Tag Archives: critical care

Acute Med, All Updates, ICU, Resus

Vasoactive drugs in cardiogenic shock

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I’m always on the look-out for evidence to guide vasoactive drug therapy, an area where much dogma is spouted by many who have not read the literature. Here’s a small (note: pilot) study comparing two strategies for cardiogenic shock. The higher heart rate and lactate with epinephrine (adrenaline) are consistent with the findings of the great CAT study; this is of interest, but not necessarily clinically significant nor practice changing.

OBJECTIVE: There is no study that has compared, in a randomized manner, which vasopressor is most suitable in optimizing both systemic and regional hemodynamics in cardiogenic shock patients. Hence, the present study was designed to compare epinephrine and norepinephrine-dobutamine in dopamine-resistant cardiogenic shock.
DESIGN: Open, randomized interventional human study.
SETTING: Medical intensive care unit in a university hospital.
PATIENTS: Thirty patients with a cardiac index of <2.2 L/min/m and a mean arterial pressure of <60 mm Hg resistant to combined dopamine-dobutamine treatment and signs of shock. Patients were not included in cases of cardiogenic shock secondary to acute ischemic events such as myocardial infarction. Noninclusion criteria also included immediate indication of mechanical assistance.
INTERVENTIONS: Patients were randomized to receive an infusion of either norepinephrine-dobutamine or epinephrine titrated to obtain a mean arterial pressure of between 65 and 70 mm Hg with a stable or increased cardiac index.
MAIN RESULTS: Both regimens increased cardiac index and oxygen-derived parameters in a similar manner. Patients in the norepinephrine-dobutamine group demonstrated heart rates lower (p<.05) than those in the epinephrine group. Epinephrine infusion was associated with new arrhythmias in three patients. When compared to baseline values, after 6 hrs, epinephrine infusion was associated with an increase in lactate level (p<.01), whereas this level decreased in the norepinephrine-dobutamine group. Tonometered PCO2 gap, a surrogate for splanchnic perfusion adequacy, increased in the epinephrine-treated group (p<.01) while decreasing in the norepinephrine group (p<.01). Diuresis increased in both groups but significantly more so in the norepinephrine-dobutamine group, whereas plasma creatinine decreased in both groups.
CONCLUSIONS: When considering global hemodynamic effects, epinephrine is as effective as norepinephrine-dobutamine. Nevertheless, epinephrine is associated with a transient lactic acidosis, higher heart rate and arrhythmia, and inadequate gastric mucosa perfusion. Thus, the combination norepinephrine-dobutamine appears to be a more reliable and safer strategy.

Comparison of norepinephrine-dobutamine to epinephrine for hemodynamics, lactate metabolism, and organ function variables in cardiogenic shock. A prospective, randomized pilot study
Crit Care Med. 2011 Mar;39(3):450-5

All Updates, ICU, Resus

Disposable flexible intubating scope

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There is now a single use flexible intubating device that compares favourably with conventional fibreoptic devices. It does not have fibreoptic cables, but rather has a small camera at its tip illuminated by an LED. The image is transmitted via a cable in the device to a reusable screen. Dr Cook’s team in Bath, England have an extensive track record of evaluating new airway devices, and they report their assessment of this gadget in a manikin-based study. I think this may extend the airway management options to departments or teams for whom the cost and maintenance of conventional fibreoptic equipment is prohibitive.

We compared the Ambu aScope™ with a conventional fibrescope in two simulated settings. First, 22 volunteers performed paired oral and nasal fibreoptic intubations in three different manikins: the Laerdal Airway Trainer, Bill 1 and the Airsim (a total of 264 intubations). Second, 21 volunteers intubated the Airway Trainer manikin via three supraglottic airways: classic and intubating laryngeal mask airways and i-gel (a total of 66 intubations). Performance of the aScope was good with few failures and infrequent problems. In the first study, choice of fibrescope had an impact on the number of user-reported problems (p=0.004), and user-assessed ratings of ease of endoscopy (p<0.001) and overall usefulness (p<0.001), but not on time to intubate (p=0.19), or ease of railroading (p=0.72). The manikin chosen and route of endoscopy had more consistent effects on performance: best performance was via the nasal route in the Airway Trainer manikin. In the second study, the choice of fibrescope did not significantly affect any performance outcome (p=0.3), but there was a significant difference in the speed of intubation between the devices (p=0.02) with the i-gel the fastest intubation conduit (mean (SD) intubation time i-gel 18.5(6.8)s, intubating laryngeal mask airway = 24.1(11.2)s, classic laryngeal mask airway = 31.4(32.5)s, p=0.02). We conclude that the aScope performs well in simulated fibreoptic intubation and (if adapted for untimed use) would be a useful training tool for both simulated fibreoptic intubation and conduit-assisted intubation. The choice of manikin and conduit are also important in the success of such training. This manikin study does not predict performance in humans and a clinical study is required.

