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Clinical application of a novel developed pressure bladder indicator in lumbar epidural puncture
Journal of Clinical Anesthesia (2015) 27, 543–547
Original Contribution
Clinical application of a novel developed pressure bladder indicator in lumbar epidural puncture Xiaofeng Liu MM a,b,1 , E-er-dun Wang MM b,1 , Qing Yan BS b , Kezhong Li MD a,c,⁎ a
Department of Anesthesiology, The Second Hospital of Shandong University, Jinan 250033, China Department of Anesthesiology, No. 401 Hospital of PLA, Qingdao 266071, China c Department of Anesthesiology, Yantai Yuhuangding Hospital, Yantai 264000, China b
Received 15 October 2014; revised 3 February 2015; accepted 13 July 2015
Keywords: Epidural space; Pressure; Lumbar epidural puncture; Pressure bladder indicator
Abstract Study Objective: A novel pressure bladder indicator was developed, and this study aimed to evaluate the clinical application of the pressure bladder indicator by measuring the epidural space pressure and bladder working pressure on patients undergoing lumbar epidural puncture. Design: Randomized, prospective, double-blinded study Patients: 130 patients Setting: The Second Hospital of Shandong University Interventions: In this study, 60 patients undergoing surgical procedures under lumbar epidural anesthesia were enrolled to detect epidural pressure, and other 70 patients who were undergoing lumbar epidural anesthesia or combined spinal-epidural anesthesia were enrolled to evaluate the pressure bladder indicator. Measurements: After successful breakthrough of ligamentum flavum by traditional methods, a pressure transducer was connected to an epidural needle tail and a monitor to measure the epidural pressure at L1-L5 in 60 patients. The working pressure of the bladder was also measured by a transducer. Then lumbar epidural puncture was performed with the pressure bladder indicator in other 70 patients. Main Results: The lumbar epidural pressure of the 60 patients was 9.8 ± 4.3 mm Hg, and the bladder working pressure of the pressure bladder indicator was 122 ± 15 mm Hg. All these 70 patients were confirmed with successful bladder indication and lumbar epidural puncture. Thus, the coincidence ratio was 100%. Conclusions: The novel developed pressure bladder indicator was a reliable and useful technique to conduct successful lumbar epidural puncture. © 2015 Elsevier Inc. All rights reserved.
1. Introduction Epidural anesthesia is a commonly used technique during obstetric operation [1]; nevertheless, it was also one of the ⁎ Corresponding author at: Department of Anesthesiology, Yantai Yuhuangding Hospital, No. 20 Yudong Road, Zhifu Dstrict, Yantai 264000, China. Tel./fax: + 86 535 66919999 81427. E-mail address: [email protected] (K. Li). 1 Co-first authors. http://dx.doi.org/10.1016/j.jclinane.2015.07.017 0952-8180/© 2015 Elsevier Inc. All rights reserved.
most difficult procedures to perform in anesthesiology [2]. One retrospective study evaluated epidural anesthesia in laboring women and found a failure rate of 14% [3]. Hermanides et al [4] also investigated a number of studies on epidural anesthesia, not just in childbirth, and concluded that the overall failure rate was around 30%. Among the failed epidurals, incorrect catheter placement related to identification of epidural space was responsible for half of the failures [5]. Postdural puncture headache has been recognized a
544 common complication due to epidural placement in the obstetric population [6]. Currently, the most common method used for epidural space identification is sudden loss-of-resistance (LOR) when the tip of the needle passes the ligamentum flavum [7]. However, these traditional methods are overdependent on experiences and skills of anesthetists [8]. Therefore, it is extremely important to develop an alternative and objective method to ensure correct identification of the epidural space. Despite many advancements in medicine and technology such as electrical stimulation [9], ultrasonography [10,11], and computed tomography [12], these techniques are limited to clinical application due to additional and expensive equipment. Our department have developed a pressure bladder indicator with a bladder fixed on the sidewall of a regular syringe, which can be filled with liquid and maintain pressure. The feasibility of pressure bladder indicator has been preliminary proved in helping T3-L3 pressure demonstrated in our previous study [13]. Hence, this study aimed to further and specially evaluate the clinical application of the pressure bladder indicator by measuring the epidural space pressure and bladder working pressure on patients undergoing lumbar epidural puncture.
