Multiorifice Epidural Catheter Research Articles

Direct Comparison of Peak Bulk Flow Rate of Programmable Intermittent Epidural Bolus and Manual Epidural Bolus Using a Closed-End Multiorifice Catheter: An Experimental Study.

The programmable intermittent epidural bolus (PIEB) has been popularized as the optimal delivery technique for labor analgesia. Suggested advantages of this method are less local anesthetic consumption, improved maternal satisfaction, potentially shorter duration of labor, and decreased workload requirements for the anesthesia providers. However, a manual bolus is still routinely used for breakthrough pain when the PIEB is underperforming. We conducted a laboratory-based study to quantify the flow through a multiorifice epidural catheter using the PIEB setting on an epidural pump compared to the manual epidural bolus. Four syringe volumes, 3, 5, 10, and 20 mL, were selected for this experiment. The flow in a manual bolus was also studied with and without the presence of an epidural catheter filter. A generalized estimating equation analysis was done to compare data between the groups. Regardless of the syringe size, there was a several-fold increase in flow when a manual bolus was used compared to a pump-administered dose, with the highest difference in the peak flow rate observed in 3-mL boluses with up to a 12-fold difference, while the difference was, at most, 7-fold in 5-mL and 10-mL boluses. Manual boluses without a filter achieve a mean peak flow rate higher than manual boluses with a filter. Our study found that manual boluses produced a higher flow rate compared to the CADD-Solis epidural pump (Smiths Medical). This study also found that the placement of a particulate filter reduces the flow rates generated while bolusing. Bulk flow rate is directly correlated with induced pressure and solution spread. Because higher bolus pressure has been shown to provide a more efficient distribution of local anesthetic and more efficient pain relief, these results may have impactful clinical significance and will pave the way for future studies.

A Prospective Observational Comparison of Two Approaches to Anesthetizing the Trachea for Awake Intubation.

Background: Multiple techniques have been described for anesthetizing the lower glottis and trachea prior to awake fiberoptic intubation. The primary aim of this study is to evaluate whether direct application of local anesthetic to the lower airway via an epidural catheter under direct vision is equally efficacious when compared to use of a transtracheal block in adult patients with an anticipated difficult airway.Methods: Patients age >18 years requiring awake fiberoptic intubation who underwent upper and lower airway topicalization were observed prospectively. Following topicalization of the upper airway, patients underwent either a transtracheal block or had their trachea and lower glottis anesthetized under direct vision via dispersion of local anesthetic through a multi-orifice epidural catheter. Choice of technique was at the discretion of the attending anesthesiologist. The primary outcome was defined as the degree of coughing observed at the time of intubation based on a 4-point ordinal scale.Results: Awake intubations in 88 patients were observed with 44 patients undergoing transtracheal block and 44 patients undergoing the epidural catheter technique. Degree of coughing with intubation was similar for each approach with a coughing score of (0, IQR (0,1)) versus (0, IQR (0,1)) in the epidural catheter and transtracheal groups respectively (p = 0.385). Duration of procedure was less in the transtracheal group (1.35 ± 1.54 min) vs. epidural catheter approach (2.86 ± 2.20 min) (p< 0.001).Conclusion: The epidural catheter and transtracheal approach appear to be equally effective at preventing coughing with intubation during awake fiberoptic intubation.

Accidental dural puncture-perioperative management.

Accidental dural puncture-perioperative management.

An in vitro evaluation of the pressure generated during programmed intermittent epidural bolus injection at varying infusion delivery speeds

Study objectiveProgrammed intermittent bolus injection of epidural anesthetic solution results in decreased anesthetic consumption and better patient satisfaction compared with continuous infusion, presumably by better spread of the anesthetic solution in the epidural space. It is not known whether the delivery speed of the bolus injection influences analgesia outcomes. The objective of this in vitro study was to determine the pressure generated by a programmed intermittent bolus pump at 4 infusion delivery speeds through open-ended, single-orifice and closed-end, multiorifice epidural catheters. DesignIn vitro observational study. SettingNot applicable. PatientsNot applicable. InterventionsA CADD-Solis Pain Management System v3.0 with Programmed Intermittent Bolus Model 2110 was connected via a 3-way adapter to an epidural catheter and a digital pressure transducer. Pressures generated by delivery speeds of 100, 175, 300, and 400 mL/h of saline solution were tested with 4 epidural catheters (2 single orifice and 2 multiorifice). These runs were replicated on 5 pumps. Analysis of variance was used to compare the mean peak pressures of each delivery speed within each catheter group (single orifice and multiorifice). Main resultsThirty runs at each delivery speed were performed with each type of catheter for a total of 240 experimental runs. Peak pressure increased with increasing delivery speeds in both catheter groups (P<.001). Peak pressures were higher with the multiorifice catheter compared with the single-orifice catheter at all delivery speeds (P<.001, for all). ConclusionUsing a pump designed for programmed intermittent infusion boluses, the delivery speed of saline solution through epidural catheters was directly related to the peak pressures. Future work should evaluate whether differences in the delivery speed of anesthetic solution into the epidural space correlate with differences in the duration and quality of analgesia during programmed intermittent epidural bolus delivery.

