Pulse oximetry in general practice

Pulse oximetry is inexpensive, reliable and acceptable in the context of several areas of care, particularly community acquired pneumonia, evaluation of asthmatic episodes and the management of the febrile child.¹ Despite becoming readily available and affordable, its use in general practice has not yet become standard, with research in 2008 showing only 20% of GPs use a pulse oximeter to assess respiratory status.²

Guidelines highlight common clinical scenarios where pulse oximetry is of clinical importance to GPs.^3-5 These include chronic obstructive pulmonary disease (COPD),³ acute asthma attack⁴ and community acquired pneumonia (CAP).⁵ Given the reduced cost, ease of use, and reliability of pulse oximetry, the aim of this study is to determine if pulse oximetry can be systematically introduced into a general practice setting. 

Method

Between September and December of 2011, finger tip pulse oximeters (figure 1 – picture) were given to 12 GPs (six trainers and six registrars) chosen randomly from the TCD HSE GP Training Scheme. The pulse oximeters were distributed with an information pack, detailing clear indications for use of pulse oximetry in routine case handling.

The study ran for 12 weeks. At weeks one, six and 12, participating GPs completed a feedback form for each patient seen. The questions on the response forms were chosen to provide clear information on clinical findings and the user-perceived usefulness. Questions were based on a previous study.⁶

Results

During the study, 697 consultations were recorded (370 by trainers; 327 by registrars) and the pulse oximeter was used 8% of the time. Use of the device decreased after the initial introductory week (week 1: 11%; week six: 6%; week 12: 7%). At all stages, trainees had a higher usage rate than trainers. 

GPs were asked if knowing oxygen saturation (SpO2) changed the management of the patient. In 26% of cases this knowledge was felt to have altered management. Responses also indicated both patients and doctors found knowing the SpO2 reassuring (75% and 89% respectively).

The most commonly chosen clinical indications were ‘asthma’ and ‘dyspnoea non-specific’ (29% each). Most SpO2 readings were normal with a median SpO2 of 97%. In successive rounds the mean SpO2 was progressively lower (97.2% vs. 96.8% vs. 95.4%).

Discussion

The study demonstrated a successful introduction of pulse oximetry into the general practice setting. Results indicated a trend in use of the oximeter, with doctors using the device more selectively in weeks six and 12, but with the average oxygen saturation readings subsequently decreasing (97.2% vs. 96.8% vs. 95.4%). Meanwhile, GPs reported that the device altered their management more frequently when used, through fast, objective measurement of these lower levels of oxygen saturation.

A 2003 study looked at pulse oximetry use for the management of COPD in primary care centres in England. The device used in the 2003 study cost around E590, while the personal devices in this study cost only E30. The key findings of the 2003 study supported the findings of our study, with the 2003 study showing SpO2 changed management in 19% of cases and reassured the clinician in 67% and the patient in 61% of cases. 

Pulse oximeters should be a standard diagnostic device available to all GPs along with stethoscope, sphygmomanometer and thermometer. This study effectively demonstrates that having a personal pulse oximeter available will alter a GP’s management for one in every 50 consultations. The study supports the designation of SpO2 as ‘the fifth vital sign’.⁷

Finger on the pulse 

This study set out to introduce pulse oximetry systematically in a sample of training practices. By showing the device was used in 8% of consultations, provided reliable readings in 94% of cases, and changed the GP’s management in 26% of these, the study demonstrated an easy and successful introduction of pulse oximetry, particularly as a rapid, non-invasive, inexpensive method of adding certainty in determining the presence of significant levels of hypoxia in the community setting. 

Given the reduced cost, ease and speed of use, reliability and acceptability to GPs and patients, it is recommended that all GPs evaluating acute presentations should closely consider the pulse oximeter as a standard piece of equipment. 

References

1. Pluddermann A, Thompson M, Henghan C, Price C. Pulse oximetry in primary care: primary care diagnostic technology update. Br J Gen Pract 2011; 31: 358-359
2. Thompson M, Mayon-White R, Harnden A, et al. Using vital signs to assess children with acute infections: a survey of current practice. Br J Gen Pract 2008: 58(549): 236-241
3. CG 101: Chronic obstructive pulmonary disease (update). National Institute for Health and Clinical Excellence [NICE] 2010
4. British guideline on the management of asthma. British Thoracic Society [BTS], Scottish Intercollegiate Network [SIGN] 2008
5. Guidelines for the management of community acquired pneumonia in adults. BTS 2009 (update)
6. Jones K, Cassidy, P, Killen J, Ellis H. The feasibility and usefulness of oximetry measurements in primary care. Prim Care Resp Journal 2003; 12(1): 4-6
7. Neff T. Routine oximetry. A fifth vital sign? Chest1988; 94(2): 227