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. 2018 Jun 4;2018(6):CD009642. doi: 10.1002/14651858.CD009642.pub3

Zengin 2015.

Methods Randomized, controlled trial. Blinding unclear.
The purpose of this study was to evaluate and compare the effects of preoperative oral pregabalin and perioperative intravenous lidocaine infusion on postoperative morphine requirement, adverse effects, patients’ satisfaction, mobilization, time to first defaecation and time to discharge in patients undergoing laparotomy.
The study was conducted in Turkey between November 2010 and April 2011.
Participants Number assessed for eligibility: N/A
Number randomized: 80→ 20:20:20:20
Number analysed: (80)→ (20):(20):(20):(20) (not clearly stated)
Four groups, two not of interest (pregabalin, pregabalin+ lidocaine)
Inclusion criteria
ASA I and II, 18 to 65 years of age and elective laparotomy
Exclusion criteria
ASA ≥ III, liver or kidney failure, chronic pain, epilepsy or other neurological disease or a history of allergy to one of the study drugs
Baseline details
Experimental group (n = 20)
Mean age (years): 51.1, SD = 26.2
M = 55%, F = 45%
Mean weight (kg): 72.2, SD = 25.5
ASA I/II (n): N/A
Mean duration of anaesthesia (min): N/A
Mean duration of surgery (min): 114.1, SD = ± 89.8
Main surgical procedures (n): laparotomy (20)
Control group (n = 20)
Mean age (years): 53.2, SD = 15.7
M = 50%, F = 50%
Mean weight (kg): 70.0, SD = ± 16.7
ASA I/II (n): N/A
Mean duration of anaesthesia (min): N/A
Mean duration of surgery (min): 101.0, SD = 78.0
Main surgical procedures (n): laparotomy (20)
Interventions Experimental group (20 patients)
Group L (lidocaine) patients ingested placebo capsules 12 hrs before surgery and on the morning of surgery, and received a bolus injection of 1.0 mg/kg lidocaine at induction of anaesthesia, then a continuous infusion with a Braun Perfusor infusion pump at a rate of 2 mg/kg/hr during the operation until skin closure.
Control group (20 patients)
In group C (control‐placebo), patients ingested placebo capsules 12 hrs before the operation and on the morning of the operation, and received saline infusion perioperatively.
Outcomes The primary endpoint of the study was not defined. Power analysis was performed for postoperative morphine requirement.
Dichotomous

  1. Nausea overall

  2. Adverse events (pruritus)


Continuous

  1. Pain at 0, 2, 4, 6, 8, 12, 16, 22, 28, 34, 40, 48 hrs (VAS 0 to 100 mm, mean + SD)

  2. Bowel sound (hrs, mean + SD)

  3. Defecation (hrs, mean + SD)

  4. Length of hospital stay (hrs, mean + SD)

  5. Time to mobilisation (hrs, mean + SD)

  6. PCA morphine consumption (mg, at 4, 34, 40, 48 hrs, mean + SD, not for lidocaine group),

  7. Perioperative MAP (mmHg, mean + SD)

  8. ‐ Perioperative heart rate (beats/min, mean + SD)
Notes

  1. Small trial sample size (< 200 patients), relevant groups: n = 40

  2. Power analysis performed (postoperative morphine requirement, n = 19 per group)


Medication
Postoperatively, intravenous morphine was administered until visual analogue scale (VAS) scores were < 30, and intravenous PCA consisting of 1 mg/ml morphine solution with 1.5 mg bolus dose and 8 min lockout interval was started in the recovery room.
Anaesthesia
The anaesthesia regime was standardized in both groups.
Funding
None.
Risk of bias
Bias Authors' judgement Support for judgement
Random sequence generation (selection bias) Unclear risk Quote: “randomization was performed with sealed envelope method before the day of surgery when patients arrived to the ward reception area.”
It is not clear from the description how the randomization was performed (e. g. shuffling envelopes).
Allocation concealment (selection bias) Unclear risk No statement on allocation concealment.
Blinding of participants and personnel (performance bias) 
 All outcomes Unclear risk Quote: “[…] [T]he present prospective, randomized, placebo‐controlled and double‐blinded study […].”
No explicit statement how participants and personnel were blinded.
Blinding of outcome assessment (detection bias) 
 All outcomes Unclear risk No statement on blinding of outcome assessment.
Incomplete outcome data (attrition bias) 
 All outcomes Unclear risk Dropout rate unclear.
There is no statement as to whether the presented results are for all participants who were randomized.
Selective reporting (reporting bias) Unclear risk There is no reference to a trial registry or study protocol.
Other bias Low risk The study appears to be free of other sources of bias.

Acronyms and abbreviations used in these tables

ASA = American Society of Anesthesiologists Physical Status, BMI = body mass index, BP = blood pressure, CABG = coronary artery bypass grafting, CPB = cardiopulmonary bypass, CRP = C‐reactive protein, cTnI = cardiac troponin I, F = female, hrs= hours, ICU = intensive care unit, IL = interleukin, IM = intramuscular, IP = intraperitoneal; IQR = interquartile range, IV = intravenous, LOCF = last observation carried forward, LVEF = left ventricular ejection fraction, M = male, MAP = mean arterial pressure, mins = minutes, MWD = minute‐walk distance, n = number of participants, N/A = not available, NRS = normal rating scale, NSAID = non‐steroid anti‐inflammatory drug, PACU = postanaesthesia care unit, PCA = patient‐controlled analgesia, PCEA = patient‐controlled epidural analgesia, pm = afternoon, POD = postoperative day, PONV = postoperative nausea and vomiting, PO/PR = by mouth/by rectum, PRN = as needed, QoR = Quality of Recovery; SD = standard deviation, SE = standard error, SEM = standard error of mean, SNOSE = sequentially numbered opaque sealed envelopes, TAP = transverse abdominal plane, TEA = thoracic epidural analgesia, Tnl = troponin I, VAS = visual analogue scale, VRS = verbal rating scale, yrs = years, IL‐1RA = Interleukin 1 receptor antagonist