Computational simulation to assess patient safety of uncompensated COVID-19 two-patient ventilator sharing using the Pulse Physiology Engine.

BACKGROUND: The COVID-19 pandemic is stretching medical resources internationally, sometimes creating ventilator shortages that complicate clinical and ethical situations. The possibility of needing to ventilate multiple patients with a single ventilator raises patient health and safety concerns in addition to clinical conditions needing treatment. Wherever ventilators are employed, additional tubing and splitting adaptors may be available. Adjustable flow-compensating resistance for differences in lung compliance on individual limbs may not be readily implementable. By exploring a number and range of possible contributing factors using computational simulation without risk of patient harm, this paper attempts to define useful bounds for ventilation parameters when compensatory resistance in limbs of a shared breathing circuit is not possible. This desperate approach to shared ventilation support would be a last resort when alternatives have been exhausted. METHODS: A whole-body computational physiology model (using lumped parameters) was used to simulate each patient being ventilated. The primary model of a single patient with a dedicated ventilator was augmented to model two patients sharing a single ventilator. In addition to lung mechanics or estimation of CO2 and pH expected for set ventilation parameters (considerations of lung physiology alone), full physiological simulation provides estimates of additional values for oxyhemoglobin saturation, arterial oxygen tension, and other patient parameters. A range of ventilator settings and patient characteristics were simulated for paired patients. FINDINGS: To be useful for clinicians, attention has been directed to clinically available parameters. These simulations show patient outcome during multi-patient ventilation is most closely correlated to lung compliance, oxygenation index, oxygen saturation index, and end-tidal carbon dioxide of individual patients. The simulated patient outcome metrics were satisfactory when the lung compliance difference between two patients was less than 12 mL/cmH2O, and the oxygen saturation index difference was less than 2 mmHg. INTERPRETATION: In resource-limited regions of the world, the COVID-19 pandemic will result in equipment shortages. While single-patient ventilation is preferable, if that option is unavailable and ventilator sharing using limbs without flow resistance compensation is the only available alternative, these simulations provide a conceptual framework and guidelines for clinical patient selection.

Pulmonary pyoderma gangrenosum without cutaneous manifestations.

Pyoderma gangrenosum is a chronic sterile skin disorder that is frequently seen in association with systemic disorders such as inflammatory bowel disease. Extracutaneous pyoderma gangrenosum is rare and most commonly occurs in the lungs. It is particularly unusual for extracutaneous pyoderma gangrenosum to manifest prior to skin findings and without an associated systemic disorder. A 19-year-old white man presented with shortness of breath and a productive cough. His skin exam was normal. Unenhanced chest computed tomography showed peripheral consolidations, areas of cavitation, nodules and bilateral pleural effusions. A bronchoalveolar lavage and an autoimmune panel were unremarkable. Right lung wedge biopsies via thoracostomy was performed and showed pulmonary pyoderma gangrenosum. He was treated with corticosteroids and has returned back to his baseline. This is the first case of pulmonary pyoderma gangrenosum without any associated underlying systemic disorder and without any cutaneous manifestations to date. Serial follow-ups are necessary to assess for the development of an associated systemic disorder or skin lesions.

Efficacy of percutaneous pigtail catheters for thoracostomy at bedside.

OBJECTIVE: Given the potential morbidity of traditional chest tube insertion, use of pigtail is desirable. The purpose of this case series is to determine the efficacy of bedside pigtail thoracostomy catheters in Adult population by using bedside ultrasound by the pulmonologists. METHODS: It is a retrospective case series, which describes the importance of bedside pigtail catheters placements for emergent symptomatic relief for the patients. Predicting a successful drainage, procedure is a complex and multifactorial process based on size, location, character and configuration of the abscess. RESULTS: Our experience shows that the use of standard size (7-8.5 F) pigtail catheters is usually very successful in draining of the pleural fluids. Less time consumption, lower cost and bedside technique makes it superior to conventional chest tube placement in many aspects. CONCLUSIONS: Percutaneous pigtail catheters are useful in the drainage of pleural fluids. The pigtail catheters can be placed successful at bedside by the pulmonologists under ultrasound guidance with minimal complications and marked clinical improvement. The cost effectives of this procedure over the conventional chest tube placement, makes this procedure more desirable in most of the hospital settings.

Peripartum acute aortic dissection: A case report & review of literature.

Acute aortic dissection is a rare clinical entity that mainly affects patients older than 50 years. It is unusual in younger patients and its presence has been traditionally associated with trauma, Marfan syndrome, bicuspid aortic valve and pregnancy. We present here, a case of a 30 year old pregnant female with acute aortic dissection type A (De Bakey II), without family history of connective tissue diseases and signs of Marfan syndrome.

Intracranial hemorrhage in infective endocarditis: A case report.

Cerebral hemorrhage occurs rarely in infective endocarditis. Here, we present an interesting case of infective endocarditis complicated by sever cerebral hemorrhage. Later, his blood culture grew S bovis. To the best of our knowledge, this is the first ever reported case of S Bovis infective endocarditis complicated by extensive intracranial hemorrhage.

