UMEM Educational Pearls - By Kim Boswell

Resuscitative thoracotomy is a dramatic and heroic procedure used in the emergency department in an attempt to resuscitate a patient in arrest due to trauma. There are a few techniques commonly used, but due to the extreme nature of the procedure no prior randomized controlled trials (RCTs) have been done.

The modified clamshell thoracotomy (MCT) is a technique in which the standard left anterolateral thoracotomy (LAT) is extended across the sternum, but does not involve surgical opening of the right chest. The MCT allows for increased visualization of the mediastinum and thoracic cavity structures. 

Sixteen Emergency trained physicians (approximately half attending and half senior residents) from a level 1 trauma center underwent didactic and skill based training on both the MCT and LAT techniques using fresh, human cadavers. Following training they were randomized based on order of intervention, performing both techniques.

Their thoracotomies were assessed by a board certified surgeon and “success” was determined based on the complete delivery of the heart and cross clamping of the descending aorta. 

Primary outcome: time to successful completion of procedure

Secondary outcomes: successful delivery of the heart from the pericardial sac (as well as time to delivery),  cross clamping of the aorta (and time to clamping),  procedural completion and number of iatrogenic injuries. 

Overall, there was no statistical difference in primary outcome or successful completion between the MCT compared to the LAT (67% vs. 40%). However, 100% of the LAT resulted in some form of iatrogenic injury (rib fractures, lacerations of the diaphragm,/esophagus/heart/lung) compared to 67% of the MCT technique. There was no associated difference in success when previous experience (attending vs. senior resident) were compared. Lastly, MCT was the favored technique of the majority of the study subjects. 

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A recent pilot study was conducted in two centers (Mayo Clinic & Cleveland Clinic Affiliate) and aimed to evaluate if the administration of oral midodrine in early septic shock could decrease the use of IV vasopressors and decrease ICU and hospital length of stay (LOS).  The study was a placebo-controlled, double blinded randomized trial.

This study enrolled:

• 32 adult patients 
• within 24 hours of Sepsis 3 definition who continued to have hypotension (MAP < 70mmHg) after antibiotic & 30mL/kg IVF administration
• 3 doses of midodrine 10mg were administered

The study did not find a statistical difference between the two groups in the use of vasopressors or ICU/Hospital LOS. However, there was a trend in the midodrine group which is suggestive of decreased vasopressor use and ICU/Hospital LOS. 

It is Important to note the study was not powered to determine clinical significance. Overall the trend noted in the midodrine group should encourage further studies that are clinically powered to determine if there is a statistical difference and therefore a potential benefit to early initiation of oral midodrine in septic shock.

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STARRT-AKITrial

The Standard versus Accelerated initiation of Renal Replacement Therapy in Acute Kidney Injury

The development of acute kidney injury (AKI) in the critical care setting portends a greater morbidity and mortality for patients. Additionally, it places the patient at high risk of complications and requires a greater use of resources. Several studies in the past have examined if the timing of initiation of renal replacement therapy (RRT) would result in a mortality benefit, but have failed to demonstrate consistent outcomes.

The STARRT-AKI trial was a multinational, randomized controlled trial designed to determine if early initiation of RRT in critically ill adult patients with AKI lowered the risk of 90-day mortality. The Kidney Disease Improving Global Outcomes (KDIGO) classification was used to define AKI and over 2900 patients were randomly assigned to two groups over a 4 year period. Exclusion criteria included: recent RRT, a renal transplant within the preceding year, advanced CKD, an overdose necessitating RRT, or a strong suspicion of obstruction or autoimmune/vascular cause of their AKI.

