UMEM Educational Pearls - Critical Care

Intraosseous (IO) placement is a rapid and reliable method for obtaining venous access in critically ill patients; previous studies demonstrated that everything from vasopressors to packed RBCs can be infused through it.

This prospective observational study compared the first-pass success rate and time to successful placement of IO versus landmark-based (i.e., not ultrasound guided) central-line placement (femoral or subclavian access) during medical emergencies (e.g., cardiac arrest) in an inpatient population.

The first pass success rate for IO was found to be significantly higher than the landmark technique (90% vs. 38%) and placement was significantly faster for IOs (1.2 vs. 10.7 minutes).

Despite the fact that this study did not directly compare IO to ultrasound guided line placement, this study demonstrates that IO is a rapid and effective means to obtain central access during patients with emergent medical conditions.

Bottom-line: Consider placing an IO line when rapid central access is necessary.

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Category: Critical Care

Title: High Flow Nasal Cannula for Hypoxemia

Keywords: HFNC, high flow, vapotherm, nasal cannula, respiratory failure, non invasive ventilation (PubMed Search)

Posted: 6/2/2015 by Feras Khan, MD
Click here to contact Feras Khan, MD

High Flow Nasal Cannula (HFNC) in acute respiratory hypoxemia

  • HFNC has been used for a variety of patients with respiratory distress (See previous pearl: https://umem.org/educational_pearls/2411/)
  • The benefits include:
  1. Low levels of positive pressure in the upper airways
  2. High flow rates, titratable oxygen levels, humidied air, more comfort than NIV
  3. Decreases physiological dead space by flushing out CO2 therefore improving oxygenation
  • A recent trial published in NEJM looked at using HFNC in patients with respiratory failure

The Trial:

  • Patients without hypercapnia and with acute hypoxemic respiratory failure (PaO2/FiO2 <300 or less) were randomized to HFNC, standard oxygen therapy via face mask, or non-invasive positive pressure ventilation (NIV).
  • Primary outcome was proportion of patients intubated at day 28
  • 310 patients in European ICUs

Results:

  • Intubation rate (p=0.18): 38% in the HFNC; 47% in the standard group; 50% in the NIV
  • Number of ventilator free days at day 28 was significantly higher in the HFNC
  • Higher mortality at 90 days with NIV
  • No difference in intubation rates but there were more ventilator free dates as well as a lower 90 day mortality

Bottom line:

Consider using HFNC prior to or while deciding on intubation in patients with hypoxemic respiratory failure usually due to pneumonia

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Stress-Induced Cardiomyopathy

  • Stress-induced cardiomyopathy (SIC) can be seen in a variety of critical illnesses, especially severe neurologic conditions.
  • SIC is believed to be caused by excess sympathetic stimulation of the myocardium.
  • When managing a patient with SIC, limit further catecholamine exposure by avoiding vasopressors if possible.
  • If the patient requires inotropic support, consider using an agent without catecholamine activity, such as milrinone.

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Advances in Catheter-Directed Therapy for Acute PE - The PERFECT Registry

Earlier this month, initial results from the multicenter PERFECT registry (Pulmonary Embolism Response to Fragmentation, Embolectomy, and Catheter Thrombolysis) were released. In this study, 101 consecutive patients with massive or submassive PE were prospectively enrolled to receive early catheter-directed therapy.

Inclusion criteria:

  • Massive or submassive PE
  • Presented within 14 days of symptoms
  • Had CT evidence of proximal filling defect (main or lobar pulmonary artery)
  • Age > 18 years old
  • Had no contraindications to therapeutic anticoagulation
  • PE not related to tumor thrombus

Therapy provided:

  • Submassive PE: Low-dose (0.5 - 1.0 mg/hr of urokinase) infusion directly into clot
  • Massive PE: catheter-directed mechanical or pharmacomechanical thrombectomy followed by low-dose thrombolytic therapy used for submassive PE patients.

Outcomes: Clinical success (stabilization of hemodynamics, improvement in pulmonary hypertension and/or right heart strain, and survival to discharge) was achieved in 86% of patients with massive PE and 97% of patients with submassive PE. There were no major procedure-related complications or major bleeding events.

Bottom Line: In patients with massive or submassive pulmonary embolism, there is growing evidence that early catheter-directed therapy may become first-line therapy for selected patients.

