How Long Is Too Long? The Prespiked Intravenous Debate.

BACKGROUND: As the number of operative cases increases, there is a greater emphasis on reducing inefficiency while maintaining patient safety. Recently, the issue of prespiking intravenous (IV) bags was raised. No study has assessed whether the risk of infection is related to the length of time a sterile (IV) fluid bag has been spiked. After completion of a pilot study revealed no microbial growth within 24 hours of an IV spike, a larger formal study was undertaken to determine whether there was an increased infection risk within 4 hours of spiking an intravenous fluid bag. METHODS: Five IV administration sets were spiked and hung in busy perioperative areas once a week for a 5-week period. Five samples were drawn from each IV set. Approximately 10 mL was collected per sample. All samples were inoculated in 2 separate growth media. If any growth was noted, the sample was marked as positive. RESULTS: A total of 125 samples were collected over a period of 5 weeks, yielding 250 specimens. No samples were excluded from the study. No growth was identified in any of the specimens. The 95% confidence interval was estimated to be 0, 0.063. DISCUSSION: There was no bacterial growth in prespiked normal saline IV bags in a perioperative environment. Thus, prespiking of normal saline IV bags in advance should pose no risk of infection to a patient if prepared within 4 hours.

Premedication with Intravenous Ibuprofen Improves Recovery Characteristics and Stress Response in Adults Undergoing Laparoscopic Cholecystectomy: A Randomized Controlled Trial.

OBJECTIVES: Examine the effect of preoperative dose of IV ibuprofen on stress response and postoperative recovery in laparoscopic cholecystectomy patients. DESIGN: Prospective, randomized, controlled, double-blind, multicenter trial. SETTING: Three university-based, tertiary care hospitals. SUBJECTS: Fifty-five adults, ASA 1, 2, or 3 scheduled for laparoscopic cholecystectomy were given a single preoperative dose of placebo or IV ibuprofen 800 mg. METHODS: Neurobehavioral assessments were evaluated preoperatively, in PACU, POD 1, and POD 3, using the 40-item Quality of Recovery questionnaire (QoR40), 9-item Modified Fatigue Severity Scale (MFSS), and 15-item Geriatric Depression scale (GDS). Blood samples were taken for cytokines (TNF-alpha, IL-1ß, IL-2, IL-6, IL-10, IFNγ), cortisol, CRP, epinephrine, and norepinephrine prior to the administration of study drug/placebo, intraoperatively, and after surgery. RESULTS: Global QoR40 scores remained at baseline for ibuprofen patients but significantly decreased in the placebo group. Severity of fatigue increased in patients receiving placebo but had no change with ibuprofen. The placebo group had lower GDS scores on POD 3. Epinephrine and norepinephrine were significantly lower intraoperatively for the ibuprofen group. Cortisol decreased postoperatively in the ibuprofen group. There was an impact of drug treatment on the immune response, as seen by an increase in TNFα and an increase in IL-10 when compared with placebo. CONCLUSIONS: Our results suggest the addition of NSAIDs may improve the overall quality of recovery, postsurgical fatigue, and early postoperative outcomes. Preoperative administration of IV ibuprofen modulates the stress and inflammatory response, as demonstrated by a decrease in the level of catecholamines, cortisol, and cytokines. TRIAL REGISTRATION: Clinicaltrials.gov identifier: 01938040.

Massive Ameloblastoma Requiring Awake Nasal Fiberoptic Intubation.

Ameloblastomas are rare tumors that arises from the odontogenic epithelium. Although benign and slow growing, an extensive lesion may cause airway obstruction, making bag-mask ventilation and intubation a significant challenge. Here, we present a 54-year-old male in respiratory distress with an 18x15x13 cm submandibular mass causing airway compromise. The tumor was extensive, occupying most of the oral cavity. Unable to perform direct laryngoscopy because of the tumor burden, we performed an awake nasal fiberoptic intubation to secure the airway. Successful intubation was achieved as well as subsequently tracheostomy. We subsequently provide a discussion on associated challenges and management options for patients with ameloblastomas.

Pulseless electrical activity during electroconvulsive therapy: a case report.