Groups:

• The accelerated strategy group
  • Initiation of RRT within 12 hours of meeting eligibility criteria (AKI based on KDIGO definition)
• The standard strategy group –
  • General goal of withholding RRT unless the patient met the following specific parameters:
  • K+ >6.0,  pH <7.20,  HCO3 <12mmol/L,  moderate ARDS with clinical picture concerning for volume overload, or persistent AKI >72hr after randomization

Outcomes/Results:

• The study’s primary outcome measure was all cause mortality at 90 days
  •  There was no significant difference between the groups
  •  P=0.92 with RR 1.00
• Secondary outcomes evaluated several things including ventilator and vasoactive free days, hospital length of stay, number of days without RRT at 90 days as well as adverse events directly related to RRT
  • Interestingly, at 90 days, the patients in the accelerated strategy group were more likely to have ongoing RRT needs at 10.4% compared to the standard strategy group at 6.0% (not statistically significant).
  •  Overall, no significant difference between the groups when assessed for death in the ICU, major adverse events, or with regard to hospital length of stay.

Take home points:

• This was a well done, well randomized trial from many countries and ICU settings
• No significant mortality benefit between groups at 90 days
• Interestingly, the patients in the accelerated group were more likely to have suffered adverse events related to RRT and were more likely to be dependent on RRT at 90 days
  • It is unclear why this is, but suggestive that early initiation of RRT may compromise the intrinsic healing of the kidney
  • Emphasizes a greater risk for adverse events without clear benefit
• Ultimately, the decision to initiate RRT should be based on the patient’s clinical picture, acid/base status, electrolyte abnormalities, and volume status and NOT on a general trend of their renal indices.

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We all know the frustration that comes with the phone call from radiology asking if you “really want IV contrast” for your patient’s CT because the creatinine is elevated…

Recently, a joint statement was published between the American College of Radiology and the National Kidney Foundation regarding the safety of IV contrast in patients with kidney disease. The recommendations are based on GFR and apply to those with both chronic kidney disease as well as those who have an acute kidney injury. Summary points of the statement are below:

• Prophylaxis is not indicated with a GFR > 45mL/min
• Prophylaxis should be given to patients with a GFR < 30mL/min (Other conditions such as heart failure or hypervolemia may preclude prophylaxis based on clinical judgement)
• Prophylaxis is NOT indicated in those with GFR > 30mL/min even if patients also have diabetes, dialysis dependent renal failure or those at risk of heart failure.
• High risk patients (Recent AKI, borderline GFR, or numerous risk factors) with GFR 30-44mL/min can be considered for prophylaxis based on clinical judgement

• Preferred prophylaxis is with isotonic fluid, such as normal saline. Volumes and timing are uncertain but should begin prior to contrast administration.
• Bicarbonate and N-acetylcysteine are not recommended fluids for prophylaxis

• There is no need for acute HD or CRRT following contrast administration in ESRD patients

Every decision to use contrast should be made based on clinical need for contrast as well as individual patient risk factors and underlying disease processes.

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Please see Part I from 12/24/19 for information about causes and symptoms.

Diagnosis:

The diagnosis of HLH is challenging, as it often mimics sepsis or other critical illness.  A high index of suspicion is vital and early treatment, imperative.

Diagnostic criteria in adults include 5 of 8 of the following:

(based on the Hscore:  https://www.mdcalc.com/hscore-reactive-hemophagocytic-syndrome#use-cases)

·      Presence of known immunosuppression

·      Fever >38.5

·      Splenomegaly or hepatomegaly

·      Cytopenias

·      Ferritin elevation (usually markedly elevated)

·      Elevated triglycerides

·      Low fibrinogen level

·      ALT elevation

Immunologic testing:

·      CD25 levels are elevated

·      NK cell activity is low or absent

In adults, highly elevated ferritin levels (>10,000) are highly suggestive of HLH.

Elevated LDH, Ddimer, and multisystem organ dysfunction (especially CNS) is common.

Immunologic testing should not delay treatment if other lab values suggestive of HLH.