2. Materials and methods 2.1. Patients This study was approved by the Medical Ethics Committee of our hospital, and all patients or their families signed informed consent forms. In this study, 60 patients undergoing surgical procedures under lumbar epidural anesthesia were enrolled to detect epidural pressure, and the other 70 patients who would receive lumbar epidural anesthesia or combined spinal-epidural (CSE) anesthesia were enrolled to evaluate the pressure bladder indicator. Both groups of the patients were at the age range from 18 to 60 years, with body mass index between 20 and 30 kg/m2. Patients who had contraindications of lumbar epidural anesthesia or abnormality in cardiopulmonary function were all excluded.
X. Liu et al. feeling on ligamenta flavum, LOR technique with saline, and hanging drop techniques [14]. However, local anesthetic was not injected momentarily at this time. A disposable pressure transducer (Biosensors International, Singapore) was connected to an epidural needle tail and a monitor (M8003A; Philips, Hamburg, Germany) to determine the lumbar epidural pressure, during which time the epidural needle was kept unremoved. Finally, epidural catheter was inserted and local anesthetic was injected routinely. From the obtained satisfactory anesthetic effect, it was further confirmed that the epidural needle tip was just in epidural space (Fig. 1).
2.3. Determination of bladder working pressure The pressure bladder indicator was devised based on high friction between the syringe piston and the intine, and on the principle of “deformation in the elastic device by decompression.” Its main basal structure was like a 5-mL syringe with an open pore on lateral wall at 1 cm from the anterior extremity of the syringe. The open pore was installed with a rubber membrane. The blockage of syringe tip with pulsive piston would exert increasing pressure within the syringe and make the membrane inflated outward, forming a liquid bladder at a diameter of 1.0 to 1.5 cm. During the continued puncture procedure (with hand away from piston), the adequate frictional resistance between the syringe piston and the intine could prevent the piston from drawing back, thus keeping the bladder inflated. Fifty pressure bladder indicators were randomly selected and individually drew 5 mL of physiological saline. After the pressure bladder indicator was connected to the pressure transducer, 2 mL of physiological saline was pushed out to expand the bladder, without gas leak. Then the currently displayed pressure, unchanged for 5 seconds, was recorded as the bladder's working pressure (Fig. 2).
2.2. Determination of lumbar epidural pressure The 60 patients underwent 6 hours of food deprivation and 4 hours of water deprivation before anesthesia. Then they were premedicated with penehyclidine hydrochloride (0.02 mg/kg) and midazolam (0.02-0.05 mg/kg) by intravenous injection, with no intravenous fluid infusion before lumbar epidural punctures. The operating table was in a horizontal position, and patients were placed in lateral flexed position, with rachial horizon as the standard zero. After routine disinfection, the epidural space was located usually at L1-L5 with an 18-gauge epidural needle. In all these cases, successful lumbar epidural puncture was achieved using the traditional methods, including an obvious breakthrough
Fig. 1 The lumbar epidural pressure was determined with a disposable pressure transducer connected to the epidural needle tail and a monitor.
Epidural puncture by pressure bladder indicator
545
2.4. Application of the pressure bladder indicator in lumbar epidural puncture The pressure bladder indicator drew 5 mL of physiological saline (local anesthetic or air was not recommended despite not affecting the results) and was connected to a common epidural needle. The epidural needle pierced the skin and subcutaneous loose tissue, and then reached the ligament or anadesma. Meanwhile, the piston was pushed forward for 2 mL. The membrane was then expanded due to the resistance of ligament-induced pressure within the syringe, formed a bladder, and remained engorged (Fig. 3). The forward needling was continued slowly (please note that the needle retropulsion was forbidden). At the moment when the needle reached the epidural space, the bladder automatically released physiological saline into the epidural space and was shrivelled promptly due to the low internal pressure in the space, indicating a successful lumbar epidural puncture. The remaining 70 patients would receive lumbar epidural anesthesia with the pressure bladder indicator as described above. After the bladder was shrivelled, traditional criterions including the depth of needling, a breakthrough feeling on ligamenta flavum, LOR, and bubble compression disappearance were used to confirm if the epidural needle reached the epidural space.
Fig. 3 Lumbar epidural puncture was performed with the pressure bladder indicator.
