Eric Noll

Enhanced-reality video fluorescence: a real-time assessment of intestinal viability.

Objective:Our aim was to evaluate a fluorescence-based enhanced-reality system to assess intestinal viability in a laparoscopic mesenteric ischemia model. Materials and Methods:A small bowel loop was exposed, and 3 to 4 mesenteric vessels were clipped in 6 pigs. Indocyanine green (ICG) was administered intravenously 15 minutes later. The bowel was illuminated with an incoherent light source laparoscope (D-light-P, KarlStorz). The ICG fluorescence signal was analyzed with Ad Hoc imaging software (VR-RENDER), which provides a digital perfusion cartography that was superimposed to the intraoperative laparoscopic image [augmented reality (AR) synthesis]. Five regions of interest (ROIs) were marked under AR guidance (1, 2a-2b, 3a-3b corresponding to the ischemic, marginal, and vascularized zones, respectively). One hour later, capillary blood samples were obtained by puncturing the bowel serosa at the identified ROIs and lactates were measured using the EDGE analyzer. A surgical biopsy of each intestinal ROI was sent for mitochondrial respiratory rate assessment and for metabolites quantification. Results:Mean capillary lactate levels were 3.98 (SD = 1.91) versus 1.05 (SD = 0.46) versus 0.74 (SD = 0.34) mmol/L at ROI 1 versus 2a-2b (P = 0.0001) versus 3a-3b (P = 0.0001), respectively. Mean maximal mitochondrial respiratory rate was 104.4 (±21.58) pmolO2/second/mg at the ROI 1 versus 191.1 ± 14.48 (2b, P = 0.03) versus 180.4 ± 16.71 (3a, P = 0.02) versus 199.2 ± 25.21 (3b, P = 0.02). Alanine, choline, ethanolamine, glucose, lactate, myoinositol, phosphocholine, sylloinositol, and valine showed statistically significant different concentrations between ischemic and nonischemic segments. Conclusions:Fluorescence-based AR may effectively detect the boundary between the ischemic and the vascularized zones in this experimental model.

Intraperitoneal ropivacaine nebulization for pain management after laparoscopic cholecystectomy: a comparison with intraperitoneal instillation

BACKGROUND: Studies evaluating intraperitoneal local anesthetic instillation for pain relief after laparoscopic procedures have reported conflicting results. In this randomized, double-blind study we assessed the effects of intraperitoneal local anesthetic nebulization on pain relief after laparoscopic cholecystectomy. METHODS: Patients undergoing elective laparoscopic cholecystectomy were randomly assigned to receive either instillation of ropivacaine 0.5%, 20 mL after induction of the pneumoperitoneum, or nebulization of ropivacaine 1%, 3 mL before and after surgery. Anesthetic and surgical techniques were standardized. Degree of pain at rest and on deep breathing, incidence of shoulder pain, morphine consumption, unassisted walking time, and postoperative nausea and vomiting were evaluated at 6, 24, and 48 hours after surgery. RESULTS: Of the 60 patients included, 3 exclusions occurred for conversion to open surgery. There were no differences between groups in pain scores or in morphine consumption. No patients in the nebulization group presented significant shoulder pain in comparison with 83% of patients in the instillation group (absolute risk reduction −83, 95% CI −97 to −70, P < 0.001). Nineteen (70%) patients receiving nebulization walked without assistance within 12 hours after surgery in comparison with 14 (47%) patients receiving instillation (absolute risk reduction −24, 95% CI −48 to 1, P = 0.04). One (3%) patient in the instillation group vomited in comparison with 6 (22%) patients in the nebulization group (absolute risk reduction −19%, 95% CI −36 to −2, P = 0.03). CONCLUSIONS: Intraperitoneal ropivacaine nebulization was associated with reduced shoulder pain and unassisted walking time but with an increased incidence of postoperative vomiting after laparoscopic cholecystectomy.

