A review of patient-controlled sedation:

Effects of single-dose pregabalin on postoperative pain in dacryocystorhinostomy surgery

Background

Postoperative pain of dacryocystorhinostomy (DCA) surgery is one of the serious issues to be considered. Administrating opioids to relieve postoperative pain and facing their increasing side effects in eye surgeries, make the use of non-opioid drugs inevitable.

Objectives

The present study examined the efficacy of pregabalin in alleviating the postoperative pain of DCA surgery.

Patients and Methods

The present study has been carried out as a double-blind, randomized clinical trial on the patient candidates for DCR. The patients were randomly divided in to two groups of pregabalin and placebo. Patients in pregabalin group received 300 mg of pregabalin, an hour before the operation in the morning of the surgery. Pain intensity on visual analog scale (VAS) was recorded until 24 hours after the operation; also the rate of administrated opioids and nausea/vomiting frequency were recorded during the first 24-hour period after the operation and the resultsof the two groups were compared.

Results

Postoperative pain intensity in the pregabalin group at the time of recovery was significantly lower than that of the placebo group (P = 0.001) until 24 hours after the surgery. In the pregabalin group 17.5% of the patients received opioids while in the placebo group the figure was 52.5% (P = 0.001). Nausea frequency was also higher in the placebo group than the pregabalin group (P = 0.003).

Conclusions

A single 300 mg dose of pregabalin, an hour before DCA can effectively reduce pain intensity and also reduce opioid dose and nausea/vomiting.

Effect of oral pregabalin premedication on post-operative pain in laparoscopic gastric bypass surgery

Background

Post-operative pain and the administration of opioids to relieve it, is considered to be one of the important issues in surgery wards. This issue is even more significant in obese patients, because of the side effects of opioids. Pregabalin is an analog of gamma aminobutyric acid (GABA) which can be effective in dealing with post-operative pain.

Objectives

This study will consider the effect of oral pregabalin in relieving the pain of obese patients after gastric bypass surgery.

Patients and Methods

In a double blind clinical trial, 60 candidates for laparoscopic gastric bypass surgery were enrolled in the study through convenience and non-random sequential sampling, into two groups; pregabalin group and control group. Inclusion criteria consisted of: morbid obesity with a body mass index (BMI) > 35, age 18–50, American Society of Anesthesiologists (ASA) status I or II, and willingness to take part in the study. Patients in the pregabalin group received 300 mg of oral pregabalin on the morning of the surgery. Post-operative pain was controlled by the patient-controlled intravenous analgesia (PCIA) method, an AutoMed infusion pump containing 20 mg of morphine and normal saline (total volume 100 cc) was administered to all patients after surgery. Patients’ level of pain were compared by considering their pain intensity on a visual analog scale (VAS), and the occurrence of nausea/vomiting from recovery, until 24 hours after surgery.

Results

A total of 60 patients were compared; 30 patients in each of the pregabalin and control groups. Both groups were similar in age and sex distribution. Mean pain intensity levels during the whole follow up were lower in the pregabalin group than in the control group, up to a maximum of 24 hours after the operation (P < 0.001). Incidence of nausea/vomiting was greater in the control group than in the pregabalin group (P < 0.001).

Conclusions

The findings of this study indicate that oral pregabalin (300 mg dose) can alleviate patients’ pain and nausea/vomiting and notably reduce adverse effects.

Patient-maintained propofol sedation: a follow up safety study using a modified system in volunteers

Patient-maintained sedation is a mode of patient-controlled sedation during which propofol is administered using a target-controlled infusion, with patient demand increasing the target concentration. A system tested previously for safety in our institution resulted in oversedation. Aiming to improve safety, we modified the system by increasing the lockout period to 4 min,reducing the starting concentration to 0.5 microg x ml(-1) and the increments on demand to 0.1 microg x ml(-1). As in the previous study, healthy volunteers attempted to render themselves unconscious by frequently pressing the demand button. To assess effects on memory, volunteers were given keywords to remember every 15 min. The maximum target concentration reached varied between 1.0 and 2.5 microg x ml(-1). No volunteers lost consciousness, however, one volunteer had a brief period of apnoea and oxygen desaturation. The Cp50 for loss of memory for words was 1.26 microg x ml(-1). Although this version represents an improvement, we conclude that the system is not yet completely suitable for use without anaesthetic supervision.

[Patient-controlled sedation with propofol for extracorporeal shock wave lithotripsy]

OBJECTIVE

Evaluation of patient-controlled sedation with propofol for extracorporeal shock wave lithotripsy (ESWL) using an EDAP LT01 lithotriptor.

STUDY DESIGN

Prospective clinical study.

PATIENTS

Fifty consecutive patients, ASA I or II, aged 18-65 years.

METHODS

Patients received 50 mg of propofol five minutes before ESWL, then they self-administered 50 mg bolus doses of propofol with a ten minutes lock-out interval. Pain (1-100 mm VAS) and sedation (four points scale) were assessed every five minutes. Patient satisfaction was recorded at the end of the procedure. Pharmacokinetic simulation was done with the Marsh's data set.

RESULTS

Three patients were excluded. Patients received a mean propofol dose of 147 +/- 68 mg during the procedure with a mean duration of 47 +/- 8 minutes. The median of the higher sedation scores was 2 (drowsy) and mean maximal VAS was 40 +/- 20 mm (10-70). No complications were recorded. Thirty-nine patients (83%) were satisfied or very satisfied by patient-controlled sedation.

CONCLUSION

Patient-controlled sedation with propofol is a safe and efficient mode of administration of an hypnotic agent for ESWL.

Patient-controlled versus anesthesiologist-controlled conscious sedation with propofol for dental treatment in anxious patients

In a randomized, cross-over study, we prospectively compared the efficacy and quality of two methods to achieve conscious sedation with propofol in 11 unpremedicated, anxious dental patients. Each patient underwent two dental procedures, one that was conducted under target-controlled infusion (TCI) by the anesthesiologist (ACS), and the other that used patient-controlled sedation (PCS). The initial target concentration in the ACS mode was 2.5 microg/mL, which was manipulated in both directions until the desired clinical end point was achieved. In the PCS mode, a 4-mg bolus of propofol (10 mg/mL) was delivered at each activation of the machine, infused over 7 s without a lockout interval. The anxious dental patients could induce and maintain conscious sedation with the PCS settings. The mean (range) venous blood propofol concentrations were not significantly different with either mode: ACS 1.8 (0.8-2.7) microg/mL and PCS 1.2 (0.2-2.5) microg/mL. The level of patient satisfaction, quality of sedation, and treatability were not different for either mode of sedation. The intensity of amnesia for intraoperative events was related to the blood concentrations achieved. In the ACS mode, one patient became unresponsive (sedation level 4) immediately after the start of sedation. No adverse cardiorespiratory effects resulted from either mode of propofol sedation. Five patients expressed a strong preference for PCS, and three would prefer ACS in the future. The results of the present study suggest that with these PCS settings, a satisfactory level of conscious sedation and a high level of patient satisfaction was achieved.

IMPLICATIONS

In a randomized, cross-over study, the blood propofol concentrations necessary to achieve conscious sedation in anxious dental patients using a target-controlled infusion conducted by the anesthesiologist versus patient-controlled sedation were not different. With the patient-controlled sedation settings, a satisfactory level of conscious sedation and a high level of patient satisfaction were achieved.