The effects of the pressure bladder indicator were evaluated as follows. (1) It would be a successful bladder indication with promptly shrivelled bladder and the needle in epidural space further confirmed by traditional criterions. Successful indication was divided into rapid indication (the bladder was shrivelled within 1 second) and delayed indication (the bladder was shrivelled beyond 1 second). (2) A false-positive indication would be confirmed as promptly shrivelled bladder but with the needle not in epidural space by traditional criterions. (3) It would be a false-negative indication if traditional criterions and a satisfactory anesthetic effect confirmed it successful but the bladder was not shrivelled. After successful bladder indication, the indicator was removed and the epidural catheter and lumbar puncture needle were inserted routinely for patients who would undergo lumbar epidural anesthesia and CSE anesthesia, respectively. Then the local anesthetic was injected and the anesthetic effect was observed. A successful puncture was confirmed as a successful insertion of epidural catheter for lumbar epidural anesthesia, outflow of cerebrospinal fluid after insertion of lumbar puncture needle for CSE anesthesia, satisfactory anesthetic effect, and successful progress of surgery. The coincidence between bladder indication confirmed by traditional means and successful lumbar epidural puncture was calculated.
3. Results
Fig. 2 Bladder working pressure was determined by a pressure transducer connected to the pressure bladder indicator with expanded bladder.
The epidural space pressure of the 60 patients was 9.8 ± 4.3 mm Hg in this study. Two patients who had blood reflow in the syringe during the process of lumbar epidural puncture and obtained unsatisfactory anesthetic effect were excluded from the study. The bladder working pressure of the pressure bladder indicator was 122 ± 15 mm Hg when 2 mL of physiological saline was pushed out.
546 All these 70 patients were confirmed with successful bladder indication and lumbar epidural puncture. Thus, the coincidence ratio was 100%. Besides, 62 patients had rapid bladder indication, whereas 8 patients had delayed bladder indication. After changing the needling direction, all 8 patients also had rapid bladder indication. No false-negative or false-positive indications occurred.
4. Discussion As failure of epidural anesthesia occurs in up to 30% clinical practices [4], epidural catheters should be placed correctly because it accounted for half of the failures [5]. Correct placement obviously requires correct identification of the epidural space. However, traditional methods used to confirm the position of epidural needle position, such as LOR, a breakthrough feeling on ligamenta flavum, and the hanging drop technique, were usually experience-based and blinded and had no evidence-based manner [14]. Hence, this study described a novel developed pressure bladder indicator, an objective indicator and tool to confirm successful lumbar epidural puncture. In this study, the result showed that the epidural space (L1-L5) had a positive pressure of 9.8 ± 4.3 mm Hg, which was similar to previous study that reported that epidural space (L2-L3 or L3-L4) was 7.69 ± 10.36 mm Hg [15]. Clinically negative pressure might only occur at the moment when the needle pierced ligamenta flava. However, there might be differences in epidural pressure at different segments of spinal column and in the populations at different ages. Gong et al [15] also reported that the pressure rapidly increased when the needle punctured through the skin to the ligamenta flava, and then declined when the needle punctured through the ligamenta flava and reached the epidural space. Besides, the working pressure of bladder should be higher than the lumbar epidural pressure. Because the low working pressure of bladder might cause the bladder not shrivelled after the epidural needle reached the epidural space (false negative indication). However, extremely high working pressure would also result in the shrivelled bladder before the needle reached the epidural space (false-positive indication). This study showed that the pressure of our bladder indicator was 122 ± 15 mm Hg, which was suitable for lumbar epidural pressure. One of the key points for successful bladder indication was that the needle must not be withdrawn once the bladder expanded. If the direction of the needle needed to be changed, the bladder should be reproduced after the adjustment of the needle direction. Otherwise, the bladder would automatically release the fluid into the soft tissue in advance (false-positive indication due to misoperation). As shown in this study, successful bladder indication and lumbar epidural puncture were observed in all 70 patients, with a coincidence ratio of 100%, indicating that the sensitivity of the bladder indicator in confirming the correct
X. Liu et al. location of the epidural needle tip is high. After successful indications of lumbar epidural puncture, all patients were placed correctly with epidural catheter, with outflow of cerebrospinal fluid and anesthesia satisfaction after injection of anesthetics, whereas a previous study has reported a high incidence of catheter misplacement in thoracic epidurals with the LOR method, especially in general anesthesia [16]. It seemed that this device was of great assistance in identifying the epidural space in patients and was at least a reliable and useful technique like a traditional method for epidural puncture because no grouping with traditional methods such as LOR technique was conducted in this study. Apart from the above clinical effects, this pressure bladder indicator also provided a visible “brake signal” indicating correctly that the needle had reached the epidural space. Hence, unlike traditional methods, this procedure was feeling and experience independent. Several limitations to this study must be addressed. First, the cases of patients enrolled in this study were insufficient, and no grouping with traditional methods was conducted. Thus, further study should be performed as above on a larger number of patients to compare the effect of this pressure bladder indicator and LOR technique. Second, there remained no available data with regard to its safety, as complications associated with lumbar epidural anesthesia were not monitored after surgery. In conclusion, the novel developed pressure bladder indicator was a reliable and useful technique to conduct successful lumbar epidural puncture.
