Andrea Vannucci

Long-term cognitive decline in older subjects was not attributable to noncardiac surgery or major illness.

Background:Persistent postoperative cognitive decline is thought to be a public health problem, but its severity may have been overestimated because of limitations in statistical methodology. This study assessed whether long-term cognitive decline occurred after surgery or illness by using an innovative approach and including participants with early Alzheimer disease to overcome some limitations. Methods:In this retrospective cohort study, three groups were identified from participants tested annually at the Washington University Alzheimers Disease Research Center in St. Louis, Missouri: those with noncardiac surgery, illness, or neither. This enabled long-term tracking of cognitive function before and after surgery and illness. The effect of surgery and illness on longitudinal cognitive course was analyzed using a general linear mixed effects model. For participants without initial dementia, time to dementia onset was analyzed using sequential Cox proportional hazards regression. Results:Of the 575 participants, 214 were nondemented and 361 had very mild or mild dementia at enrollment. Cognitive trajectories did not differ among the three groups (surgery, illness, control), although demented participants declined more markedly than nondemented participants. Of the initially nondemented participants, 23% progressed to a clinical dementia rating greater than zero, but this was not more common after surgery or illness. Conclusions:The study did not detect long-term cognitive decline independently attributable to surgery or illness, nor were these events associated with accelerated progression to dementia. The decision to proceed with surgery in elderly people, including those with early Alzheimer disease, may be made without factoring in the specter of persistent cognitive deterioration.

Review article: Extubation of the difficult airway and extubation failure.

Respiratory complications after tracheal extubation are associated with significant morbidity and mortality, suggesting that process improvements in this clinical area are needed. The decreased rate of respiratory adverse events occurring during tracheal intubation since the implementation of guidelines for difficult airway management supports the value of education and guidelines in advancing clinical practice. Accurate use of terms in defining concepts and describing distinct clinical conditions is paramount to facilitating understanding and fostering education in the treatment of tracheal extubation-related complications. As an example, understanding the distinction between extubation failure and weaning failure allows one to appreciate the need for pre-extubation tests that focus on assessing airway patency in addition to evaluating the ability to breathe spontaneously. Tracheal reintubation after planned extubation is a relatively rare event in the postoperative period of elective surgeries, with reported rates of reintubation in the operating room and postanesthesia care unit between 0.1% and 0.45%, but is a fairly common event in critically ill patients (0.4%–25%). Conditions such as obesity, obstructive sleep apnea, major head/neck and upper airway surgery, and obstetric and cervical spine procedures carry significantly increased risks of extubation failure and are frequently associated with difficult airway management. Extubation failure follows loss of upper airway patency. Edema, soft tissue collapse, and laryngospasm are among the most frequent mechanisms of upper airway obstruction. Planning for tracheal extubation is a critical component of a successful airway management strategy, particularly when dealing with situations at increased risk for extubation failure and in patients with difficult airways. Adequate planning requires identification of patients who have or may develop a difficult airway, recognition of situations at increased risk of postextubation airway compromise, and understanding the causes and underlying mechanisms of extubation failure. An effective strategy to minimize postextubation airway complications should include preemptive optimization of patients’ conditions, careful timing of extubation, the presence of experienced personnel trained in advanced airway management, and the availability of the necessary equipment and appropriate postextubation monitoring.

Comparison of calibrated and uncalibrated arterial pressure-based cardiac output monitors during orthotopic liver transplantation.

Arterial pressure–based cardiac output monitors (APCOs) are increasingly used as alternatives to thermodilution. Validation of these evolving technologies in high‐risk surgery is still ongoing. In liver transplantation, FloTrac‐Vigileo (Edwards Lifesciences) has limited correlation with thermodilution, whereas LiDCO Plus (LiDCO Ltd.) has not been tested intraoperatively. Our goal was to directly compare the 2 proprietary APCO algorithms as alternatives to pulmonary artery catheter thermodilution in orthotopic liver transplantation (OLT). The cardiac index (CI) was measured simultaneously in 20 OLT patients at prospectively defined surgical landmarks with the LiDCO Plus monitor (CIL) and the FloTrac‐Vigileo monitor (CIV). LiDCO Plus was calibrated according to the manufacturers instructions. FloTrac‐Vigileo did not require calibration. The reference CI was derived from pulmonary artery catheter intermittent thermodilution (CITD). CIV‐CITD bias ranged from −1.38 (95% confidence interval = −2.02 to −0.75 L/minute/m2, P = 0.02) to −2.51 L/minute/m2 (95% confidence interval = −3.36 to −1.65 L/minute/m2, P < 0.001), and CIL‐CITD bias ranged from −0.65 (95% confidence interval = −1.29 to −0.01 L/minute/m2, P = 0.047) to −1.48 L/minute/m2 (95% confidence interval = −2.37 to −0.60 L/minute/m2, P < 0.01). For both APCOs, bias to CITD was correlated with the systemic vascular resistance index, with a stronger dependence for FloTrac‐Vigileo. The capability of the APCOs for tracking changes in CITD was assessed with a 4‐quadrant plot for directional changes and with receiver operating characteristic curves for specificity and sensitivity. The performance of both APCOs was poor in detecting increases and fair in detecting decreases in CITD. In conclusion, the calibrated and uncalibrated APCOs perform differently during OLT. Although the calibrated APCO is less influenced by changes in the systemic vascular resistance, neither device can be used interchangeably with thermodilution to monitor cardiac output during liver transplantation. Liver Transpl 16:773‐782, 2010.