Evaluation of a single-use intubating videoscope (Ambu aScopeTM) in three airway training manikins for oral intubation, nasal intubation and intubation via three supraglottic airway devices
Anaesthesia. 2011 Apr;66(4):293-9

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Remifentanil for awake intubation

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Awake fibreopic intubation (AFOI) is indicated in a subgroup of critically ill patients in whom RSI is contraindicated due to a predicted difficult airway, and in whom time pressures do not mandate a more immediate route to the airway. Last night I intubated a patient with a swollen tongue using this technique, under remifentanil sedation. It was interesting to subsequently see that this month’s Anaesthesia contains an article on ‘remi’ for AFOI:

Remifentanil is increasingly being used as the primary agent to provide sedation during awake fibreoptic nasal intubation. In this observational study, we aimed to determine the optimal effect site concentration of remifentanil, using a target controlled infusion based on the Minto pharmacological model, to provide optimal safe intubation conditions without the use of other sedatives/premedication and/or spray-as-you-go local anaesthesia. Twenty patients with anticipated difficult airway participated in the study. Good intubating conditions were achieved in all patients with mean (SD) effect site concentration of 6.3 (3.87) ng.ml(-1) of remifentanil recorded at nasal endoscopy and 8.06 (3.52) ng.ml(-1) during tracheal intubation. No serious adverse event occurred during any of these procedures. These preliminary findings suggest that this is a feasible and safe technique for awake fibreoptic nasal intubation.

Remifentanil as single agent to facilitate awake fibreoptic intubation in the absence of premedication
Anaesthesia. 2011 May;66(5):368-72
Those of us not familiar with target controlled infusions might find a dose in micrograms per kilo more helpful. This paper from Analgesia and Anesthesia provides a useful guide, comparing relatively high and low doses of loading and maintenance doses:

Awake nasotracheal fiberoptic intubation requires an anesthetic management that provides sufficient patient comfort, adequate intubating conditions, and stable hemodynamics. Short-acting and easily titratable analgesics are excellent choices for this maneuver. In this study, our aim was to determine an appropriate dosage regimen of remifentanil for awake nasotracheal fiberoptic intubation. For that reason, we compared two different dosage regimens. Twenty-four patients were randomly assigned to receive remifentanil 0.75 micro g/kg in bolus, followed by a continuous infusion of 0.075 micro g x kg(-1) x min(-1) (Group L), or remifentanil 1.5 micro g/kg in bolus, followed by a continuous infusion of 0.15 micro g x kg(-1) x min(-1) (Group H). All patients were premedicated with midazolam 0.05 mg/kg IV and glycopyrrolate 0.2 mg IV. Both dosage regimens ensured patient comfort and sedation. Discomfort did not differ between groups. Patients in Group H were sedated more profoundly. Hemodynamic stability was maintained with both remifentanil doses. Intubating conditions were adequate in all patients and comparable between the groups. The large dosage regimen did not result in any additional benefit compared with the small dosage. For awake nasotracheal fiberoptic intubation, we therefore recommend remifentanil 0.75 micro g/kg in bolus followed by continuous infusion of 0.075 micro g x kg(-1) x min(-1), supplemented with midazolam 0.05 mg/kg

Awake nasotracheal fiberoptic intubation: patient comfort, intubating conditions, and hemodynamic stability during conscious sedation with remifentanil
Anesth Analg. 2003 Sep;97(3):904-8 (Free Full Text)

 
An alternative to bolus + maintenance is using an incremental infusion rate via an infusion pump. In a comparision with midazolam and fentanyl, remifentanil was given to 37 patients in incremental dosages (0.1-0.25-0.5 microg/kg/min) by an infusion pump according to comfort, level of sedation and respiratory depression. Nasotracheal intubation was better tolerated in the remifentanil group, who also showed better suppression of haemodynamic effects of intubation.

