Multiport epidural catheters: does the air test work?

BACKGROUND: Multiport epidural catheters are popular; however, the reliability of the air test has not been evaluated with this catheter design. The authors determined the effectiveness of aspirating for blood and the air test in detecting intravascular multiorifice epidural catheters. METHODS: Three hundred women in labor underwent placement of a blunt-tip, three-hole, 20-gauge, lumbar epidural catheter. If there were no signs of spinal anesthesia, 3 ml lidocaine or bupivacaine was injected and the patient was observed for signs of spinal anesthesia. If there were no signs of spinal anesthesia, the authors injected 1 ml air through the epidural catheter while listening to the maternal precordium using a Doppler fetal heart rate monitor. Catheters through which blood was aspirated were air-tested and replaced. Patients with air-test-positive, blood-aspiration-negative catheters received 100 mg lidocaine through the catheter and were questioned about toxicity symptoms. The authors injected bupivacaine-fentanyl through aspiration-negative,air-test-negative catheters and recorded the sensory analgesic level 20 min later. RESULTS: The authors aspirated cerebrospinal fluid through one catheter and documented intravascular placement in 11 catheters. Results of the air test and blood aspiration were positive for eight catheters. Blood could not be aspirated from one air-test-positive catheter; perioral numbness developed in the patient after lidocaine injection. Blood was freely aspirated from two air-test-negative catheters. In the remaining 288 catheters, bupivacaine-fentanyl injection produced epidural analgesia in 279 patients and no effect in 9 patients. CONCLUSIONS: The authors obtained false-negative results with both catheter aspiration and the air test. Fractionating the local anesthetic dose is important when using multiorifice epidural catheters.     

Does pregnancy increase the efficacy of lumbar epidural anesthesia?

Pregnancy has been reported to enhance the sensitivity of nerves to local anesthetics and to decrease anesthetic requirements during regional anesthesia. In this study, whether pregnancy increased the efficacy of lumbar epidural anesthesia was evaluated. Two populations (14 pregnant and 14 non-pregnant women) undergoing lumbar epidural anesthesia were studied and received 17 mL of 2% lidocaine-epinephrine (1: 200,000). The pain threshold response after repeated electrical stimulation was used to assess sensory blockade at the L2, S1 and S3 dermatomes. Motor blockade was evaluated using the Bromage score. Demographic data except for weight were comparable between the two groups. There was a significant difference in cephalad spread of anesthesia between the groups. No significant differences in pain threshold or onset of sensory blockade at the L2, S1 or S3 segments were found between the groups. The pain thresholds at the S1 and S3 dermatomes were significantly lower than that at L2 within each group. The mean onset times at the S1 and S3 dermatomes were significantly longer than that at L2 within each group. No differences in Bromage score were found between the groups. In pregnant women, cephalad spread of epidural anesthesia was facilitated but latency of blockade, density and motor blockade were not. It takes over 25 min to achieve satisfactory blockade at sacral segments. Those who perform lumbar epidural anesthesia alone for cesarean section should consider the use of additives (e.g. fentanyl, bicarbonate) to enhance the block, or a greater volume of local anesthetic.     

Does the use of pulmonary artery catheters increase the number of organs available for transplantation?

Hadjizacharia P, Salim A, Brown C, Inaba K, Chan LS, Mascarenhas A, Margulies DR. Does the use of pulmonary artery catheters increase the number of organs available for transplantation?
Clin Transplant 2010: 24: 62–66. © 2009 John Wiley & Sons A/S. Abstract: Aggressive donor management, including the placement of a pulmonary artery catheter (PAC) to monitor hemodynamic status and tissue perfusion, has been associated with a significant increase in the number of organs recovered for transplantation. Nonetheless, there has been growing scrutiny over the use of PACs because of their known complications and lack of therapeutic effect. The purpose of this study is to evaluate the use of PACs in the management of organ donors. The records of all patients who successfully donated organs between January 1, 2002 and December 31, 2005 were reviewed. A total of 96 patients underwent successful organ donation during the four‐yr study period. Of these, 49 (51.0%) were managed with a PAC. Compared with donors managed without a PAC, there were significantly more hearts recovered from donors managed with a PAC (71.4% vs. 44.7%; p = 0.0079) with no difference in the daily administration of fluids and vasopressors between the two groups. The management of organ donors with a PAC can help maximize cardiac procurement.     

The electrical properties of epidural catheters: what are the requirements for nerve stimulation guidance?

