Effectiveness of Enzyme Spray Intervention on Thirst Relief in Patients With Endotracheal Intubation.

This study addresses the high prevalence (66%-70%) of thirst among intensive care unit (ICU) patients with endotracheal intubation, a symptom associated with oral mucosal dryness, nil per os (NPO) status, high-flow oxygen therapy, and medication effects. Unrelieved thirst may contribute to anxiety, delirium, and unplanned extubation. Current clinical practices, such as cold water or saline sprays, provide only transient relief and may pose aspiration risks. Enzyme-based saliva substitutes, which mimic natural saliva and stabilize the oral environment, show potential benefits; however, evidence in ICU populations remains limited. A single-blind randomized controlled trial (RCT) will be conducted in an ICU of a medical center in southern Taiwan. Eligible participants are adult patients (≥18 years) with endotracheal intubation expected to exceed 24 hours, a baseline thirst intensity score (NRS-I) ≥3, and the ability to communicate. A total of 76 participants will be recruited and randomly assigned in a 1:1 ratio to either the experimental group (enzyme-based oral spray) or the control group (distilled water spray), using sequentially numbered, opaque, sealed envelopes (SNOSE) to ensure allocation concealment. The intervention will be administered following routine oral care within a standardized time window (13:00-15:00). Both solutions will be prepared in identical opaque spray bottles to maintain blinding. The protocol includes 12 sprays per session (approximately 1.56 mL), delivered to four standardized intraoral sites, with outcomes monitored over a 4-hour period. Primary outcomes include thirst intensity (Numerical Rating Scale-Intensity, NRS-I) and thirst distress (Numerical Rating Scale-Distress, NRS-D), assessed at baseline (T0) and at 30, 60, 120, and 240 minutes post-intervention (T1-T4) by blinded outcome assessors. No biological specimens will be collected; data will be obtained from self-reported measures and electronic medical records, with strict de-identification and secure storage procedures. This study is considered minimal risk. Any adverse events, such as discomfort or choking, will result in immediate discontinuation of the intervention. Data will be analyzed using generalized estimating equations (GEE) to evaluate group, time, and interaction effects. The findings are expected to provide evidence-based guidance for improving thirst management, enhancing patient comfort, and optimizing the quality of critical care nursing.

Research Background Disease Status and Natural Course Thirst is one of the most prevalent and distressing symptoms among patients admitted to intensive care units (ICUs), with a reported prevalence of approximately 66%-70%. Endotracheal intubation causes inhaled air to bypass the upper airway's natural warming and humidification mechanisms, resulting in oral mucosal dryness. In addition, therapeutic fasting (nil per os, NPO), high-flow oxygen therapy, and medication-related adverse effects may further exacerbate thirst, leading to anxiety, feelings of helplessness, and an increased risk of delirium and unplanned extubation. Available Therapeutic Approaches Current clinical practice primarily relies on moistening the lips with cotton swabs, or administering cold water or cold normal saline sprays, which typically provide thirst relief for approximately 30 minutes. Oral moisturizing agents can be categorized into simple moisturizing formulations-most commonly containing carboxymethyl cellulose (CMC)-which aim to simulate salivary viscosity; however, their effects are generally short-lived, lasting approximately 27 ± 25 minutes. Alternatively, direct oral water instillation in intubated patients may increase the risk of aspiration and choking. For patients requiring prolonged intubation or fasting, hydration alone is often insufficient to maintain oral moisture. Enzyme-based saliva substitutes, which mimic the composition of natural saliva and help stabilize the oral microenvironment, have been developed to address these limitations. Although such products are primarily used in patients with radiation-induced xerostomia, their salivary-mimicking properties and moisture-retaining mechanisms suggest potential applicability to other populations, including ICU patients at high risk of oral dryness or prolonged airway maintenance. Further empirical validation in this population is warranted. Prognosis Effective thirst management may reduce physiological stress responses, decrease agitation, improve sleep quality, and enhance overall quality of critical care. \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ 1. Study Objectives Primary Objective To compare the effectiveness of enzyme-based oral spray versus distilled water (DW) spray in alleviating thirst intensity (Numerical Rating Scale-Intensity, NRS-I) and thirst distress (Numerical Rating Scale-Distress, NRS-D) in patients with endotracheal intubation. Secondary Objective To evaluate the duration of the thirst-relieving effect of the enzyme-based oral spray. \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ 2. Study Design <!-- --> 1. Study Type and Design Framework This study adopts a single-blind randomized controlled trial (RCT) design to compare the effects of enzyme-based oral spray and distilled water (DW) spray on thirst relief among intubated ICU patients. The intervention is conducted based on routine clinical o trial.show_full_description

Inclusion Criteria: * Adult patients aged ≥18 years admitted to the intensive care unit (ICU) with endotracheal intubation, and an expected duration of intubation \>24 hours. * Thirst intensity score ≥3 on the Numerical Rating Scale for Thirst Intensity (NRS-I). * Conscious and able to communicate subjective sensations verbally (Mandarin or Taiwanese) or in written form. * Richmond Agitation-Sedation Scale (RASS) score between -1 and +1. * Willingness to participate and provision of written informed consent after a full explanation of the study. Exclusion Criteria: * Known allergy to enzyme spray components (e.g., lysozyme, lactoperoxidase, glucanase, xylitol). * Known allergy to milk or eggs. * Pre-existing xerostomia. * Presence of oral mucosal ulcers or active oral bleeding. * History of oral surgery. * Physician-diagnosed abnormal salivary secretion. * Physician-determined increased risk of aspiration or other complications associated with oral spray administration.