Over the last few episodes we’ve talked about the use of vasopressors and their utility in resuscitation. It is a commonly held belief that giving vasopressors peripherally puts patients at high risk of extravasation and secondary skin necrosis. In an ideal world patients would have a central line placed and then have their vasopressors commenced, sadly life in the ED doesn’t always mean that time permits this luxury.
If you’re presented with a patient that requires vasopressors should you wait until that central access is gained or is it acceptable to commence peripheral vasopressors, obtain central access as quickly as is feasible and then convert over?
An RCT of just over 250 patients in 2013 looked at the complication rate when patients were randomly assigned to either peripheral iv access or central as their initial venous access in ITU. They showed a significant increase in complications (all be it non life threatening) when choosing the peripheral route and concluded ‘In ICU patients with equal central or peripheral venous access requirement, central venous catheters should preferably be inserted: a strategy associated with less major complications’. They defined complications with a relatively long list of events, including such things as a need to resite the iv site and difficulties insertion (defined as >2 attempts in gaining a peripheral iv) but included extravasation of fluid. This study wasn’t specifically looking at vasopressor infusions and looked at complications over a 28 day period.
This however isn’t the situation we’re faced with in ED, what we’re deciding is whether the vasopressors should be delayed to gain the gold standard access to ensure it’s safe delivery or if the risk is small enough to warrant commencing vasopressors before central access is gained.
A recent paper by Loubani, published in the Journal of Critical Care, gives us a greater understanding of the sort of risks we might be taking. The authors looked at adults with a spontaneous circulation who were receiving vasopressors either via a central venous catheter or peripherally. It was a systematic review of all published reports of both local tissue injury and extravasation. This obviously leads the paper wide open to reporter bias but as the authors state, current practice and concern over peripheral vasopressor is based only upon case reports and expert opinion.
The paper reviewed 325 separate events of local tissue injury or extravasation. They found the average duration of vasopressor infusion to be 56 hours prior to local injury occurring with a secondary major disability reported in 4.4% of events.
They also looked at the sites in which these events occurred and noted that the saphenous vein was the most commonly reported area of complications but that as a rule peripheral sites were more commonly affected than more proximal sites.
Whilst it’s difficult to make a firm statement about the safety or lack of it for administering peripheral iv vasopressors it’s probably reasonable that in the patient requiring urgent vasopressors, when the ability to gain central access will interfere with time critical interventions, running an infusion through a peripheral access (sited as proximally on the body as possible) for as short a period a time before switching to a central line seems reasonable. It’s key to make sure that the cannula is well sited and there are regular checks to ensure there isn’t any local damage or extravasation during its limited use. As with all of medicine it’s about weighing up the potential risks against the benefits to the patient.
The second paper we looked at by Benoit, published in Resuscitation, looked at outcomes when comparing patients in cardiac arrest who had EMS ET tubes placed compared with the use of supraglottic airway devices.
This was another systematic review and they found 10 relevant papers, including over 70, 000 patients and found some interesting associations.
Patients who received ET tubes rather than supraglottic devices had significantly better chances of ROSC, survival to hospital admission and neurologically intact survival to hospital discharge.
The authors point out that the 10 articles were all observational cohort studies with relatively low level evidence and that there will have been a number of confounders that could have influenced the results.
So although this isn’t necessarily a game changer, it’s interesting to see the association of patients receiving an ET tube in cardiac arrest, with a greater survival which isn’t widespread current teaching in the UK. It could of course be that seemingly simple airways led the EMS providers to feel more confident in performing an intubation, there may have competency levels that led those with a greater skill set to perform intubation which may reflect a greater underlying level of care that those patients received, or it may be that the benefit in ventilation and oxygenation inferred by intubation in arrests is genuine. It’s fair to say that more work will be needed in this area until we truly understand the relationship.
That’s it for this time, we’ll be back soon with some more Resuscitation based EBM and maybe I’ll bump into you next week in Chicago!!!!
Loubani, Osama M., and Robert S. Green. “A systematic review of extravasation and local tissue injury from administration of vasopressors through peripheral intravenous catheters and central venous catheters.” Journal of critical care 30.3 (2015): 653-e9.
Ricard JD, Salomon L, Boyer A, Thiery G, Meybeck A, Roy C, et al. Central or peripheral catheters for initial venous access of ICU patients: a randomized controlled trial. Crit Care Med 2013;41:2108–15.