Duration Of Spinal Anesthesia Research Articles

Comparison of Duration of Spinal Anesthesia with Lidocaine or Lidocaine plus Epinephrine between Addicts and Non-addicts.

Duration of spinal anesthesia depends on the type of anesthetic agent, dosage and additive materials such as epinephrine, ephedrine and opioid. We compared the duration of spinal anesthesia with lidocaine 5% with or without epinephrine in addict and non-addict patients undergoing inferior limb fracture surgery. This single blinded randomized clinical trial was performed on 201 males (height ranged 150-180 cm) who referred to the Shahid Bahonar Hospital of Kerman for the inferior limb fracture. Their physical class was matched to the American association standard class 1 and 2, and they were appropriate candidates for the spinal anesthesia. The addict or non-addict groups were each divided into two subgroups. 75 mg of 5% lidocaine was prescribed for one subgroup, and the other subgroup received 75 mg of 5% lidocaine plus 0.2 mg epinephrine. The level of primary anesthesia was elevated to T6. Duration of returning to the 4 primary sensory levels was measured since baseline. A significant increase in the duration of anesthesia level in both addict and non-addict patients receiving lidocaine plus epinephrine was observed compared to the subgroups receiving lidocaine alone (P < 0.01). Duration of decrease in sensory level in addict subgroups receiving lidocaine or lidocaine plus epinephrine was lower compared to non-addict patients (P < 0.001). In addict subgroup receiving lidocaine alone, a significant decrease was observed in the time needed for decrease in sensory level (P < 0.01). According to the results of this study, regardless of the anesthetic agent being used, duration of spinal anesthesia was shorter in addict patients compared to non-addict ones. Addition of epinephrine to lidocaine 5% increased the duration of spinal anesthesia in both addict and non-addict patients.

Intrathecal chlorprothixene, cis(z)-flupenthixol, chlorpromazine and fluphenazine for prolonged spinal blockades of sensory and motor functions in rats

The aim of this study was to examine whether thioxanthine-type antipsychotics (chlorprothixene and cis(z)-flupenthixol) and phenothiazine-type antipsychotics (chlorpromazine and fluphenazine) produced spinal anesthesia. Using a rat model of intrathecal injection, we evaluated spinal anesthesia of antipsychotic drugs (chlorprothixene, cis(z)-flupenthixol, chlorpromazine, and fluphenazine) and bupivacaine, a known local anesthetic. At a same dose of 2.31μmol/kg, chlorprothixene had the most potent spinal blockades (P<0.001) and the longest duration of action (P<0.001) of motor function and nociception among those antipsychotic drugs. On the 50% effective dose (ED50) basis, the ranks of potencies were chlorprothixene=bupivacaine>cis(z)-flupenthixol>chlorpromazine>fluphenazine (P<0.01 for the differences) in dose–response studies. At an equianesthetic basis (ED25, ED50, and ED75), the spinal block duration caused by chlorprothixene, cis(z)-flupenthixol, chlorpromazine or fluphenazine was longer than that caused by bupivacaine (P<0.05). These results showed that chlorprothixene produced a similar potency and longer duration of spinal anesthesia than did bupivacaine, whereas several other antipsychotics produced less potency than did bupivacaine.

The Effect of Body Mass Index on Spinal Anaesthesia for Total Knee Replacement Arthroplasty: A Dose-response Study

The aim of this study was to compare the duration of spinal anaesthesia in obese and non-obese subjects. We also quantified the effect of body mass index (BMI) on spinal anaesthesia by comparing the median effective dose (ED50) of intrathecal hyperbaric bupivacaine required in the two cohorts. One hundred and eight patients undergoing elective total knee replacement arthroplasty under combined spinal-epidural anaesthesia were enrolled as a non-obese group (BMI <27.5 kg/m(2)) or obese (O) group (BMI ≥ 27.5 kg/m(2)). Each group was further subdivided by bupivacaine doses of 6, 7, 8, 9, 10 or 11 mg, respectively. Anaesthesia was deemed successful if a bilateral T12 sensory block occurred within 15 minutes of intrathecal drug administration and epidural supplementation was not required. The ED50 for successful anaesthesia and that for successful block of tourniquet pain were determined separately by probit regression analysis. Although the analgesic duration was prolonged with higher doses of bupivacaine in group O, the ED50 for successful anaesthesia did not differ between groups. However, the incidence of tourniquet pain was lower in group O and the ED50 for block of tourniquet pain was less in group O. This study suggests that bupivacaine dose reduction is not necessary, but analgesic duration may be prolonged in patients with higher BMI. These patients require careful consideration of spinal anaesthetic dose to minimise the risk of unnecessary prolongation of anaesthesia.