The analgesic efficacy of continuous transversus abdominis plane block in renal transplant recipients.

Background and Aims:Transversus abdominis plane (TAP) block is suitable for operations where parietal pain is a major cause of pain. Renal transplant recipients are ideally suited to gain maximum benefit from TAP block as the incision classically involves the lower abdomen. This study was conducted to evaluate the analgesic efficacy of continuous TAP block in transplant recipients.Material and Methods:In a prospective double-blind study, 40 chronic renal failure patients undergoing open renal transplant were randomly divided into two groups. At the end of surgery during closure, a multiorifice epidural catheter was placed in TAP plane. Study group (Group S) received Inj bupivacaine bolus 1 mg/kg (0.25%) followed by infusion 0.25 mg/kg (0.125%) through the catheter, whereas control group (Group C) received normal saline through the catheter. Inj pentazocine (0.3 mg/kg) was given as rescue analgesic at visual analogue score (VAS) > 3 in any group at rest or on movement. The analgesic efficacy was judged by VAS, time of first rescue analgesic, and total analgesic consumption in 24 h.Results:Patients in Group S had significant lower VAS scores, longer time to first rescue analgesic (270 ± 347.96 vs. 42.85 ± 32.27 min) and lower pentazocine consumption (9.75 ± 13.95 vs. 56.42 ± 12.46 mg) in 24 h. There was significant sedation in Group C.Conclusion:The TAP catheter technique for postoperative pain control after renal transplant has proved to be effective in relieving the postoperative pain after renal transplant with less pentazocine requirement and less sedation.

Continuous Lesser Palatine Nerve Block for Postoperative Analgesia After Uvulopalatopharyngoplasty

Uvulopalatopharyngoplasty (UPPP) is a commonly performed surgical intervention used to treat obstructive sleep apnea (OSA) syndrome. Continuous peripheral nerve blocks have been shown to reduce postoperative pain and opioid requirements for other surgical procedures but have not been described previously for palate surgery. We present the use of a continuous lesser palatine nerve block catheter as a part of the multimodal postoperative pain management for UPPP. Three patients were scheduled to undergo elective UPPP and tonsillectomy for OSA with scheduled postoperative hospital admission. Each patient gave written consent to share the details of his or her case. Upon completion of the surgical procedure, but before emergence from general anesthesia, a 20-G multiorifice epidural catheter was inserted into the left nasal passage, passed into the oropharynx, and either tunneled posteriorly within the anterior portion of the soft palate with the aid of a 16-G angiocatheter or placed submucosally within the soft palate by the surgeon. Each catheter was secured using clear adhesive dressings along the cheek and anchored to the ipsilateral shoulder. A continuous infusion of ropivacaine 0.2% at 2 mL/h was delivered using a disposable infusion device postoperatively, in addition to the prescribed oral and intravenous opioids. No immediate or long-term complications due to catheter placement were identified during the patient follow-up. Continuous lesser palatine nerve block may be a useful regional anesthetic technique in the multimodal postoperative pain management of opioid-sensitive OSA patients undergoing UPPP and deserves further study.

