Hypothermia and Drowning Pearls

Author: Ryan Pedigo, MD (Chief Resident and PGY-3, Harbor-UCLA Medical Center – @DrPedigo) // Editors: Manpreet Singh, MD (@MPrizzleER) and Alex Koyfman, MD (@EMHighAK)

Accidental Hypothermia Pearls

  • Hypothermia is a core temperature less than 35 degrees Celsius

Hypothermic patients without vital signs

Should resuscitation be initiated?
  • Must decide if they arrested and then got cold, or arrested because they were cold
  • If arrested because they were cold, CPR duration does not predict outcome
    • Case report of 190 minutes of CPR with full neurologic recovery – cold is protective!
  • In general, a cardiac arrest from hypothermia requires a temperature under 32°C
  • Potassium greater than 12 mEq/L is criteria for terminating resuscitation
  • If patient’s chest is frozen solid and chest is not compressible, do not resuscitate
Did they have a drowning incident? Was it submersion or immersion?
  • Submersion: Patient goes under water immediately, becomes hypoxemic, arrests and cools
    • Extremely poor prognosis except perhaps in pediatric patients who can cool faster
  • Immersion: Patient is in the water but able to breathe, arrests due to hypothermia only
    • Prognosis is good

Resuscitation pearls (NEJM Accidental Hypothermia 11/2012)

  • Follow management flowchart (see below)
  • Warm fluids to prevent further heat loss; cold diuresis may mean high fluid requirements
  • Rescue collapse: Cardiac arrest related to extrication / transport of a cold patient
    • Minimize patient movement if still has a pulse
  • Afterdrop: Continued core cooling during rewarming – physiologically-real but clinically insignificant
  • Always consider ECMO and transfer, knowing that CPR duration / transport time is not predictive of outcome
    • ECMO center survival rate: 50% (note: selection bias likely contributes to this)
    • Non-ECMO center survival rate: 10%
  • European Resuscitation Council recommendations
    • Up to 3 defibrillations until T > 30°C (then as normal)
    • No epinephrine until T > 30°C, only half as frequent epinephrine until T > 35°C
    • ACLS on epinephrine in hypothermia: “may be reasonable to consider”


Hypothermic patients with vital signs

  • Hypothermia with cardiac instability: ECMO transfer
    • Consider bladder lavage but need to do esophageal temperature measurements
    • Consider thoracic or peritoneal lavage if cannot transfer to ECMO center
  • Hypothermia with stable vital signs
    • Warm with warm fluids, Bair Hugger, warm room
  • If patient becomes unstable, #1 intervention is high-quality CPR

Drowning Pearls

  • Definition: Drowning is a process resulting in primary respiratory impairment from submersion/immersion in a liquid medium. Implicit in this definition is that a liquid/air interface is present at the entrance of the victim’s airway, preventing the victim from breathing air. The victim may live or die after this process, but whatever the outcome, he or she has been involved in a drowning incident.
  • Nomenclature: Reading the above definition indicates that all patients involved in a drowning incident have drowned, regardless of patient outcome. The terms “dry”, “wet”, “active”, “silent”, “secondary”, and “near-drowning” should not be used (consensus statement, 2003 Circulation).


  • Breath holding underwater > involuntary gasp > aspiration/laryngospasm > LOC > active aspiration > death
  • 90% “wet drowning” and 10% “dry drowning”
  • Aspiration leads to loss of surfactant, atelectasis, V/Q mismatch, and ARDS
  • Hypoxemia leads to a significant metabolic acidosis


  • No prophylactic antibiotics (consider if drowned in obviously infected source such as sewage tank)
  • C-spine immobilization only if high concern for injury (injuries only occur in 0.5% of drowning)




Brown DJ et al. N Engl J Med 2012;367:1930-1938. Management and Transport in Accidental Hypothermia.

Szpilman D et al. N Engl J Med 2012;366:2102-2110. Treatment of Persons Who Have Drowned.

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April 2015 REBELCast

REBELCastWelcome to the April 2015 REBELCast, where Swami, Matt, and I are going to tackle a couple of articles just published this year. Today we are going to specifically tackle:

  • Topic #1: Basic Life Support (BLS) vs Advanced Cardiac Life Support (ACLS) in Out of Hospital Cardiac Arrest (OHCA)
  • Topic #2: PROMISE Trial – Anatomic vs Functional Testing for Coronary Artery Disease (CAD)

April 2015 REBELCast Podcast

Click here for Direct Download of Podcast

What clinical questions will be covered in the April 2015 REBELCast?

