Colorized transmission electron micrograph of Avian influenza A H5N1 viruses (seen in gold). Image provided by CDC/C. Goldsmith, J. Katz, and S. Zaki.
Patient Triage During Pandemic Influenza
By Grattan Woodson, MD, FACP
One thing that is different about a major pandemic is just how hard it hits patients and how rapidly it kills. Patients affected by the flu can be broadly categorized into 3 prognostic types. In medicine the term prognosis means the likely outcome for the patient with the disease. Patients with a good prognosis are expected to recover, and those with a bad one probably will not. How can I give you a prognosis on a patient I have never seen before? This is a medical skill that comes with experience, evaluating thousands of patients over the course of many years of practice. It comes from understanding the natural history of the common chronic diseases, and how they interact with acute infectious diseases like flu.
Triage is a medical skill that combines an assessment of the prognosis of a patient with knowledge of the medical resources presently available for treatment. The triage process is used to assess all patients presenting with an illness in order to develop a priority list for the rational use of limited resources. It is used routinely in the ER to decide which patient is treated first and who has to wait. It is used in crisis situations where there are mass casualties or many ill people and the available resources are inadequate to provide for everyone. In the triage process, patients are divided into three groups. The available limited resources are concentrated on the middle group that can best use them, with less intense care being given to two other groups. Those receiving less include people so severely ill or injured that the currently available resources are inadequate to help them, and on the other extreme, people who will survive even without receiving the scarce resources that are being allocated. The middle groups are those patients who will probably survive if they are treated, but are likely to die if they are not. The purpose of triage is to concentrate the use of scarce materials or staff on these middle groups.
When practiced with skill and decisiveness, triage results in the best outcome for the most people. It is essential that triage be employed effectively when medical resources are scarce, as they most certainly will be during a severe influenza pandemic. Since many patients with a good prognosis will recover without use of some but not all scarce resources, medical judgment needs to be exercised as to who gets what when. The purpose is to get the most benefit out of the resources available for the most people.
With regard to pandemic bird flu, I have sketched out three broad prognostic categories for you to work with that are designed for care of the ill at home. The first type has a poor prognosis no matter what is done for them. The second might survive if there was full access to medical care and resources like antibiotics and ventilators. The third type is highly likely to recover from the flu as long as they are provided with consistent low-technology supportive measures that can be administered in home settings. Fortunately the overwhelming majority of those who get the flu will be in the last and best prognostic category.
Type 1 patients have the poorest prognosis and almost all will die within 2 or 3 days of the development of their first symptoms. The cause of death in these patients during the 1918 flu was massive respiratory failure from overwhelming entry of inflammatory cells and fluid into the lungs, called cytokine storm. There was no effective treatment for this in 1918, and there is none today despite all the advances in medicine that have occurred over the last 90 years. Signs and symptoms of Type 1 patients include rapid onset of severe shortness of breath, cyanosis (bluish discoloration of the skin of the hands, feet, and around the mouth and spreading centrally), or bleeding from the mouth, gums, throat, lungs, stomach, rectum and under the skin. Here is an excerpt from a letter written by a young US Army doctor assigned to the care of a large number of WWI recruits that developed influenza at Camp Devens, MA in 1918. In his letter to a colleague, the doctor describes the presentation of what we now call cytokine storm in these young healthy men.¹
“These men start with what appears to be an ordinary attack of La Grippe or Influenza, and when brought to the hospital they very rapidly develop the most vicious type of Pneumonia that has ever been seen. Two hours after admission they have the Mahogany spots over the cheek bones, and a few hours later you can begin to see the Cyanosis (a bluish discoloration) extending from their ears and spreading all over the face, until it is hard to distinguish the colored men from the white. It is only a matter of a few hours then until death comes, and it is simply a struggle for air until they suffocate. It is horrible. One can stand it to see one, two or twenty men die, but to see these poor devils dropping like flies sort of gets on your nerves. We have been averaging about 100 deaths per day, and still keeping it up.”
