Insertion of an Intrathecal Catheter Following a Recognised Accidental Dural Puncture Reduces the Need for an Epidural Blood Patch in Parturients: an Australian Retrospective Study

Rana K, Jenkins S and Rana M.

International Journal of Obstetric Anesthesia 2018; 36: 11–16

Aim of Study

To investigate whether insertion of an intrathecal catheter (ITC) following accidental dural puncture (ADP) reduces the incidence of post dural puncture headache (PDPH) and need for epidural blood patch (EBP)

Design and Location

Retrospective

Lyell McEwin Hospital, South Australia – (Tertiary centre)

Methodology

• Used their acute pain database to identify patients
  • All patients who had a PDPH and/ or ADP between Jan 2009 – Dec 2015
  • Whether ITC was inserted and if so for how long (>= 24h or < 24h)
  • presence of PDPH
  • need for EBP and for repeat EBP
• PDPH diagnosis made by acute pain team (overseen by consultant anaesthetist)
• Initial management was conservative, but when this didn’t work EBP was discussed
• 18G Tuohy needle used for all epidurals
• Analgesic boluses via ITC were 0.2% ropivicaine and topped up with 0.5% bupivicaine for Caesarean section

Primary Outcome

To investigate whether insertion of an ITC following ADP reduces the incidence of PDPH and need for EBP

Secondary Outcomes

Whether leaving the ITC for >= 24hrs affected the incidence of PDPH and EBP compared to an ITC left in place for <24h

Statistics

• Chi-square test used for proportions
• Relative risk (RR), its standard error and 95% confidence interval (CI) were calculated
• P values <0.05 were considered significant

Results

• 153 patients had a PDPH and/or ADP
• 94 were recognised ADPs, 66 had an ITC, 28 did not
  • Only included these patients
• No significant difference in incidence of PDPH
• Following an ADP, 90/94 (95.7%) parturients developed PDPH. Of these, 41/90 (45.6%) required an EBP and 49/90 (54.4%) did not.
• In the ITC group, 33.3% of the parturients required an EBP in comparison to 67.9% in the non-ITC group (P <0.01, 95% CI 12.5 to 52.0)
• no significant difference between length of time catheter is left in and EBP

Conclusions/Discussions

• 70% of patients had an ITC placed following a recognised ADP. Much higher than other studies
  • However, these other studies were all published prior to 2009 ?because people concerned re safety
• ITC placement did not affect the incidence of PDPH but did reduce the need for an EBP (33 vs 68%).
• Length of time ITC catheter is placed does not impact on need for EBP
• Other factors may affect PDPH e.g.
  • patient obesity: ?morbidly obese patients reduced risk of PDPH
  • second stage pushing in vaginal delivery may increase PDPH
• Type and size of needle (bigger = greater incidence of PDPH)

Strengths and Limitations from the Study

Strengths

• Conducted in tertiary center in Australia – similar to our population
• Only included those with recognised ADPs (not those with presumed PDPH) therefore compared similar groups only differentiated by ITC

Limitations

• This was retrospective, single center, limited sample size
• Lots of similar studies. Most agree
• A larger study¹ (N=334) found no significant difference between spinal catheter and control group (USA)
• 18G Tuohy needle used, we use 16G
• A severity index of PDPH may have been useful ?perhaps patients in ITC group had less severe headaches and therefore didn’t require an EBP

Discussion from Journal Club Meeting (?Change of Practice)

A big limitation for this study was not having a severity index for headaches. The incidence of PDPH was similar across both groups, so the headache severity is the most likely reason that the ITC group received fewer EBP

At Kingston, we are a busy obstetric unit – would we have time to manage an ITC on labour ward? – as this would have to be managed by the anaesthetist only.

If the patient was a difficult epidural insertion/ was likely to deliver soon most people would insert the ITC.

Summary by Dr M Homsy. Journal Club Meeting 15 November 2018.