Effect of reverse Trendelenburg position and positive pressure ventilation on safe non-hypoxic apnea period in obese, a randomized-control trial.

PURPOSE: There is an elevated incidence of hypoxemia during the airway management of the morbidly obese. We aimed to assess whether optimizing body position and ventilation during pre-oxygenation allow a longer safe non-hypoxic apnea period (SNHAP). METHODS: Fifty morbidly obese patients were recruited and randomized for this study. Patients were positioned and preoxygenated for three minutes in the ramp position associated with spontaneous breathing without additional CPAP or PEEP (RP/ZEEP group) or in the reverse Trendelenburg position associated with pressure support ventilation mode with pressure support of 8 cmH2O and an additional 10 cmH2O of PEEP while breathing spontaneously (RT/PPV group) according to randomization. RESULTS: The SNHAP was significantly longer in the RT/PPV group (258.2 (55.1) vs. 216.7 (42.3) seconds, p = 0.005). The RT/PPV group was also associated to a shorter time to obtain a fractional end-tidal oxygen concentration (FEtO2) of 0.90 (85.1(47.8) vs 145.3(40.8) seconds, p < 0.0001), a higher proportion of patients that reached the satisfactory FEtO2 of 0.90 (21/24, 88% vs. 13/24, 54%, p = 0.024), a higher FEtO2 during preoxygenation (0.91(0.05) vs. 0.89(0.01), p = 0.003) and a faster return to 97% oxygen saturation after ventilation resumption (69.8 (24.2) vs. 91.4 (39.2) seconds, p = 0.038). CONCLUSION: In the morbidly obese population, RT/PPV, compared to RP/ZEEP, lengthens the SNHAP, decreases the time to obtain optimal preoxygenation conditions, and allows a faster resuming of secure oxygen saturation. The former combination allows a more significant margin of time for endotracheal intubation and minimizes the risk of hypoxemia in this highly vulnerable population. TRIAL REGISTRATION: NCT02590406, 29/10/2015.

Double-lumen endotracheal tubes and bronchial blockers exhibit similar lung collapse physiology during lung isolation.

PURPOSE: Double-lumen endotracheal tubes (DL-ETT) and bronchial blockers (BB) are frequently used to allow one-lung ventilation (OLV) during video-assisted thoracic surgery (VATS). Recently, faster lung collapse has been documented with a BB than with a DL-ETT. The physiologic mechanisms behind this faster collapse remained unknown. We aimed to measure ambient air absorption (Vresorb) and intra-bronchial pressure (Pairway) into the non-ventilated lung during OLV using DL-ETT and BB. METHODS: Patients undergoing VATS and OLV for lung resection were randomly assigned to have measurements made of Vresorb or Pairway within the non-ventilated lung using either a DL-ETT or BB. RESULTS: Thirty-nine patients were included in the analyses. The mean (standard error of the mean [SEM]) Vresorb was similar in the DL-ETT and BB groups [504 (85) vs 630 (86) mL, respectively; mean difference, 126; 95% confidence interval [CI], -128 to 380; P = 0.31]. The mean (SEM) Pairway became progressively negative in the non-ventilated lung in both the DL-ETT and the BB groups reaching [-20 (5) and -31 (10) cmH2O, respectively; mean difference, -11; 95% CI, -34 to 12; P = 0.44] at the time of the pleural opening. CONCLUSIONS: During OLV before pleural opening, entrainment of ambient air into the non-ventilated lung occurs when the lumen of the lung isolation device is kept open. This phenomenon is prevented by occluding the lumen of the isolation device before pleural opening, resulting in a progressive build-up of negative pressure in the non-ventilated lung. Future clinical studies are needed to confirm these physiologic results and their impact on lung collapse and operative outcomes. TRIAL REGISTRATION: www.clinicaltrials.gov (NCT02919267); registered 28 September 2016.