The assessment of the quality of the graft in an animal model for lung transplantation using the metabolomics 1H high-resolution magic angle spinning NMR spectroscopy

Standards are needed to control the quality of the lungs from nonheart‐beating donors as potential grafts. This was here assessed using the metabolomics 1H high‐resolution magic angle spinning NMR spectroscopy. Selective perfusion of the porcine bilung block was set up 30 min after cardiac arrest with cold Perfadex®. Lung alterations were analyzed at 3, 6, and 8 h of cold ischemia as compared to baseline and to nonperfused lung. Metabolomics analysis of lung biopsies allowed identification of 35 metabolites. Levels of the majority of the metabolites increased over time at 4°C without perfusion, indicating cellular degradation, whereas levels of glutathione decreased. When lung was perfused at 4°C, levels of the majority of the metabolites remained stable, including levels of glutathione. Levels of uracil by contrast showed a reverse profile, as its signal increased over time in the absence of perfusion while being totally absent in perfused samples. Our results showed glutathione and uracil as potential biomarkers for the quality of the lung. The metabolomics 1H high‐resolution magic angle spinning NMR spectroscopy can be efficiently applied for the assessment of the quality of the lung as an original technique characterized by a rapid assessment of intact biopsy samples without extraction and can be implemented in hospital environment. Magn Reson Med, 2012.

Prehospital shock index and pulse pressure/heart rate ratio to predict massive transfusion after severe trauma: Retrospective analysis of a large regional trauma database

BACKGROUND Early and accurate detection of severe hemorrhage is critical for a timely trigger of massive transfusion (MT). Hemodynamic indices combining heart rate (HR) and either systolic (shock index [SI]) or pulse pressure (PP) (PP/HR ratio) have been shown to track blood loss during hemorrhage. The present study assessed the accuracy of prehospital SI and PP/HR ratio to predict subsequent MT, using the gray-zone approach. METHODS This was a retrospective analysis (January 1, 2009, to December 31, 2011) of a prospectively developed trauma registry (TRENAU), in which the triage scheme combines patient severity and hospital facilities. Thresholds for MT were defined as either classic (≥10 red blood cell units within the first 24 hours [MT1]) or critical (≥3 red blood cells within the first hour [MT2]). The receiver operating characteristic curves and gray zones were defined for SI and PP/HR ratio to predict MT1 and MT2 and faced with initial triage scheme. RESULTS The TRENAU registry included 3,689 trauma patients, of which 2,557 had complete chart recovery and 176 (6.9%) required MT. In the whole population, PP/HR ratio and SI moderately and similarly predicted MT1 (area under the receiver operating characteristic curve, 0.77 [95% confidence interval {CI}, 0.70–0.84] and 0.80 [95% CI, 0.74–0.87], respectively, p = 0.064) and MT2 (0.71 [95% CI, 0.67–0.76] and 0.72 [95% CI, 0.68–0.77], respectively, p = 0.48). The proportions of patients in the gray zone for PP/HR ratio and SI were 61% versus 40%, respectively, to predict MT1 (p < 0.001) and 62% versus 71%, respectively, to predict MT2 (p < 0.001). In the least severe patient, both indices had fair accuracy to predict MT1 (0.91 [95% CI, 0.82–1.00] vs. 0.87 [95% CI, 0.79–1.00]; p = 0.638), and PP/HR ratio outperformed SI to predict MT2 (0.72 [95% CI, 0.59–0.84] vs. 0.54 [95% CI, 0.33–0.74]; p < 0.015). CONCLUSIONS In an unselected trauma population, prehospital SI and PP/HR ratio were moderately accurate in predicting MT. In the seemingly least severe patients, an improvement of prehospital undertriage for MT may be gained by using the PP/HR ratio. LEVEL OF EVIDENCE Epidemiolgic study, level III.