  • Question #1: Does Advanced Cardiac Life Support (ACLS) or Basic Life Support (BLS) have larger beneficial effects on outcomes for Out of Hospital Cardiac Arrest (OHCA)?
  • Question #2: Does anatomic testing with coronary computed tomographic angiography (CCTA) result in improved health outcomes over functional testing in symptomatic patients with suspected CAD?


What specific articles will we be covering?

  • Article #1: Saghavi P et al. Outcomes After Out-of-Hospital Cardiac Arrest Treated by Basic vs Advanced Life Support. JAMA Intern Med 2015; 175 (2): 196 – 204 [1]
  • Article #2: Douglas PS et al. Outcomes of Anatomic versus Functional Testing for Coronary Artery Disease. NEJM 2015 [epub ahead of print] [2]


What is the clinical bottom line for the above clinical questions:

  • Bottom Line #1: Patients with OHCA who receive BLS have a higher survival to hospital discharge, survival to 90days, and more have better neurologic functioning vs patients who receive ACLS
  • Bottom Line #2: An initial strategy of using CCTA for noninvasive testing in symptomatic patients with suspected CAD is not associated with better clinical outcomes compared to functional testing over median follow-up of two years. It was, however, associated with higher radiation exposure and downstream testing.

March 2015 REBELCast Show Notes

Word Document: REBELCast April 2015 Show Notes
PDF: REBELCast April 2015 Show Notes

For more on the above topics checkout:




  1. P. Sanghavi, A.B. Jena, J.P. Newhouse, and A.M. Zaslavsky, "Outcomes after out-of-hospital cardiac arrest treated by basic vs advanced life support.", JAMA internal medicine, 2015. http://www.ncbi.nlm.nih.gov/pubmed/25419698
  2. P.S. Douglas, U. Hoffmann, M.R. Patel, D.B. Mark, H.R. Al-Khalidi, B. Cavanaugh, J. Cole, R.J. Dolor, C.B. Fordyce, M. Huang, M.A. Khan, A.S. Kosinski, M.W. Krucoff, V. Malhotra, M.H. Picard, J.E. Udelson, E.J. Velazquez, E. Yow, L.S. Cooper, K.L. Lee, and . , "Outcomes of anatomical versus functional testing for coronary artery disease.", The New England journal of medicine, 2015. http://www.ncbi.nlm.nih.gov/pubmed/25773919

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Ultrasound For The Win Case – 46F with Abdominal Pain #US4TW

Ultrasound-For-The-WinWelcome to another ultrasound-based case, part of the “Ultrasound For The Win” (#US4TW) Case Series. In this peer-reviewed case series, we focus on real clinical cases where bedside ultrasound changed management or aided in diagnoses. In this case, a 46-year-old woman presents with history of right-sided abdominal pain and vomiting.

Case Presentation

A 46-year-old obese woman presents to the ED with three hours of non-bilious emesis and right-sided abdominal pain. She has been unable to eat secondary to pain. On examination, she appears in moderate distress, and has diffuse abdominal tenderness to palpation, worst at the right upper quadrant without rebound or guarding.


BP 127/77 mmHg
P 112 bpm
RR 20 breaths/min
O2 99% room air
T 36.6 C

Differential Diagnoses

  • Appendicitis
  • Cholangitis
  • Cholelithiasis
  • Cholecystitis
  • Choledocolithiasis
  • Gastritits
  • Pancreatic mass
  • Pancreatitis
  • Peptic ulcer disease
  • Pregnancy
  • Viral syndrome

Initial Workup

Computed tomography (CT) of the abdomen and pelvis with intravenous (IV) contrast was obtained and the radiology report was read as normal.


  • White blood cells: 10.4 cell/hpf
  • Total bilirubin: 1.6 mg/dL
  • Direct bilirubin: 1.2 mg/dL
  • Alkaline phosphatase: 274 U/L
  • Alanine aminotransferase (ALT): 464 IU/L
  • Aspartate aminotransferase (AST): 447 IU/L
  • Urinalysis: Negative for pregnancy, leukocytes, nitrites, white blood cells, and red blood cells

Given the ongoing concern for potential gallbladder pathology, a point-of-care ultrasound was performed.

POINT-OF-CARE ULTRASOUND was performed which showed the following:

Image 1. Point-of-care ultrasound of the gallbladder shows a large stone in the gallbladder neck (Stone-in-Neck sign), concerning for acute cholecystitis.

Image 2. The Stone-in-Neck sign: An immobile hyperechoic stone (blue arrow) seen in the gallbladder neck with posterior shadowing (#)

The images in this case demonstrate a stone lodged in the neck of the gallbladder – also known as the “Stone-in-Neck” sign [1]. A large hyperechoic stone is seen with posterior shadowing. Rolling the patient to left and right lateral positions may be necessary to distinguish between a mobile versus a non-mobile stone in the neck. A SIN sign is highly suggestive of cholecystitis, and has been found to be 97% specific [1].

