Efficacy of Ultrasound-Guided Intrathecal Pump Refills Compared to Standard Palpation Technique
Ramesh M. Singa MD, MHS; Mario Moric MS; Asokumar Buvanendran MD
Department of Anesthesiology, Rush University Medical Center, Chicago, IL
Improper intrathecal pump (ITP) refill can be associated with a high risk of morbidity and mortality. Many cases have occurred following inadvertent side port access or incomplete reservoir port access. Nevertheless, the standard method of refilling an ITP involves palpated needle guidance. Recently, the 2017 Polyanalgesic Consensus Conference recommendations describe ultrasound guidance for pump refill when the port is difficult to identify. The purpose of this study was to assess whether ultrasound guidance for ITP refills conveys clinical advantages to support use on a regular basis for ITP refills.
The study was approved by the Rush University Medical Center institutional review board. Informed written consent was obtained from all participants. Patients requiring an ITP refill between 1 August 2016 and 30 June 2017 were recruited. Participants had their ITP refilled using ultrasound guidance initially after enrollment; subsequent refills alternated with manual palpation and ultrasound guidance. The time to reservoir port access, the number of needle maneuvers/punctures, procedural pain on (NRS 0-10), complications, and patient satisfaction/refill preference and post-procedural pain were recorded. Data was compared between ultrasound and palpation guidance using the Mann-Whitney U test or Pearson’s chi-square.
A total of 107 patients underwent 192 refills, median (range) 1(1-10) refill procedures. There were 67 palpated refills and 125 using ultrasound guidance. No procedural pain (NRS=0) was reported in 84% the ultrasound guided compared with 67% of the palpation procedures, difference -17%, (95% difference -3% to -31%, P=0.01). Median (IQR) procedure duration was 60 (49 to 82) sec and 90 (75 to 99) seconds for the palpated and ultrasound guided procedures, respectively (P<0.001). There was no difference between the groups in needle punctures (P=0.87) or redirections (P=0.34). There were no complications such as pocket fill or intrathecal bolus with either refill technique. There was no difference in post-procedure patient satisfaction. Following 35(52%) of the palpated procedures, patients stated they would have preferred ultrasound guidance, but only after 12 of the ultrasound guided procedures did patients suggest they would prefer palpated guidance (P<0.001).
The important finding of this study was that ultrasound-guided ITP refills had greater patient preference and less patients report procedural pain. Conversely, the palpation technique required less time to secure reservoir port access. However, reservoir port access time is substantially less than the refill time, so the overall duration of the refill is not clinically prolonged. There were no adverse events with either technique so we cannot assess comparative safety of the methods. Nevertheless, given the inherent benefits of using ultrasound for visualization and its positive impact on procedures such as central venous catheterization, its implementation for regularly scheduled refills seems appropriate.
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