Spinal 2-chloroprocaine: a comparison with lidocaine in volunteers

Subarachnoid lidocaine has been the anesthetic of choice for outpatient spinal anesthesia. However, its use is associated with transient neurologic symptoms (TNS). Preservative-free formulations of 2-chloroprocaine are now available and may compare favorably with lidocaine for spinal anesthesia. In this double-blinded, randomized, crossover study, we compared spinal chloroprocaine and lidocaine in 8 volunteers, each receiving 2 spinal anesthetics: 1 with 40 mg 2% lidocaine and the other with 40 mg 2% preservative-free 2-chloroprocaine. Pinprick anesthesia, tolerance to transcutaneous electrical stimulation and thigh tourniquet, motor strength, and a simulated discharge pathway were assessed. Chloroprocaine produced anesthetic efficacy similar to lidocaine, including peak block height (T8 [T5-11] versus T8 [T6-12], P = 0.8183) and tourniquet tolerance (46 +/- 6 min versus 38 +/- 24 min, P = 0.4897). Chloroprocaine anesthesia resulted in faster resolution of sensory (103 +/- 13 min versus 126 +/- 16 min, P = 0.0045) and more rapid attainment of simulated discharge criteria (104 +/- 12 min versus 134 +/- 14 min, P = 0.0007). Lidocaine was associated with mild to moderate TNS in 7 of 8 subjects; no subject complained of TNS with chloroprocaine (P = 0.0004). We conclude that the anesthetic profile of chloroprocaine compares favorably with lidocaine. Reliable sensory and motor blockade with predictable duration and minimal side effects make chloroprocaine an attractive choice for outpatient spinal anesthesia. IMPLICATIONS: The spinal anesthetic profile of chloroprocaine (40 mg) compares favorably with the same dose of spinal lidocaine. Reliable sensory and motor blockade with predictable duration and minimal side effects and without signs of transient neurological symptoms make chloroprocaine an attractive choice for outpatient spinal anesthesia.     

Spinal 2-chloroprocaine: a comparison with small-dose bupivacaine in volunteers

Ambulatory surgery continues to increase nationwide. Because spinal lidocaine is associated with transient neurologic symptoms, many clinicians have switched to small-dose bupivacaine for outpatient spinal anesthesia. However, bupivacaine often produces inadequate surgical anesthesia and has an unpredictable duration. Preservative-free 2-chloroprocaine (2-CP) has reemerged as an alternative for outpatient spinal anesthesia. We designed this double-blind, randomized, crossover, volunteer study to compare 40 mg of 2-CP with small-dose (7.5 mg) bupivacaine with measures of pinprick anesthesia, motor strength, tolerance to tourniquet and electrical stimulation, and simulated discharge criteria. Peak block height (2-CP average T7 [range T3-10]; bupivacaine average T9 [range T4-L1]), regression to L1 (2-CP 64 +/- 10 versus bupivacaine 87 +/- 41 min), and tourniquet tolerance (2-CP 52 +/- 11 versus bupivacaine 60 +/- 27 min) did not differ between drugs (P = 0.15, 0.12, and 0.40, respectively). However, time to simulated discharge (including time to complete block regression, ambulation, and spontaneous voiding) was significantly longer with bupivacaine (2-CP 113 +/- 14, bupivacaine 191 +/- 30 min, P = 0.0009). No subjects reported transient neurologic symptoms or other side effects. We conclude that spinal 2-CP provides adequate duration and density of block for ambulatory surgical procedures, and has significantly faster resolution of block and return to ambulation compared with 7.5 mg of bupivacaine.     