We designed the present study to investigate the electrical resistance of commercially available epidural catheters and to search for products and procedures suitable for nerve stimulation-guided insertion. Four types of epidural catheters were evaluated: 2 nonwire-reinforced catheters (19-gauge and 20-gauge nylon) and 2 wire-reinforced catheters (19-gauge without stylet and 20-gauge with stylet). The resistance of a catheter was calculated from the voltage level proportional to the fixed resistance in series circuit. In case of physiologic saline, the resistance of nonreinforced catheters was more than 700 kOmega, whereas the wire-reinforced catheter was 14.4 +/- 0.20 kOmega without stylet and 10.1 +/- 0.42 kOmega with stylet. When the stylet was passed through a 20-gauge nylon catheter, the resistance decreased to 49.2 +/- 1.96 kOmega. When catheters were primed with 10% hypertonic saline, the resistance of both nonreinforced catheters decreased by one third compared with physiologic saline. The electrical resistance of the saline-filled epidural catheters significantly differed among products tested. We conclude that epidural catheterization that is guided by electrical stimulation should be performed only with catheters equipped with spiral stainless steel wire reinforcement or with a stainless steel stylet.     

Does the evidence support the use of spinal and epidural anesthesia for surgery?

When spinal and epidural anesthesia were introduced into clinical practice, their primary use was as an alternative to general anesthesia. Later, largely as a result of the realization that opioids could be safely and effectively used to produce selective spinal analgesia, spinal and epidural (neuraxial) analgesia began to be used specifically for the treatment of perioperative pain. We present a systematic review of the literature on neuraxial anesthesia and analgesia, new meta-analyses that illustrate the powerful effect of improvements in perioperative safety in general on the ability of neuraxial techniques to make a difference, and a consideration of why a literature analysis does not provide clear answers.     

Does epidural analgesia during labour affect the neonate?

Focus has changed from the immediate postpartum condition to the more long-term outcome of the neonate with respect to the use of epidural analgesia in labour. Anaesthesiologists have been slow to respond to the demand for this information. Newer analgesic agents and techniques may offer some advantage to the neonate; however, extensive study is still needed.     

Does epinephrine improve the diagnostic accuracy of aspiration during labor epidural analgesia?

Aspiration reliably detects almost all IV multiorifice epidural catheters. Although a supplemental epinephrine 15-microg test dose may detect the rare IV catheter that does not yield blood on aspiration, false-positive epinephrine responses may cause some women to unnecessarily undergo repeat epidural catheter insertion. We evaluated 532 consecutive eligible patients requesting neuraxial labor analgesia. Patients were excluded if they had a contraindication to epinephrine or if they received intrathecal sufentanil/bupivacaine. Multiorifice catheters were inserted 4-6 cm into the epidural space as part of an epidural (n = 305) or combined spinal-epidural (n = 270) technique. We used aspiration, a lidocaine/epinephrine test dose, and bolus injection or infusion of dilute bupivacaine/sufentanil solutions to systematically determine IV, intrathecal, or epidural catheter location. Aspiration alone detected 47 of 48 intravascular catheters. There were 10 positive epinephrine responses: 2 were true positives, 7 were falsely positive (subsequent local anesthetic injection/infusion produced bilateral sensory change and analgesia), and 1 catheter was removed without further testing. Aspiration detected almost all intravascular catheters. Although the epinephrine test dose did detect one catheter that proved to be in a blood vessel, 87.5% of positive responses occurred in women without intravascular catheters. IMPLICATIONS: Epidural catheters may enter a blood vessel. Many clinicians use epinephrine to detect these catheters. Because aspiration alone detects almost all IV multiorifice catheters in laboring women, a subsequent epinephrine test dose may be unnecessary.     

Does academic advancement impact teaching performance of surgical faculty?

BACKGROUND: An important reason for young surgeons entering academic practice is to educate trainees. As clinical and administrative responsibility increases, teaching time is decreased. We attempted to determine if the teaching performance of surgeons declines with career advancement. METHODS: Between July 1998 and June 2002, all faculty at our institution were evaluated by medical students on the surgical clerkship. Surgeons were scored on clinical teaching (CLINIC), operating room teaching (OR), and overall teaching (ALL) with the use of a 4-point scale. Surgeons were grouped by years in practice; group scores were compared with ANOVA. RESULTS: A total of 6345 evaluations were completed on 74 academic surgeons. Junior surgeons (< or = 5 years) performed better in operating room teaching (P < .001), clinical teaching (P<.001), and overall teaching (P < .001) compared with those in practice more than 5 years. When junior surgeons were compared with the most senior faculty (> or = 15 years), the difference in all categories was even greater (P < .001). Tenure status had no relationship to teaching ability. CONCLUSIONS: Junior faculty surgeons were perceived to be more effective teachers when compared to senior faculty. With career advancement, faculty may devote less energy to teaching and become less effective. Therefore, continued emphasis should be placed on strengthening education skills throughout the surgical career.     

Accidental dural puncture during epidural injection of corticosteroids: a different approach?

We report 6 cases diagnosed with accidental dural puncture after epidural injection of corticosteroids for low back pain. All the patients reported postdural puncture headache during their stay in the postanesthetic recovery unit. For 3 patients, pain resolved with treatment given in the recovery unit. Two other patients also required mild analgesics for 1 week. In the last patient, a blood patch was used to treat incapacitating headache 22 days after the epidural procedure and mild analgesics were needed for 4 more weeks. It is important to establish a protocol for treating postdural puncture headache in pain clinics to facilitate decision making. Good physician-patient communication is necessary to avoid refusals for permission for other epidural techniques and to facilitate management of symptoms.     

