Anaesthesia
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“Inhalational anaesthetic agents are chlorofluorocarbons, ‘greenhouse gases’ that have between 349 (sevoflurane) and 3714 (desflurane) times the global warming potential over a 20 year time horizon of carbon dioxide (isoflurane 1401), equivalent to driving a car 18 (sevoflurane) to ~350 miles (desflurane) per hour of anaesthetic use (isoflurane 30 miles); these figures do not account for the additional carbon cost of heating desflurane vaporisers. Together with nitrous oxide, inhalational anaesthetic agents contribute ~2.5% of the 22.8 million tonnes of carbon dioxide equivalents the NHS produces annually.” - White
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What did they find?
This review by Patel, Robertson & McConachie identified 21 published cases of inadvertent spinal TXA administration. Notably 10 patients died, and almost all suffered life-threatening side effects.
What are the common signs?
- Block failure.
- Severe back and buttock pain (universal).
- Seizures.
- HT, tachycardia, arrhythmias, CVS collapse.
How should it be managed?
There are three components to managing intrathecal TXA:
- Treating TXA-induced seizures with anticonvulsants: magnesium; benzodiazepines; barbiturates (thiopentone); phenytoin; possibly propofol. Thiopentone infusion was frequently required to terminate seizures.
- Mitigate TXA neurotoxic effects: maintain head-up; CSF lavage to dilute TXA, infusing crystalloid at an interspace higher than an IT needle draining CSF, 10mL for 10mL, repeated up to 4 times.
- Haemodynamic monitoring & support
How does this happen?
In almost all cases ampoule identification error was the primary cause.
Human factor contributions identified were:
- Failure to check ampoule label.
- Similar ampoule appearance.
- Spinal catheter mistaken for IV (1).
- Lack of drug handling and storage policies.
- Storage of tranexamic acid with LA or lack of physical separation.
- Underestimating potential for error.
summary"All errors could have been prevented..."
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A sobering editorial...
- Since 2009 there has been a dramatic increase in reported cases of intrathecal tranexamic acid (TXA), parallel to increasing intraoperative TXA use.
- TXA is powerfully neurotoxic.
- Spinal TXA has a mortality rate > 50%, and high incidence of permanent neurological injury in survivors.
- Almost always results from a drug swap error.
- Because both TXA and bupivacaine are made by many manufacturers, there are many different ampoule designs and drug presentations.
- Risk of harm from TXA error is probably ~ 1 in 10,000 spinals.
- TXA should be physically separated from common spinal drugs and we should consider discarding orphaned ampoules rather than attempting to return to the box.
- Stop and visualise the consequences after your own theoretical spinal drug error: facing the patient, family, colleagues, hospital, regulators...
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Multicenter Study
The effect of fresh gas flow during induction of anaesthesia on sevoflurane usage: a quality improvement study.
Modest reductions in fresh gas flow at the beginning of anaesthesia induction results in meaningful reduction in sevoflurane consumption.
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Randomized Controlled Trial
A randomised controlled trial of phenylephrine and noradrenaline boluses for treatment of postspinal hypotension during elective caesarean section.
Phenylephrine & noradrenaline show similar incidence of bradycardia when used for postspinal hypotension prophylaxis during Caesarean section.
pearl