RéSUMé: OBJECTIF: Les tubes endotrachéaux à double lumière (TET-DL) et les bloqueurs bronchiques (BB) sont fréquemment utilisés pour l'isolation pulmonaire pendant une chirurgie thoracique assistée par vidéoscopie. Récemment, un affaissement pulmonaire plus rapide avec un BB qu'avec un TET-DL a été documenté. Les mécanismes physiologiques derrière cet affaissement plus rapide demeurent inconnus. Notre objectif était de mesurer l'absorption de l'air ambiant (Vresorb) et la pression intra-bronchique (Paérienne) dans le poumon non ventilé pendant la ventilation à un poumon en utilisant un TET-DL et un BB. MéTHODE: Les patients subissant une chirurgie thoracique assistée par vidéoscopie et recevant une ventilation unipulmonaire à l'aide d'un TET-DL ou d'un BB pour une résection pulmonaire ont été aléatoirement assignés à des mesures de Vresorb ou Paérienne dans le poumon non ventilé. RéSULTATS: Trente-neuf patients ont été inclus dans les analyses. La Vresorb moyenne (erreur-type sur la moyenne) était similaire dans les groupes TET-DL et BB [504 (85) vs 630 (86) mL, respectivement; différence moyenne, 126; intervalle de confiance [IC] 95 %, -128 à 380; P = 0,31]. La Paérienne moyenne (erreur-type sur la moyenne) est devenue progressivement négative dans le poumon non ventilé dans les groupes TET-DL et BB en atteignant [-20 (5) et -31 (10) cmH2O, respectivement; différence moyenne, -11; IC 95 %, -34 à 12; P = 0,44] au moment de l'ouverture de la plèvre. CONCLUSION: Pendant la ventilation unipulmonaire avant l'incision de la plèvre, un appel d'air ambiant dans le poumon non ventilé se produit quand la portion du dispositif d'isolation pulmonaire est maintenue ouverte. Ce phénomène peut être évité en occluant la lumière du dispositif d'isolation pulmonaire avant l'ouverture de la plèvre, ce qui entraînera une accumulation progressive de pression négative dans le poumon non ventilé. De futures études cliniques sont nécessaires pour confirmer ces résultats physiologiques et leur impact sur l'affaissement pulmonaire et les devenirs opératoires. ENREGISTREMENT DE L'éTUDE: www.clinicaltrials.gov (NCT02919267); enregistrée le 28 septembre 2016.

Non-ventilated lung deflation during one-lung ventilation with a double-lumen endotracheal tube: a randomized-controlled trial of occluding the non-ventilated endobronchial lumen before pleural opening.

PURPOSE: Lung deflation during one-lung ventilation (OLV) is thought to be faster using a double-lumen endotracheal tube (DL-ETT) than with a bronchial blocker, especially when the non-ventilated lumen is opened to allow egress of air from the operative lung. Nevertheless, ambient air can also be entrained into the non-ventilated lumen before pleural opening and subsequently delay deflation. We therefore hypothesized that occluding the non-ventilated DL-ETT lumen during OLV before pleural opening would prevent air entrainment and consequently enhance operative lung deflation during video-assisted thoracoscopic surgery (VATS). METHODS: Thirty patients undergoing VATS using DL-ETT to allow OLV were randomized to having the lumen of the operative lung either open (control group) or occluded (intervention group) to ambient air. The primary outcome was the time to lung collapse evaluated intraoperatively by the surgeons. The T50, an index of rate of deflation, was also determined from a probabilistic model derived from intraoperative video clips presented in random order to three observers. RESULTS: The median [interquartile range] time to lung deflation occurred faster in the intervention group than in the control group (24 [20-37] min vs 54 [48-68] min, respectively; median difference, 30 min; 95% confidence interval [CI], 14 to 46; P < 0.001). The estimated T50 was 32.6 min in the intervention group compared with 62.3 min in the control group (difference, - 29.7 min; 95% CI, - 51.1 to - 8.4; P = 0.008). CONCLUSION: Operative lung deflation during OLV with a DL-ETT is faster when the operative lumen remains closed before pleural opening thus preventing it from entraining ambient air during the closed chest phase of OLV. TRIAL REGISTRATION: www.clinicaltrials.gov (NCT03508050); registered 27 September 2017.

RéSUMé: OBJECTIF: On pense que la déflation pulmonaire pendant la ventilation unipulmonaire (VUP) est plus rapide à l'aide d'un tube endotrachéal à double lumière (TET-DL) qu'avec un bloqueur bronchique, surtout lorsque la lumière non ventilée est ouverte pour permettre l'évacuation de l'air du poumon opéré. Néanmoins, l'air ambiant peut également être entraîné dans la lumière non ventilée avant l'ouverture pleurale et ainsi retarder la déflation. Nous avons donc émis l'hypothèse que l'occlusion de la lumière non ventilée du TET-DL pendant la VUP avant l'ouverture de la plèvre empêcherait l'entraînement d'air et accélérerait par conséquent la déflation du poumon opéré pendant une chirurgie thoracoscopique vidéo-assistée (VATS). MéTHODE: Trente patients subissant une VATS avec un TET-DL pour permettre une VUP ont été randomisés à une ouverture (groupe témoin) ou à une occlusion (groupe intervention) de la lumière du poumon opéré à l'air ambiant. Le critère d'évaluation principal était le temps jusqu'au collapsus du poumon tel qu'évalué pendant l'opération par les chirurgiens. Le T50, un indice du taux de déflation, a également été déterminé à partir d'un modèle probabiliste dérivé de clips vidéo peropératoires présentés de façon randomisée à trois observateurs. RéSULTATS: Le temps médian [écart interquartile] jusqu'à la déflation du poumon était plus court dans le groupe d'intervention que dans le groupe témoin (24 [20-37] min vs 54 [48-68] min, respectivement; différence médiane, 30 min; intervalle de confiance [IC] à 95 %, 14 à 46; P < 0,001). Le T50 estimé était de 32,6 min dans le groupe d'intervention comparativement à 62,3 min dans le groupe témoin (différence, -29,7 min; IC 95 %, -51,1 à -8,4; P = 0,008). CONCLUSION: La déflation du poumon opéré pendant une VUP avec un TET-DL est plus rapide quand la lumière opératoire reste fermée avant l'ouverture pleurale, l'empêchant ainsi d'entraîner l'air ambiant pendant la phase pré ouverture pleurale de la VUP. ENREGISTREMENT DE L'éTUDE: www.clinicaltrials.gov (NCT03508050); enregistrée le 27 septembre 2017.

