Anesthetist Controlled Versus Patient-controlled Sedation: Risks and Benefits
Condition: Patient Satisfaction
Study type: Interventional
Phase: Phase 1

Summary: 
      Perioperative anxiety has many hazards and should be eliminated. Patients undergoing
      ophthalmologic procedures often undergo it under local anesthesia. In a trial to improve
      patients' satisfaction sedation is given. Sedation could be given either by an anesthetist or
      patient-controlled methods. This study compared both methods of sedation in terms of safety,
      depth of sedation, and patient satisfaction.
    

Detailed description: 
      This randomized controlled trial was conducted in Kasr Al Ainy Hospital, Ophthalmology
      surgeries operation theatre, Cairo University, Cairo, Egypt.

      After the approval of the research ethical committee (approval number MD-18-2019) & obtaining
      written informed consent from every patient, 30 patients belonging to the American society of
      anesthesiologists (ASA) status I, II, aging from 40 to 65 years old, both genders,
      co-operative patients aware of the instructions, scheduled for cataract surgery under local
      anesthesia were enrolled for this randomized controlled trial.

      However, patients with a diagnosis of cognitive impairment or mental disorder,
      hypersensitivity to any of the used drugs, having any conditions contraindicating local
      anesthesia (e.g. Coagulation disorders) were excluded from the study.

      Furthermore, patients having severe pulmonary disease e.g. (obstructive sleep apnea),
      patients using sedative medications within the previous month, and patients with chronic
      renal and cardiac disorder (e.g. chronic renal failure, heart failure) were also excluded
      from the study.

      Patients were randomly assigned into two equal groups of 15 patients each, the anesthetist
      controlled group Ga (n=15) and the patient-controlled group Gp (n=15). Randomization was done
      using computer-generated numbers and the allocation sequence of the participants was
      concealed in sequentially numbered sealed opaque envelopes.

      In the anesthetist controlled group Ga (n=15):

      Routine preoperative assessment (proper history taking, examination, and laboratory
      investigations) was done to all patients as needed.

      In the preoperative preparation room, intravenous access (20 gauge cannula) was obtained,
      premedications were given in the form of (Granitryl at a dose of 10 mcg/kg as an antiemetic
      and ranitidine at a dose of 0.2 mg/kg as antistress ulcer prophylaxis, they were given
      diluted with 0.9% sodium chloride solution over 10 minutes), 15 minutes before giving the
      local anesthesia. Then patients were transferred to the operating room.

      In the operating room, all patients were monitored with continuous pulse oximetry,
      electrocardiogram, and non-invasive blood pressure measured at 10 minutes interval (the blood
      pressure cuff was applied on the contralateral side of the IV cannula), and oxygen support
      was given through nasal cannula applied near the nostrils at a flow of 5 liters per minute.

      The IV sedation was started before the administration of the local anesthesia in the form of
      a bolus of 0.02 mg/kg of midazolam and 0.2 mcg/kg of fentanyl to all patients.

      Then further doses were given as needed through the procedure according to the depth of
      sedation. The depth of sedation was assessed at regular intervals (every 10 minutes) using
      the sedation scale.

      A depth of sedation level II or III on the sedation scale was targeted, level I was
      considered anxious and needs further doses, and more than level III was considered a risk of
      oversedation.

      A soluset was filled with a mixture of 10 mg of midazolam and 150 mcg of fentanyl diluted
      with 0.9 % sodium chloride solution to complete a total volume of 50 ml. and a concentration
      of 0.2 mg/ml of midazolam and 3 mcg/ml of fentanyl.

      The anesthetist withdrew 2 ml from the soluset and gave them to the patient according to
      depth of sedation.

      In the patient-controlled group Gp (n=15):

      Routine preoperative assessment (proper history taking, examination, and laboratory
      investigations) was done to all patients as needed.

      In the preoperative preparation room, intravenous access (20 gauge cannula) was obtained,
      premedications were given in the form of (Granitryl at a dose of 10 mcg/kg as an antiemetic
      and ranitidine at a dose of 0.2 mg/kg as antistress ulcer prophylaxis, they were given
      diluted with 0.9% sodium chloride solution over 10 minutes), 15 minutes before giving the
      local anesthesia. Then patients were transferred to the operating room.

      In the operating room, all patients were monitored with continuous pulse oximetry,
      electrocardiogram, and non-invasive blood pressure measured at 10 minutes interval (the blood
      pressure cuff was applied on the contralateral side of the IV cannula), and oxygen support
      was given through nasal cannula applied near the nostrils at a flow of 5 liters per minute.

      The IV sedation was started before the administration of the local anesthesia in the form of
      a bolus of 0.02 mg/kg of midazolam and 0.2 mcg/kg of fentanyl to all patients.