Does the use of low dose bupivacaine/opioid epidural infusion increase the normal delivery rate?

To investigate whether using low dose epidural infusion improves the normal delivery rate, outcome of labour was studied in women with singleton vertex presentations randomised to receive either 0.0625% bupivacaine opioid, or plain bupivacaine 0.125% for labour. The infusion rate was titrated to maintain analgesia and a sensory level to T10. Data were analysed using the unpaired t test, Mann-Whitney U test and for categorical variables chi2 test. Adjusted odds ratios for factors significantly associated with non-normal delivery were calculated using stepwise logistic regression. There were 291 women in the low dose and 296 in the plain bupivacaine group. There were no significant differences between groups in parity, race, induction of labour, use of augmentation, cervical dilatation at epidural insertion, duration of any stage of labour or duration or volume of infusion. Total dose of bupivacaine (126 +/- 47 mg versus 91 +/- 32 mg) and the proportion of women with motor block at the end of labour (45% versus 27%) were significantly greater in the plain bupivacaine than in the low dose group (P < 0.0001). The adjusted odds ratios (95% CI) for factors significantly associated with non-normal delivery were primiparity: 4.68 (2.78-7.88), older maternal age: 1.1 (1.05-1.14), longer active second stage of labour: 1.01 (1.005-1.017), total bupivacaine dose: 1.01 (1.005-1.016) and greater cervical dilatation at epidural insertion 1.22 (1.08-1.37). Treatment group and motor block at the end of labour had no significant effect. We found no increase in normal delivery rate with low dose infusions.     

Does epidural increase the incidence of cesarean delivery or instrumental labor in Saudi populations?

BACKGROUND: This is a retrospective review of the medical records of 861 patients admitted for vaginal delivery. Patients were randomized to either epidural analgesia or other analgesic methods of pain relief for labor pains. The primary purpose of this study was to evaluate the effect of epidural analgesia on the rate of cesarean section delivery. METHODS: 861 patients were admitted to Saad Specialist Hospital for vaginal delivery between May 1, to September 30, 2006. Patients were divided into Nulliparous (334 patients) and Multiparous (527 patients) populations. Each population was then divided into two groups, epidural and non-epidural group. Epidural analgesia was initiated by a bolus of bupivacaine 0.25% (6 to 10 ml) plus fentanyl (50 to 100 microg), followed by bupivacaine 0.125% plus fentanyl (1 to 2 microg/ml) at the rate of (6 to 12 ml/h). Non-epidural analgesia was initiated by one or mixture of I.M meperidine 50 to 100 mg I.M, promethazine hydrochloride 25 mg, or Ontonox inhalers. RESULTS: In the Nulliparous population a total of 57 patients requested epidural (the epidural gp), while 277 patients received other analgesic methods (the non-epidural gp). There was no difference in the rate of cesarean section deliveries between the two analgesia groups (12 patients of 57 in the epidural group (21.1%), versus 61 patients of 277 (22%) in the non-epidural gp). In the Multiparous population, a total of 49 patients requested epidural analgesia (epidural gp), while 478 patients received other analgesic methods (the non-epidural gp). There was no difference in the rate of cesarean section deliveries between the two analgesia groups (5 of 49 patients (10.2%) in the epidural group compared to 39 of 478 patients (8.2%) in the non-epidural gp). Significantly, more patients in the epidural group had forceps or vacuum assisted deliveries compared to the other analgesia group (the non-epidural gp). This was evident in both the Nulliparous population (7 of 57 patients in the epidural gp (12.3%) compared to 13 of 277 patients (4.7%) in the non-epidural gp, p<0.05), and in the Multiparous population (4 of 49 patients (8.2%) in the epidural gp versus only 6 of 478 patients (1.3%) in the non-epidural gp, p<0.005). Patients in the epidural gp had significantly lower pain scores compared to the other analgesia gp. Nulliparous reported lower pain scores during the first stage (epidural 2 +/- 2 vs non-epidural 5 +/- 4, p<0.0001) and second stage of labor (epidural 3 +/- 3 vs non-epidural 6 +/- 3, p<0.0001). Multiparous scores were (epidural 2 +/- 2 vs non-epidural 4 +/- 3, p<0.0001) in the first stage and (epidural 3 +/- 3 vs non-epidural 5 +/- 4, p = 0.0007) in the second stage. Higher satisfaction rates were reported in epidural groups versus the non-epidural groups. 80% of Nulliparous women who received epidural rated their satisfaction as excellent or good versus 45% in the non-epidural group p<0.001. In the Multiparous population 77% in the epidural versus 43% in the non-epidural groups p<0.001 reported excellent to good satisfaction rates. CONCLUSION: Epidural analgesia is an effective method of pain relief during labor compared to the other analgesic methods of labor pain relief, and it does not increase the incidence of cesarean section deliveries.