Tranexamic Acid in Patients Undergoing Coronary-Artery Surgery.

BACKGROUND: Tranexamic acid reduces the risk of bleeding among patients undergoing cardiac surgery, but it is unclear whether this leads to improved outcomes. Furthermore, there are concerns that tranexamic acid may have prothrombotic and proconvulsant effects. METHODS: In a trial with a 2-by-2 factorial design, we randomly assigned patients who were scheduled to undergo coronary-artery surgery and were at risk for perioperative complications to receive aspirin or placebo and tranexamic acid or placebo. The results of the tranexamic acid comparison are reported here. The primary outcome was a composite of death and thrombotic complications (nonfatal myocardial infarction, stroke, pulmonary embolism, renal failure, or bowel infarction) within 30 days after surgery. RESULTS: Of the 4662 patients who were enrolled and provided consent, 4631 underwent surgery and had available outcomes data; 2311 were assigned to the tranexamic acid group and 2320 to the placebo group. A primary outcome event occurred in 386 patients (16.7%) in the tranexamic acid group and in 420 patients (18.1%) in the placebo group (relative risk, 0.92; 95% confidence interval, 0.81 to 1.05; P=0.22). The total number of units of blood products that were transfused during hospitalization was 4331 in the tranexamic acid group and 7994 in the placebo group (P<0.001). Major hemorrhage or cardiac tamponade leading to reoperation occurred in 1.4% of the patients in the tranexamic acid group and in 2.8% of the patients in the placebo group (P=0.001), and seizures occurred in 0.7% and 0.1%, respectively (P=0.002 by Fisher's exact test). CONCLUSIONS: Among patients undergoing coronary-artery surgery, tranexamic acid was associated with a lower risk of bleeding than was placebo, without a higher risk of death or thrombotic complications within 30 days after surgery. Tranexamic acid was associated with a higher risk of postoperative seizures. (Funded by the Australian National Health and Medical Research Council and others; ATACAS Australia New Zealand Clinical Trials Registry number, ACTRN12605000557639 .).

Stopping vs. Continuing Aspirin before Coronary Artery Surgery.

BACKGROUND: Most patients with coronary artery disease receive aspirin for primary or secondary prevention of myocardial infarction, stroke, and death. Aspirin poses a risk of bleeding in patients undergoing surgery, but it is unclear whether aspirin should be stopped before coronary artery surgery. METHODS: We used a 2-by-2 factorial trial design to randomly assign patients who were scheduled to undergo coronary artery surgery and were at risk for perioperative complications to receive aspirin or placebo and tranexamic acid or placebo. The results of the aspirin trial are reported here. Patients were randomly assigned to receive 100 mg of aspirin or matched placebo preoperatively. The primary outcome was a composite of death and thrombotic complications (nonfatal myocardial infarction, stroke, pulmonary embolism, renal failure, or bowel infarction) within 30 days after surgery. RESULTS: Among 5784 eligible patients, 2100 were enrolled; 1047 were randomly assigned to receive aspirin and 1053 to receive placebo. A primary outcome event occurred in 202 patients in the aspirin group (19.3%) and in 215 patients in the placebo group (20.4%) (relative risk, 0.94; 95% confidence interval, 0.80 to 1.12; P=0.55). Major hemorrhage leading to reoperation occurred in 1.8% of patients in the aspirin group and in 2.1% of patients in the placebo group (P=0.75), and cardiac tamponade occurred at rates of 1.1% and 0.4%, respectively (P=0.08). CONCLUSIONS: Among patients undergoing coronary artery surgery, the administration of preoperative aspirin resulted in neither a lower risk of death or thrombotic complications nor a higher risk of bleeding than that with placebo. (Funded by the Australian National Health and Medical Research Council and others; Australia New Zealand Clinical Trials Registry number, ACTRN12605000557639.).

