Cognitive Aids for the Management of Thoracic Anesthesia Emergencies: Consensus Guidelines on Behalf of a Canadian Thoracic Taskforce.

A cognitive aid is a tool used to help people accurately and efficiently perform actions. Similarly themed cognitive aids may be collated into a manual to provide relevant information for a specific context (eg, operating room emergencies). Expert content and design are paramount to facilitate the utility of a cognitive aid, especially during a crisis when accessible memory may be limited and distractions may impair task completion. A cognitive aid does not represent a rigid approach to problem-solving or a replacement for decision-making. Successful cognitive aid implementation requires dedicated training, access, and culture integration. Here the authors present a set of evidence-based cognitive aids for thoracic anesthesia emergencies developed by a Canadian thoracic taskforce.

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.

Current trends in anesthesia for esophagectomy.

PURPOSE OF REVIEW: Despite marked improvements in perioperative outcomes, esophagectomy continues to be a high-risk operation associated with significant morbidity and mortality. Progress has been achieved through evidence-based changes in preoperative optimization, intraoperative ventilation strategies, fluid therapy, and analgesia, as well as expedited postoperative recovery pathways. This review will summarize the recent literature on the anesthetic management of patients undergoing esophageal resection. RECENT FINDINGS: The current focus in publications on the perioperative management of esophagectomy patients can be summarized under the umbrella term of enhanced recovery pathways, focusing on ventilation, fluid therapy, analgesia and minimally invasive surgical approaches. Lung protective ventilation reduces pulmonary complications in cases requiring one-lung ventilation. Excess fluid administration contributes to morbidity while restrictive approaches have not resulted in an increased risk of acute kidney injury. Goal-directed fluid therapy remains intuitive yet unproven. Thoracic epidural analgesia reduces the systemic inflammatory response, pulmonary complications, and enhances postoperative pain control, yet if causing perioperative hypotension may be associated with anastomotic leaks. Enhanced recovery pathways have facilitated low morbidity and mortality rates in a high-risk population but are heterogeneous and limited by a weak evidence base. Minimally invasive surgical approaches are increasingly popular and appear to have at least equivalent outcomes to open procedures. SUMMARY: The morbidity and mortality after esophagectomy remains high despite significant improvements over the last decades. Enhanced recovery pathways appear promising in achieving further marginal gains but at present are lacking large scale, prospective, multicenter evidence.

Lung Injury After One-Lung Ventilation: A Review of the Pathophysiologic Mechanisms Affecting the Ventilated and the Collapsed Lung.

Lung injury is the leading cause of death after thoracic surgery. Initially recognized after pneumonectomy, it has since been described after any period of 1-lung ventilation (OLV), even in the absence of lung resection. Overhydration and high tidal volumes were thought to be responsible at various points; however, it is now recognized that the pathophysiology is more complex and multifactorial. All causative mechanisms known to trigger ventilator-induced lung injury have been described in the OLV setting. The ventilated lung is exposed to high strain secondary to large, nonphysiologic tidal volumes and loss of the normal functional residual capacity. In addition, the ventilated lung experiences oxidative stress, as well as capillary shear stress because of hyperperfusion. Surgical manipulation and/or resection of the collapsed lung may induce lung injury. Re-expansion of the collapsed lung at the conclusion of OLV invariably induces duration-dependent, ischemia-reperfusion injury. Inflammatory cytokines are released in response to localized injury and may promote local and contralateral lung injury. Protective ventilation and volatile anesthesia lessen the degree of injury; however, increases in biochemical and histologic markers of lung injury appear unavoidable. The endothelial glycocalyx may represent a common pathway for lung injury creation during OLV, because it is damaged by most of the recognized lung injurious mechanisms. Experimental therapies to stabilize the endothelial glycocalyx may afford the ability to reduce lung injury in the future. In the interim, protective ventilation with tidal volumes of 4 to 5 mL/kg predicted body weight, positive end-expiratory pressure of 5 to 10 cm H2O, and routine lung recruitment should be used during OLV in an attempt to minimize harmful lung stress and strain. Additional strategies to reduce lung injury include routine volatile anesthesia and efforts to minimize OLV duration and hyperoxia.

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.

Acute kidney injury within 72 hours after lung transplantation: incidence and perioperative risk factors.