BACKGROUND: Arrhythmias resulting in cardiac arrest during electroconvulsive therapy have been reported. Most reported cases of cardiac arrest had asystole as the initial rhythm. Pulseless electrical activity as an initial rhythm of cardiac arrest during electroconvulsive therapy has never been reported. Also, thromboembolism after inflation of pneumatic tourniquet during lower limb surgery has been reported but never following tourniquet inflation during an electroconvulsive therapy. CASE PRESENTATION: We report a case involving an 81- year- old female who presented to us for an electroconvulsive therapy for severe depression and developed pulseless electrical activity immediately after electroconvulsive therapy. She was successfully resuscitated and was later found to have bilateral pulmonary emboli with a complete occlusion of the right lower lobe pulmonary artery. The source of embolus was from her left lower extremity deep venous thrombus, which we believe, got dislodged intraoperatively after inflation of pneumatic tourniquet. Our patient not only survived the massive pulmonary embolus, but also showed significant improvement in her mental status compared to her pre-admission level at the time of discharge to a sub-acute rehabilitation centre. CONCLUSION: We recommend that patients who are elderly and at high risk of thromboembolism should selectively undergo a preoperative doppler ultrasound for deep venous thrombosis. Also, selective application of tourniquet in the upper limb, to monitor for seizure activity, would reduce the incidence of pulmonary thrombo-embolism as embolic events are significantly less from deep venous thromboses of upper extremities when compared to lower extremities.

Comparison of the potency of lidocaine and chloroprocaine in sciatic nerve block in Sprague-Dawley rats.

AIM: This study investigates the relative potencies and ED(50) of the local anesthetics lidocaine and chloroprocaine in a sciatic block in Sprague-Dawley rats. METHODS: The study involved 80 rats (chloroprocaine n = 40, lidocaine n = 40). Each rat was injected close to the sciatic nerve with 0.1 ml of the concentration of local anesthetic being tested. Using the up-and-down allocation technique, the next concentration was determined by the response of the previous subject to a higher or lower concentration. A successful block was assessed by pinching the fifth metatarsal. Absent vocalization and a very weak withdrawal response were defined as the onset of block. RESULTS: Using the up-and-down methodology, the estimates of ED(50) for chloroprocaine was 0.1 ml of 1.2% (with 95% CI of 1.1-1.6), and that for lidocaine was 0.1 ml of 0.65% (with 95% CI of 0.65-0.88), giving a lidocaine/chloroprocaine potency ratio of 1.85 (with 95% CI of 1.66-2.61). DISCUSSION: Using the results of this study, the effects of the two drugs can be compared using the commercially available concentrations of chloroprocaine and lidocaine in a peripheral nerve block.

Alginate encapsulation for bupivacaine delivery and mesenchymal stromal cell immunomodulatory cotherapy.

PURPOSE: Mesenchymal stromal cells (MSCs) are used to treat various inflammatory conditions. In parallel, to mitigate pain associated with inflammation, analgesics or opioids are prescribed, often with significant side effects. Local anesthetics (LAs) offer a promising alternative to these medications. However, their short duration and negative effects on anti-inflammatory MSCs have limited their therapeutic effectiveness. To mitigate these negative effects and to move toward developing a cotherapy, we engineered a sustained release bupivacaine alginate-liposomal construct that enables up to 4 days of LA release. By encapsulating MSC in alginate (eMSC), we demonstrate that we can further increase drug concentration to clinically relevant levels, without compromising eMSC viability or anti-inflammatory function. MATERIALS AND METHODS: MSCs were freely cultured or encapsulated in alginate microspheres ± TNFα/IFN-γ and were left untreated or dosed with bolus, liposomal, or construct bupivacaine. After 24, 48, and 96 hours, the profiles were assessed to quantify secretory function associated with LA-MSC interactions. To approximate LA exposure over time, a MATLAB model was generated. RESULTS: eMSCs secrete similar levels of IL-6 and prostaglandin E2 (PGE2) regardless of LA modality, whereas free MSCs secrete larger amounts of IL-6 and lower amounts of anti-inflammatory PGE2. Modeling the system indicated that higher doses of LA can be used in conjunction with eMSC while retaining eMSC viability and function. In general, eMSC treated with higher doses of LA secreted similar or higher levels of immunomodulatory cytokines. CONCLUSION: eMSCs, but not free MSC, are protected from LA, regardless of LA modality. Increasing the LA concentration may promote longer and stronger pain mitigation while the protected eMSCs secrete similar, if not higher, immunomodulatory cytokine levels. Therefore, we have developed an approach, using eMSC and the LA construct that can potentially be used to reduce pain as well as improve MSC anti-inflammatory function.

