UMEM Educational Pearls - Critical Care

Category: Critical Care

Title: B12 in septic shock

Keywords: Septic Shock, Vitamin B12, Hydroxocobalamin, sepsis (PubMed Search)

Posted: 10/8/2024 by Jordan Parker, MD
Click here to contact Jordan Parker, MD

Background:

Septic shock is a severe and common critical illness that is managed in the emergency department.  Our current foundation of treatment includes IV fluids, empiric antibiotic coverage, vasopressor therapy, source control and corticosteroids for refractory shock.  The levels of nitric oxide (NO) and hydrogen sulfide (H2S) are elevated in sepsis and associated with worse outcomes.  Hydroxocobalamin is an inhibitor of NO activity and production and a scavenger of H2S [1,2].  Most of the current data is limited to observational studies looking at hydroxocobalamin in cardiac surgery related vasodilatory shock with few case series and reports for use in septic shock.  The available data has shown an improvement in hemodynamics and reduction in vasopressor requirements in various vasodilatory shock states [2].  Chromaturia and self-limited red skin discoloration are common side effects but current data has not shown significant adverse events [3,4].  Patel et al, performed a phase 2 single-center trial to evaluate use of high dose IV hydroxocobalamin in patients with septic shock. 

Study:

  • Single-center, double-blind RCT, 20 patients (10 hydroxocobalamin, 10 placebo)
  • Included patients >/= 18 years of age within 48 hours of admission with a diagnosis of septic shock (based on Sepsis 3 criteria) who were receiving norepinephrine (NE) of 0.10 mcg/kg/min for at least 15 minutes or an equivalent dose of alternative vasopressor.
  • Notable exclusion criteria were patients with a history of urinary calcium oxalate crystals, active hemolysis or bleeding, impending death.
  • Intervention group received a single dose of 5 grams of IV hydroxocobalamin administered over 15 minutes
  • Primary outcome – Feasibility Study (*Initial primary outcome was reduction in vasopressor dose but was changed during the COVID-19 pandemic to a feasibility study*)
  • Secondary outcomes – Change in H2S levels and NE dose from randomization to 30 minutes and 3 hours after IV hydroxocobalamin.

Results

  • Achieved feasibility with enrollment goal, receiving intervention, no contamination and good follow up.
  • For secondary outcomes the study group showed a statistically significant relative decrease in vasopressor dose compared to placebo at 30 minutes (-36% vs 4%, p < 0.001) and 3 hours after infusion (-28% vs 10%, p = 0.019). 
  • Non-statistically significant reduction in H2S levels in the intervention group compared to placebo.
  • Tertiary outcomes of hospital mortality, ICU mortality, ICU and vasopressor free days did not show any significant difference between the groups. (The study was not designed with the power to look for a difference in these outcomes).  

Take home

There is a low risk of serious adverse events from high dose hydroxocobalamin use [3,4].  For now, it may be reasonable to consider in cases of septic shock refractory to standard care but there isn’t enough data to support its regular use yet.

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Category: Critical Care

Title: Albumin or Crystalloids: What do we give?

Keywords: albumin, crystalloid, septic shock, mortality (PubMed Search)

Posted: 10/1/2024 by Quincy Tran, MD, PhD
Click here to contact Quincy Tran, MD, PhD

Title: Albumin Versus Balanced Crystalloid for the Early Resuscitation of Sepsis: An Open Parallel-Group Randomized Feasibility Trial— The ABC-Sepsis Trial

