Medial open transversus abdominis plane (MOTAP) catheters for analgesia following open liver resection: study protocol for a randomized controlled trial

Background: The current standard for pain control following liver surgery is intravenous, patient-controlled analgesia (IV PCA) or epidural analgesia. We have developed a modification of a regional technique called medial open transversus abdominis plane (MOTAP) catheter analgesia. The MOTAP technique involves surgically placed catheters through the open surgical site into a plane between the internal oblique muscle and the transverse abdominis muscle superiorly. The objective of this trial is to assess the efficacy of this technique. Methods/design: This protocol describes a multicentre, prospective, blinded, randomized controlled trial. One hundred and twenty patients scheduled for open liver resection through a subcostal incision will be enrolled. All patients will have two MOTAP catheters placed at the conclusion of surgery. Patients will be randomized to one of two parallel groups: experimental (local anaesthetic through MOTAP catheters) or placebo (normal saline through MOTAP catheters). Both groups will also receive IV PCA. The primary endpoint is mean cumulative postoperative opioid consumption over the first 2 postoperative days (48 hours). Secondary outcomes include pain intensity, patient functional outcomes, and the incidence of complications. Discussion: This trial has been approved by the ethics boards at participating centres and is currently enrolling patients. Data collection will be completed by the end of 2014 with analysis mid-2015 and publication by the end of 2015. Trial registration: The study is registered with http://clinicaltrials.gov (NCT01960049; 23 September 2013)This research is supported by the Innovation Fund of the Alternative Funding Plan from the Academic Health Sciences Centres of Ontario

The Use of Air in the Inspired Gas Mixture During Two-Lung Ventilation Delays Lung Collapse During One-Lung Ventilation

BACKGROUND: Collapse of the ipsilateral lung facilitates surgical exposure during thoracic procedures. The use of different gas mixtures during two-lung ventilation (2LV) may improve or impede surgical conditions during subsequent one-lung ventilation (OLV) by increasing or delaying lung collapse. We investigated the effects of three different gas mixtures during 2LV on lung collapse and oxygenation during subsequent OLV: Air/Oxygen (fraction of inspired oxygen [Fio2] = 0.4), Nitrous Oxide/Oxygen (“N2O,” Fio2 = 0.4) and Oxygen (“O2,” Fio2 = 1.0). METHODS: Subjects were randomized into three groups: Air/Oxygen (n = 33), N2O (n = 34) or O2 (n = 33) and received the designated gas mixture during induction and until the start of OLV. Subjects’ lungs in all groups were then ventilated with Fio2 = 1.0 during OLV. The surgeons, who were blinded to the randomization, evaluated the lung deflation using a verbal rating scale at 10 and 20 min after the start of OLV. Serial arterial blood gases were performed before anesthesia induction, during 2LV, and every 5 min, for 30 min, after initiation of OLV. RESULTS: The use of air in the inspired gas mixture during 2LV led to delayed lung deflation during OLV, whereas N2O improved lung collapse. Arterial oxygenation was significantly improved in the O2 group only for the first 10 min of OLV, after which there were no differences in mean Pao2 values among groups. CONCLUSIONS: De-nitrogenation of the lung during 2LV is a useful strategy to improve surgical conditions during OLV. The use of Fio2 1.0 or N2O/O2 (Fio2 0.4) during 2LV did not have an adverse effect on subsequent oxygenation during OLV. IMPLICATIONS: In thoracic anesthesia, the use of air/oxygen mixtures during two-lung ventilation causes a delay in the collapse of the nonventilated lung during subsequent one-lung ventilation, and this interferes with surgical exposure in the chest

Gabapentin reduces preoperative anxiety and pain catastrophizing in highly anxious patients prior to major surgery: a blinded randomized placebo-controlled trial

