Intrathecal ropivacaine for ambulatory surgery.

BACKGROUND: The rationale of this study was to evaluate intrathecal ropivacaine for ambulatory surgery. METHODS: One hundred fifty patients with American Society of Anesthesiologists physical status 1 scheduled for knee arthroscopy were studied. Patients were randomly assigned to receive 4 ml of one of five isobaric intrathecal solutions: Patients in group 1 (n = 30) received 8 mg of bupivacaine; patients in group 2 (n = 30) received 8 mg ropivacaine; patients in group 3 (n = 30) received 10 mg ropivacaine; patients in group 4 (n = 30) received 12 mg ropivacaine; and patients in group 5 (n = 30) received 14 mg ropivacaine. The level and duration of sensory anesthesia were recorded along with the intensity and duration of motor block. Patients were interviewed to identify transient neurologic symptoms. RESULTS: Intrathecal ropivacaine 10 mg produced shorter sensory anesthesia and motor blockade than bupivacaine 8mg (152 +/- 44 min and 135 +/- 41 min vs. 181 +/- 44 min and 169 +/- 52 min, mean +/- SD; P < 0.05). However, the quality of intraoperative analgesia was significantly lower in the 10-mg ropivacaine group (P < 0.05). Ropivacaine 12 mg produced sensory and motor block almost comparable to bupivacaine 8 mg. Ropivacaine 14 mg produced sensory and motor block comparable to ropivacaine 12 mg but significantly increased the time to void. No sign of transient radicular irritation were noted. CONCLUSION: Intrathecal ropivacaine 12 mg is approximately equivalent to bupivacaine 8 mg. At this dose, ropivacaine offers no significant advantage compared with bupivacaine.

A double-blind comparison of 0.125% ropivacaine with sufentanil and 0.125% bupivacaine with sufentanil for epidural labor analgesia.

BACKGROUND: This study intends to evaluate the benefits of the administration of intermittent bolus doses of ropivacaine (0.125%) compared with bupivacaine (0.125%) after addition of sufentanil for analgesia during labor. METHODS: One hundred thirty American Society of Anesthesiologists physical status 1 or 2 parturients were studied. The 90 initial patients were assigned randomly to receive 10 ml bupivacaine, 0.125%, plus 7.5 microg sufentanil (initial bupivacaine 0.125% group) or ropivacaine, 0.125%, plus 7.5 microg sufentanil (ropivacaine 0.125% group). Forty additional patients were recruited and received 0.125% bupivacaine plus 7.5 microg sufentanil (additional bupivacaine 0.125% group) or 0.100% bupivacaine plus 7.5 microg sufentanil (additional bupivacaine 0.100% group). The duration of analgesia, visual analogue scores for pain, motor blockade (using a six-point modified Bromage scale), patient satisfaction scores, nausea, pruritus, heart rate, and blood pressure were recorded. RESULTS: Bupivacaine 0.125% and ropivacaine 0.125% coadministered with sufentanil provided rapid and complete analgesia. Onset of analgesia occurred after +/-15 min and lasted +/-90 min. After the third epidural injection, patients in the ropivacaine group experienced significantly less severe motor blockade than patients in the initial bupivacaine 0.125% group. At this point, 93% of the patients in the ropivacaine group were free from motor impairment versus 66% in the bupivacaine group (P<0.05). Comparable levels of motor blockade were obtained in both additional groups. Patients' evaluation of their analgesia was worst in the bupivacaine 0.100% group. CONCLUSIONS: Ropivacaine 0.125% with sufentanil affords reliable analgesia with minimal motor blockade.

Intrathecal clonidine combined with sufentanil for labor analgesia.

