Neurogenic pulmonary edema after subarachnoid hemorrhage

Neurogenic pulmonary edema in subarachnoid hemorrhage: relevant clinical concepts

BACKGROUND

Subarachnoid hemorrhage (SAH) continues to be a condition that carries high rates of morbidity, mortality, and disability around the world. One of its complications is neurogenic pulmonary edema (NPE), which is mainly caused by sympathetic hyperactivity. Due to the complexity of the pathophysiological process and the unspecificity of the clinical presentation, it is little known by general practitioners, medical students and other health care workers not directly related to the neurological part, making the management of this chaotic condition difficult. This review aims to present recent evidence on clinical concepts relevant to the identification and management of NPE secondary to SAH.

MAIN BODY OF THE ABSTRACT

NPE is defined as a syndrome of acute onset following significant central nervous system (CNS) injury. Its etiology has been proposed to stem from the release of catecholamines that produce cardiopulmonary dysfunction, with this syndrome being associated with spinal cord injury, cerebrovascular disorders, traumatic brain injury, status epilepticus, and meningitis. NPE has long been considered a rare event; but it may occur more frequently, mainly in patients with SAH. There are two clinical presentations of NPE: the early form develops in the first hours/minutes after injury, while the late form presents 12-24 h after neurological injury. Clinical manifestations consist of non-specific signs of respiratory distress: dyspnea, tachypnea, hypoxia, pink expectoration, crackles on auscultation, which usually resolve within 24-48 h in 50% of patients. Unfortunately, there are no tools to make the specific diagnosis, so the diagnosis is by exclusion. The therapeutic approach consists of two interventions: treatment of the underlying neurological injury to reduce intracranial pressure and control sympathetic hyperactivity related to the lung injury, and supportive treatment for pulmonary edema.

SHORT CONCLUSION

SAH is a severe condition that represents a risk to the life of the affected patient due to the possible complications that may develop. NPE is one of these complications, which due to the common manifestation of a respiratory syndrome, does not allow early and accurate diagnosis, being a diagnosis of exclusion. Therefore, in any case of CNS lesion with pulmonary involvement, NPE should be suspected immediately.

Clinical Features of Neurogenic Pulmonary Edema in Patients with Subarachnoid Hemorrhage

OBJECTIVE

Neurogenic pulmonary edema (NPE) is a clinical syndrome characterized by acute onset after central nervous system injury. Here, we investigated the clinical features of NPE in patients with subarachnoid hemorrhage (SAH).

METHODS

We retrospectively analyzed a total of 350 patients with SAH who were treated at our hospital from April 2014 to September 2017. Patient demographics, aneurysm size and location, clinical characteristics, and patient outcomes were reviewed and compared between an NPE and a non-NPE group.

RESULTS

Sixteen patients (4.6%) presented with NPE at admission. Ten of these (62.5%) recovered from NPE immediately, and ventilatory support was withdrawn within 2 days from onset. A univariate analysis showed that patients with NPE were younger (P = 0.04), had a higher rate of vertebral artery dissection (P < 0.01), more severe World Federation of Neurosurgical Societies (WFNS) grades (P = 0.01), and lower systolic blood pressure on admission (P = 0.01). A multivariate analysis revealed significant differences in the frequency of vertebral artery dissection (odds ratio 4.83, 95% confidence interval 1.50-15.56, P < 0.01) and in WFNS grades (odds ratio 3.73, 95% confidence interval 1.02-13.66, P = 0.04) between the groups. No significant group differences were found in other factors including heart rate, radiographic sign (Fisher grade), aneurysm size and location, blood sample tests on admission, and neurologic outcomes.

CONCLUSIONS

Vertebral artery dissection and severe WFNS grade on admission were confirmed as significant risk factors for NPE. However, neurologic outcomes at discharge did not differ between groups, suggesting that poor outcomes due to NPE could be reduced by appropriate diagnosis and treatment.

Neurogenic pulmonary oedema secondary to vertebral artery dissection while playing tennis

We present a case of a patient who developed vertebral artery dissection (VAD) while playing tennis and presented with neurogenic pulmonary oedema. The case highlights two important points: acute pulmonary oedema as an unusual presenting feature of VAD and VAD, an important cause of stroke in young people, as being associated with playing low-impact sports such as tennis. These associations, independent of each other, are under-recognised and can lead to a delay in diagnosis.

Dramatic increases in blood glutamate concentrations are closely related to traumatic brain injury-induced acute lung injury

Traumatic brain injury-induced acute lung injury (TBI-ALI) is a serious complication after brain injury for which predictive factors are lacking. In this study, we found significantly elevated blood glutamate concentrations in patients with TBI or multiple peripheral trauma (MPT), and patients with more severe injuries showed higher blood glutamate concentrations and longer durations of elevated levels. Although the increase in amplitude was similar between the two groups, the duration was longer in the patients with TBI. There were no significant differences in blood glutamate concentrations in the patients with MPT with regard to ALI status, but the blood glutamate levels were significantly higher in the patients with TBI-ALI than in those without ALI. Moreover, compared to patients without ALI, patients with TBI showed a clearly enhanced inflammatory response that was closely correlated with the blood glutamate levels. The blood glutamate concentration was also found to be a risk factor (adjusted odds ratio, 2.229; 95% CI, 1.082–2.634) and was a better predictor of TBI-ALI than the Glasgow Coma Scale (GCS) score. These results indicated that dramatically increased blood glutamate concentrations were closely related to the occurrence of TBI-ALI and could be used as a predictive marker for “at-risk” patients.

Postoperative ICU management of patients after subarachnoid hemorrhage

PURPOSE OF REVIEW

This article reviews recent advances in the postoperative ICU management of patients after subarachnoid hemorrhage (SAH), especially with regards to hemodynamic management, methods of improving neurological outcomes, and management of cardiac and pulmonary complications.

RECENT FINDINGS

Several hemodynamic monitors and parameters may be useful for guiding volume therapy, including cardiac output, stroke volume variation monitoring, and global end-diastolic volume index. Early goal-directed hemodynamic therapy after SAH has recently been shown to improve clinical outcomes in patients with a poor clinical grade or coexisting cardiopulmonary complications. Recent laboratory and imaging modalities are being developed to identify patients at risk for developing vasospasm after SAH. Evidence for the use of various prophylactic adjuvant therapies to prevent vasospasm, including magnesium, phosphodiesterase 3 inhibitors, and therapeutic hypothermia, is emerging. Intrathecal administration of vasodilators or fibrinolytics may have offered advantages over systemic drug administration in the treatment of vasospasm. Pulmonary and cardiac complications are common after SAH, and are associated with an increased risk of mortality.

SUMMARY

The postoperative ICU period after SAH is associated with a significant morbidity and mortality risk, and recent studies have greatly contributed to our understanding of how to optimally manage these patients.