Hemodynamic Effects of Ketamine Infusion in the Intensive Care Unit for Maintenance Sedation Compared With Propofol and Midazolam: A Retrospective Cohort Study.

Background: Sedation and analgesia in the intensive care unit (ICU) are major clinical challenges, and several continuous infusion medications have been used for these purposes. The use of these sedative medications has been associated with hemodynamic effects that complicate the patient's critical illness. Continuous ketamine infusion is an emerging sedative option that has been used more frequently in the ICU since 2017. The purpose of this study was to characterize the hemodynamic differences between 3 continuous sedative infusions: ketamine, propofol, and midazolam. Methods: For this single-center retrospective cohort study, we collected data for patients hospitalized between January 2015 and April 2020 at Saint Luke's Health System in Kansas City, Missouri. Adult patients in the ICU requiring a norepinephrine infusion and sedation were included. The change in norepinephrine requirement from baseline at 1 hour was the primary outcome. The change in vasopressor requirement at 3 and 30 hours after initiation of the infusion was also tabulated. Results: Sixty-eight critically ill patients with several types of shock requiring vasopressor support with norepinephrine were enrolled in our study. Patients who received ketamine had an increase in norepinephrine requirement compared to midazolam and propofol, although this difference was not statistically significant. Conclusion: In our study, continuous ketamine infusion did not reveal a statistically significant favorable hemodynamic effect compared with propofol and midazolam because of the small sample size. A trend toward an unfavorable hemodynamic effect is not expected, but large randomized trials are needed to further evaluate the hemodynamic effects of continuous ketamine infusion in the ICU.

Establishing a gradient between partial pressure of arterial carbon dioxide and end-tidal carbon dioxide in patients with acute respiratory distress syndrome.

End-tidal carbon dioxide (ETCO2) monitoring is useful in many situations. However, ETCO2 monitoring is unreliable in patients with acute respiratory distress syndrome (ARDS) due to widespread lung inflammation. In our study, we attempt to establish the gradient between the arterial pressure of carbon dioxide (PaCO2) and ETCO2 in patients with ARDS, which we defined as the PaETCO2 gradient. The main objective of the study was to establish a PaETCO2 gradient in each severity of ARDS. We analyzed 35 patients with ARDS and a total of 88 arterial blood gases were included. PaCO2, PaO2/FiO2 and ETCO2 were measured. Patients were stratified into mild, moderate and severe ARDS as classified by the Berlin ARDS criteria. PaCO2 and ETCO2 were compared at each severity stratification. The mean PaCO2 was 50.0, the mean ETCO2 was 26.6 and the gradient among all samples was 23.24 (±12.02). The mean gradient for each severity is as follows: mild: 19.3 (±9.9), moderate: 27.9 (±13.2) and severe: 23.9 (±7.8). The difference between the PaETCO2 gradient of the mild to moderate (p=0.001) and mild to severe groups (p=0.01) reached statistical significance. However, the difference between the moderate to severe groups did not reach statistical significance (p=0.48). We found the gradient between PaCO2 and ETCO2 in patients with ARDS is vast and tends to worsen with increasing severity of ARDS. This indicates that the gradient between the 2 may be used as an indicator of increasing severity of ARDS.

Tissue Plasminogen Activator Use in Cardiac Arrest Secondary to Fulminant Pulmonary Embolism.

BACKGROUND: Tissue plasminogen activator (tPA) is used emergently to dissolve thrombi in the treatment of fulminant pulmonary embolism. Currently, there is a relative contraindication to tPA in the setting of traumatic or prolonged cardiopulmonary resuscitation > 10 minutes because of the risk of massive hemorrhage. METHODS: Our single-center, retrospective study investigated patients experiencing cardiac arrest (CA) secondary to pulmonary embolus. We compared the effectiveness of advanced cardiac life support with the administration of tPA vs. the standard of care consisting of advanced cardiac life support without thrombolysis. The primary endpoint was survival to discharge. Secondary endpoints were return of spontaneous circulation (ROSC), major bleeding, and minor bleeding. RESULTS: We analyzed 42 patients, of whom 19 received tPA during CA. Patients who received tPA were not associated with a statistically significant increase in survival to discharge (10.5% vs. 8.7%, P = 1.00) or ROSC (47.4% vs. 47.8%, P = 0.98) compared to the control group. We observed no statistically significant difference between the groups in major bleeding events (5.3% in the tPA group vs. 4.3% in the control group, P = 1.00) and minor bleeding events (10.5% in the tPA group vs. 0.0% in the control group, P = 0.11). CONCLUSION: This study did not find a statistically significant difference in survival to discharge or in ROSC in patients treated with tPA during CA compared to patients treated with standard therapy. However, because no significant difference was found in major or minor bleeding, we suggest that the potential therapeutic benefits of this medication should not be limited by the potential for massive hemorrhage. Larger prospective studies are warranted to define the efficacy and safety profile of thrombolytic use in this population.

Correlation Between Partial Pressure of Arterial Carbon Dioxide and End Tidal Carbon Dioxide in Patients with Severe Alcohol Withdrawal.

BACKGROUND: Respiratory depression is a common adverse effect of benzodiazepine administration to patients with severe alcoholic withdrawal. This study was conducted to assess the value of end tidal carbon dioxide (ETCO2) levels compared to partial pressure of arterial carbon dioxide (PaCO2) levels in monitoring respiratory depression secondary to benzodiazepine treatment in patients with severe alcohol withdrawal. METHODS: We retrospectively analyzed 36 patients admitted to the intensive care unit for severe alcohol withdrawal who had been administered sedative agents. RESULTS: We observed a statistically significant correlation between PaCO2 and ETCO2 at time 1 (r=0.74, P<0.01) and time 3 (r=0.52, P=0.02) but not at time 2 (r=0.22, P=0.31). CONCLUSION: Our study confirms a positive correlation between PaCO2 and ETCO2 levels in patients experiencing severe alcohol withdrawal.

A Case of Tumor Lysis Syndrome in a Patient with Pancreatic Adenocarcinoma Treated with Low-Dose Gemcitabine.

BACKGROUND: Tumor lysis syndrome (TLS) is a common adverse consequence of treatment of high-grade hematologic malignancies that has been known to occur rarely in some solid tumors, including small cell lung cancer, breast cancer, colorectal cancer, neuroblastoma, ovarian cancer, and hepatocellular carcinoma. CASE REPORT: We present a case of TLS in a patient with pancreatic adenocarcinoma treated with one small dose of gemcitabine. To our knowledge, this phenomenon has only been described once prior in the medical literature and never with a reduced dose of chemotherapy. CONCLUSION: This case reveals the need for heightened awareness of TLS in patients with solid tumors, especially in patients with pancreatic adenocarcinoma.