A comparative study on the effects of intrathecal morphine added to levobupivacaine for spinal anesthesia

In this prospective, randomized, double-blind, controlled study, we investigated the sensory, motor, and analgesic block characteristics oftwo diferent doses of morphine compared with saline when added to 0.5 percent levobupivacaine. Prospective, randomized, double-blinded, controlled study. University hospital. PATIENTS, PARTICIPANTS, INTERVENTIONS: One hundred and twelve ASA I or II adult patients undergoing cesarean section with combined-spinal epidural anesthesia (CSEA) were randomly allocated to receive 0.5 mL of0.9 percent sodium chloride in group S, 0.1 mg of morphine in group M1, or 0.2 mg of morphine in group M2 following 15 mg of isobaric spinal levobupivacaine 0.5 percent (3 mi). We recorded the following: onset and duration of sensory and motor block, duration of spinal anesthesia, time to first request for analgesia, and side effects. The onset time ofsensory block was significantly less in group M2 (3.5 + 3 minutes) than S (4 +/- 3 minutes; p < 0.003). Parturientsgiven morphine had a significantly greater duration of analgesia (554 +/- 350 minutes in group M1 and 879 -725 minutes in group M2) than the saline group (80 +/- 70 minutes; p < 0.001). Similarly, the time to first request for analgesia was longer in groups M1 (582 +/- 470 minutes) and M2 (917+/- 709 minutes) than in group S (92 +/- 77 minutes; p < 0.001). In patients undergoing cesarean delivery with CSEA, adding intrathecal morphine (0.1 and 0.2 mg) to 15 mg of spinal levobupivacaine prolonged the duration of spinal analgesia and provided rapid onset of action and longer time to first analgesic request without causing any significant side effect compared to saline.

Intrathecal fentanyl with 0.5% bupivacaine heavy in chronic opium abusers

AbstractBackground: Chronic use of opioids in opium abusers can cause poor pain control and increased analgaesic requirement. We compared the duration of spinal anaesthesia in chronic opium abusers and non-abusers.Method: This prospective randomised study included 60 American Society of Anesthesiologists (ASA) Grade I or II adults undergoing surgery under spinal anaesthesia with 10 mg bupivacaine, and 25 μg fentanyl in non-opium abusers (Group A); and chronic opium abusers (Group B), and 40 μg fentanyl in chronic opium abusers (Group C). Patients were assessed for onset and duration of sensory and motor blockade and duration of effective analgesia.Results: Mean time to onset of adequate analgesia in opium abusers was significantly longer in chronic opium abusers than in opium-naive patients. The duration of sensory block and motor block was significantly less in chronic opium abusers than in non-opium abusers. Duration of effective analgesia in groups A, B and C was 255.55 ± 26.84, 217.85 ± 15.15, and 268...

Effects of intravenous dexmedetomidine on low‐dose bupivacaine spinal anaesthesia in elderly patients