BACKGROUND: Intrathecal sufentanil provides rapid-onset and complete analgesia for the first stage of labor. The dose required to produce this effect can be associated with maternal respiratory depression, hypotension, nausea, or pruritus. Because clonidine potentiates the analgesic effects of opioids without increasing their side effects, the authors wanted to determine the efficacy of low doses of intrathecal clonidine (15 and 30 microg) combined with sufentanil. METHODS: Ninety-eight parturient requesting labor analgesia were studied. In a combined spinal-epidural technique, patients were randomly assigned to receive one of the following intrathecal solutions: either 15 microg clonidine (n = 10); 30 microg clonidine (n = 10); 2.5 microg sufentanil (n = 13); 5 microg sufentanil (n = 13); 2.5 microg sufentanil and 15 microg clonidine (n = 13); 2.5 microg sufentanil and 30 microg clonidine (n = 13); 5 microg sufentanil and 15 microg clonidine (n = 13); or 5 microg sufentanil and 30 microg clonidine (n = 13). Visual analog scores for pain, blood pressure, heart rate, sensory levels, incidence of nausea and pruritus, and motor blockade, and maternal and cord blood concentrations of clonidine were recorded. RESULTS: Patients receiving 30 microg intrathecal clonidine with 2.5 or 5 microg intrathecal sufentanil had significantly longer-lasting analgesia (145 +/- 36 and 145 +/- 43 min vs. 104 +/- 35 for those receiving 5 microg intrathecal sufentanil alone). Clonidine levels were undetectable in maternal serum. CONCLUSIONS: Thirty micrograms of intrathecal clonidine combined with 2.5 or 5 microg intrathecal sufentanil significantly increased the duration of analgesia during the first stage of labor without adverse maternal or fetal effects.

Ambulatory combined spinal-epidural analgesia for labor. Influence of epinephrine on bupivacaine-sufentanil combination.

BACKGROUND AND OBJECTIVES: Subarachnoid sufentanil 5 micrograms during labor is known to have variable results. However, subarachnoid sufentanil 5 micrograms plus bupivacaine 1 mg provides good quality labor analgesia of 100 minutes' average duration. The objective of this study was to examine the effects of adding epinephrine 25 micrograms to this mixture. METHODS: Forty-two parturients with less than 5 cm cervical dilation participated in this double-blind, randomized study. A combined spinal-epidural technique was used for subarachnoid administration of sufentanil 5 micrograms and bupivacaine 1 mg with or without epinephrine 25 micrograms. Analgesia was assessed by visual analog scores. Time elapsed until first request for additional analgesia, blood pressure, heart rate, sensory levels, motor block, and incidence of pruritus, nausea, and sedation were noted. RESULTS: Addition of epinephrine prolonged the duration of analgesia from 103.8 +/- 28.2 minutes to 142 +/- 54.3 minutes and lowered the median cephalad level of sensory block from T3 to T6. The incidence of side effects was similar in both groups, as was the motor performance; 19 patients were able to ambulate in each group. CONCLUSIONS: This minimal bupivacaine-sufentanil-epinephrine mixture allows high-quality analgesia of 142 +/- 54.3 minutes' duration, with a low sensory block level and no motor block. However, hypotension can occur as a late side effect.

Intravenous regional anesthesia. Evaluation of 4 different additives to prilocaine.

Intravenous regional anesthesia (IVRA) is an effective method of producing anesthesia of the extremities. Disadvantages are the rapid loss of anesthesia after the deflation of the tourniquet and the rapid development of postoperative pain. This study compared the effect of four different additives to prilocaine with saline on the development of a complete sensory block, on the return of sensory function after deflation of the tourniquet and on the development of postoperative pain after IVRA for minor orthopedic surgery of the arm. Seventy-five patients, ASA class 1 or 2, were randomly divided into 5 groups. All patients received 30 ml. of prilocaine 1%, together with 5 ml. of additive. In group 1, the additive was saline, in group 2 bupivacaine 0.25%, in group 3 clonidine 150 micrograms in saline, in group 4 sufentanil 25 micrograms in saline and in group 5 tenoxicam 20 mg. The development of a complete sensory block proved significantly faster in the patients receiving sufentanil (4.8 min.) as compared to plain prilocaine (7.5 min.). The return of the sensory function was comparable for all groups. Postoperative pain scores were significantly better in the clonidine and tenoxicam groups.

Spinal analgesia during labor with low-dose bupivacaine, sufentanil, and epinephrine. A comparison with epidural analgesia.

