All posts by Cliff

Acute Med, All Updates, PHARM, Resus

Stroke thrombolysis outcomes from registry

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Data from a large national stroke registry are reported to show that in patients who received tPA, outcomes were worse the later it was given. From a registry of over a million patients, the study group included 58353 patients from 1395 sites treated after emergency department arrival with IV tPA within 4.5 hours of symptom onset. Reported odds ratios were small but statistically significant in this large sample size. There was a 4.9% rate of intracranial haemorrhage.
As there is no comparison with patients who did not receive tPA, one cannot conclude from this study that tPA is either beneficial or harmful. It may however be used as an argument that if you’re working in a centre where the patients are going to get the tPA, it’s advisable not to delay it.
Time to treatment with intravenous tissue plasminogen activator and outcome from acute ischemic stroke
JAMA. 2013 Jun 19;309(23):2480-8
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IMPORTANCE: Randomized clinical trials suggest the benefit of intravenous tissue-type plasminogen activator (tPA) in acute ischemic stroke is time dependent. However, modest sample sizes have limited characterization of the extent to which onset to treatment (OTT) time influences outcome; and the generalizability of findings to clinical practice is uncertain.

OBJECTIVE: To evaluate the degree to which OTT time is associated with outcome among patients with acute ischemic stroke treated with intraveneous tPA.

DESIGN, SETTING, AND PATIENTS: Data were analyzed from 58,353 patients with acute ischemic stroke treated with tPA within 4.5 hours of symptom onset in 1395 hospitals participating in the Get With The Guidelines-Stroke Program, April 2003 to March 2012.

MAIN OUTCOMES AND MEASURES: Relationship between OTT time and in-hospital mortality, symptomatic intracranial hemorrhage, ambulatory status at discharge, and discharge destination.

RESULTS: Among the 58,353 tPA-treated patients, median age was 72 years, 50.3% were women, median OTT time was 144 minutes (interquartile range, 115-170), 9.3% (5404) had OTT time of 0 to 90 minutes, 77.2% (45,029) had OTT time of 91 to 180 minutes, and 13.6% (7920) had OTT time of 181 to 270 minutes. Median pretreatment National Institutes of Health Stroke Scale documented in 87.7% of patients was 11 (interquartile range, 6-17). Patient factors most strongly associated with shorter OTT included greater stroke severity (odds ratio [OR], 2.8; 95% CI, 2.5-3.1 per 5-point increase), arrival by ambulance (OR, 5.9; 95% CI, 4.5-7.3), and arrival during regular hours (OR, 4.6; 95% CI, 3.8-5.4). Overall, there were 5142 (8.8%) in-hospital deaths, 2873 (4.9%) patients had intracranial hemorrhage, 19,491 (33.4%) patients achieved independent ambulation at hospital discharge, and 22,541 (38.6%) patients were discharged to home. Faster OTT, in 15-minute increments, was associated with reduced in-hospital mortality (OR, 0.96; 95% CI, 0.95-0.98; P < .001), reduced symptomatic intracranial hemorrhage (OR, 0.96; 95% CI, 0.95-0.98; P < .001), increased achievement of independent ambulation at discharge (OR, 1.04; 95% CI, 1.03-1.05; P < .001), and increased discharge to home (OR, 1.03; 95% CI, 1.02-1.04; P < .001).
CONCLUSIONS AND RELEVANCE: In a registry representing US clinical practice, earlier thrombolytic treatment was associated with reduced mortality and symptomatic intracranial hemorrhage, and higher rates of independent ambulation at discharge and discharge to home following acute ischemic stroke. These findings support intensive efforts to accelerate hospital presentation and thrombolytic treatment in patients with stroke.

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Acute Med, All Updates, ICU

TracMan results

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The TracMan trial – a multicentre randomised trial of early vs late tracheostomy in ICU patients – has been published, showing no difference in the primary outcome of mortality.
A review of the trial is posted on the excellent PulmCCM blog:

There was no proven difference between groups in 30-day mortality (30.8% early vs. 31.5% late, primary outcome), nor in any other outcome including 2-year mortality.