Retained guidewires after intraoperative placement of central venous catheters

Guidewire retention is a rare complication of central venous catheter placement, and has been related to operator fatigue, inexperience, and inattention, and inadequate supervision of trainees. The true incidence of guidewire loss after intraoperative placement of central venous catheters is unknown. We report 4 cases of guidewire loss after central venous access procedures performed by anesthesia providers in the operating room. Worsening of patients’ clinical condition during catheter placement and complex procedures necessitating more than one guidewire insertion are recurring scenarios in cases involving guidewire loss. Over 6 years at our institution, intraoperative wire loss occurred at a rate of 1:3291 procedures (95% confidence interval of 1/10,000 to 8/10,000).

Preoperative use of incentive spirometry does not affect postoperative lung function in bariatric surgery

Morbidly obese patients undergoing general anesthesia for laparoscopic bariatric surgery are considered at increased risk of a postoperative decrease in lung function. The purpose of this study was to determine whether a systematic use of incentive spirometry (IS) prior to surgery could help patients to preserve their respiratory function better in the postoperative period. Forty-one morbidly obese (body mass index [BMI] > 40 kg/m²) candidates for laparoscopic bariatric surgery were consented in the study. All patients were taught how to use an incentive spirometer but then were randomized blindly into 2 groups. The control group was instructed to use the incentive spirometer for 3 breaths, once per day. The treatment group was requested to use the incentive spirometer for 10 breaths, 5 times per day. Twenty experimental (mean BMI of 48.9 ± 5.67 kg/m²) and 21 control patients (mean BMI of 48.3 ± 6.96 kg/m²) were studied. The initial mean inspiratory capacity (IC) was 2155 ± 650.08 (SD) cc and 2171 ± 762.98 cc in the experimental and control groups, respectively. On the day of surgery, the mean IC was 2275 ± 777.56 cc versus 2254.76 ± 808.84 cc, respectively. On postoperative day 1, both groups experienced a significant drop of their IC, with volumes of 1458 ± 613.87 cc (t test P < 0.001) and 1557.89 ± 814.67 cc (t test P < 0.010), respectively. Our results suggest that preoperative use of the IS does not lead to significant improvements of inspiratory capacity and that it is a not a useful resource to prevent postoperative decrease in lung function.

Extubation of the Difficult Airway and Extubation Failure

2012, support the recommendation that an EEG-based monitor should be considered for patients receiving total intravenous anesthesia. Furthermore, the NICE guidelines recommend that such EEG-based monitors should be considered for patients who may be at higher risk for AWR, who are likely to experience hemodynamic instability at usual anesthetic doses, or for whom there is a theoretical concern, owing to their perceived fragility or vulnerability, that typical anesthetic doses could be harmful. Clearly, this is an area where we have more questions than answers. It is encouraging, however, that this issue is now receiving serious attention. One hopes that our patients will benefit.

Atrial Fibrillation in Patients Undergoing Liver Transplantation—A Single-Center Experience

BACKGROUND As the prevalence of atrial fibrillation rises with age and older patients increasingly receive transplants, the perioperative management of this common arrhythmia and its impact on outcomes in liver transplantation is of relevance. METHODS Retrospective review of 757 recipients of liver transplantation from January 2002 through December 2011. RESULTS Nineteen recipients (2.5%) had documented pre-transplantation atrial fibrillation. Sixteen patients underwent liver and 3 a combined liver-kidney transplantation. Three patients died within 30 days (84.2% 1-month survival) and another 3 within 1 year of transplantation (68.4% 1-year survival). Compared with patients without atrial fibrillation, the relative risk of death in the atrial fibrillation group was 5.29 at 1 month (P = .0034; 95% confidence interval [CI], 1.73-16.18) and 3.28 at 1 year (P = .0008; 95% CI, 1.63-6.59). Time to extubation and intensive care unit (ICU) and hospital readmissions were not different from the control cohort. Rapid ventricular response requiring treatment occurred in 4 patients during surgery and 7 after surgery, resulting in 3 ICU and 3 hospital readmissions. CONCLUSIONS The results suggest that patients with atrial fibrillation may be at increased risk of mortality after liver transplantation. Optimization of medical therapy may decrease ICU and hospital readmission due to rapid ventricular response.

Creating and evaluating a data-driven curriculum for central venous catheter placement.

