreased systolic function could be responsible for the decrease in cardiac output and SVR seen in these patients.

Moreover, in a study performed by Lairez et al. [22] it has been found that lowering local anesthetics dose could decrease the incidence of arterial hypotension, while maintaining the quality of surgical anesthesia, and their results resemble our results as 66 patients over the age of 65 years, with hip fracture scheduled for surgical repair, were assigned to two groups (control group) received 7.5 mg hyperbaric bupivacaine, and the study group received 3.75 mg hyperbaric bupivacaine. Arterial hypotension incidence was lower in the study group (at 5, 10, and 15 min determinations), and a lower amount of vasopressor drugs was needed (mean accumulated ephedrine dose of 1.6 versus 8.7 mg in the control group (P<0.002).

As regards the amount of total administrated vasopressors (ephedrine) the mean dose of ephedrine was significantly larger in the SA group than in the CSA group (P<0.0001). Nearly 75% of SA patients required ephedrine (3 mg to >30 mg) to maintain pressure; no patients in the CSA group required ephedrine and only three patients in the SFA group received ephedrine.

In agreement with our study, Favarel-Garrigues et al. [23] compared hemodynamic changes between CSA and single-dose SA on 60 elderly patients older than 70 years who underwent hip surgeries. They found that the decrease in mean arterial blood pressure in CSA was 19.9±1.6% and in single-dose SA it was 40.2±1.9%, which show more decrease in mean arterial blood pressure in single-dose SA and hence CSA is more hemodynamically stable which supports our study. The mean dose of ephedrine was significantly less in the CSA group (1.8±0.7 mg, administered to only 37% of patients) than in the other group (19.4±3.3 mg administered to all patients, P<0.0001).

As against our study, Pitkanen et al. [24] compared hemodynamic changes between CSA and single-dose SA with plain bupivacaine on 40 elderly patients scheduled for hip or knee surgeries. The mean decrease in mean arterial blood pressure in CSA was 17 mmHg and in single-dose SA it was 21 mmHg. They found that both groups were quite similar regarding hemodynamic stability.

Opioids and local anesthetics administered together intrathecally have a potent synergistic effect, improving the quality of intraoperative and postoperative analgesia A combination of these agents allows for a reduction in the dose of both classes of drugs, lessening the likelihood of side effects attributable to each, which is particularly beneficial for geriatric patients.

Intrathecal opioids enhance analgesia from the subtherapeutic dose of local anesthetic and make it possible to achieve successful SA using otherwise inadequate doses of local anesthetics [25]. In the present study, group SFA also had little hemodynamic stability than group SA.

In agreement with our study, Malcolmson et al. [26] compared two doses of bupivacaine plus fentanyl and found that in elderly patients low-dose bupivacaine/fentanyl (4 mg bupivacaine plus 20 µg fentanyl) SA provides greater hemodynamic stability compared with standard dose (10–14 mg bupivacaine plus 10–20 µg fentanyl) SA during surgical repair of hip fractures which support our study.

Moreover, in a study performed by Olofsson et al. [15] it has been found that a reduced dose of hyperbaric bupivacaine (7.5 mg) in combination with sufentanil (5 μg) provides reliable SA for the repair of hip fracture in aged patients with few events of hypotension and little need for vasopressor support of blood pressure when compared with 15 mg bupivacaine.

The present study found that intrathecal opioids improve the quality of sensory and motor block without increasing the sympathetic block. As regards sensory and motor block characteristics, the present study found that patients in group SFA, who received 5 mg bupivacaine plus 25 μg fentanyl, had longer duration of sensory and motor block.

In agreement with the present study, Kim et al. [27] compared fentanyl 25 μg bupivacaine 0.5% and sufentanil 5 μg bupivacaine 0.25% intrathecally for TURP in elderly patients and concluded that low-dose diluted bupivacaine with fentanyl 25 μg or sufentanil 5 μg can provide adequate anesthesia without hemodynamic instability for TURP in elderly patients.