Patients getting early tracheostomies required fewer days of sedation, and there was a suggestion of a reduction of -1.7 ventilator days with early trach (mean 13.6 days vs 15.2 days, p=0.06). However, ICU stays were exactly equal at a median 13 days.

Also, 7% of patients had significant bleeding attributed to their tracheostomies (defined as needing IV fluids or another intervention); this amounted to 11 patients in the early group and 8 in the late group.

PulmCCM is an excellent free resource that will deliver critical care updates to your inbox. It has a number of other useful features, like free board review questions – highly recommended!
Effect of early vs late tracheostomy placement on survival in patients receiving mechanical ventilation: the TracMan randomized trial
JAMA. 2013 May 22;309(20):2121-9
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IMPORTANCE: Tracheostomy is a widely used intervention in adult critical care units. There is little evidence to guide clinicians regarding the optimal timing for this procedure.

OBJECTIVE: To test whether early vs late tracheostomy would be associated with lower mortality in adult patients requiring mechanical ventilation in critical care units.

DESIGN AND SETTING: An open multicentered randomized clinical trial conducted between 2004 and 2011 involving 70 adult general and 2 cardiothoracic critical care units in 13 university and 59 nonuniversity hospitals in the United Kingdom.

PARTICIPANTS: Of 1032 eligible patients, 909 adult patients breathing with the aid of mechanical ventilation for less than 4 days and identified by the treating physician as likely to require at least 7 more days of mechanical ventilation.

INTERVENTIONS: Patients were randomized 1:1 to early tracheostomy (within 4 days) or late tracheostomy (after 10 days if still indicated).

MAIN OUTCOMES AND MEASURES: The primary outcome measure was 30-day mortality and the analysis was by intention to treat.

RESULTS: Of the 455 patients assigned to early tracheostomy, 91.9% (95% CI, 89.0%-94.1%) received a tracheostomy and of 454 assigned to late tracheostomy, 44.9% (95% CI, 40.4%-49.5%) received a tracheostomy. All-cause mortality 30 days after randomization was 30.8% (95% CI, 26.7%-35.2%) in the early and 31.5% (95% CI, 27.3%-35.9%) in the late group (absolute risk reduction for early vs late, 0.7%; 95% CI, -5.4% to 6.7%). Two-year mortality was 51.0% (95% CI, 46.4%-55.6%) in the early and 53.7% (95% CI, 49.1%-58.3%) in the late group (P = .74). Median critical care unit length of stay in survivors was 13.0 days in the early and 13.1 days in the late group (P = .74). Tracheostomy-related complications were reported for 6.3% (95% CI, 4.6%-8.5%) of patients (5.5% in the early group, 7.8% in the late group).

CONCLUSIONS AND RELEVANCE: For patients breathing with the aid of mechanical ventilation treated in adult critical care units in the United Kingdom, tracheostomy within 4 days of critical care admission was not associated with an improvement in 30-day mortality or other important secondary outcomes. The ability of clinicians to predict which patients required extended ventilatory support was limited.

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All Updates, ICU, Resus

The non-intubation checklist

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no-sm

Scenario:
A 79 year old previously well female presents with loss of consciousness, having been found unresponsive by her daughter who saw her well one hour previously.
Examination reveals a GCS of E1V2M3 = 6 and reactive pupils with no lateralising signs. She is hypertensive. A VBG reveals a normal glucose and sodium and a pCO2 of 60 mmHg (7.9 kPa).
The emergency physician’s plan is to intubate and get a CT scan of her brain. This is explained to the daughter.
A no-brainer? You’d think so.