BACKGROUND AND OBJECTIVES: The purpose of this investigation was to evaluate the effectiveness and side effects of combined spinal-epidural (CSE) injection of a bupiv-acaine-sufentanil-epinephrine mixture during labor as compared with epidural analgesia alone. METHODS: In a randomized trial, 63 parturients presenting for vaginal delivery received either epidural analgesia (10 mL) with 12.5 mg bupivacaine plus 10 micrograms sufentanil and 12.5 micrograms epinephrine or CSE analgesia with a single subarachnoid injection of 1 mg bupivacaine plus 5 micrograms sufentanil and 25 micrograms epinephrine (total volume, 2.5 mL). For this purpose a 29-gauge BD-Quincke spinal needle was used. All subsequent top-ups consisted of 10 mL of the mixture, as used for the patients who received epidural analgesia only. RESULTS: Thirteen patients delivered without requesting a second injection. The time required to obtain satisfactory analgesia (visual analog score < or = 2.5 and/or > 50% improvement) was significantly shorter for those who received the subarachnoid mixture than for the epidural analgesia group (4.0 +/- 0.4 vs 10.4 +/- 0.5 minutes, respectively, P < .001). The duration of analgesia was longer for the CSE group (137.4 +/- 11.5 vs 106.4 +/- 11.8 minutes, P < .05), with more patients being pain-free for longer than 150 minutes (40 vs 8%, P < .05). Less bupivacaine was consumed in the group receiving the subarachnoid mixture (21.6 +/- 2.0 vs 30.7 +/- 2.1 mg, P < .01). Pruritus was more common following subarachnoid than following epidural injection of sufentanil (53.1 vs 25.8%, P < .05). Other side effects related to the injected drugs, such as motor impairment, hypotension, or nausea or vomiting, were not observed. Although all blocks were uneventful, moderate headache compatible with postdural puncture headache occurred in two patients of the CSE group, which necessitated a blood patch after 5 days. CONCLUSIONS: The CSE mixture induced long-lasting analgesia, with fast onset and without motor block or hypotension. Pruritus and headache were the major drawbacks of this technique.

Hydroxyethylstarch compared with modified gelatin as volume preload before spinal anaesthesia for Caesarean section.

We studied 90 patients undergoing elective Caesarean section under spinal anaesthesia who received lactated Ringer's solution 1000 ml with up to 1000 ml of modified gelatin, lactated Ringer's solution 1000 ml with up to 1000 ml of 6% hydroxyethylstarch or only up to 1000 ml of 6% hydroxyethylstarch. Lumbar puncture was performed as soon as 500 ml of the colloid were infused. The incidence of hypotension, number of patients requiring a vasopressor and doses of ephedrine required to restore arterial pressure were significantly lower in favour of those receiving the crystalloid-hydroxyethylstarch combination. In both groups receiving the 2000 ml preload, packed cell volume (PCV) values decreased by more than 20%, which may be of concern in patients already presenting with mild anaemia. In patients who received the colloid without the crystalloid, PCV values decreased by 14% but the risk of severe hypotension was comparable with the crystalloid-gelatin combination.

Sequential spinal epidural analgesia for pain relief in labour: an audit of 620 parturients.

This investigation was designed to evaluate sequential spinal epidural analgesia with a needle through needle technique for pain relief in labour. The spinal injection was made using a Becton Dickinson 29 gauge Quincke point needle. Bupivacaine 1 mg, sufentanil 5 microg and adrenaline 25 microg (2 ml) were injected intrathecally. Analgesia was maintained using bupivacaine 12.5 mg, sufentanil 10 microg and adrenaline 12.5 microg in a 10 ml bolus given through an epidural catheter in the epidural space. This dosage was also used for the test dose. Pain relief was obtained in less than ten minutes and lasted for a mean of 134 min. Of the 620 parturients in the investigation, 500 had a mean dose of 4.3 mg bupivacaine per hour. Hypotension and paresis were of no concern. Patient satisfaction was excellent, 85% of the parturients being very satisfied and 10% satisfied.

Epidural sufentanil for postoperative patient-controlled analgesia (PCA) with or without background infusion: a double-blind comparison.

To evaluate the usefulness of a concurrent infusion in patient-controlled epidural analgesia (PCEA), 40 patients scheduled for elective cesarean section under a combined spinal-epidural technique were assigned randomly in a double-blind fashion to receive sufentanil by PCEA with a concomitant infusion of either sufentanil or saline. The sufentanil 24-h consumption was significantly (P < 0.001) higher in those patients receiving the opioid-containing infusion (212.7 +/- 9.5 vs 128.4 +/- 10.8 micrograms, SEM). The number of additional demands and the quality of sleep did not differ between the two groups. The degree of sedation was significantly less pronounced in patients treated with incremental sufentanil doses only. The visual analog scale (VAS) pain scores at rest were identical in both groups except at 6 h (2.5 +/- 0.4 vs 3.7 +/- 0.3, in favor of the patients treated with the sufentanil background infusion). We conclude that, except for a lower pain score during the initial hours, a background infusion in PCEA with sufentanil does not offer major advantages in terms of sleep quality or sufentanil consumption. Side effects may be more pronounced owing to increased drug administration.

Does epidural injection of physiological saline facilitate the advancement of catheters?

