Evaluation of a New Protocol for Adult Procedural Sedation With Ketamine-propofol in a 1 on 4 Ratio

Procedural sedation is the monitored use of sedatives and/or analgesics in a patient who must endure a short painful or frightening procedure, bringing the patient into a sedative state while retaining his spontaneous breathing and respiratory reflexes. Examples of these procedures are cardioversion, repositioning of a shoulder luxation or incision of a skin abscess, and these are frequently performed at the emergency ward. An easy and unambiguous protocol for procedural sedation was composed at the emergency department of the University Hospital of Ghent applicable for nearly all patients and procedures. This protocol included recommendations for necessary monitoring such as continuous electrocardiogram, intermittent blood pressure measurements, oxygen saturation and capnography, as well as safety precautions for standby medications or medical devices for hemodynamic and airway control. As sedative drug a mixture of ketamine and propofol ("ketofol") in a 1 on 4 ratio was selected based on the available literature. Both ketamine and propofol are known to neutralise each other's undesirable effects and ketamine adds an analgesic quality. Ketofol has proven effective and safe in studies and is non-inferior to propofol. Though it is most often used in a 1 on 1 ratio, both pharmacological and clinical studies favour a 1 on 4 ratio. According to the protocol ketofol 1 on 4 was prepared by mixing 1ml of ketamine (50mg) and 20ml of propofol (200mg) in a single syringe and administrated as a loading dose of 1ml/10kg, followed by a stepwise titration in aliquots of 0,5ml/10kg. Above 65 years the loading dose was halved.

An adult patient presenting at the investigating hospital in need of procedural sedation, who agreed the informed consent for procedural sedation was treated according to this protocol. Patients with an American Society of Anesthesiologist physical status classification system status of III or more, with an anticipated difficult airway or intoxicated patients were discussed with the anaesthesiology department to decide the feasibility of sedation in the emergency ward setting. Pregnant patients were excluded.

Associated to this newly implemented protocol, an observational prospective study was associated to verify the safety and effectivity, and to score the physicians satisfaction. A separate informed consent was obtained for participation in the study to permit inclusion of patient and procedural data into a registry. Data was registered by the physician responsible for the sedation in a questionnaire. The investigators hypothesized the protocol with ketofol in a 1 on 4 ratio would be safe and effective and would serve to facilitate procedural sedation by emergency physicians.

Inclusion criteria

• All adult patients presenting to the university hospital of Ghent and in need of procedural sedation as determined by the treating physician, who underwent procedural sedation by the standard protocol using ketofol in a 1 on 4 ratio.

Exclusion criteria

• pregnant patient
• procedural sedation not performed at the emergency department