A prospective study of correlation between multi-orifice epidural catheter deviation and unilateral block in postcesarean analgesia

A prospective study of correlation between multi-orifice epidural catheter deviation and unilateral block in postcesarean analgesia

Apnea and unconsciousness after accidental subdural placement of an epidural catheter

Apnea and unconsciousness after accidental subdural placement of an epidural catheter

Transesophageal Echocardiography

Transesophageal Echocardiography

Transversus abdominis plane (TAP) catheters inserted under direct vision in the donor site following free DIEP and MS-TRAM breast reconstruction: A prospective cohort study of 45 patients

The transversus abdominis plane (TAP) block is a peripheral nerve block of T6-L1 intercostal nerves of the abdominal wall. The purpose of this study was to evaluate the usefulness of intermittent TAP blockade for the first two postoperative days following free muscle sparing-transverse rectus abdominis muscle (MS-TRAM) or deep inferior epigastric perforator (DIEP) flap reconstruction of the breast. Therapeutic--Level II evidence. This prospective cohort consisted of 45 consecutive patients who underwent DIEP or MS-TRAM free-flap breast reconstruction. Intra-operatively, a multi-orifice epidural catheter was inserted under direct vision into the TAP. Ten millilitres of 0.25% bupivacaine was injected into each TAP catheter every 12 h until removal on day 3. The control group consisted of 80 consecutive patients who underwent free MS-TRAM or DIEP free-flap breast reconstructions by the same two surgeons without TAP block. Postoperatively, both groups had patient-controlled analgesia (PCA) and the primary outcome was intravenous (IV) PCA opioid consumption in the first 48 h. There were no complications associated with using TAP catheters. The 48-h PCA-delivered opioid requirement was significantly less (p<0.001) in the TAP block group (17.10±17.23 mg IV morphine equivalent) compared to the control group (48.44±39.53 mg). Intermittent delivery of bupivacaine through the TAP block significantly reduced postoperative parenteral opioid requirements following free MS-TRAM or DIEP flap reconstruction of the breast. This is the first report of the TAP block being inserted under direct vision to provide postoperative analgesia at the abdominal flap donor site following microsurgical breast reconstruction.

In Reply

References 2–6 of our colleagues' letter all involved epidural infusion,1–5with references 2–4 suggesting analgesia is improved using repeated bolus doses compared with a simple basal infusion. But all subjects had multi-orifice epidural catheters.1–3References 5 and 6 suggest that with the same infusion method, multi-orifice epidural catheters improve analgesia compared with single-orifice designs. But all had the same local anesthetic administration technique.4,5In other words, whereas for epidural infusions repeated boluses appear to improve analgesia compared with a simple basal infusion, all of these studies involved only multi-port catheters, and thus it remains unknown if using a single-orifice catheter would have resulted in different findings (the authors of those reports did not purport such a theory).1–3Therefore, we do not believe the data supports our colleagues' statement that a “better differential sensory-motor block” is “thought to be enhanced by multi-orifice flow.”However, even if our colleagues' speculation was correct for epidural infusion, local anesthetic pharmacodynamics varies considerably among various introduction modalities. For example, local anesthetic dose, as opposed to volume or concentration, appears to be the primary determinant of block effects during continuous femoral and posterior lumbar plexus nerve blocks.6,7In contrast, the effects are mixed for epidural local anesthetic infusions: total dose is the primary determinant of analgesia quality and dermatomal spread, whereas concentration is the primary determinant of motor block and sympathectomy/hypotension.8It is for this very reason that we undertook our investigation: data from the literature involving central nervous system infusions (unfortunately) cannot be directly applied to those of the peripheral nervous system, such as the continuous femoral nerve blocks (cFNB) of our study.9We therefore do not believe that the references cited in our colleagues' letter, or any published data, supports their supposition that for continuous peripheral nerve blocks “a multi-orifice catheter is required” to “maximize” benefits.Regarding continuous peripheral nerve blocks, there are two investigations involving popliteal-sciatic local anesthetic administration suggesting that repeated boluses improve analgesia compared with a basal infusion (our colleagues cited one of these two).10,11However, both of these studies involved single-orifice perineural catheters. Therefore, there are actually more investigations suggesting the superiority of repeated boluses that used single-orifice perineural catheters than there are studies (just one involving interscalene catheters) using a multiple-orifice design.12It appears that the references cited by our colleagues contradict their theory regarding the importance of multi-orifice catheters on bolus-versus -basal administration effects.10–12Regardless, dramatic pharmacodynamic differences exist even among various continuous peripheral nerve block catheter anatomic locations, and thus the results for popliteal-sciatic and interscalene catheters are not automatically applicable to cFNB.13Our colleagues' speculation that the results of our study might be different with a multi-orifice catheter may prove accurate in the future. However, given (1) our investigation's randomized, triple-masked, split-body study design using extremely precise sensory and motor outcome measures with established reliability and validity; (2) the lack of data suggesting that the number of catheter orifice(s) impact the success of bolus-versus -basal local anesthetic administration for the peripheral (or central) nervous system; and, (3) the dramatic, often opposite, differences in pharmacodynamics among various continuous peripheral nerve block catheter anatomic locations, we believe that our concluding statement is both accurate and warranted: “this study did not find evidence to support the hypothesis that varying the method of local anesthetic administration–basal infusion versus repeated bolus doses–influences cFNB effects to a clinically significant degree. Thus, it is doubtful that, when using a cFNB, varying the method of local anesthetic administration will provide an increased sensory-to-motor block ratio and minimize motor block and the risk of falling while optimizing cutaneous analgesia.”9