BACKGROUND: Awake fiberoptic intubation is the standard of care for difficult airway management. Quality and success of this technique depend on the experience of the intubating physician and the proper preparation of the patient. The aim of this study was to compare remifentanil (R) as single agent to the combination of fentanyl (F) and midazolam (M), which have been the drugs for analgesia and sedation for this procedure.
METHODS: Seventy-four adult patients requiring nasotracheal intubation were randomly assigned to one of two groups. In group I, (n=37) R was administered in incremental dosages (0.1-0.25-0.5 microg/kg/min) by an infusion pump according to comfort, level of sedation and respiratory depression. In group II, (n=37) analgesia and sedation was achieved by F 1.5 microg/kg and doses of between 1 and 10 mg M, titrated to the individual needs. Patient reactions like grimacing, movement and coughing during intubation were assessed, as well as patient recall of the procedure. Haemodynamic and respiratory parameters were continuously recorded.
RESULTS: Group I patients better tolerated nasal tube passage (P<0.001) and laryngeal tube advancement (P<0.001) than group II. Remifentanil better suppressed hemodynamic response to nasal intubation (P<0.001). No significant difference in respiratory data was recorded. In group I more recall of the procedure was observed (six vs. zero patients, P<0.05).
CONCLUSION: Remifentanil in high doses, as the single agent for patient preparation for awake fiberoptic intubation seems to improve intubating conditions, quality and reliability of the procedure. However, a higher incidence of recall is to be expected.

Evaluation of remifentanil as single drug for awake fiberoptic intubation
Acta Anaesthesiol Scand. 2002 Apr;46(4):350-4
Some authors advocate dexmedetomidine for AFOI. Remifentanil was compared with dexmedetomidine in a randomised, double-blind trial. Remi was loaded and maintained at the ‘low’ dose as described in the second paper above and was associated with a higher intubation success rate on first attempt than dexmedetomidine (76% vs 38%):

Introduction: Dexmedetomidine (DEX), a centrally acting, selective alpha-2 agonist, with analgesic and sedation properties, has been successfully used for sedation in intensive care units. Remifentanil (REM), an ultra-short acting synthetic opioid, is often used to aid awake fiberoptic intubation (AFOI). As a narcotic, REM has a potential for respiratory depression, whereas DEX does not. This study compares the use of REM and DEX as adjuncts to local anesthetic preparation of the airway for AFOI.
Methods: Thirty adult ASA I-III patients with expected difficult airways were randomized to receive REM or DEX for sedation during AFOI. Operators and assessors were blinded to the drug used. Preoperatively, all patients received 2 mg midazolam intravenously and their airways were topicalized with 4% lidocaine. Patients in the REM group received a bolus of 0.75 mcg/kg over 10 minutes followed by an infusion of 0.075 mcg/kg/min. Patients in the DEX group received a bolus of 0.4 mcg/kg over 10 minutes followed by an infusion of 0.7 mcg/kg/hr. A word and picture set was presented to each patient before any drugs were administered, after loading of either sedative, and following extubation. Heart rate, blood pressure, respiratory rate, SpO2, bispectral (BIS) index level, and Ramsay sedation level (RSS) were recorded. Recall of each 3 sets of pictures and words was assessed at 30 minute intervals for a period of 3 hours after the completion of surgery.
Results: Patient demographics were similar between the 2 groups. All patients’ airways were successfully secured by fiberoptic intubation. Seventy-six percent of REM cases were intubated on the first attempt, as compared to 38% of the DEX cases (p=0.02). Intubation attempts were greater in the DEX group even after adjusting for confounders (OR unadjusted = 5.26, 95% C.I. = 1.19, 25.72; OR adjusted = 4.84, 3.43, 6.82). The DEX group had a higher mean oxygen saturation rate than REM (1.58 higher; 95% C.I. = 0.14, 3.03; p=0.03). Although the incidence of O2 saturation < 90% was greater in the REM group, it was not significant. No apneic episodes occurred and no rescue maneuvers, such as administration of reversal drugs or positive pressure ventilation, were required in either group. There was a lower Ramsey Sedation Scale (RSS) score (lower by = 0.45, 95% C.I. = 0.1142, 0.7792; p=0.008) in the DEX group compared to the REM group. A Kaplan Meier survival analysis showed that DEX patients took longer to attain a RSS of 3 despite reaching a lower RSS score. (Logrank test = 4.00 with one degree of freedom, p=0.0455) The DEX group also had 6.99 lower (95% C.I. = 1.19, 12.79; p=0.018) BIS score compared to the REM group. Generalized estimating equations (xtgee) showed no significance in the recall results with the exception of verbal recall in the DEX group after the initial bolus. Minimal hemodynamic instability was observed in both groups.
Discussion: Both Dex and REM can be safely used as sedative agents for AFOI. Despite increased sedation and lower recall after the initial bolus, the DEX group required more attempts at intubation. Nonetheless, lower oxygen saturation was observed in the REM group.

