Category Archives: ICU

Stuff relevant to patients on ICU

Acute Med, All Updates, ICU, Resus

Dobutamine for severe heart failure – more harm than good?

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A systematic review and meta-analysis of randomised controlled trials showed dobutamine is not associated with improved mortality in heart failure patients and in the case of severe heart failure there is some suggestion of increased mortality, although this did not reach statistical significance.
The authors do point out that the quality of the reports of the trials reviewed was suboptimal. However, they state:
It should be noted that the results of this study are in accord with large observational studies that have also suggested harm associated with use of dobutamine in patients with severe heart failure. Taken together, this evidence should cause clinicians to reconsider their use of dobutamine in patients with heart failure, particularly those most at risk of the adverse effects, those with underlying ischaemic heart disease.

PURPOSE: Dobutamine is recommended for patients with severe heart failure; however uncertainty exists as to its effect on mortality. This study aims to critically review the literature to evaluate whether dobutamine, compared with placebo or standard care, is associated with lower mortality and a range of secondary outcomes, in patients with severe heart failure.
METHODS: A systematic review and meta-analysis of randomised controlled trials was performed. PubMed, EMBASE, the Cochrane Central Trials Registry, the metaRegister of Controlled Trials and bibliographies of retrieved articles were searched. Randomised trials comparing dobutamine with placebo or standard care, in human, adult patients with severe heart failure, were included if they reported at least one outcome of interest. Data regarding trial validity, methodological processes and clinical outcomes were extracted, and a meta-analysis was performed.
RESULTS: Fourteen studies, with 673 participants, met the inclusion criteria and were included; 13 studies reported mortality. There was minimal heterogeneity (I (2) = 4.5%). The estimate of the odds ratio for mortality for patients with severe heart failure treated with dobutamine compared with standard care or placebo was 1.47 (95% confidence interval 0.98-2.21, p = 0.06).
CONCLUSIONS: This meta-analysis showed that dobutamine is not associated with improved mortality in patients with heart failure, and there is a suggestion of increased mortality associated with its use, although this did not reach the conventional level of statistical significance. Further research to define the role of dobutamine in treatment of severe heart failure should be a priority.

Dobutamine for patients with severe heart failure- a systematic review and meta-analysis of randomised controlled trials
Intensive Care Med. 2012 Mar;38(3):359-67

All Updates, Guidelines, ICU, Resus

Colloid volume therapy for critically ill patients

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The European Society of Intensive Care Medicine has produced a consensus statement on colloid volume therapy for critically ill patients, published in this month’s Intensive Care Medicine.
Curiously, the full text document is not yet availablle on ESICM’s website, but I found this presentation summarising the work by one the authors (Richard Beale):


PURPOSE: Colloids are administered to more patients than crystalloids, although recent evidence suggests that colloids may possibly be harmful in some patients. The European Society of Intensive Care Medicine therefore assembled a task force to compile consensus recommendations based on the current best evidence for the safety and efficacy of the currently most frequently used colloids-hydroxyethyl starches (HES), gelatins and human albumin.

METHODS: Meta-analyses, systematic reviews and clinical studies of colloid use were evaluated for the treatment of volume depletion in mixed intensive care unit (ICU), cardiac surgery, head injury, sepsis and organ donor patients. Clinical endpoints included mortality, kidney function and bleeding. The relevance of concentration and dosage was also assessed. Publications from 1960 until May 2011 were included. The quality of available evidence and strength of recommendations were based on the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach.

RECOMMENDATIONS AND CONCLUSIONS: We recommend not to use HES with molecular weight ≥200 kDa and/or degree of substitution >0.4 in patients with severe sepsis or risk of acute kidney injury and suggest not to use 6% HES 130/0.4 or gelatin in these populations. We recommend not to use colloids in patients with head injury and not to administer gelatins and HES in organ donors. We suggest not to use hyperoncotic solutions for fluid resuscitation. We conclude and recommend that any new colloid should be introduced into clinical practice only after its patient-important safety parameters are established.