A randomized, prospective, double-blind trial comparing 3% chloroprocaine followed by 0.5% bupivacaine to 2% lidocaine followed by 0.5% bupivacaine for interscalene brachial plexus block.

BACKGROUND: The combination of 2-chloroprocaine and bupivacaine (C/B) for regional anesthesia has been described, but its use was largely abandoned due to equivocal results in efficacy. In this prospective, double-blind, randomized study, we compared the onset of an interscalene block using C/B versus a combination of lidocaine and bupivacaine (L/B). METHODS: Thirty patients scheduled for shoulder arthroscopy under interscalene block were divided into two groups of 15 each. One group (C/B) received 3% 2-chloroprocaine combined with bicarbonate and epinephrine, immediately followed by 0.5% bupivacaine and epinephrine, whereas the other group (L/B) received 2% lidocaine instead of 3% 2-chloroprocaine. Motor and sensory block were assessed every 15 s. The primary end-point was the time of onset to complete motor block. Time-to-event (survival) statistical analysis tests were applied. RESULTS: One L/B patient had a failed block, and was excluded. The median time to motor block for C/B and L/B was 90 (15-575) and 180 (15-3720) s, respectively (P = 0.0325), and to sensory block for C/B and L/B was 90 (30-600) and 210 (30-3900) s, respectively (P = 0.0185). Survival analysis showed that in 5 min, 13 of 15 patients from the C/B group but only 7 of 14 from the L/B group had a successful motor block. In 10 min, 15 of 15 patients from the C/B group but only 10 of 14 from the L/B group had a successful motor block. It took as long as 60 min to assess block success/failure for blocks in the L/B group. CONCLUSIONS: This study demonstrates that a successful block was more rapid using C/B than L/B for interscalene blocks.

Alginate-liposomal construct for bupivacaine delivery and MSC function regulation.

Mesenchymal stromal cell (MSC) therapies have become potential treatment options for multiple ailments and traumatic injuries. In the clinical setting, MSC are likely to be co-administered with local anesthetics (LA) which have been shown to have dose- and potency-dependent detrimental effects on the viability and function of cells. We previously developed and characterized a sustained-release LA delivery formulation comprised of alginate-encapsulated liposomal bupivacaine. The current studies were designed to evaluate the effect of this formulation on the secretion of three key MSC regulatory molecules, interleukin 6 (IL-6), prostaglandin E2 (PGE2), and transforming growth factor-beta 1 (TGF-ß1). MSCs were treated with several bupivacaine formulations-bolus, liposome, or alginate-liposome construct (engineered construct)-in the presence or absence of inflammatory stimulus to stimulate an injured tissue environment. Our results indicated that compared to bolus or liposomal bupivacaine, the engineered construct preserved or promoted MSC anti-inflammatory PGE2 secretion; however, the engineered construct did not increase TGF-ß1 secretion. Bupivacaine release profile analyses indicated that mode of drug delivery controlled the LA concentration over time and pathway analysis identified several shared and cytokine-specific molecular mediators for IL-6, PGE2, and TGF-ß1 which could explain differential MSC secretion responses in the presence of bupivacaine. Collectively, these studies support the potential utility of alginate-encapsulated LA constructs for anti-inflammatory cell therapy co-administration and indicate that mode of local anesthetic delivery can significantly alter MSC secretome function.

Transtracheal 2-d ultrasound for identification of esophageal intubation.

This prospective, blinded, observational, efficacy study is one of the first to evaluate ultrasound in detecting esophageal intubation, a significant source of morbidity and mortality. We utilized a convenience sample of patients undergoing elective surgery during July 2004 in an urban teaching hospital. Trained Emergency Physician sonographers performed transtracheal ultrasounds of intubations to identify esophageal intubation. In 35 of the 40 patients enrolled, there was intubation of the trachea, whereas esophageal intubation occurred in five patients. Sonographers correctly identified all five esophageal intubations, for a sensitivity of 100% (95% confidence interval [CI] 48-100). Ultrasound correctly identified 34 of 35 tracheal intubations and misidentified one resulting in a specificity of 97% (95% CI 90-100). It seems that transtracheal ultrasound may be an efficacious adjunct for detecting esophageal intubation.

The effect of local anesthetic on pro-inflammatory macrophage modulation by mesenchymal stromal cells.