BACKGROUND Central venous catheter placement is a common procedure with a high incidence of error. Other fields requiring high reliability have used Failure Mode and Effects Analysis (FMEA) to prioritize quality and safety improvement efforts. OBJECTIVE To use FMEA in the development of a formal, standardized curriculum for central venous catheter training. METHODS We surveyed interns regarding their prior experience with central venous catheter placement. A multidisciplinary team used FMEA to identify high-priority failure modes and to develop online and hands-on training modules to decrease the frequency, diminish the severity, and improve the early detection of these failure modes. We required new interns to complete the modules and tracked their progress using multiple assessments. RESULTS Survey results showed new interns had little prior experience with central venous catheter placement. Using FMEA, we created a curriculum that focused on planning and execution skills and identified 3 priority topics: (1) retained guidewires, which led to training on handling catheters and guidewires; (2) improved needle access, which prompted the development of an ultrasound training module; and (3) catheter-associated bloodstream infections, which were addressed through training on maximum sterile barriers. Each module included assessments that measured progress toward recognition and avoidance of common failure modes. Since introducing this curriculum, the number of retained guidewires has fallen more than 4-fold. Rates of catheter-associated infections have not yet declined, and it will take time before ultrasound training will have a measurable effect. CONCLUSION The FMEA provided a process for curriculum development. Precise definitions of failure modes for retained guidewires facilitated development of a curriculum that contributed to a dramatic decrease in the frequency of this complication. Although infections and access complications have not yet declined, failure mode identification, curriculum development, and monitored implementation show substantial promise for improving patient safety during placement of central venous catheters.

A Near Miss: A Nitrous Oxide-Carbon Dioxide Mix-up Despite Current Safety Standards

fidelity models may have an advantage later in the learning curve supporting a graduated approach through models of increasing fidelity. However, we would like to suggest an alternative factor that affects the analysis of Chandra’s findings. In addition to differences in fidelity, the models used can also be differentiated according to the part task training theory. Part task training is defined as the deconstruction of multicomponent tasks into several single-component tasks. When each skill is learned separately, the single-task format allows a more rapid development of automaticity, reducing processing demands during subsequent integration into the performance of the whole procedure. Fiberoptic orotracheal intubation is a complex psychomotor task which requires the association of two component skills: The manipulation of the fiberoptic bronchoscope and the appreciation of the endoscopic view of the upper airway anatomy. The AccuTouch Flexible Bronchoscopy Simulator (Immersion Medical, Gaithersburg, MD) can be considered a full task trainer model, whereas the “choose-the-hole” model can be classified as a single task trainer dedicated to learn specifically the manipulation of the bronchoscope. The other component skill of identifying the endoscopic appearance of the airway anatomy can be achieved through other simulators such as the virtual fiberoptic intubation part task trainer. The virtual fiberoptic intubation software (Institut de Recherche contre les Cancers de l’Appareil Digestif, Strasbourg, France) is a free screenbased simulator that focuses on learning normal and altered endoscopic airway anatomy away from the fiberoptic bronchoscope. Using only the computer’s mouse or keyboard, this virtual progression helps the learner to mentally integrate the schema of the correct airway route. The difference between the groups in Chandra’s study is not only one of fidelity, but also the difference between a full-task and a part-task simulation. It is interesting that there was no difference between the groups, and we can only speculate whether there would have been a difference if the part-task group had in addition used another part-task trainer such as the virtual fiberoptic intubation part task trainer to enable deliberate practice of both component skills. We suspect that each type of simulator has a specific role. Part task trainers may be used for learning each component of a complex task, whereas full task trainers may be used to integrate those skills before working in the clinical setting. Given that Chandra et al. found a single part task trainer to be equivalent to a full task trainer, we hypothesize that the use of complementary single task trainers has the potential to be more effective than a full task trainer in early skill acquisition for fiberoptic orotracheal intubation.

Postreperfusion cardiac arrest and resuscitation during orthotopic liver transplantation: dynamic visualization and analysis of physiologic recordings.

ABSTRACT We recently reported on the Multi Wave Animator (MWA), a novel open-source tool with capability of recreating continuous physiologic signals from archived numerical data and presenting them as they appeared on the patient monitor. In this report, we demonstrate for the first time the power of this technology in a real clinical case, an intraoperative cardiopulmonary arrest following reperfusion of a liver transplant graft. Using the MWA, we animated hemodynamic and ventilator data acquired before, during, and after cardiac arrest and resuscitation. This report is accompanied by an online video that shows the most critical phases of the cardiac arrest and resuscitation and provides a basis for analysis and discussion. This video is extracted from a 33-min, uninterrupted video of cardiac arrest and resuscitation, which is available online. The unique strength of MWA, its capability to accurately present discrete and continuous data in a format familiar to clinicians, allowed us this rare glimpse into events leading to an intraoperative cardiac arrest. Because of the ability to recreate and replay clinical events, this tool should be of great interest to medical educators, researchers, and clinicians involved in quality assurance and patient safety.