Settings: 15 ED in the United Kingdom. This study is a feasibility study but it looked at mortality as a primary outcome.
Participants
•    Patients with Sepsis, with their National Early Warning Score (NEWS) ? 5 (These patients have estimated mortality of 20%). IV fluid resuscitation needs to be within 1 hour of assessment.
•    300 Patients were randomized to receive balanced crystalloids or 5% human albumin solution (HAS) only, within 6 hours of randomization.
Outcome measurement: 30-day mortality, Hospital length of stay (HLOS)
Study Results:
•    The median time for receiving IV fluid from randomization was 41 minutes (HAS) vs. 36 minutes (crystalloids).
•    Total volume of IV fluid per Kg  in first 6 hours 14.5 ml/kg  (HAS) vs. 18.8 ml/kg (crystalloids).
•    Other interventions (vasopressor, Renal replacement therapy, invasive ventilation) were similar.
•    Complications (AKI, pulmonary edema, allergy) were lower for Crystalloids group
•    Median hospital LOS = 6 days for both groups.
•    90-day mortality: 31 (21.1%) (HAS) vs. 22 (14.8%) (Crystalloids), OR 1.54 (95% 0.8-2.8)
Discussion:
•    Total volumes for resuscitation in the first 6 hours was 750 ml (HAS) and 1250 ml (crystalloids). This signified a trend toward lower total volume of resuscitation (remember that 30 ml/kg recommendation)
•    The 2024 guidelines from Chest (REF 2) suggested that: “In Critically ill adult patients (excluding patients with thermal injuries and ARDS), intravenous albumin is not suggested for first line volume replacement or to increase serum albumin levels. Therefore, we should not give patients (except for cirrhosis or spontaneous bacterial peritonitis) albumin just to reduce the volume of fluid.
•    The authors suggested that even a definitive trial in the future will not be able to demonstrate a significant benefit of using 5% albumin.
Conclusion
There is lower mortality (numerical but not statistically) among the group with balanced crystalloids.

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Category: Critical Care

Title: Pearls for Ventilation During CPR

Posted: 9/24/2024 by Caleb Chan, MD (Updated: 10/9/2024)
Click here to contact Caleb Chan, MD

Some points from this narrative review:

  • much of the existing literature is based on animal models or small human studies
  • successful ventilations per compression pause (“synchronous" ventilation, 30:2, without advanced airway) is unsurprisingly important for neurologically intact survival
  • no clear difference in outcomes between “synchronous” vs. “asynchronous” (insufflation without pause in CPR) ventilation
  • RR below 6 breaths per min were associated with decreased ROSC, whereas faster RR were not associated with worse outcomes (however, be cautious of breathstacking in pts with asthma/COPD)
  • chest rise can be detected with TVs as low as 180 mL which is likely not sufficient for CPR
  • the benefit of larger tidal volumes (improved oxygenation, less hypercapnia) may outweigh the perceived costs (gastric insufflation, impact on venous return/CO)

Take home pearls:

  • use 2-person BVM to ensure adequate TVs and aim for more than just minimal chest rise
  • err on the side of moderately larger TVs rather than smaller and moderately faster RR rather than slower (but be cautious in pts with asthma/COPD)

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I wanted to send out two websites curated in part by UMEM current and past faculty/residents/fellows which have a wealth of critical care lectures and resources:

Disclosure: *I am one of the webmasters for the STCMTCC, but have no affiliation with MCCP other than as an enthusiastic reader.



Category: Critical Care

Title: Should I tell the paramedic to intubate this out-of-hospital cardiac arrest patient?

Keywords: RSI, intubation, critical care, out of hospital cardiac arrest (PubMed Search)

Posted: 9/10/2024 by Mark Sutherland, MD
Click here to contact Mark Sutherland, MD

Airway management in the pre-hospital setting is a matter of much controversy, and overall I will defer to my EMS colleagues, but several previous studies have failed to show a benefit to endotracheal intubation in the field as opposed to alternate approaches like a supraglottic airway.  Another nod in this direction has recently come out, with Battaglini et al performing a post-hoc analysis of one of the larger studies in the history of cardiac arrest, TTM-2, looking specifically at outcomes stratified by pre-hospital airway management strategy.  

Do patients who undergo endotracheal intubation in the field do better than those who get a supraglottic airway?

No, they don't.  TTM-2 included 1900 patients, of whom 1702 had enough data to be included in this re-analysis.  28% got supraglottic airways, and 72% got endotracheal intubation.  The groups were reasonably well matched on most characteristics, and if anything most well-known prognostic factors favored the endotracheal intubation group (very slightly).  It should be noted that several outcome metrics, including modified Rankin scale, did show slight signs of benefit for the endotracheal intubation group, even sometimes in a statistically significant fashion, but fell out when a multi-regression analysis, which was the primary endpoint, was done.  

