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Alex B. Valadka, Jaclyn S. Valadka, Patrick R. Valadka and Patricia C. Valadka

The theme of the 2018 American Association of Neurological Surgeons Annual Meeting was “The Privilege of Service.” In the current climate of rapid change in healthcare delivery and increasing pressure on physicians, this theme was chosen to remind us of our true priorities and of the amazing opportunities that we have as neurosurgeons. In parallel to the classic triple-threat practitioner who excels in teaching, research, and clinical care, future neurosurgeons will need to acquire mastery in three areas of service, which have been summarized as the three A’s: administration, advocacy, and altruism. The blessings that we enjoy afford us a platform from which we can take advantage of the many opportunities to experience the privilege of serving others.

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Alex B. Valadka, Andrew I. R. Maas and Franco Servadei

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Roman Hlatky, Alex B. Valadka and Claudia S. Robertson

Arterial hypotension and intracranial hypertension are detrimental to the injured brain. Although artificial elevation of cerebral perfusion pressure (CPP) has been advocated as a means to maintain an adequate cerebral blood flow (CBF), the optimal CPP for the treatment of severe traumatic brain injury (TBI) remains unclear. In addition, CBF evolves significantly over time after TBI, and CBF may vary considerably in patient to patient. For these reasons, a more useful approach may be to consider the optimal CPP in an individual patient at any given time, rather than having an arbitrary goal applied uniformly to all patients. Important information for optimizing CBF is provided by monitoring intracranial pressure in combination with assessment of the adequacy of CBF by using global indicators (for example, jugular oximetry), supplemented when appropriate by local data, such as brain tissue oxygen tension.

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Manuela Cormio, Alex B. Valadka and Claudia S. Robertson

Object. The aim of this study was to investigate the incidence of elevated (≥ 75%) jugular venous oxygen saturation (SjvO2) and its relationship to cerebral hemodynamic and metabolic parameters and to outcome after severe head injury.

Methods. Data from 450 severely head injured patients admitted to the Neurosurgical Intensive Care Unit of Ben Taub General Hospital were analyzed retrospectively. The SjvO2 was measured in blood obtained from indwelling jugular bulb catheters. Patients were classified into the following categories: high (Group I), normal (Group II), or low SjvO2 (Group III) if their mean SjvO2 over the duration of monitoring was 75% or higher, 74 to 56%, or 55% or lower, respectively.

A high SjvO2 occurred in 19.1% of patients. There was no consistent relationship between SjvO2 and simultaneous cerebral blood flow (CBF) or cerebral perfusion pressure measurements. Compared with Groups II and III, the patients in Group I had a significantly higher CBF and lower cerebral metabolic rate of oxygen (CMRO2). In Group I, the outcomes were death or persistent vegetative state in 48.8% of patients and severe disability in 25.6%. These outcomes were significantly worse than for patients in Group II. Within Group I, the patients with a poor neurological outcome were older and more likely to have suffered a focal head injury; they demonstrated a lower CMRO2 and a greater rate of cerebral lactate production than the patients who attained a favorable outcome.

Conclusions. Posttraumatic elevation of SjvO2 is common but cannot be automatically equated with hyperemia. Instead, elevated SjvO2 is a heterogeneous condition that is associated with poor outcome after head injury and may carry important implications for the management of comatose patients.

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Manuela Cormio, Alex B. Valadka and Claudia S. Robertson

Object

The aim of this study was to investigate the incidence of elevated (≥ 75%) jugular venous oxygen saturation (SjvO2) and its relationship to cerebral hemodynamic and metabolic parameters and to outcome after severe head injury.

Methods

Data from 450 severely head injured patients admitted to the Neurosurgical Intensive Care Unit of Ben Taub General Hospital were analyzed retrospectively. The SjvO2 was measured in blood obtained from indwelling jugular bulb catheters. Patients were classified into the following categories: high (Group I), normal (Group II), or low SjvO2 (Group III) if their mean SjvO2 over the duration of monitoring was 75% or higher, 74 to 56%, or 55% or lower, respectively.

A high SjvO2 occurred in 19.1% of patients. There was no consistent relationship between SjvO2 and simultaneous cerebral blood flow (CBF) or cerebral perfusion pressure measurements. Compared with Groups II and III, the patients in Group I had a significantly higher CBF and lower cerebral metabolic rate of oxygen (CMRO2). In Group I, the out- comes were death or persistent vegetative state in 48.8% of patients and severe disability in 25.6%. These outcomes were significantly worse than for patients in Group II. Within Group I, the patients with a poor neurological outcome were older and more likely to have suffered a focal head injury; they demonstrated a lower CMRO2 and a greater rate of cerebral lactate production than the patients who attained a favorable outcome.

Conclusions

Posttraumatic elevation of SjvO2 is common but cannot be automatically equated with hyperemia. Instead, elevated SjvO2 is a heterogeneous condition that is associated with poor outcome after head injury and may carry important implications for the management of comatose patients.