References [1] Osterman MJ, Martin JA. Epidural and spinal anesthesia use during labor: 27-state reporting area, 2008. National vital statistics reports: from the Centers for Disease Control and Prevention, National Center for Health Statistics, National Vital Statistics System, 59; 2011 1-13[6]. [2] Mackenzie I, Xu J, Cusick C, Midwinter-Morten H, Meacher H, Mollison J, et al. Acupuncture for pain relief during induced labor in nulliparae: a randomized controlled study. Obstet Anesth Dig 2012;32:52-3. [3] Pan P, Bogard T, Owen M. Incidence and characteristics of failures in obstetric neuraxial analgesia and anesthesia: a retrospective analysis of 19,259 deliveries. Int J Obstet Anesth 2004;13:227-33. [4] Hermanides J, Hollmann M, Stevens M, Lirk P. Failed epidural: causes and management. Br J Anaesth 2012;109:144-54. [5] Motamed C, Farhat F, Rémérand F, Stéphanazzi J, Laplanche A, Jayr C. An analysis of postoperative epidural analgesia failure by computed tomography epidurography. Anesth Analg 2006;103:1026-32. [6] Choi PT, Galinski SE, Takeuchi L, Lucas S, Tamayo C, Jadad AR. PDPH is a common complication of neuraxial blockade in parturients: a meta-analysis of obstetrical studies. Can J Anesth 2003;50:460-9. [7] Tielens LK, Bruhn J, Vogt M, van Geffen GJ, Scheffer GJ. The Episure Autodetect syringe, a loss-of-resistance technique for locating the epidural space, used in pediatric patients. Paediatr Anaesth 2013;23:747-50. [8] Levin J, Wetzel R, Smuck M. The importance of image guidance during epidural injections: rates of incorrect needle placement during non-image guided epidural injections. J Spine 2012;1:1-3. [9] Otero PE, Portela DA, Brinkyer JA, Tarragona L, Zaccagnini AS, Fuensalida SE, et al. Use of electrical stimulation to monitor lumbosacral epidural and intrathecal needle placement in rabbits. Am J Vet Res 2012; 73:1137-41.
Epidural puncture by pressure bladder indicator [10] Roberts SA, Galvez I. Ultrasound assessment of caudal catheter position in infants. Pediatr Anesth 2005;15:429-32. [11] Willschke H, Marhofer P, Bösenberg A, Johnston S, Wanzel O, Sitzwohl C, et al. Epidural catheter placement in children: comparing a novel approach using ultrasound guidance and a standard loss-of-resistance technique. Br J Anaesth 2006;97: 200-7. [12] Murata H, Sakai T, Goto S, Sumikawa K. Three-dimensional computed tomography for difficult thoracic epidural needle placement. Anesth Analg 2008;106:654-8. [13] Yan Q, Liu X-f, Liu W, Wang E-e-d, Wang Yan-wen, Xiancheng Qiang, Wei-bin Pang. Efficacy of pressure bladder
547 indicator in guiding epidural puncture. Chin J Anesthesiol 2010;30:582-4. [14] Wantman A, Hancox N, Howell P. Techniques for identifying the epidural space: a survey of practice amongst anaesthetists in the UK. Anaesthesia 2006;61:370-5. [15] Gong Y, Shi H, Wu J, Labu D, Sun J, Zhong H, et al. Pressure waveform-guided epidural catheter placement in comparison to the loss-of-resistance conventional method. J Clin Anesth 2014;26: 395-401. [16] Lin T-C, Huang Y-S, Lee S-C, Ho S-T, Cherng C-H, Lu C-C. Intrapleural misplacement of a thoracic epidural catheter in an anesthetized patient. Acta Anaesthesiol Taiwan 2008;46:49-52.