Dexmedetomidine (DMT) has been shown to prolong spinal anaesthesia. We evaluated the effects of intravenous DMT on low-dose bupivacaine spinal anaesthesia in elderly patients. Fifty-one elderly patients undergoing transurethral resection of the prostate were randomized into two groups receiving either 1.0 μg/kg DMT (DMT group, n = 26) or normal saline (control group n = 25) intravenously prior to spinal anaesthesia with 1.2 ml of bupivacaine, 5 mg/ml. The mean time to two-segment regression (39 min vs. 78 min for cold, 41 min vs. 61 min for pinprick) and that to motor regression (23 min vs. 46 min) were longer in the DMT group than in the control group. The atropine-requiring bradycardia was more frequent in the DMT group than in the control group (24.0% vs. 3.8%). The median sedation scores (ranges) during surgery were 4 (2-6) in the DMT group and 2 (1-3) in the control group (P < 0.001). Two patients in the DMT group showed oxygen desaturation (peripheral oxygen saturation < 90%) during surgery. The duration of post-operative care unit stay was longer in the DMT group than in the control group (58 min vs. 96 min). Post-operative pain intensity was lower and the mean time to first request for post-operative analgesia was longer in the DMT group compared to the control group (6.6 h vs. 2.1 h). Intravenous DMT prolonged the duration of spinal anaesthesia and improved post-operative analgesia. However, more profound sedation with desaturation was observed with more frequent bradycardia, and delayed recovery should be considered in elderly patients.

The effect of adjuvant midazolam compared with fentanyl on the duration of spinal anesthesia with 0.5% bupivacaine in opium abusers

BackgroundThere are a number of adjuvants to be used for local anesthetics in spinal block. The aim of this study was to demonstrate the possible effect of intrathecal midazolam compared with bupivacaine as adjuvants in spinal anesthesia with bupivacaine in chronic opium abuses.MethodsIn a double blind, randomized clinical trial, 90 opium abuser patients undergoing lower limb orthopedic surgery were selected and randomly assigned into 3 groups (30 cases each). The patients received 15 mg plain bupivacaine, or 15 mg bupivacaine plus 25 mcg fentanyl or 15 mg bupivacaine plus 1 mg midazolam, intrathecally.ResultsThe duration of anesthesia was much longer in the bupivacaine-midazolam group than the bupivacaine-fentanyl group; both were longer than the plain bupivacaine group (P < 0.05).ConclusionsSubarachnoid injection of adjuvant midazolam or fentanyl with plain 0.5% bupivacaine in opium abusers in lower limb orthopedic surgery increases the duration of sensory block. Therefore midazolam is more effective than fentanyl in such cases.

Effects of adjunct intrathecal magnesium sulfate to bupivacaine for spinal anesthesia: a randomized, double-blind trial in patients undergoing lower extremity surgery

The aim of this study was to evaluate the effect of additional magnesium sulfate (MgSO(4)) 100 mg to intrathecal (IT) isobaric 0.5% bupivacaine 3 ml on spinal anesthesia in patients undergoing lower extremity orthopedic surgery. In a double-blind randomized clinical trial, 79 American Association of Anesthesiologists (ASA) I or II adult patients undergoing lower extremity orthopedic surgery were recruited. The patients were randomly allocated to receive 100 mg MgSO(4) 5% (0.2 ml) plus 15 mg of bupivacaine 0.5% (MgSO(4) group) or 15 mg bupivacaine 0.5% combined with 0.2 ml normal saline (control group) intrathecally. Response to treatment was assessed as onset and duration of sensory block, the highest level of sensory block, time to complete motor block recovery, duration of spinal anesthesia, and postoperative analgesic requirement. The onset of the sensory block was slower in the MgSO(4) group than in the control group (13.3 vs. 11.6 min, P = 0.04), and the duration of the sensory blockade was significantly longer in the MgSO(4) group than the control group (106.5 vs. 85.5 min, P = 0.001). Total analgesic requirements for 24 h following surgery were lower in the MgSO(4) group than in the control group (96.8 vs. 138.5 mg, P = 0.001). Mean duration of spinal anesthesia was not significantly different between two groups (178.0 vs. 167.4 min, P = 0.23). In patients undergoing lower extremity surgery with spinal anesthesia, the addition of 100 mg IT MgSO(4) to 15 mg bupivacaine without opioid supplement, prolonged the duration of the sensory block, decreased postoperative analgesic consumption, and significantly prolonged the onset of spinal anesthesia.