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There is little debate that ultrasound-guided central lines are safer, faster, and more reliable compared to a landmark technique; there is some debate, however, as to whether the short axis (SA) or long axis (LA) approach is the best (see clips below).

The referenced study compared the SA and the LA technique for both the internal jugular (IJ) and subclavian (SC) venous approach. The authors measured number of skin breaks, number of needle redirections, and time to cannulation for each method.

This study demonstrated that the LA technique for subclavian placement had fewer redirections, decreased cannulation time, and fewer posterior wall punctures as compared to the SA. With respect to the IJ approach, the LA was also associated with fewer redirections than the SA view.

Bottom line: Consider the long-axis technique the next time you place an ultrasound guided central line.

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Category: Critical Care

Title: Safety of thoracentesis

Keywords: thoracentesis, pleural effusion, critical care (PubMed Search)

Posted: 5/4/2015 by Feras Khan, MD
Click here to contact Feras Khan, MD

Safety of Thoracentesis

  • Thoracentesis is routinely performed in both acute and non-acute patients while patients are admitted to the hospital for respiratory distress
  • A recent 12 year cohort study of 9320 thoracenteses was published from Cedars-Sinai Hospital
  • The clinicians that perform these procedures are well experienced
  • The most common complications include pneumothorax, re-expansion pulmonary edema, and bleeding

Results after 24 hours of followup post-procedure

  • 0.61% of iatrogenic pneumothoraces
  • 0.01% rate of re-expansion pulmonary edema
  • 0.18% of bleeding episodes

Other interesting points:

  • Pneumothorax was associated with removing >1500 mL of fluid and more than one needle pass
  • Ultrasound was routinely used
  • A safety-tipped needle/catheter was used
  • Fluid was removed by manual hand pumping (not vacuum bottles)
  • CXR only done post-procedure if patients were symptomatic
  • No blood products were given for low platelets or thrombocytopenia

Bottom line: Use your ultrasound to direct your tap and dont take out more than 1500 mL routinely

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SIRS and Severe Sepsis Screening

  • Sepsis remains one of the most common critical illnesses managed by emergency medicine and critical care physicians.
  • Many EDs and ICUs have screening protocols for early detection of the patient with sepsis. Most protocols use the systemic inflammatory response syndrome (SIRS) as a central component of early identification.
  • A recent study stresses caution when simply using the SIRS criteria to screen for severe sepsis:
    • Retrospective review of the ANZICS Adult Database
    • Divided patients into SIRS-positive ( 2 SIRS criteria with at least 1 organ failure) and SIRS-negative ( < 2 SIRS criteria with at least 1 organ failure)
    • 109,663 patients
    • 12% of patients diagnosed with severe sepsis or at least 1 organ failure had < 2 SIRS criteria at admission.
    • Mortality for the SIRS-negative cohort remained relatively high at 16.1%
  • Take Home Point
    • Using the SIRS criteria to screen patients for severe sepsis will miss 1 out of every 8 patients with infection and organ dysfunction.

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Category: Critical Care

Title: Updates in the Management of Large Hemispheric Infarction

Keywords: large hemispheric infarct, acute ischemic infarct, stroke (PubMed Search)

Posted: 4/20/2015 by John Greenwood, MD (Emailed: 4/21/2015) (Updated: 4/21/2015)
Click here to contact John Greenwood, MD

Updates in the Management of Large Hemispheric Infarction

Large hemispheric infarctions (LHI) are estimated to occur in 2-8% of all hospitalized ischemic strokes and 10 15% of all MCA territory infarcts. LHI carry high rates of morbidity and mortality, in fact, if left untreated associated cerebral edema can rapidly progress to transtentorial herniation and death in 40 80% of patients.