Original Contribution
Clinical application of a novel developed pressure bladder indicator in lumbar epidural puncture Xiaofeng Liu MM a,b,1 , E-er-dun Wang MM b,1 , Qing Yan BS b , Kezhong Li MD a,c,⁎ a
Department of Anesthesiology, The Second Hospital of Shandong University, Jinan 250033, China Department of Anesthesiology, No. 401 Hospital of PLA, Qingdao 266071, China c Department of Anesthesiology, Yantai Yuhuangding Hospital, Yantai 264000, China b
Received 15 October 2014; revised 3 February 2015; accepted 13 July 2015
Keywords: Epidural space; Pressure; Lumbar epidural puncture; Pressure bladder indicator
Abstract Study Objective: A novel pressure bladder indicator was developed, and this study aimed to evaluate the clinical application of the pressure bladder indicator by measuring the epidural space pressure and bladder working pressure on patients undergoing lumbar epidural puncture. Design: Randomized, prospective, double-blinded study Patients: 130 patients Setting: The Second Hospital of Shandong University Interventions: In this study, 60 patients undergoing surgical procedures under lumbar epidural anesthesia were enrolled to detect epidural pressure, and other 70 patients who were undergoing lumbar epidural anesthesia or combined spinal-epidural anesthesia were enrolled to evaluate the pressure bladder indicator. Measurements: After successful breakthrough of ligamentum flavum by traditional methods, a pressure transducer was connected to an epidural needle tail and a monitor to measure the epidural pressure at L1-L5 in 60 patients. The working pressure of the bladder was also measured by a transducer. Then lumbar epidural puncture was performed with the pressure bladder indicator in other 70 patients. Main Results: The lumbar epidural pressure of the 60 patients was 9.8 ± 4.3 mm Hg, and the bladder working pressure of the pressure bladder indicator was 122 ± 15 mm Hg. All these 70 patients were confirmed with successful bladder indication and lumbar epidural puncture. Thus, the coincidence ratio was 100%. Conclusions: The novel developed pressure bladder indicator was a reliable and useful technique to conduct successful lumbar epidural puncture. © 2015 Elsevier Inc. All rights reserved.
1. Introduction Epidural anesthesia is a commonly used technique during obstetric operation [1]; nevertheless, it was also one of the ⁎ Corresponding author at: Department of Anesthesiology, Yantai Yuhuangding Hospital, No. 20 Yudong Road, Zhifu Dstrict, Yantai 264000, China. Tel./fax: + 86 535 66919999 81427. E-mail address: [email protected] (K. Li). 1 Co-first authors. http://dx.doi.org/10.1016/j.jclinane.2015.07.017 0952-8180/© 2015 Elsevier Inc. All rights reserved.
most difficult procedures to perform in anesthesiology [2]. One retrospective study evaluated epidural anesthesia in laboring women and found a failure rate of 14% [3]. Hermanides et al [4] also investigated a number of studies on epidural anesthesia, not just in childbirth, and concluded that the overall failure rate was around 30%. Among the failed epidurals, incorrect catheter placement related to identification of epidural space was responsible for half of the failures [5]. Postdural puncture headache has been recognized a
544 common complication due to epidural placement in the obstetric population [6]. Currently, the most common method used for epidural space identification is sudden loss-of-resistance (LOR) when the tip of the needle passes the ligamentum flavum [7]. However, these traditional methods are overdependent on experiences and skills of anesthetists [8]. Therefore, it is extremely important to develop an alternative and objective method to ensure correct identification of the epidural space. Despite many advancements in medicine and technology such as electrical stimulation [9], ultrasonography [10,11], and computed tomography [12], these techniques are limited to clinical application due to additional and expensive equipment. Our department have developed a pressure bladder indicator with a bladder fixed on the sidewall of a regular syringe, which can be filled with liquid and maintain pressure. The feasibility of pressure bladder indicator has been preliminary proved in helping T3-L3 pressure demonstrated in our previous study [13]. Hence, this study aimed to further and specially evaluate the clinical application of the pressure bladder indicator by measuring the epidural space pressure and bladder working pressure on patients undergoing lumbar epidural puncture.
