Utility of Doppler in Ultrasound While Redressing a Failed Thoracic Epidural Catheter: A Case Report
Yash Shah, MD, Jasper Yeh, BA, Eric Ly, MD, Mark Kendall, MD, Vendhan Ramanujam, MD
Department of Anesthesiology, The Warren Alpert Medical School of Brown University, Providence, Rhode Island
Introduction
Thoracic epidural placement is an established technique for pain management after injury or surgery of the thorax or abdomen.
False placement of an epidural catheter is possible due to false positive loss of resistance [1].
Confirmation of a correctly placed and working epidural is usually accomplished by testing loss of dermatomal sensory levels, but this requires patient compliance with a reliable exam.
Ultrasound with Doppler flow is a quick, cost-effective bedside tool to confirm appropriate epidural placement.
Case Report
This case report is exempt from IRB review requirements as per Brown University Health policy as it is devoid of patient-identifiable information. Informed consent was obtained from the patient for submission.
A 58-year-old male with a medical history of small cell carcinoma of the right upper lung complicated by metastases to the brain and liver was admitted to the ICU following a mechanical fall, resulting in fractures to the left 8-11 ribs, left pneumohemothorax requiring chest tube decompression, and moderate pericardial and right pleural effusions.
Acute pain service placed a thoracic epidural catheter for rib-fracture-related pain management at the T8-T9 level with the loss of resistance technique.
On hospital day 2, the patient endorsed worsening pain with no definitive sensory level, so the catheter was replaced at T9-10, achieving moderate pain relief.
On hospital day 3, the patient again endorsed worsening pain with an unreliable sensory exam. Point-of-care ultrasound with Doppler flow was performed, which revealed that the epidural catheter was mispositioned out of the epidural space in a transverse ultrasound view.
Doppler flow in this view confirmed the tip of the catheter outside the lamina by viewing the spread of normal saline injectate (Figures 1 and 2).
The catheter was again replaced at T9-10, and adequate sensory levels were achieved for the next 7 days until discontinuation.
The patient passed away on hospital day 23 after developing worsening cardiac instability and hypoxic respiratory failure secondary to malignant effusions.
Thoracic epidural catheter placement following rib fractures provides superior analgesia, fewer respiratory complications, earlier mobilization, reduced opioid consumption, and decreased hospital length of stay [3].
Erroneous placement from challenges such as difficult anatomy and false perception while identifying the epidural space can lead to poor rehabilitation in these patients.
An unreliable subjective assessment of sensory distribution necessitates further objective evaluation.
Using Doppler flow in ultrasound to visualize catheter location via concomitant saline injection has demonstrated utility in confirming correct epidural placement for labor analgesia and pelvic surgery [4,5].
We successfully replicated its utility in this case. Doppler can be useful for detecting the spread of the injectate, particularly when the position of the catheter tip cannot be determined during scanning, in both transverse and longitudinal views.
Future studies focusing on Doppler ultrasound in thoracic epidural placement and position confirmation will help enhance our knowledge of its utility.
Figure 1. Ultrasound with Doppler flow showing spread of saline injectate outside lamina
Figure 2. Ultrasound image showing misplaced epidural catheter.
References
1.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. British Journal of Anaesthesia. 2006 Aug;97(2):200–7.
2.Bruins AA, Kistemaker KRJ, Boom A, Klaessens JHGM, Verdaasdonk RM, Boer C. Thermographic skin temperature measurement compared with cold sensation in predicting the efficacy and distribution of epidural anesthesia. J Clin Monit Comput. 2018 Apr;32(2):335–41.
3.Freise H, Van Aken HK. Risks and benefits of thoracic epidural anaesthesia. British Journal of Anaesthesia. 2011 Dec;107(6):859–68.
4.Elsharkawy H, Sonny A, Govindarajan SR, Chan V. Use of colour Doppler and M-mode ultrasonography to confirm the location of an epidural catheter - a retrospective case series. Can J Anesth. 2017 May;64(5):489–96.
5.Mahmoud AM, Ragab SG, Mohamed Agamy T, Shaban Goda A. The Power of Color Flow Doppler Ultrasonography Versus Blind Technique in Localization of Epidural Catheter: A Randomized Prospective Study. Anesthesiol Pain Med. 2024 Jun 30;14(3):e147828.