Right upper lobe anatomy revisited: a computed tomography scan study.

BACKGROUND: The double lumen tube (DLT) has become the most popular way to isolate the lungs for thoracic surgery. The variable anatomy of the right main stem bronchus (RMSB) seems to be the main reason clinicians are unwilling to use the right-sided DLT (R-DLT). The factors that could compromise the adequate ventilation of the right lung are mostly the variable length of the RMSB and the misalignment of the lateral orifice of the R-DLT in regard to the right upper lobe bronchus (RULB). The objectives of this study were to validate an alternative method to estimate the RMSB length, and to determine the distribution of the angulation of the ostium of the RULB. METHODS: From high-resolution computed tomography scans of the thorax of 106 consecutive patients, the length of the RMSB was measured using Kim's method and the carina-to-carina method. The angle between the RULB origin and the lateral aspect of the RMSB was also measured. All these measurements were correlated and inter-observer variation documented. RESULTS: From the Kim's method, the mean (standard deviation [SD]) length of the RMSB was 25.5 (4.7) mm. From the alternative carina-to-carina method, the mean (SD) length of RMSB was 29.4 (4.6) mm. The inter-observer agreement was substantial with both methods (Kim's method: intraclass correlation coefficient [ICC] = 0.84; carina-to-carina method: ICC = 0.95). Both measures were closely related (ICC = 0.93; P < 0.001). The RULB presented a wide range angulation [mean (SD), 0.1 (9.5)°; range, -28.6 to 21.2]. CONCLUSION: These anatomic observations provide a better understanding of the variable anatomy of the right bronchial tree and may guide thoracic anesthesiologists in the choice of the best lung isolation device for their patients.

RéSUMé: CONTEXTE: Le tube double lumière (TDL) est actuellement la modalité la plus populaire pour isoler les poumons lors d'une chirurgie thoracique. L'anatomie variable de la bronche souche droite (BSD) semble être la principale raison qui freine l'engouement des cliniciens à utiliser un TDL droit (TDL-d). Les facteurs pouvant compliquer la ventilation adéquate du poumon droit sont surtout la longueur variable de la BSD et le mauvais alignement entre l'orifice latéral du TDL-d et de la bronche lobaire supérieure droite (BLSD). Les objectifs de cette étude étaient de valider une méthode alternative d'estimation de la longueur de la BSD ainsi que de déterminer la distribution de l'angulation de l'orifice de la BLSD. MéTHODE: En nous basant sur des images de tomodensitométrie (TDM) thoracique haute résolution de 106 patients consécutifs, la longueur de la BSD a été mesurée à l'aide de la méthode de Kim et de la méthode de carène à carène. L'angle entre l'origine de la BLSD et l'aspect latéral de la BSD a également été mesuré. Toutes ces mesures ont ensuite été corrélées et la variation inter-observateur documentée. RéSULTATS: En se fondant sur la méthode de Kim, la longueur moyenne (écart type [ÉT]) de la BSD était de 25,5 (4,7) mm. En se fondant sur la méthode alternative de carène à carène, la longueur moyenne (ÉT) de la BSD était de 29,4 (4,6) mm. La concordance inter-observateur était élevée lors de l'utilisation des deux méthodes (méthode de Kim : coefficient de corrélation intraclasse [CCI] = 0,84; méthode carène à carène : 0,95). Les deux mesures étaient très rapprochées (CCI = 0,93; P < 0,001). La BLSD présentait une angulation très variable [(ÉT) moyen, 0.1 (9,5)°; éventail, -28,6 à 21,2]. CONCLUSION: Ces observations anatomiques nous permettent de mieux comprendre l'anatomie variable de l'arbre bronchique droit et pourrait aider les anesthésiologistes thoraciques à choisir le dispositif le mieux adapté pour isoler le poumon de leur patient.

Comparison of Two Major Perioperative Bleeding Scores for Cardiac Surgery Trials: Universal Definition of Perioperative Bleeding in Cardiac Surgery and European Coronary Artery Bypass Grafting Bleeding Severity Grade.