2. Materials and methods 2.1. Patients This study was approved by the Medical Ethics Committee of our hospital, and all patients or their families signed informed consent forms. In this study, 60 patients undergoing surgical procedures under lumbar epidural anesthesia were enrolled to detect epidural pressure, and the other 70 patients who would receive lumbar epidural anesthesia or combined spinal-epidural (CSE) anesthesia were enrolled to evaluate the pressure bladder indicator. Both groups of the patients were at the age range from 18 to 60 years, with body mass index between 20 and 30 kg/m2. Patients who had contraindications of lumbar epidural anesthesia or abnormality in cardiopulmonary function were all excluded.
X. Liu et al. feeling on ligamenta flavum, LOR technique with saline, and hanging drop techniques [14]. However, local anesthetic was not injected momentarily at this time. A disposable pressure transducer (Biosensors International, Singapore) was connected to an epidural needle tail and a monitor (M8003A; Philips, Hamburg, Germany) to determine the lumbar epidural pressure, during which time the epidural needle was kept unremoved. Finally, epidural catheter was inserted and local anesthetic was injected routinely. From the obtained satisfactory anesthetic effect, it was further confirmed that the epidural needle tip was just in epidural space (Fig. 1).
2.3. Determination of bladder working pressure The pressure bladder indicator was devised based on high friction between the syringe piston and the intine, and on the principle of “deformation in the elastic device by decompression.” Its main basal structure was like a 5-mL syringe with an open pore on lateral wall at 1 cm from the anterior extremity of the syringe. The open pore was installed with a rubber membrane. The blockage of syringe tip with pulsive piston would exert increasing pressure within the syringe and make the membrane inflated outward, forming a liquid bladder at a diameter of 1.0 to 1.5 cm. During the continued puncture procedure (with hand away from piston), the adequate frictional resistance between the syringe piston and the intine could prevent the piston from drawing back, thus keeping the bladder inflated. Fifty pressure bladder indicators were randomly selected and individually drew 5 mL of physiological saline. After the pressure bladder indicator was connected to the pressure transducer, 2 mL of physiological saline was pushed out to expand the bladder, without gas leak. Then the currently displayed pressure, unchanged for 5 seconds, was recorded as the bladder's working pressure (Fig. 2).
2.2. Determination of lumbar epidural pressure The 60 patients underwent 6 hours of food deprivation and 4 hours of water deprivation before anesthesia. Then they were premedicated with penehyclidine hydrochloride (0.02 mg/kg) and midazolam (0.02-0.05 mg/kg) by intravenous injection, with no intravenous fluid infusion before lumbar epidural punctures. The operating table was in a horizontal position, and patients were placed in lateral flexed position, with rachial horizon as the standard zero. After routine disinfection, the epidural space was located usually at L1-L5 with an 18-gauge epidural needle. In all these cases, successful lumbar epidural puncture was achieved using the traditional methods, including an obvious breakthrough
Fig. 1 The lumbar epidural pressure was determined with a disposable pressure transducer connected to the epidural needle tail and a monitor.
Epidural puncture by pressure bladder indicator
545
2.4. Application of the pressure bladder indicator in lumbar epidural puncture The pressure bladder indicator drew 5 mL of physiological saline (local anesthetic or air was not recommended despite not affecting the results) and was connected to a common epidural needle. The epidural needle pierced the skin and subcutaneous loose tissue, and then reached the ligament or anadesma. Meanwhile, the piston was pushed forward for 2 mL. The membrane was then expanded due to the resistance of ligament-induced pressure within the syringe, formed a bladder, and remained engorged (Fig. 3). The forward needling was continued slowly (please note that the needle retropulsion was forbidden). At the moment when the needle reached the epidural space, the bladder automatically released physiological saline into the epidural space and was shrivelled promptly due to the low internal pressure in the space, indicating a successful lumbar epidural puncture. The remaining 70 patients would receive lumbar epidural anesthesia with the pressure bladder indicator as described above. After the bladder was shrivelled, traditional criterions including the depth of needling, a breakthrough feeling on ligamenta flavum, LOR, and bubble compression disappearance were used to confirm if the epidural needle reached the epidural space.
