Cervical Auscultation and pulse oximetry

Cervical Auscultation

Borr et al 2007: Reliability and validity of cervical auscultation

Conclusion

Cervical auscultation = an early warning system for identifying patients at risk of aspiration/penetration but is not a stand alone tool.

Study 1: CA parameters 2 parameters separated older adults from dysphagic adults on the study: The duration of the first swallow burst was shorter in dysphagic adults and dysphagic patients needed more than one gulp to swallow a bolus.

Study 2: CA reliability – experts at CA also take into account the quality of the swallow sound. SLT’s over detected dysphagia when using CA with a bias towards labelling older adults as dysphagic. SLT’s were able to listen for respiration, voice quality (both 100% correct), duration of swallow (66%) and number of swallows (55%). There was some disagreement between raters (reliability) and some were able to be more specific/ sensitive to sounds.

Pulse Oximetry

Sherman et al 1999, Assessment of dysphagia with the use of pulse oximetry

-        Pulse oximetry measures SPO2, is non-ivasive and gives a realtime output.

-        Aspiration has been shown to decrease oxygen saturation by interfering with alveolar gas exchange. Viscous liquids/ solids will have a greater adverse effect on O2 saturation.

-        Direct aspiration of material may cause reduced air flow to the affected lung tissue and stimulate a reflex bronchospasm, both of which may cause desaturation.

-        During the study modified barium swallow assessments were carried out with pulse oximatory at the same time. A baseline for SP02 was collected over one minute.

-        The study demonstrated a direct correlation between the degree of oxygen desaturation and the severity of swallowing abnormality.

-        Patients who aspirated had a significantly greater decline in SP02 than those who penetrated and cleared or did not aspirate.

-        Pulse oximatry may be useful to differentiate between patients who may be penetrating and clearing material and those who are aspirating.Exclusions: patients receiving O2.

Reflections on the use of Pulse Oximetry and cervical auscultation

Research

Literature reviews for both pulse oximetry and cervical auscultation have shown variable support for the use of these techniques to reliably and consistenly to identify aspiration/ dysphagia.  Although there have been contradicting studies it appears that cervical auscultation and pulse oximetry are useful additions to the clinical swallow exam when not used in isolation. Research suggests that they are useful at giving information on whether or not a swallow is abnormal or that aspiration may be present without being able to confirm why or what type of dysphagia may be present.

Reflection

I have found cervical auscultation useful with patients who are unable to vocalise after swallowing in order to listen to their breathing sounds for any changes in quality. I also find it useful to listen for any abnormal swallow sounds. I find that I am unable to identify clear physiologic swallow sounds e.g. the opening of the UES. I have also found CA useful for patients with COPD to identify their baseline breathing sounds and to help listen to the duration of the apnea period.

I find that pulse oximetry is useful for patient s with whom I would like an extra tool during their swallow examination to help me identify whether they are aspirating or not. I find it useful for patients who may be silently aspirating. The SP02 levels can vary with patients who are not aspirating so I find I look for the timing of any changes as well as the degree of desaturation when interpreting results.