Inadvertent perioperative hypothermia, defined as a core temperature below 36°C , is a common, yet widely under-acknowledged adverse clinical consequence of surgery [1–3]. Patients undergoing arthroscopic shoulder surgery are particularly at risk, with the average patient experiencing a core temperature heat loss of between 1°C and 3°C [4–6]. Three principle factors are said to contribute to this problem: Reduced metabolic heat production due to the anaesthetic; heat loss due to the cold perioperative environment and the use of large quantities of surgical irrigation solution; and impaired thermoregulation which results in a core to periphery thermal redistribution .
Although hypothermia is a common perioperative problem, it is not a benign one: The consequences are both physiological and psychological in nature and are far more serious than patients just ‘feeling uncomfortably cold’. Research has demonstrated a clear link between inadvertent perioperative hypothermia and serious adverse complications including myocardial ischaemia, surgical site infection, and coagulopathy [1, 8–11]. A person’s temperature is also an integral component of their overall perception of well-being and research has shown that memories of thermal discomfort during the perioperative period significantly affect a patient’s surgical experience [12, 13]. These physiological and psychological adverse effects can, and do, result in prolonged recovery times, lengthier hospital stays, and increased resource use which in turn translates into greater overall healthcare costs [10, 11].
A number of active and passive interventions are recommended in the evidence-based guidelines for maintaining normothermia in perioperative patients [1, 14]. Two relatively simple and inexpensive interventions which are not routinely used on patients undergoing shoulder arthroscopy surgery are preoperative warming using a forced air warming device and the use of warmed intraoperative irrigation solutions .
The preoperative warming of patients at high risk of hypothermia, such as those having arthroscopic surgery, is recommended in evidence-based guidelines [1, 14]. Warming the peripheral tissues preoperatively reduces the impact of core to periphery thermal redistribution caused by anaesthetic-induced peripheral vasodilatation . Consequently, patients experience less post-induction temperature loss and recover from any loss at a faster rate intraoperatively [16–19]. A forced air warming device has been shown to be the most effective method for preoperative warming, consistently demonstrating higher core temperatures in preoperative normothermic patients compared to other warming techniques [17, 19–23].
Warmed intraoperative irrigation solutions
It is well documented that the use of room temperature irrigation solution increases the risk of inadvertent perioperative hypothermia during arthroscopic surgery. A systematic review of 13 randomised controlled trials including 686 patients showed that room-temperature irrigation fluid caused a greater drop in core body temperature and more episodes of hypothermia in patients, than warmed irrigation fluid . There is a significant correlation between the volume of room temperature irrigation solution used and a patients’ mean postoperative temperature [6, 24]. The use of warmed solution for intraoperative irrigation during arthroscopic surgery has been recommended as a method for preventing perioperative hypothermia [1, 4, 14].
There is clear evidence that these two interventions assist in the maintenance of perioperative normothermia but there is now a call for robust well designed research to demonstrate improved clinical outcomes associated with their use . This trial will study the effects of these warming interventions on outcomes of particular interest to perioperative nurses, namely, post-operative temperature, thermal comfort, and total recovery time.
To investigate the effect of preoperative forced air warming and warmed intraoperative irrigation solution, alone and in combination, on postoperative temperature, thermal comfort, and total recovery time in adult patients undergoing elective arthroscopic shoulder surgery.