A Japanese study of over 10,000 patients demonstrated improved neurological outcome in out-of-hospital cardiac arrest patients who were taken to hospitals designated as ‘critical care medical centres’, where neurologically favorable 1-month survival was greater [6.7% versus 2.8%, P < 0.001] despite a slightly longer call-hospital arrival interval [30.6 min vs 27.2, p < 0.001]. If return of spontaneous circulation was achieved pre-hospital, there was no difference in survival. It is unclear what factors, such as more interventional cardiology or therapeutic hypothermia, made the difference in the critical care centres.
Impact of transport to critical care medical centers on outcomes after
out-of-hospital cardiac arrest
Resuscitation. 2010 May;81(5):549-54
Category Archives: ICU
Stuff relevant to patients on ICU
Early CT and post-arrest outcome
A study on the early CT appearances of post-cardiac arrest patients shows two signs to be of importance – loss of boundary (LOB) between white and grey matter (at the level of the basal ganglia), and cortical sulcal effacement (SE). These features were more prevalent in patients who had > 20 minutes of arrest time and were associated with a worse neurological outcome at six months.
Early CT signs in out-of-hospital cardiac arrest survivors: Temporal profile and
prognostic significance
Resuscitation. 2010 May;81(5):534-8
Crystalloids vs colloids and cardiac output
It is said that when using crystalloids, two to four times more fluid may be required to restore and maintain intravascular fluid volume compared with colloids, although true evidence is scarce. The ratio in the SAFE study comparing albumin with saline resuscitation was 1:1.3, however.
A single-centre, single- blinded, randomized clinical trial was carried out on 24 critically ill sepsis and 24 non-sepsis patients with clinical hypovolaemia, assigned to loading with normal saline, gelatin 4%, hydroxyethyl starch 6% or albumin 5% in a 90-min (delta) central venous pressure (CVP)-guided fluid loading protocol. Haemodynamic monitoring using transpulmonary thermodilution was done each 30 min to measure, among other things, global end-diastolic volume and cardiac indices (GEDVI, CI). The reason sepsis was looked at was because of a suggestion in the SAFE study of benefit from albumin in the pre-defined sepsis subgroup.
Independent of underlying disease, CVP and GEDVI increased more after colloid than saline loading (P = 0.018), so that CI increased by about 2% after saline and 12% after colloid loading (P = 0.029).
Their results agree with the traditional (pre-SAFE) idea of ratios of crystalloid:colloid, since the difference in cardiac output increase multiplied by the difference in volume infused was three for colloids versus saline.
Take home message? Even though an outcome benefit has not yet been conclusively demonstrated, colloids such as albumin increase pre-load and cardiac index more effectively than equivalent volumes of crystalloid in hypovolaemic critically ill patients.
Greater cardiac response of colloid than saline fluid loading in septic and non-septic critically ill patients with clinical hypovolaemia
Intensive Care Med. 2010 Apr;36(4):697-701
Magnesium for subarachnoid haemorrhage
Symptomatic cerebral vasospasm occurs in nearly one-third of patients with aneurysmal subarachnoid hemorrhage and is a major cause of disability and mortality in this population.
Magnesium (Mg) acts as a cerebral vasodilator by blocking the voltage-dependent calcium channels.. Experimental studies suggest that Mg also inhibits glutamate release by blocking N-methyl-D-aspartate receptors, decreases intracellular calcium influx, and increases red blood cell deformability; all these changes may reduce the occurrence of cerebral vasospasm and minimise brain ischemic injury occurring after SAH.
One hundred and ten patients within 96 hours of admission for aneurysmal subarachnoid haemorrhage (SAH) were randomised to receive iv magnesium or placebo. Nimodipine was not routinely given. Twelve patients (22%) in the magnesium group and 27 patients (51%) in the control group had delayed ischemic infarction – the primary endpoint (p< .0020; odds ratio [OR], 0.28; 95% confidence interval [CI], 0.12– 0.64). Mortality was lower and neurological outcome better in the magnesium group but these results were not statistically significant.
Larger trials of magnesium in SAH are ongoing.
