Blog Index
The journal that this archive was targeting has been deleted. Please update your configuration.
Navigation

Evidence reigns supreme.

Here are some articles which may challenge the way we think and practise...albeit one small step at a time. 

Monday
May182015

Fluid Choice Matters

During a large-volume sepsis resuscitation, your choice of fluids could mean the difference between life, death and dialysis 

Early appropriate antibiotics and fluid resuscitation is the standard of care in the initial management of sepsis in the ED.

Recent literature has studied goal MAP requirements [2], endpoints such as lactate clearance [3], and how best to evaluate volume responsiveness (IVC measurement [4], passive leg raise [5], and carotid velocity time integrals [6]). 

Other studies now demonstrate that the type of fluid you choose also matters. Crystalloids have now been shown to be superior to colloids and in severely unwell patients outcomes and rate of adverse events are improved with the use of balanced solutions such as Lactated Ringers (LR)  (also known as Hartmanns solution).

Patients often receive 3-4 litres of crystalloid in the ED before admission and generally seem to improve however recent literature demonstrates important differences in the need for renal replacement therapy and mortality.

We have known for some time that NS infusions cause a hyperchloremic metabolic acidosis but were unsure if this was clinically significant [7]. A number of investigators have been looking at this issue and results are coming through that validate concerns regarding use of unbalanced solutions in the more unwell patient. Below are two examples:

1. Large retrospective cohort study compared patients undergoing either elective or emergency general surgical operations who received either NS or a balanced fluid the day of the procedure [8]. Unadjusted in-hospital mortality (5.6% CI 5.3-5.8 vs. 2.9% CI 2.0-4.2; p<0.001) . The number of patients developing major complications (33.7 vs. 23%) were significantly greater in the group that received NS.

Patients that received NS were 4.8 times more likely to require dialysis (p<0.001) and an adjusted odds of death nearly 50% higher.

2. A meta-analysis septic patients that received balanced fluids had a trend towards a lower mortality than those that received NS (OR 0.78 95% confidence interval 0.58-1.05) [10]. All included studies were randomized, controlled trials of adults with severe sepsis or septic shock. The complete analysis included 14 studies and 18,916 patients.

What is a balanced solution?  

Crystalloids that are “balanced” have the presence of an organic anion (such as lactate) and a lower chloride content that more closely resembles the composition of plasma. The difference between the strong cations and the strong anions (the positives and the negatives) in “balanced fluids” is 24-28. In plasma, the actual difference between the sodium (Na) (142 mEq/L) and chloride (Cl) (103 mEq/L) is approximately 39. However by using 24-28 instead of 38-42, you also account for the dilutional effect of the fluid that you are infusing, which dilutes the patient’s albumin and alters the acid-base status [11].  

Another way to think about this is to compare the difference between the positives and negatives of the fluid (the SID or strong ion difference) and compare it to the patient’s bicarbonate concentration. If the SID is less than the patient’s bicarbonate, the fluid will be acidotic; if the SID is greater than the patient’s bicarbonate, the fluid will be alkalotic. Comparing 0.9% NS and LR, the difference between the Na and Cl is 0 (154-154=0). In a patient with a normal bicarbonate concentration (24 mEq/L), the bicarbonate is greater than the SID and so the fluid will be acidotic [12]. The difference between the sodium and chloride in LR is 21 (130-109=21), which is nearly equal to a patient’s normal bicarbonate of 24 mEq/L and so is considered a “balanced fluid;”

For more detail on SID and acid-base status check out  EMCrit Podcast #50.

And yes Hartmanns/ LR costs the same as 0.9% NS.

Anything else?

The series of SAFE studies published between 2004-= and 2011 demonstrated that use of Albumin in severely septic patients improves mortality. This is rarely something we consider during the ED stay but if there are delays to transfer then be aware that it may be helpful.

How does this affect your practice?

For the patient that mild- moderately unwell and needs 1-2 litres of fluid it probably doesn’t matter which crystalloid you use. For patients that are more unwell and at risk of shock or organ injury balanced fluids are better (LR/ Hartmanns in our shop). 