The Addition of Lidocaine to Bupivacaine Does Not Shorten the Duration of Spinal Anesthesia

The duration of spinal anesthesia with bupivacaine is often too long for day surgery. A recent study of patients presenting for transurethral surgery suggested that the addition of a small amount of lidocaine to intrathecal hyperbaric bupivacaine could shorten the duration of the sensory and motor blocks. In this prospective, randomized double-blind study we investigated these findings in patients undergoing unilateral knee arthroscopy. Fifty patients were randomized to receive 2 mL hyperbaric 0.5% bupivacaine plus either 0.6 mL 1% lidocaine (lidocaine group) or 0.6 mL saline (control group). The sensory and motor blocks were monitored until complete regression and the patient was ready for discharge. The patients were interviewed 2 and 7 days after the operation about any side effects and any signs of transient neurologic syndrome. Data on 45 patients were available for analysis (24 in the lidocaine group). There was no statistically significant difference between the groups regarding time to readiness for surgery, maximum level of sensory block, total duration of sensory, and motor blocks or time to discharge from the postoperative care unit. Two patients in the control group and 1 patient in the study group had symptoms of transient neurologic syndrome for <24 hours after the operation. One patient had voiding difficulties for 3 days. All symptoms resolved spontaneously. No patient had spinal headache or backache. We did not confirm, in patients undergoing knee arthroscopy, that the addition of a small dose of lidocaine to intrathecal hyperbaric bupivacaine could shorten the duration of sensory or motor blocks or time to readiness for discharge from the postanesthesia care unit.

Volume kinetics of acetated Ringer's solution during experimental spinal anaesthesia

General anaesthesia lowers the clearance of crystalloid fluid, but the volume kinetics of such fluid throughout the duration of spinal anaesthesia has not been studied. Ten female volunteers (mean age 29 years) received an intravenous infusion of 25 ml/kg of acetated Ringer's solution with and without spinal anaesthesia. A volume kinetic model was fitted to serial measurements of the haemoglobin concentration over 240 min based on arterial, cubital vein, and femoral vein blood. The measured urine flow was compared to the model-predicted elimination. The arterial pressure remained stable, although the block reached to Th3-Th5 in half of the volunteers. There were no differences in fluid kinetics between the spinal anaesthesia and the control experiments. The administered volume was well confined to the kinetic system, which consisted of two communicating fluid spaces that were 2.8 l and approximately 7 l in size at baseline. The arteriovenous difference in plasma dilution remained positive for 30 min post-infusion in those having analgesia reaching to Th3-Th5, which differed significantly from low-level analgesia (Th12-L2, P < 0.03) when venous plasma was sampled from the leg. The urinary excretion averaged 1.13 l and 1.01 l for the spinal and control experiments, respectively. Volume kinetics predicted the urinary excretion at 5- to 10-min intervals with an overall bias of 52 ml. Acetated Ringer's solution showed the same kinetics during experimental spinal anaesthesia as when the fluid was infused alone. Hence, spinal anaesthesia is not associated with the reduced fluid clearance reported for general anaesthesia.

The dose-dependent study of verapamil and diltiazem on spinal anesthesia in the rat

The aim of this study evaluated the spinal anesthetic effect of verapamil and diltiazem. After rats were injected intrathecally with verapamil and diltiazem, dose–response curves were constructed. We evaluated the potency and duration of verapamil or diltiazem which compared with mepivacaine, a commonly used local anesthetic, in rats. Verapamil, diltiazem and mepivacaine produced a dose-dependent local anesthetic effect as spinal anesthesia. On a 50% effective dose (ED 50) basis, the spinal anesthetic effect of verapamil was more potent than diltiazem or mepivacaine ( P < 0.01 for each comparison). On an equipotent basis (ED 25, ED 50, and ED 75), the blockade duration of spinal anesthesia caused by diltiazem was longer than that caused by verapamil or mepivacaine ( P < 0.01 for each comparison). In summary, verapamil produced more potent spinal blockades, when compared with diltiazem or mepivacaine. Diltiazem demonstrated longer spinal blockades than did verapamil or mepivacaine.