      Patients were instructed on how to use the PCS pump, then the pump (Accufuser) was connected
      to the IV cannula, patients were given the press button of the infusion pump in one hand and
      a clicker in the other hand.

      Patients were instructed to press the button as often as they feel the need to do so, as
      there was a lockout interval of six minutes to limit the amount of medication, during this
      interval the pump will not deliver drugs regardless of the patient's attempts to press the
      button. The attending anesthetist was instructed to respond to the patient's question "how
      often should I press the button" with the answer "when you feel unsedated, anxious,
      irritable, not calm, afraid of the operation and you want to be more relaxed and calm just
      press the button". If the patient pressed the button during the permission time (after the 6
      min lock-out interval), a 2 ml infusion of the drug mixture was administered IV, Otherwise,
      no drug was administered to the patient.

      In this group, patients received a clicker, on the other hand, to press on both the pump and
      clicker together, every time he/she used the pump to denote the number of attempts.

      The observing anesthetist present beside the patient used a stopwatch to record the time from
      the start of the use of the pump, and the number of the attempts that were recorded as the
      number of the clicks done by the patient, and so in that way the anesthetist differentiated a
      true attempt from a false one done during the lockout interval that was fixed at 6 minutes.

      The PCS pump was of 100 ml volume, of 2 ml demand doses, 6 minutes lockout interval and of no
      basal rate of infusion, it was filled with a mixture of 10 mg of midazolam and 150 mcg of
      fentanyl diluted with 0.9 % sodium chloride solution to complete a total volume of 50 ml. and
      a concentration of 0.2 mg/ml of midazolam and 3 mcg/ml of fentanyl.

      A demand dose of 2 ml with 6 minutes lockout time was used. The patient was unaware of the
      lockout period, the attending anesthetist was aware of the drug regimen to be present to
      intervene for adverse events.

      Instruction on the use of commercially available PCS pump was given verbally by the
      anesthetist on the day of surgery and reinforced again in the operation room (OR).

      A depth of sedation level II or III on the sedation scale was targeted, level I was
      considered anxious and needs further doses, and more than level III was considered a risk of
      oversedation.

      In both groups:

      The eye to be operated on was marked prior to starting the local anesthesia. The total volume
      of 8 ml was prepared for the peribulbar block including a mixture of 4 ml lidocaine 2%, 4 ml
      bupivacaine 0.5%, and 75 IU of hyaluronidase. The anesthetic solution was injected into the
      extraconal compartment of the eye using two 23 gauge needles with 5 ml being injected at the
      junction of outer one-third and inner two-thirds of the lower orbital rim and 3 ml were
      injected superonasally beneath the superior orbital notch. The success of the block was
      assessed by globe bulge, loss of ocular movements and the eye was padded 5 to 10 minutes
      (with intermittent pressing 5 seconds and relieve the press for 10 seconds) to enhance the
      spread of the anesthetic solution and prevent a rise in the intraocular pressure.

      After adequate and complete muscle paralysis (assessed by the inability to move the eye in 6
      directions known as a gaze), the surgical procedure was allowed by an expert surgeon.

      Heart rate, blood pressure, arterial oxygen saturation, and respiratory rate were recorded as
      a baseline before sedation and at 10 minutes intervals.

      Patients' and surgeons' satisfaction, depth of sedation, and patients' anxiety were assessed.

      The OR was equipped with emergency equipment and drugs. All the equipment necessary for
      transformation to general anesthesia if needed at any point were also present including
      (analgesic, hypnotic, muscle relaxant, laryngoscope, different endotracheal tube sizes a
      supraglottic device, and a well-functioning anesthesia machine). This transformation would
      have been needed if a safety endpoint was reached.

      Safety endpoints for anesthetist intervention included arterial desaturation < 90%, for more
      than one minute, hypotension < 90 mmHg systolic or 20% decrease from baseline persisting when
      repeating determination one minute later, inability to tolerate the procedure, oversedation,
      airway obstruction, and the need for general anesthesia where the anesthetist will intervene.

      At the end of the procedure, the total amount of sedating drug administered was recorded, as
      well as the number of attempts of self-administration was recorded before discharge from the
      OR. The patient was transferred to the recovery room and the time to ambulation was
      calculated, before being discharged to the ward safely.
    

Intervention name(s): Midazolam-Fentanyl combination
Intervention type(s): Drug
Intervention description(s): Sedation is given to patients undergoing cataract surgery under local anesthesia
Intervention MeSH terms: Midazolam; Fentanyl
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Double (Participant, Outcomes Assessor)
Primary purpose: Supportive Care
Keywords: PCS