Dexmedetomidine vs. Remifentanil for Sedation in Awake Intubations-A Randomized, Double-Blind Trial
Anesthesiology 2008; 109 A14

Acute Med, All Updates, ICU

Extracorporeal liver support in acute liver failure

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Critically ill patients may receive cardiovascular, respiratory, and renal support, but systems that perform some of the functions of the liver are less routinely used. Extracorporeal liver support can be provided by artificial systems or bioartificial systems:

  • Artificial liver support systems aim to replace the detoxification functions of the liver, based on albumin dialysis, and consist of membrane separation associated with columns or suspensions of sorbents, including charcoal and anion or cation exchange resins.
  • Bioartificial systems incorporate either human hepatoblastoma cells or porcine hepatocytes into bioreactors that are intended to perform both liver detoxification and synthetic functions. A porous barrier between the patient’s blood or plasma isolates cells from immunoglobulins and leucocytes, avoiding immune rejection. Smaller particles such as toxins, metabolites and synthesized proteins are free to cross the barrier.

Three artificial liver support system types and two bioartificial liver systems have undergone randomised controlled trials. A meta-analysis examined the effect of extracorporeal liver support on mortality

Molecular Adsorbent Recirculating System

BACKGROUND: Extracorporeal liver support (ELS) systems offer the potential to prolong survival in acute and acute-on-chronic liver failure. However, the literature has been unclear on their specific role and influence on mortality. This meta-analysis aimed to test the hypothesis that ELS improves survival in acute and acute-on-chronic liver failure.
METHODS: Clinical trials citing MeSH terms ‘liver failure’ and ‘liver, artificial’ were identified by searching MEDLINE, Embase and the Cochrane registry of randomised controlled trials (RCTs) between January 1995 and January 2010. Only RCTs comparing ELS with standard medical therapy in acute or acute-on-chronic liver failure were included. A predefined data collection pro forma was used and study quality assessed according to Consolidated Standards of Reporting Trials (CONSORT) criteria. Risk ratio was used as the effect size measure according to a random-effects model.
RESULTS: The search strategy revealed 74 clinical studies including 17 RCTs, five case-control studies and 52 cohort studies. Eight RCTs were suitable for inclusion, three addressing acute liver failure (198 participants) and five acute-on-chronic liver failure (157 participants). The mean CONSORT score was 14 (range 11-20). Overall ELS therapy significantly improved survival in acute liver failure (risk ratio 0·70; P = 0·05). The number needed to treat to prevent one death in acute liver failure was eight. No significant survival benefit was demonstrated in acute-on-chronic liver failure (risk ratio 0·87; P = 0·37).
CONCLUSION: ELS systems appear to improve survival in acute liver failure. There is, however, no evidence that they improve survival in acute-on-chronic liver failure.

Systematic review and meta-analysis of survival following extracorporeal liver support
Br J Surg. 2011 May;98(5):623-31

Acute Med, All Updates, ICU, Resus

CHEST study to evaluate starch

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No results to report here, just a heads up that the CHEST study is underway: a randomised controlled trial of 7000 patients comparing of 6% hydroxyethyl starch (130/0.4) with 0.9% sodium chloride for all fluid resuscitation needs whilst in the intensive care unit (ICU).  This is how the authors explain the rationale for the study:

Much of the evidence currently available to inform clinicians on the efficacy and safety of starch solutions for fluid resuscitation involves studies conducted using older, high molecular weight and high molar substitution starches. Meta-analyses of these studies suggest that when comparing starches to other fluids, the relative risk of mortality ranges from 1.00 (95% CI 0.80–1.25) to 1.35 (95% CI 0.94–1.95) and for kidney failure 1.50 (95% CI 1.20–1.87). There are insufficient data, however, on the newer low molecular weight, low molar substitution starches. To date, most published studies on these newer generation starches have been conducted in perioperative settings with small sample sizes and limited follow-up. They have been designed to examine surrogate outcomes and not important patient outcomes such as mortality or renal failure.

