西山 聖也

BACKGROUND: Cerebrospinal fluid (CSF) levels of orexin show a cyclic diurnal variation in healthy subjects, which is diminished in patients with certain diseases. However, possible circadian variations in orexin levels in critically ill patients remain unknown. In this study, we evaluated the orexin concentrations in the CSF and their diurnal variation in patients undergoing thoracic aortic aneurysm repair with lumbar intrathecal catheterization for CSF drainage after non-neurosurgery. METHODS: Eligible patients with a lumbar intrathecal catheter placed for CSF drainage following aortic surgery at a single-center ICU between September 2019 and February 2020 were included. Catheters were placed before anesthesia induction, and CSF was collected at the time of catheter placement, ICU admission, and daily at 6:00, 12:00, 18:00, and 24:00 until the catheter was removed or for up to 5 days after admission to the ICU. RESULTS: Three patients (Patients A, B, and C) who underwent thoracic aortic aneurysm repair were included. Patients B and C received sedatives or hypnotics during the orexin measurement period. The baseline orexin levels for Patients A, B, and C were 219.9, 312.3, and 403.8 pg/mL, while the mean orexin levels were 319.4 ± 82.6, 372.4 ± 56.0, and 306.3 ± 48.3 pg/mL, respectively. For all three patients, orexin levels showed diurnal variations, but no consistent periodic changes. CONCLUSION: CSF orexin concentrations for patients undergoing thoracic aortic aneurysm repair in the ICU were within the reported range compared to those of previously reported healthy subjects; however, consistent periodic diurnal variations were not observed.

BACKGROUND: Tracking preload dependency non-invasively to maintain adequate tissue perfusion in the perioperative period can be challenging.The effect of phenylephrine on stroke volume is dependent upon preload. Changes in stroke volume induced by phenylephrine administration can be used to predict preload dependency. The change in the peripheral perfusion index derived from photoplethysmography signals reportedly corresponds with changes in stroke volume in situations such as body position changes in the operating room. Thus, the peripheral perfusion index can be used as a non-invasive potential alternative to stroke volume to predict preload dependency. Herein, we aimed to determine whether changes in perfusion index induced by the administration of phenylephrine could be used to predict preload dependency. METHODS: We conducted a prospective single-centre observational study. The haemodynamic parameters and perfusion index were recorded before and 1 and 2 min after administering 0.1 mg of phenylephrine during post-induction hypotension in patients scheduled to undergo surgery. Preload dependency was defined as a stroke volume variation of ≥ 12% before phenylephrine administration at a mean arterial pressure of < 65 mmHg. Patients were divided into four groups according to total peripheral resistance and preload dependency. RESULTS: Forty-two patients were included in this study. The stroke volume in patients with preload dependency (n = 23) increased after phenylephrine administration. However, phenylephrine administration did not impact the stroke volume in patients without preload dependency (n = 19). The perfusion index decreased regardless of preload dependency. The changes in the perfusion index after phenylephrine administration exhibited low accuracy for predicting preload dependency. Based on subgroup analysis, patients with high total peripheral resistance tended to exhibit increased stroke volume following phenylephrine administration, which was particularly prominent in patients with high total peripheral resistance and preload dependency. CONCLUSION: The findings of the current study revealed that changes in the perfusion index induced by administering 0.1 mg of phenylephrine could not predict preload dependency. This may be attributed to the different phenylephrine-induced stroke volume patterns observed in patients according to the degree of total peripheral resistance and preload dependency. TRIAL REGISTRATION: University Hospital Medical Information Network (UMIN000049994 on 9/01/2023).

INTRODUCTION: There are few reports describing the association of naldemedine with defecation in critically ill patients with opioid-induced constipation. The purpose of this study was to determine whether naldemedine is associated with earlier defecation in critically ill patients with opioid-induced constipation. METHODS: In this retrospective cohort study, patients admitted to the Intensive Care Unit (ICU) without defecation for 48 hours while receiving opioids were eligible for enrollment. The primary endpoint was the time of the first defecation within 96 hours after inclusion. Secondary endpoints included presence of diarrhea, duration of mechanical ventilation, ICU length of stay, ICU mortality, and in-hospital mortality. The Cox proportional hazard regression analysis with time-dependent covariates was used to evaluate the association naldemedine with earlier defecation. RESULTS: A total of 875 patients were enrolled and were divided into 63 patients treated with naldemedine and 812 patients not treated. Defecation was observed in 58.7% of the naldemedine group and 48.8% of the no-naldemedine group during the study (p = 0.150). The naldemedine group had statistically significantly prolonged duration of mechanical ventilation (8.7 days vs 5.5 days, p < 0.001) and ICU length of stay (11.8 days vs 9.2 days, p = 0.001) compared to the no-naldemedine group. However, the administration of naldemedine was significantly associated with earlier defecation [hazard ratio:2.53; 95% confidence interval: 1.71-3.75, p < 0.001]. CONCLUSION: The present study shows that naldemedine is associated with earlier defecation in critically ill patients with opioid-induced constipation.

BACKGROUND: It has been 50 years since the pulmonary artery catheter was introduced, but the actual use of pulmonary artery catheters in recent years is unknown. Some randomized controlled trials have reported no causality with mortality, but some observational studies have been published showing an association with mortality for patients with cardiogenic shock, and the association with a pulmonary artery catheter and mortality is unknown. The aim of this study was to investigate the utilization of pulmonary artery catheters (PACs) in the intensive care unit (ICU) and to examine their association with mortality, taking into account differences between hospitals. METHODS: This is a retrospective analysis using the Japanese Intensive care PAtient Database, a multicenter, prospective, observational registry in Japanese ICUs. We included patients aged 16 years or older who were admitted to the ICU for reasons other than procedures. We excluded patients who were discharged within 24 h or had missing values. We compared the prognosis of patients with and without PAC. The primary outcome was hospital mortality. We performed propensity score analysis to adjust for baseline characteristics and hospital characteristics. RESULTS: Among 184,705 patients in this registry from April 2015 to December 2020, 59,922 patients were included in the analysis. Most patients (94.0%) with a PAC in place had cardiovascular disease. There was a wide variation in the frequency of PAC use between hospitals, from 0 to 60.3% (median 14.4%, interquartile range 2.2-28.6%). Hospital mortality was not significantly different between the PAC use group and the non-PAC use group in patients after adjustment for propensity score analysis (3.9% vs 4.3%; difference, - 0.4%; 95% CI - 1.1 to 0.3; p = 0.32). Among patients with cardiac disease, those with post-open-heart surgery and those in shock, hospital mortality was also not significantly different between the two groups (3.4% vs 3.7%, p = 0.45, 1.7% vs 1.7%, p = 0.93, 4.8% vs 4.9%, p = 0.87). CONCLUSIONS: The frequency of PAC use varied among hospitals. PAC use for ICU patients was not associated with lower hospital mortality after adjusting for differences between hospitals.

Pulmonary tumor thrombotic microangiopathy (PTTM) is a high-mortality disease that is difficult to diagnose clinically. Our patient was an 80-year-old woman who came to us due to symptoms of increasing dyspnea. A clinical evaluation showed that she had hypoxemia and pulmonary arterial hypertension without any abnormalities in the major pulmonary arteries, bronchi, or alveoli. A lung perfusion scan showed multiple wedge-shaped perfusion defects. Further examination revealed adenocarcinoma in her right parotid gland with metastasis to the submandibular lymph nodes. We diagnosed her to have PTTM caused by a parotid tumor. The patient survived for 11 months with chemotherapy. An early antemortem diagnosis by minimally invasive examinations will help PTTM patients to survive longer.