The Coronavirus disease (COVID-19) pandemic of 2019 has resulted in significant morbidity and mortality, especially from severe acute respiratory distress syndrome (ARDS). As of September 2022, more than 6.5 million patients have died globally, and up to 5% required intensive care unit treatment. COVID-19-associated ARDS (CARDS) differs from the typical ARDS due to distinct pathology involving the pulmonary vasculature endothelium, resulting in diffuse thrombi in the pulmonary circulation and impaired gas exchange. The National Institute of Health and the Society of Critical Care Medicine recommend lung-protective ventilation, prone ventilation, and neuromuscular blockade as needed. Further, a trial of pulmonary vasodilators is suggested for those who develop refractory hypoxemia. A review of the prior literature on inhaled pulmonary vasodilators in ARDS suggests only a transient improvement in oxygenation, with no mortality benefit. This narrative review aims to highlight the fundamental principles in ARDS management, delineate the fundamental differences between CARDS and ARDS, and describe the comprehensive use of inhaled pulmonary vasodilators. In addition, with the differing pathophysiology of CARDS from the typical ARDS, we sought to evaluate the current evidence regarding the use of inhaled pulmonary vasodilators in CARDS.

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Introduction: Phenazopyridine is an over-the-counter urinary analgesic commonly used to alleviate the burning and urgency associated with lower urinary tract infections. Methaemoglobinaemia is an uncommon adverse effect of phenazopyridine use. We report a case of methaemoglobinaemia in a patient prescribed daily phenazopyridine to treat urethral and bladder irritation caused by a chronic indwelling Foley catheter. Case description: A 55-year-old female resident of a long-term acute care facility with a chronic Foley, tracheostomy and ventilator-dependent respiratory failure was observed to have generalized dusky skin and hypoxia. Pulse oximetry was reading in the high 80s despite administration of 100% FiO2. ABG revealed paO2 of 451, oxyhaemoglobin level 75% and methaemoglobin level 22%. Medication review indicated that the patient was prescribed phenazopyridine 400 mg TID for the previous 2 months. This medication was discontinued. Considering she was chronically taking mirtazapine, she can increase risk of serotonin syndrome should she be administered first-line treatment with methylene blue. Vitamin C was thus instead administered as a second-line agent. Serial ABGs showed a rapid decline in methaemoglobin levels and an increase in oxyhaemoglobin within 2 days. Discussion: Acquired methaemoglobinaemia is a rare adverse effect of treatment with phenazopyridine. This risk increases when drug dosage and duration exceed manufacturer specifications. Treatment typically includes cessation of the offending drug and administration of methylene blue in severe cases. A thorough medication reconciliation should be performed prior to methylene blue initiation, as patients taking serotonergic medications (for example, MAOIs, SSRIs, SNRIs, TCAs) are at increased risk of serotonin toxicity with co-administration of methylene blue. In these instances, ascorbic acid/vitamin C can be chosen as an alternative treatment agent. Conclusion: Work-up of refractory hypoxia should involve a thorough review of medications as even some over-the-counter drugs can cause the fatal side effect of methaemoglobinaemia. Treatment with vitamin C should be considered over methylene blue if serotonergic medications have been recently prescribed in order to avoid risk of serotonin syndrome.

Introduction: Subclavian artery stenosis (SAS) is a manifestation of peripheral artery disease (PAD). Presentation varies, ranging from arm claudication and muscle fatigue to symptoms which reflect vertebrobasilar hypoperfusion, among which are syncope, ataxia and dysphagia. Although rare, severe bilateral SAS can exist and present as refractory hypotension. We describe a case of bilateral SAS masquerading as circulatory shock, or rather ‘pseudoshock’. Case Description: A 59-year-old female patient presented to the emergency department with complaints of dark stools. She was anaemic and hypotensive and therefore suspected to have an acute gastrointestinal bleed (GIB) with resultant haemorrhagic shock. Her hypotension was unresponsive to fluid resuscitation and blood transfusions. Bilateral upper extremity radial artery catheters confirmed low blood pressures. After her blood pressure failed to improve despite the addition of several vasopressors, a femoral artery catheter (FAC) was placed, which revealed significant hypertension discordant with the hypotension measured by the radial artery catheters. Review of CT angiography of the upper extremities revealed the presence of bilateral SAS which was deemed to be the aetiology of the falsely low blood pressure. Discussion: SAS should be suspected in patients with lower extremity PAD or a blood pressure (BP) differential of 15 mmHg or more between arms. When bilateral subclavian arteries are stenosed, this difference in BP may be concealed, making lower extremity BP measurements, as seen in non-invasive tests such as ankle brachial index (ABI) tests or through more invasive procedures such as FAC placement, critically important. Conclusion: Bilateral SAS may present as pseudo-hypotension. In cases of refractory shock of unclear aetiology, especially in patients with known PAD, a high index of suspicion is warranted for ‘pseudoshock’ secondary to severe vascular stenosis. Comparison of upper and lower extremity BP via invasive arterial catheters or non-invasive ABI tests can aid in the diagnosis of bilateral SAS.

Background The COVID-19 pandemic brought an unprecedented disruption to many hospital standard operating procedures including changing family visitation policies. As an infection control policy, most hospitals denied or limited visitors and patient families were updated via phone or video conferencing. There are several plausible reasons to suspect that altered communication techniques and heightened public awareness of critical illness during the pandemic impacted end of life care and decision making. Methods We conducted a retrospective observational cohort study from a tertiary care hospital to determine if more patients in the ICU were transitioned to comfort measures only (CMO) care during COVID than in the same period the year before when COVID had not yet arrived in the United States (“pre-pandemic”). Collected information included demographics (Table 1), reason for ICU, co-morbidities, code status at admission, length of ICU stay, cost of care during ICU admission, and disposition at discharge. All analyses began using the Kolmogorov -Smirnov test. Normally distributed continuous variables are compared between groups using the independent-samples t-test. Non-normally distributed continuous variables are compared between groups using the Mann-Whitney U test. Results There were no statistically significant differences in baseline demographic and clinical characteristics of patients admitted to the medical ICU during the pre-pandemic versus pandemic periods (Table 1). Among the 266 patients admitted during the pre-pandemic period, 11.7% (31/266) were discharged with CMO code status. Among the 160 patients admitted in the pandemic period, 8.8% (14/160) were discharged with CMO code status (Table 2). The median APACHE score was significantly higher in the pre-pandemic period ([median=18 (interquartile range = 11) compared to the pandemic period ([median=15 (interquartile range = 1), (Mann-Whitney U = 17146.50, p = .008). The cost of an ICU admission during the pandemic period increased 0.099%. Table 1Baseline demographic and clinical characteristics of patients admitted to the medical ICU pre- versus post-pandemic (n = 426).Table 2Discharge status code and outcomes of patients admitted to the medical ICU in the pre- versus post-pandemic (n = 426). Conclusion This study shows that despite the highmorbidity and mortality associated with COVID, during the study time periods, the limitation of in-person visitors did not have an impact on the frequency of patients transitioned to CMO or decreased hospital expenditure. Disclosures Tariq Cheema, MD, GSK,BI,ASTRA ZENECA,Regenoron: Honoraria.