An observational cohort study of the meniscus test to detect intravascular epidural catheters in pregnant women

Background The meniscus test is a rapid non-pharmacologic method of confirming epidural catheter placement by observing a normal saline meniscus while physically manipulating the catheter. The aim of this study was to assess whether the meniscus test improves diagnostic accuracy of aspiration to detect intravascular or intrathecal placement of epidural catheters in pregnant women. Methods In this prospective observational study, parturients at ⩾36 weeks of gestation were recruited. In the sitting position, participants received a multiorifice epidural catheter for elective cesarean delivery or labor analgesia. After aspiration was confirmed to be negative for blood and cerebrospinal fluid, the meniscus test was performed. Subsequently, a pharmacologic test dose was given with 1.5% lidocaine 3 mL and epinephrine 15 μg. Intravascular placement was diagnosed if the patient experienced an increase in heart rate ⩾20 beats/min within 2 min with or without tinnitus, metallic taste, dizziness, palpitations, headache, or anxiety. Results The overall intravascular catheter rate was 5.7% (24/419). The rate of intravascular catheter location not detected by aspiration was 0.95% (4/419). Given negative catheter aspiration, the meniscus test demonstrated 25% sensitivity, 87.5% specificity, and 1.9% positive predictive value for intravascular catheter insertion. No intrathecal catheters were observed. Conclusions For obstetric patients in the sitting position, the meniscus test does not improve diagnostic accuracy of aspiration for detecting intravascular multiorifice epidural catheter placement.

Case series: Combined spinal epidural anesthesia for Cesarean delivery andex utero intrapartum treatment procedure

To report the use of regional anesthesia and iv nitroglycerin to provide anesthesia and uterine relaxation for three Cesarean deliveries (CD) involving ex utero intrapartum treatment (EXIT) of potentially life-threatening airway obstruction in the newborn. Case 1--a 36-yr-old woman at 38 weeks' gestation was scheduled for an elective CD for fetal skeletal dysplasia and micrognathia. Case 2--a 34-yr-old woman at 35 weeks gestation had a fetal ultrasound revealing fixed neck flexion and micrognathia consistent with fetal arthrogryposis. Case 3--a 27-yr-old woman presented at 38 weeks gestation for CD for severe fetal micrognathia, with mandibular growth below the fifth percentile. For each case, a combined spinal epidural anesthetic was performed with 0.75% bupivacaine, fentanyl and morphine intrathecally followed by placement of a multiorifice epidural catheter. Prior to uterine incision patients received a loading dose followed by an iv infusion of nitroglycerin. Uterine relaxation was sufficient in all cases for delivery of the fetus, and allowed for evaluation by direct laryngoscopy and intubation while maintaining fetal-placental circulation. The surgical procedures were completed without incident. Anesthesia and uterine relaxation for CD and EXIT procedures can be safely provided with regional anesthesia and iv nitroglycerin.

An Alternative to Transtracheal Injection for Fiberoptic Intubation in Awake Patients: A Novel Noninvasive Technique Using a Standard Multiorifice Epidural Catheter through the Bronchoscope Suction Port

An Alternative to Transtracheal Injection for Fiberoptic Intubation in Awake Patients: A Novel Noninvasive Technique Using a Standard Multiorifice Epidural Catheter through the Bronchoscope Suction Port

Saline through the epidural needle: what volume?