Seventy patients (ASA I, ASA II), scheduled for a surgical intervention under epidural or combined spinal-epidural anaesthesia, were randomly allocated to one of two groups. The epidural space was identified by loss of resistance using air, followed by injection in Group A (35 patients) of 10 ml of physiological saline directed cephallad and in Group B (35 patients) by no injection. Thereafter an anaesthetist, different to the one who placed the Tuohy in the epidural space, advanced a catheter up to 10 cm into the epidural space. At each cm of advance the resistance was judged. No significant difference in resistance was found between the groups. The authors conclude that the injection of 10 ml of physiological saline into the epidural space does not facilitate the advancement of an epidural catheter.

Atraucan: a new needle for spinal anesthesia.

BACKGROUND AND OBJECTIVES: Atraucan 26-gauge spinal needles have a tip designed to make a small linear cut (as opposed to a V-shaped cut) in the dura mater. The cut is shorter than the outside diameter of the needle and is dilated as the needle passes through the dura. The needle is used with a 20-gauge introducer. In vitro, it causes less leakage of cerebrospinal fluid than Quincke 26-gauge or Sprotte 24-gauge needles. This study was designed to test the ease of use and any damage caused to the needle tip during lumbar dural puncture. METHODS: This was a multicenter trial (six centers in five countries) involving 362 patients undergoing spinal anesthesia. A detailed questionnaire was filled in for every patient by the anesthesiologist. All the needles were returned to the factory and examined microscopically for damage. RESULTS: Lumbar dural puncture was successful in all but one patient. Spinal anesthesia was satisfactory for the planned surgery in 97%. Microscopy of the needle tips showed only a minor degree (0.01-0.19 mm) of bending in 14%, and none of the tips had a "hook." Postdural puncture headache (PDPH) occurred in nine patients (2.5%), all but one of whom (a 15-year-old male) were females under 55 years of age. CONCLUSIONS: The Atraucan needle is easy to use and has a high success rate in identifying the subarachnoid space. Lumbar dural puncture causes minimal damage to the tip. The incidence of PDPH is low, but a larger comparative study needs to be performed.

A loss-of-resistance-to-negative-pressure test for subarachnoid puncture with narrow-gauge needles.

BACKGROUND AND OBJECTIVES: Approximately 5-10% of attempted myelograms are spoiled by partial subdural injection. Similar spillage of local anesthetics may underlie the wide variability of segmental spread reported for spinal anesthesia. A technique of applied negative pressure to avoid accidental subdural injection and to facilitate subarachnoid puncture with narrow gauge needles is described. METHODS: Hydraulic circuitry was designed to measure saline flow rates through spinal needles at hub-to-tip differential pressures of 55 mm Hg and 650 mm Hg. A model of dura and arachnoid membranes was constructed to demonstrate the effects of applied negative pressure on the subdural space during the passage of Quincke-tip and pencil-point needles. Cisternal puncture in 38 dogs and thoracic or lumbar subarachnoid puncture in 680 patients were performed using applied negative pressure to the needle hub. RESULTS: A sustained vacuum of -650 mm Hg at the hub of air-filled spinal needles was transmitted beyond the tip but fell to zero at the tip as the shaft filled with saline. Flow rates through the Quincke needles, ranging from 22-gauge to 29-gauge, rose 22- to 33-fold when a vacuum of -650 mm Hg was applied at the hub. Model dura and arachnoid membranes were separated by air-filled tips at atmospheric pressure but were juxtaposed by negative pressure applied to the hub. CONCLUSIONS: Negative pressure applied to the needle hub is transmitted to the tip without decrement in air-filled needles but not in fluid-filled needles. Clinical application of this principle by exertion of strong negative pressure at the hub during needle advancement facilitates rapid identification of cerebrospinal fluid, avoids unintentional subdural injection of local anesthetics or contrast media, and increases the safety of subarachnoid punctures above the termination of the spinal cord.

The effects of the addition of sufentanil to 0.125% bupivacaine on the quality of analgesia during labor and on the incidence of instrumental deliveries.

In a double-blinded, randomized, prospective multi-center study of 695 women, we investigated whether epidural injection of sufentanil added to 0.125% bupivacaine with epinephrine (1:800,000) reduces the total amount of local anesthetic required, resulting in less motor blockade and reduced incidence of instrumental deliveries, and improves the quality of analgesia provided by this low concentration of local anesthetic without jeopardizing the safety of the baby. In addition, other potential benefits of sufentanil (such as decrease in the incidence of shivering) and side effects were examined. It was found that adding incremental doses of 10 micrograms sufentanil up to a maximum of 30 micrograms reduced the incidence of instrumental deliveries from 36 to 24% (P less than 0.01) and significantly improved quality and duration of analgesia without depressing the neurobehavioral status of the baby. No other benefits from adding sufentanil were found. The only side effect that occurred more frequently after sufentanil was pruritus. We conclude that epidural injection of 10-30 micrograms sufentanil added to 0.125% bupivacaine with epinephrine (1:800,000) improved the quality of analgesia during labor and reduced the incidence of instrumental deliveries without jeopardizing the safety of the baby.

