What a great morning! The Attack One crew came on duty at 0800, and it's warm already. May is a relatively slow month for operations, but great for training. Crews had recently been introduced to some new equipment for evaluation and treatment, including new airway options and some rapid-clotting materials. But when the dispatcher tones out a report of "child ill," the crew is off.
They arrive at a home in a residential area and are met by a concerned set of parents. "We're both sick, but we're more concerned about our middle child," the father says. "She's been sicker than the rest of us. She was up for a couple of hours vomiting, and now we're having a hard time waking her up. We called our pediatrician, and she wants us to have her checked at the hospital for the flu."
The crew heads upstairs to check the little girl. As they get to the top of the steps, a retching boy rushes past and into the bathroom. The crew turns toward the bathroom, but mom stops them. "That's our oldest, but he's not as sick as our daughter," she says. "She's in the last bedroom down the hallway."
"Who all is actually sick here?" the paramedic asks.
"I guess we all are," the father answers. "We all ate the same food at a picnic yesterday, and we all got sick early this morning. We're keeping the kids home from school."
The father leads the crew to the side of a girl of about 8, who is curled up in bed, holding her head. She is easily aroused by the medics, but cries and says her head hurts. She's not warm to the touch, and has a regular pulse that's not tachycardic. Pulse oximetry shows a heart rate of 98 and an oxygen saturation of 99%.
Mom comes in with a report on the boy: He vomited once and went back to bed. Mom says this made her feel ill also, and she vomited as well. Also, the other daughter isn't waking up in her bed.
That child, age 4, is in a room at the opposite end of the hall, and one crew member quickly moves to check on her. Like her sister, she's crying, and as the medic goes to pick her up, she vomits also.
Three ill children, and mom has vomited too. How is dad feeling? "Not good," he tells them. "Dizzy, and a little headache."
By now, the paramedic has an ominous suspicion. "How is this home heated?" she asks.
"Electric, but we haven't had the heater on in weeks because it's been so warm," dad says. "Yesterday we even closed up the house and turned the air conditioning on."
"Any natural gas or propane appliances?" the medic asks.
"Our water heater and oven are gas," the father replies.
The paramedic makes a quick decision: "Let's all go outside," she says, "and we'll complete a check on everyone out there."
The crew leads everyone out front, carrying the children. One of the EMTs recognizes the paramedic's concern and asks if there are carbon monoxide detectors in the house. There are not.
All five family members are checked outside. All have stable vital signs and pulse oximetry readings in the upper 90s. All are ill, with varying degrees of head pain and nausea; all but one has vomited. No one is febrile. None are passing blood when they vomit or have had diarrhea.
A crew member retrieves a new piece of monitoring equipment purchased by the department: a pulse CO-oximeter, used for evaluation of possible carbon monoxide exposure. It measures the percentage of hemoglobin molecules that have attached carbon monoxide, a number that, in non-smokers, should not exceed 5%. But readings are elevated in all five family members: The father has a level of 28%, the mother 23%, and the children around 20%.
The crew attaches all five to high-flow oxygen masks and explains to the patients that they've been exposed to carbon monoxide. They will all need to be treated at a hospital, and may need to receive hyperbaric oxygen (oxygen delivered at higher-than-atmospheric pressure). The family asks to be treated at the same hospital, and a facility with a hyperbaric chamber is contacted. Transport will be accomplished in two ambulances.
A hazmat team arrives to assist and finds high levels of carbon monoxide in the house, with the highest concentrations in the upstairs bedrooms. The source is found to be the water heater: the flue had been occluded by a bird's nest. The water heater is shut off.
Before the family leaves, they are informed of the source of the problem. Fire responders offer to stay on scene to meet a plumbing contractor who's been called, and will ventilate the house to allow occupancy later in the day. There are no pets in the house, and no one else was present in the last 24 hours.
The Attack One crew organizes the transport operation, putting a parent in each ambulance, one traveling with one child, the other with two. All receive high-flow oxygen en route.