Recognized risk factors for progressive cerebral edema include:

  • NIH stroke scale > 20 in dominant hemispheric infarct
  • NIH stroke scale > 15 in nondominant hemispheric infarct
  • Rapid decline in level of consciousness (LOC) indicates effect on contralateral hemisphere (due to ipsilateral swelling)

Evidence based medical strategies for LHI include:

  • Positioning: Elevation of the head of the bed (HOB) > 30 degrees
  • Glucose control: 140 180 mg/dL (hyperglycemia associated with increased ICP and progression to hemorrhagic conversion)
  • Blood pressure control: 15% reduction MAP over 24 hours if BP exceeds 220/120 (likely best accomplished with nicardipine infusion to avoid overcorrection)
  • Osmotic therapy: In the deteriorating patient, consider hypertonic saline (23%) with goal Na of 160 mEq/L or mannitol with goal plasma osmolality of 320 mOsm/kg.
  • Adjunctive therapies: Prevent fever and hypercapnea

Prophylactic hemicraniectomy

  • Consider early neurosurgical consultation for patients with LHI as newer evidence suggests prophylactic hemicraniectomy may improve survival if performed within 24 48 hours.

Bottom Line: Early recognition of large hemispheric stroke is critical as it is associated with a high rate of morbidity and mortality. Aggressive medical management and early neurosurgical involvement may improve outcomes.

References

  1. Zha AM, Sari M, Torbey MT. Recommendations for management of large hemispheric infarction. Curr Opin Crit Care. 2015;21(2):91-8.

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Question

You decide to do a R.U.S.H. exam on your hypotensive patient and perform an apical four-chamber view.You see one of the two clips below; are there any tricks to figure out which is the left ventricle and which is the right ventricle?

Show Answer

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  • A recent meta-analysis found that non-invasive ventilation can improve survival in acute care settings.
  • Consider using NIPPV in:
    • COPD exacerbation
    • Obesity hypoventilation syndrome
    • Asthma
    • Hypoxemic respiratory failure
    • Cardiogenic pulmonary edema
    • ARDS
  • Make sure to reassess your patients for improvement within one hour of applying NIPPV. If gas exchange has not significantly improved then endotracheal intubation and mechanical ventilation should be considered.
  • Adverse effects:
    • Gastric distension
    • Pressure ulcers on the face
    • Can be uncomfortable
  • In cardiogenic pulmonary edema there are cardiac performance benefits:
    • Decreases preload
    • Decreases left ventricular afterload
    • Improved cardiac ouput

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Mechanical Ventilation in the ED

  • Emergency physicians (EPs) intubate patients on a daily basis.  Due to prolonged lengths of stay for many of these patients, the EP must manage the ventilator during the crucial early hours of critical illness.
  • Despite the marked increase in critically ill patients, emergency medicine residents receive very little training in mechanical ventilation (MV).1
  • In addition, recent literature has demonstrated some common themes regarding MV in the ED.2,3
    • Use of higher than recommended tidal volumes
    • Infrequent use of lung protective ventilation strategies
    • Infrequent monitoring of plateau pressures
  • Take Home Points
    • Pay attention to tidal volume
    • Monitor and maintain plateau pressures < 30 cm H2O

Show References


Category: Critical Care

Title: Stop looking for the "Best PEEP", aim for a "Better PEEP"

Keywords: mechanical ventilation, ARDS, PEEP (PubMed Search)

Posted: 3/24/2015 by John Greenwood, MD (Updated: 10/19/2020)
Click here to contact John Greenwood, MD

 

Stop looking for the “Best PEEP”, aim for a “Better PEEP”

Mechanical ventilation settings in the patient with acute respiratory distress syndrome (ARDS) need to provide adequate gas exchange and prevent ventilator induced lung injury (VILI). Positive end-expiratory pressure (PEEP) is often prescribed with consideration of the patient’s FiOrequirement, estimated chest wall compliance, and hemodynamic tolerance. 

So what is the best strategy for PEEP prescription?

In a recent review, Gattinoni & colleagues analyzed a number of the recent studies examining PEEP optimization.  In this paper, the authors conclude that there is no “Best PEEP,” and regardless of the level chosen there will be some degree of intratidal recruitment-derecruitment and VILI.  They go on to recommend a PEEP prescription strategy that reflects the severity of ARDS using the patient’s PaO2/FiO2 or P/F ratio.  

  • Mild ARDS (P/F 200 – 300): 5-10 cm H2O
  • Moderate ARDS (P/F 100 – 200): 10-15 cm H2O
  • Severe ARDS (P/F < 100): 15-20 cm H2O
     

Bottom line: There is no “Best PEEP” however, a “Better PEEP” is one that is primarily tailored to the severity of the patient’s ARDS, but also compensates for chest wall resistance and minimizes hemodynamic compromise.    