It is possible to overdo the starch

 
These are some of the same people who brought us the SAFE study on albumin and the NICE-SUGAR study on glycaemic control, so this will be one to watch. It is anticipated that recruitment will be completed by December 2011.

PURPOSE: The intravenous fluid 6% hydroxyethyl starch (130/0.4) (6% HES 130/0.4) is used widely for resuscitation but there is limited information on its efficacy and safety. A large-scale multi-centre randomised controlled trial (CHEST) in critically ill patients is currently underway comparing fluid resuscitation with 6% HES 130/0.4 to 0.9% sodium chloride on 90-day mortality and other clinically relevant outcomes including renal injury. This report describes the study protocol.
METHODS: CHEST will recruit 7,000 patients to concealed, random, parallel assignment of either 6% HES 130/0.4 or 0.9% sodium chloride for all fluid resuscitation needs whilst in the intensive care unit (ICU). The primary outcome will be all-cause mortality at 90 days post-randomisation. Secondary outcomes will include incident renal injury, other organ failures, ICU and hospital mortality, length of ICU stay, quality of life at 6 months, health economic analyses and in patients with traumatic brain injury, functional outcome. Subgroup analyses will be conducted in four predefined subgroups. All analyses will be conducted on an intention-to-treat basis.
RESULTS AND CONCLUSIONS: The study run-in phase has been completed and the main trial commenced in April 2010. CHEST should generate results that will inform and influence prescribing of this commonly used resuscitation fluid.

The Crystalloid versus Hydroxyethyl Starch Trial: protocol for a multi-centre randomised controlled trial of fluid resuscitation with 6% hydroxyethyl starch (130/0.4) compared to 0.9% sodium chloride (saline) in intensive care patients on mortality
Intensive Care Med. 2011 May;37(5):816-823

Acute Med, All Updates, ICU, Resus

Hyperbaric O2 for the sick and the well with CO poisoning

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A French study, large by hyperbaric oxygen trial standards, did not confirm that hyperbaric oxygen therapy improves recovery from pure CO poisoning. In addition, in comatose patients, repeating hyperbaric oxygen therapy resulted in worse outcomes compared to one session.

I don't care if it doesn't work - something looking like a retro-sci-fi time machine is COOL.

INTRODUCTION: Although hyperbaric oxygen therapy (HBO) is broadly used for carbon monoxide (CO) poisoning, its efficacy and practical modalities remain controversial.
OBJECTIVES: To assess HBO in patients poisoned with CO.
DESIGN: Two prospective randomized trial on two parallel groups.
SETTING: Critical Care Unit, Raymond Poincaré Hospital, Garches, France.
SUBJECTS: Three hundred eighty-five patients with acute domestic CO poisoning.
INTERVENTION: Patients with transient loss of consciousness (trial A, n = 179) were randomized to either 6 h of normobaric oxygen therapy (NBO; arm A0, n = 86) or 4 h of NBO plus one HBO session (arm A1, n = 93). Patients with initial coma (trial B, n = 206) were randomized to either 4 h of NBO plus one HBO session (arm B1, n = 101) or 4 h of NBO plus two 2 HBO sessions (arm B2, n = 105). PRIMARY ENDPOINT: Proportion of patients with complete recovery at 1 month.
RESULTS: In trial A, there was no evidence for a difference in 1-month complete recovery rates with and without HBO [58% compared to 61%; unadjusted odds ratio, 0.90 (95% CI, 0.47-1.71)]. In trial B, complete recovery rates were significantly lower with two than with one HBO session [47% compared to 68%; unadjusted odds ratio, 0.42 (CI, 0.23-0.79)].
CONCLUSION: In patients with transient loss of consciousness, there was no evidence of superiority of HBO over NBO. In comatose patients, two HBO sessions were associated with worse outcomes than one HBO session.