Bottom Line: In pre-hospital cardiac arrest, there remains limited data to support the notion that endotracheal intubation results in better outcomes than supraglottic airway placement.  You should defer to your local protocols and continue to work with your paramedics and EMS directors as evidence continues to evolve.  For now, I don't think there's sufficient data to suggest that a given patient should be intubated vs undergoing supraglottic airway placement, and it is probably best to defer to the judgement, training, and protocols of your folks on scene.

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Category: Critical Care

Title: Naloxone Administration in Out-of-Hospital Cardiac Arrest

Keywords: OHCA, opioid, opiates, fentanyl, overdose, cardiac arrest (PubMed Search)

Posted: 9/2/2024 by Kami Windsor, MD
Click here to contact Kami Windsor, MD

Question

The incidence of opioid-overdose-related deaths has clearly increased in the past decade, with recent estimates of up to 17% of OHCA being opioid-related in 2023. [1,2] The use of naloxone for opiate reversal in overdose is well-established, with reasonable inference but no formal proof that its use could help in opioid-associated out of hospital cardiac arrest (OA-OHCA). [3] The August publication of two trials [4,5] retrospectively examining naloxone administration in OHCA offers some perspectives…

  • Patients receiving naloxone for OHCA are:
    • More often be younger, with fewer comorbidities, but more often unwitnessed than their non-naloxoned counterparts
    • More likely to have opioid OD as a presumed etiology

and

  • Naloxone administration is associated with:
    • Increased rates/odds of ROSC and survival to hospital discharge, whether OD is suspected or not
    • And “early” naloxone (given prior to EMS IV/IO access) is associated with increased rates of DC with good neuro outcome in PEA compared to receipt after IV/IO access or none at all

[View “Visual Diagnosis” for slightly more detail on the referenced studies.]

Bottom Line: While prospective trials are absolutely needed to offer more definitive evidence regarding the use of empiric naloxone in nontraumatic OHCA, the rising incidence of OA-OHCA in the U.S. and current findings are convincing enough to encourage early naloxone administration, especially in populations with higher incidence of opioid use.

U.S. Mortality due to Opioid Overdose (CDC data)

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Hepatorenal Syndrome

  • Emergency physicians evaluate patients with cirrhosis and ascites daily.
  • Patients with cirrhosis are particularly susceptible to acute kidney injury (AKI), which is associated with a significant increase in hospital mortality.
  • Hepatorenal syndrome (HRS) is a specific type of renal dysfunction in patients with cirrhosis and ascites.
  • The previous classification of HRS (Type 1, Type 2) has now been replaced by HRS-AKI, HRS-AKD, and HRS-CKD.
  • The diagnostic criteria for HRS-AKI include:
    • Increase in creatinine 0.3 mg/dL within 48 hrs or 50% from baseline value within the prior 7 days
    • Lack of improvement in creatinine or urine output within 24 hrs of adequate volume resuscitation
    • Absence of an alternative explanation for AKI
  • Management of HRS-AKI centers on accurate volume assessment, timely administration of a splanchnic vasoconstrictor (norepinephrine), administration of 20-25% albumin, and avoidance of additional nephrotoxins.

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Euglycemic DKA (eDKA) is a medical emergency requiring prompt attention. It is caused by an imbalance of insulin and glucagon leading to ketone accumulation (1-3). In addition to typical risk factors for DKA, those for eDKA include SGLT-2 inhibitor use and pregnancy, with 30% of DKA cases in pregnancy presenting euglycemic (4, 5).

eDKA presents with an anion gap metabolic acidosis, ketosis/ketonuria, & blood glucose less than 250 mg/dL.

Diagnosis requires ruling out other causes of anion gap metabolic acidosis, including toxic ingestions.

The cornerstone of eDKA management is ensuring enough dextrose to allow needed insulin administration to reverse ketone accumulation.