WHAT WE ALREADY KNOW ABOUT THIS TOPIC: WHAT THIS ARTICLE TELLS US THAT IS NEW: BACKGROUND:: Research into major bleeding during cardiac surgery is challenging due to variability in how it is scored. Two consensus-based clinical scores for major bleeding: the Universal definition of perioperative bleeding and the European Coronary Artery Bypass Graft (E-CABG) bleeding severity grade, were compared in this substudy of the Transfusion Avoidance in Cardiac Surgery (TACS) trial. METHODS: As part of TACS, 7,402 patients underwent cardiac surgery at 12 hospitals from 2014 to 2015. We examined content validity by comparing scored items, construct validity by examining associations with redo and complex procedures, and criterion validity by examining 28-day in-hospital mortality risk across bleeding severity categories. Hierarchical logistic regression models were constructed that incorporated important predictors and categories of bleeding. RESULTS: E-CABG and Universal scores were correlated (Spearman ρ = 0.78, P < 0.0001), but E-CABG classified 910 (12.4%) patients as having more severe bleeding, whereas the Universal score classified 1,729 (23.8%) as more severe. Higher E-CABG and Universal scores were observed in redo and complex procedures. Increasing E-CABG and Universal scores were associated with increased mortality in unadjusted and adjusted analyses. Regression model discrimination based on predictors of perioperative mortality increased with additional inclusion of the Universal score (c-statistic increase from 0.83 to 0.91) or E-CABG (c-statistic increase from 0.83 to 0.92). When other major postoperative complications were added to these models, the association between Universal or E-CABG bleeding with mortality remained. CONCLUSIONS: Although each offers different advantages, both the Universal score and E-CABG performed well in the validity assessments, supporting their use as outcome measures in clinical trials.

Effect of position and positive pressure ventilation on functional residual capacity in morbidly obese patients: a randomized trial.

PURPOSE: In morbidly obese patients, the position and ventilation strategy used during pre-oxygenation influence the safe non-hypoxic apnea time and the functional residual capacity (FRC). In awake morbidly obese volunteers, we hypothesized that the FRC would be higher after a five-minute period of positive pressure ventilation compared with spontaneous ventilation at zero inspiratory pressure. METHODS: Using a prospective crossover randomized trial design, obese subjects underwent, in a randomized order, a combination of one of three positions, supine (S), beach chair (BC), and reverse Trendelenburg (RT), and one of two ventilation strategies, spontaneous ventilation at zero inspiratory pressure (ZEEP-SV) or with positive pressure (PP-SV) set to an inspiratory pressure of 8 cmH2O, positive end-expiratory pressure of 10 cmH2O, and fraction of inspired oxygen of 0.21. RESULTS: Seventeen obese volunteers with a mean (standard deviation; SD) body mass index of 50 (8) kg·m-2 were included. Mean (SD) FRC in the three positions (S, BC, RT) was significantly higher using PP-SV compared with ZEEP-SV [2571 (477) vs 2215 (481) mL, respectively; mean difference, 356; 95% confidence interval (CI), 209 to 502; P < 0.001]. Mean (SD) FRC was significantly higher in the RT compared with BC position [2483 (521) vs 2338 (469) mL, respectively; mean difference, 145; 95% CI, 31 to 404; P = 0.01], while there was no difference between S and BC [2359 (519) mL vs 2338 (469) mL, respectively; mean difference, 21; 95% CI, -93 to 135; P = 0.89]. CONCLUSION: In awake morbidly obese volunteers, an increase in the FRC is observed when spontaneous ventilation at zero inspiratory pressure is switched to positive pressure. Compared with S positioning, the BC position had no measurable impact on the FRC. The RT position resulted in an optimal FRC. TRIAL REGISTRATION: clinicaltrials.gov (NCT02121808). Registered 24 April 2014.

Cerebral Oximetry Monitoring to Maintain Normal Cerebral Oxygen Saturation during High-risk Cardiac Surgery: A Randomized Controlled Feasibility Trial.

BACKGROUND: Cerebral oxygen desaturation during cardiac surgery has been associated with adverse perioperative outcomes. Before a large multicenter randomized controlled trial (RCT) on the impact of preventing desaturations on perioperative outcomes, the authors undertook a randomized prospective, parallel-arm, multicenter feasibility RCT to determine whether an intervention algorithm could prevent desaturations. METHODS: Eight Canadian sites randomized 201 patients between April 2012 and October 2013. The primary outcome was the success rate of reversing cerebral desaturations below 10% relative to baseline in the intervention group. Anesthesiologists were blinded to the cerebral saturation values in the control group. Intensive care unit personnel were blinded to cerebral saturation values for both groups. Secondary outcomes included the area under the curve of cerebral desaturation load, enrolment rates, and a 30-day follow-up for adverse events. RESULTS: Cerebral desaturations occurred in 71 (70%) of the 102 intervention group patients and 56 (57%) of the 99 control group patients (P = 0.04). Reversal was successful in 69 (97%) of the intervention group patients. The mean cerebral desaturation load (SD) in the operating room was smaller for intervention group patients compared with control group patients (104 [217] %.min vs. 398 [869] %.min, mean difference, -294; 95% CI, -562 to -26; P = 0.03). This was also true in the intensive care unit (P = 0.02). There were no differences in adverse events between the groups. CONCLUSIONS: Study sites were successful in reversal of desaturation, patient recruitment, randomization, and follow-up in cardiac surgery, supporting the feasibility of conducting a large multicenter RCT.