OBJECTIVE: To define the incidence and perioperative risk factors of acute kidney injury (AKI) within 72 hours after lung transplantation and clarify the relationship between postoperative AKI and outcome in patients undergoing lung transplantation. DESIGN: A retrospective observational study. SETTING: A tertiary care academic center. PARTICIPANTS: Fifty-four patients who underwent lung transplantation between January 2006 and March 2010. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: After excluding 4 patients who died or required additional surgery during the first 72 hours after transplantation, 50 patients were included in the final analysis. Data were extracted from medical charts and electronic health record information system. Risk, injury, failure, loss, endstage (RIFLE) renal disease creatinine criteria were used for the diagnosis of AKI. AKI developed in 27 patients (54%) within 72 hours after transplantation. The incidence of AKI after double-lung transplantation was 87% compared to 40% following single-lung transplantation. The percentage of patients with intraoperative hypoxemia (SpO2<90%) was significantly different between the groups (AKI, 59%; Non-AKI, 22%). Volume of hydroxyethyl starch was significantly higher in AKI patients (912±507 mL) than non-AKI patients (535±338 mL). Baseline estimated glomerular filtration rate (eGFR) was significantly higher in AKI patients (99±27 mL/min/1.73 m2) than non-AKI patients (77±20 mL/min/1.73 m2). CONCLUSIONS: AKI based on the RIFLE criteria following lung transplantation is common. Patients who developed AKI were more likely to have an episode of intraoperative hypoxemia and undergo a double-lung transplantation. Contrary to other published studies, patients with a higher preoperative eGFR were more likely to develop AKI in the authors' cohort.

Acute kidney injury after lung resection surgery: incidence and perioperative risk factors.

BACKGROUND: Postoperative acute kidney injury (AKI) is associated with increased perioperative morbidity and mortality in a variety of surgical settings, but has not been well studied after lung resection surgery. In the present study, we defined the incidence of postoperative AKI, identified risk factors, and clarified the relationship between postoperative AKI and outcome in patients undergoing lung resection surgery. METHODS: A retrospective, observational study of patients who underwent lung resection surgery between January 2006 and March 2010 in a tertiary care academic center was conducted. Postoperative AKI was diagnosed within 72 hours after surgery based on the Acute Kidney Injury Network creatinine criteria. Logistic regression was used to model the association between perioperative factors and the risk of AKI within 72 hours after surgery. The relationship between postoperative AKI and patient outcome including mortality, days in hospital, and the requirement of reintubation was investigated. RESULTS: A total of 1129 patients (pneumonectomy n = 71, bilobectomy n = 30, lobectomy n = 580, segmentectomy n = 35, wedge resection/bullectomy n = 413) were included in the final analysis. Patients were an average of 61 years (SD 15) and 50% were female. AKI was diagnosed in 67 patients (5.9%) based on Acute Kidney Injury Network criteria (stage 1, n = 59; stage 2, n = 8; and stage 3, n = 0) within 72 hours after surgery, and only 1 patient required renal replacement therapy. Multivariate analysis demonstrated an independent association between postoperative AKI and hypertension (adjusted odds ratio [OR] 2.0, 95% confidence interval [CI]: 1.1-3.8), peripheral vascular disease (OR 4.4, 95% CI: 1.8-10), estimated glomerular filtration rate (OR 0.8, 95% CI: 0.69-0.93), preoperative use of angiotensin II receptor blockers (OR 2.2, 95% CI: 1.1-4.4), intraoperative hydroxyethyl starch administration (OR 1.5, 95% CI: 1.1-2.1), and thoracoscopic (versus open) procedures (OR 0.37, 95% CI: 0.15-0.90). Development of AKI was associated with increased rates of tracheal reintubation (12% vs 2%, P < 0.001), postoperative mechanical ventilation (15% vs 3%, P < 0.001), and prolonged hospital length of stay (10 vs 8 days, P < 0.001). There was no difference in mortality between the 2 groups (3% vs 1%, P = 0.12). CONCLUSIONS: Preoperative risk factors for AKI after lung resection surgery overlap with those established for other surgical procedures. Perioperative management seems to influence the risk of AKI after lung resection; in particular, the use of synthetic colloids may increase the risk, whereas thoracoscopic procedures may decrease the risk of AKI. Early postoperative AKI is associated with respiratory complications and prolonged hospitalization.

Efficacy of ultrasound-guided single-injection erector spinae plane block for thoracoscopic wedge resection: a prospective randomized control trial.

BACKGROUND: Despite advances in minimally invasive thoracic surgery, patients remain at risk of adverse pulmonary events with suboptimal postoperative analgesia. Novel methods of regional analgesia are warranted. Our objective was to prospectively evaluate the impact of ultrasound-guided single-injection erector spinae plane (ESP) block with ropivacaine compared with placebo control on standard of care postoperative recovery in subjects undergoing video-assisted thoracoscopic surgery (VATS) wedge resection. METHODS: This prospective, randomized, placebo-controlled, double-blinded study was conducted at a tertiary thoracic surgical center. Consecutive subjects undergoing VATS wedge resection were randomized to receive a single-injection ESP block with 0.5% ropivacaine or 0.9% saline placebo, in addition to the current standard of care of multimodal analgesia including patient-controlled analgesia and surgical local anesthetic wound infiltration. The primary outcome was difference in 40-point Quality of Recovery (QoR-40) on day 1 postoperatively. The secondary outcomes included opioid consumption, Visual Analog Pain Scale (VAS) score, time spent in the postanesthesia care unit (PACU), and block-related and postoperative complications. RESULTS: Eighty subjects were enrolled, 40 in each group, with 76 completing follow-up (38 subjects in each group). There was no difference in the median QoR-40 score between groups, 169.5 for the ropivacaine group and 172.5 for the control group (difference 3, p=0.843). No significant differences existed between groups in all secondary outcomes, with the exception of the ropivacaine group having lower VAS pain scores measured at 1 hour postoperatively and a shorter duration of stay in the PACU of 117 min. CONCLUSIONS: Following VATS wedge resection, the addition of an ESP block with ropivacaine to standard multimodal analgesia is unlikely to add meaningful clinical value. TRIAL REGISTRATION NUMBER: NCT03419117.