Fig. 3 Lumbar epidural puncture was performed with the pressure bladder indicator.
The effects of the pressure bladder indicator were evaluated as follows. (1) It would be a successful bladder indication with promptly shrivelled bladder and the needle in epidural space further confirmed by traditional criterions. Successful indication was divided into rapid indication (the bladder was shrivelled within 1 second) and delayed indication (the bladder was shrivelled beyond 1 second). (2) A false-positive indication would be confirmed as promptly shrivelled bladder but with the needle not in epidural space by traditional criterions. (3) It would be a false-negative indication if traditional criterions and a satisfactory anesthetic effect confirmed it successful but the bladder was not shrivelled. After successful bladder indication, the indicator was removed and the epidural catheter and lumbar puncture needle were inserted routinely for patients who would undergo lumbar epidural anesthesia and CSE anesthesia, respectively. Then the local anesthetic was injected and the anesthetic effect was observed. A successful puncture was confirmed as a successful insertion of epidural catheter for lumbar epidural anesthesia, outflow of cerebrospinal fluid after insertion of lumbar puncture needle for CSE anesthesia, satisfactory anesthetic effect, and successful progress of surgery. The coincidence between bladder indication confirmed by traditional means and successful lumbar epidural puncture was calculated.
3. Results
Fig. 2 Bladder working pressure was determined by a pressure transducer connected to the pressure bladder indicator with expanded bladder.
The epidural space pressure of the 60 patients was 9.8 ± 4.3 mm Hg in this study. Two patients who had blood reflow in the syringe during the process of lumbar epidural puncture and obtained unsatisfactory anesthetic effect were excluded from the study. The bladder working pressure of the pressure bladder indicator was 122 ± 15 mm Hg when 2 mL of physiological saline was pushed out.
546 All these 70 patients were confirmed with successful bladder indication and lumbar epidural puncture. Thus, the coincidence ratio was 100%. Besides, 62 patients had rapid bladder indication, whereas 8 patients had delayed bladder indication. After changing the needling direction, all 8 patients also had rapid bladder indication. No false-negative or false-positive indications occurred.
4. Discussion As failure of epidural anesthesia occurs in up to 30% clinical practices [4], epidural catheters should be placed correctly because it accounted for half of the failures [5]. Correct placement obviously requires correct identification of the epidural space. However, traditional methods used to confirm the position of epidural needle position, such as LOR, a breakthrough feeling on ligamenta flavum, and the hanging drop technique, were usually experience-based and blinded and had no evidence-based manner [14]. Hence, this study described a novel developed pressure bladder indicator, an objective indicator and tool to confirm successful lumbar epidural puncture. In this study, the result showed that the epidural space (L1-L5) had a positive pressure of 9.8 ± 4.3 mm Hg, which was similar to previous study that reported that epidural space (L2-L3 or L3-L4) was 7.69 ± 10.36 mm Hg [15]. Clinically negative pressure might only occur at the moment when the needle pierced ligamenta flava. However, there might be differences in epidural pressure at different segments of spinal column and in the populations at different ages. Gong et al [15] also reported that the pressure rapidly increased when the needle punctured through the skin to the ligamenta flava, and then declined when the needle punctured through the ligamenta flava and reached the epidural space. Besides, the working pressure of bladder should be higher than the lumbar epidural pressure. Because the low working pressure of bladder might cause the bladder not shrivelled after the epidural needle reached the epidural space (false negative indication). However, extremely high working pressure would also result in the shrivelled bladder before the needle reached the epidural space (false-positive indication). This study showed that the pressure of our bladder indicator was 122 ± 15 mm Hg, which was suitable for lumbar epidural pressure. One of the key points for successful bladder indication was that the needle must not be withdrawn once the bladder expanded. If the direction of the needle needed to be changed, the bladder should be reproduced after the adjustment of the needle direction. Otherwise, the bladder would automatically release the fluid into the soft tissue in advance (false-positive indication due to misoperation). As shown in this study, successful bladder indication and lumbar epidural puncture were observed in all 70 patients, with a coincidence ratio of 100%, indicating that the sensitivity of the bladder indicator in confirming the correct
