Michael C. Sklar

Mechanical Ventilation–induced Diaphragm Atrophy Strongly Impacts Clinical Outcomes

Rationale: Diaphragm dysfunction worsens outcomes in mechanically ventilated patients, but the clinical impact of potentially preventable changes in diaphragm structure and function caused by mechanical ventilation is unknown. Objectives: To determine whether diaphragm atrophy developing during mechanical ventilation leads to prolonged ventilation. Methods: Diaphragm thickness was measured daily by ultrasound in adults requiring invasive mechanical ventilation; inspiratory effort was assessed by thickening fraction. The primary outcome was time to liberation from ventilation. Secondary outcomes included complications (reintubation, tracheostomy, prolonged ventilation, or death). Associations were adjusted for age, severity of illness, sepsis, sedation, neuromuscular blockade, and comorbidity. Measurements and Main Results: Of 211 patients enrolled, 191 had two or more diaphragm thickness measurements. Thickness decreased more than 10% in 78 patients (41%) by median Day 4 (interquartile range, 3‐5). Development of decreased thickness was associated with a lower daily probability of liberation from ventilation (adjusted hazard ratio, 0.69; 95% confidence interval [CI], 0.54‐0.87; per 10% decrease), prolonged ICU admission (adjusted duration ratio, 1.71; 95% CI, 1.29‐2.27), and a higher risk of complications (adjusted odds ratio, 3.00; 95% CI, 1.34‐6.72). Development of increased thickness (n = 47; 24%) also predicted prolonged ventilation (adjusted duration ratio, 1.38; 95% CI, 1.00‐1.90). Decreasing thickness was related to abnormally low inspiratory effort; increasing thickness was related to excessive effort. Patients with thickening fraction between 15% and 30% (similar to breathing at rest) during the first 3 days had the shortest duration of ventilation. Conclusions: Diaphragm atrophy developing during mechanical ventilation strongly impacts clinical outcomes. Targeting an inspiratory effort level similar to that of healthy subjects at rest might accelerate liberation from ventilation.

Effort To Breathe With Various Spontaneous Breathing Trial Techniques. A Physiological Meta-analysis

Rationale: Spontaneous breathing trials (SBTs) are designed to simulate conditions after extubation, and it is essential to understand the physiologic impact of different methods. Objectives: We conducted a systematic review and pooled measures reflecting patient respiratory effort among studies comparing SBT methods in a meta‐analysis. Methods: We searched Medline, Excerpta Medica Database, and Web of Science from inception to January 2016 to identify randomized and nonrandomized clinical trials reporting physiologic measurements of respiratory effort (pressure‐time product) or work of breathing during at least two SBT techniques. Secondary outcomes included the rapid shallow breathing index (RSBI), and effort measured before and after extubation. The quality of physiologic measurement and research design was appraised for each study. Outcomes were analyzed using ratio of means. Measurements and Main Results: Among 4,138 citations, 16 studies (n = 239) were included. Compared with T‐piece, pressure support ventilation significantly reduced work by 30% (ratio of means [RoM], 0.70; 95% confidence interval [CI], 0.57‐0.86), effort by 30% (RoM, 0.70; 95% CI, 0.60‐0.82), and RSBI by 20% (RoM, 0.80; 95% CI, 0.75‐0.86). Continuous positive airway pressure had significantly lower pressure‐time product by 18% (RoM, 0.82; 95% CI, 0.68‐0.999) compared with T‐piece, and reduced RSBI by 16% (RoM, 0.84; 95% CI, 0.74‐0.95). Studies comparing SBTs with the postextubation period demonstrated that pressure support induced significantly lower effort and RSBI; T‐piece reduced effort, but not the work, compared with postextubation. Work, effort, and RSBI measured while intubated on the ventilator with continuous positive airway pressure of 0 cm H2O were no different than extubation. Conclusions: Pressure support reduces respiratory effort compared with T‐piece. Continuous positive airway pressure of 0 cm H2O and T‐piece more accurately reflect the physiologic conditions after extubation.

