Studies Evaluating Pulse Oximetry in Stroke Patients

Author/Year/

Country/Study Design/ N

Methods

Outcome

Ramsey et al. (2006)
UK
N=189

 

Population: Stroke.
Protocol: Patients received a bedside swallowing assessment (BSA), pulse oximetry and VMBS (n=54) studies. Two cut-points were selected to determine the presence/absence of oxygen desaturation (>2% and >5%).

 

  1. 15 (28%) demonstrated aspiration on VMBS. Of these, 2% desaturation was seen in 5 (33.3%) of these patients and in 2 (13.3%) when >5% threshold was used.
  2. 7/15 patients (47%) with demonstrated aspiration, failed the BSA.
  3. The sensitivity and specificity associated with >2% destauration were 33% and 62% and were 13% and 95% for an oxygen desaturation threshold of >5%.

Wang et al.
(2005)
Taiwan
Observational
N=60

 

Population: Stroke (45%).
Protocol: Patients received both oxygen saturation and VMBS evaluation. Oxygen saturation was monitored for 5 minutes before and for 5 minutes after the VMBS evaluation.

 

  1. 23/60 patients enrolled in the study, demonstrated aspiration on VMBS study. Of these patients 9 displayed significant oxygen desaturation (a drop of > 3% was considered significant).
  2. Of the 37 patients who did not demonstrate aspiration on VMBS, 15 had an episode of oxygen desaturation.
  3. The sensitivity and specificity were 39.1% and 59.4%, respectively.
  4. The positive and negative predictive values were 37.5% and 61.1%, respectively. The positive likelihood ratio was 0.96.

Smith et al.
(2000)
UK
Observational
N=53

 

Population: Stroke.
Protocol: Patients received a bedside evaluation, pulse oximetry and a VMBS evaluation of swallowing. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated for both the bedside evaluation and pulse oximetry.

  1. 15 of 53 patients aspirated on VMBS examination.
  2. The Sensitivity, Specificity, PPV (Positive Predictive Value) and NPV (Negative Predictive Value) for pulse oximetry to identify aspiration were 87%, 39%, 36% and 88%, respectively.

Sherman et al. (1999)
USA
Observational
N=46

Population: Stroke (34.8%).
Protocol: Patients with swallowing difficulties underwent VMBS evaluation with simultaneous oxygen saturation monitoring (with a 5-6 second sampling interval).

  1. 12/46 patients (six with stroke) aspirated on VMBS.
  2. Patients who aspirated had a significantly greater decline in oxygen saturation compared to those who did not aspirate.
  3. The lowest O2 saturation value among patients who aspirated was 81% compared with 92% among patients who did not aspirate/penetrate.

Sellars et al.
(1998)
UK
Observational
N=6

 

Population: Stroke (66.7%).
Protocol: Patients with established dysphagia underwent both VMBS evaluation with simultaneous oxygen saturation monitoring. A decline in 02 saturation of 4% from baseline was considered clinically significant.

  1. 4 patients demonstrated aspiration of VMBS. Of these, two exhibited significant O2 desaturation.

Collins & Bakhei (1997)
UK
Observational
N=54

Population: Stroke.
Protocol: Patients with swallowing difficulties received a VMBS study and simultaneously had their arterial oxygen saturation measured. The barium meal consisted of 150 mL liquid, 3 oz. mousse and biscuit. A drop of 2% in the arterial oxygen saturation was considered clinically significant. Oxygen saturation was measured during swallowing, 2 minutes after the test meal and 10 minutes after the VMBS study was completed.

  1. 22 patients demonstrated aspiration on VMBS evaluation.
  2. Correlation of the pulse oximetry results with VMBS findings showed that 12 (55%) of the patients who aspirated had a significant degree of oxygen desaturation at the point of swallow/aspiration, but none of the nonaspirators desaturated by ≥ 2%.
  3. When the results of oximetry at swallow/aspiration and at 2 minutes after swallowing were combined, 16 (73%) of the aspirators could be identified by this method, and 4 (13%) of the nonaspirators also had a significant oxygen desaturation.
  4. 44 patients (81.5%) were accurately predicted as aspirators or nonaspirators ( = 0.61, P<.001). Prediction was better for males compared to females.
  5. The sensitivity and specificity of pulse oximetry were 73% and 87%, respectively.

Note: VMBS=Videofluoroscopic Modified Barium Swallow