Intrathecal clonidine decreases propofol sedation requirements during spinal anesthesia in infants

Propofol is a popular agent for providing procedural sedation in pediatric population during lumbar puncture and spinal anesthesia. Adjuvants like clonidine and fentanyl are administered intrathecally to prolong the duration of spinal anesthesia and to provide postoperative analgesia. We studied the propofol requirement after intrathecal administration of clonidine or fentanyl in infants undergoing lower abdominal surgeries. Sixty-five ASA I infants undergoing elective lower abdominal surgery under spinal anesthesia were assigned into four groups in this prospective randomized double-blinded study. Group B received bupivacaine based on body weight (<5 kg = 0.5 mg kg(-1); 5-10 kg = 0.4 mg kg(-1)). Group BC received 1 microg kg(-1) of clonidine with bupivacaine, group BF received 1 microg kg(-1) of fentanyl with bupivacaine, and patients in group BCF received 1 microg kg(-1) each of clonidine and fentanyl with bupivacaine. A bolus of 2-3 mg kg(-1) of propofol bolus was administered for lumbar puncture. Sedation was assessed using a six-point sedation score (0-5) and a five-point reactivity score (0-4) which was based on a behavioral score. After achieving a sedation and reactivity score of 3-4, the patients were placed lateral in knee chest position and lumbar puncture performed and test drug administered. Further intraoperative sedation was maintained with an infusion of 25-50 microg kg(-1) min(-1) of propofol infusion. The mean +/- SD infusion requirement of propofol decreased from 35.5 +/- 4.5 in group B to 33.4 +/- 5.4 microg kg(-1) min(-1) in group BF and further decreased to 16.7 +/- 6.2 microg kg(-1) min(-1) and 14.8 +/- 4.9 microg kg(-1) min(-1) in group BC and BCF, respectively. There were no statistically significant differences between BC and BCF groups. The mean sedation and reactivity scores were higher in groups BC and BCF when compared to groups B and BF. Our study show that the requirement of propofol sedation reduces with intrathecal adjuvants. The reduction was significant with the addition of clonidine and clonidine-fentanyl combination as opposed to bupivacaine alone or with fentanyl. There was no significant difference in propofol infusion requirement with the use of bupivacaine alone or with fentanyl.

The effects of intravenous dexmedetomidine on spinal hyperbaric ropivacaine anesthesia

In this study we investigated the effects of intravenously administered dexmedetomidine on the duration of hyperbaric ropivacaine in spinal anesthesia, and the side effects. In a prospective, double-blind study, sixty ASA I-II patients were randomized to two groups of 30 individuals. All patients were administered hyperbaric ropivacaine (22.5 mg) for spinal anesthesia. Intravenous dexmedetomidine was administered in group I for 60 min, physiological saline at the same amount and duration was infused in group II. Measurements of mean blood pressure before and after the procedure revealed significant decreases in group I compared with group II after 20, 25, and 30 min. The times for two dermatomes regression of the blockade and complete resolution of motor blockade were significantly prolonged in group I. The sedation score in the dexmedetomidine group was significantly increased compared with controls. Atropine requirement was found to be significantly higher in group I than in group II. Our results show that intravenously administered dexmedetomidine prolonged the duration of spinal anesthesia, provided sufficient sedation, and had few side effects. Therefore, dexmedetomidine is appropriate during spinal anesthesia, if the anesthesiologist is alert for development of bradycardia.

Effects of intrathecal fentanyl on quality of spinal anesthesia in children undergoing inguinal hernia repair

The effect of intrathecal fentanyl on the characteristics of spinal anesthesia has not been investigated in children undergoing inguinal hernia repair. The purpose of this study was to assess whether the incidence and severity of pain during peritoneal sac traction is decreased by addition of fentanyl to bupivacaine in children undergoing inguinal hernia repair with spinal anesthesia. Children (6-14 years) were randomized into two groups. Group F (n = 25): hyperbaric bupivacaine plus 0.2 microg.kg(-1) of fentanyl. Group P (n = 25): hyperbaric bupivacaine plus 0.9% NaCl (placebo). The dose of bupivacaine was 0.4 mg.kg(-1). The primary variable was the incidence and severity of pain during peritoneal sac traction. Spinal block characteristics, duration of spinal anesthesia assessed by recovery of hip flexion and duration of analgesia were the secondary variables measured, and the side effects were noted. There were significant differences in incidence of pain and pain scores during sac traction with lower incidence and scores in the fentanyl group (P = 0.009). Two groups were similar regarding the level of sensory block during sac traction and duration of spinal anesthesia. Duration of spinal analgesia was prolonged significantly in the fentanyl group (P = 0.025). Intrathecal fentanyl at a dose of 0.2 microg.kg(-1) added to bupivacaine significantly improves the quality of intraoperative analgesia and prolongs postoperative analgesia in children undergoing inguinal hernia repair with spinal anesthesia.