Metabolism-Guided Bowel Resection Potential Role and Accuracy of Instant Capillary Lactates to Identify the Optimal Resection Site

Background. Strip-based handheld devices can measure lactatemia on capillary blood obtained by needle puncturing. We aimed to assess the kinetic of bowel capillary lactates, metabolomics profiling, and mitochondria respiratory rate in a prolonged model of bowel hypoperfusion. Materials and Methods. In 6 pigs, a 3- to 4-cm ischemic segment was created in 6 small bowel loops (total = 36 loops) by clamping the vascular supply, for a duration of 1 to 6 hours. Hourly, 5 blood samples were obtained by puncturing the serosa, and lactates were measured using a handheld analyzer. Samples were made at the following regions of interest (ROIs): center of the ischemic area (1), proximal and distal clinical margins of resection (2a-2b), and vascularized zones (3a-3b). Every hour, surgical biopsies of ROIs were sampled. Activity of bowel mitochondria complexes was measured after 1, 3, and 5 hours of ischemia. Quantification of metabolites was performed on all samples (total N = 180). Results. Capillary lactates were significantly higher at ROI 1 versus ROI 3ab at all time points. After 1 hour lactates at the margins were significantly higher than those at vascularized areas (P = .0095), showing a mismatch between visual assessment and actual perfusion status. From 2 to 6 hours, there was no difference in lactates between ROIs 2a-2b and 3a-3b. Maximal tissue respiration decreased significantly after 1 hour (ROI 1 vs ROI 3ab). Seven metabolites (lactate, glucose, aspartate, choline, creatine, taurine, and tyrosine) expressed significantly different evolutions between ROIs. Conclusions. Capillary lactates could help precisely estimate local bowel perfusion status.

Cold ischemia with selective anterograde in situ pulmonary perfusion preserves gas exchange and mitochondrial homeostasis and curbs inflammation in an experimental model of donation after cardiac death

The aim of this study was to assess the functional preservation of the lung graft with anterograde lung perfusion in a model of donation after cardiac death. Thirty minutes after cardiac arrest, in situ anterograde selective pulmonary cold perfusion was started in six swine. The alveolo‐capillary membrane was challenged at 3, 6, and 8 h with measurements of the mean pulmonary arterial pressure (mPAP), the pulmonary vascular resistance (PVR), the PaO2/FiO2 ratio, the transpulmonary oxygen output (tpVO2), and the transpulmonary CO2 clearance (tpCO2). Mitochondrial homeostasis was investigated by measuring maximal oxidative capacity (Vmax) and the coupling of phosphorylation to oxidation (ACR, acceptor control ratio) in lung biopsies. Inflammation and induction of primary immune response were assessed by measurement of tumor necrosis factor alpha (TNFα), interleukine‐6 (IL‐6) and receptor for advanced glycation endproducts (RAGE) in bronchoalveolar lavage fluid. Data were compared using repeated measures Anova. Pulmonary hemodynamics (mPAP: P = 0.69; PVR: P = 0.46), oxygenation (PaO2/FiO2: P = 0.56; tpVO2: P = 0.46), CO2 diffusion (tpCO2: P = 0.24), mitochondrial homeostasis (Vmax: P = 0.42; ACR: P = 0.8), and RAGE concentrations (P = 0.24) did not significantly change up to 8 h after cardiac arrest. TNFα and IL‐6 were undetectable. Unaffected pulmonary hemodynamics, sustained oxygen and carbon dioxide diffusion, preserved mitochondrial homeostasis, and lack of inflammation suggest a long‐lasting functional preservation of the graft with selective anterograde in situ pulmonary perfusion.

Isoflurane anesthesia preserves liver and lung mitochondrial oxidative capacity after gut ischemia-reperfusion.

BACKGROUND: Lung and liver dysfunction is involved in gut ischemia–reperfusion (IR)–induced multiple organ failure. We compared the effects of ketamine and isoflurane on liver and lung mitochondrial oxidative capacity after gut IR. METHODS: Adult male Wistar rats were randomized into 4 groups (controls and gut IR receiving either intraperitoneal ketamine or inhaled isoflurane). Maximal oxygen consumption and the activity of respiratory chain complexes were measured on isolated liver and lung mitochondria. RESULTS: Gut IR significantly impaired liver and lung mitochondrial oxidative capacity when using ketamine but not isoflurane. CONCLUSIONS: Isoflurane preserved liver and lung mitochondrial oxidative capacity after gut IR.

Contamination of the laryngoscope handle: an overlooked issue.