A consistent issue that recurs during discussions with UK emergency medicine colleagues is that of having to rely on anaesthesia and/or ICU colleagues for intubation of their patients in the ED. The pain comes not from disagreeing about who does the procedure or what drugs to use, but rather on the decision to intubate.
The refusal to intubate can stall or halt a resuscitation plan, delay care, result in risky transfers to the imaging suite, and even deny potential outcome-improving therapy (for example post-ROSC cooling). It can undermine team leadership and disrupt the team dynamic.
There are often different ways to ‘skin a cat’ and it is frequently helpful to invite the opinion of other critical care specialists. However, it is clear from multiple discussions with frustrated EM colleagues that the decision not to intubate is often influenced by non-clinical factors, most often ICU bed availability. Other times, it appears to be that the ‘gatekeeper’ to airway care (and to ICU beds) does not share the same appreciation of the clinical issues at stake. Examples here include the self-fulfilling pessimism post-ROSC based on inappropriate assignment of predictive value to neurological signs, and the assumption of non-treatable pathology in elderly patients presenting with coma.
The obvious solution to this is that the responsibility for managing the ‘A’ of ABC should not be delegated to non-emergency medicine personnel. Sadly, this is not achievable 24/7 in all UK departments right now for a number of awkward reasons.
So what’s a team leader to do when faced with a colleague’s refusal to intubate? The best approach would be to gently and politely persuade them to change their mind by stating some clinical facts that enable a shared mental model and agreed management plan, and to ensure the most senior available physicians are participating in the discussion.
Sometimes that fails. What next? Here’s a suggestion. This is slightly tongue-in-cheek but take away from it what you will.
It is imperative that the individual declining intubation appreciates the gravity of his or her decision. They must not be under the impression that they’ve done you (and the patient) a favour by giving their opinion after an ‘airway consult’. They have declined a resuscitative intervention requested by the emergency medicine team leader and should appreciate the consequences of this decision and the need to document it as such.
Perhaps say something along the lines of:

‘I see we haven’t managed to agree on this. We’ll just need you to complete the non-intubation form please for our quality improvement process. This will also help prevent your point being forgotten or misunderstood if we’re unlucky enough to face any complaints or litigation. I can fill it in on your behalf but I suspect you’d want to represent yourself as accurately as possible when documenting such a bold decision’

And here’s the form. It is provocative, cheeky, and in no way should really be used in its current form:

nonintubationchecklistsm
All Updates, ICU, Kids, PHARM, Resus, Trauma

Thenar eminence based medicine

A recent study showed superior effectiveness of one bag-mask ventilation style over another in novice providers. The technique recommended is the thenar eminence grip, in which downward pressure is applied with the thenar eminences while the four fingers of each hand pull the jaw upwards toward the mask.

Interestingly, in their crossover study in which the thenar emininence (TE) technique was compared with the traditionally taught ‘CE’ technique, they demonstrated a ‘sequence effect’. If subjects did TE first, they maintained good tidal volumes when doing CE. However if they did CE first, they achieved poor tidal volumes which were markedly improved when switching to TE.

The authors suggest: “A possible explanation for this sequence effect is that the TE grip is superior. When one used the TE grip first, he or she was more likely to learn how a good tidal volume “feels” and then more likely to apply good technique with the EC grip.“.

Some of us have been practicing and teaching this technique for a while. None have put it better than the brilliant Reuben Strayer of EM Updates in this excellent short video:

Emergency Ventilation in 11 Minutes from reuben strayer on Vimeo.

Efficacy of facemask ventilation techniques in novice providers
J Clin Anesth. 2013 May;25(3):193-7

STUDY OBJECTIVE: To determine which of two facemask grip techniques for two-person facemask ventilation was more effective in novice clinicians, the traditional E-C clamp (EC) grip or a thenar eminence (TE) technique.

DESIGN: Prospective, randomized, crossover comparison study.

SETTING: Operating room of a university hospital.

SUBJECTS: 60 novice clinicians (medical and paramedic students).

MEASUREMENTS: Subjects were assigned to perform, in a random order, each of the two mask-grip techniques on consenting ASA physical status 1, 2, and 3 patients undergoing elective general anesthesia while the ventilator delivered a fixed 500 mL tidal volume (VT). In a crossover manner, subjects performed each facemask ventilation technique (EC and TE) for one minute (12 breaths/min). The primary outcome was the mean expired VT compared between techniques. As a secondary outcome, we examined mean peak inspiratory pressure (PIP).