Guillain-Barre syndrome after obstetrical epidural analgesia.

Guillain Barre Syndrome (GBS) occurred 24 hours post-partum following an obstetrical epidural anesthetic (OEA) procedure. Clinical diagnosis was confirmed by cerebrospinal fluid (CSF) findings and nerve conduction velocity studies. GBS is an immune mediated process. Because of short latency between the onset of symptoms and the performance of the epidural block, a cause and effect relationship between epidural block and GBS in this patient is unlikely.

Comparison between propofol and midazolam as sedative agents for surgery under regional anaesthesia.

Propofol (25 patients) or midazolam (25 patients) was used to provide sedation in patients who underwent abdominal or orthopaedic surgery under epidural anaesthesia after intravenous premedication with droperidol 1 mg and fentanyl 20 micrograms. The quality of sedation whilst the block was performed, was assessed as good in 19 patients after propofol 1.49 mg/kg but six patients exhibited uncontrolled movement. Good sedation was provided in 22 patients after midazolam 3 mg. A mean infusion rate of propofol of 1.74 mg/kg/hour resulted in easily controllable sedation during the procedure. Eleven patients given midazolam required no further sedation but a mean of 5.79 mg was needed in the remaining 14 patients; the dose was unpredictable in individual patients. Recovery was significantly more rapid in the propofol group.

Extradural bupivacaine with sufentanil for vaginal delivery. A double-blind trial.

The combination of sufentanil with bupivacaine plus adrenaline given extradurally for pain relief during labour was studied in a double-blind trial. One hundred and twenty patients were randomly divided into three groups and received a 10-ml extradural injection of sufentanil 15 micrograms + bupivacaine 12.5 mg + adrenaline 12.5 micrograms, sufentanil 7.5 micrograms + bupivacaine 12.5 mg + adrenaline 12.5 micrograms, or bupivacaine 12.5 mg + adrenaline 12.5 micrograms (control group). A second injection, which was given upon request, was identical to the first. Subsequently, patients received a further 10 ml of bupivacaine + adrenaline, if required. The addition of sufentanil significantly decreased the latency, and increased the duration, of the analgesia. Moreover, the quality of analgesia was better and less bupivacaine was required, resulting in less motor blockade at delivery. There were no differences between the three groups in regard to Apgar scores. The only side effect of sufentanil was pruritus.

Sedatives in regional anesthesia.

In regional anesthesia our experience shows that the association of small dose of fentanyl (20 mcg i.v.) and droperidol (1 mg i.v.) with a small dose of benzodiazepine i.v. injected 5' after provides a good sedation during surgery. The choice of the benzodiazepine is based on the duration of anesthesia: midazolam (1.5 or 3 mg i.v.) in anesthesia with a duration less or equal to 1 h 30'; flunitrazepam (0.2 mg or 0.4 mg i.v.) in anesthesia with a duration longer than 1 h 30'.

Protein binding of the analgesics alfentanil and sufentanil in maternal and neonatal plasma.

Maternal and umbilical venous plasma was obtained at delivery from 8 mothers and their neonates after an i.v. bolus injection of alfentanil, and from 6 mothers and their neonates after epidural administration of sufentanil. Plasma levels of total (free + bound) alfentanil in neonates were about 3.4-times lower than in their mothers. At 33-55 min after 30 micrograms sufentanil, total drug levels in mothers were around the limit of detection of the radioimmunoassay (0.05 ng/ml); in one mother who had received 250 micrograms, the plasma level of total sufentanil was 2.6-times higher than in her neonate. Plasma protein binding of alfentanil was 88.2% in mothers and 67.2% in neonates. Plasma protein binding of sufentanil was 90.7% in mothers and 79.3% in neonates. For both drugs, plasma protein binding was significantly related to the alpha 1-acid glycoprotein (alpha 1-AGP) level, which was about 2.5-times lower in the infants. Free alfentanil levels in mothers and neonates were similar. Free levels of sufentanil in mothers and neonates differed less from each other than did the total drug levels.