Prophylactic intravenous magnesium sulfate for treatment of aneurysmal subarachnoid hemorrhage: A randomized, placebo-controlled, clinical study
Crit Care Med. 2010 May;38(5):1284-90
Update September 2012:
A multicentre RCT showed intravenous magnesium sulphate does not improve clinical outcome after aneurysmal subarachnoid haemorrhage, therefore routine administration of magnesium cannot be recommended.
Magnesium for aneurysmal subarachnoid haemorrhage (MASH-2): a randomised placebo-controlled trial
Lancet 2012 July 7; 380(9836): 44–49 Free full text
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Background Magnesium sulphate is a neuroprotective agent that might improve outcome after aneurysmal subarachnoid haemorrhage by reducing the occurrence or improving the outcome of delayed cerebral ischaemia. We did a trial to test whether magnesium therapy improves outcome after aneurysmal subarachnoid haemorrhage.
Methods We did this phase 3 randomised, placebo-controlled trial in eight centres in Europe and South America. We randomly assigned (with computer-generated random numbers, with permuted blocks of four, stratified by centre) patients aged 18 years or older with an aneurysmal pattern of subarachnoid haemorrhage on brain imaging who were admitted to hospital within 4 days of haemorrhage, to receive intravenous magnesium sulphate, 64 mmol/day, or placebo. We excluded patients with renal failure or bodyweight lower than 50 kg. Patients, treating physicians, and investigators assessing outcomes and analysing data were masked to the allocation. The primary outcome was poor outcome—defined as a score of 4–5 on the modified Rankin Scale—3 months after subarachnoid haemorrhage, or death. We analysed results by intention to treat. We also updated a previous meta-analysis of trials of magnesium treatment for aneurysmal subarachnoid haemorrhage. This study is registered with controlled-trials.com (ISRCTN 68742385) and the EU Clinical Trials Register (EudraCT 2006-003523-36).
Findings 1204 patients were enrolled, one of whom had his treatment allocation lost. 606 patients were assigned to the magnesium group (two lost to follow-up), 597 to the placebo (one lost to follow-up). 158 patients (26·2%) had poor outcome in the magnesium group compared with 151 (25·3%) in the placebo group (risk ratio [RR] 1·03, 95% CI 0·85–1·25). Our updated meta-analysis of seven randomised trials involving 2047 patients shows that magnesium is not superior to placebo for reduction of poor outcome after aneurysmal subarachnoid haemorrhage (RR 0·96, 95% CI 0·86–1·08).
Interpretation Intravenous magnesium sulphate does not improve clinical outcome after aneurysmal subarachnoid haemorrhage, therefore routine administration of magnesium cannot be recommended.
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Current Controversy in RSI
A review article in Anesthesia and Analgesia provides a summary of the literature surrounding RSI controversies.
- Should a pre-determined dose of induction drug be given or should it be titrated to effect prior to giving suxamethonium?
- Should fast acting opioids be coadministered to blunt the pressor response?
- What is the optimal dose of suxamethonium?
- Should defasciculating doses of neuromuscular blocking drugs be given?
- What is the ‘priming’ technique with rocuronium and is it necessary?
- Is it really bad to bag-mask ventilate the patient after induction prior to intubation? Which patients might this benefit?
- Should patients with full stomachs be anaesthetised sitting up, supine, or head down?
- Is cricoid pressure a good or a bad thing?
Not surprisingly the jury is still out on these, which is of course why they remain ‘controversies’. The review article provides a readable, interesting, and up to date summary of the evidence to date.
Rapid Sequence Induction and Intubation: Current Controversy
Anesth Analg. 2010 May 110(5):1318-25
Inhaled NPA
A case is reported of a stroke patient who aspirated his nasopharyngeal airway, resulting in coughing and desaturation. After iv propofol and topical anaesthesia to the oropharynx and hypopharynx, it was seen on laryngoscopy to be within the trachea but could not be retrieved with Magill forceps. Instead, his doctors inserted a well lubricated 14 Fr foley catheter through the lumen of the tube, inflated the balloon, and pulled it out.
Retrieval of Aspirated Nasopharyngeal Airway Using Foley Catheter
Anesth Analg. 2010 Apr;110(4):1245-6
Single-use Metal Laryngoscope Blades
In a randomised study of more than 1072 patients for emergency intubation using rapid sequence induction, single-use metal blades were associated with fewer failed first attempts and fewer poor grade laryngeal views than reusable metal blades. Improved illumination may be a factor.