Consensus statement of the ESICM task force on colloid volume therapy in critically ill patients
Intensive Care Med. 2012 Mar;38(3):368-83
Update September 2012:
An RCT showed patients with severe sepsis assigned to fluid resuscitation with HES 130/0.42 had an increased risk of death at day 90 and were more likely to require renal-replacement therapy, as compared with those receiving Ringer’s acetate. Read more about the trial here
Hydroxyethyl Starch 130/0.42 versus Ringer’s Acetate in Severe Sepsis
N Engl J Med. 2012 Jul 12;367(2):124-34
Australian intensivist John Myburgh gives a great summary of Fluid Therapy in critical care here

All Updates, Guidelines, ICU, Kids, Resus

Severe Traumatic Brain Injury in Children

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The Brain Trauma Foundation has released updated guidelines on traumatic brain injury in children.
Most of the recommendations are Grade C and therefore based on limited evidence.

Indications for ICP monitoring
Use of intracranial pressure (ICP) monitoring may be considered in infants and children with severe traumatic brain injury (TBI) (Grade C).
Four lines of evidence support the use of ICP monitoring in children with severe TBI:

  • a frequently reported high incidence of intracranial hypertension in children with severe TBI
  • a widely reported association of intracranial hypertension and poor neurologic outcome
  • the concordance of protocol-based intracranial hypertension therapy and best-reported clinical outcomes
  • and improved outcomes associated with successful ICP-lowering therapies.