Lung transplant in end-staged chronic obstructive pulmonary disease (COPD) patients: a concise review.

Lung transplantation is commonly used for patients with end-stage lung disease. However, there is continuing debate on the optimal operation for patients with chronic obstructive pulmonary disease (COPD) and pulmonary fibrosis. Single-lung transplantation (SLT) provides equivalent short- and medium-term results compared with bilateral lung transplantation (BLT), but long-term survival appears slightly better in BLT recipients (especially in patients with COPD). The number of available organs for lung transplantation also influences the choice of operation. Recent developments suggest that the organ donor shortage is not as severe as previously thought, making BLT a possible alternative for more patients. Among the different complications, re-implantation edema, infection, rejection, and bronchial complications predominate. Chronic rejection, also called obliterative bronchiolitis syndrome, is a later complication which can be observed in about half of the patients. Improvement in graft survival depends greatly in improvement in prevention and management of complications. Despite such complications, graft survival in fibrosis patients is greater than spontaneous survival on the waiting list; idiopathic fibrosis is associated with the highest mortality on the waiting list. Patients should be referred early for the pre-transplantation work-up because individual prognosis is very difficult to predict.

Myocardial Infarction (MI) presenting as acute limb: an extremely rare presentation of MI.

Acute embolic occlusion of the bilateral lower limbs from the left ventricular thrombus is an extremely rare medical condition that is not only limb threatening but also potentially life threatening. Several strategies are available but not even a single treatment modality is clearly the best. Here, we present an interesting case that presented with bilateral lower limb ischemia and was later found to have a big thrombus in the left ventricle as the source of the emboli.

Surgical treatment of active infective endocarditis: A single center experience.

OBJECTIVE: This study was undertaken to examine the outcomes of surgery for active infective endocarditis. METHODS: Fifty consecutive patients underwent surgery for active infective endocarditis in a tertiary care center between January 2000 and June 2003. Modified Duke Criteria was used to include the patients in the study. RESULTS: Mean age of the patients was 55.72 years (range 18-89 years). Underlying heart disease was the most common cause of acute infection, accounting for 30 % of all the cases. 16 % patients had a recent dental procedure and 10 % had a recent surgical procedure. The most common infective organism was staphylococcus aureus (24%), followed by streptococcus viridians (20%). The most common indications for surgery were congestive heart failure (CHF) (52%), embolic phenomenon (18%) and septic shock (10%). Most common postoperative complication was respiratory failure (30%) followed by renal failure (24%) pacemaker implantation 22%; stroke 18%, bleeding 16% and GI bleeding 2 %. Seven out of 50 patients died during hospital course that accounts for 14% of the motility rate. CONCLUSIONS: Surgery for endocarditis continues to be challenging and associated with high operative mortality and morbidity. Age, shock, prosthetic valve endocarditis, impaired ventricular function, and recurrent infections adversely affect long-term survival.

Congenital long QT syndrome: A case report.

The congenital long QT syndrome (LQTS) is characterized by abnormally prolonged ventricular repolarization due to inherited defects in cardiac sodium and potassium channels, which predispose the patients to syncope, seizure like activity, ventricular arrhythmias, and sudden cardiac death. Early diagnosis and preventive treatment are instrumental in preventing sudden cardiac deaths in patients with the congenital LQTS. The diagnostic criteria for congenital LQTS are based on certain electrocardiographic findings, clinical findings and findings of epinephrine stress test. Recently genotype specific electrocardiographic pattern in the congenital LQTS has also been described. Recent studies suggest feasibility of genotype specific treatment of LQTS and, in near future, mutation specific treatment will probably become a novel approach to this potentially fatal syndrome. We describe one case that fulfilled the electrocardiographic, historical diagnostic criteria and epinephrine stress test suggestive of LQT syndrome.

QT dispersion as a predictor for arrhythmias in patients with acute ST elevation myocardial infarction.

AIMS AND OBJECTIVES: To study the effect of Heart Rate Variability (HRV) and QT dispersion (QTd) in patients presenting with Acute ST elevation myocardial infarction (STEMI). METHODS: This is a retrospective study conducted on patients admitted with the diagnosis of acute ST elevation myocardial infarction. In all 100 patients with acute myocardial infarction in one year were subjected to a complete evaluation in terms of history and examination. Besides routine investigations standard 12 lead ECG was evaluated in all cases on admission, after 4 hrs, 24 hrs, 48 hrs and on discharge. RESULTS: The most common presenting symptoms were chest pain (88%) and dyspnea (50%). Tachycardia was seen in 56% while congestive heart failure was present in 29% patients. Patients who died had a higher QTd in comparison to patients who survived. CONCLUSIONS: Markers of autonomic regulation of heart like QTd provides valuable information about the future course of events in a patient following acute STEMI which can be utilized to plan the future course of management in patients especially predisposed to adverse and catastrophic outcomes.