MAIN RESULTS: The TE grip provided greater expired VT (379 mL vs 269 mL), with a mean difference of 110 mL (P < 0.0001; 95% CI: 65, 157). Using the EC grip first had an average VT improvement of 200 mL after crossover to the TE grip (95% CI: 134, 267). When the TE grip was used first, mean VTs were greater than for EC by 24 mL (95% CI: -25, 74). When considering only the first 12 breaths delivered (prior to crossover), the TE grip resulted in mean VTs of 339 mL vs 221 mL for the EC grip (P = 0.0128; 95% CI: 26, 209). There was no significant difference in PIP values using the two grips: the TE mean (SD) was 14.2 (7.0) cm H2O, and the EC mean (SD) was 13.5 (9.0) cm H2O (P = 0.49).

CONCLUSIONS: The TE facemask ventilation grip results in improved ventilation over the EC grip in the hands of novice providers.

All Updates, ICU, Kids, PHARM, Resus, Trauma

RSI haemodynamics in the field

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intubated-prehosp-vol-iconThe noxious stimulus of laryngoscopy & tracheal intubation can precipitate hypertension, tachycardia, and intracranial pressure elevation, risking exacerbation of brain injury or haemorrhage. Physicians from an English Helicopter Emergency Medical Service examined the response of heart rate and blood pressure to prehospital rapid sequence intubation (RSI). While a retrospective study, the haemodynamic data were prospectively recorded and documented using standard monitor printouts, and time of intubation could be accurately determined by the onset of capnography recordings. Their standardised system documents blood pressure recordings every three minutes. Etomidate and suxamethonium were used for RSI.
They report their findings:


A hypertensive response occurred in 79% (70/89) of patients. MAP exceeded the upper limit of estimated intact cerebral autoregulation (150 mmHg) in 18% (16/89) of cases and 9% (8/89) of patients had a greater than 100% increase in MAP and/or SBP. A single hypotensive response occurred. A tachycardic response occurred in 58% (64/110) of patients and bradycardia was induced in one.

Of note, 97 of the 115 patients had injuries that included head trauma.
The authors note that opioids are often co-administered during in-hospital RSI and that this may offset the haemodynamic stimulation, while possible increasing the complexity of the procedure in the prehospital environment. They have modified their pre-hospital anaesthesia standard operating procedure to include the use of an opioid and will report the associated outcomes and complication rates ‘in due course’.
This is interesting and important stuff, and something we should all be looking at in our respective prehospital critical care services.
The haemodynamic response to pre-hospital RSI in injured patients
Injury. 2013 May;44(5):618-23
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BACKGROUND: Laryngoscopy and tracheal intubation provoke a marked sympathetic response, potentially harmful in patients with cerebral or cardiovascular pathology or haemorrhage. Standard pre-hospital rapid sequence induction of anaesthesia (RSI) does not incorporate agents that attenuate this response. It is not known if a clinically significant response occurs following pre-hospital RSI or what proportion of injured patients requiring the intervention are potentially at risk in this setting.

METHODS: We performed a retrospective analysis of 115 consecutive pre-hospital RSI’s performed on trauma patients in a physician-led Helicopter Emergency Medical Service. Primary outcome was the acute haemodynamic response to the procedure. A clinically significant response was defined as a greater than 20% change from baseline recordings during laryngoscopy and intubation.

RESULTS: Laryngoscopy and intubation provoked a hypertensive response in 79% of cases. Almost one-in-ten patients experienced a greater than 100% increase in mean arterial pressure (MAP) and/or systolic blood pressure (SBP). The mean (95% CI) increase in SBP was 41(31-51) mmHg and MAP was 30(23-37) mmHg. Conditions leaving the patient vulnerable to secondary injury from a hypertensive response were common.

CONCLUSIONS: Laryngoscopy and tracheal intubation, following a standard pre-hospital RSI, commonly induced a clinically significant hypertensive response in the trauma patients studied. We believe that, although this technique is effective in securing the pre-hospital trauma airway, it is poor at attenuating adverse physiological effects that may be detrimental in this patient group.