Spinal 2-chloroprocaine: minimum effective dose

BACKGROUND AND OBJECTIVES: Recent studies using preservative-free 2-chloroprocaine (2-CP) for spinal anesthesia have shown it to be a reliable short-acting agent in the 30-mg to 60-mg range. Investigations of doses below this range have not been performed. METHODS: To establish the minimum effective dose for spinal anesthesia, this randomized, double-blind, crossover study investigates the characteristics of spinal 2-CP 10 mg and 20 mg in 8 volunteers and compares the results with previous data obtained for 30 to 60 mg in the same human model. RESULTS: Peak block height, regression to L1, tolerance to tourniquet, and transcutaneous electrical stimulation all increased with increasing doses from 10 to 60 mg ( P <.0001). Likewise, time to complete block regression, ambulation, and micturition also increased with increasing spinal 2-CP dosage ( P <.0001). Degree of motor block generally increased with increasing doses from 10 to 60 mg; however, no differences existed between the 20-mg and 30-mg and between the 40-mg and 60-mg doses. CONCLUSIONS: Spinal 2-CP 40 mg and 60 mg provide rapid and reliable sensory and motor block. Although the 20-mg and 30-mg doses can produce sensory anesthesia adequate for brief surgical procedures, less motor block and some sacral sparing should be anticipated. Because the 10-mg dose produces only brief and inconsistent sensory anesthesia, it can be considered a no-effect dose.     

Spinal anesthesia: a comparison of procaine and lidocaine

PURPOSE: To compare spinal procaine to spinal lidocaine with regard to their main clinical characteristics and incidence of transient radicular irritation (TRI). METHODS: In this randomized, double-blind, prospective study, patients (two groups, n=30 each) received either 100 mg of lidocaine 5% in 7.5% glucose (Group L) or 100 mg of procaine 10% diluted with 1 ml cerebrospinal fluid (Group P). After spinal anesthesia, segmental level of sensory block was assessed by pinprick. Blood pressure and the height of the block were noted each minute for the first ten minutes, then every three minutes for the next 35 min and finally every five minutes until regression of the block to L4. Motor blockade was evaluated using the Bromage scale. To evaluate the presence of TRI, each patient was questioned 48 hr after surgery. RESULTS: Time to highest sensory level and to maximum number of segments blocked showed no difference between groups. Mean time for sensory regression to T10 and for regression of the motor block were shorter in Group P. Eighty minutes following injection, sensory levels were lower in Group P. Five patients had inadequate surgical anesthesia in Group P and only one in Group L. No patient in Group P had TRI (95% CI 10-12%) while eight (27%) in Group L did (95% CI 12-46%). CONCLUSIONS: Procaine 10% was associated with a clinical failure rate of 14.2%. This characteristic must be balanced against an absence of TRI, which occurs more frequently with the use of lidocaine 5%.     

Spinal 2-chloroprocaine: the effect of added fentanyl

Chloroprocaine is being investigated as a possible replacement for spinal lidocaine. Adding fentanyl to lidocaine increases the quality of spinal anesthesia without prolongation of block. We report the characteristics of 2-chloroprocaine (2-CP) spinal anesthesia with or without fentanyl in 8 volunteers receiving 40 mg 2-CP with saline or 20 micro g fentanyl in a double-blinded, randomized, crossover manner. Spinal anesthesia was successful for all subjects with complete block regression, ambulation, and void by 110 min. Itching occurred in all subjects receiving fentanyl, though medication was not required. No subject reported signs of transient neurological symptoms. Peak block with fentanyl averaged T5 (T3-7) and without fentanyl T9 (L1-T4) (P = 0.005). Regression to L1 was 78 +/- 7 min with fentanyl and 53 +/- 19 min without fentanyl (P = 0.02). Tourniquet was tolerated for 51 +/- 8 min with fentanyl and for 34 +/- 14 min without fentanyl (P = 0.02). Complete regression of block occurred at 104 +/- 7 min with fentanyl and by 95 +/- 9 min without fentanyl (P = 0.02). We conclude that 2-CP spinal anesthesia provides rapid onset and adequate potency, giving it a positive profile for ambulatory surgery. The addition of fentanyl lengthens regression to L1 and tourniquet tolerance while minimally lengthening block duration. IMPLICATIONS: Spinal 2-chloroprocaine (40 mg) provides rapid onset and reliable blockade without signs of transient neurological symptoms, giving it a positive profile for ambulatory surgical settings. The addition of fentanyl appears to lengthen the regression to L1 dermatome and tourniquet time while minimally lengthening duration of block.     