Threshold for treatment of intracranial hypertension
Treatment of intracranial pressure (ICP) may be considered at a threshold of 20 mm Hg (Grade C).
Sustained elevations in ICP (>20 mm Hg) are associated with poor outcome in children after severe TBI.
Normal values of blood pressure and ICP are age-dependent (lower at younger ages), so it is anticipated that the optimal ICP treatment threshold may be age-dependent.
Cerebral perfusion pressure thresholds
A CPP threshold 40–50 mm Hg may be considered. There may be age-specific thresholds with infants at the lower end and adolescents at the upper end of this range (Grade C).
Survivors of severe pediatric TBI undergoing ICP monitoring consistently have higher CPP values vs. nonsurvivors, but no study demonstrates that active maintenance of CPP above any target threshold in pediatric TBI reduces mortality or morbidity.
CPP should be determined in a standard fashion with ICP zeroed to the tragus (as an indicator of the foramen of Monro and midventricular level) and MAP zeroed to the right atrium with the head of the bed elevated 30°.
Advanced neuromonitoring
If brain oxygenation monitoring is used, maintenance of partial pressure of brain tissue oxygen (PbtO2) >10 mm Hg may be considered.
Neuroimaging
In the absence of neurologic deterioration or increasing intracranial pressure (ICP), obtaining a routine repeat computed tomography (CT) scan >24 hrs after the admission and initial follow-up study may not be indicated for decisions about neurosurgical intervention (Grade C).
Hyperosmolar therapy
Hypertonic saline should be considered for the treatment of severe pediatric traumatic brain injury (TBI) associated with intracranial hypertension. Effective doses for acute use range between 6.5 and 10 mL/kg (of 3%) (Grade B).
Hypertonic saline should be considered for the treatment of severe pediatric TBI associated with intracranial hypertension. Effective doses as a continuous infusion of 3% saline range between 0.1 and 1.0 mL/kg of body weight per hour administered on a sliding scale. The minimum dose needed to maintain intracranial pressure (ICP)
Temperature control
Moderate hypothermia (32–33°C) beginning early after severe traumatic brain injury (TBI) for only 24 hrs’ duration should be avoided.
Moderate hypothermia (32–33°C) be- ginning within 8 hrs after severe TBI for up to 48 hrs’ duration should be considered to reduce intracranial hypertension.
If hypothermia is induced for any indication, rewarming at a rate of >0.5°C/hr should be avoided (Grade B).
Moderate hypothermia (32–33°C) be- ginning early after severe TBI for 48 hrs, duration may be considered (Grade C).
Note: after completion of these guidelines, the committee became aware that the Cool Kids trial of hypothermia in pediatric TBI was stopped because of futility. The implications of this development on the recommendations in this section may need to be considered by the treating physician when details of the study are published.
Cerebrospinal fluid drainage
Cerebrospinal fluid (CSF) drainage through an external ventricular drain may be considered in the management of increased intracranial pressure (ICP) in children with severe traumatic brain injury (TBI).
The addition of a lumbar drain may be considered in the case of refractory intracranial hypertension with a functioning external ventricular drain, open basal cis- terns, and no evidence of a mass lesion or shift on imaging studies (Grade C).
Barbiturates
High-dose barbiturate therapy may be considered in hemodynamically stable patients with refractory intracranial hypertension despite maximal medical and surgical management.
When high-dose barbiturate therapy is used to treat refractory intracranial hy- pertension, continuous arterial blood pressure monitoring and cardiovascular support to maintain adequate cerebral perfusion pressure are required (Grade C).
Decompressive craniectomy for the treatment of intracranial hypertension
Decompressive craniectomy (DC) with duraplasty, leaving the bone flap out, may be considered for pediatric patients with traumatic brain injury (TBI) who are showing early signs of neurologic deterioration or herniation or are developing intracranial hypertension refractory to medical management during the early stages of their treatment (Grade C).
Hyperventilation
Avoidance of prophylactic severe hyperventilation to a PaCO2 If hyperventilation is used in the management of refractory intracranial hypertension, advanced neuromonitoring for evaluation of cerebral ischemia may be considered (Grade C).
Corticosteroids
The use of corticosteroids is not recommended to improve outcome or reduce intracranial pressure (ICP) for children with severe traumatic brain injury (TBI) (Grade B).
Analgesics, sedatives, and neuromuscular blockade
Etomidate may be considered to control severe intracranial hypertension; however, the risks resulting from adrenal suppression must be considered.
Thiopental may be considered to control intracranial hypertension.
In the absence of outcome data, the specific indications, choice and dosing of analgesics, sedatives, and neuromuscular-blocking agents used in the management of infants and children with severe traumatic brain injury (TBI) should be left to the treating physician.
*As stated by the Food and Drug Administration, continuous infusion of propofol for either sedation or the management of refractory intracranial hypertension in infants and children with severe TBI is not recommended (Grade C).
The availability of other sedatives and analgesics that do not suppress adrenal function, small sample size and single-dose administration in the study discussed previously, and limited safety profile in pediatric TBI limit the ability to endorse the general use of etomidate as a sedative other than as an option for single-dose administration in the setting of raised ICP.
Glucose and nutrition
The evidence does not support the use of an immune-modulating diet for the treatment of severe traumatic brain injury (TBI) to improve outcome (Grade B).
In the absence of outcome data, the specific approach to glycemic control in the management of infants and children with severe TBI should be left to the treating physician (Grade C).
Antiseizure prophylaxis
Prophylactic treatment with phenytoin may be considered to reduce the incidence of early posttraumatic seizures (PTS) in pediatric patients with severe traumatic brain injury (TBI) (Grade C).
The incidence of early PTS in pediatric patients with TBI is approximately 10% given the limitations of the available data. Based on a single class III study (4), prophylactic anticonvulsant therapy with phenytoin may be considered to reduce the incidence of early posttraumatic seizures in pediatric patients with severe TBI. Concomitant monitoring of drug levels is appropriate given the potential alterations in drug metabolism described in the context of TBI. Stronger class II evidence is available supporting the use of prophylactic anticonvulsant treatment to reduce the risk of early PTS in adults. There are no compelling data in the pediatric TBI literature to show that such treatment reduces the long-term risk of PTS or improves long-term neurologic outcome.
Guidelines for the Acute Medical Management of Severe Traumatic Brain Injury in Infants, Children, and Adolescents-Second Edition
Pediatr Crit Care Med 2012 Vol. 13, No. 1 (Suppl.)
Read online
Download PDF (617k)
Other Brain Trauma Foundation Guidelines