Utility of prepuncture ultrasound for localization of the thoracic epidural space.

BACKGROUND: Ultrasound has been shown to facilitate accurate identification of the intervertebral level and to predict skin-to-epidural depth in the lumbar epidural space with reliable precision. We hypothesized that we could accurately predict the skin-to-epidural depth and the intervertebral level in the thoracic spine with the use of ultrasound. METHODS: Twenty patients presenting for thoracic surgery were included in a feasibility study. The skin-to-epidural depth was measured using prepuncture ultrasound in the paramedian window, and the predicted depth was compared with the actual needle depth and the depth as measured by computed tomography. In addition, the intervertebral levels were identified by ultrasound using the "counting up" method, and the results were compared with the levels identified by anesthesiologists. RESULTS: The ultrasound-based depth measurements displayed a bias of 3.21 mm with 95% limits of agreement from -7.47 to 13.9 mm compared with the clinically determined needle depth. The intervertebral levels identified by the anesthesiologists and the sonographer matched in only 40% of cases. CONCLUSION: Ultrasound-based measurements of skin-to-epidural depth show acceptable agreement with the actual depth observed during epidural catheterization; however, the limits of agreement are wide, which restricts the predictive value of ultrasound-based measurements. Further study is required to delineate the role of ultrasound in thoracic epidural catheterizations.

One-lung ventilation and arterial oxygenation.

PURPOSE OF REVIEW: Hypoxemia during one-lung ventilation (OLV) has become less common; however, it may still occur in about 10% of cases. We review recent developments which may affect the incidence and treatment of hypoxemia during OLV. RECENT FINDINGS: Changes in surgical techniques are affecting oxygenation during OLV. The increased use of the supine position may adversely affect the prevalence of hypoxemia, whereas the increased application of thoracoscopic techniques is limiting the treatment options. Treatment options such as global or selective recruitment maneuvers and drug effects of dexmedetomidine and epoprostenol on arterial oxygenation during OLV are discussed. Capnometry prior to, or early during OLV, may in fact be able to predict the degree of hypoxemia during OLV. Persistent controversies surrounding the effect of epidural anesthesia, ventilatory modalities and gravity are reviewed. SUMMARY: Interesting concepts have emerged from case reports and small studies on the treatment and prediction of hypoxemia during OLV. Definitive studies on the most effective ventilatory mode remain elusive. End-organ effects of OLV are an exciting new concept that may shape clinical practice and research going forward.

Hypoxemia During One-Lung Ventilation: Does It Really Matter?

PURPOSE OF REVIEW: Hypoxemia during one-lung ventilation, while decreasing in frequency, persists as an intraoperative challenge for anesthesiologists. Discerning when desaturation and resultant hypoxemia correlates to tissue hypoxia is challenging in the perioperative setting and requires a thorough understanding of the physiology of oxygen delivery and tissue utilization. RECENT FINDINGS: Oxygen delivery is not directly correlated with peripheral oxygen saturation in patients undergoing one-lung ventilation, emphasizing the importance of hemoglobin concentration and cardiac output in avoiding tissue hypoxia. While healthy humans can tolerate acute hypoxemia without long-term consequences, there is a paucity of evidence from patients undergoing thoracic surgery. Increasingly recognized is the potential harm of hyperoxic states, particularly in the setting of complex patients with comorbid diseases. SUMMARY: Anesthesiologists are left to determine an acceptable oxygen saturation nadir that is individualized to the patient and procedure based on an understanding of oxygen supply, demand, and the consequences of interventions.

Thoracoscopic wedge resection of the lung using high-frequency jet ventilation in a postpneumonectomy patient.

A 61-year-old female ex-smoker presented with a suspicious right lower lobe mass after previously undergoing a left pneumonectomy. Due to the peripheral nature of the lung lesion, a right thoracoscopic wedge resection was proposed by the surgical team. Adequate ventilation, oxygenation, and surgical conditions were obtained using high-frequency jet ventilation to the operative lung throughout the procedure. The trachea was extubated in the operating room, and the patient recovered uneventfully from the procedure. This case demonstrates the feasibility of limited thoracoscopic lung resections postpneumonectomy with the use of high-frequency jet ventilation.