Pitfalls

  • Not giving enough insulin to reverse ketosis due to concern about low blood sugars
  • Not giving enough dextrose to support sufficient insulin dosing
  • Not uptitrating insulin for refractory acidosis caused by eDKA

Pearls

  • Start insulin with at least 0.05 units/kg/hour along with IV dextrose (3,5,7,9)
  • Start IV dextrose at 5-10 g/hr (9). This will be 100-200 mL/hr of a 5% dextrose solution (dextrose should be added to either normal or ½ normal saline to avoid causing hyponatremia!)
    • Dextrose concentrations: D5 = 50 g/L || D10 = 100 g/L || D20 = 200 g/L
  • Euglycemic DKA may present WITHOUT ketonuria if the patient is on an SGLT-2 inhibitor (7,8) – send a beta hydroxybutyrate!
  • eDKA is most common in the first two months of SGLT-2 inhibitor use, but can happen at any time (6)

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Diabetic ketoacidosis (DKA) is a serious condition that carries the risk of significant morbidity and mortality if not managed appropriately. Typically managed with an infusion of regular insulin, IV fluids, and electrolytes, there is evidence to support treatment of mild to moderate DKA with a subcutaneous (SQ) regimen using a combo of fast-acting and long-acting insulin instead, decreasing the need for ICU admission without increasing adverse events [1].  

What patients? 

  • Isolated DKA without other ICU requirements 
  • Mild-moderate severity as described below [2].

Adapted from Abbas et al. 

How to manage? 

  • These patients still require aggressive fluid replacement, frequent POC & BMP monitoring, aggressive electrolyte repletion and treatment of any underlying precipitating cause for their DKA.   
  • Insulin dosing should not be started until adequate electrolyte repletion has occurred. 
  • There is no universally-accepted protocol and several exist [1-4].   A reasonable approach:

Initial dose 

  • Insulin long-acting (glargine) 0.2 to 0.3 units/kg SQ or patient’s home dose 
  • Insulin fast-acting (aspart/lispro) 0.3 units/kg SQ

Subsequent dosing: 

If serum glucose is > 250 mg/dL 

  • Insulin short-acting 0.2 units/kg every 2 -4 hours

If serum glucose is < 250 mg/dL 

  • Insulin short-acting 0.1 units/kg every 2 – 4 hours OR SSI every 4 hours

Bottom Line 

DKA management with a SQ insulin protocol is a reasonable approach for patients with mild to moderate DKA, is supported by the American Diabetes Association [5], and can be particularly helpful in this era of ED boarding and bed shortages.  Give a long-acting insulin dose every 24 hours (or restart the patient’s home long-acting regimen) and short-acting insulin every 2 to 4 hours.  Aggressive IV fluid resuscitation, electrolyte repletion, and treatment of underlying precipitating cause remain additional cornerstones of DKA management.

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Category: Critical Care

Title: Do we keep Meropenem running? Or we give it every 8 hours?

Keywords: meropenem, continuous administration, critically ill (PubMed Search)

Posted: 8/6/2024 by Quincy Tran, MD, PhD (Updated: 10/9/2024)
Click here to contact Quincy Tran, MD, PhD

We heard it before. Continuous administration of antibiotics might be associated with better outcomes. However, results from smaller randomized controlled trials of beta-lactam showed inconsistent conclusions. Therefore, a large RCT was conducted

Settings: 31 ICUs in Croatia, Italy, Kazakhstan, Russia between June 2018 – August 2022.

Randomized, double-blind control trial.

Participants:

  • Patients with sepsis or septic shock who were given meropenem by their clinicians. 
  • A total of 607 patients were enrolled: 303 continuous meropenem vs. 304 intermittent administration of meropenem.

Outcome measurement

  • Primary outcome: all cause mortality at day 28.
  • Secondary outcome: emergency of pan-drug resistant bacteria at day 28.

Study Results:

  • 369 (61%) had septic shock, while 33% had low respiratory tract infection. There were 442 (73%) had invasive mechanical ventilation. 
  • Median SOFA score was 9 [6-11]; the median daily meropenem dose was 0.04 g/kg/day (total of 3 g/day).
  • The all cause mortality at 28 days was 91 (30%) for continuous group vs. 99 (33%) (P = 0.50) for intermittent group.
  • The rate of emergence of pandrug resistant bacteria was 68/288 (24%) vs. 70/280 (25%) (P= 0.70)

Discussion:

  • The current study involved more high risk patients, as the median SOFA was high at 9
  • There was no therapeutic monitoring in this study, so the minimal inhibitory concentration was not known.
  • Continuous meropenem might be less labor-intensive than intermittent meropenem, which required administration every 8 hours.