Endoscopic Resection of Solitary Fibrous Tumors of the Nose and Paranasal Sinuses

Solitary fibrous tumors (SFTs) are uncommon neoplasms of mesenchymal origin that were first described as primary spindle-cell tumors of the pleura in 1931. Since then, infrequent case reports of extrapleural SFTs have been described including various subsites within the head and neck. Based on a review of the literature and a description of the endoscopic treatment of three patients with SFTs of the nasal cavity and ethmoid sinuses, the challenges associated with the management of sinonasal SFTs are discussed. Successful endoscopic resection was performed at a tertiary referral rhinology practice within a university center in three cases of sinonasal SFTs with no evidence of recurrence at 26, 35, and 49 months following resection. Summarized are the common presenting symptoms, appropriate diagnostic workup, and indicative computed tomography and magnetic resonance imaging appearance of SFTs. Further discussed are the challenge associated with accurate histological and immunohistochemical diagnosis, the difficulty in assessing the aggressiveness and malignant potential of these lesions, and the appropriate treatment and follow-up duration that these neoplasms require.

Anticoagulation practices and the prevalence of major bleeding, thromboembolic events, and mortality in venoarterial extracorporeal membrane oxygenation: A systematic review and meta-analysis

Purpose: The purpose was to evaluate the safety of anticoagulation in venoarterial extracorporeal membrane oxygenation (VA‐ECMO). Design: We performed a systematic review and meta‐analysis using multiple electronic databases. Studies were from 1977 to September 27, 2016. We evaluated the effect of anticoagulation in VA‐ECMO on outcomes including major bleeding, thromboembolic events, and in‐hospital mortality using a random effects model meta‐analysis. Results: Twenty‐six studies (1496 patients) were included. Ten studies only had patients with postcardiotomy shock, 4 studies only included extracorporeal cardiopulmonary resuscitation patients, and 10 studies had a mixture of patients. Most studies (n = 17) were low quality with a Newcastle‐Ottawa Scale score ≤5. The summary prevalence of major bleeding was 27% (95% confidence interval [CI], 18%‐35%), with considerable between‐study heterogeneity (I2 = 91%). Major bleeding requiring reoperation was the most common bleeding event. The summary prevalence of thromboembolic events was 8% (95% CI, 4%‐13%; I2 = 83%). Limb ischemia, circuit‐related clotting, and stroke were the most commonly reported events. The summary prevalence for in‐hospital mortality was 59% (95% CI, 52%‐67%; I2 = 78%). Conclusions: The optimal targets and strategies for anticoagulation in VA‐ECMO are unclear. Evaluation of major bleeding and thromboembolic events is limited by study quality and between‐study heterogeneity. Clinical trials are needed to investigate the optimal anticoagulation strategy. HighlightsThe optimal strategy for anticoagulation is currently unknown for patients on venoarterial extracorporeal membrane oxygenation.We performed a systematic review and meta‐analysisMajor bleeding events were very common in all studies with a summary prevalence of 27%.Significant between‐study heterogeneity limits any recommendations for the optimal strategy of anticoagulationFurther clinical trials are needed to examine this question.

Radiographic features in a rare case of sphenoid sinus extramedullary hematopoeisis in sickle cell disease.

Sickle cell disease is a common hematologic disorder with some uncommon clinical manifestations. While there are an abundance of described disease manifestations of the head and neck, extramedullary hematopoesis within the paranasal sinuses is exceedingly rare. Here, we present a case of a young boy with known sickle cell disease who presented to hospital with headaches of new onset. Imaging demonstrated an expansile mass lesion occupying the sphenoid sinus and on biopsy was found to be active hematopoetic bone marrow. A description of the case and review of subtle but characteristic radiographic findings follow.

Trials directly comparing alternative spontaneous breathing trial techniques: a systematic review and meta-analysis

