The Vital Signs, Part 3: Respiratory Rate, Temperature and Beyond

     Vital signs give EMS providers insight to what's going on inside our patients and let us evaluate their responses to our interventions. This multipart series takes a fresh look at these vital signs and what they actually tell us in terms of changing our prehospital treatment, predicting the severity of presenting problems and even predicting survival.

RESPIRATION (RATE AND DEPTH)

     In one way, respiratory rate is similar to pulse: It's measured by simply counting, yet studies indicate that even professionals often measure it wrong. A study comparing the counting of respirations by ED triage nurses and electronic devices at a teaching hospital in New York City concluded that neither were accurate for detecting abnormal respiratory rates of less than 12 breaths per minute (bradypnea) or greater than 20 breaths per minute (tachypnea).¹ The importance of respiratory rates was brought into question by a study finding that respiratory rate measurements correlated poorly with oxygen saturation measurements and did not screen reliably for desaturation. Patients with low SaO₂ did not usually exhibit increased respiratory rates. Similarly, increased respiratory rates were unlikely to reflect desaturation. Overall, only 33% of subjects with oxygen saturations below 90% exhibited increased respiratory rates.² With regard to pediatric patients, a study found that in babies under six months old, respiratory rates counted using a stethoscope were 20%–50% higher than those counted from the patient's bedside by observation only. The authors theorized that bedside observers were counting only respirations that moved large amounts of air.³ The review also called into question the value of the respiratory rate as a vital sign.

     There are a few notable respiratory patterns that providers may have heard of. Most are associated with specific disorders or syndromes, and they can be useful in determining extent of injury in coma patients. They include Kussmaul's, Cheyne-Stokes, central neurogenic hyperventilation, Biot's (ataxic) and apneustic breathing patterns.

TEMPERATURE

     While temperature is commonly referred to as the fourth vital sign and recorded on call sheets, there is little research to support its importance to EMS personnel or the need for expensive temperature-recording equipment. One study conducted in a Zambian hospital evaluated the ability of mothers and medical students to detect fever in children using only touch. Both groups were highly accurate, comparable to a mercury thermometer.⁴ Skin temperature is documented as cool, normal or warm, and on some forms cold and hot.

PAIN

     Pain as the "fifth vital sign" was an idea introduced in 1995 by the American Pain Society. American hospitals are now obligated to assess pain in their patients. EMS has started to address this symptom with prehospital pain management research and protocols, especially for burns and extremity fractures.

     As with the previous vital signs, there are problems with identifying and treating this fifth one. Significant disparity exists between paramedics' perceptions of acute pain assessment and frequency of providing analgesia and their actual practice. Children and adolescents have less documentation of pain assessment and receive fewer analgesic interventions compared with adults. Inability to assess pain may be an important barrier to providing analgesia.⁵ Few pediatric patients receive prehospital analgesia, although most ultimately get it in EDs.⁶ Research and education must be done to allay fears about side effects. Prehospital pain management is an important QA/QI/call review topic for agencies.

APGAR

     Virginia Apgar, a physician and anesthesiologist, developed the Apgar scoring system in 1952 to evaluate a newborn's condition at birth. The Apgar score is performed at one and five minutes of life. Newborn infants are evaluated based on five variables: appearance (color), pulse (heart rate), grimace (reflex irritability), activity (muscle tone) and respiratory effort. A numerical score of 0–2 is assigned in each category. The maximum score is therefore 10, with higher numbers being better. Authors have noted that great variability exists in how individual healthcare providers score the assessment.