Spinal 2-chloroprocaine: the effect of added clonidine

Preservative-free 2-chloroprocaine (2-CP) is being investigated for short-acting spinal anesthesia. Clonidine improves the quality of spinal bupivacaine and ropivacaine, but in traditional doses (1-2 microg/kg) it produces systemic side effects. It has not been studied in combination with 2-CP. In this double-blind, randomized crossover study, we compared spinal 2-CP (30 mg) with and without clonidine (15 microg) in eight volunteers. Pinprick anesthesia, motor strength, tolerance to electrical stimulation and thigh tourniquet, and time to ambulation were assessed. Peak block height was similar between 2-CP (T8 [range, T6 to L2]) and 2-CP with clonidine (T8 [range, T4 to T11]) (P = 0.57). Sensory anesthesia was prolonged with clonidine at L1 (51 +/- 23 min versus 76 +/- 11 min; P = 0.002), as was complete block regression (99 +/- 18 min versus 131 +/- 15 min; P = 0.001). Lower extremity motor blockade was increased with clonidine (return to baseline Bromage score: 65 +/- 13 min versus 79 +/- 19 min, P = 0.004; return to 90% gastrocnemius strength: P = 0.003). Clonidine increased tourniquet tolerance from 33 to 45 min (P = 0.06) and increased time to ambulation, spontaneous voiding, and discharge (99 +/- 18 min versus 131 +/- 15 min for all; P = 0.001). There were no differences in hemodynamic measurements, and no subject reported transient neurologic symptoms. We conclude that small-dose clonidine increases the duration and improves the quality of 2-CP spinal anesthesia without systemic side effects.     

Spinal 2-chloroprocaine: effective dose for ambulatory surgery

Background: There is an interest in finding a safe, short-acting spinal anaesthetic, suitable for ambulatory surgery. In this prospective study, we evaluated the effective dose of plain 2-chloroprocaine (2-CP) for lower limb surgery, including knee arthroscopy and saphenectomy.
Methods: Sixty-four ASA physical status I–III patients undergoing elective lower limb surgery were randomly allocated to one of the four local anaesthetic groups for spinal anaesthesia in a double-blind manner. The patients ( n =16 patients in each group) received 35, 40, 45 or 50 mg of 10 mg/ml isobaric 2-CP.
Results: In all patients, anaesthesia was sufficient for the planned surgery. The median peak block height (T9) was similar in all four groups ( P =0.66). Time to complete sensory block regression was faster in the 35 mg group (111 min, mean) and in the 40 mg group (108 min) than in the 50 mg group (134 min, P =0.005). No differences in time to complete motor block regression were observed ( P =0.3). Home discharge time was faster in the 35 mg group (123 min) and in the 40 mg group (122 min) than in the 50 mg group (165 min, P =0.001). No complications related to spinal anaesthesia were observed and no transient neurologic symptoms (TNS) were reported at the 3-day follow-up.
Conclusion: Spinal 2-CP, 10 mg/ml 35, 40, 45 and 50 mg provide reliable sensory and motor block for ambulatory surgery, while reducing the dose of 2-CP to 35 and 40 mg resulted in a spinal block of faster ambulation.     

Spinal 2-chloroprocaine: the effect of added dextrose

Spinal 2-chloroprocaine is being investigated as an alternative short-acting spinal anesthetic to replace lidocaine for outpatient surgery. Adding dextrose increases the baricity of solutions and alters the characteristics of spinal anesthesia. In this study, we compared 2-chloroprocaine spinal anesthesia performed with or without the addition of dextrose (1.1%). Eight volunteers underwent 2 spinal anesthetics, receiving 40 mg 2-chloroprocaine (2 mL, 2%) with 0.25 mL saline with one and 0.25 mL 10% dextrose with the other in a double-blinded, randomized, balanced crossover manner. Pinprick anesthesia, tolerance to transcutaneous electrical stimulation, and tourniquet, motor strength measurements, and time to ambulation and void were assessed. Postvoid residual bladder volume was measured via ultrasound. Spinal anesthesia was successful in all subjects and regressed within 110 (80-110) min. There was no significant difference in peak height T4 (T7-C6), time to achieve peak block height (14 +/- 6 min), time for 2-segment regression (44 +/- 9 min), regression to L1 (66 +/- 12 min), tolerance of tourniquet (43 +/- 9 min), or return of motor function (81 +/- 14 min). Mean postvoid residual volume was larger with dextrose (74 +/- 67 mL versus 16 +/- 35 mL; P = 0.02). No subject reported signs of transient neurologic symptoms (TNS). In conclusion, spinal 2-chloroprocaine provides adequate potency with reliable regression, seemingly without TNS. Adding dextrose does not significantly alter spinal block characteristics but increases residual bladder dysfunction. Therefore, the addition of glucose to 2-chloroprocaine for spinal anesthesia is not necessary. IMPLICATIONS: Spinal chloroprocaine provides adequate potency with reliable regression, seemingly without concerns of transient neurologic symptoms, and hence an appealing profile for outpatient surgery. The addition of dextrose does not alter peak block height or tolerance of thigh tourniquet, and increases the degree of residual bladder dysfunction.     