Kim et al. [28] who evaluated the effect of 10 μg of fentanyl to 10 mg bupivacaine on sensory and motor block and side effects in 36 patients undergoing urologic surgery concluded that intrathecal small-dose fentanyl (10 μg on bupivacaine spinal blockade) prolonged the duration of sensory block and did not augment side effects and provide reliable anesthesia for urologic surgery.

In the present study (as regards onset, level, and the duration of motor and sensory block), the onset of both motor and sensory block is little longer in group CSA.

However, this is of minor clinical importance as no patients in the three groups need additional sedation and the presence of catheter provides any supplementation when needed.

In agreement with our study Biboulet et al. [29] assessed the predictability of 5 mg bupivacaine to give a T10 sensory level when injected subarachnoid in the elderly. They assessed 5 mg plain bupivacaine and 5 mg hyperbaric bupivacaine in 65 patients aged 75 years or more, scheduled to undergo elective hip surgery. They found that after 20 min, the mean sensory level was T8.8±3.2 in the isobaric group and T7.2±4.3 in the hyperbaric group without significant difference. It has been concluded that 5 mg bupivacaine is too high a dose in the elderly to limit the sensory blockade at T10 and avoid hypotension. In elderly patients, this dose allowed surgery to be performed, provided that the sensory level reached T10. When the initial dose only affects lumbar dermatomes, a caudal direction of the catheter must be evoked, and changing position must be preferred to incremental injections to reach thoracic levels.

As regards the failure rate, experimentally, injection through an intrathecal catheter appears to be a critical factor in influencing the distribution of local anesthetic in the subarachnoid space [30]. In some studies, the use of intrathecal catheters has led to technical difficulties, with a significant rate of failure [31]. The use of larger catheters may reduce this rate and avoids slow injection through high-resistance microcatheters which has been implicated as a possible cause.

In the present study, the incidence of failure in the CSA group (5%) recognized before the surgical incision and general anesthesia administrated as a sensory block was too low in spite of incremental doses with the patient in the horizontal position, an unintentional sacral placement of the catheter was proved radiologically.

However, the incidence of failure in CSA is low, in agreement with our study Sutter et al. [32] compared CSA with continuous epidural anesthesia for lower limb orthopedic surgery in the elderly. They analyzed anesthetic records of 457 patients who received CSA and 274 who received continuous epidural anesthesia over a 5-year period. The patients who had CSA were at a higher anesthetic risk (ASA 3–4, 76% as compared with 37%, P<0.001), but the incidence of failures was significantly lower (1.7%, as compared with 9%, P<0.001) and fewer patients showed a decrease in mean arterial pressure of more than 30% (44%, as compared with 65%, P<0.001) and/or received vasopressors (65%, as compared with 77%, P<0.01). Their data showed that CSA to be more reliable and to provide better cardiovascular stability which support our study.

As regards PDPH, in the present study, no patient had this complication in the three studied groups. The old fear that the large-bore needle used, 16–18 G, would result in an unacceptably high incidence of PDPH beginning to decrease especially in the elderly. However, little is known about the incidence of PDPH after CSA. No prospective studies have been performed, but the few retrospective ones that have been published suggest that the incidence is low.

In agreement with our study, Mazze et al. [33] have evaluated the incidence of PDPH associated with CSA in 200 male patients (mean age 65 years) who received SA in one of three ways with an 18 G Tuohy-Schliff needle/20 G catheter combination, with a newly developed 20/24 G catheter combination and with a 22 G. Every patient was followed up for 7 days postoperatively. It has been concluded that the incidence of PDPH associated with CSA is acceptable in appropriate clinical circumstances, but large initial doses of local anesthetic should not be administered.

 Conclusion



CSA produced efficient block compared with single-shot SA in elderly patients who underwent hip surgery. Also, intrathecal opioid improves the quality of spinal block regarding the duration of sensory and motor block.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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