Bronchial blocker versus left double-lumen endotracheal tube in video-assisted thoracoscopic surgery: a randomized-controlled trial examining time and quality of lung deflation.

INTRODUCTION: Double-lumen endotracheal tubes (DL-ETT) and bronchial blockers (BB) have both been used for lung isolation in video-assisted thoracic surgery (VATS). Though not well studied, it is widely thought that a DL-ETT provides faster and better quality lung collapse. The aim of this study was to compare a BB technique vs a left-sided DL-ETT strategy with regard to the time and quality of lung collapse during one-lung ventilation (OLV) for elective VATS. METHODS: Forty patients requiring OLV for VATS were randomized to receive a BB (n = 20) or a left-sided DL-ETT (n = 20). The primary endpoint was the time from pleural opening (performed by the surgeon) until complete lung collapse. The time was evaluated offline by reviewing video recorded during the VATS. The quality of lung deflation was also graded offline using a visual scale (1 = no lung collapse; 2 = partial lung collapse; and 3 = total lung collapse) and was recorded at several time points after pleural incision. The surgeon also graded the time to complete lung collapse and quality of lung deflation during the procedure. The surgeon's guess as to which device was used for lung isolation was also recorded. RESULTS: Of the 40 patients enrolled in the study, 20 patients in the DL-ETT group and 18 in the BB group were analyzed. There mean (standard deviation) time to complete lung collapse of the operative lung was significantly faster using the BB compared with using the DL-ETT [7.5 (3.8) min vs 36.6 (29.1) min, respectively; mean difference, 29.1 min; 95% confidence interval, 1.8 to 7.2; P < 0.001]. Overall, a higher proportion of patients in the BB group than in the DL-ETT group achieved a quality of lung collapse score of 3 at five minutes (57% vs 6%, respectively; P < 0.004), ten minutes (73% vs 14%, respectively; P = 0.005), and 20 min (100% vs 25%, respectively; P = 0.002) after opening the pleura. The surgeon incorrectly guessed the type of device used in 78% of the BB group and 50% of the DL-ETT group (P = 0.10). CONCLUSION: The time and quality of lung collapse during OLV for VATS was significantly better when using a BB than when using a left-sided DL-ETT. Surgeons could not reliably determine which device was being used based on the time and quality of lung collapse. This trial was registered at ClinicalTrials.gov number, NCT01615263.

A multicentre randomized-controlled trial of inhaled milrinone in high-risk cardiac surgical patients.

PURPOSE: Inhaled milrinone (iMil) has been used for the treatment of pulmonary hypertension (PH) but its efficacy, safety, and prophylactic effects in facilitating separation from cardiopulmonary bypass (CPB) and preventing right ventricular (RV) dysfunction have not yet been evaluated in a clinical trial. The purpose of this study was to investigate if iMil administered before CPB would be superior to placebo in facilitating separation from CPB. METHODS: High-risk cardiac surgical patients with PH were randomized to receive iMil or placebo after the induction of anesthesia and before CPB. Hemodynamic parameters and RV function were evaluated by means of pulmonary artery catheterization and transesophageal echocardiography. The groups were compared for the primary outcome of the level of difficulty in weaning from CPB. Among the secondary outcomes examined were the reduction in the severity of PH, the incidence of RV failure, and mortality. RESULTS: Of the 124 patients randomized, the mean (standard deviation [SD]) EuroSCORE II was 8.0 (2.6), and the baseline mean (SD) systolic pulmonary artery pressure (SPAP) was 53 (9) mmHg. The use of iMil was associated with increases in cardiac output (P = 0.03) and a reduction in SPAP (P = 0.04) with no systemic hypotension. Nevertheless, there was no difference in the combined incidence of difficult or complex separation from CPB between the iMil and control groups (30% vs 28%, respectively; absolute difference, 2%; 95% confidence interval [CI], -14 to 18; P = 0.78). There was also no difference in RV failure between the iMil and control groups (15% vs 14%, respectively; difference, 1%; 95% CI, -13 to 12; P = 0.94). Mortality was increased in patients with RV failure vs those without (22% vs 2%, respectively; P < 0.001). CONCLUSION: In high-risk cardiac surgery patients with PH, the prophylactic use of iMil was associated with favourable hemodynamic effects that did not translate into improvement of clinically relevant endpoints. This trial was registered at ClinicalTrials.gov; identifier: NCT00819377.