A randomised study of magnesium sulphate as an adjuvant to intrathecal bupivacaine in patients with mild preeclampsia undergoing caesarean section

Background Adequate analgesia following caesarean section decreases morbidity, hastens ambulation, improves patient outcome and facilitates care of the newborn. Intrathecal magnesium, an NMDA antagonist, has been shown to prolong analgesia without significant side effects in healthy parturients. We therefore studied the effect of adding intrathecal magnesium sulphate to bupivacaine-fentanyl spinal anaesthesia in patients with mild preeclampsia undergoing caesarean section. Methods Sixty women with mild preeclampsia undergoing caesarean section were included in a prospective, double blind, placebo-controlled trial. Patients were randomly assigned to receive spinal anaesthesia with 2 mL 0.5% hyperbaric bupivacaine and 25 μg fentanyl with either 0.1 mL of 0.9% sodium chloride (control group) or 0.1 mL of 50% magnesium sulphate (50 mg) (magnesium group). Onset, duration and recovery of sensory and motor block, time to maximum sensory block, duration of spinal anaesthesia and postoperative analgesia requirements were studied. Results The onset of both sensory and motor block was slower in the magnesium group. The duration of spinal anaesthesia (229.3 vs. 187.7 min) and motor block (200 vs. 175.3 min) were significantly longer in the magnesium group. Diclofenac requirement for 24 h following surgery was significantly lower in the magnesium group (147.5 vs.182.5 mg, P=0.02). Haemodynamic parameters and side effect profile were similar in the two groups. Conclusions In parturients with mild preeclampsia undergoing caesarean delivery, the addition of magnesium sulphate 50 mg to the intrathecal combination of bupivacaine and fentanyl prolongs the duration of analgesia and reduces postoperative analgesic requirements without additional side effects.

Dexmedetomidine prolongs spinal anaesthesia induced by levobupivacaine 0.5% in guinea-pigs

Alpha-2 adrenoceptor agonists have been used in association with local anaesthetic to increase the duration of spinal anaesthesia. Intrathecal administration of clonidine prolonged motor blockade induced by local anaesthetic. Since the affinity of dexmedetomidine (DEX) to alpha-2 adrenoceptors is eight-times greater than clonidine, it is expected that DEX could be advantageous in clinical anaesthesia. We investigated the duration of motor nerve block induced by spinal injection of 0.5% levobupivacaine (LVB) associated with intrathecal or intraperitoneal administration of DEX. Seventy-two guinea-pigs were randomly divided in 12 groups, which were all treated with intrathecal injection of 50 microL of LVB. DEX was injected intrathecally with LVB in 6 groups or injected intraperitoneally after LVB in another 6 groups. Intrathecal DEX (0.1, 0.2 and 0.4 microg) increased the LVB-induced motor anaesthesia from 48 (41-66) min to 84.5 (52-91) min (P < 0.05), 101.5 (83-115) min (P < 0.05) and 105 (97-114) min (P < 0.05), respectively. Similarly, intraperitoneal DEX (20 and 40 microg kg(-1)) increased the motor blockade from 48.5 (33-59) min to 88 (71-114) min (P < 0.05) and 114.5 (103-156) min (P < 0.05), respectively. Pre-treatment with yohimbine reduced the duration of motor block from 101.5 (83-115) to 76.5 (68-86) min (P < 0.05) or from 114.5 (103-156) to 90 (83-93) min (P < 0.05) when DEX was administered by the intrathecal or intraperitoneal routes. Motor block induced by spinal injection of LVB was prolonged by intrathecal and systemic administration of DEX, which was partially dependent on activation of alpha-2 adrenoceptors.