Conclusion

In critically ill patients with sepsis, continuous administration of meropenem did not improve mortality nor reduce the emergence of pandrug resistant bacteria.

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Do Sepsis Alert Systems Work?

Researchers in Korea completed a high quality systematic review and meta-analysis of sepsis alert systems for adult ED patients

Using high quality methods, they identified over 3000 studies with 22 meeting criteria. 

They found these systems were associated with:

  • reduced mortality risk (risk ratio [RR], 0.81; 95% CI, 0.71 to 0.91)
  • length of hospital stay (standardized mean difference, ?0.15; 95% CI, ?0.20 to ?0.11)
  • Better adherence to sepsis bundle elements:
    • shorter time to fluid administration (SMD, ?0.42; 95% CI, ?0.52 to ?0.32), 
    • blood culture (SMD, ?0.31; 95% CI, ?0.40 to ?0.21)
    • antibiotic administration (SMD, ?0.34; 95% CI, ?0.39 to ?0.29)
    • lactate measurement (SMD, ?0.15; 95% CI, ?0.22 to ?0.08)

Electronic alerts were further associated with:

  • reduced mortality (RR, 0.78; 95% CI, 0.67 to 0.92)
  • adherence with blood culture guidelines (RR, 1.14; 95% CI, 1.03 to 1.27).

Summary (+ a little editorialization)

As annoying as we may find these systems in our daily practice, there is growing evidence that they do provide some benefit with impacts on task saturation and decreasing cognitive load in addition to real patient benefit. While there is also recent evidence that physician gestalt performs well against these systems, there is a suggested benefit in their inclusion in clinical decision making as a safety net or as an “assist”.

The incorporation of rule-based algorithms like these in more advance machine learning methods are covered quite well in a recent opinion piece on “The AI Future of Emergency Medicine”. However, it is important to always know the source of any “algorithm” that you are using, whether rule or mathematically based, given real concerns for bias and error.

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The CLOVERS trial (NEJM 2023) examined one of the eternal questions of critical care, liberal vs restrictive fluid management in sepsis… and found no difference.  But there are criticism of CLOVERS, and while some other trials agreed with this result, there are also signals in the literature that restrictive fluid strategies are beneficial.  Furthermore, we know that these trials suffer from issues of  heterogeneity, and often lump together very different patients.

Jorda et al recently published in Critical Care a posthoc re-analysis of CLOVERS looking specifically at patients with advanced CKD (eGFR < 30).  This is a challenging group of patients to manage.  On the one hand their renal function is already marginal, so the last thing we want to do is potentially deprive starved kidneys of necessary intravascular volume, but on the flip side their septic shock puts them at high risk of full blown renal failure (transient or permanent) and they're thus at very high risk of fluid overload with aggressive resuscitative fluids and potentially limited ability to clear those fluids renally in the next few days.  So how did these patients do in CLOVERS?

They did significantly better with the restrictive fluid strategy (mortality 22% vs 39%, HR CI 0.29-0.85).  They also had more pressor free days and vent free days.  

Bottom Line (my opinion): While a restrictive vs liberal fluid strategy in septic shock remains a bit up for debate, the evidence continues to slowly tip towards restrictive fluids (i.e. earlier pressors) as the preferred approach.  In patients with advanced CKD (eGFR < 30), there is probably now sufficient evidence to favor vasopressors over IV fluid administration when resuscitating septic shock.

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Category: Critical Care

Title: Steroids in the Critically Ill

Keywords: Corticosteroids, septic shock, ARDS, acute respiratory distress syndrome, community acquired pneumonia, CAP, dexamethasone, methylprednisolone, hydrocortisone (PubMed Search)

Posted: 7/9/2024 by Kami Windsor, MD
Click here to contact Kami Windsor, MD

This May, the Society of Critical Care Medicine (SCCM) published new recommendations [1] for the use of corticosteroids in critical illness (separate from patients with known adrenal insufficiency or on chronic steroids), namely:

  1. “Suggesting” for all septic shock with continued vasopressor requirement not just “refractory” (requiring 2+ pressors) 
    • Matches the 2021 Surviving Sepsis Campaign Guidelines suggestion [2]
  2. “Suggesting” for ARDS (acute onset, bilateral infiltrates not due to cardiac dysfunction or volume overload, PaO2: FiO2 </= 300)
    • Matches the 2024 American Thoracic Society Clinical Practice Guidelines suggestion [3]
    • Does not explicitly exclude influenza+ ARDS, in which steroids have previously been associated with worsened outcomes [4]
  3. “Recommending” for patients with bacterial community acquired pneumonia and new O2 requirement
    • New guidelines from ATS/IDSA not yet updated from 2019; support primarily from 2023 CAPE COD trial [5]

Bottom Line:

For severe bacterial pneumonia and septic shock, ED physicians should feel comfortable administering a dose of hydrocortisone 50mg IV as hydrocortisone 200mg/day is an accepted regimen for these disease processes. 

For patients with ARDS who remain boarding in the ED, EM docs should discuss initiation of steroids with their intensivists, whether the institutional preference is for dexamethasone 20mg IV (per DEXA-ARDS) [6] or methylprednisolone 1mg/kg/day (per Meduri)[7].

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Noninvasive Ventilation for Preoxygenation

  • Over 1 million critically ill patients are intubated each year in the United States.
  • Hypoxemia can occur in up to 20% of intubations and may lead to adverse outcomes such as peri-intubation cardiovascular collapse or cardiac arrest.
  • Appropriate preoxygenation is critical to increase the safe apnea time and decrease the risk of hypoxemia during rapid sequence intubation (RSI).
  • At present, the majority of critically ill patients undergoing RSI are preoxygenated with an oxygen mask.
  • In a randomized, pragmatic, parallel-group trial conducted in 7 EDs and 15 ICUs in the United States, Gibbs et al compared the use of noninvasive ventilation for preoxygenation to an oxygen mask on the incidence of hypoxemia during intubation.
  • In over 1,300 patients, the incidence of hypoxemia during the interval between induction and 2 minutes after intubation was markedly lower in patients preoxygenated with noninvasive ventilation compared to those preoxygenation with an oxygen mask.
  • Importantly, the greatest benefit to noninvasive ventilation for preoxygenation was seen in patients with acute hypoxemic respiratory failure, those requiring > 70% FiO2 prior to intubation, and those with a BMI > 30.
  • Lastly, the trial did not enroll patients who needed emergent intubation without time for at least 3 minutes of preoxygenation.

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Category: Critical Care

Title: Recognizing Sepsis: Man versus Machines

Keywords: sepsis, septic shock, warning scores (PubMed Search)

Posted: 6/25/2024 by Kami Windsor, MD (Updated: 10/9/2024)
Click here to contact Kami Windsor, MD

Background: Sepsis remains a common entity associated with a relatively high rate of inpatient mortality, with timely recognition and treatment being key to improving patient outcomes. Various screening and warning scores have been created to attempt to identify sepsis and those patients at high risk of mortality earlier, but have limited performance because of suboptimal sensitivity and specificity.

A prospective observational study compared the performance of a variety of these scores (SIRS, qSOFA, SOFA, MEWS) as well as a machine learning model (MLM) against ED physician gestalt in diagnosing sepsis within the first 15 minutes of ED arrival. 

  • 2550 patients deemed by EMS or triage nurse as potentially critically-ill
    • Excluded trauma, cardiac arrest, acute MI, stroke activation, patients in labor
  • Seen by ED attendings (94%) / senior residents (6%) at a single urban academic center
    • Visual analog scale assessment, 0-100% likelihood that patient has sepsis
    • VAS >50% treated as ED physician gestalt in favor of sepsis
  • 275 patients ultimately with discharge diagnosis of sepsis present on arrival to hospital
  • Initial VAS outperformed all scores (AUC 0.90; 95% CI 0.88 to 0.92) both at 15 minutes and 1 hour

Although not without its limitations, this study highlights the importance and relative accuracy of physician gestalt in recognizing sepsis, with implications for how to develop future screening tools and limit unnecessary exposure to unnecessary fluids and empiric broad spectrum antibiotics.