X. Liu et al. location of the epidural needle tip is high. After successful indications of lumbar epidural puncture, all patients were placed correctly with epidural catheter, with outflow of cerebrospinal fluid and anesthesia satisfaction after injection of anesthetics, whereas a previous study has reported a high incidence of catheter misplacement in thoracic epidurals with the LOR method, especially in general anesthesia [16]. It seemed that this device was of great assistance in identifying the epidural space in patients and was at least a reliable and useful technique like a traditional method for epidural puncture because no grouping with traditional methods such as LOR technique was conducted in this study. Apart from the above clinical effects, this pressure bladder indicator also provided a visible “brake signal” indicating correctly that the needle had reached the epidural space. Hence, unlike traditional methods, this procedure was feeling and experience independent. Several limitations to this study must be addressed. First, the cases of patients enrolled in this study were insufficient, and no grouping with traditional methods was conducted. Thus, further study should be performed as above on a larger number of patients to compare the effect of this pressure bladder indicator and LOR technique. Second, there remained no available data with regard to its safety, as complications associated with lumbar epidural anesthesia were not monitored after surgery. In conclusion, the novel developed pressure bladder indicator was a reliable and useful technique to conduct successful lumbar epidural puncture.
References [1] Osterman MJ, Martin JA. Epidural and spinal anesthesia use during labor: 27-state reporting area, 2008. National vital statistics reports: from the Centers for Disease Control and Prevention, National Center for Health Statistics, National Vital Statistics System, 59; 2011 1-13[6]. [2] Mackenzie I, Xu J, Cusick C, Midwinter-Morten H, Meacher H, Mollison J, et al. Acupuncture for pain relief during induced labor in nulliparae: a randomized controlled study. Obstet Anesth Dig 2012;32:52-3. [3] Pan P, Bogard T, Owen M. Incidence and characteristics of failures in obstetric neuraxial analgesia and anesthesia: a retrospective analysis of 19,259 deliveries. Int J Obstet Anesth 2004;13:227-33. [4] Hermanides J, Hollmann M, Stevens M, Lirk P. Failed epidural: causes and management. Br J Anaesth 2012;109:144-54. [5] Motamed C, Farhat F, Rémérand F, Stéphanazzi J, Laplanche A, Jayr C. An analysis of postoperative epidural analgesia failure by computed tomography epidurography. Anesth Analg 2006;103:1026-32. [6] Choi PT, Galinski SE, Takeuchi L, Lucas S, Tamayo C, Jadad AR. PDPH is a common complication of neuraxial blockade in parturients: a meta-analysis of obstetrical studies. Can J Anesth 2003;50:460-9. [7] Tielens LK, Bruhn J, Vogt M, van Geffen GJ, Scheffer GJ. The Episure Autodetect syringe, a loss-of-resistance technique for locating the epidural space, used in pediatric patients. Paediatr Anaesth 2013;23:747-50. [8] Levin J, Wetzel R, Smuck M. The importance of image guidance during epidural injections: rates of incorrect needle placement during non-image guided epidural injections. J Spine 2012;1:1-3. [9] Otero PE, Portela DA, Brinkyer JA, Tarragona L, Zaccagnini AS, Fuensalida SE, et al. Use of electrical stimulation to monitor lumbosacral epidural and intrathecal needle placement in rabbits. Am J Vet Res 2012; 73:1137-41.
Epidural puncture by pressure bladder indicator [10] Roberts SA, Galvez I. Ultrasound assessment of caudal catheter position in infants. Pediatr Anesth 2005;15:429-32. [11] Willschke H, Marhofer P, Bösenberg A, Johnston S, Wanzel O, Sitzwohl C, et al. Epidural catheter placement in children: comparing a novel approach using ultrasound guidance and a standard loss-of-resistance technique. Br J Anaesth 2006;97: 200-7. [12] Murata H, Sakai T, Goto S, Sumikawa K. Three-dimensional computed tomography for difficult thoracic epidural needle placement. Anesth Analg 2008;106:654-8. [13] Yan Q, Liu X-f, Liu W, Wang E-e-d, Wang Yan-wen, Xiancheng Qiang, Wei-bin Pang. Efficacy of pressure bladder
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