We understand today that cytokine storm is not pneumonia, but instead is a massive immune reaction to the influenza virus.² In many respects it can be seen as an immune over-reaction that leads to severe organ damage. The damaged lung tissue fills with fluid and becomes unable to pass oxygen into the blood. This results in a progressively lower blood and tissue oxygen level and is responsible for the bluish discoloration of the skin we call cyanosis. The mahogany spots developing under the skin described in the doctor’s letter are due to spontaneous bleeding under the skin. Coughing up blood, vomiting blood, passing blood from the rectum and bleeding under the skin are signs of an uncontrolled bleeding condition called consumptive coagulopathy. This syndrome happens when almost all the body’s platelets (clot forming blood cells) and clotting factors (blood proteins that form clots) are consumed in the cytokine storm occurring in the lung and other organs like the liver. Uncontrolled and widespread bleeding is the result. This is a fatal condition for virtually 100% of the people treated at home and many treated in the hospital.
To be perfectly honest, we don’t know nearly enough about cytokine storm the adult respiratory distress syndrome (ARDS) it causes. ADRS has many causes other than influenza. The experience treating ARDS without consumptive coagulopathy in a well equipped and staffed US ICU results in survival of about half the patients. This will be a uniformly fatal complication of bird flu when it develops in a patent without access to these hospital resources. There is no way to predict who may or may not develop cytokine storm ahead of time, except that it is much more common in young healthy adults between age 15 and 40 than anyone else. Based on the experience of similarly ill patients with H5N1 treated in fully equipped and staffed high-tech intensive care units (ICUs) in Southeast Asia during the ante-pandemic phase, my guess is that 50% will survive this complication if they have access to a staffed ICU bed and respiratory ventilator in a functional hospital.³
Pneumonia due to a bacterial infection attacking the lung damaged by flu is the most likely pulmonary complication of flu, with stroke and heart attack heading the list of expected cardiovascular complications. When these complicate pandemic influenza, a 50% survival rate is a reasonable expectation for patients having access to a staffed hospital bed. I have used this same value for pandemic conditions considering that as H5N1 adapts to humans, its lethality will probably fall, as will the functional efficiency of the ICU setting. My assumption is that these two factors will offset each other to a large degree. If ICU hospital care is not available then even under good home care conditions, almost all of these patients will die. I have assigned a 5% survival rate under home conditions for these gravely ill Type 1 patients.
Type 2 patients are very ill with the flu and have significant pulmonary or cardiovascular complications, but they do not die after 3 days like Type 1 patients with cytokine storm. Patients in this prognostic type include all elderly, very young children, or adults with chronic medical disorders by definition. Patients with emphysema or chronic bronchitis from tobacco use and children with asthma are at very high risk of suffering a pulmonary complication during influenza. These include pneumonia, anoxia (low blood oxygen), cyanosis, and severe bronchospasm (shortness of breath from tight breathing tubes) in the case of the patient with asthma. Patients with diabetes are at high risk for a number of varied and severe complications during influenza. Patients with coronary heart disease and high blood pressure are at risk for a heart attack or stroke.
The very young and old are just much more easily overwhelmed by the power of flu and are particularly vulnerable to dehydration. There is nothing wrong with them; it is just that their physical resources are not able to hold up under the strain and they become more easily dehydrated. Patients with chronic medical disorders may already be weakened by their underlying illness, and this causes them to be much more vulnerable to the ravages of influenza.
Pregnant women are a special high-risk group. During the 1918 pandemic, they had some of the highest mortality rates recorded. If at all possible, it would be wise to avoid becoming pregnant any time during an influenza pandemic.
It is likely that 85% of these patients would survive if they had access to a modern Medical Center that could provide IV antibiotic therapy, diagnostic testing, ICU therapy and ventilators when needed, and expert medical care. These resources may not be available during a major pandemic. Under the best of circumstances, patients this sick will have only a 50/50 chance of surviving in the good home care setting. When the outcome is death, it may take several weeks or longer after the patient becomes ill. Many of these deaths are due to secondary complications of influenza rather than to the virus itself. It is common for the patient with a secondary infection to show initial improvement from their flu symptoms, but then become ill again. Often, they present with a return of malaise, aches and pains and then fever. These need to be aggressively managed if they occur. Most commonly secondary infections occur in the lungs, bronchial tree (bronchitis), sinuses, or ears. Virtually all these secondary infections respond to the antibiotic azithromycin, which is indicated for community acquired pneumonia.