Administering local anesthetics (LAs) peri- and post-operatively aims to prevent or mitigate pain in surgical procedures and after tissue injury in cases of osteoarthritis (OA) and other degenerative diseases. Innovative tissue protective and reparative therapeutic interventions such as mesenchymal stromal cells (MSCs) are likely to be exposed to co-administered drugs such as LAs. Therefore, it is important to determine how this exposure affects the therapeutic functions of MSCs and other cells in their target microenvironment. In these studies, we measured the effect of LAs, lidocaine and bupivacaine, on macrophage viability and pro-inflammatory secretion. We also examined their effect on modulation of the macrophage pro-inflammatory phenotype in an in vitro co-culture system with MSCs, by quantifying macrophage tumor necrosis factor (TNF)-α secretion and MSC prostaglandin E2 (PGE2) production. Our studies indicate that both LAs directly attenuated macrophage TNF-α secretion, without significantly affecting viability, in a concentration- and potency-dependent manner. LA-mediated attenuation of macrophage TNF-α was sustained in co-culture with MSCs, but MSCs did not further enhance this anti-inflammatory effect. Concentration- and potency-dependent reductions in macrophage TNF-α were concurrent with decreased PGE2 levels in the co-cultures further indicating MSC-independent macrophage attenuation. MSC functional recovery from LA exposure was assessed by pre-treating MSCs with LAs prior to co-culture with macrophages. Both MSC attenuation of TNF-α and PGE2 secretion were impaired by pre-exposure to the more potent bupivacaine and high dose of lidocaine in a concentration-dependent manner. Therefore, LAs can affect anti-inflammatory function by both directly attenuating macrophage inflammation and MSC secretion and possibly by altering the local microenvironment which can secondarily reduce MSC function. Furthermore, the LA effect on MSC function may persist even after LA removal.

Effect of Local Anesthetics on Human Mesenchymal Stromal Cell Secretion.

Anti-fibrotic and tissue regenerative mesenchymal stromal cell (MSC) properties are largely mediated by secreted cytokines and growth factors. MSCs are implanted to augment joint cartilage replacement and to treat diabetic ulcers and burn injuries simultaneously with local anesthetics, which reduce pain. However, the effect of anesthetics on therapeutic human MSC secretory function has not been evaluated. In order to assess the effect of local anesthetics on the MSC secretome, a panel of four anesthetics with different potencies - lidocaine, procaine, ropivacaine and bupivacaine - was evaluated. Since injured tissues secrete inflammatory cytokines, the effects of anesthetics on MSCs stimulated with tumor necrosis factor (TNF)-α and interferon (IFN)-γ were also measured. Dose dependent and anesthesia specific effects on cell viability, post exposure proliferation and secretory function were quantified using alamar blue reduction and immunoassays, respectively. Computational pathway analysis was performed to identify upstream regulators and molecular pathways likely associated with the effects of these chemicals on the MSC secretome. Our results indicated while neither lidocaine nor procaine greatly reduced unstimulated cell viability, ropivacaine and bupivacaine induced dose dependent viability decreases. This pattern was exaggerated in the simulated inflammatory environment. The reversibility of these effects after withdrawal of the anesthetics was attenuated for TNF-α/IFN-γ-stimulated MSCs exposed to ropivacaine and bupivacaine. In addition, secretome analysis indicated that constitutive secretion changes were clearly affected by both anesthetic alone and anesthetic plus TNFα/IFNγ cell stimulation, but the secretory pattern was drug specific and did not necessarily coincide with viability changes. Pathway analysis identified different intracellular regulators for stimulated and unstimulated MSCs. Within these groups, ropivacaine and bupivacaine appeared to act on MSCs similarly via the same regulatory mechanisms. Given the variable effect of local anesthetics on MSC viability and function, these studies underscore the need to evaluate MSC in the presence of medications, such as anesthetics, that are likely to accompany cell implantation.

Typing skills of physicians in training.