Acute Med, All Updates, ICU, Resus, Ultrasound

Posterior pericardiocentesis

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Dr Emanuele Catena and colleagues report a case of an adult male who presented 7 days post cardiac surgery with simultaneous pleural and pericardial effucions causing dyspnoea, tachycardia and hypotension.

Old skool pericardiocentesis

His pericardial effusion was posterior which usually requires surgical drainage, but the adjacent left pleural effusion was associated with pulmonary atelectasis and displacement of the lung, allowing them to insert a needle using sonographic guidance first into the pleural space then the pericardial space.
They inserted through the fourth intercostal space 4 cm medially to the left posterior axillary line (with the patient positioned in the semireclining position). They used agitated saline bubbles to confirm first the pleural then the pericardial location of the needle tip. A 30-cm-long catheter was introduced into the posterior pericardium using the Seldinger technique, and serous-haemorrhagic fluid was drained. The catheter was then retracted allowing drainage of the pleural effusion.
The procedure resulted in haemodynamic and respiratory improvement.
The authors summarise:


This case reports the technique of a “back pericardiocentesis” performed under echographic guidance as a valid alternative to surgery in the peculiar situation characterized by the simultaneous presence of a large left pleural effusion. In the presence of a large left pleural effusion, pulmonary atelectasis and displacement of air-filled pulmonary tissue allows ultrasound transmission from a patient’s back to the heart through a liquid interface and needle insertion “from back” to reach the pericardial space.

 
Pericardiocentesis From Back Under Echographic Guidance An Approach for Posterior Pericardial Effusions
Circulation. 2011 Dec 13;124(24):e835-6

All Updates, ICU, Resus

Airway lessons relearned

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A UK study examined all out-of-operating room intubations over a one month period in nine hospitals1.
Patients whose indication for tracheal intubation was cardiac arrest and who were intubated without the use of drugs were excluded from analysis, as were neonatal intubations.
Disappointing – but not surprising – findings were the lack of universally applied capnography and the use of propofol as the most commonly used induction agent. However more senior intubators were less likely to use propofol than more junior ones (who used it in 93% of intubations!), and the seniors were also more likely to use non-depolarising neuromuscular blocking drugs (NMBDs) than juniors.
The authors report that in seven (4%) patients, pre-oxygenation “was felt to be impossible“. I find it hard to imagine this situation unless RSI is being done on combative patients without prior sedation, which if this is the case makes me shudder.
The authors express their understandable concern over the absence of an alternative airway such as a laryngeal mask in 12% of cases.
Although the adverse event rate seems high, they point out that they used the term ‘adverse events’ rather than ‘complications’ as the events may not be directly attributable to the intubation. In other words, some patients may have been hypoxaemic or hypotensive to start with due to their underlying clinical problem.
I find this study interesting because the results are similar to those reported in a study I and my colleagues conducted a decade ago2, in which ICU intubations were shown to be more hazardous that ED intubations. This can be explained by the higher proportion of patients on ICU with shock and/or respiratory failure. On the other hand, ED patients more commonly required intubation for neurological presentations, with relatively stable cardiorespiratory physiology.
Take a look at the breakdown of cases in the recent study:

and compare this with our findings:

…this is why I have to argue when I hear it occasionally stated that ‘all ED airways are difficult airways’ – some are actually easy, in patients with long stable apnoea times who make great teaching cases.
The authors “speculate that the low rate of hypoxaemia and airway complications may be related to the high proportion of intubations undertaken by those with anaesthesia as a base speciality, and to the almost universal use of NMBDs.” They do not provide strong data to support the first half of their statement. The supplementary data available online indeed show that the majority of intubators were anaesthesia-based, but how their adverse event rates compare with those of the emergency physicians and paediatricians who also undertook intubations is not available.
I don’t want to detract from the important message Dr Bowles and colleagues are conveying: that the lessons from the 4th National Audit Project on major complications of airway management in the UK still need to be applied.
This paper is one aspect of the potentially life-saving work done by this team, which includes the intubation checklist they created.