 

References

  1. Gattinoni L, Carlesso E, Cressoni M. Selecting the 'right' positive end-expiratory pressure level. Curr Opin Crit Care. 2015;21(1):50-7.
  2. ARDSnet PEEP table: http://www.ardsnet.org/system/files/Ventilator%20Protocol%20Card.pdf

 

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Category: Critical Care

Title: The results are in! The ProMISe Trial

Posted: 3/17/2015 by Haney Mallemat, MD (Emailed: 3/18/2015) (Updated: 3/18/2015)
Click here to contact Haney Mallemat, MD

The results of a multi-center trial from the UK, the ProMISe trial, were just released and it confirms what two prior studies (i.e., ProCESS and ARISE) have already shown; there does not appear to be any difference in mortality when septic patients are treated with a strategy of early-goal directed therapy as compared to usual care.

Patients were included in the ProMISe trial if they were in septic shock and were then randomized to either the EGDT group (630 patients) or the usual care group (630 patients); a total of 1,260.

The primary end-point was all cause mortality at 90 days and there was no difference shown in the primary outcome. There were no differences found in the measured secondary outcomes (e.g., serious adverse events)

This trial adds to the evidence that septic patients may not benefit from protocolized (i.e., EGDT) care versus usual care. One explaination why, is that our "usual care" in 2015 has significantly changed since the introduction of EGDT in 2001.

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Category: Critical Care

Title: Transfusion in Major Trauma: The PROPPR Trial

Keywords: massive transfusion, trauma, bleeding, critical care, severe trauma, PROPPR (PubMed Search)

Posted: 3/10/2015 by Feras Khan, MD
Click here to contact Feras Khan, MD

Transfusion in Major Trauma: The PROPPR Trial

What should we be transfusing in major trauma?

  • Should we aim towards 1:1:1 ratios or is that unnecessary? Most trauma centers have gone towards a 1:1:1 ratio or a 1:1:2 ratio with a greater percentage of RBCs transfused in the latter
  • Our strategy should be to avoid coagulopathy, acidosis, and hypothermia
  • This trial looks at transfusion of Plasma, Platelets, and RBCs in a 1:1:1 vs a 1:1:2 ratio
  • Is it safe to give 1:1:1 ratios?

The Trial

  • RCT, Non-blinded
  • 12 Trauma Centers in North America
  • 15 years or older; highest level trauma activation
  • Predicted to receive massive transfusion
  • Transfusions stopped when clinically indicated

Results

  • 24 hour or 30 day mortality no significant difference
  • Post-hoc analysis: death by exsanguination (9% vs 15%) in the 1st 24hrs was significantly decreased in the 1:1:1 group
  • Achieved hemostatis (86% vs 78%; p = 0.006) greater in the 1:1:1 group

Conclusions

  • Was not powered to detect a difference of less than 10% in mortality
  • There was less mortality from exsanguination in the 1:1:1 ratio.
  • Worth noting that platelets given first in 1:1:1 group (in control group 6 U and 3 FFP given prior to platelets)
  • There was some "catch up" in the 1:1:2 group (after the initial transfusions, these patients got more than expected plasma and platelets based on INR/Plt counts)
  • TEG was used in the majority of the patients and TXA was used in a majority of patients (but similar in both groups)

How does this affect my practice?

A 1:1:1 transfusion practice is safe and can decrease mortality from hemorrhage in major trauma

Other points: control bleeding, permissive hypotension, avoid crystalloids, use TEG to guide therapy (TXA etc)

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High-Flow Nasal Cannula for Apneic Oxygenation

  • In recent years, much has been written about the use of apneic oxygenation for patients who require endotracheal intubation (ETI).
  • Critically ill patients often have little cardiopulmonary reserve and can rapidly desaturate during ETI.
  • High-flow nasal cannula (HFNC) devices can deliver heated, humidified O2 up to 60 L/min and can provide a modest amount of positive pressure.
  • A recent study evaluated the use of a HFNC device for apneic oxygenation in ICU patients requiring ETI:
    • Prospective, quasi-experimental, before-after study
    • 101 patients in a single ICU in France
    • Compared NRB + nasal cannula to HFNC for preoxygenation/apneic oxygenation
    • Prevelance of severe hypoxemia (SpO2 < 80%) was significantly lower in the HFNC group
  • Clinical Application: Consider using HFNC for apneic oxygenation in critically ill patients with mild-to-moderate hypoxemia who require ETI.

