Rapid response systems (RRSs) have matured dramatically in the last decade and a half, during which time critical care providers decided to carry their expertise beyond the walls of the intensive care unit (ICU) to respond to deteriorating patients on general hospital wards. The foundation for this decision was the understanding that general hospital ward patients exhibit clear signs of physiological abnormalities well before their arrests.1-11

Many retrospective studies have shown that arrests are usually heralded by long periods of hemodynamic and respiratory instability. ICU practitioners have always been aware that patients being admitted to the ICU from the general ward did not suddenly become critically ill; it was only that their illness was suddenly recognized. These practitioners include the doctors, nurses, and, especially, respiratory therapists, who are often involved in care both in the ICU and on the general wards.

The medical community has made a major shift over the last 15 years from simply responding to arrests to actively seeking ways to prevent them from occurring in the first place. The RRS concept has recently been embraced by The Joint Commission as a mandate for American hospitals in the form of National Patient Safety Goal 16 and 16A.12 While this goal does not specifically ask hospitals to create response teams or dictate activation criteria, it requires hospitals to develop systems that “improve recognition and response to changes in a patient’s condition with the organization selecting suitable methods that enable health care staff members to directly request additional assistance from a specially trained individual or individuals when a patient’s condition appears to be deteriorating.” While The Joint Commission does not demand RRSs by name, they are the logical solution for meeting this requirement and have the most support in their favor.

What’s in a Name?

The early RRSs were commonly called medical emergency teams or METs, although other terms were and have been used, including medical emergency response teams (MERTs), patient-at-risk teams (PARTs), critical care outreach teams (CCOTs), and rapid response teams (RRTs). Many use these terms interchangeably, but consensus terminology exists that should be used when reporting and sharing information and data.13,14

This consensus suggests that the term rapid response system should be used to refer to the entire system for responding to all patients with a critical medical problem. In the broadest sense, this can include the team that responds to codes and the team that responds to deteriorating patents prior to an arrest (sometimes they are one and the same) as well as other specialized teams that may exist within the hospital, such as a difficult airway response team or massive transfusion team; however, the term RRS is preferably used to refer to systems that seek to prevent deterioration and arrests rather than respond to arrests.

Rapid response systems take many forms; there is no one preferred model, since direct head-to-head comparisons between models have not been performed. Terminology, however, is based on the team structure and functionality.13 Teams that include physicians, but may also include RTs and others, are called medical emergency teams, while teams that do not include physicians as responders are properly called RRTs. Teams that provide follow-up service on patients previously discharged from the ICU, as well as responding to any deteriorating general ward patient, are described as CCOTs. Despite these definitions, what becomes clear, both in the literature and by experience, is that RTs can be and should be a primary component of the responding team (the “efferent” limb). The reason lies in the fact that the majority of problems that develop into critical illness on the general wards and are at risk of deteriorating to arrest either are respiratory in nature or have a respiratory component as a major part of the pathology.

The Roots Are Respiratory

On general hospital wards, patients usually do not suddenly develop arrhythmias such as ventricular tachycardia and ventricular fibrillation and arrest. This is especially true in children who have a high rate of respiratory problems as the cause of their arrests. More often, ward patients develop or are found in pulseless electrical activity (PEA), asystole, or an agonal rhythm. While the reasons for these arrhythmias are many, a substantial number include respiratory problems as their inciting cause. For example, the classic causes of PEA include pulmonary embolus, acidosis (respiratory from hypoventilation or metabolic), tension pneumothorax, hypoxia, hypovolemia, and cardiac tamponade. The first four all are primary respiratory problems or have clear respiratory symptoms. Additionally, the physiological criteria commonly used for activating RRSs (the “afferent” limb) are heavily based on respiratory elements. These activation criteria typically include hypoxia, respiratory distress, shortness of breath (SOB), tachypnea, hypopnea/hypoventilation, tachycardia, bradycardia, hypotension, severe hypertension, mental status change, new onset seizure, chest pain, and general worry or concern on the part of the ward staff.8-11

The first five of these criteria are obviously respiratory, but the others are tightly linked to respiratory problems as well. The first and most life-threatening cause of tachycardia is hypoxia. For severe hypertension, hypoxia also needs to be first on the list of possible causes but so does hypopnea/hypoventilation (leading to hypercapnia). Mental status change may have many causes, but hypoxia and hypoventilation are the most immediately life-threatening, and mental status change from other causes may result in failure to effectively protect the airway, requiring respiratory therapy interventions (artificial airways, etc). Bradycardia is often the result of severe and prolonged hypoxia. Given what we know about the nature of these early signs of deterioration and impending arrest, early recognition and intervention by RTs, along with physicians and nurses, should have a tremendous impact on the prevention and/or management of many of these problems and the reduction of the incidence of arrest and mortality.

This becomes apparent as we look at the results of having an RRS in place. In studies that list the “reasons for activation” for their teams, respiratory reasons (hypoxia, SOB, respiratory distress, etc) are at the top of the list. Our experience at the Johns Hopkins Hospital echoes this. For our adult RRS program, almost 70% of the activations are for respiratory problems—and the rate is higher for pediatrics. Additionally, many of the activations based on other criteria result in the responding team finding that the patient is also having respiratory problems (often hypoxia from sepsis-induced shunting). While the specific percentages vary from institution to institution, this is a common experience.

