Approximately 17.5 million people worldwide die every year because of cardiovascular diseases, including ischemic heart disease, cerebrovascular disease, and rheumatic heart disease (Virani et al., 2020, WHO, 2014). Coronary artery bypass graft surgery is considered a safe and effective treatment option for coronary artery diseases (Bachar and Manna, 2022. Routine mechanical ventilation is used for patients undergoing coronary artery bypass graft surgery under general anaesthesia, and ventilator support is continued in the intensive care unit until patients are hemodynamically stable and their respiratory function normalizes (Bignami et al., 2016). Most patients are extubated within the first 12 h (Martin and Turkelson, 2006, Weissman, 2004).

Postoperatively, patients are susceptible to numerous complications related to general anaesthesia, endotracheal intubation, the surgical procedure itself, and clinical conditions (Drašković and Rakić, 2011). Symptoms associated with these complications include pain, various pulmonary, cardiovascular, and neurological symptoms, impaired hemodynamic stability, anxiety, nausea/vomiting, thirst, insomnia, and general discomfort (Laerkner et al., 2015, Uysal, 2007).

Changes in patients’ physiological parameters may occur for reasons such as the use of cardiopulmonary bypass during surgery, the need for inotropic medication after surgery, and the use of mechanical ventilation to support respiration (Carl et al., 2010, Uhlig et al., 2020). Physiological parameters outside of their normal ranges strain the patient’s body, increase oxygen demand, and may exacerbate their existing condition. This delays postoperative recovery and prolongs hospital stays (Batchelor and Ljungqvist, 2019).

The recent literature has emphasized the significant physical discomfort associated with postoperative complaints such as lack of well-being, dry mouth, and thirst (Schittek et al., 2021a, Schittek et al., 2021c, Schittek et al., 2021b). Although experienced frequently and intensely by patients, these discomforts are overlooked and not given the necessary importance by healthcare professionals (Andrew-Romit and Mortel, 2011, Li et al., 2022, Motta et al., 2020, Tsai et al., 2022). Dry mouth and thirst occur in surgical patients as a result of preoperative stress and fasting, anaesthetic drugs, endotracheal intubation, and fluid loss during surgery, although extending oral restrictions longer than recommended before and after surgery is among other reasons (Aroni et al., 2012, Rızalar et al., 2019). If the symptoms of thirst are not recognized early and managed appropriately, the patient may have increased irritability, dehydration, and other complications (Tsai et al., 2022).

Another of the most common postoperative complaints in patients who undergo surgical interventions under general anaesthesia is nausea and vomiting. The incidence of nausea/vomiting can reach 70–80 % among postoperative patients (Barnes, 2020, Doubravska et al., 2010). Managing nausea and vomiting after cardiovascular surgery accelerates recovery and reduces mortality and morbidity, costs, and lengths of stay in the intensive care unit and hospital (Barnes, 2020, Batchelor and Ljungqvist, 2019). Therefore, oral diet management is recommended to reduce nausea and vomiting, which affects the well-being of the patient in the early postoperative period (Schittek et al., 2021a, Schittek et al., 2021b). It has also been recommended to identify patients at risk of nausea and vomiting, take prophylactic measures, and use combined antiemetic regimens as well as complementary methods (Tang et al., 2003).

Many recent studies have explored ways to increase patient comfort and well-being and to eliminate physical discomfort in the postoperative period (Doi et al., 2021, Li et al., 2022, Schittek et al., 2021a, Schittek et al., 2021b). Interventions to eliminate problems such as thirst, nausea, and vomiting in the early postoperative period improve patients’ physical, psychological, spiritual, environmental, and sociocultural comfort and encourage health-promoting behaviours. Health-promoting behaviours are also reported to be associated with comfort provision (Schittek et al., 2021c, Udayasankar et al., 2020, Wilson and Kolcaba, 2004).

Cold oral stimuli are reported to be effective in the management of postoperative thirst (Tsai et al., 2022). In the literature, studies have demonstrated the use of simple treatments such as mentholated saline popsicles; mentholated chewing gum and lip balm; pure water popsicles and ice chips; iced tea; and oral care to relieve thirst and dry mouth (Aroni et al., 2020, Doi et al., 2021, Garcia et al., 2019, Schittek et al., 2021a, Sebaee and Elhadary, 2017, Serato et al., 2019, VonStein et al., 2019). However, there are no studies evaluating the effect of menthol delivered in the form of oral lozenges on thirst and other parameters in postoperative patients. The present study was conducted to determine the effect of oral menthol lozenges administered to cardiovascular surgery patients after extubation on their postoperative thirst, nausea/vomiting, physiological parameters, and comfort level. Our aim is to help improve efforts to increase patient comfort by providing evidence of the effectiveness of simple, low-cost menthol lozenges in reducing post-extubation thirst, nausea, and vomiting.