BACKGROUND: There is an increasing use of electronic health records in hospitals across the United States. The speed and accuracy of residents in documenting electronic health records has been insufficiently addressed. METHODS: We studied resident typing skills at New York Methodist Hospital. Participating residents typed a standard 100-word alphanumerical paragraph of a patient's medical history. Typing skills were assessed by calculating the net words per minute (WPM). Typing skills were categorized as follows: (1) fewer than 26 net WPM as very slow; (2) 26 to 35 net WPM as slow; (3) 35 to 45 net WPM as intermediate; and (4) greater than 45 net WPM as fast. Residents were further categorized into (1) American medical graduates; (2) American international medical graduates; and (3) non-American international medical graduates. RESULTS: A total of 104 of 280 residents (37%) participated in the study. There was equal representation from various specialties, backgrounds, and all postgraduate levels of training. The median typing speed was 30.4 net WPM. Typing skills were very slow (34 of 104, 33%), slow (28 of 104, 27%), intermediate (29 of 104, 28%), and fast (13 of 104, 12%) among the residents. Typing skills of non-American international medical graduates (mean net WPM of 25.9) were significantly slower than those of American medical graduates (mean net WPM of 35.9) and American international medical graduates (mean net WPM of 33.5). CONCLUSIONS: Most residents (60%, 62 of 104) who participated in the study at our institute lacked typing skills. As the use of electronic health records increases, a lack of typing skills may impact residents' time for learning and patient care.

Efficacy of ginger on intraoperative and postoperative nausea and vomiting in elective cesarean section patients.

OBJECTIVE: To evaluate the efficacy of dry powdered ginger, given orally, on nausea and vomiting during and after an elective cesarean section performed under combined spinal epidural anesthesia. STUDY DESIGN: 239 women, ginger (n=116) and placebo (n=123), who underwent elective cesarean section at term under combined spinal-epidural anesthesia were provided with standard preoperative antiemetic treatment in addition to a randomized study drug. They were given two capsules (1g each) of either dry powdered ginger or placebo, one capsule a half-hour before induction of anesthesia and the second 2h after surgery. The study was double-blinded and the incidences of nausea and vomiting were assessed both intraoperatively and postoperatively. Levels of pain and pruritus were also assessed postoperatively. RESULTS: The intraoperative incidence of nausea was 52% and 61%, ginger versus placebo (p=0.149). The number of episodes of intraoperative nausea was less in the ginger group compared to placebo (mean difference was -0.396, 95% CI -0.738, -0.054) and the result was statistically significant (p=0.023). The incidence of intraoperative vomiting was 27.35% in the ginger group and 36.59% in the placebo group, and the difference was not statistically significant (p=0.126). The number of episodes of vomiting during surgery was less in the ginger group compared to placebo: (mean difference -0.158, 95% CI -0.626, 0.311) although statistically insignificant (p=0.505). Furthermore, postoperatively, there was no statistical difference in the incidence of nausea and vomiting assessed at 0, 2, 2 ½ and 24h after surgery. There were also no differences in postoperative pain or pruritus. CONCLUSION: Ginger given in dry powdered form reduced the number of episodes of intraoperative nausea compared to a placebo, but it had no effect on incidence of nausea, vomiting, or pain during and after an elective cesarean section performed under combined spinal epidural anesthesia.

Intraoperatively Diagnosed Tracheal Tear after Using an NIM EMG ETT with Previously Undiagnosed Tracheomalacia.

Tracheal rupture is a rare complication of endotracheal intubation. We present a case of tracheal rupture that was diagnosed intraoperatively after the use of an NIM EMG endotracheal tube. A 66-year-old female with a recurrent multinodular goiter was scheduled for total thyroidectomy. Induction of anesthesia was uncomplicated. Intubation was atraumatic using a 6 mm NIM EMG endotracheal tube (ETT). Approximately 90 minutes into the surgery, a tracheal tear was suspected. After confirming the diagnosis, conservative treatment with antibiotic coverage was favored. The patient made a full recovery with no complications. Diagnosis of the tracheal tear was made intraoperatively, prompting early management.

Propofol induces MAPK/ERK cascade dependant expression of cFos and Egr-1 in rat hippocampal slices.