Ultrasound Image Quality Assurance (QA)

Point-of-care ultrasonography of the gallbladder is one of the more challenging bedside studies to perform. This study is ideally performed with the curvilinear probe; the lower frequency of this probe allows for greater penetration that can be helpful, especially in obese patients. There are a few ways to identify the gallbladder; one way is to start in a sagittal plane at the subxiphoid and slide the probe inferiorly and to the patient’s right just below the costal margin. Another technique is to start at the mid-axillary line on the patient’s right side in a coronal orientation, similar to a FAST study. Having the patient take a breath in and holding it, or turning them onto their left lateral side may also optimize positioning to help to visualize the gallbladder.

Once visualized, the gallbladder anatomy should be identified including the fundus, body, and neck. As is the case with most point-of-care ultrasounds, you should obtain images in two planes to avoid missing potential pathology. The main lobar fissure (MLF), seen as a bright hyperechoic line, is a landmark that allows for identification of the portal triad, and together has the appearance of an exclamation point.

Image 3. Landmarks for the gallbladder (GB) include the main lobar fissure (blue arrow) which extends from the GB to the portal triad (*)

The next step is to visualize potential gallbladder pathology including cholelithiasis or acute cholecystitis.

The 4 sonographic signs of cholecystitis are:

  1. Gallstones/sludge – Visualized as hyperechoic structures within the gallbladder with posterior shadowing
  2. Thickened gallbladder wall – Greater than 4 mm. Of note, the anterior, not posterior wall, should be measured to avoid overestimating of the wall due to artifacts off the posterior wall.
  3. Pericholecystic fluid – Seen as an anechoic stripe surrounding the gallbladder
  4. Sonographic Murphy Sign – There is a positive Murphy Sign when pressure placed on the visualized gallbladder with the ultrasound probe reproduces the pain.

Although all four signs are not needed to make a diagnosis of cholecystitis, the presence of all four signs is very specific for cholecystitis. Concurrently, each sign seen independently is non-specific and should be taken into context with the clinical scenario.

Image 4. Sonographic signs of acute cholecystitis. Gallbladder with a hyperechoic stone and wall thickening with pericholecystic fluid (blue arrow).

Disposition and Case Conclusion

General surgery was consulted given the concerning findings on ultrasound, and she was admitted to the hospital for further management.

Point-of-care ultrasonography of the right upper quadrant is an important skill for the emergency physician (EP) to have. The initial CT scan was read as negative, and if the EP had been falsely reassured by that and discharged the patient, it would have likely led to a bad outcome.

This case highlights the fact that ultrasonography is superior to CT for the evaluation of gallbladder pathology; while the CT scan revealed no evidence of cholelithiasis or cholecystitis, the point-of-care ultrasound revealed a large stone in the neck (“Stone-in-Neck sign”) which is highly suggestive for cholecystitis. Ultrasonography has been shown to be more sensitive for the identification of cholelithiasis and cholecystitis. CT imaging is 79.1% sensitive and 100% specific for cholelithiasis [2], compared with 88% sensitivity and 87% specificity with ED-performed point-of-care ultrasonography [3].

As radiology-performed ultrasound may be limited or unavailable at smaller community EDs, it is important for the EP to have the skills to identify acute cholecystitis on point-of-care ultrasound. EP-performed ultrasonography for the diagnosis of acute cholecystitis has been shown in a prospective study to be not significantly different from radiology-performed ultrasound (87% sensitive and 82% specific for ED ultrasound, compared with 83% sensitive and 86% specific for radiology ultrasound) using pathology specimens as the gold standard [4].

Take-Home Points

  1. Point-of-care ultrasonography of the right upper quadrant is an essential skill for the emergency physician. It is more sensitive than CT for evaluation of gallbladder pathology.
  2. Sonographic findings of cholecystitis include:
    • Gallstones/sludge
    • Thickened gallbladder wall
    • Pericholecystic fluid
    • Sonographic Murphy Sign
  3. The Stone-in-Neck sign, visualization of an immobile stone lodged in the neck of the gallbladder, is highly suggestive of acute cholecystitis, with 97% specificity [1].
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Expert Peer Review
Expert Peer Review

Author information

Jeffrey Shih, MD

Jeffrey Shih, MD

Assistant Editor, Ultrasound for the Win Series,

Academic Life in Emergency Medicine;

Emergency Ultrasound Fellow,
Instructor in Emergency Medicine,
Yale University School of Medicine

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