Pulse Oximetry as a Fifth Vital Sign in Emergency Geriatric Assessment

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PULSE OXIMETRY

Mower et al.

PULSE OXMETRY AS GERIATRIC VITAL SIGN

Pulse Oximetry as a Fifth Vital Sign in Emergency Geriatric Assessment WILLIAMR. MOWER, MD, PHD, GORDON MYERS, MD, EMILYL. NICKLIN, BS, KATHLEEN T. KEARIN, BS, RN, LARRY J. BWF, MD, CAROLYNSACHS, MD Abstract. Objective: 'Ib determine the utility of pulse oximetry as a routine fifth vital sign in emergency geriatric assessment. Methode: Prospective study using pulse oximetry to measure 0, saturation in geriatric patients presenting to ED triage. Saturation values were disclosed to clinicians only after they had completed medical evaluations and were ready to release or admit each patient. The authors measured changes in medical management and diagnoses initiated after the disclosure of pulse oximetry values. The study included 1,963consecutive adults aged 265 years presenting to triage at a university ED. Measurements included changes in select diagnostic tests: chest radiography, complete blood count (CBC), spirometry, arterial blood gases (ABGs), pulse oximetry, and ventilation- perfusion scans; treatments: antibiotics, p-agonists, and supplemental 0,; and hospital admission and final diagnoses that occurred after complete ED evaluation when physi-

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ESPITE the fact that emergency physicians are frequently required to evaluate respiratory status of older individuals, there exists a paucity of modern data describing geriatric respiratory assessment.' Simple clinical signs, including respiratory rate, presence of retractions, cyanosis, pallor, and general appearance, are used to assess cardiorespiratory status in children. Previous investigators have found that while these clinical signs are frequently present, their absence does not reliably exclude the possibility of serious cardiopulmonary disease or lower respiratory tract infections.,-7 Pulse oximetry has been advocated as an accurate, simple, and noninvasive method of measuring arterial 0, saturation.8 Pulse oximetry can accurately measure normal saturations (SaO,) and

cians were informed of triage pulse oximetry values. Results: 397 (20.2%) geriatric patients had triage pulse oximetry values 64 years of age repeated and the results were made available to presenting to emergency triage were enrolled. Pa- the requesting physician. Physicians were asked to complete a brief questients were excluded from the study if they bypassed triage and were judged by the triage nurse tionnaire when they were ready to release or admit or out-of-hospital care personnel to be in need of each patient. Physicians were asked to specify immediate resuscitation or medical intervention. whether chest radiography, complete blood count Patients were also excluded if the triage nurse was (CBC), spirometry, arterial blood gases (ABGs), unable to measure respiratory rate and pulse ox- pulse oximetry, or ventilation-perfusion scanning imetry according to study protocols. The study was had been used in evaluating each patient, and approved and waiver of informed consent was whether antibiotics, P-agonists, supplemental 02, granted by the human subject review board at our or hospital admission had been necessary. Physicians were also asked to supply their release diinstitution. agnosis for each patient. Physicians could not reStudu Protocol and Measurements. Triage ceive the forms needed to release, admit, or nurses assessed each patient and measured tem- transfer patients until they had submitted a comperature, pulse, and blood pressure (BPI using pleted questionnaire. This approach ensured that prestudy triage techniques. Respiratory rates were the physicians would complete the questionnaires measured by placing a stethoscope on the patient’s for all patients. Physicians were given the rechest wall and counting auscultated breath sounds quested disposition forms along with the correfor 1 minute. The nurses then assigned triage pri- sponding triage pulse oximetry value when the orities based on the patient’s complaint and mea- data questionnaire was complete. After receiving the triage pulse oximetry measurements, physisurement of the 4 standard vital signs. After the triage priority was determined, the cians were free to order any additional tests or nurses measured each patient’s 0, saturation us- therapies they thought indicated and were allowed ing a pulse oximeter (Nellcor N-20, Hayward, CA). to alter their dispositions and diagnoses. To determine whether management was altered This portable oximeter measures the absorption of red and infrared light signals until 5 valid pulses by the oximetry results, all diagnostic tests and are detected and then reports a single SaO, therapies were abstracted from the ED medical value.I4 Triage oximetry values represent spot record by a n investigator blinded to the pulse oxmeasurements; the device was not used as a con- imetry measurements. Tests and therapies were tinuous pulse oximeter. We designated fingers to considered to have been ordered prior to oximetry be the preferred site for pulse oximetry measure- disclosure if they were listed on the questionnaire. Diagnostic tests and therapeutic interventions imments. Each patient was assigned a unique identifying plemented after the disclosure of the oximetry

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PULSE OXIMETRY

Mower et al.

TABLE 1. Number (Percentage) of Patients for Whom Additional Diagnostic Tests or Therapies Were Ordered or Changes Were Made in Diagnosis or Disposition after Disclosure of Triage Pulse Oximetry Results in 397 Geriatric Patients with 0, Saturation Less Than 95% ~

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Diagnostic tests Repeat pulse oximetry Chest radiography Complete blood count Arterial blood gas analysis Spirometry Ventilation- perfusion scan

51 (12.8%) 23 (5.8%) 16 (4.0%) 15 (3.8%) 5 (1.3%) 0 (0.0%)

Treatments Antibiotics Supplemental 0, P-agonists

14 29 6

(3.5%) (7.3%) (1.5%)

Hospital admission

9

(2.3%)

Diagnostic changes

27

(6.8%)

measurements (if any) were recorded for each patient, as were the physician's final diagnoses. Data collection was limited to events occurring in the ED and did not extend to events occurring after the patient's disposition.

Data Analusis. To determine whether pulse oximetry measurements altered patient care, changes made in treating geriatric patients with SaO, values