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Alex B. Valadka, Yu Furuya, Roman Hlatky and Claudia S. Robertson

The disturbance of normal mechanisms of oxygen delivery and metabolism is a hallmark of severe traumatic brain injury (TBI). In the past, investigations into the status of cerebral oxygen metabolism depended on changes in the differences in oxygen content between arterial and jugular venous blood. The development of jugular venous oximetry permitted continuous monitoring of jugular venous oxygen saturation, thereby overcoming earlier limitations caused by intermittent sampling. Neuromonitoring techniques that utilize only jugular vein sampling provide information only about global cerebral metabolism, but direct measurement of brain tissue oxygen tension via intraparenchymal probes makes possible the assessment of regional cerebral oxygen metabolism. Regional and global neuromonitoring techniques are not competitive or mutually exclusive. Rather, they are best regarded as complementary, with each providing valuable information that has a direct bearing on patient outcomes. The authors review the currently available techniques used in the monitoring of cerebral oxidative metabolism in patients who have sustained severe TBI.

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Charles F. Opalak, Rafael A. Vega, Jodi L. Koste, R. Scott Graham and Alex B. Valadka

The Department of Neurosurgery at the Medical College of Virginia/Virginia Commonwealth University (VCU) celebrates its 100th anniversary in 2019. It was founded by C. C. Coleman, who directed the US Army School of Brain Surgery during World War I and was one of the original members of the Society of Neurological Surgeons. Coleman began a residency program that was among the first four such programs in the United States and that produced such prominent graduates as Frank Mayfield, Gayle Crutchfield, and John Meredith. Neurosurgery at VCU later became a division under the medical school’s surgery department. Division chairs included William Collins and Donald Becker. It was during the Becker years that VCU became a leading National Institutes of Health–funded neurotrauma research center. Harold Young oversaw the transition from division to department and expanded the practice base of the program. In 2015, Alex Valadka assumed leadership and established international collaborations for research and education. In its first 100 years, VCU Neurosurgery has distinguished itself as an innovator in clinical research and an incubator of compassionate and service-oriented physicians.

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Roman Hlatky, Alex B. Valadka, Shankar P. Gopinath and Claudia S. Robertson

Object

Increasing PaO2 can increase brain tissue PO2 (PbtO2). Nevertheless, the small increase in arterial O2 content induced by hyperoxia does not increase O2 delivery much, especially when cerebral blood flow (CBF) is low, and the effectiveness of hyperoxia as a therapeutic intervention remains controversial. The purpose of this study was to examine the role of regional (r)CBF at the site of the PO2 probe in determining the response of PbtO2 to induced hyperoxia.

Methods

The authors measured PaO2 and PbtO2 at baseline normoxic conditions and after increasing inspired O2 concentration to 100% on 111 occasions in 83 patients with severe traumatic brain injury in whom a stable xenon–enhanced computed tomography measurement of CBF was available. The O2 reactivity was calculated as the change in PbtO2 × 100/change in PaO2.

Results

The O2 reactivity was significantly different (p < 0.001) at the 5 levels of rCBF (<10, 11–15, 16–20, 21–40, and > 40 ml/100 g/min). When rCBF was < 20 ml/100 g/min, the increase in PbtO2 induced by hyperoxia was very small compared with the increase that occurred when rCBF was > 20 ml/100 g/min.

Conclusions

Although the level of CBF is probably only one of the factors that determines the PbtO2 response to hyperoxia, it is apparent from these results that the areas of the brain that would most likely benefit from improved oxygenation are the areas that are the least likely to have increased PbtO2.

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John Dickerson, Alex B. Valadka, Tina LeVert, Kimberly Davis, Mary Kurian and Claudia S. Robertson

Object. The number of patients waiting for organ transplantation continues to grow, while organs are donated by very few of the thousands of potential donors who die every year. The authors' neurosurgical intensive care unit (NICU) has worked closely with coordinators from the local organ procurement organization (OPO) for many years. In this study, the authors analyze donation rates in the NICU and discuss factors that may be important in maximizing these rates.

Methods. All referrals from the NICU to the OPO from 1996 to 1999 were analyzed. Of the 180 referrals, 98 patients were found to be medically suitable as potential donors. Another 15 patients died of hemodynamic collapse shortly after admission to the NICU. If one assumes that all 15 patients would have been suitable donors, the unsuccessful resuscitation rate becomes 15 (13.3%) of 113. Of the 98 eligible donors, consent was obtained and organs or tissue were recovered in 72, yielding a successful organ procurement rate of 73.5%.

Conclusions. Close working relationships among physicians, nurses, and OPO coordinators can result in higher donation rates than have been reported previously. Aggressive resuscitation and stabilization of all patients, early identification of potential organ donors, prompt declaration of brain death, and attempts by the OPO coordinator to build rapport with families are all important factors that may increase donation rates. Because most organ donors have sustained catastrophic intracranial events, neurosurgeons are uniquely positioned to influence organ donation policies at their hospitals and thus to salvage some benefit from tragic cases of overwhelming brain injury.