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The Role of the CVP in a Post- “7 Mares” Era
 

The role for using central venous pressure (CVP) as a measure of volume responsiveness has largely fallen out of favor over the years.1 There are certainly better indices for fluid responsiveness, but don’t be fooled – the CVP isn’t a one trick pony.  In fact, a high or rapidly rising CVP should raise a significant concern for impending cardiovascular collapse.

Consider the following differential diagnosis in the patient with an abnormally high or rising CVP ( >10 cm H2O).

  • Excessive pressures outside of the heart or impediments to venous return (juxta-cardiac pressures)
    • Cardiac tamponade
    • Auto PEEP or breath stacking during mechanical ventilation
    • Tension pneumothorax
  • Venous return that’s more than the right ventricle can handle
    • RV failure
    • Severe tricuspid valve disease
    • Massive increase in pulmonary vascular resistance (massive PE, pulmonary hypertension, ARDS, LV failure)

Bottom Line: In a time where the utility of the CVP has been largely dismissed, remember that an abnormal CVP offers great deal of information beyond a simple measure of volume status.

 

References

  1. Marik PE, Baram M, Vahid B. Does central venous pressure predict fluid responsiveness? A systematic review of the literature and the tale of seven mares. Chest. 2008;134(1):172-8.
  2. Berlin DA, Bakker J. Starling curves and central venous pressure. Critical Care. 2015;19(1):55.

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As the cold and snow rips through the United States, hypothermia is a major concern because each year approximately 1,300 Americans die of hypothermia.

Classification of hypothermia:

  • Mild (32-35 Celsius): shivering, hyperventilation, tachycardia, but patients are usually hemodynamically stable.
  • Moderate (28-32 Celsius): CNS depression, hypoventilation, loss of shivering, risk of arrhythmias, and paradoxical undressing
  • Severe (<28 degrees Celsius): increased risk of ventricular tachycardia/fibrillation, pulmonary edema, and coma

The risk of cardiac arrest increases when the core temperature is less than 32 Celsius and significantly rises when the temperature is less than 28 Celsius. Rapid rewarming is required as part of resuscitation should cardiac arrest occur.

A rescue therapy to consider (when available) is extra corporeal membrane oxygenation (ECMO). ECMO not only provides circulatory support for patients in cardiac arrest, but allows re-warming of patients by 8-12 Celsius per hour.

Some studies quote survival rates of 50% with hypothermic cardiac arrest patients receiving ECMO versus 10% in similar patients who do not receive ECMO.

As winter lingers in the United States, consider speaking to your cardiac surgeons now to plan an Emergency Department protocol for hypothermic patients that may require ECMO.

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Category: Critical Care

Title: Updates in preventative strategies in the ICU

Keywords: VAP, chlorhexidine baths, subglottic suctioning (PubMed Search)

Posted: 2/10/2015 by Feras Khan, MD
Click here to contact Feras Khan, MD

Updates in preventative strategies in the ICU

Preventing Ventilator Associated Pneumonia (VAP)

  • Traditionally ICUs use techniques such as head of bed elevation> 30 degrees, chlorhexidine mouth rinses, reduced sedation, and controlling cuff pressure between 20-30 cm H2O to reduce VAP
  • A new trial confirms that subglottic suctioning also reduces VAP
  • Endotracheal tubes are made with a suction line along the edge with fenestrations below the vocal cords and above the cuff
  • This is hooked to wall suction removing secretions before they are aspirated
  • VAP rates are very low in the US (most likely due to under-reporting)
  • It is reported at around 15 VAPs/ 1000 ventilator days in Europe

The trial

  • 5 ICUs in Belgium; 352 total patients with suctioning vs control were randomized
  • Reduced incidence of confirmed VAP 9% vs 18%, decrease ventilator days 10 vs 20 and antibiotic use 7% absolute reduction

Bottom Line

  • More expensive around $20 or more vs $1 for a regular ETT
  • NNT around 11 to prevent one VAP: it is cost efficient
  • Use them in patients who will remain intubated for > 48hrs (not elective surgical patients)