RéSUMé: OBJECTIF: La milrinone inhalée est utilisée pour traiter l'hypertension pulmonaire (HP) mais son efficacité, son innocuité et ses effets prophylactiques pour faciliter le sevrage de la circulation extracorporelle (CEC) et prévenir la dysfonction ventriculaire droite (VD) n'ont pas encore été évalués dans le cadre d'une étude clinique. L'objectif de cette étude était d'examiner si la milrinone inhalée avant la CEC serait supérieure à un placebo pour faciliter le sevrage de la CEC. MéTHODE: Des patients de chirurgie cardiaque à risque élevé et souffrant d'HP ont été randomisés à recevoir de la milrinone inhalée ou un placebo après l'induction de l'anesthésie et avant la CEC. Les paramètres hémodynamiques et la fonction VD ont été évalués à l'aide d'un cathéter de l'artère pulmonaire et d'une échocardiographie transœsophagienne. Les groupes ont été comparés selon notre critère d'évaluation principal, soit le niveau de difficulté du sevrage de la CEC. Parmi les critères d'évaluation secondaires examinés figuraient la réduction de la gravité de l'HP, l'incidence d'insuffisance cardiaque droite et la mortalité. RéSULTATS: Au total, 124 patients ont été randomisés. Le score EuroSCORE II moyen (écart type [ÉT]) était de 8,0 (2,6), et la pression systolique de l'artère pulmonaire moyenne de base (ÉT) était de 53 (9) mmHg. L'utilisation de milrinone inhalée a été associée à des augmentations du débit cardiaque (P = 0,03) et à une réduction de la pression systolique de l'artère pulmonaire (P = 0,04) sans hypotension systémique. Toutefois, aucune différence n'a été observée dans l'incidence combinée de sevrage difficile ou complexe de la CEC entre le groupe milrinone inhalée et le groupe témoin (30 % vs 28 %, respectivement; différence absolue, 2 %; intervalle de confiance [IC] 95 %, −14 à 18; P = 0,78). Aucune différence n'a été observée non plus en matière d'insuffisance cardiaque droite entre le groupe milrinone inhalée et le groupe témoin (15 % vs 14 %, respectivement; différence, 1 %; IC 95 %, −13 à 12; P = 0,94). La mortalité était augmentée chez les patients avec insuffisance cardiaque droite (22 % vs 2 %, respectivement; P < 0.001). CONCLUSION: Chez les patients de chirurgie cardiaque à risque élevé atteints de HP, l'utilisation prophylactique de milrinone inhalée a été associée à des effets hémodynamiques favorables qui ne se sont pas traduits en améliorations des critères pertinents d'un point de vue clinique. Cette étude a été enregistrée au ClinicalTrials.gov; identifiant : NCT00819377.

Prevalence of and risk factors for persistent postoperative nonanginal pain after cardiac surgery: a 2-year prospective multicentre study.

BACKGROUND: Persistent postoperative pain continues to be an underrecognized complication. We examined the prevalence of and risk factors for this type of pain after cardiac surgery. METHODS: We enrolled patients scheduled for coronary artery bypass grafting or valve replacement, or both, from Feb. 8, 2005, to Sept. 1, 2009. Validated measures were used to assess (a) preoperative anxiety and depression, tendency to catastrophize in the face of pain, health-related quality of life and presence of persistent pain; (b) pain intensity and interference in the first postoperative week; and (c) presence and intensity of persistent postoperative pain at 3, 6, 12 and 24 months after surgery. The primary outcome was the presence of persistent postoperative pain during 24 months of follow-up. RESULTS: A total of 1247 patients completed the preoperative assessment. Follow-up retention rates at 3 and 24 months were 84% and 78%, respectively. The prevalence of persistent postoperative pain decreased significantly over time, from 40.1% at 3 months to 22.1% at 6 months, 16.5% at 12 months and 9.5% at 24 months; the pain was rated as moderate to severe in 3.6% at 24 months. Acute postoperative pain predicted both the presence and severity of persistent postoperative pain. The more intense the pain during the first week after surgery and the more it interfered with functioning, the more likely the patients were to report persistent postoperative pain. Pre-existing persistent pain and increased preoperative anxiety also predicted the presence of persistent postoperative pain. INTERPRETATION: Persistent postoperative pain of nonanginal origin after cardiac surgery affected a substantial proportion of the study population. Future research is needed to determine whether interventions to modify certain risk factors, such as preoperative anxiety and the severity of pain before and immediately after surgery, may help to minimize or prevent persistent postoperative pain.

Step-by-step clinical management of one-lung ventilation: continuing professional development.