Gabapentin is increasingly being used for the treatment of postoperative pain and a variety of psychiatric diseases, including chronic anxiety disorders. Trials have reported mixed results when gabapentin has been administered for the treatment of preoperative anxiety. We tested the hypothesis that gabapentin 1,200 mg vs placebo would reduce preoperative anxiety in patients who exhibit moderate to high preoperative anxiety. Methods. A blinded randomized controlled trial was conducted from September 2009 to June 2011 at the Toronto General Hospital. Following ethics approval and informed consent, 50 female patients with a 0-10 numeric rating scale (NRS) anxiety score of greater than or equal to 5/10 consented to receive either gabapentin 1,200 mg (n = 25) or placebo (n = 25) prior to surgery. Randomization was computer generated, and the Investigational Pharmacy was responsible for the blinding and dispensing of medication. All patients and care providers, including physicians, nurses, and study personnel, were blinded to group allocation. Before administering the study medication, baseline anxiety levels were measured using a NRS, the Spielberger State-Trait Anxiety Inventories, the Pain Catastrophizing Scale, and the Pain Anxiety Symptoms Scale-20. Baseline pain intensity (0-10 NRS) and level of sedation (0-10 NRS and Richmond Agitation-Sedation Scale [RASS]) were also measured. Two hours after the administration of gabapentin or placebo (prior to surgery), patients again rated their anxiety, pain, and sedation levels using the same measurement tools as at baseline. The main outcome was a reduction in preoperative anxiety. Results. Forty-four patients (22 treated with gabapentin 1,200 mg and 22 treated with placebo) were included in the analysis of the primary outcome. Analysis of covariance in which pre-drug NRS anxiety scores were used as the covariate showed that post-drug preoperative NRS anxiety (Effect size, 1.44; confidence interval [CI] 0.19 to 2.70) and pain catastrophizing (Effect size, 0.43; CI 0.12 to 0.74) scores were significantly lower in the gabapentin group than in the placebo control group, respectively. Post-drug sedation (Effect size, -3.02; CI -4.28 to -1.77) and RASS (Effect size, 0.41; CI 0.12 to 0.71) scores were significantly higher in the gabapentin group than in the placebo group, respectively. Conclusions. Administration of gabapentin 1,200 mg prior to surgery reduces preoperative NRS anxiety scores and pain catastrophizing scores and increases sedation prior to entering the operating room. These results suggest that gabapentin 1,200 mg may be a treatment option for patients who exhibit high levels of preoperative anxiety and pain catastrophizing; however, the sedative properties of the medication and the possibility of delayed postoperative discharge in the elective ambulatory population need to be considered.Hance Clarke is supported by a Canadian Institutes of Health Research PhD Fellowship Award and by a Merit Award from the Department of Anesthesia at the University of Toronto. Joel Katz is supported by a Canada Research Chair in Health Psychology at York University

Medial open transversus abdominis plane (MOTAP) catheters for analgesia following open liver resection: study protocol for a randomized controlled trial

Abstract Background The current standard for pain control following liver surgery is intravenous, patient-controlled analgesia (IV PCA) or epidural analgesia. We have developed a modification of a regional technique called medial open transversus abdominis plane (MOTAP) catheter analgesia. The MOTAP technique involves surgically placed catheters through the open surgical site into a plane between the internal oblique muscle and the transverse abdominis muscle superiorly. The objective of this trial is to assess the efficacy of this technique. Methods/design This protocol describes a multicentre, prospective, blinded, randomized controlled trial. One hundred and twenty patients scheduled for open liver resection through a subcostal incision will be enrolled. All patients will have two MOTAP catheters placed at the conclusion of surgery. Patients will be randomized to one of two parallel groups: experimental (local anaesthetic through MOTAP catheters) or placebo (normal saline through MOTAP catheters). Both groups will also receive IV PCA. The primary endpoint is mean cumulative postoperative opioid consumption over the first 2 postoperative days (48 hours). Secondary outcomes include pain intensity, patient functional outcomes, and the incidence of complications. Discussion This trial has been approved by the ethics boards at participating centres and is currently enrolling patients. Data collection will be completed by the end of 2014 with analysis mid-2015 and publication by the end of 2015. Trial registration The study is registered with http://clinicaltrials.gov ( NCT01960049 ; 23 September 2013