Cephalad migration of intrathecal clonidine in an infant undergoing bilateral herniorrhaphy

To the Editor, Intrathecal clonidine is often added to bupivacaine to prolong the duration of spinal anesthesia in the pediatric population. However, there may be important central nervous system (CNS) effects due to cephalad spread of clonidine following intrathecal administration of a clonidine–bupivacaine mixture. A 3 -month-old full-term male infant (51 weeks postconception) weighing 5 kg was scheduled for bilateral inguinal hernia repair. Preoperative evaluation was unremarkable, except for the presence of an asymptomatic atrial septal defect measuring 4.5 mm in diameter. After obtaining written parental consent, the infant was sedated with propofol (10 mg bolus and infusion at 25 lg kg min). A lumbar puncture was performed using a 25 mm, 25 G spinal needle (Beckton Dickinson, Madrid, Spain) with the patient in the left lateral position. Intrathecal clonidine 5 lg and hyperbaric bupivacaine 2.5 mg (0.5%) were administered in a volume of 0.53 mL. The infant was then turned supine. The height of spinal block was T3 after five minutes. Within eight minutes, the infant was deeply sedated and propofol sedation was discontinued. However, the infant continued to be deeply sedated and lethargic, and there was flaccidity with no spontaneous movement of either upper limb. No clinically significant hypotension, bradycardia, or desaturation were observed, but the patient’s respiratory efforts were inadequate with intermittent apneic episodes. Therefore, tracheal intubation was performed after administration of thiopental 10 mg iv, and anesthesia was maintained with sevoflurane and nitrous oxide. The duration of surgery was 62 min. The inhalational agents were then discontinued, and the patient was transferred to the postanesthesia care unit where mechanical ventilation was maintained. Return of movement in the infant’s upper limbs was first noted 7 hr and 26 min after administration of spinal anesthesia, with complete recovery of motor function in all limbs 8 hr after block administration. The trachea was then extubated. The first need for rescue analgesia was at 8 hr and 17 min. The patient was observed for 72 hr in the step-down unit where no apneic episodes, desaturation, or hemodynamic instability were noted. Intrathecal doses of bupivacaine 0.5 mg kg and clonidine 1 lg kg, normally provide spinal blockade without adverse effects. The total volume given was 0.53 mL or approximately 0.1 mL kg. In infants, volumes of up to 0.2 mL kg have been used without significant adverse effects. The flaccidity of limb muscles, prolonged sedation, and respiratory depression suggests the occurrence of CNS toxicity with clonidine. Such toxicity has been observed with various routes of administration of clonidine, including eye drops. Common clinical features of clonidine toxicity are variable and include somnolencelethargy (96%), miosis (56%), and respiratory depression (48%), with treatment being mainly supportive. Children seem to be unusually sensitive to the depressant effects of clonidine. In this case, the intrathecally administered clonidine–bupivacaine mixture might have caused CNS toxicity due to cephalad spread of clonidine. As a result, CNS manifestations, such as somnolence, hypotonia, and respiratory depression, were produced without effects on other organ systems. On its own, a high level of spinal anesthesia produces sedation, but the block is expected to S. V. Rakesh, MBBS S. Rajeev, MD Y. K. Batra, MD (&) K. L. N. Rao, MCh Postgraduate Institute of Medical Education and Research, Chandigarh, India e-mail: ykbatra@glide.net.in

Intrathecal neostigmine with bupivacaine for infants undergoing lower abdominal and urogenital procedures: dose response