Spinal 2-chloroprocaine: a dose-ranging study and the effect of added epinephrine

With the availability of preservative- and antioxidant-free 2-chloroprocaine (2-CP), there may be an acceptable short-acting alternative to lidocaine for spinal anesthesia. We examined the safety, dose-response characteristics, and effects of epinephrine with spinal 2-CP. Six volunteers per group were randomized to receive 30, 45, or 60 mg of spinal 2-CP with and without epinephrine. Intensity and duration of sensory and motor blockade were assessed. When 11 of the 18 volunteers complained of vague, nonspecific flu-like symptoms, breaking of the blind revealed that all spinal anesthetics associated with the flu-like symptoms contained epinephrine. There were no complaints of flu-like symptoms in the volunteers who received 2-CP without epinephrine. No further spinal anesthetics containing epinephrine were administered, resulting in 29 anesthetics (11 with epinephrine, 18 without epinephrine.) Plain 2-CP demonstrated a dose-dependent increase in peak block height and duration of effect at all variables except time to 2-segment regression and time to regression to T10. Time to complete sensory regression with plain 2-CP was 98 +/- 20, 116 +/- 15, and 132 +/- 23 min, respectively. 2-CP with epinephrine produced times to complete sensory regression of 153 +/- 25, 162 +/- 33, and 148 +/- 29 min, respectively. Preservative and antioxidant free 2-CP can be used effectively for spinal anesthesia in doses of 30-60 mg. Epinephrine is not recommended as an adjunct because of the frequent incidence of side effects. IMPLICATIONS: Hyperbaric spinal 2-chloroprocaine is effective and has an anesthetic profile appropriate for use in the surgical outpatient over the dose range of 30-60 mg without signs of transient neurologic symptoms. The addition of epinephrine is not recommended because of the frequent incidence of side effects.     

Spinal 2-chloroprocaine for surgery: an initial 10-month experience

Spinal 2-chloroprocaine (2-CP) is currently being investigated as a short-acting alternative to lidocaine, which frequently causes transient neurologic symptoms (TNS) in surgical patients. TNS has not been reported with 2-CP in volunteers in doses ranging from 30 to 60 mg and appears to provide an excellent level of surgical anesthesia. In this retrospective study, we describe the experience with spinal 2-CP in surgical patients during its first 10 mo of clinical use at our institution. Most patients had ambulatory surgery, including 39 orthopedic, 30 general surgical, 18 gynecologic, and 34 genitourinary procedures. Chloroprocaine 30 or 40 mg, with or without fentanyl (10-20 microg), was the most common (92%) dose combination used. Mean peak block height averaged T6 to T8. The surgical procedure time was 32.3 +/- 18.4 min. Time from placement of the block to the end of the surgical procedure was 53.1 +/- 20.7 min. Times to ambulation and discharge were 155.1 +/- 34.7 min and 207.9 +/- 69.4 min, respectively. 2-CP spinal anesthesia has proven to be a safe and effective alternative to lidocaine and procaine for ambulatory surgical procedures of < or =1 h, with a predictable regression of block height. No patients reported TNS after surgery.     