BACKGROUND: Propofol is a commonly used intravenous anesthetic agent, which produce rapid induction of and recovery from general anesthesia. Numerous clinical studies reported that propofol can potentially cause amnesia and memory loss in human subjects. The underlying mechanism for this memory loss is unclear but may potentially be related to the induction of memory-associated genes such as c-Fos and Egr-1 by propofol. This study explored the effects of propofol on c-Fos and Egr-1 expression in rat hippocampal slices. FINDINGS: Hippocampal brain slices were exposed to varying concentrations of propofol at multiple time intervals. The transcription of the immediate early genes, c-Fos and Egr-1, was quantified using quantitative reverse transcriptase polymerase chain reaction (qRT-PCR). MAPK/ERK inhibitors were used to investigate the mechanism of action. We demonstrate that propofol induced the expression of c-Fos and Egr-1 within 30 and 60 min of exposure time. At 16.8 muM concentration, propofol induced a 110% increase in c-Fos transcription and 90% decrease in the transcription of Egr-1. However, at concentrations above 100 muM, propofol failed to induce expression of c-Fos but did completely inhibit the transcription of Egr-1. Propofol-induced c-Fos and Egr-1 transcription was abolished by inhibitors of RAS, RAF, MEK, ERK and p38-MAPK in the MAPK/ERK cascade. CONCLUSIONS: Our study shows that clinically relevant concentrations of propofol induce c-Fos and down regulated Egr-1 expression via an MAPK/ERK mediated pathway. We demonstrated that propofol induces a time and dose dependant transcription of IEGs c-Fos and Egr-1 in rat hippocampal slices. We further demonstrate for the first time that propofol induced IEG expression was mediated via a MAPK/ERK dependant pathway. These novel findings provide a new avenue to investigate transcription-dependant mechanisms and suggest a parallel pathway of action with an unclear role in the activity of general anesthetics.

Propofol induces ERK-dependant expression of c-Fos and Egr-1 in neuronal cells.

This study explored the effects of propofol on c-Fos and Egr-1 in neuroblastoma (N2A) cells. We demonstrate that propofol induced the expression of c-Fos and Egr-1 within 30 and 60 min of exposure time. At 16.8 microM concentration, propofol induced a 6 and 2.5-fold expression of c-Fos and Egr-1, respectively. However, at concentrations above 100 microM, propofol failed to induce expression of c-Fos or Egr-1. Propofol-induced c-Fos and Egr-1 transcription was unaffected by bicuculline, a gamma-aminobutyric acid-A receptor antagonist, but was abolished by PD98059, a mitogen-activated protein kinase/extracellular signal-regulated kinase inhibitor. Our study shows that clinically relevant concentrations of propofol induce c-Fos and Egr-1 expression through an extracellular signal-regulated kinase mediated and gamma-aminobutyric acid-A independent pathway.

Bicarbonate plus epinephrine shortens the onset and prolongs the duration of sciatic block using chloroprocaine followed by bupivacaine in sprague-dawley rats.

BACKGROUND: Chloroprocaine is a fast-acting local anesthetic, whereas bupivacaine is a long-acting one. They have been coadministered with limited success. The objective of this study was to determine the effect of additives on the efficacy of regional blockade using chloroprocaine followed by bupivacaine. METHODS: Four groups of Sprague-Dawley rats, 20 each, were administered chloroprocaine followed by bupivacaine to induce sciatic nerve blockade. Group 1 received chloroprocaine with isotonic sodium chloride solution followed by bupivacaine and was used as a control. Group 2 received chloroprocaine with isotonic sodium chloride solution and epinephrine followed by bupivacaine with epinephrine. Group 3 received chloroprocaine with sodium bicarbonate followed by bupivacaine, and group 4 received chloroprocaine with sodium bicarbonate and epinephrine followed by bupivacaine with epinephrine. The time to onset and duration of anesthesia were measured for all 4 groups. RESULTS: The block using chloroprocaine followed by bupivacaine in group 1 had an onset of 2.5 mins (SD, 0.4 mins) and duration of 104 mins (SD, 16 mins). Adding epinephrine to both chloroprocaine and bupivacaine (group 2) did not significantly change the onset (2.8 mins [SD, 1.3 mins]; P = 0.35) or duration (110 mins [SD, 25 mins]; P = 0.23). With group 3, adding bicarbonate to chloroprocaine hastened the onset (1.2 mins [SD, 0.4 mins]; P < 0.0001) and shortened the duration (87 mins [SD, 13 mins]; P = 0.008). In group 4, adding bicarbonate and epinephrine to chloroprocaine and epinephrine to bupivacaine hastened the onset (1.4 mins [SD, 0.4 mins]; P < 0.0001) and increased the duration (130 mins [SD, 23 mins]; P < 0.0001). CONCLUSIONS: Sodium bicarbonate plus epinephrine shortens the onset and prolongs the duration of a chloroprocaine-bupivacaine sciatic block in Sprague-Dawley rats.