Treatment:

Given the high mortality rate, treatment should be initiated if the symptoms are suggestive of HLH.  In the setting of a critically ill individual, hematology consultation is warranted for treatment guidance as treatment is based on lab values and clinical picture. Treatment usually starts with high dose , IV steroids (dexamethasone) and may include chemotherapeutic agents, such as Etoposide. For those patients with CNS involvement, intrathecal chemotherapy is usually a mainstay of treatment

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Hemophagocytic Lymphohistiocytosis (HLH) – Part I

A rare, but important disease that is becoming more widely recognized and more frequently diagnosed. This disease, while uncommon, is rapidly progressive and caries a high mortality rate.

Causes are not completely understood, but involve abnormal activation of the immune response due to a failure of the typical downregulation in hyperinflammatory processes.

Two types exist:

            Congenital/Familial – genetic predisposition which usually requires a triggering event to occur

            Acquired – occurs in adults with no known predisposition (often have underlying genetic predispositions) – triggering events include infections , immunodeficiency, rheumatologic disorders, and malignancy in addition to many others.

Diagnosis is challenging due to the wide variety of symptoms and constellation of symptoms, which often mimic more common infections/sepsis presentations.  Common symptoms include the following:

• Fever – 95 percentSplenomegaly – 89 percent 
• Bicytopenia – 92 percent (most often anemia and thrombocytopenia) 
• Hypertriglyceridemia or hypofibrinogenemia – 90 percent

Symptoms can, and do, occur in any body system – rashes, conjunctivitis, DIC, LFT abnormalities,  hypotension/shock, and respiratory failure are all common concomitant findings in the presentation of HLH

More on the specific diagnosis and treatment to follow in part II...

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Most non-OB physicians experience some fear or anxiety over taking care of the average pregnant patient. There are two patients to consider when caring for these women. Critical illness adds another layer of complexity to an already challenging patient population. Due to the normal physiologic changes that occur during pregnancy there are specific and important factors to be aware of when considering and preparing for intubation.

• Difficult intubations occur up to 5% of pregnant women.
• Edema occurs in the OP regions resulting in a narrowed OP diameter, especially with advancing gestational age. A smaller than anticipated ET tube might be necessary.
• Weight gain and/or obesity make visualization difficult Consider the ramp position to bring the external auditory meatus and the sternal notch into a horizontal line.
• Aortocaval compression decreases blood return to the heart and can result in hypotension on induction. Consider the use of a wedge under the patient’s right hip to decrease compression during intubation, especially those in later stages of pregnancy.
• Risk of aspiration is increased due to decreased lower esophageal sphincter tone. Consider administering metoclopramide prior to intubation which selectively increases esophageal sphincter.
• Functional residual volume in addition to increased oxygen consumption and metabolic demand lead to quicker desaturations and a greater intolerance to hypoxia and apnea. 
• Be prepared with back up or adjunctive airway options including a video laryngoscope (like Glidescope), an LMA or a supraglottic airway. Although the LMA and supraglottic airways are rescue options in the setting of failed ET intubation, they can often adequately oxygenate and ventilate while urgently consulting with anesthesia colleagues in order to obtain a definitive airway.

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Rapid Assessment of the RV on Bedside Echo

There are several causes of acute RV dysfunction resulting in a patient presenting to the ER with unstable hemodynamics. Some of these include acute cor pulmonale, acute right sided myocardial infarction and acute submassive or massive pulmonary embolism. While bedside assessment of the LV function is often performed by the ED physician, simultaneous evaluation of the RV can provide crucial information that can help guide therapeutic decisions to prevent worsening of the patient’s clinical condition. A rough guideline to determine RV size and function is below using the apical 4 chamber view.

Normal RV size :            <2/3 the size of the LV

Mildly enlarged RV :       >2/3 the size of the LV, but not equal in size

Moderately enlarged RV:  RV size = LV size

Severely enlarged RV:      RV size > LV size

Patients who are found to have RV dilation should be given fluids in a judicious fashion as the RV is not tolerant of fluid overload. Early diagnosis of the cause of acute RV failure should be sought to guide definitive therapy, but early institution of inotropic support should be considered. Frequent reassessments of biventricular function during resuscitation should be performed.

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Attachments

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