Bottom Line: In the era of machine learning models and AI, ED physicians are not obsolete. Even at 15 minutes, without lab results and diagnostics, our assessments lead to appropriate diagnoses and care. In this new normal of prolonged wait times and ED boarding, ED triage and evaluation models that optimize early physician assessment are of the utmost importance.

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Category: Critical Care

Title: Magnesium for RSI?

Keywords: RSI, intubation, magnesium (PubMed Search)

Posted: 6/18/2024 by Mark Sutherland, MD
Click here to contact Mark Sutherland, MD

Magnesium is known to relax smooth muscles.  Interestingly, there is also some literature using it as part of Rapid Sequence Intubation (RSI) pre-treatment in general, in hopes that this or other mechanisms might allow it to improve intubating conditions.  Zouche et al recently published an RCT looking at giving IV magnesium as part of RSI pretreatment in cases where neuromuscular blockade (NMB) is not going to be given (e.g. scenarios where it is contraindicated).  IV Magnesium Sulfate, 50 mg/kg in 100 mL of saline given 15 minutes before induction, significantly improved intubating conditions in those getting sedation but not NMB (95% vs 39%).  

In 2013, Park et al did an RCT giving magnesium to all RSIs, even with the use of rocuronium in those patients, arguing that magnesium is also known to potentiate the effects of non-depolarizing NMB agents.  They also found better intubating conditions in the magnesium patients.

In both trials, magnesium was associated with lower heart rates and less hypertension in the peri-intubation and immediate post-intubation periods (of note: high dose magnesium is known to be associated with lower blood pressures, and can induce overt hypotension).  Neither study was really powered for more important measures like first pass success, mortality, or important side effects like peri-intubation hypotension.

Bottom Line: These are two small trials, and while more abundant literature should probably be obtained before we change our practice, one could consider giving magnesium sulfate, 50 mg/kg in 100 mL saline, prior to intubation in an attempt to improve intubating conditions.  In my opinion, this is probably worth considering in the rare circumstance that your patient has a true contraindication to neuromuscular blockade, but I probably wouldn't start doing this in standard RSI where you're going to be giving NMB until more literature confirms the safety of this approach.  Also, I would avoid this in situations where the patient is already hypotensive or at high risk of peri-intubation hypotension.  This may be worth considering in the very rare patient you're not necessarily going to give NMB to right away (maybe awake fiberoptic intubations?) who are also very low risk for hypotension.

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Title: Antipsychotics in the Treatment of Delirium in Critically Ill Patients: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

We all do it. When our patients in the ICU develop delirium, we would give them an antipsychotic, commonly quetiapine (Brand name Seroquel), and all is good. However, results from this most recent meta-analysis may suggest otherwise. 

Settings: This is a meta-analysis from 5 Randomized Control Trials. Intervention was antipsychotic vs. placebo or just standard of care.

Participants: The 5 trials included A total of 1750 participants. All trials used Confusion Assessment Method for the ICU or Intensive Care Delirium Screening Checklist to measure delirium.

Outcome measurement: Delirium – and Coma-Free days

Study Results:

The use of any antipsychotic (typical or atypical) did not result in a statistically significant difference in delirium- and coma-free days among patients with ICU delirium (Mean Difference of 0.9 day; 95% CI -0.32 to 2.12).

![A close-up of a graph

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Similarly, atypical antipsychotic medication also did not result in difference of delirium- and coma-free days: Mean difference of 0.56 day; 95% CI -0.85 to 1.97).

![A white sheet with numbers and symbols

Description automatically generated with medium confidence](https://umem.org/files/uploads/content/pearls/image-66717a4dadd96.png)

ICU length of stay was also not different in the group receiving antipsychotic: Mean difference -0.47 day, 95% CI -1.89 to 0.95).

![A close-up of a graph

Description automatically generated](https://umem.org/files/uploads/content/pearls/image-66717a4dcdf2f.png)

Discussion:

The authors used both delirium -free and coma-free days as a composite outcome because they reasoned that delirium cannot be evaluated in unresponsive patients. This composite outcome might have affected the true incidence of delirium and the outcome of delirium-free days. 