PURPOSE: The purpose of this Continuing Professional Development Module is to review the issues pertinent to one-lung ventilation (OLV) and to propose a management strategy for ventilation before, during, and after lung isolation. PRINCIPAL FINDINGS: The need for optimal lung isolation has increased with the advent of video-assisted thoracoscopic surgery, as surgical exposure is critical for successful surgery. Continuous positive airway pressure applied to the operative lung or intermittent two-lung ventilation should therefore be avoided if possible. Optimal management of OLV should provide adequate oxygenation and also prevent acute lung injury (ALI), the leading cause of death following lung resection. Research conducted in the last decade suggests implementing a protective ventilation strategy during OLV that consists of small tidal volumes based on ideal body weight, routine use of positive end-expiratory pressure, low inspired oxygen fraction, with low peak and plateau airway pressures. High respiratory rates to compensate for low tidal volumes may predispose to significant air trapping during OLV, so permissive hypercapnea is routinely employed. The management of OLV extends into the period of two-lung ventilation, as the period prior to OLV impacts lung collapse, and both the time before and after OLV influence the extent of ALI. Lung re-expansion at the conclusion of OLV is an important component of ensuring adequate ventilation and oxygenation postoperatively but may be harmful to the lung. CONCLUSIONS: Optimal perioperative care of the thoracic patient includes a protective ventilation strategy from intubation to extubation and into the immediate postoperative period. Anesthetic goals include the prevention of perioperative hypoxemia and postoperative ALI.

Influence of norepinephrine and phenylephrine on frontal lobe oxygenation during cardiopulmonary bypass in patients with diabetes.

OBJECTIVE: Although utilization of vasopressors recently has been associated with reduced cerebral oxygenation, the influence of vasopressors on cerebral oxygenation during cardiopulmonary bypass in patients with diabetes is unknown. The aim of this study was to document the impact of norepinephrine and phenylephrine utilization on cerebral oxygenation in patients with and without diabetes during cardiopulmonary bypass. DESIGN: Prospective, clinical study. SETTING: Academic medical center. PARTICIPANTS: Fourteen patients with diabetes and 17 patients without diabetes undergoing cardiac surgery. INTERVENTIONS: During cardiopulmonary bypass, norepinephrine (diabetics n = 6; non-diabetics n = 8) or phenylephrine (diabetics n = 8; non-diabetics n = 9) was administered intravenously to maintain mean arterial pressure above 60 mmHg. MEASUREMENTS AND MAIN RESULTS: Mean arterial pressure, venous temperature, arterial oxygenation, and frontal lobe oxygenation (monitored by near-infrared spectroscopy) were recorded before anesthesia induction (baseline) and continuously during cardiopulmonary bypass. Frontal lobe oxygenation was lowered to a greater extent in diabetics versus non-diabetics with administration of norepinephrine (-14±13 v 3±12%; p<0.05). There was also a trend towards a greater reduction in cerebral oxygenation in diabetics versus non-diabetics with administration of phenylephrine (-12±8 v -6±7%; p = 0.1) during cardiopulmonary bypass. CONCLUSIONS: Administration of norepinephrine to restore mean arterial pressure during cardiopulmonary bypass is associated with a reduction in frontal lobe oxygenation in diabetics but not in patients without diabetes. Administration of phenylephrine also were associated with a trend towards a greater reduction in frontal lobe oxygenation in diabetics. The clinical implications of these findings deserve future consideration.

Influences of spinal anesthesia on exercise tolerance in patients with chronic obstructive pulmonary disease.

RATIONALE: Lower limb muscle dysfunction contributes to exercise intolerance in chronic obstructive pulmonary disease (COPD). We hypothesized that signaling from lower limb muscle group III/IV sensory afferents to the central motor command could be involved in premature cycling exercise termination in COPD. OBJECTIVES: To evaluate the effects of spinal anesthesia, which presumably inhibited central feedback from the lower limb muscle group III/IV sensory afferents on exercise tolerance and cardiorespiratory response during constant work-rate cycling exercise in patients with COPD. METHODS: In a crossover and double-blind randomized design, eight patients with COPD (FEV(1), 67 ± 8% predicted) completed a constant work-rate cycling exercise after sham (NaCl, interspinous L(3)-L(4)) or active (fentanyl 25 µg, intrathecal L(3)-L(4)) spinal anesthesia. MEASUREMENTS AND MAIN RESULTS: When compared with placebo, endurance time was significantly prolonged after spinal anesthesia with fentanyl (639 ± 87 s vs. 423 ± 38 s [mean ± SEM]; P = 0.01). Ventilation and respiratory rate were reduced at isotime points under the fentanyl condition, whereas ventilatory efficiency and dead space ventilation were improved. Patients exhibited less dynamic hyperinflation at isotime points with spinal anesthesia. Consequently, the rise in dyspnea was significantly flatter during the fentanyl condition than with placebo. CONCLUSIONS: Spinal anesthesia enhanced cycling exercise tolerance in patients with COPD, mostly by reducing ventilatory response and dyspnea during exercise; these effects were possibly mediated through the inhibition of group III/IV lower limb sensory muscle afferents.