BackgroundThe effect of alternative spontaneous breathing trial (SBT) techniques on extubation success and other clinically important outcomes is uncertain.MethodsWe searched MEDLINE, EMBASE, CENTRAL, CINAHL, Evidence-Based Medicine Reviews, Ovid Health Star, proceedings of five conferences (1990–2016), and reference lists for randomized trials comparing SBT techniques in intubated adults or children. Primary outcomes were initial SBT success, extubation success, or reintubation. Two reviewers independently screened citations, assessed trial quality, and abstracted data.ResultsWe identified 31 trials (n = 3541 patients). Moderate-quality evidence showed that patients undergoing pressure support (PS) compared with T-piece SBTs (nine trials, n = 1901) were as likely to pass an initial SBT (risk ratio (RR) 1.00, 95% confidence interval (CI) 0.89–1.11; I2 = 77%) but more likely to be ultimately extubated successfully (RR 1.06, 95% CI 1.02–1.10; 11 trials, n = 1904; I2 = 0%). Exclusion of one trial with inconsistent results for SBT and extubation outcomes suggested that PS (vs T-piece) SBTs also improved initial SBT success (RR 1.06, 95% CI 1.01–1.12; I2 = 0%). Limited data suggest that automatic tube compensation plus continuous positive airway pressure (CPAP) vs CPAP alone or PS increase SBT but not extubation success.ConclusionsPatients undergoing PS (vs T-piece) SBTs appear to be 6% (95% CI 2–10%) more likely to be extubated successfully and, if the results of an outlier trial are excluded, 6% (95% CI 1–12%) more likely to pass an SBT. Future trials should investigate patients for whom SBT and extubation outcomes are uncertain and compare techniques that maximize differences in support.

Angiogenesis in costal cartilage graft laryngotracheoplasty: a corrosion casting study in piglets.

To investigate the timing and degree of angiogenesis following anterior costal cartilage graft laryngotracheoplasty in an animal model.

Corrosion casting of the subglottis following endotracheal tube intubation injury: a pilot study in Yorkshire piglets

PurposeSubglottic stenosis can result from endotracheal tube injury. The mechanism by which this occurs, however, is not well understood. The purpose of this study was to examine the role of angiogenesis, hypoxia and ischemia in subglottic mucosal injury following endotracheal intubation.MethodsSix Yorkshire piglets were randomized to either a control group (N=3, ventilated through laryngeal mask airway for corrosion casting) or accelerated subglottic injury group through intubation and induced hypoxia as per a previously described model (N=3). The vasculature of all animals was injected with liquid methyl methacrylate. After polymerization, the surrounding tissue was corroded with potassium hydroxide. The subglottic region was evaluated using scanning electron microscopy looking for angiogenic and hypoxic or degenerative features and groups were compared using Mann–Whitney tests and Friedman’s 2-way ANOVA.ResultsAnimals in the accelerated subglottic injury group had less overall angiogenic features (P=.002) and more overall hypoxic/degenerative features (P=.000) compared with controls. Amongst angiogenic features, there was decreased budding (P=.000) and a trend toward decreased sprouting (P=.037) in the accelerated subglottic injury group with an increase in intussusception (P=.004), possibly representing early attempts at rapid revascularization. Amongst hypoxic/degenerative features, extravasation was the only feature that was significantly higher in the accelerated subglottic injury group (P=.000).ConclusionsSubglottic injury due to intubation and hypoxia may lead to decreased angiogenesis and increased blood vessel damage resulting in extravasation of fluid and a decreased propensity toward wound healing in this animal model.

High-Frequency Oscillatory Ventilation in Adults With ARDS: Past, Present, and Future

&NA; High‐frequency oscillatory ventilation (HFOV) is a unique mode of mechanical ventilation that uses nonconventional gas exchange mechanisms to deliver ventilation at very low tidal volumes and high frequencies. The properties of HFOV make it a potentially ideal mode to prevent ventilator‐induced lung injury in patients with ARDS. Despite a compelling physiological basis and promising experimental data, large randomized controlled trials have not detected an improvement in survival with the use of HFOV, and its use as an early lung‐protective strategy in patients with ARDS may be harmful. Nevertheless, HFOV still has an important potential role in the management of refractory hypoxemia. Careful attention should be paid to right ventricular function and lung stress when applying HFOV. This review discusses the physiological principles, clinical evidence, practical applications, and future prospects for the use of HFOV in patients with ARDS.

A solitary tonsil can cause severe obstructive sleep apnea

Hypertrophy of the tonsils and adenoids is the most common cause of pediatric obstructive sleep apnea. Bilateral tonsillectomy, most commonly performed with adenoidectomy, is the accepted treatment for obstructive sleep apnea. We report the unusual case of a child who underwent unilateral tonsillectomy and adenoidectomy at another institution and subsequently presented to us with persistent severe obstructive sleep apnea and a diagnosis of attention deficit hyperactivity disorder. The adenoids were not obstructing the choanae. The remaining tonsil was removed and the patients sleep apnea resolved. This is the first objectively documented report of a solitary tonsil causing severe obstructive sleep apnea (using polysomnography) that resolved after removal of the remaining tonsil.