A Sensory Stimulation Protocol to Modulate Cough Sensitivity: A Randomized Controlled Trial Safety Study.

Purpose This study evaluated the safety and efficacy of a sensory stimulation protocol that was designed to modulate citric acid cough thresholds as a potential treatment for silent aspiration. Method Healthy adults (n = 24) were randomly assigned to one of three sensory stimulation groups: (a) high-intensity ultrasonically nebulized distilled water (UNDW) inhalations (1.6 ml/min); (b) low-intensity UNDW inhalations (0.5 ml/min); and (3) control, 0.9% saline inhalations (1.6 ml/min). Sensory stimulation was delivered once a day, for 4 consecutive days. Citric acid cough thresholds were determined at baseline, Day 3, and Day 5 to evaluate changes in cough sensitivity. Spirometry was undertaken before, during, and after each sensory stimulation session to monitor for bronchoconstriction. Results No participant showed evidence of bronchoconstriction during the sensory stimulation protocol. There was an interaction effect between day and group on suppressed cough thresholds, χ2(4) = 11.32, p = .02. When compared to the control group, there was a decrease in citric acid cough thresholds across Days 1-5 in the high-intensity (-1.8 doubling concentrations, 95% confidence interval [-2.88, -0.72], p = .01) and low-intensity (-1.3 doubling concentrations, 95% confidence interval [-2.4, -0.2], p = .03) UNDW inhalation groups, representing a sensitization effect of UNDW inhalations on cough sensitivity. Conclusions The UNDW sensory stimulation protocol was safe in healthy adults. The findings provide preliminary evidence that UNDW inhalations sensitize laryngeal afferents related to citric acid-induced cough induction. The therapeutic potential of the UNDW sensory stimulation protocol will be explored in patients with reduced cough sensitivity who are at risk of silent aspiration and aspiration pneumonia. Plain Language Summary This study explored the safety and efficacy of a sensory stimulation protocol that was designed to modulate cough sensitivity as a potential treatment for silent aspiration. The study revealed that inhalations of nebulized distilled water were safe and increased cough sensitivity, when compared to control saline inhalations.

A multicentre prospective observational study comparing arterial blood gas values to those obtained by pulse oximeters used in adult patients attending Australian and New Zealand hospitals.

BACKGROUND: Pulse oximetry is widely used in the clinical setting. The purpose of this validation study was to investigate the level of agreement between oxygen saturations measured by pulse oximeter (SpO2) and arterial blood gas (SaO2) in a range of oximeters in clinical use in Australia and New Zealand. METHODS: Paired SpO2 and SaO2 measurements were collected from 400 patients in one Australian and two New Zealand hospitals. The ages of the patients ranged from 18 to 95 years. Bias and limits of agreement were estimated. Sensitivity and specificity for detecting hypoxaemia, defined as SaO2 < 90%, were also estimated. RESULTS: The majority of participants were recruited from the Outpatient, Ward or High Dependency Unit setting. Bias, oximeter-measured minus arterial blood gas-measured oxygen saturation, was - 1.2%, with limits of agreement - 4.4 to 2.0%. SpO2 was at least 4% lower than SaO2 for 10 (2.5%) of the participants and SpO2 was at least 4% higher than the SaO2 in 3 (0.8%) of the participants. None of the participants with a SpO2 ≥ 92% were hypoxaemic, defined as SaO2 < 90%. There were no clinically significant differences in oximetry accuracy in relation to clinical characteristics or oximeter brand. CONCLUSIONS: In the majority of the participants, pulse oximetry was an accurate method to assess SaO2 and had good performance in detecting hypoxaemia. However, in a small proportion of participants, differences between SaO2 and SpO2 could have clinical relevance in terms of patient monitoring and management. A SpO2 ≥ 92% indicates that hypoxaemia, defined as a SaO2 < 90%, is not present. TRIAL REGISTRATION: Australian and New Zealand Clinical Trials Registry (ACTRN12614001257651). Date of registration: 2/12/2014.