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All Updates, ICU, PHARM, Resus

Awake intubation

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I had some fun today getting intubated.
We used the Ambu aScope 2 and the Greater Sydney Area HEMS equipment and approach to airway management. I didn’t receive an antisialogogue or any analgesia or sedation.
The big learning point for me was how hard it was to anaesthetise the posterior part of my nasal cavity and nasopharynx. I thought the worst part would be any stimulation of my vocal cords or trachea with lidocaine or instrumentation, but this really was fine. Nebulised 2% lidocaine (the strongest concentration we have), atomised lidocaine (using a mucosal atomiser), and co-phenylcaine spray weren’t sufficient. I can see why people use pastes or gel to maintain mucosal contact while the lidocaine takes effect, but we don’t have those (yet). The best solution came from hooking up oxygen tubing to an iv cannula via a three way tap. Oxygen was run through at 2 l/min and lidocaine injected via the the three way tap. This enabled an atomised spray to be directed right onto the area concerned, and made the insertion of the nasotracheal tube more tolerable – although still unpleasant.
crazed-nutter-sm
The fact I could be intubated awake with reasonable topicalisation suggests most patients should tolerate it perhaps after even an analgesic dose of ketamine, eg. 30-40 mg in an adult. I suspect full dissocation would not be required, which is good for cooperation (“stick your tongue out sir”). I appreciate there are better agents, such as remifentanil or dexmedetomidine, but my area of interest is the retrieval setting – where I have neither the luxury of using these agents nor that of calling for anaesthetic back up.
Thanks to HEMS physicians Emily Stimson, Nirosha De Zoysa, Felicity Day, Chloe Tetlow, and Fergal McCourt for making it fun and safe.
Here’s the video:

Twitter has been helpful in gathering some advice, particularly from @DocJohnHinds:

All Updates, ICU

Difficult intubation on ICU

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icu-intub-iconA score to predict difficulty of intubation in ICU patients underwent derivation and validation in French ICUs. The main predictors included Mallampati score III or IV, obstructive sleep apnoea syndrome, reduced mobility of cervical spine, limited mouth opening, severe hypoxia, coma, and where the operator was a nonanesthesiologist.
The striking thing is the overall rate of difficult intubations, defined as three or more laryngoscopy attempts or taking over 10 minutes using conventional laryngoscopy(!) and the high rate of severe complications.
The incidence of difficult intubation was 11.3% (113 of 1,000 intubation procedures) in the original cohort and 8% (32 of 400 intubation procedures) in the validation cohort.
In the development cohort, overall complications occurred in 437 of 1,000 intubation procedures (43.7%), with 381 (38.1%) severe complications (26 cardiac arrests, 2.6%; five deaths, 0.5%; 274 severe collapses, 27.4%; 155 severe hypoxemia, 15.5%) and 112 (11.2%) moderate complications (15 agitations, 1.5%; 32 cardiac arrhythmias, 3.2%; 23 aspirations, 2.3%; 48 esophageal intubations, 4.8%; six dental injuries, 0.6%).
There is no comment on incidence of propofol use for induction; I was tempted to speculate whether it was implicated in any of the cardiac arrests – something we observe time and again in the critically ill – but the authors state: “The drugs used for intubation, in particular neuromuscular blockers, did not differ between groups… However, midazolam use was more frequent in case of difficult intubation.”
Capnography was used only in 46% of intubations, and there was no mention of checklist use. It is fascinating how some aspects of airway management that might be considered minimum and basic safety standards in some practice settings are not yet routine in other specialties or locations.
An interesting study, from which one of the take home messages for me has to be a resounding ‘Yikes!’.
Early Identification of Patients at Risk for Difficult Intubation in the Intensive Care Unit
Am J Respir Crit Care Med. 2013 Apr 15;187(8):832-9
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Rationale: Difficult intubation in the intensive care unit (ICU) is a challenging issue.

Objectives: To develop and validate a simplified score for identifying patients with difficult intubation in the ICU and to report related complications.

Methods: Data collected in a prospective multicenter study from 1,000 consecutive intubations from 42 ICUs were used to develop a simplified score of difficult intubation, which was then validated externally in 400 consecutive intubation procedures from 18 other ICUs and internally by bootstrap on 1,000 iterations.