Hyperbaric oxygen therapy for acute domestic carbon monoxide poisoning: two randomized controlled trials
Intensive Care Med. 2011 Mar;37(3):486-92

All Updates, PHARM, Resus

Pre-hospital Airtraq use often failed

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The Airtraq seems nifty when you try it on a manikin, but until now the question of whether it would be a useful pre-hospital tool was unanswered. This Austrian study provides helpful data:

OBJECTIVES: The optical Airtraq laryngoscope (Prodol Meditec, Vizcaya, Spain) has been shown to have advantages when compared with direct laryngoscopy in difficult airway patients. Furthermore, it has been suggested that it is easy to use and handle even for inexperienced advanced life support providers. As such, we sought to assess whether the Airtraq may be a reliable alternative to conventional intubation when used in the prehospital setting.
DESIGN, SETTING, AND PATIENTS: Prospective, randomized control trial in emergency patients requiring endotracheal intubation provided by anesthesiologists or emergency physicians responding with an emergency medical service helicopter or ground unit associated with the Department of Anesthesiology, General Hospital, Wiener Neustadt, Austria.
MEASUREMENTS AND MAIN RESULTS: During the 18-month study period, 212 patients were enrolled. When the Airtraq was used as first-line airway device (n=106) vs. direct laryngoscopy (n=106), success rate was 47% vs. 99%, respectively (p<.001). Reasons for failed Airtraq intubation were related to the fiber-optic characteristic of this device (i.e., impaired sight due to blood and vomitus, n=11) or to assumed handling problems (i.e., cuff damage, tube misplacement, or inappropriate visualization of the glottis, n=24). In 54 of 56 patients where Airtraq intubation failed, direct laryngoscopy was successful on the first attempt; in the remaining two and in one additional case of failed direct laryngoscopy, the airway was finally secured employing the Fastrach laryngeal mask. There was no correlation between success rates and body mass index, age, indication for airway management, emergency medical service unit, or experience of the physicians. CONCLUSIONS: Based on these results, the use of the Airtraq laryngoscope as a primary airway device cannot be recommended in the prehospital setting without significant clinical experience obtained in the operation room. We conclude that the clinical learning process of the Airtraq laryngoscope is much longer than reported in the anesthesia literature.

Use of the Airtraq laryngoscope for emergency intubation in the prehospital setting: A randomized control trial
Crit Care Med. 2011 Mar;39(3):489-93

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

Salt or sugar on the brain

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A meta-analysis suggests hypertonic saline may be more effective at lowering intracranial pressure than mannitol. An accompanying editorial cleverly entitled ‘Salt or sugar on the brain: Does it matter except for taste?’ suggests one reason hypertonic saline (HTS) has not replaced mannitol in clinical practice is that too many different regimens of HTS, in terms of concentration, dose, bolus vs. continuous infusions, and plus or minus supplementation of colloids, have been utilised. Because only 112 patients with 184 episodes of increased ICP were treated with each medication in this meta-analysis, the editorialist agrees with the authors in suggesting a larger randomised study is needed.

OBJECTIVES: Randomized trials have suggested that hypertonic saline solutions may be superior to mannitol for the treatment of elevated intracranial pressure, but their impact on clinical practice has been limited, partly by their small size. We therefore combined their findings in a meta-analysis.
DATA SOURCES: We searched for relevant studies in MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials (CENTRAL), Scopus, and ISI Web of Knowledge.
STUDY SELECTION: Randomized trials were included if they directly compared equiosmolar doses of hypertonic sodium solutions to mannitol for the treatment of elevated intracranial pressure in human subjects undergoing quantitative intracranial pressure measurement.
DATA EXTRACTION: Two investigators independently reviewed potentially eligible trials and extracted data using a preformed data collection sheet. Disagreements were resolved by consensus or by a third investigator if needed. We collected data on patient demographics, type of intracranial pathology, baseline intracranial pressure, osms per treatment dose, quantitative change in intracranial pressure, and prespecified adverse events. Our primary outcome was the proportion of successfully treated episodes of elevated intracranial pressure.
DATA SYNTHESIS: Five trials comprising 112 patients with 184 episodes of elevated intracranial pressure met our inclusion criteria. In random-effects models, the relative risk of intracranial pressure control was 1.16 (95% confidence interval, 1.00-1.33), and the difference in mean intracranial pressure reduction was 2.0 mm Hg (95% confidence interval, -1.6 to 5.7), with both favoring hypertonic saline over mannitol. A mild degree of heterogeneity was present among the included trials. There were no significant adverse events reported.
CONCLUSIONS: We found that hypertonic saline is more effective than mannitol for the treatment of elevated intracranial pressure. Our meta-analysis is limited by the small number and size of eligible trials, but our findings suggest that hypertonic saline may be superior to the current standard of care and argue for a large, multicenter, randomized trial to definitively establish the first-line medical therapy for intracranial hypertension.