Table 1: Organizing Patient Management
Many fire and EMS organizations use triage systems that result in patients being numbered in sequential fashion. This represents the results of that process here. The crew triaged five patients, categorizing them by compromise of the ABCDE body systems.
At the emergency department, venous blood testing confirms the diagnosis of carbon monoxide poisoning. After a meeting of the pediatrician, emergency physician and hyperbaric oxygen physician, the plan is to have each of the children treated with hyperbaric oxygen. This is because all three were ill with headaches and vomiting, and two had periods of altered level of consciousness. The parents are treated with high-flow oxygen.
The Attack One crew arranges a clearance of the house with the fire department after the repairman has cleared the flue and tested the water heater. All five patients are released home later that day.
Multiple victims in one building with similar symptoms alerted the crew to consider poisoning as a source. Multiple-victim incidents are typically caused by trauma, poisoning or infectious diseases. At incidents with more than one patient, crews should consider all three. Infectious diseases, including food poisoning, can cause multiple patients to have similar symptoms with onsets around the same time. Food poisoning in North America typically presents with vomiting and (occasionally bloody) diarrhea. Rare causes may lead to altered LOCs.
Carbon monoxide is a simple and toxic substance. It binds to hemoglobin and to the parts of cells that metabolize oxygen. Hemoglobin that's occupied by carbon monoxide is called carboxyhemoglobin. Ambient air contains a very small percentage of carbon monoxide, and bodily metabolism produces a very small amount. For persons who don't smoke cigarettes, the normal level of carboxyhemoglobin can range up to 5%. Persons who smoke have levels up to 10%. Studies have found that carbon monoxide poisoning may cause early death from cardiovascular causes in those who survive an initial incident.
Carboxyhemoglobin is an unsuspected agent in many patients evaluated in emergency systems, whether in the field or in the emergency department. Standard pulse oximeters have algorithms that analyze the infrared signals from the human body, but exclude carboxyhemoglobin, so pulse oximetry may still show oxyhemoglobin levels near 100% even when a patient is severely poisoned with carbon monoxide.
Testing for carbon monoxide poisoning has traditionally relied on a blood test that measured the percentage of hemoglobin occupied by carbon monoxide instead of oxygen. Another method is breath sampling with an inline detector: The person breathes into a tube, and the exhaled air is analyzed and the partial pressure of carbon monoxide calculated. This correlates with the amount of CO in the alveoli, and then the bloodstream.
We typically consider carbon monoxide as a winter problem. But incidents can occur across all seasons, particularly in buildings that use hydrocarbon fuel sources and are closed up against the weather. Even in new buildings, a malfunctioning appliance or exhaust flue can cause high levels of CO to be released. A now-frequent cause of CO poisoning is the use of gasoline-powered generators when power outages occur.
Customer Service Elements
The first element of good emergency management is recognizing a life-threatening situation and preventing unnecessary harm. In many emergencies, such as poisoning events, it is necessary to look beyond the first patient. Clearly, in carbon monoxide incidents, the first patient may be the "canary in the coal mine," and crews must identify and evacuate others at risk (not forgetting pets), find the source and correct any problem before allowing occupancy.
The Attack One crew had to manage a whole family that was exposed and transport members to the same emergency department. Doing this allows ED staff to treat parents and children together, significantly reducing family stress and allowing immediate information exchange. When an EMS unit removes a whole family, someone has to secure the home, and in this situation the fire department could arrange a safe mitigation of the problem and clear the house before the family's return.
Jim Augustine, MD, FACEP, is the medical director for a number of fire services in the Atlanta area, including Atlanta Fire Rescue. He is a member of EMS Magazine's editorial advisory board. Contact him at email@example.com.
Disclosure: Dr. Augustine serves as a consultant to Masimo Corp., a maker of monitoring technologies that include pulse CO-oximetry, and on the Masimo EMS Clinical Advisory Board.