BACKGROUND: Tracheal intubation is commonly performed outside the operating theatre and is associated with higher risk than intubation in theatre. Recent guidelines and publications including the 4th National Audit Project of the Royal College of Anaesthetists have sought to improve the safety of out-of-theatre intubations.

METHODS: We performed a prospective observational study examining all tracheal intubations occurring outside the operating theatre in nine hospitals over a 1 month period. Data were collected on speciality and grade of intubator, presence of essential safety equipment and monitoring, and adverse events.

RESULTS: One hundred and sixty-four out-of-theatre intubations were identified (excluding those where intubation occurred as part of the management of cardiac arrest). The most common indication for intubation was respiratory failure [74 cases (45%)]. Doctors with at least 6 month’s experience in anaesthesia performed 136 intubations (83%); consultants were present for 68 cases (41%), and overall a second intubator was present for 94 procedures (57%). Propofol was the most common induction agent [124 cases (76%)] and 157 patients (96%) received neuromuscular blocking agents. An airway rescue device was available in 139 cases (87%). Capnography was not used in 52 cases (32%). Sixty-four patients suffered at least one adverse event (39%) around the time of tracheal intubation.

CONCLUSIONS: Out-of-theatre intubation frequently occurs in the absence of essential safety equipment, despite the existing guidelines. The associated adverse event rate is high.

1. Out-of-theatre tracheal intubation: prospective multicentre study of clinical practice and adverse events
Br J Anaesth. 2011 Nov;107(5):687-92


BACKGROUND: Emergency rapid sequence intubation (RSI) performed outside the operating room on emergency patients is the cornerstone of emergency airway management. Complication rates are unknown for this procedure in the United Kingdom and the factors contributing to immediate complications have not been identified.

AIMS: To quantify the immediate complications of RSI and to assess the contribution made by environmental, patient, and physician factors to overall complication rates.

METHODS: Prospective observational study of 208 consecutive adult and paediatric patients undergoing RSI over a six month period.

RESULTS: Patients were successfully intubated by RSI in all cases. There were no deaths during the procedure and no patient required a surgical airway. Patient diagnostic groups requiring RSI are described. Immediate complications were hypoxaemia 19.2%, hypotension 17.8%, and arrhythmia 3.4%. Hypoxaemia was more common in patients with pre-existing respiratory or cardiovascular conditions than in patients with other diagnoses (p<0.01). Emergency department intubations were associated with a significantly lower complication rate than other locations (16.9%; p = 0.004). This can be explained by the difference in diagnostic case mix. Intubating teams comprised anaesthetists, non-anaesthetists, or both. There were no significant differences in complication rates between these groups.
CONCLUSIONS: RSI has a significant immediate complication rate, although the clinical significance of transient events is unknown. The likelihood of immediate complications depends on the patient’s underlying condition, and relevant diagnoses should be emphasised in airway management training. Complication rates are comparable between anaesthetists and non-anaesthetists. The significantly lower complication rates in emergency department RSI can be explained by a larger proportion of patients with comparatively stable cardiorespiratory function.

2. The who, where, and what of rapid sequence intubation: prospective observational study of emergency RSI outside the operating theatre
Emerg Med J. 2004 May;21(3):296-301 Free Full Text

Acute Med, All Updates, ICU, Resus

β-2 agonists could worsen ARDS outcome

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Image: Wikipedia. I really fancy a curry now.

