Emergency Medical Services (EMS) Agency


Case Presentation

Paramedics respond to the home of a 39 year-old female whose husband called 911 when he returned home from taking their older children ice skating  at the local rink and found her ill in bed.  He states that when he left home around 9 am she appeared normal.  When he returned at 2 pm he found her lying in bed covered in blankets, complaining of weakness and nausea.  She was at home with their 2 year old child who she put down for a nap.  She has no medical problems and takes no medications.  On paramedic arrival she is alert and oriented to person and place but not time and has difficulty answering questions.  She is unable to stand unassisted.  She has no facial droop or other focal neurological deficits.  Her vital signs are HR 110, BP 98/54, RR 22, O2 saturation 99% on RA.

The couple’s 2 year old son was found in bed when the husband returned home.  He is difficult to arouse.

The mother has an altered level of consciousness (ALOC) that has manifested acutely.  Initial management should focus on lifesaving interventions to include managing the patient’s airway if needed and attempting to determine an underlying cause, in particular causes that would respond to immediate field intervention.  The potential causes for ALOC are numerous and may be due to a serious medical condition.

The child is difficult to arouse with an altered level of consciousness as well.  A complete assessment needs to be performed on the child.

Initial management can begin for the mother and child with TP-1229 and TP-1229-P, respectively.

AEIOUTIPS is a mnemonic tool that can be used to review potential causes of ALOC.
A – Alcohol, abuse, atypical migraine
E – Epilepsy, electrolytes
I – Insulin (hypoglycemia)
O – Oxygen, overdose
U – Uremia (kidney failure)
T – Trauma, tumor
I – Infection
P – Psych, poisoning
S – Seizure, Subarachnoid hemorrhage, Sepsis, Stroke
A past medical history and physical examination may provide clues to determining a likely underlying cause.

A full assessment is performed on the 2 year old.  His appearance is abnormal as he is difficult to arouse and is not responsive.  His skin appears flushed.  His vital signs are HR 140, BP 94/42, RR 14, O2 saturation 96%.  His blood glucose is 99mg/dL.  IV access is obtained.  Cardiac monitors demonstrate sinus tachycardia.

Paramedics obtain further history about the mother and learn that she is typically healthy with no prior medical or psychiatric history.  She has never used any elicit drugs according to her husband and rarely drinks alcohol.  On physical examination, her skin is flushed and dry.  Pupils are mid-sized and react equally to light.  No evidence of trauma is noted.  On the monitor, the rhythm is sinus tachycardia with no signs of ischemia or infarction.  Blood glucose is 110 mg/dL.  IV access is obtained.

After going through AEIOUTIPS for possible causes for the patients’ symptoms, an astute paramedic considers carbon monoxide poisoning.  It is a cold day and the patients’ home is heated by a natural-gas powered heater.   The paramedic confirms that the heater is turned on.  There is no carbon monoxide detector found in the home.

Carbon monoxide (CO) is a by-product of incomplete combustion of carbon-containing subtances.  It is a colorless, orderless, and tasteless gas.  Exposure is most commonly from automobile exhaust, faulty heaters, or structural fires.  It is estimated that confirmed cases of unintentional, non-fire related CO poisoning results in over 15,000 emergency department visits and nearly 500 deaths per year in the United States1.

CO binds to hemoglobin in red blood cells forming carboxyhemoglobin.  The formation of carboxyhemoglobin prevents oxygen from binding to hemoglobin, leading to hypoxia by disrupting normal oxygen delivery to cells.  CO poisoning can manifest through a broad range of symptoms dependent on the concentration of CO and the duration of exposure.

Although patients are physiologically hypoxic, oxygen saturation by pulse oximetry will typically read as normal because the SpOreading will incorporate both the percentage of hemoglobin that is saturated with oxygen (oxyhemoglobin) as well as carboxyhemoglobin in the reading.

Exposure to high levels of carbon monoxide result in toxic effects.  Early symptoms may be “flu-like” and include headache, dizziness, vomiting, and fatigue.   Severe exposures result in confusion, loss of consciousness, focal neurological deficits, or death.  Flushing of the skin may or may not be present in symptomatic patients and the classically taught “cherry-red” skin finding is seen in only a small percentage of patients.

Case presentation

2NEJM. Carbon Monoxide Poisoning. 2009;360(12): 1217-1225

California law requires CO detectors in residential dwellings3 however, not everyone is compliant.   CO poisonings occur each year, particularly during winter months.

The first step in treating CO poisoning is recognition of the signs and symptoms.  One important clue is when more than one person in a household or location is symptomatic, such as in this case. One may not be able to make a definitive diagnosis at the scene, but if suspected, the patient should be removed from the source of carbon monoxide and carbon monoxide poisoning should be treated with high flow oxygen as per TP 1238 and TP 1238-P.  High flow oxygen will expedite the displacement and elimination of carbon monoxide from hemoglobin.  Paramedics should also assess for ongoing hazards and other potential victims.  If a carbon monoxide detector is available, paramedics should consider obtaining a measured carbon monoxide level and reporting results to the receiving hospital as this information is useful for diagnosis and treatment decisions.  Initiating treatment should be a clinical decision and not rely on measured confirmation of carbon monoxide  exposure or a carboxyhemoglobin level.

Young children may not be able to communicate symptoms of carbon monoxide poisoning.  For this reason, their symptoms may be non-specific and present as ‘fussiness’.  Young children are more at risk to develop severe symptoms from CO exposure due to affinity of CO molecule for fetal hemoglobin and the higher metabolic rate which may result in more rapid poisoning. The management of CO poisoning is the same, regardless of age.

Paramedics administer high-flow oxygen at 15L/min to both patients and immediately remove them from the home.   The potentially faulty heater was turned off and a field CO monitor detected elevated levels of CO within the house.  Neither the first responders nor the patients’ husband/father developed symptoms.  The patients were transported to the nearest hospital (which was also a Pediatric Medical Center given the 2 year-old’s persistent altered mental status) where the detected CO level was communicated to the hospital patient care team.  By the time of arrival, the mother was significantly improved.  The child was responsive but still altered requiring inpatient management.  The mother was discharged from the emergency department after treatment and the child was admitted for further management.  Both patients made a full recovery.


  1. Centers for Disease Control and Prevention (CDC) Carbon monoxide exposures – United States, 2000–2009. MMWR. 2011;60:1014–1017.
  2. NEJM. Carbon Monoxide Poisoning. 2009;360(12): 1217-1225
  3. http://www.leginfo.ca.gov/pub/09-10/bill/sen/sb_0151-0200/sb_183_bill_20100507_chaptered.pdf  Accessed November 7, 2018