Paracervical block with 2-chloroprocaine

Thirty healthy term gravidas in active labor received a paracervical block (PCB) with the ester-type local anesthetic, 2-chloroprocaine (2CP). Good to excellent pain relief resulted in all but 1 case. The duration of action was short (mean 38.9 min), requiring repeat blocks in 6/30 cases. Fetal heart rate and uterine contractions were electronically monitored, and fetal acid-base status was periodically checked by fetal scalp pH measurements. PCB-related fetal bradycardia was observed in 3 cases, but in only 1 case was PCB the only cause for the bradycardia. Fetal acidosis was not observed. No instance of neonatal depression or acidosis as expressed by the 1- and 5-minute Apgar scores and cord blood acid-base evaluation was observed. No maternal complications were observed. It is concluded that paracervical block using 2CP is an effective though short-acting method of pain relief which, when properly monitored, is safe for both mother and fetus.     

Hospital discharge after ambulatory knee arthroscopy: A comparison of epidural 2-chloroprocaine versus lidocaine

BACKGROUND AND OBJECTIVES: This prospective, randomized, double-blind study compares the efficacy of epidural 2-chloroprocaine and lidocaine for attaining hospital discharge criteria after ambulatory knee arthroscopy. We hypothesized that 2-chloroprocaine would facilitate earlier discharge than lidocaine. METHODS: American Society of Anesthesiologists (ASA) I and II patients were randomized to receive equipotent doses of epidural 3% 2-chloroprocaine or 1.5% lidocaine, both without epinephrine. Time to block resolution and discharge were compared between groups, along with the need for epidural reinjection, surgical times, and postoperative back pain. RESULTS: Twenty-seven patients completed the study, 13 in the 2-chloroprocaine group and 14 in the lidocaine group. The 2-chloroprocaine group was ready for discharge significantly earlier than the lidocaine group (130 +/- 17 min [range, 105 to 160] v 191 +/- 32 min [range 144 to 251]; P <.0001, 90% power). The lidocaine group required more epidural reinjections. Anesthesia-related side effects were similar in both groups. CONCLUSIONS: Epidural 3% 2-chloroprocaine without epinephrine is an advantageous choice for ambulatory knee arthroscopy. It enables readiness for discharge an hour sooner than 1.5% lidocaine, requires fewer reinjection interventions, and may reduce delayed discharge secondary to prolonged time to void. This clinical study shows the superiority of epidural 3% 2-chloroprocaine over 1.5% lidocaine for expediting hospital discharge after ambulatory surgery.     

Hyperbaric spinal ropivacaine: a comparison to bupivacaine in volunteers

BACKGROUND: Ropivacaine is a newly introduced local anesthetic that may be a useful alternative to low-dose bupivacaine for outpatient spinal anesthesia. However, its relative potency to bupivacaine and its dose-response characteristics are unknown. This double-blind, randomized, crossover study was designed to determine relative potencies of low-dose hyperbaric spinal ropivacaine and bupivacaine and to assess the suitability of spinal ropivacaine for outpatient anesthesia. METHODS: Eighteen healthy volunteers were randomized into three equal groups to receive one spinal administration with bupivacaine and a second with ropivacaine, of equal-milligram doses (4, 8, or 12 mg) of 0.25% drug with 5% dextrose. The duration of blockade was assessed with (1) pinprick, (2) transcutaneous electrical stimulation, (3) tolerance to high tourniquet, (4) electromyography and isometric force dynamometry, and (5) achievement of discharge criteria. Differences between ropivacaine and bupivacaine were assessed with linear and multiple regression. P < 0.05 was considered significant. RESULTS: Ropivacaine and bupivacaine provided dose-dependent prolongation of sensory and motor block and time until achievement of discharge criteria (R2 ranges from 0.33-0.99; P values from < 0.001 through 0.01). Spinal anesthesia with ropivacaine was significantly different from bupivacaine and was approximately half as potent for all criteria studied. A high incidence of back pain (28%; P = 0.098) was noted after intrathecal ropivacaine was given. CONCLUSION: Ropivacaine is half as potent and in equipotent doses has a similar profile to bupivacaine with a higher incidence of side effects. Low-dose hyperbaric spinal ropivacaine does not appear to offer an advantage over bupivacaine for use in outpatient anesthesia.     