Type 3 patients make up the majority of those that become ill with influenza. They have the best chances of making a complete recovery. If they deteriorated at home and were admitted to a functioning hospital, a 99% survival rate would be expected for this prognostic type. On the other hand, if the same patient remained in the home treatment setting, a 95% survival rate is what I project. A lot of people with pandemic bird flu will be severely ill and so weakened by the infection that they will be unable to get out of bed. Many people will be sicker than they have ever been before. This will cause them to think they are dying even when they are far from it. Many Type 3 patients will be completely dependent on others for care. Death in this group is most likely due to dehydration and is therefore completely preventable with good home care. Without simple care, some of these patients will die from preventable causes; but with simple care, almost all of them will recover.
No matter how good the care provided, whether it be in the home or the hospital, some patients will die unexpectedly. This is not your fault. This happens usually because they develop a serious secondary condition that actually becomes the cause of death. Examples of these secondary conditions include bacterial pneumonia, stroke, and heart attack. There is nothing you can do but keep doing the best you can and keep the patient as comfortable as you can.
Patients in extremis, which means they are near death at the time you first encounter them, should not be disturbed unless there is something that you can do to make them more comfortable. Fortunately, patients in extremis are usually already unconscious and beyond suffering.
In my opinion, as a general rule, provide everyone irrespective of prognostic type with the same level of supportive care. This means keep them well-hydrated, clean, warm, and comforted as well as you can. This is a rational course because it is not always possible to predict who will survive and who will not, especially early in the course of the flu, and with kids who can really surprise you. If the hospital is open and you have a Type 1 or a Type 2 patient on your hands, take them to the hospital as soon as possible. If critical medical supplies are in short supply, especially the antiviral drug Tamiflu or other antibiotics, the decision on how to ration these resources is best made by health professionals if they are available. If not, then you will need to use your best judgment.
When it comes to using the scarce medical resources you have available when the hospitals are not open and there is no healthcare professional to take on this burden, you will be required to make these decisions on your own. This is going to be very tough. Keep in mind that the reason it is necessary to make these difficult discriminations and choices during triage is that when done properly, more people benefit than would otherwise be the case.
If you do not have a health professional available to advise you, my suggestion is to concentrate your efforts and precious supplies on those with the best chance of survival, i.e., Type 3 patients. An exception to that rule is healthy children categorized in Type 2 based solely on their age. In my opinion, they deserve full access to scarce resources. In a major pandemic it is unwise to use limited medical resources on critically ill Type 1 or 2 patients, as they are unlikely to survive in the home treatment setting. The hospital is a different situation, and their use or withholding of care is dependent upon a whole different set of circumstances.
Patients classified as Type 2 because of an underlying chronic medical disorder should be considered for access to scarce resources if they are in pretty good health despite the condition. On the other hand, patients who are chronically ill due to their secondary condition are very likely to deteriorate quickly during pandemic flu, and would not be good candidates for recovery even if precious resources were administered to them. So my advice is to focus your greatest efforts on Type 3 patients and select Type 2 patients where the prognosis is best for a complete recovery.
In summary, my advice is to provide basic supportive care to every patient. Consider withholding scarce resources from all Type 1 patients and select Type 2 patients with severe complex underlying chronic illnesses. Specifically, I would consider withholding care treatment from Type 2 adults with advanced chronic disease with poor prognosis due to their underlying condition. I would do everything possible for the well children in Type 2, since they will often make a full recovery given the opportunity, unless they were already severely ill with some other chronic disease. Type 2 adults with well-controlled underlying chronic health problems may be good candidates for use of scarce resources.
These are the most difficult decisions nurses and physicians have to make under emergency conditions, even when they have the advantage of training, objectivity, and experience. I simply cannot fathom how hard it will be for you to have to make them for those you know and love. At a time like this, I have found praying for guidance to be very useful.
¹ First Published in the British Medical Journal, December 22, 1979
² Osterholm M, Preparing for the next pandemic., N Engl J Med 2005;352:1839-1842
³ The Writing Committee of the WHO Consultation of Human Influenza A/H5., Avian Influenza A (H5N1) Infection in Humans. N Engl J Med 2005;353:1374-85.