A previous study (BALTI-1) suggested β-2 agonists may help in ARDS by reducing extravascular lung water. A randomised trial in the UK aimed to recruit 1334 patients to compare intravenous salbutamol infused for seven days with placebo (0.9% saline). However the Data Monitoring and Ethics Committee recommended that the study stop after the second interim analysis of 273 patients because of a significant increase in mortality. It is unclear why salbutamol is harmful, and could be due to lung, cardiovascular, or other metabolic effects, such as activation of the renin-angiotensin aldosterone system affecting fluid balance.


BACKGROUND:In a previous randomised controlled phase 2 trial, intravenous infusion of salbutamol for up to 7 days in patients with acute respiratory distress syndrome (ARDS) reduced extravascular lung water and plateau airway pressure. We assessed the effects of this intervention on mortality in patients with ARDS.

METHODS:We did a multicentre, placebo-controlled, parallel-group, randomised trial at 46 UK intensive-care units between December, 2006, and March, 2010. Intubated and mechanically ventilated patients (aged ≥16 years) within 72 h of ARDS onset were randomly assigned to receive either salbutamol (15 μg/kg ideal bodyweight per h) or placebo for up to 7 days. Randomisation was done by a central telephone or web-based randomisation service with minimisation by centre, pressure of arterial oxygen to fractional inspired oxygen concentration (PaO2/FiO2) ratio, and age. All participants, caregivers, and investigators were masked to group allocation. The primary outcome was death within 28 days of randomisation. Analysis was by intention-to-treat. This trial is registered, ISRCTN38366450 and EudraCT number 2006-002647-86.

FINDINGS:We randomly assigned 162 patients to the salbutamol group and 164 to the placebo group. One patient in each group withdrew consent. Recruitment was stopped after the second interim analysis because of safety concerns. Salbutamol increased 28-day mortality (55 [34%] of 161 patients died in the salbutamol group vs 38 (23%) of 163 in the placebo group; risk ratio [RR] 1·47, 95% CI 1·03-2·08).

INTERPRETATION:Treatment with intravenous salbutamol early in the course of ARDS was poorly tolerated. Treatment is unlikely to be beneficial, and could worsen outcomes. Routine use of β-2 agonist treatment in ventilated patients with this disorder cannot be recommended.

FUNDING:UK Medical Research Council, UK Department of Health, UK Intensive Care Foundation.

Effect of intravenous β-2 agonist treatment on clinical outcomes in acute respiratory distress syndrome (BALTI-2): a multicentre, randomised controlled trial
Lancet 379(9812, 21–27 January 2012, Pages 229–235

All Updates, ICU, PHARM, Resus, Trauma

FIRST: Fluids in Resuscitation of Severe Trauma

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This is the first randomized, controlled, double-blind study comparing crystalloids with isotonic colloids in trauma. 0.9% saline was compared with hydroxyethyl starch, HES 130/0.4, as a resuscitation fluid in pre-defined subgroups of penetrating and blunt trauma. While a primary outcome measure of gastrointestinal recovery might not seem an obvious choice to some of us, previous research has indicated this to be an issue with crystalloid and the authors clearly defined this as a predefined outcome when registering the trial here.

I don't have any pictures of colloids. Here's where I work.

Colloids tend to require smaller volumes than crystalloid to achieve the same degree of plasma expansion. An interesting finding in this study is that the volume of saline administered was 1.5 times that of hydroxyethyl starch – a very similar ratio to that seen in the SAFE study which compared saline with 4% albumin in intensive care patients.
The authors assert: “..the better lactate clearance in the P-HES group indicated superior tissue resuscitation with the colloid.” There are a number of reasons why this might be a bit of stretch, including the use of epinephrine in some patients which is known to be a cause of hyperlactataemia.
This is a small study whose conclusions should be treated with caution, but which provides an important contribution to the pool of fluid resuscitation literature. If you have full text access to the British Journal of Anaesthesia, the letters pages provide excellent critiques and responses regarding potential flaws in this paper. Nevertheless, it’s one to know about – I’m sure the FIRST trial is going to be quoted for some time to come, including, I suspect, by the manufacturers of certain colloids.