In this issue of the European Journal of Anaesthesiology, Howell et al. address the problem of cross-contamination in the operating room associated with the use of nondisposable anaesthesia devices, particularly reusable laryngoscope handles. These authors need to be commended for attracting our attention to a very practical but largely overlooked issue and a simple means of improving patients’ security.

Comparative analysis of resuscitation using human serum albumin and crystalloids or 130/0.4 hydroxyethyl starch and crystalloids on skeletal muscle metabolic profile during experimental haemorrhagic shock in swine: A randomised experimental study.

BACKGROUND Protection against acute skeletal muscle metabolic dysfunction and oxidative stress could be a therapeutic target in volume expansion for severely bleeding patients. OBJECTIVES This experimental pilot study in swine aims at comparing 130/0.4 hydroxyethyl starch (HES) with 4% albumin along with crystalloid perfusion for first-line volume expansion in haemorrhagic shock with a particular emphasis on oxidative stress and muscular mitochondrial function. DESIGN Randomised experimental study. SETTING Digestive Cancer Research Institute Preclinical Laboratory, Strasbourg University Hospital, France, from February 2012 to June 2013. ANIMALS Twenty large white pigs. INTERVENTION Pressure-controlled haemorrhagic shock and volume resuscitation using either 4% human serum albumin or 130/0.4 HES along with crystalloid perfusion were performed in 20 large white pigs. MAIN OUTCOME MEASURES Muscular biopsy of gastrocnemius muscle was performed for metabolomics screening, mitochondrial respiratory chain assessment and electron spin resonance reactive oxygen species production along with arterial and venous reactive oxygen species production at baseline, at the completion of shock, at 90 min and at 180 min after volume expansion. RESULTS There was no difference between the two groups in measurements of skeletal muscle superoxide production. In a pooled analysis, there was a statistically significant decrease in gastrocnemius muscle creatine content from baseline to 90 min (P < 0.05) and 180 min (P < 0.05). Muscular lactate content and mitochondrial respiratory chain oxidative capacity remained constant at the respective time points. CONCLUSION In this pilot experimental study in swine, during pressure-controlled haemorrhagic shock treated with either albumin or 130/0.4 HES in conjunction with crystalloid perfusion, skeletal muscle metabolic profile was unaltered. ETHICAL APPROVAL NUMBER 38.2012.01.031.

Prevention of laparoscopic surgery induced hypothermia with warmed humidified insufflation: Is the experimental combination of a warming blanket synergistic?

Introduction Maintaining normothermia during anesthesia is imperative to provide quality patient care and to prevent adverse outcomes. Prolonged laparoscopic procedures have been identified as a potential risk factor for hypothermia, due to continuous insufflation of cold and dry carbon dioxide. Perioperative hypothermia is associated with increased hospital cost and many complications including; impaired drug metabolism, impaired immune function, cardiac morbidity, shivering, coagulopathy. Methods In this experimental study, four pigs underwent four interventions each, resulting in 16 total trials. Using standardized general anesthesia in a randomized Latin-square sequence the four interventions include: 1. Control group without an administered pneumoperitoneum, 2. Administered standard pneumoperitoneum using 21°C insufflated gas and under-body forced-air warming, 3. Administered pneumoperitoneum with insufflation of warmed/humidified carbon dioxide, 4. Administered pneumoperitoneum with insufflation of warmed/humidified carbon dioxide and under-body forced-air warming. The primary outcome was distal esophageal temperature change 4 hours after trocar insertion. Results Four hours after trocar insertion, pigs in the control group lost 2.1 ± 0.4°C; pigs with warmed and humidified insufflation lost 1.8 ± 0.4°C; pigs with forced-air warming group lost 1.3 ± 0.9°C; and pigs exposed to a combination of warmed and humidified insufflation with forced-air warming increased by 0.3 ± 0.2°C. Conclusion This experimental animal study provides evidence that a combination of warmed and humidified insufflation of carbon dioxide (CO2) in conjunction with forced-air warming is an effective strategy in the prevention of perioperative hypothermia. Further clinical trials investigating humans are therefore indicated.