Patient-Controlled Sedation in Port Implantation (PACSPI-2)

The study is an open multicentre randomized controlled trial with a study and a control arm in a 1:1 ratio. Patients will be randomized to either a control arm of LA for SVP-implantation or a study arm of PCS with propofol and alfentanil as adjunct to LA for SVP-implantation. The aim is to randomize 340 patients with an estimated patient recruitment over 18 months with a following 6 months of data cleaning and analysis. The trial will be performed at two centres; County Hospital Ryhov, Jönköping, Sweden and University Hospital Linköping, Sweden. SVP implantation procedure and perioperative time period is estimated to 2-4 hours. The primary endpoint is assessment of patients´ self-reported pain perception. Secondary outcomes include patient satisfaction, implantation conditions, sedation level, sedative and analgesic medication consumption, procedural time consumption as well as safety aspects, adverse events and estimation of perioperative experience. Participation in the trial ends after telephone inquiry one day postoperatively.

Control arm:

SVP-implantation in LA:

Subcutanous venous ports were introduced in 1981. A SVP is a small device around 3cm in diameter with an injectable membrane buried just under the skin. It is connected to a thin tube with its tip in a large bore vein. Access to the SVP is achieved by puncturing the skin with a needle.

Local anaesthetic causes the absence of pain sensation in the location where applied by decreasing the rate of depolarization and repolarization of excitable membranes such as nociceptors and nerves. The most commonly used solutions are from the amide group differing in pharmacokinetics. In order to reduce a burning sensation on infiltration substances can be combined with sodium bicarbonate. There will be no restrictions in the choice of LA-solution being left up to local practice at participating sites. With the beginning of the procedure LA is subcutaneously applied to patients in both groups. LA used at participating centres are Mepivacaine 10mg/ml, 20-40ml subcutaneously or Lidnocaine 10mg/ml, 20-40 ml subcutaneously.

Study arm:

SVP-implantation in LA and PCS:

In addition to LA, patients in the study group are able to self-administer a combination of propofol and alfentanil using a patient-controlled sedation pump. The pump enables the patient via a hand-held button to trigger the release of a single bolus of 0.5ml containing 4.5mg propofol and 25µg alfentanil under an 10 second period. This results in a maximal possible amount of 6 bolus doses per minute.

Propofol is a short-acting anaesthetic agent commonly used for general anaesthesia and procedural sedation. Several mechanisms of action have been proposed both through potentiation of GABAA receptor activity and in higher doses behaving as GABAA receptor agonist. When used for intravenous sedation a single dose wears off within minutes demanding for continuous or intermittent application.

Alfentanil is a short-acting synthetic opioid analgesic agent with rapid onset of effects at µ-opioid receptors. These properties make it suitable to provide analgesia for brief procedures and to infuse for longer procedures and yet provide relatively rapid recovery.

Rescue sedation will be available to patients in both groups on the patient´s or operator´s demand. Rescue sedation consists of propofol and alfentanil administered by the clinician and is documented in the e-CRF.

Setting:

This trial will be carried out in the following anaesthesia departments:

OP/IVA clinic, County Hospital Ryhov, Sweden AnOpIVA clinic, University Hospital Linköping, Sweden

Participants will be instructed on use of the PCS pump (Syramed µSP6000, Arcomed AG, Switzerland) by a nurse anesthetist. The syringe is loaded with 36 ml propofol (10 mg/ml) and 4 ml alfentanil (0.5 mg/ml). Each time the patient presses the handheld button, an aliquot of 0.5 ml is injected (4.5 mg propofol/0.025 mg alfentanil). The injection time is set to 10 s, restricting self-administration to a maximum of 6 bolus doses per minute corresponding to 27 mg propofol and 0.15 mg alfentanil per minute. No lockout period is applied. Local anaesthesia is injected in the operating site. Vital parameters prior to the procedure are recorded. Patients are monitored using electrocardiography for heartrate (HR), non-invasive blood pressure (BP), oxygen saturation (SpO2), and respiratory rate (RR) at 5-min intervals during the procedure. Bradycardia is defined as HR <40 beats/min, tachycardia as HR >100 beats/min, hypotension as systolic BP < 90 mmHg or a decrease of >30% from baseline, hypoxia as SpO2 <90% or a decrease of >5% from baseline, and bradypnea as RR of <8 breaths per minute. Supplemental oxygen via a capnograph-fitted nasal cannula is administered to all patients at 2 L/min during the procedure. The Observer's Assessment of Alertness/Sedation score (OAA/S) [9] is used to determine the sedation level during the four procedural steps: 1) sterile swabbing, 2) injection of LA, 3) catheter tunneling, and 4) sterile drape removal. The operating anesthesiologist assesses the operating conditions on a 4 point scale with 1 enabling the operator to perform the procedure without time delay and 4 having to abort the procedure. Puncture attempt is defined as continuous needle advancement to establish vein puncture. An unvalidated patient perception assessment tool with seven dimensions applying the NRS is used to evaluate patient perception. QoR-15 will be measured att 3 timepoints. Preoperatively, postoperatively before patient discharge and one day postoperatively.

QoR- 15 data sampling was planned a priori to the trial start of PACSPI 2. QoR-15 data was listed as secondary outcome in the protocol and on clinicaltrials.gov. After study commencement we became aware of the importance of not only reporting overall QoR-15 score but even recovery time trajectories for the separate time periods within the allocated groups. Moreover, since QoR-15 is a composite score, positive scores in some domains may be counterbalanced by negative scores in other domains, therefore reporting an aggregate score may cause loss of potentially important, more granular data. To specifically address these questions, we will conduct a pre-planned substudy addressing the trajectories of recovery and domain by domain changes.