To the Editor: I read with interest the article by Gadalla et al.1 However, it seems to me that the same effect can be accomplished with a smaller volume of saline administered through the epidural needle. In the author’s practice the loss of resistance to saline (LORS; 1.5–2 mL) is used for the identification of the epidural space with an 18-gauge Tuohy-Schliff epidural needle. A 27-gauge Pencan needle is inserted inside the epidural needle, 5 μg of fentanyl combined with 2.5 mg of levobupivacaine is injected intrathecally, the spinal needle is withdrawn, and 2 to 2.5 mL of normal saline is injected through the epidural needle. A 20-gauge multi-orifice epidural catheter is then inserted into the epidural space. Using this technique I have had an incidence of intravascular cannulation by the epidural catheter of 4% (unpublished data). This may be explained by the fact that with the LORS technique as opposed to the loss of resistance to air technique (LORA) some fluid is injected in the epidural space at the time of the epidural space identification. However, and importantly to the contrary, Rolbin et al. noted that there was no advantage to the injection of 3 mL of fluid into the epidural space before insertion of an epidural catheter.2 In conclusion I would challenge the authors to study several groups of patients receiving different volumes of normal saline (for example 2.5, 5, 10 mL) and use both LORS and LORA techniques for identification of the epidural space.

Multicompartment block in a parturient undergoing urgent Caesarean section

Multicompartment block in a parturient undergoing urgent Caesarean section

Quality of analgesia when air versus saline is used for identification of the epidural space in the parturient

Background and Objectives: Identification of the epidural space is often performed using the loss-of-resistance technique (LOR), commonly with air or saline. The effect of air or saline on the quality of labor epidural analgesia has not been adequately studied. Methods: Women who requested labor epidural analgesia were randomly assigned to 1 of 2 groups depending on the syringe contents used for the LOR technique and injected into the epidural space. In the air group (n = 80) the anesthesiologist used 2 mL of air, and in the saline group (n = 80) the anesthesiologist used 2 mL of 0.9% saline. After LOR was obtained, a multiorifice epidural catheter was threaded 5 cm into the epidural space and 13 mL of bupivacaine 0.25% was administered in divided doses. The success of the epidural block was determined by asking the patient if she required additional medication 15 minutes later. The occurrence of paresthesias and intravascular or subarachnoid catheters was noted. Results: In the air group, 36% of patients requested additional pain medication, and in the saline group 19% requested additional medication (P = .022). We were not able to find a statistically significant difference between groups in the incidence of paresthesias (42% air v 51% saline), intravascular catheters (5% air v 8% saline), or subarachnoid catheters (0 in both groups). Conclusions: Using 0.9% saline for the LOR technique is associated with better analgesia as compared with air for labor analgesia, and this advantage should be considered when selecting the syringe contents for the LOR technique. Reg Anesth Pain Med 2000;25:596-599.

Does the Air Test Reliably Detect Intravenous Placement of Multiorifice Epidural Catheters?

Because most studies of epidural test dose effectiveness have evaluated single-orifice catheters, Leighton et al. set out to determine the sensitivity and specificity of the air test to reliably detect intravascular placement with the currently used three-hole catheters. In 300 laboring women who requested epidural analgesia, blunt-tip, three-hole 20-gauge epidural catheters were placed at the L2–L3 or L3–L4 interspace. If neither blood nor cerebrospinal fluid (CSF) could be aspirated through the needle, 3 ml lidocaine, 2%, or 0.25% bupivacaine was injected. After a 3-min interval, patients were questioned about changes in lower extremity sensation or motor strength. If these signs of spinal anesthesia were absent, the team performed the air test by injecting 1 ml air through the epidural catheter and listening for maternal heart sound changes 15 s after injecting the air. Tests were repeated if the women experienced contractions during the observation period. If no blood was aspirated and no heart tone changes were heard, the team injected 10 ml bupivacaine, 0.125%, with 50 μg fentanyl. Epidural analgesia was continued if a sensory band was present 20 min after epidural injection.Catheters through which blood was initially aspirated were air-tested and then replaced. Patients whohadair-test-positivebutblood-aspiration-negative catheters received 100 mg lidocaine through the catheter and then were questioned about toxicity symptoms (perioral numbness, tinnitus, and diplopia).The air test detected 82% of intravascular catheters, whereas aspiration detected 91%; neither test detected all cases of intravascular placement. Eight of 11 intravascular catheters were positive for both the air test and the blood aspiration. In one air-test-positive catheter, blood could not be aspirated, and the patient developed perioral numbness after lidocaine injection. In the remaining 288 catheters, bupivacaine–fentanyl injection produced epidural analgesia in 279 patients, but no effect in another 9. The difficulty of testing multiport catheters underscores the need for careful local anesthetic dose fractionation to reduce the risk of large doses in patients with unrecognized epidurovascular or epidurointrathecal catheters.

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. 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.

The Epidural Test Dose in Obstetric Patients

The Epidural Test Dose in Obstetric Patients