Usability and Tolerability of Virtual Reality-Based Cognitive Stimulation in Healthy Elderly Volunteers-A Feasibility Clinical Trial.

Background: The aim of the current pilot study was to evaluate the usability, acceptability, and tolerability of virtual reality (VR)-based cognitive stimulation exercises (CSEs) in healthy young versus old populations before health care integration. A secondary aim was to assess the accuracy of VR games as a proxy for cognitive stimulation, specifically for attention. VR-based CSEs promise to improve attention and brain function through varied learning systems. Methods: This is a Phase 1 feasibility clinical trial at a single center. It involves 30 healthy volunteers randomly selected using the American Society of Anesthesiologists (ASA) physical status classification system. Participants fall into ASA 1 (age >18-35 years, n = 15) or ASA 2 (age >60 years, n = 15) categories. All participants tested the ReCognitionVR-based CSEs. Feasibility criterion: Participants in each group were monitored for completion of 20 minutes of VR-based CSEs. Acceptability criterion: Proportion of participants with system usability scale (SUS) >35 or SUS score of 87.5. Safety (tolerability) monitoring: Sessions were monitored for neurological, cardiovascular, or pulmonary adverse events (AEs). Safety criterion: No more than 10% of sessions stopped due to neurological, cardiovascular, or pulmonary AEs. Results: The primary outcome (feasibility) of ReCognitionVR-based CSEs was 100%. For the secondary outcome (acceptability), there was no group difference in SUS scores (ASA 1 = 88.17 ± 12.83 vs. ASA 2 = 88.39 ± 10.22, P = 0.81). For the tertiary outcome (safety), mild transient uneasiness was reported by two (13.4%) ASA 1 participants (resolved in 2 minutes), and one (6.67%) ASA 1 participant experienced a temporary >20% increase in blood pressure from baseline. No ASA 2 participants had AEs. Conclusion: The feasibility, acceptability, and safety of ReCognitionVR-based CSEs in healthy elderly volunteers are acceptable, indicating that the evaluation of the ReCognitionVR-based CSEs in hospitalized patients is reasonable.

Prevalence of Delirium After Abdominal Surgery and Association With Ketamine: A Retrospective, Propensity-Matched Cohort Study.

IMPORTANCE: Delirium is a common postoperative complication for older patients in the ICU. Ketamine, used primarily as an analgesic, has been thought to prevent delirium. OBJECTIVE: Determine the prevalence and association of delirium with low-dose ketamine use in ICU patients after abdominal surgery. DESIGN: Single-center, retrospective, propensity-matched cohort study. SETTING: Eight hospital academic medical center. PATIENTS: Cohort comprising 1836 patients admitted to the ICU after abdominal surgery between June 23, 2018 and September 1, 2022. MAIN OUTCOMES AND MEASURES: Propensity score matching (PSM) with a 3:1 ratio between no-ketamine use and ketamine use was performed through a greedy algorithm (caliper of 0.005). Outcomes of interest included: delirium (assessed by Confusion Assessment Method-ICU), mean pain score (Numeric Pain Scale or Critical Care Pain Observation Tool score as available), mean opioid consumption (morphine milligram equivalents), length of stay (d), and mortality. RESULTS: Prevalence of delirium was 47.71% (95% CI, 45.41-50.03%) in the cohort. Of 1836 patients, 120 (6.54%) used low-dose ketamine infusion. After PSM, the prevalence of delirium was 56.02% (95% CI, 51.05-60.91%) in all abdominal surgery patients. The ketamine group had 41% less odds of delirium (odds ratio [OR] = 0.59; 95% CI, 0.37-0.94; p = 0.026) than patients with no-ketamine use. Patients with ketamine use had higher mean pain scores (3.57 ± 2.86 vs. 2.21 ± 2.09, p < 0.001). In the subgroup analysis, patients in the ketamine-use group 60 years old or younger had 64% less odds of delirium (OR = 0.36; 95% CI, 0.13-0.95; p = 0.039). The mean pain scores were higher in the ketamine group for patients 60 years old or older. There was no significant difference in mortality and opioid consumption. CONCLUSIONS AND RELEVANCE: Low-dose ketamine infusion was associated with lower prevalence of delirium in ICU patients following abdominal surgery. Prospective studies should further evaluate ketamine use and delirium.

ICU Delirium in Cardiac Patients.

Delirium is a prevalent complication in critically ill medical and surgical cardiac patients. It is associated with increased morbidity and mortality, prolonged hospitalizations, cognitive impairments, functional decline, and hospital costs. The incidence of delirium in cardiac patients varies based on the criteria used for the diagnosis, the population studied, and the type of surgery (cardiac or not cardiac). Delirium experienced when cardiac patients are in the intensive care unit (ICU) is likely preventable in most cases. While there are many protocols for recognizing and managing ICU delirium in medical and surgical cardiac patients, there is no homogeneity, nor are there established clinical guidelines. This review provides a comprehensive overview of delirium in cardiac patients and highlights its presentation, course, risk factors, pathophysiology, and management. We define cardiac ICU patients as both medical and postoperative surgical patients with cardiac disease in the ICU. We also highlight current controversies and future considerations of innovative therapies and nonpharmacological and pharmacological management interventions. Clinicians caring for critically ill patients with cardiac disease must understand the complex syndrome of ICU delirium and recognize the impact of delirium in predicting long-term outcomes for ICU patients.

Carboxyhemoglobinemia in Critically Ill Coronavirus Disease 2019 Patients.

Carboxyhemoglobinemia is a common but a serious disorder, defined as an increase in carboxyhemoglobin level. Unfortunately, there are few data on carboxyhemoglobinemia in coronavirus disease 2019 (COVID-19) patients. Therefore, our study aimed to evaluate the incidence and etiologies of carboxyhemoglobinemia in COVID-19 patients and determine any association between carboxyhemoglobinemia and novel coronavirus infection. A retrospective chart review was performed at an academic medical center for all inpatient COVID-19 cases with either single or serial carboxyhemoglobin (COHb) levels from March 2020 through August 2020.Our study demonstrates that carboxyhemoglobinemia in COVID-19 patients is due to sepsis, hemolysis, and cytokine storm, triggered by the novel coronavirus infection sequela and is not directly from the virulence of novel coronavirus. Given the coexisting illnesses in critically ill COVID-19 patients, it is impossible to establish if coronavirus virulence was the culprit of elevated COHb levels. Moreover, our study found a high incidence of carboxyhemoglobinemia in critically ill COVID-19 patients. The oxygen saturation measured by pulse oximetry can be inaccurate and unreliable; however, our study could not demonstrate any uniform results on the discrepancy between oxygen saturation measured by pulse oximetry and arterial blood gas. In this study, COHb levels were measured using a CO-oximeter. Therefore, we recommend monitoring the COHb level routinely in critically ill COVID-19 patients to allow more effective and prompt treatment.

Unexplained Methemoglobinemia in Coronavirus Disease 2019: A Case Report.

Methemoglobinemia is a rare disorder of the blood in which there is an increase in methemoglobin, which occurs when hemoglobin is present in the oxidized form. Methemoglobin impairs hemoglobin's ability to transport oxygen, produces functional anemia, and leads to tissue hypoxia. We report the successful management of a case of refractory hypoxia due to acutely acquired methemoglobinemia in a patient undergoing treatment for coronavirus disease 2019 (COVID-19) pneumonia. The cause of methemoglobinemia in this patient remains unknown. Hypoxia and methemoglobinemia did not respond to methylene blue and required administration of packed red blood cell transfusions.