Less RSI desaturation with Roc

Some of my pre-hospital critical care colleagues in the UK exclusively use rocuronium in preference to suxamethonium for rapid sequence induction (RSI) of anaesthesia in critically ill patients. I couldn’t see a good reason to switch although now there’s some evidence that adds to the argument.

The muscle fasciculations caused by the depolarising effect of suxamethonium may increase oxygen consumption, which may shorten the apnoea time before desaturation. Non-depolarising neuromuscular blockers such as rocuronium should allow a longer apnoea time after RSI. In addition, drugs which reduce fasciculations (such as lidocaine and fentanyl) should delay the the onset of desaturation when given prior to suxamethonium.

A large dose of Roc

These hypotheses were tested in a blinded, randomised controlled trial in 60 ASA-1 or -2 patients, who were scheduled for elective surgery under general anaesthesia. All patients received 2mg/kg propofol. One group was randomised to receive suxamethonium 1.5 mg/kg, a second group received rocuronium 1mg/kg plus lidocaine 1.5mg/kg and fentanyl 2mcg/kg, and a third group was given suxamethonium 1.5 mg/kg plus lidocaine 1.5mg/kg and fentanyl 2mcg/kg. The facemask was removed 50 seconds after the neuromuscular blocker was given and patients were intubated; the tube was then left open to air until desaturation to 95% occurred, which was timed.

Desaturation occurred significantly sooner in the suxamethonium-only group, followed by the sux/lido/fentanyl group, followed by the roc/lido/fentanyl group.

Of course these results are not necessarily directly applicable to the critically ill patient, and in this study there was no direct comparison between induction agent + rocuronium only and induction agent + suxamethonium only. Nevertheless the argument that suxamethonium-induced muscle fasciculations contribute to an avoidable increase in oxygen consumption is persuasive.

Effect of suxamethonium vs rocuronium on onset of oxygen desaturation during apnoea following rapid sequence induction
Anaesthesia. 2010 Apr;65(4):358-61

NICE Alcohol Guidelines

The UK’s National Institute for Health and Clinical Excellence (NICE) has produced guidelines on alcohol-related physical complications, including alcohol withdrawal syndrome, Wernicke’s encephalopathy, acute and chronic pancreatitis, and acute alcoholic hepatitis.

The acute alcohol withdrawal section includes the following recommendations:

Offer drug treatment for the symptoms of acute alcohol withdrawal, as follows:

  • Consider offering a benzodiazepine or carbamazepine.
  • Clomethiazole may be offered as an alternative to a benzodiazepine or carbamazepine. However, it should be used with caution, in inpatient settings only and according to the summary of product characteristics.
  • Follow a symptom-triggered regimen for the drug treatment of acute alcohol withdrawal in people who are:
    • in hospital or
    • in other settings where 24-hour assessment and monitoring are available.

Treatment for delirium tremens or seizures

  • Offer oral lorazepam as first-line treatment for delirium tremens. If symptoms persist or oral medication is declined, give parenteral lorazepam, haloperidol or olanzapine.
  • For people with alcohol withdrawal seizures, consider offering a quick-acting benzodiazepine (such as lorazepam) to reduce the likelihood of further seizures.
  • If delirium tremens or seizures develop in a person during treatment for alcohol withdrawal, review their withdrawal drug treatment.
  • Do not offer phenytoin to treat alcohol withdrawal seizures.

Alcohol-use disorders: Diagnosis and clinical management of alcohol-related physical complications
Quick reference summary

MRA for PE not very good

Wouldn’t it be great to have a reliable, radiation-free way to diagnose pulmonary embolism? Unfortunately, Magnetic Resonance Angiography is not it. In a study of 371 patients across 7 hospitals from the PIOPED III (Prospective Investigation of Pulmonary Embolism Diagnosis III) investigators, the test was technically inadequate because of poor-quality images in 25% of cases. In those tests that were readable, the sensitivity was only 78%.

Gadolinium-Enhanced Magnetic Resonance Angiography for Pulmonary Embolism: A Multicenter Prospective Study (PIOPED III)
Ann Intern Med. 2010 Apr 6;152(7):434-43

High-Dose N-Acetylcysteine Therapy for H1N1

A case report describes the improvement of a critically ill patient with H1N1 ‘flu after the administration of N-acetylcysteine in a dose similar to that used to treat paracetamol (acetaminophen) overdose.
Influenza virus induces reactive oxygen species that activate nuclear factor kappa B to produce cytokines. High-dose N-acetylcysteine, an antioxidant, is thought to reduce the production of this cytokine storm which contributes to the lethality of influenza. More studies are clearly needed.

High-Dose N-Acetylcysteine Therapy for Novel H1N1 Influenza Pneumonia
Ann Intern Med. 2010 May 18;152(10):687-8

Steroids for pneumonia?

Steroids are useful in asthma and COPD exacerbations, which are lung problems. Pneumonia is a lung infection, so steroids might help there too right? Erm… no.

A double blind randomised controlled trial demonstrated no benefit from steroids (prednisolone) versus placebo in patients with community acquired pneumonia, and late therapaeutic failure (>72 h after admission) was more common in the prednisolone group.
Efficacy of Corticosteroids in Community-acquired Pneumonia: A Randomized Double-Blinded Clinical Trial
Am J Respir Crit Care Med. 2010 May 1;181(9):975-82

Pre-hospital RSI successes

A couple of papers in Prehospital Emergency Care this month contribute to the pre-hospital airway management / rapid sequence intubation (RSI) literature.