Intrathecal (IT) neostigmine produces dose-dependent analgesia in adults. However, the dose of spinal neostigmine has not been investigated in infants. The purpose of this study was to assess spinal anesthesia (SA) duration provided by four doses of spinal neostigmine added to bupivacaine for lower abdominal and urogenital procedures in infants. Seventy-five infants were randomized into five groups. The control group B received IT plain 0.5% hyperbaric bupivacaine. Groups BN.25, BN.50, BN.75, and BN1.0 received bupivacaine with 0.25, 0.5, 0.75, and 1 microg/kg of neostigmine, respectively. The primary variable was the duration of anesthesia assessed by recovery of hip flexion. Postoperative pain with facial expression, leg activity, arm activity, crying and consolability scale score, and rescue analgesic requirements were the secondary variables measured, and the side effects were noted. Seventy-three infants completed the study. There was a significant linear increase in SA duration with IT neostigmine to 65.2 (4.3) min with 0.5 microg/kg (P<0.01), 88.2 (5.1) with 0.75 microg/kg (P<0.001) and 92 (4.3) with 1 microg/kg (P<0.001) from 52.4 (4.3) min with bupivacaine alone. SA duration showed no significant difference between plain bupivacaine and BN.25 (P=0.100) or between groups BN.75 and BN1.0 (P=0.451). Groups BN.75 and BN1.0 had significantly reduced pain scores, and the median duration before the first dose rescue analgesic was requested prolonged significantly (P<0.001) compared with the other three groups. IT neostigmine at a dose of 0.75 microg/kg added to bupivacaine significantly prolonged SA duration with reduced postoperative pain scores and rescue analgesic requirements in infants undergoing lower abdominal and urogenital procedures. No additional benefits were provided on increasing it to 1 microg/kg.

Comparison of intrathecal magnesium, fentanyl, or placebo combined with bupivacaine 0.5% for parturients undergoing elective cesarean delivery

Intrathecal (i.t.) administration of magnesium has been reported to potentiate opioid antinociception in rats and humans. In this prospective, randomized, double-blind, study, we investigated the sensory, motor, and analgesic block characteristics of i.t. magnesium 50 mg compared with fentanyl 25 microg and saline when added to 0.5% bupivacaine (10 mg). Ninety ASA I or II adult patients undergoing cesarean section were randomly allocated to receive 1.0 ml of 0.9% sodium chloride in group S, 50 mg of magnesium sulfate (1.0 ml) 5% in group M, or 25 microg of fentanyl (1.0 ml) in group F following 10 mg of bupivacaine 0.5% i.t. We recorded the following: onset and duration of sensory and motor block, maximal sensory block height, the time to reach the maximal dermatomal level of sensory block, and the duration of spinal anesthesia. Magnesium did not shorten the onset time of sensory and motor blockade or prolong the duration of spinal anesthesia. The duration of sensory (P<0.032) and motor (P<0.002) blockade was significantly shorter in M and S groups than in the F group. The time to reach the maximal dermatomal level of sensory block was significantly shorter in the F group than in the S and M groups (P<0.002). In patients undergoing cesarean section with spinal anesthesia, the addition of magnesium sulfate (50 mg) i.t. to 10 mg of spinal bupivacaine (0.5%) did not shorten the onset time of sensory and motor blockade or prolong the duration of spinal anesthesia, as seen with fentanyl.

Comparison of hyperbaric and plain articaine in spinal anaesthesia for open inguinal hernia repair

BackgroundFast onset and short duration are prominent properties of the amide-type local anaesthetic articaine. Similar to bupivacaine, a hyperbaric solution of articaine may produce faster onset and shorter duration of spinal anaesthesia than a plain solution. MethodsPatients undergoing open inguinal hernia repair received in random order articaine 84 mg in either hyperbaric (HyperA, n=49) or plain solution (PlainA, n=48) intrathecally. A blinded observer tested the dermatomal spread (pinprick) and motor block (Bromage scale). ResultsMedian (range) onset time to the T10 dermatome was 2 (2–8) (n=46) and 6 (2–30) min (n=39) (P<0.001), and the duration of the sensory block at (or above) the T10 dermatome was 86 (39–148) and 69 (15–118) min (P=0.007), in Groups HyperA and PlainA, respectively. Peak sensory block was greater in Group HyperA T4 (L2–C2) than in Group PlainA T8–T7 (L3–T3) dermatome, median (range), P<0.001. Spread of the block to the cervical dermatomes associated with hypotension occurred in three patients of Group HyperA (one patient C2 and two C4). The sensory block resolved to the S2 dermatome significantly faster in Group HyperA, 2.5 (1.5–4.5) h, than in Group PlainA, 3.5 (2.0–4.5) h (P<0.001). Median duration of the motor block was significantly shorter in Group HyperA, 2.0 (1.3–3.5) vs 3.0 (1.5–4.0) h (P<0.001). ConclusionsHyperbaric articaine 84 mg had a faster onset and shorter duration of spinal anaesthesia than the plain solution.