Acute Respiratory Distress Syndrome in Patients with Subarachnoid Hemorrhage: Incidence, Predictive Factors, and Impact on Mortality

High-Grade Subarachnoid Hemorrhage - Beyond Guidelines

Subarachnnoid hemorrhage (SAH) present in a spectrum of clinical severity, from alert with a headache to comatose. High-grade SAH has higher mortality and risk for severe complications including acute respiratory distress syndrome (ARDS) and delayed cerebral ischemia (DCI). Existing treatment approaches for ARDS in SAH require special consideration because of potential impact on intracranial pressure and cerebral perfusion. DCI is a major cause of SAH morbidity and is often discordant with angiographic vasospasm. Current treatment approaches for DCI and vasospasm require further investigation to determine efficacy and risk/benefit. Nimodipine remains the only therapeutic that is proven to improve SAH outcome.

Disentangling the phenotypic patterns of hypertension and chronic hypotension

OBJECTIVE

2017 blood pressure (BP) categories focus on cardiac risk. We hypothesize that studying the balance between mechanisms that increase or decrease BP across the medical phenome will lead to new insights. We devised a classifier that uses BP measures to assign individuals to mutually exclusive categories centered in the upper (Htn), lower (Hotn) and middle (Naf) zones of the BP spectrum; and examined the epidemiologic and phenotypic patterns of these BP-categories.

METHODS

We classified a cohort of 832,560 deidentified electronic health records by BP-category; compared the frequency of BP-categories and four subtypes of Htn and Hotn by sex and age-decade; visualized the distributions of systolic, diastolic, mean arterial and pulse pressures stratified by BP-category; and ran Phenome-wide Association Studies (PheWAS) for Htn and Hotn. We paired knowledgebases for hypertension and hypotension and computed aggregate knowledgebase status (KB-status) indicating known associations. We assessed alignment of PheWAS results with KB-status for phecodes in the knowledgebase, and paired PheWAS correlations with KB-status to surface phenotypic patterns.

RESULTS

BP-categories represent distinct distributions within the multimodal distributions of systolic and diastolic pressure. They are centered in the upper, lower, and middle zones of mean arterial pressure and provide a different signal than pulse pressure. For phecodes in the knowledgebase, 85% of positive correlations align with KB-status. Phenotypic patterns for Htn and Hotn overlap for several phecodes and are separate for others. Our analysis suggests five candidates for hypothesis testing research, two where the prevalence of the association with Htn or Hotn may be under appreciated, three where mechanisms that increase and decrease blood pressure may be affecting one another's expression.

CONCLUSION

PairedPheWAS methods may open a phenome-wide path to disentangling hypertension and chronic hypotension. Our classifier provides a starting point for assigning individuals to BP-categories representing the upper, lower, and middle zones of the BP spectrum. 4.7 % of individuals matching 2017 BP categories for normal, elevated BP or isolated hypertension, have diastolic pressure < 60. Research is needed to fine-tune the classifier, provide external validation, evaluate the clinical significance of diastolic pressure < 60, and test the candidate hypotheses.

Contemporary management of aneurysmal subarachnoid haemorrhage. An update for the intensivist

Aneurysmal subarachnoid haemorrhage (aSAH) is a rare yet profoundly debilitating condition associated with high global case fatality and morbidity rates. The key determinants of functional outcome include early brain injury, rebleeding of the ruptured aneurysm and delayed cerebral ischaemia. The only effective way to reduce the risk of rebleeding is to secure the ruptured aneurysm quickly. Prompt diagnosis, transfer to specialized centers, and meticulous management in the intensive care unit (ICU) significantly improved the prognosis of aSAH. Recently, multimodality monitoring with specific interventions to correct pathophysiological imbalances has been proposed. Vigilance extends beyond intracranial concerns to encompass systemic respiratory and haemodynamic monitoring, as derangements in these systems can precipitate secondary brain damage. Challenges persist in treating aSAH patients, exacerbated by a paucity of robust clinical evidence, with many interventions showing no benefit when tested in rigorous clinical trials. Given the growing body of literature in this field and the issuance of contemporary guidelines, our objective is to furnish an updated review of essential principles of ICU management for this patient population. Our review will discuss the epidemiology, initial stabilization, treatment strategies, long-term prognostic factors, the identification and management of post-aSAH complications. We aim to offer practical clinical guidance to intensivists, grounded in current evidence and expert clinical experience, while adhering to a concise format.