Intensive physician oversight of a pre-hospital RSI program increased the prescription of post-intubation morphine and midazolam, and decreased vecuronium use, although did not significantly increase the successful intubation rate in a before-and-after study. There was also an improvement in patient selection for RSI.

Effect of intensive physician oversight on a prehospital rapid-sequence intubation program
Prehosp Emerg Care. 2010 Jul-Sep;14(3):310-6

A prospective study examined intubation success rates and peri-intubation hypoxaemia in critical care transport (CCT) services in North America, whose services are mainly crewed by registered nurses (RNs) and emergency medical technicians–paramedic (EMT-Ps).

There was a mixture of pre-hospital and interhospital work: 51.9% of the 603 patients studied were intubated at the trauma scene, 27% were intubated inside a hospital, and interestingly 21.1% were intubated inside a vehicle (most of which were helicopters).

Neuromuscular blockade was used to facilitate intubation in only 428 patients (71%). Endotracheal intubation (ETI) was successful in 582 patients (96.5% of 603, 95% CI 94.7-97.8%). There was a greater need (p < 0.001) for multiple attempts at ETI when CCT crews performed the procedure in transport (37.3%) as compared with rate of requirement for multiple ETI attempts while in hospital (16.6%) or on scene (19.4%). Logistic regression identified a three-fold increase in the odds of requiring multiple attempts for intratransport ETI as compared with in-hospital ETI (OR 3.0, 95 CI 1.7–5.2, p < 0.001). 21 patients (3.5%) could not be intubated by the CCT crews resulting in a number of different rescue modalities including 3 cricothyroidotomies. At least there were no unrecognised oesophageal intubations. There were low rates of new hypoxaemia but peri-ETI SpO2 was only recorded for 494 patients (82%).

Airway management success and hypoxemia rates in air and ground critical care transport: a prospective multicenter study
Prehosp Emerg Care. 2010 Jul-Sep;14(3):283

Pre-hospital chest escharotomy

Two cases are described in Pre-hospital Emergency Care of severely burned patients who were impossible to adequately ventilate after tracheal intubation until they underwent escharotomy by a pre-hospital physician.
The review that follows reminds us of some intersting escharotomy facts:

  • circumferential extremity burns can cause limb ischaemia
  • abdominal burns can cause elevated intra-abdominal pressure and ischemic bowel
  • neck burns can cause tracheal and jugular venous compression
  • chest burns can cause respiratory compromise
  • one previous study showed that chest and abdominal escharotomies significantly decreased intra-abdominal pressure, retention of carbon dioxide, and central venous and inferior vena caval pressures while significantly increasing serum oxygen concentration and systolic blood pressure.
  • escharotomies may be performed on multiple body parts, including the extremities, the digits, the chest, the abdomen, the neck, and the penis
  • neck escharotomy is a relatively simple procedure that involves an incision of the skin eschar longitudinally in the anterior midline from the chin to the sternal notch
  • although different ways of doing chest escharotomies have been described, in the two reported cases in this article the procedure only involved longitudinal incisions, with good immediate effect.

Of note, neither of the physicians concerned had seen or done an escharotomy before. I’m adding this to my list of life-saving surgical interventions that are technically straightforward to perform, cannot always wait for another specialist to do, and happen too rarely to train for in the traditional way (ie being taught on a patient under supervision prior to the first time you do one).

Out-of-hospital chest escharotomy: a case series and procedure review
Prehosp Emerg Care. 2010 Jul-Sep;14(3):349-54

Two tier trauma team

Rather than activating a full trauma team based on traditional criteria, this team devised a two tier approach; if there were no positive anatomical or physiological criteria, a trauma team ‘consult’ approach was adopted, in which the patient was evaluated by emergency department and general surgery doctors only.

Of 1144 trauma activations, 468 (41%) were full trauma and 676 (59%) were consult trauma activations.. Sensitivity of the triage tool for the major trauma outcome (ISS>15, death, or needing critical care or urgent surgery) was 83%, specificity was 68%, undertriage was 3% and overtriage was 27%. There were no deaths in undertriaged patients.
This is an important study that has the potential to improve resource utilisation and even patient experience.

Prospective evaluation of a two-tiered trauma activation protocol in an Australian major trauma referral hospital
Injury. 2010 May;41(5):470-4

Military pre-hospital thoracotomy

Military doctors in Afghanistan reviewed their experience of thoracotomy done within 24 hours of admission to their hospital. The ballistic nature of thoracic penetrating trauma (mainly Afghan civilians without body armour) differs from the typical knife-wound related injury seen in survivors of thoracotomy reported in the pre-hospital literature.

Six of the patients presented in cardiac arrest – four PEA and two asystole. One of the PEA patients survived; this patient had sustained a thoracoabdominal GSW and had arrested 8 minutes from hospital. Following emergency thoracotomy, aortic control, and concomitant massive transfusion, return of spontaneous circulation (ROSC) was achieved and damage control surgery undertaken in both chest and abdomen.

The two patients in asystole had sustained substantial pulmonary and hilar injuries, and ROSC was never achieved. The patients in PEA all had arrested as a consequence of hypovolaemia from solid intra-abdominal visceral haemorrhage. All patients in PEA had ROSC achieved, albeit temporarily.

Following thoracotomy, patients required surgical manoeuvres such as pulmonary hilar clamping, packing and temporary aortic occlusion; hypovolaemia was the leading underlying cause of the cardiac arrest. These factors lead the authors to conclude that although isolated cardiac wounds do feature in war, they are unusual and the injury pattern of casualties in conflict zones are often complex and multifactorial.

Is pre-hospital thoracotomy necessary in the military environment?
Injury. 2010 Jul;41(7):1008-12