Intern Report 7.8

Case Presentation by Dr. Jessie Swan, MD

History of Present Illness:
A 62-year-old African American male  was brought to the Emergency Department by EMS after being found lying on the ground inside an abandoned house.  His friends had called EMS because he had been lying in the same spot for the past three days.  Per EMS there were no pill bottles or alcohol bottles around the patient.  The outdoor temperature  was in the 20s and EMS states that the house was not heated;  actually it felt colder inside the building than outdoors.  You  were unable to obtain any other history from the patient as he is only able to mumble incoherently.

Past Medical History (per EMR):

Social history (per EMR):
-Denied tobacco, alcohol or other drugs

Medication (per EMR):
-Norvasc 5mg daily

Physical Exam:
Vitals: BP 94/64, P 67, RR 14, T 28.4 °Celsius rectal, oxygen  saturation unable to obtain.
GENERAL:  He is lying in bed and  appeared  disheveled.  Dressed in only one layer of long underwear under jeans and a jacket.  He mumbled incoherently in response to stimuli.

HEAD:  Without evidence of trauma.

EYES:  Pupils are 3 mm, round and nonreactive to light bilaterally.

EARS, NOSE, MOUTH, AND THROAT:  Throat was clear.  Mucous membranes appear to be dry.

NECK:  Trachea midline.

RESPIRATORY:  Lungs revealed clear breath sounds bilaterally.

CARDIOVASCULAR:  The patient had a heart rate of 67 beats/minute and rhythm was regular.  He had faint palpable pulses in his wrist and feet bilaterally.

GASTROINTESTINAL:  Abdomen is soft, nondistended, nontender to palpation.  No palpable masses.

EXTREMITIES:  No edema.  He had cyanosis of his feet bilaterally.

SKIN:  Extremely cold to the touch without evidence of skin rash.  He had some previous signs of skin grafting and scarring in his right upper chest wall.

NEUROLOGIC:  He had spontaneous eye opening.  He did appear to follow some simple commands, He could not provide any further information.  Patient was not flaccid however was weak in the upper and lower extremities.  Localized to painful stimuli.

Labs / Imaging / ED course:
Na 132, K 3.8, Cl 86, Bicarb 5, BUN 58, Cr 3.09, Glucose 74, Anion gap 41
WBC 7.3, Hgb 13.5, Platelet 186, MCV 96.3
CPK 3932, Lactic Acid 10.9, Trop 0.247, EtOH 283

ABG: pH 6.84PCO2 19.0PO2 6.9HCO3 2.0

U/A neg

CXR: Patchy multifocal airspace opacities noted bilaterally concerning for multifocal pneumonia and/or aspiration pneumonia.

EKG: Difficult to interpret due to wavy baseline with pt shivering.  QTc was 599.
ECG 7.8

The patient was covered with warm blankets and fluid resuscitated with a total of warmed 3L 0.9% NS. A femoral central line was placed using a Zoll triple-lumen central line femoral vein catheter and central rewarming was initiated.  Patient was also started on Azithromycin and Ceftriaxone, given 2 Amps NaHCO3, and given a rectal aspirin.  He was admitted to the MICU.

1.  What is the acid/base disturbance?
a.  Primary: non anion gap metabolic acidosis. Secondary: respiratory alkalosis
b.  Primary: anion gap metabolic acidosis. Secondary: respiratory acidosis
c.  Primary: anion gap metabolic acidosis. Secondary: respiratory alkalosis
d.  Primary: non anion gap metabolic acidosis. Secondary: respiratory acidosis.

2.  All of the following are common physiologic EKG findings associated with hypothermia EXCEPT?
a.  Bradycardia
b.  Atrial fibrillation
c.  J waves
d.  Ventricular fibrillation

3.  Under what circumstance is further intervention generally considered futile?
a.  A potassium level >12mmol/L
b.  After 2 hours of CPR
c.  When the patient presents initially without signs of life and absent vital signs.
d.  When, after rescue and initial intervention, the patient’s core temperature continues to drop.

Answers & Discussion:
1. B
Primary metabolic acidosis, with increased anion gap, mixed with a metabolic alkalosis, with superimposed respiratory acidosis

First: pH is 6.84 which is an acidosis

Second: pCO2 is low at 19, Bicarb is low at 2.0 so this is a primary metabolic acidosis

Third: Winters Formula PCO2=1.5(HCO3)+8±2; PCO2=9to13; actual CO2 is higher at 19 so there is a secondary respiratory acidosis

Fourth: Anion Gap=Na-(Cl+HCO3); Anion Gap=41; the anion gap is >12 so this is an anion gap metabolic acidosis

EXTRA: Fifth: Delta Gap=(AG-12)-(24-HCO3); Delta Gap=10; the delta gap is >6 so this represents an anion gap metabolic acidosis with a mixed metabolic alkalosis.

2. D
A. At a core temperature of 28 degrees Celsius oxygen consumption and the pulse rate are usually decreased by 50%.

B. Atrial fibrillation is common when the core temperature is less than 32 degrees Celsius and is generally not worrisome in the absence of other signs of cardiac instability.  It rarely leads to a ventricular response.

C. J waves (Osborne waves) appear secondary to an exaggerated outward potassium current leading to a repolarization abnormality. These waves are detectable in 80% of the patients with a core body temperature lower than 30°C. J waves are seen in lead II and precordial leads V2-V6.

D. Ventricular findings are serious when seen in hypothermic patients.  Ventricular arrhythmias are very difficult to correct in these patients and often result in asystole.

3.  A
A.  A severely elevated serum potassium level is associated with nonsurvival.  It is an indication of hypoxia before cooling.  If the serum potassium level is higher than 12mmol/L termination of CPR should be considered.  The highest recorded levels of serum potassium in patients with hypothermia who were successfully resuscitated are 11.8 in children and 7.9 in adults.  At a level between 10 and 12 it is recommended that consideration of ECMO or CPB should be made. A level below 10 should prompt continued CPR until the patient is rewarmed as survival without neurologic impairment may be possible

B.  The longest reported duration of CPR in a hypothermic patient who subsequently achieved full neurologic recovery is 190 minutes in a patient receiving extracorporeal rewarming.

C.  Stage HT IV of the Swiss staging system is characterized by a core temperature of <24ºC with no vital signs.  In these patients appropriate treatment includes active external and minimally invasive rewarming techniques, airway management as required, ECMO or CPB if cardiac instability is refractory to medical management, plus CPR with up to three doses of epinephrine and defibrillation with further dosing guided by clinical response.

D.  A drop in temperature, indicating continued core cooling after rescue, is a documented phenomena.  This may also be the result of discrepancies between different methods of temperature measurement.