A study in Injury looks at what happens to our patients´ blood pressures when we do rapid sequence inductions for intubation. With all the talk of ´permissive hypotension´ in modern trauma management this could be important.
Trauma- or shock-RSI, wether in the ED or in the field, mostly relies on Ketamine or Etomidate induction as they preserve sympathetic tone and and largely maintain respiratory drive. For the same reasons we often omit using opioids in RSI. Opioids reduce sympathetic drive and risk decompensating a really crook patient. We also don´t want to take away the respiratory drive in case we screw up the intubation… So, we are probably reasonably good at avoiding the hypotension we know a marginal patient won´t tolerate.✝
But what of hypertension? Laryngoscopy potently provokes a neuroendocrine sympathetic response that can send the blood pressure through the roof. Modern trauma management emphasise permissive hypotension in order to minimise bleeding and to prevent clots from popping. How does our RSI protocols live up to that?
The study from Kent, Surrey and Sussex air ambulance (KSS) looks at what happens with our patients´ blood pressure during a fairly typical prehospital RSI. They looked at haemodynamic data from 115 trauma RSI patients.
The KSS protocol uses, depending on the patients condition, 0-0,3 mg/kg etomidate for induction, then 1,5 mg/kg succinylcholine for paralysis before intubation. In some patients analgesia was provided, before intubation, with ketamine 0,5-1 mg/kg.
79% of the patients had an hypertensive event.
Mean arterial pressure exceeded 150 mmHg in 18% of patients.
9% had an increase in MAP and/or SBP of more than 100%
Only one hypotensive event was recorded.
The RSIs performed in this study with a protocol based on etomidate for induction agent resulted in significant hypertension.
Study lives here:
Injury. 2013 May;44(5):618-23. doi: 10.1016/j.injury.2012.03.019. Epub 2012 Apr 6. The haemodynamic response to pre-hospital RSI in injured patients. Perkins ZB, Gunning M, Crilly J, Lockey D, O’Brien B.
✝ This works. Some of the time anyway… In the really marginal shock/trauma patients ketamine is just as dangerous and likely to produce hypotension as any other induction agent. The experienced ED-doc or anesthetist is just as uncomfortable giving ketamine as she/he would be giving thio or propofol. For more on this listen to the best podcast about trauma resuscitation ever made. Here.