Spinal neurofibromas: a report of 66 cases and a comparison with meningiomas

A series of 66 spinal cord neurofibromas was analyzed for history, signs, surgical approach, and outcome. The tumors presented primarily with sensory symptoms. Plain films were abnormal in 1/2 of cases and 1/2 had a complete block. They were primarily intradural, and primarily thoracic. A conservative exam system was used for follow-up and 85% with pain had complete relief; 50% with motor loss had normal motor function, and 88% had normal sensation who had prior sensory loss. In comparison to meningiomas, the principal differences were that neurofibromas had an even sex distribution, a lower incidence of cord signs and symptoms, more frequent findings on plain x-rays, and higher cerebrospinal fluid protein. Surgical outcome was similar. Sacrifice of the involved root during removal usually did not produce a deficit. The series is compared with a similar series of meningiomas from the same institution over the same time period.     

Labor analgesia with epidural bupivacaine plus fentanyl: enhancement with epinephrine and inhibition with 2-chloroprocaine

Epidural injection of drug combinations may decrease toxicity by decreasing the dose of each component, but may also result in detrimental drug interactions. In this study interactions among bupivaciane, fentanyl, epinephrine, 2-chloroprocaine, and lidocaine for epidural analgesia during labor were examined. In part 1 of the study, healthy parturients received in a random manner either 10 ml of 0.25% bupivacaine with 5 micrograms/ml fentanyl (n = 50), or 10 ml of this combination with 3.33 micrograms/ml freshly added epinephrine (n = 50). Epinephrine prolonged the median duration of pain relief (180 vs. 138 min, P less than 0.05) without affecting duration of first or second stages of labor, or neonatal Apgar scores. Blood pressure decreased slightly more in those receiving epinephrine, although the incidence of hypotension requiring treatment did not differ between groups. Part 2 of the study evaluated the possibility that local anesthetic used for confirming catheter tip location may interfere with the analgesic action of this bupivacaine-fentanyl-epinephrine (BFE) combination. In 50 additional parturients, a test dose of either 2-chloroprocaine (n = 25) or lidocaine (n = 25) was injected through the epidural catheter and was followed by injection of the BFE mixture. The lidocaine test dose group had a greater duration of analgesia than the 2-chloroprocaine test dose group (median duration of 164 vs. 91 min, P less than 0.05). The authors conclude that the addition of epinephrine 3.33 micrograms/ml significantly increases the duration of analgesia obtained from 0.25% bupivacaine with 5 micrograms/ml fentanyl. However, prior injection of 2-chloroprocaine, but not lidocaine, significantly decreases the duration of analgesia achieved with this BFE mixture.     

Spinal procaine with and without epinephrine and its relation to transient radicular irritation

PURPOSE: To document the clinical characteristics of procaine with or without the addition of epinephrine. METHODS: In this randomized, prospective, double blind study, 62 patients received spinal anesthesia with 100 mg procaine and either 0.3 mg epinephrine (EPI group) or 0.3 ml NaCl 0.9% (SALINE group). Sensory anesthesia to needle prick was evaluated q 1 min for 10 min, q 3 min for 33 min and q 5 min until regression to L4. Motor block was assessed with the Bromage scale. Patients were questioned, by telephone, for transient radicular irritation (TRI) 48 hr later. RESULTS: Time to reach highest sensory level and number of segments blocked showed no difference. Mean time for regression of the sensory level to T10 was longer in EPI (83 +/- 23 vs 66 +/- 20 min, P < 0.01). Time to recuperate to full flexion of knees and feet (Bromage 4) was longer in EPI (126 +/- 37 vs 100 +/- 30 min, P < 0.01). Patients in EPI received more ephedrine. Eighteen patients had nausea (15 EPI/3 SALINE, P < 0.0015). One patient had TRI, incidence: 1.67%, 95% CI (< 1%-9%). CONCLUSION: Spinal procaine is appropriate for surgery of short duration. Epinephrine prolongs sensory and motor blocks by 25%. However, it is associated with a high incidence of nausea.