Hypertonic saline versus mannitol for the treatment of elevated intracranial pressure: A meta-analysis of randomized clinical trials
Crit Care Med. 2011 Mar;39(3):554-9

Acute Med, All Updates, ICU, Kids, PHARM, Resus

Cardiac arrest drugs and pupils

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Although not predictive immediately post-cardiac arrest in the emergency department, dilated unreactive pupils two or three days later on the ICU may indicate a hopeless prognosis. We know from our experience with adrenaline (epinephrine) infusions that this drug does not prevent pupils from reacting to light, but what about atropine?

A letter by Dr Sophie MacDougall-Davis in Resuscitation describes a 66 year old male patient admitted to the ICU after an intraoperative PEA arrest during which he received 3 mg intravenous atropine. Post arrest and post anaesthesia he was awake with no neurological deficit, but eight hours after the cardiac arrest his pupils remained fixed and dilated, and were dilated with only a very slight reaction the next morning and remained sluggish at forty-eight hours, normalising at seventy-two hours. A possible reason for its prolonged action may be uptake of atropine from the plasma into the aqueous humor of the eye, followed by its slow release.
Dr MacDougall-Davis cautions:

When assessing pupils in comatose cardiac arrest survivors, the potential for atropine to have a prolonged effect on pupil size and reactivity should be considered.

Atropine, fixed dilated pupils and prognostication following cardiac arrest
Resuscitation. 2011 Feb;82(2):232

All Updates, ICU, Resus

Video laryngoscope successes and failures

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With a difficult airway, video laryngoscopes can get you out of a hole – or rather into one. However they’re not guaranteed for all eventualities; a large study of Glidescope use showed:

  • Primary intubation with the Glidescope was successful in 98% of 1,755 cases and rescued failed direct laryngoscopy in 94% of 239 cases.
  • Altered neck anatomy with presence of a surgical scar, radiation changes, or mass was the strongest predictor of Glidescope failure.

 

 

INTRODUCTION: The Glidescope video laryngoscope has been shown to be a useful tool to improve laryngeal view. However, its role in the daily routine of airway management remains poorly characterized.
METHODS: This investigation evaluated the use of the Glidescope at two academic medical centers. Electronic records from 71,570 intubations were reviewed, and 2,004 cases were identified where the Glidescope was used for airway management. We analyzed the success rate of Glidescope intubation in various intubation scenarios. In addition, the incidence and character of complications associated with Glidescope use were recorded. Predictors of Glidescope intubation failure were determined using a logistic regression analysis.
RESULTS: Overall success for Glidescope intubation was 97% (1,944 of 2,004). As a primary technique, success was 98% (1,712 of 1,755), whereas success in patients with predictors of difficult direct laryngoscopy was 96% (1,377 of 1,428). Success for Glidescope intubation after failed direct laryngoscopy was 94% (224 of 239). Complications were noticed in 1% (21 of 2,004) of patients and mostly involved minor soft tissue injuries, but major complications, such as dental, pharyngeal, tracheal, or laryngeal injury, occurred in 0.3% (6 of 2,004) of patients. The strongest predictor of Glidescope failure was altered neck anatomy with presence of a surgical scar, radiation changes, or mass.
CONCLUSION: These data demonstrate a high success rate of Glidescope intubation in both primary airway management and rescue-failed direct laryngoscopy. However, Glidescope intubation is not always successful and certain predictors of failure can be identified. Providers should maintain their competency with alternate methods of intubation, especially for patients with neck pathology.

Routine Clinical Practice Effectiveness of the Glidescope in Difficult Airway Management
Anesthesiology. 2011 Jan;114(1):34-41