Perioperative truncal peripheral nerve blocks for bariatric surgery: an opioid reduction strategy.

BACKGROUND: Bariatric surgical patients are vulnerable to cardiopulmonary depressant effects of opioids. The enhanced recovery after surgery (ERAS) protocol to improve postoperative morbidity recommends regional anesthesia for postoperative pain management. However, there is limited evidence that peripheral nerve blocks (PNB) have added benefit. OBJECTIVE: Study the effect of PNB on postoperative pain and opioid use following bariatric surgery. SETTING: Academic medical center, United States. METHODS: We conducted a cohort study of patients who underwent sleeve gastrectomy (SG) or Roux-en-Y gastric bypass (RYGB) surgery. A total of 44 patients received the control ERAS protocol with preoperative oral extended-release morphine sulfate (MS), while 45 patients underwent a PNB with either intrathecal morphine (IM) or oral MS per local ERAS protocol. The PNB group either underwent preoperative bilateral T7 paravertebral (PVT) PNBs (27 patients) with IM or postoperative transversus abdominis plane (TAP) PNBs (18 patients) with oral MS. The primary outcome compared total opioid consumption between the ERAS control group and the PNB group up to 48 hours postoperatively. Secondary outcomes included comparison by block type and postoperative pain scores. RESULTS: PVT or TAP PNB patients had a reduction in mean postoperative oral morphine equivalent (OME) requirements compared with the ERAS protocol cohort at 24 hours (93.9 versus 42.8 mg), P < .0001; at 48 hours (72.6 versus 40.5 mg); and in pain scores at 24 hours (5.64/10 versus 4.46/10), P = .02. OME and pain scores were higher in the SG cohort. CONCLUSION: Addition of truncal PNB to standard ERAS protocol for bariatric surgical patients reduces postoperative total opioid consumption.

Metabolic engineering of thermophilic Bacillus licheniformis for chiral pure D-2,3-butanediol production.

2,3-Butanediol is an important compound that can be used in many areas, especially as a platform chemical and liquid fuel. But traditional 2,3-butanediol producing microorganisms, such as Klebsiella pneumonia and K. xoytoca, are pathogens and they can only ferment sugars at 37°C. Here, we reported a newly developed Bacillus licheniformis. A protoplast transformation system was developed and optimized for this organism. With this transformation method, a marker-less gene deletion protocol was successfully used to knock out the ldh gene of B. licheniformis BL1 and BL3. BL1 was isolated earlier from soil for lactate production and it was further evolved to BL3 for xylose utilization. Combined with pH and aeration control, ldh mutant BL5 and BL8 can efficiently ferment glucose and xylose to D-(-) 2,3-butanediol at 50°C, pH 5.0. For glucose and xylose, the specific 2,3-butanediol productivities are 29.4 and 26.1 mM/h, respectively. The yield is 0.73 mol/mol for BL8 in xylose and 0.9 mol/mol for BL5 and BL8 in glucose. The D-(-) 2,3-butanediol optical purity is more than 98%. As far as we know, this is the first reported high temperature butanediol producer to match the simultaneous saccharification and fermentation conditions. Therefore, it has potential to further lower butanediol producing cost with low cost lignocellulosic biomass in the near future.

Isolation, characterization and evolution of a new thermophilic Bacillus licheniformis for lactic acid production in mineral salts medium.

The high fermentation cost of lactic acid is a barrier for polylactic acid (PLA) to compete with the petrochemical derived plastics. In order to lower the cost of lactic acid, the industry needs a microorganism that can ferment various sugars at high temperature (50°C) and at the same time using low cost mineral salts (MS) medium. One such bacterium, BL1, was isolated at 50°C and identified as Bacillus licheniformis. BL1 can ferment glucose to optically pure l-lactate with a maximum specific productivity of 7.8 g/hl in LB medium and 0.7 g/hl in MS medium at 50°C. BL1 can also consume 10% and 15% glucose in 20 and 48 h, respectively. After serial transfer of BL1 and BL2 in different concentrations of xylose and MS medium respectively, the final mutant BL3 could efficiently ferment glucose and xylose with specific productivity of 1.9 g/hl and 1.2g/hl in strict MS medium.