TO THE EDITOR: We read with great interest the article by Hosmann et al.1(Hosmann A, Angelmayr C, Hopf A, et al. Detrimental effects of intrahospital transport on cerebral metabolism in patients suffering severe aneurysmal subarachnoid hemorrhage.J Neurosurg.Published online March 12, 2021. doi:10.3171/2020.8.JNS202280). The authors meticulously conducted a study to quantify the impact of intrahospital transport for imaging in patients with aneurysmal subarachnoid hemorrhage (aSAH), with a particular focus on cerebral metabolism.1
The authors interestingly found that longer intrahospital transport time and horizontal positioning during CT scanning led to immediate intracranial hypertension and increased cerebral glycerol, suggesting neuronal injury.1The hemodynamic lability of patients with SAH is caused by impaired cerebral flow autoregulation following SAH, making these patients particularly vulnerable to fluctuations in cerebral perfusion pressure. This in turn induces cerebral hypoxia and metabolic crisis.2Based on these findings, the authors reiterate that an inadequate in-hospital transport can lead to poorer outcomes despite the best treatment options in patients with SAH.
These adverse conditions are more profound in middle- or low-income countries (MLICs) where nonstandardized in-hospital practices and protocols are combined with limited infrastructure in neurocritical care.3,4Studies have shown that these deficiencies may be even higher during interinstitutional transports in such resource-restricted settings.5A significant number of hospitals in MLICs do not have elevators for medical use and thus use ramps with an average incline of 45°. An inappropriate positioning while moving the stretcher or bed on these steep ramps exposes the patients to much higher risk. In these centers, which are built over several stages, the new radiology units with higher space requirements are often located at a considerable distance from the emergency or inpatient wards. The result is that the intrahospital transport time is longer than 25 to 30 minutes. We believe that this is much longer than the time evaluated by Hosmann et al.,1considering the pathophysiological mechanisms proposed. These two aspects have an additive effect that may represent a deleterious impact on neuronal tissue and function, and ultimately, an increase in hospital stay, worse patient prognosis, and probable increase in mortality.
On the other hand, certain studies have highlighted problems with the coordination of safe hospital patient transport.5,6These range from the lack of transport vehicles to the paucity of emergency equipment in them, which can be further compounded by the presence of drivers without any emergency medical training who are unaccompanied by physicians or paramedics.5,6A stark example of poor interdepartmental coordination is seen in many centers in which a ventilated or a sick patient reaches the radiology suite in the middle of an ongoing procedure and then has to wait for a considerable period of time before undergoing imaging. All of these factors adversely affect the safe transfer of patients, including those with SAH.
Having said that, the findings of this study need to be interpreted given the complex dynamics of cerebral autoregulation and vasospasm leading to delayed cerebral ischemia (DCI) following aSAH. In this study, intrahospital transport was performed at a mean interval of 9.6 ± 5.6 days after aSAH. This is the time for peak vasospasm after aSAH. Studies have reflected that, compared with vasospasm, early dysautoregulation within 5 days after aSAH is more predictive of DCI.7,8Whether the observed effects in this study reflect effects due to vasospasm or due to dysregulation of cerebral autoregulation should be explored in future studies. Furthermore, the median Hunt and Hess grade in the present study was 4, and the study involved patients with severe aSAH. Studies have shown that dysregulation of cerebral autoregulation, even in patients with good-grade aSAH, can occur if surgery is performed 3–7 days after bleeding.9Other factors such as hydrocephalus also contribute to cerebral dysautoregulation.10
In conclusion, there is a need to carry out multicenter studies, mainly in MLICs, as is the case in Latin America and the Caribbean, to evaluate the real impact of the hypothesis proposed and to create evidence that will force a change in institutional policies, health systems, and infrastructure financing. These will be vital in order to establish safety measures for intrahospital and interinstitutional transport of patients with SAH and, ultimately, in patients who need neurocritical care, and to improve the prognosis of these patients. The present study also highlights the use of a portable CT scanner and other bedside diagnostic technologies to minimize the transfer of critically ill neurosurgical patients.
Disclosures
The authors report no conflict of interest.
References
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1 ↑
HosmannA,AngelmayrC,HopfA,et al.Detrimental effects of intrahospital transport on cerebral metabolism in patients suffering severe aneurysmal subarachnoid hemorrhage.J Neurosurg.Published online March 12, 2021. doi:https://doi.org/10.3171/2020.8.JNS202280
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2 ↑
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7 ↑
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8 ↑
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9 ↑
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10 ↑
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