This meta-analysis would be different from previous ones that aimed to answer the same question. Previous studies compared either haloperidol vs a broader range of other medication (atypical antipsychotic, benzodiazepines) (Reference 2) or included all ICU patients  with or without delirium who received haloperidol vs. placebo (Reference 3). Overall, those previous studies also reported that the use of haloperidol has not resulted in improvement of delirium-free days.

Conclusion

There is evidence that the use of anti-psychotic medication does not result in difference of delirium- or coma-free days among critically ill patients with delirium.

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Many patients present to the ED with hypercarbic respiratory failure (i.e. COPD exacerbation, obesity hypoventilation syndrome etc.). Typically, our first line of treatment is the use of BiPAP, where we set an inspiratory pressure (IPAP) and an expiratory pressure (EPAP). The difference between these two pressures (as well as patient effort) determines the tidal volumes (and consequently minute ventilation) a patient receives in our attempts to help the patient “blow off CO2.” 

If you are having trouble with continued hypercarbia despite the use of BiPAP, another NIPPV mode that can be trialed is Average Volume-Assured Pressure Support (AVAPS). With BiPAP the patient receives the same fixed IPAP no matter what, even if their tidal volumes are lower than what is needed. With AVAPS, the ventilator will self-titrate the IPAP and increase (or decrease) the IPAP to reach the tidal volumes that you set, increasing the odds the patient will achieve the minute ventilation you are trying to achieve.

(AVAPS is essentially a non-invasive version of PRVC)

Initial settings (ask your RTs for help!):

  • The target tidal volume is set to 8 ml/kg of ideal weight 
  • The maximal IPAP value is generally fixed at 20-25 cm H2O
  • The minimal IPAP value equals to EPAP + 4 cm H2O
  • The value of the minimal inspiratory pressure is no less than 8 cmH2O and commonly higher
  • The respiratory rate is set at 2-3 BPM below the resting respiratory rate

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This really interesting study suggests that the classic site of CPR “in the middle of the chest” may actually not be the ideal place to perform CPR. Previous imaging studies demonstrate that the ventricles are primarily beneath the lower third of the sternum and that standard placement of CPR compressions may deform the aortic valve, blocking the LVOT, and theoretically limiting perfusion of the coronaries and brain.

This study compared a standard CPR group with those undergoing TEE-guided chest compressions to avoid aortic valve compression. Those in the non-AV compression group had significantly increased likelihood of ROSC, survival to ICU, and higher femoral arterial diastolic pressures. However, there was no difference in long-term outcomes or end-tidal CO2.

Summary: Avoiding AV compression during CPR significantly improved the chance at ROSC in adult OHCA, but this small observational study did not show any difference in long term outcomes when compared to standard practice. Lowering the point of chest compressions in CPR to the lower third of the sternum may be beneficial.

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Historically, guideline recommendations have been to use a transfusion threshold of hemoglobin < 7 g/dL for patients unless they are a) undergoing orthopedic surgery or b) have cardiovascular disease (CVD).  

Applefeld et al conducted a meta-analysis in 2018 which suggested that restrictive (i.e. lower hemoglobin trigger, typically 7-8) transfusion targets lead to worse outcomes in CVD patients than liberal (i.e. higher hemoglobin trigger, typically 9-10) targets, and those authors have updated this analysis to include data from newer trials.  Interestingly, the conclusion remains similar: that when you look at the larger studies on restrictive vs liberal transfusion targets, CVD plays an important role, as patients with CVD tend to do better with liberal targets, and patients without CVD tend to do better with restrictive targets.  Of note, CVD is variably defined in these studies, and sometimes limited only to active Acute Coronary Syndromes, and other times refers to all patients with acute or chronic CVD.  However, according to their analysis, the aggregated data suggests that we should continue having higher transfusion targets in patients with CVD, and perhaps even more in the 9-10 range, as opposed to the goals of 7 or 8 which are common.

Bottom Line: We will likely continue to see different transfusion targets recommended for patients with cardiovascular disease (CVD), and may even see guideline and blood bank recommendations raise the target for these patients more into the 9-10 range, or expand this group to include chronic CVD.  This would mean a substantial increase in recommended RBC transfusions, and as emergency physicians it is important for us to monitor these recommendations, especially since transfusions are not harmless and raising hemoglobin thresholds could lead to complications that are difficult to measure in the literature.

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