Background The role of fluids in trauma resuscitation is controversial. We compared resuscitation with 0.9% saline vs hydroxyethyl starch, HES 130/0.4, in severe trauma with respect to resuscitation, fluid volume, gastrointestinal recovery, renal function, and blood product requirements.

Methods Randomized, controlled, double-blind study of severely injured patients requiring>3 litres of fluid resuscitation. Blunt and penetrating trauma were randomized separately. Patients were followed up for 30 days.

Results A total of 115 patients were randomized; of which, 109 were studied. For patients with penetrating trauma (n=67), the mean (sd) fluid requirements were 5.1 (2.7) litres in the HES group and 7.4 (4.3) litres in the saline group (P<0.001). In blunt trauma (n=42), there was no difference in study fluid requirements, but the HES group required significantly more blood products [packed red blood cell volumes 2943 (1628) vs 1473 (1071) ml, P=0.005] and was more severely injured than the saline group (median injury severity score 29.5 vs 18; P=0.01). Haemodynamic data were similar, but, in the penetrating group, plasma lactate concentrations were lower over the first 4 h (P=0.029) and on day 1 with HES than with saline [2.1 (1.4) vs 3.2 (2.2) mmol litre−1; P=0.017]. There was no difference between any groups in time to recovery of bowel function or mortality. In penetrating trauma, renal injury occurred more frequently in the saline group than the HES group (16% vs 0%; P=0.018). In penetrating trauma, maximum sequential organ function scores were lower with HES than with saline (median 2.4 vs 4.5, P=0.012). No differences were seen in safety measures in the blunt trauma patients.
Conclusions In penetrating trauma, HES provided significantly better lactate clearance and less renal injury than saline. No firm conclusions could be drawn for blunt trauma.

Resuscitation with hydroxyethyl starch improves renal function and lactate clearance in penetrating trauma in a randomized controlled study: the FIRST trial (Fluids in Resuscitation of Severe Trauma)

Br J Anaesth. 2011 Nov;107(5):693-702

All Updates, ICU, Resus

Adjacent haemofiltration catheters can remove CVC drugs

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An important consideration when siting your lines in your critical care patients who require renal replacement therapy…


Dual-lumen haemodiafiltration catheters enable continuous renal replacement therapy in the critically ill and are often co-located with central venous catheters used to infuse drugs. The extent to which infusions are immediately aspirated by an adjacent haemodiafiltration catheter remains unknown. A bench model was constructed to evaluate this effect. A central venous catheter and a haemodiafiltration catheter were inserted into a simulated central vein and flow generated using centrifugal pumps within the simulated vein and haemodiafiltration circuit. Ink was used as a visual tracer and creatinine solution as a quantifiable tracer. Tracers were completely aspirated by the haemodiafiltration catheter unless the infusion was at least 1 cm downstream to the arterial port. No tracer was aspirated from catheters infusing at least 2 cm downstream. Orientation of side ports did not affect tracer elimination. Co-location of central venous and haemodiafiltration catheters may lead to complete aspiration of infusions into the haemodiafilter with resultant drug under-dosing.

