Propofol is a commonly used anaesthetic for inducing general anaesthesia. Pain on propofol injection is distressing and is one of the limitations of its use. Propofol is a phenol compound, which irritates nerve endings on the venous endothelium to produce immediate pain, whereas delayed pain is mediated by the release of bradykinin. Bradykinin causes vasodilation and increases venous permeability, thereby facilitating contact of the aqueous phase of propofol with nerve endings. Delayed pain occurs 10-20 seconds after injection.~Various methods have been tried so far to reduce pain on propofol injection. A commonly used technique is lignocaine either as pre-treatment or mixed with propofol. Other methods include the use of butorphanol, ondansetron, metoclopramide, opioid, or thiopentone. Propofol injection into a large vein, pre-injection cooling, or warming of propofol have also been investigated.~The Valsalva manoeuvre is a physiological technique, used in the reduction of pain associated with several procedures. The Valsalva manoeuvre alleviates both the somatic and psychological aspects of painful procedures.~Dexmedetomidine is an alpha-2 adrenoceptor agonist that has analgesic and sedative properties, it has been evaluated for reducing the incidence and intensity of propofol-induced pain, but reported results are inconsistent.~in this study, investigators will study the effect of Valsalva manoeuvre as compared with dexmedetomidine injection in reducing the pain associated with propofol injection in upper gastrointestinal endoscopies.
No previous study has cited the use of the Valsalva manoeuvre for the reduction of pain on propofol injection in comparison with dexmedetomidine injection. Therefore, investigators plan a study to evaluate the analgesic efficacy of the Valsalva manoeuvre in alleviating pain during propofol injection as compared to dexmedetomidine injection.