Factors associated with acute respiratory distress syndrome in brain-injured patients: A systematic review and meta-analysis

PURPOSE

Acute respiratory distress syndrome (ARDS) is common in patients with acute brain injury admitted to the ICU. We aimed to identify factors associated with ARDS in this population.

METHODS

We searched MEDLINE, Embase, Cochrane Central, Scopus, and Web of Science from inception to January 14, 2022. Three reviewers independently screened articles and selected English-language studies reporting risk factors for ARDS in brain-injured adult patients. Data were extracted on ARDS incidence, adjusted and unadjusted risk factors, and clinical outcomes. Risk of bias was reported using the Quality in Prognostic Studies tool. Certainty of evidence was assessed using GRADE.

RESULTS

We selected 23 studies involving 6,961,284 patients with acute brain injury. The pooled cumulative incidence of ARDS after brain injury was 17.0% (95%CI 10.7-25.8). In adjusted analysis, factors associated with ARDS included sepsis (odds ratio (OR) 4.38, 95%CI 2.37-8.10; high certainty), history of hypertension (OR 3.11, 95%CI 2.31-4.19; high certainty), pneumonia (OR 2.69, 95%CI 2.35-3.10; high certainty), acute kidney injury (OR 1.44, 95%CI 1.30-1.59; moderate certainty), admission hypoxemia (OR 1.67, 95%CI 1.29-2.17; moderate certainty), male sex (OR 1.30, 95%CI 1.06-1.58; moderate certainty), and chronic obstructive pulmonary disease (OR 1.27, 95%CI 1.13-1.44; moderate certainty). Development of ARDS was independently associated with increased odds of in-hospital mortality (OR 3.12, 95% CI 1.39-7.00).

CONCLUSIONS

Multiple risk factors are associated with ARDS in brain-injured patients. These findings could be used to develop prognostic models for ARDS or as prognostic enrichment strategies for patient enrolment in future clinical trials.

Efficacy comparison of restrictive versus massive fluid resuscitation in patients with traumatic hemorrhagic shock

OBJECTIVE

To compare the therapeutic effect and safety of restrictive versus massive fluid resuscitation in patients with traumatic hemorrhagic shock (TSH).

METHODS

Ninety TSH patients treated in the ICU of the Second Affiliated Hospital of Zhejiang University School of Medicine from June 2020 to January 2021 were recruited for this retrospective study. Among them, 47 cases received restrictive fluid resuscitation (RFR) after admission who were considered as the observation group (OG), while the other 43 cases were given massive fluid resuscitation (MFR) who were treated as the control group (CG). The clinical indices, coagulation function, blood gas analysis, mortality within 72 h, duration of mechanical ventilation, and ICU stay were compared between the two groups, and the amount of resuscitation fluid given and complications that occurred during treatment were recorded. Multivariate logistic regression analysis was used to screen the independent risk factors for complications.

RESULTS

In comparison to the CG, the resuscitation time, infusion volume, and lactate level in the OG were lower after treatment, while the hemoglobin level and blood gas residual base value (BE) were higher. Besides, the activated partial thromboplastin time (APTT), thrombin time (TT) and prothrombin time (PT) levels and arterial blood carbon dioxide partial pressure (PaCO₂) in the OG were lower, while arterial blood oxygen partial pressure (PaO₂) and pH were higher. The duration of mechanical ventilation and ICU stay in the OG after treatment were lower, and there was no statistical difference in mortality and complication rates within 72 h. Lower mean arterial pressure (MAP), higher APACHE II (Acute Physiology and Chronic Health Evaluation II) and longer resuscitation time were independent risk factors for complications in patients with traumatic shock.

CONCLUSION

TSH treatment with RFR can effectively accelerate patients' resuscitation with less volume of infusion of resuscitation fluid, reduced time of mechanical ventilation and ICU hospitalization, and promote the recovery of coagulation function. It has good effects and is very suitable for clinical application.