Adjacent central venous catheters can result in immediate aspiration of infused drugs during renal replacement therapy
Anaesthesia. 2012 Feb;67(2):115-121

Acute Med, All Updates, ICU, Resus

Vasopressin – what it does and doesn't do

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The current Surviving Sepsis campaign guidelines recommend that vasopressin should not be administered as the initial vasopressor in septic shock, and that vasopressin at constant dosage of 0.03 units/min may be added to norepinephrine with anticipation of an effect equivalent to that of norepinephrine alone. European intensivists conducted a systematic review to determine vasopressin’s risks and benefits in vasodilatory shock. There was no demonstrated survival benefit but its use is associated with a significant reduction in norepinephrine requirement.
Interestingly, the authors point out: ‘Low-dose vasopressin may help to restore blood pressure in patients with hypotension refractory to catecholamines, and may favor pulmonary vasodilation and increase glomerular filtration rate and plasma cortisol levels’.
My take home: consider its use if an apparent vasodilatory shock state is refractory to catecholamines, but don’t stress if you don’t have access to it (or it will complicate practical aspects of organising resuscitation and transfer), since there’s still no clear evidence for outcome benefit.


OBJECTIVE:
To examine the benefits and risks of vasopressin or its analog terlipressin for patients with vasodilatory shock.

DATA SOURCE:
We searched the CENTRAL, MEDLINE, EMBASE, and LILACS databases (up to March 2011) as well as reference lists of articles and proceedings of major meetings; we also contacted trial authors. We considered randomized and quasirandomized trials of vasopressin or terlipressin versus placebo or supportive treatment in adult and pediatric patients with vasodilatory shock. The primary outcome for this review was short-term all-cause mortality.

STUDY SELECTION:
We identified 10 randomized trials (1,134 patients). Six studies were considered for the main analysis on mortality in adults.

DATA EXTRACTION AND SYNTHESIS:
The crude short-term mortality was 206 of 512 (40.2%) in vasopressin/terlipressin-treated patients and 198 of 461 (42.9%) in controls [six trials, risk ratio (RR) = 0.91; 95% confidence interval (CI) 0.79-1.05; P = 0.21; I (2) = 0%]. There were 49 of 463 (10.6%) patients with serious adverse events in the vasopressin/terlipressin arm and 51 of 431 (11.8%) in the control arm (four trials, RR = 0.90; 95% CI 0.49-1.67; P = 0.75; I (2) = 26%). Metaregression analysis showed negative correlation between vasopressin dose and norepinephrine dose (P = 0.03).

CONCLUSIONS:
Overall, use of vasopressin or terlipressin did not produce any survival benefit in the short term in patients with vasodilatory shock. Physicians may value the sparing effects of vasopressin/terlipressin on norepinephrine requirement given its apparent safe profile.

Vasopressin for treatment of vasodilatory shock: an ESICM systematic review and meta-analysis
Intensive Care Med. 2012 Jan;38(1):9-19

All Updates, ICU, Kids, PHARM, Resus

A big brain saves a little one

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Something I’ve been teaching for years – but never actually done – has been described in a case report from Oman.
A 2 year old child suffered a respiratory arrest due to an inhaled foreign body, which led to a bradyasystolic cardiac arrest. She was intubated by the resuscitation team who could not achieve any ventilation through the tube. The tube was removed and reinserted by an ‘expert’ (there is no mention of capnometry, for what it’s worth) and the same problem persisted.
The life-saving manouevre was to insert the tracheal tube further down into the right main bronchus and then withdraw to the trachea. This forced the obstructing object distally so that one-lung ventilation was then possible, resulting in return of spontaneous circulation and oxygen saturations in the mid-80’s. The object – a broken piece of plastic – was removed bronchoscopically and happily the child made an uneventful recovery.
Is this technique in your list of life-saving tricks? Hopefully, it is now.
A child is alive because a doctor was able to ‘think outside the guidelines’ in an incredibly high pressure situation. Rigid adherence to ACLS procedures here would have been futile. The guidelines save lives, but a few more can be saved when care can be individualised to the clinical situation by a thinking clinician.
Well done Dr Mishra and colleagues.

Sudden near-fatal tracheal aspiration of an undiagnosed nasal foreign body in a small child
Emerg Med Australas. 2011 Dec;23(6):776-8
[And here’s something else to consider if you have no airway equipment with you and your basic choking algorithm isn’t working]