Daily bathing with chlorhexidine does not reduce health care associated infections

  • It is believed that daily bathing with chlorhexidine antibiotic washes decrease rates of infection in the ICU; this is debatable

The trial

  • One center, 5 ICUs, 9340 patients
  • 10 week cleaning period followed by a two week washout then crossover to the alternate treatment (non-antibiotic washes)
  • Looking for CLABSIs, CAUTIs, VAP and C. diff infections
  • 55 infections occurred in the chlorhexidine group; 60 in the control goup.
  • 2.86 per 1000 patient days (chlorhexidine group) vs 2.9 per 1000 patient days (control)

Bottom Line

  • Does not appear to be helpful (perhaps specific patient groups such as bone marrow units may benefit)
  • More expensive to use these washes and can lead to resistance
  • Very well designed study with a variety of ICUs used (although one center)

Show References


Hypertensive Emergency Pearls

  • It is well known that a hypertensive emergency is not defined by an arbitrary blood pressure reading.  Rather, it is characterized by the presence of end-organ dysfunction, often due to a sudden increase in sympathetic activation.
  • When treating patients with a hypertensive emergency, consider the following:
    • Many are hypovolemic due to a pressue-induced natriuresis - give them fluids and avoid diuretics.
    • BP should be reduced in a controlled manner using short-acting titratable intravenous agents. Rapid reductions in BP can lead to organ hypoperfusion.
    • Avoid oral, sublingual, and transdermal medications until end-organ dysfunction has resolved.
    • Clevidipine is the newest agent
      • A third-generation dihydropyridine
      • Relaxes arteriolar smooth muscle
      • Rapid onset (2-4 min) and short acting (5-15 min)
      • Compares favorably with nicardipine in available studies

Show References


Category: Critical Care

Title: Extracorporeal Treatment Strategies for Acute Methanol Poisoning (When to Dialyze)

Keywords: Methanol, toxicology, methanol toxicity, critical care (PubMed Search)

Posted: 1/20/2015 by John Greenwood, MD (Emailed: 1/27/2015) (Updated: 1/30/2015)
Click here to contact John Greenwood, MD

 

Extracorporeal Treatment Strategies for Acute Methanol Poisoning (When to Dialyze)

 

Methanol toxicity is classically included in the differential for the intoxicated patient presenting to the ED. Add a negative EtOH level, anion/osmolar gap, blindness and you have yourself a slam dunk diagnosis. The goal is to stop the liver from metabolizing methanol to formic acid. Outside of fomepizole (or old school ethanol therapy), dialysis is often discussed, but when should you actually get the nephrologist on the phone?

This month the Extracorporeal Treatments in Poisoning Workgroup released a systematic review and consensus statement to help clinicians decide when to pull the HD trigger. Their suggestions are below.

When to start HD:

  1. Neurologic dysfunction: Coma, seizures, new vision deficits
  2. Metabolic acidosis: blood pH ≤7.15 or persistent metabolic acidosis despite adequate supportive measures & antidotes
  3. Serum anion gap higher than 24 mmol/L
  4. Serum methanol concentration:
    • > 700 mg/L (21.8 mmol/L) if fomepizole therapy is given
    • > 600 mg/L or 18.7 mmol/L if ethanol treatment is given
    • > 500 mg/L or 15.6 mmol/L in the absence of an alcohol dehydrogenase blocker

Which Modality: Intermittent HD (IHD) should be used over continuous renal replacement therapies (CRRT), as you can clear the toxin faster with higher HD flows.

When to stop HD: Extracorporeal treatment can be terminated when the methanol concentration is less than 200 mg/L or 6.2 mmol/L and a clinical improvement is observed.

Bottom Line:  Consider early hemodialysis in most patients presenting with methanol toxicity.  Clinical exam and routine lab testing will likely provide enough information to determine the need for IHD, but specific methanol levels can be helpful to guide adjunctive treatment options.

 

Reference

Roberts DM, Yates C, Megarbane B, et al. Recommendations for the Role of Extracorporeal Treatments in the Management of Acute Methanol Poisoning: A Systematic Review and Consensus Statement. Crit Care Med. 2015;43(2):461-472.

 

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