Comparison of Single-use and Reusable Metal Laryngoscope Blades for Orotracheal Intubation during Rapid Sequence Induction of Anesthesia
Anesthesiology. 2010 Feb;112(2):325-32
NIV in chest trauma
ICU patients with thoracic trauma who had no other indication for intubation than marked hypoxaemia (pO2/FiO2 < 200 mmHg) were randomised to intubation vs non-invasive ventilation (NIV). Analgesia was via epidural bupivacaine / fentanyl or iv remifentanil. Numbers are small (total 50 patients) - partly because the trial was stopped early due to large difference in the outcome of tracheal intubation between the two groups favouring NIV. Length of hospital stay was significantly shorter in the NIV group but there was no survival difference.
Noninvasive ventilation reduces intubation in chest trauma-related hypoxemia: a randomized clinical trial
Chest. 2010 Jan;137(1):74-80
The right antibiotic in septic shock makes a massive difference
A retrospective review of appropriate vs inappropriate antimicrobial therapy was undertaken in over four thousand septic shock patients from multiple centres. In terms of definitions, the authors state:
“Appropriate antimicrobial therapy was considered to have been initiated if an antimicrobial with in vitro activity appropriate for the isolated pathogen or pathogens (or in the case of culture-negative septic shock, an antimicrobial or antimicrobial agent concordant with accepted international norms for empiric therapy and modified to local flora) was either the first new antimicrobial agent with which therapy was started after the onset of recurrent or persistent hypotension or was initiated within 6 h of the administration of the first new antimicrobial agent. Otherwise, inappropriate therapy was considered to have been initiated.”
The results are striking: survival rates after appropriate and inappropriate initial therapy were 52.0% and 10.3%, respectively (odds ratio [OR], 9.45; 95% CI, 7.74 to 11.54; p < 0.0001).
A multivariable logistic regression analysis of possible factors that may affect outcome showed the appropriateness of the initial antimicrobial therapy remained most strongly associated with outcome (OR, 8.99; 95% CI, 6.60 to 12.23; p < 0.0001) among all the risk factors assessed.
Initiation of Inappropriate Antimicrobial Therapy Results in a Fivefold Reduction of Survival in Human Septic Shock
Chest. 2009 Nov;136(5):1237-48
N.B. This work was done by the same authors who brought us the study that showed the earlier antibiotics were given to hypotensive septic patients, the better the outcome:
Kumar A, Roberts D, Wood KE, et al. Duration of hypotension before initiation of effective antimicrobial therapy is the critical determinant of survival in human septic shock. Crit Care Med 2006; 34:1589-1596
CT cervical spine in obtunded trauma patients
Prolonged collar use and spinal immobilisation in ICU patients can contribute to pressure sores, increased intracranial pressure, venous obstruction, difficulties with airway management, difficulties with central venous access, respiratory complications, and DVT, so a reliable investigation to rule out unstable cervical spine injury is required. Several studies demonstrate the high sensitivity of CT, and now a prospective study from Canada attempts to lend further support to this.
Comparing against their chosen gold standard of dynamic radiography, ie. flexion/extension views (F/E) in 402 patients who received both tests, there was one case of injury detected by F/E but not by CT, leading to quoted sensitivity of 99.75%. However this negative CT turned out to be a reporting error – the scan, which the authors include in their article, was clearly abnormal.
One weakness of this study is that they excluded patients who died on ICU. More worrying are the stats quoted. The authors stat ‘four hundred one patients (99.75%) had normal CT and F-E images facilitating clinical clearance of their C-spine and discontinuation of spinal precautions‘. So in other words, there was only one patient in their series of 402 with an injury (according to the gold standard), and this was missed. The sensitivity is therefore zero percent, not 99.75%. What seems to be a further error is the reporting in a table of 401 patients who had ‘Positive CT and Negative F-E’, which if true, would give a specificty of zero too!
This paper covers an important topic for intensivists but it seems to me to be too flawed to add meaningfully to the existing evidence that necks can be ‘cleared’ by CT in patients without signs of cervical spine injury, in whom it has been said that the risks of prolonged collar use and immobilisation may outweigh the risks of missed cervical injury.
Cervical spine clearance in obtunded blunt trauma patients: a prospective study
J Trauma. 2010 Mar;68(3):576-82