REFERENCES
1. Rivers et al. Early Goal-Directed Therapy in the Treatment of Severe Sepsis and Septic Shock. N Engl J Med 2001;345:1368-1377.
2. Asfar et al. High Versus Low Blood-Pressure Target in Patients with Septic Shock. N Engl J Med 2014;370:1583-1593.
3.Jones et al. Lactate Clearance vs Central Venous Oxygen Saturation as Goals of Early Sepsis Therapy: A Randomized Clinical Trial. JAMA 2010;303(8):739-46.
4. Nagdev et al. Emergency Department Bedside Ultrasonographic Measurement of the Caval Index for Noninvasive Determination of Low Central Venous Pressure. Ann Emerg Med 2010;55(3):290-5.
5. Duus et al. The Reliability and Validity of Passive Leg Raise and Fluid Bolus to Assess Fluid Responsiveness in Spontaneously Breathing Emergency Department Patients. J Crit Care 2015;30(1):217.e1-e5.
6. Marik et al. The Use of Bioreactance and Carotid Doppler to Determine Volume Responsiveness and Blood Flow Redistribution following Passive Leg Raising in Hemodynamically Unstable Patients. Chest 2013;13(2):364-70.
7. Lobo et al. Should Chloride-Rich Crystalloids Remain the Mainstay of Fluid Resuscitation to Prevent ‘Pre-Renal’ Acute Kidney Injury:con. Kidney International 2014;86:1096-1105.
8. Shaw et al. Major Complications, Mortality, and Resource Utilization after Open Abdominal Surgery: 0.9% saline compared to Plasma-Lyte. Ann Surg 2012;255:821-829.
9. Yunos et al. Association between a Chloride-Liberal vs Chloride-Restrictive Intravenous Fluid Administration Strategy and Kidney Injury in Critically Ill Adults. JAMA 2012;308:1566-1572.
10. Rochwerg et al. Fluid Resuscitation in Sepsis. A Systematic Review and Network Meta-Analysis. Ann Intern Med 2014;161:347-355.
11.Morgan TJ. Clinical review: The meaning of Acid-Base Abnormalities in the Intensive Care Unit-Effects of Fluid Administration. Critical Care 2005;9(2):204-211.
12. Carlesso et al. The rule Regulating pH Changes during Crystalloid Infusion. Intensive Care Med 2011;37(3):461-68.

Adapted from an article by Dr Evan Schwartz – In Sepsis, Fluid Choice Matters

EP Monthly May 2015

Tuesday
Apr072015

EDACS roll-out

For years, clinicians have been scratching their heads thinking of how to manage the huge flux of patients streaming into the ED with chest pain.  The feared diagnosis of AMI resulted in the routine use of cardiac biomarkers to risk stratify them with increasing sensitivity... starting from Creatine Kinase to CK-MB, then Troponins (I and T) to the most recent super-sensitive troponins (hsTrop).  This resulted in a myriad of chest pain protocols utilising various time frames with which patients were kept in ED or short stay units to "rule-out" any short term risk of bad cardiac outcomes.  

A routine turnaround time of 6-12hours before a repeat troponin was deemed safe practice in the last decade for patients with low to medium risk patients.  However this increases length of stay which while in itself isn't harmful, has flow-on detrimental effects on ED resource utilisation eg blocking up beds which otherwise could be used for other patients, inducing anxiety, overcrowding, etc.. 

Several scoring systems have been proposed to reduce this turnaround time.  A team led by Dr Louise Cullen came up with a most reasonable so called accelerated diagnostic protocol = EDACS or ED Assessment of Chest Pain Score.  A large number of patients were first identified as "low risk" (score < 16), then given a troponin on arrival and 2 hours.  The results were validated in 2 large centers (Royal Brisbane and Christchurch) and showed very low major cardiac events at 30 days follow up (sensitivity 99-100%).  Non-low risk patients continue down the traditional diagnostic pathway, but more importantly - THINK OF OTHER DIAGNOSES.

Chest pain which sound "atypical" are potential candidates for EDACS (no diaphoresis, no radiation to either arm, pleuritic or reproducible on palpation). Examples :

1. Atypical CP and no RF for IHD in males up to 65yo and females up to 75yo.

2. RF or IHD present but CP is pleuritic (same age as above)

3. Pain that is both pleuritic and reproducible by palpation in any age as long as no RF present.

Remember this scoring system requires a normal ECG, a stable patient and standard follow up procedures. The EDACS score is now incorporated into the CP pathway.  

Saturday
Feb142015

Preoxygenation

One of the most important developments in Emergency Medicine in the past decade is the emphasis on pre-oxygenation and apnoeic oxygenation during advanced airway procedures. The most read Emergency Medicine Article in recent years is a discussion of this practice by the guru of Emergency Critical Care Dr Scott Weingart from New York.

If you are involved in the emergecy management of airways then you should have read this article.

View it right here.

Monday
Dec082014

Play that funky rhythm...

The folks from Annals of Emergency Medicine have published a nice snapshot of the state of the evidence regarding New Onset Atrial Fibrillation (some people call this RAFF - Recent onset Atrial Fibrillation and Flutter).

Basically for patients <65yrs rhythm control confers better outcomes and is best.

For patients over 65 with CCF, valvular disease etc rate control is best.

In fit patients >65yrs  the evidence is not clear and management should be tailored to the individual using a shared decision making approach remembering that the longer the patien is in AF the harder it becomes to get them back into SR.

Don't take my word on it though..check out the article here for yourself. Its short and sweet!

 

Friday
Nov212014

Sepsis Update 

There have been a number of high quality trials published this year that inform our management of severe sepsis.

Click here for a brief summary of the big four.