Measurements and Main Results: In multivariate analysis, the main predictors of difficult intubation (incidence = 11.3%) were related to patient (Mallampati score III or IV, obstructive sleep apnea syndrome, reduced mobility of cervical spine, limited mouth opening); pathology (severe hypoxia, coma); and operator (nonanesthesiologist). From the β parameter, a seven-item simplified score (MACOCHA score) was built, with an area under the curve (AUC) of 0.89 (95% confidence interval [CI], 0.85-0.94). In the validation cohort (prevalence of difficult intubation = 8%), the AUC was 0.86 (95% CI, 0.76-0.96), with a sensitivity of 73%, a specificity of 89%, a negative predictive value of 98%, and a positive predictive value of 36%. After internal validation by bootstrap, the AUC was 0.89 (95% CI, 0.86-0.93). Severe life-threatening events (severe hypoxia, collapse, cardiac arrest, or death) occurred in 38% of the 1,000 cases. Patients with difficult intubation (n = 113) had significantly higher severe life-threatening complications than those who had a nondifficult intubation (51% vs. 36%; P < 0.0001).
Conclusions: Difficult intubation in the ICU is strongly associated with severe life-threatening complications. A simple score including seven clinical items discriminates difficult and nondifficult intubation in the ICU.

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All Updates, Kids, PHARM, Trauma

Intranasal ketamine for kids – 1mg / kg?

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A small pilot study on a convenience sample of children presenting to the emergency department with acute limb injury pain evaluated the use of intranasal ketamine(1).
Initial dose averaged 0.84 mg/kg and a third of the patients required a top up dose at 15 minutes, resulting in a total dose of about 1.0 mg/kg to provide adequate analgesia by 30 min for most patients. The authors suggest that this could guide investigators on an appropriate dose of IN ketamine for use in clinical trials.
Adverse events were all transient and mild.
Prior to administration, the ketamine was diluted with saline to a total volume of 0.5 mL and was administered as 0.25 mL per nare using a Mucosal Atomiser Device (MAD, Wolfe Tory Medical, Salt Lake City, UT, USA). According to the protocols in my Service, this device requires 0.1 ml to prime its dead space(2). It is unclear whether this factor may have affected the total dose delivered to the patient in this study.
1. Sub-dissociative dose intranasal ketamine for limb injury pain in children in the emergency department: A pilot study
Emerg Med Australas. 2013 Apr;25(2):161-7
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OBJECTIVE: The present study aims to conduct a pilot study examining the effectiveness of intranasal (IN) ketamine as an analgesic for children in the ED.

METHODS: The present study used an observational study on a convenience sample of paediatric ED patients aged 3-13 years, with moderate to severe (≥6/10) pain from isolated limb injury. IN ketamine was administered at enrolment, with a supplementary dose after 15 min, if required. Primary outcome was change in median pain rating at 30 min. Secondary outcomes included change in median pain rating at 60 min, patient/parent satisfaction, need for additional analgesia and adverse events being reported.

RESULTS: For the 28 children included in the primary analysis, median age was 9 years (interquartile range [IQR] 6-10). Twenty-three (82.1%) were male. Eighteen (64%) received only one dose of IN ketamine (mean dose 0.84 mg/kg), whereas 10 (36%) required a second dose at 15 min (mean for second dose 0.54 mg/kg). The total mean dose for all patients was 1.0 mg/kg (95% CI: 0.92-1.14). The median pain rating decreased from 74.5 mm (IQR 60-85) to 30 mm (IQR 12-51.5) at 30 min (P < 0.001, Mann-Whitney). For the 24 children who contributed data at 60 min, the median pain rating was 25 mm (IQR 4-44). Twenty (83%) subjects were satisfied with their analgesia. Eight (33%) were given additional opioid analgesia and the 28 reported adverse events were all transient and mild.
CONCLUSIONS: In this population, an average dose of 1.0 mg/kg IN ketamine provided adequate analgesia by 30 min for most patients

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2. Case report: prehospital use of intranasal ketamine for paediatric burn injury
Emerg Med J. 2011 Apr;28(4):328-9
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In this study, the administration of an intravenous ketamine formulation to the nasal mucosa of a paediatric burn victim is described in the prehospital environment. Effective analgesia was achieved without the need for vascular or osseous access. Intranasal ketamine has been previously described for chronic pain and anaesthetic premedication. This case highlights its potential as an option for prehospital analgesia.

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