Workload Imbalance = Unmet Needs

Why the high rate of already-existing respiratory problems? Some of it has to do with the patient’s disease processes (such as new-onset infection/sepsis), but much has to do with unmet patient needs. The nurse-to-patient ratio drops dramatically when patients leave the ICU. Ratios range from 1:6 to as high as 1:10 depending on the ward and the time of day. Nurses often cite imbalances between patient acuity and need, with staffing levels as a major problem and a common reason for admission or readmission to a higher level care setting, such as the ICU or intermediate care unit (IMC). It is even more severe for RTs who may cover one or more wards—including an ICU—at the same time. This workload imbalance may impact their ability to effectively manage their patients. We do know that during code situations, patients other than the patient experiencing the event often experience medication errors, and that these errors are usually (90%) respiratory therapy treatments. This clearly points to the stresses that occur when acuity is high.15 This gets to the core of why there are RRSs to address the mismatch between the patient’s emergent unmet needs and the available resources on the general wards.13

Even though respiratory problems are common as a central contributor to or sign of impending deterioration, determining who is developing these unmet needs remains difficult. Using physiological limits and “worry or concern” as activation criteria has been validated as effective,16 but the sensitivity and specificity of physiological limits for preventing arrest is unclear. Attempts to use scoring systems, such as scaled composite scores of various types, have not necessarily improved the situation. Many have reported successful results,8,9,17-24 but others have poor inter-rater reliability in assigning and calculating these scores.25 Detection of real abnormalities does not improve by creating more complex vital sign scoring systems, nor does it improve by simplifying the scoring systems. Likewise, modifying the cut-offs on existing vital sign scoring systems (ie, heart rate cut-off of 140 versus 130) does not seem to make much of a difference either.25-29

More than Technology Is Needed

One possible explanation for these conflicting results is the frequency with which patients are monitored on general wards, which is rarely more frequent than every 4 hours and usually every 8 hours. Vital sign changes in general ward patients exist for a median of 6 to 7 hours prior to their arrest.3 If vital signs are taken only every 8 hours, there are significant opportunities to miss a serious problem. This is made worse by the knowledge that these abnormalities are often not viewed as serious. Wireless mobile continuous electronic monitoring systems may help to solve these problems, but acceptable signal-to-noise ratios (especially for respiratory-related parameters) are necessary to prevent missed opportunities to rescue without overloading the response system with false alarms. Technologies are developing to better address these issues,30,31 but we should leverage the contribution other providers, such as RTs, have to offer in identifying patients experiencing difficulties now. Respiratory therapists are educated to recognize the problems that seem to be central to so many of these events. While this respiratory therapist resource is also spread thinly, RTs should view themselves as watchdogs who can support the afferent limb of RRSs through early recognition of respiratory signs and symptoms. Activating METs or RRTs is not simply the responsibility of nurses and house staff. While this has not been directly studied, such contributions would seem likely to enhance RRSs.

Respiratory therapists also clearly have a central role to play in the efferent limb. The efferent limb may be staffed many different ways depending on the human resources available (ICU physicians, hospitalists, nurse practitioners, physician assistants, fellows, etc), and there is no data to support one staffing model over another. Thus, staffing often ends up depending on local resources and culture. Since we know respiratory problems exist in so many activations, it is logical to include RTs on the responding team. Having to subsequently call an RT after the team has arrived likely wastes time in delivering appropriate therapy during these common situations. Also, since RTs are involved in managing airways at many hospitals when no anesthesiologist or CRNA is available, they have additional essential skills to bring to bear when the airway is at risk.

Practice Makes Perfect

Team training is essential to good team function, and this training should include all members of the responding team including RTs. One of the best ways to achieve good team function is through simulation. Simulation is a powerful tool for understanding how teams function, identifying opportunities for improvement, and developing and testing protocols for care in urgent/emergent situations such as those frequently encountered by RRS teams,32 and does not require an expensive simulation laboratory. Education has been often cited as being essential to RRS success.33-35 This education works not only at the responding team level but also at the general ward staff level to change the culture of the institution to view arrests as “never should happen” events, attune all providers to be aware of the signs and symptoms of developing critical illness, and empower them to get help when they deem it necessary. Through this, new plans can be developed and communicated and resource/needs imbalances accounted for, resulting in an effective triage and care plan for the patient.


Rapid response systems can result in significant reductions in the incidence of arrest and, in many settings, reduced mortality,36-53 as well as improvement in process-of-care measures such as meeting sepsis management guidelines and appropriate institution of “Not for Resuscitation” status54-56 and patient and nursing satisfaction.57-59 Rapid response systems change culture, and culture is a crucial element of the health systems in which we work. Rapid response systems can be used to inform hospital quality-improvement processes through assessment of arrest and near-arrest events.13,33 The recent addition of MET data fields to the American Heart Association’s National Registration for CPR database60 can help generate the kinds of data necessary to understand what is happening in your hospital so effective strategies can be put into place to improve outcomes for patients developing critical illness, respiratory compromise, and/or hemodynamic instability. Given what we know about these events and the high prevalence of respiratory compromise that occurs as a cause or result of these deteriorations, RTs are clear stakeholders in this process and should be fully involved in the afferent and efferent limbs of RRSs and in the process of quality improvement for general ward patients. They are providers right along with the nurses and doctors and should see this role as central to their practice and their contribution to the institution and patient care.

Bradford D. Winters, MD, PhD, is director of the medical student education program; director, adult rapid response team project; co-chair of the CPR committee; intensivist and assistant professor, Department of Anesthesiology/CCM and Surgery at the Johns Hopkins University School of Medicine and the Johns Hopkins Hospital. For further information, contact [email protected].


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