Postoperative Neurological Injury Research Articles

Radiological properties of neurological injury following acute type A aortic dissection repair

ObjectiveThe study objective was to assess the radiological properties of acute type A aortic dissection–related neurological injuries and identify predictors of neurological injury. MethodsOur single-center, retrospective, observational study included all patients who underwent acute type A aortic dissection repair between January 1998 and December 2021. Multivariable analyses and Cox regression were performed to identify predictors of embolic lesions, watershed lesions, neurological injury, 30-day mortality, and late mortality. ResultsA total of 538 patients were included. Of these, 120 patients (22.3%) experienced postoperative neurological injury; 74 patients (13.8%) had postoperative stroke, and 36 patients (6.8%) had postoperative coma. The 30-day mortality was 22.7% in the neurological injury group versus 5.8% in the no neurological injury group (P < .001). We identified several independent predictors of neurological injury. Cerebral malperfusion (odds ratio, 2.77; 95% confidence interval, 1.53-5.00), systemic hypotensive shock (odds ratio, 1.97; 95% confidence interval, 1.13-3.43), and aortic arch replacement (odds ratio, 3.08; 95% confidence interval, 1.17-8.08) predicted embolic lesions. Diabetes mellitus (odds ratio, 5.35; 95% confidence interval, 1.85-15.42), previous cardiac surgery (odds ratio, 8.62; 95% confidence interval, 1.47-50.43), duration of hypothermic circulatory arrest (odds ratio, 1.05; 95% confidence interval, 1.01-1.08), cardiopulmonary bypass time (odds ratio, 1.01; 95% confidence interval, 1.00-1.01), ascending aortic/arch cannulation (odds ratio, 5.68; 95% confidence interval, 1.88-17.12), and left ventricular cannulation (odds ratio, 17.81; 95% confidence interval, 1.69-188.01) predicted watershed lesions. Retrograde cerebral perfusion (odds ratio, 0.28; 95% confidence interval, 0.01-0.84) had a protective effect against watershed lesions. ConclusionsIn this study, we demonstrated that the radiological features of neurological injury may be as important as clinical characteristics in understanding the pathophysiology and causality behind neurological injury related to acute type A aortic dissection repair.

Carbon dioxide flooding to reduce postoperative neurological injury following surgery for acute type A aortic dissection: a prospective, randomised, blinded, controlled clinical trial, CARTA study protocol - objectives and design

IntroductionNeurological complications after surgery for acute type A aortic dissection (ATAAD) increase patient morbidity and mortality. Carbon dioxide flooding is commonly used in open-heart surgery to reduce the risk of...

Postoperative Neurological Deficits with Incidence and the Various Arterial Territories Involved in Patients Undergoing Congenital Cardiac Surgery: A Single-center Analysis

Introduction: The incidence and pattern of neurological complications after congenital cardiac surgery have been changing over the years due to improvement in surgical technique and perioperative management. The aim of this study was to evaluate the incidence and pattern of neurological injury in our institute. Materials and Methods: We retrospectively reviewed all pediatric patients who underwent noncontrast computed tomography of the brain for suspected postoperative neurological injury occurring during the 1st week after pediatric cardiac surgery between April 2016 and February 2020. We identified neurological injury as patients having ischemic infarct and intracranial hemorrhage. Results: A total of 2971 pediatric cardiac surgeries were performed at our institute. Sixty-seven patients (2.25%) developed neurological injury. Fifty-five patients (82%) developed ischemic infarct while 12 patients (18%) had intracranial hemorrhagic. Pattern of ischemic infarct included global hypoxic injury in 30 patients (54.5%), posterior cerebral artery territory in 9 patients (16.3%), middle cerebral artery territory in 8 patients (14.5%), multiterritory involvement in 5 patients (9.0%), and anterior cerebral artery territory in 3 patients (5.4%). In patients with intracranial hemorrhage, 5 patients (7.4%) developed subarachnoid hemorrhage (SAH), 4 patients (5.9%) developed subdural hemorrhage, and 3 patients (4.4%) developed intraparenchymal hemorrhage. Conclusions: Neurological complication accounts for significant morbidity and mortality after congenital cardiac surgery. In our study, ischemic infarct accounted for 82% cases. In ischemic infarct, global ischemia was the most common type and carried high risk of mortality. In hemorrhage group, SAH was the most common finding. Nevertheless, the aim of this study was to characterize the current incidence of acute clinically evident neurologic complications in children undergoing congenital cardiac surgery in a tertiary hospital, although acute neurologic morbidity appears to be appreciably lower than in the past at our institution.

Duration of regional cerebral oxygen saturation under 40% is a risk factor for neurological injury following pulmonary thromboendarterectomy: A prospective observational study.

Deep hypothermic circulatory arrest (DHCA) is nowadays commonly used in pulmonary thromboendarterectomy (PTE). Neurological injury related to DHCA severely impairs the prognosis of patients. However, the risk factors and predictors of neurological injury are still unclear. We conducted a prospective observational study, including 82 patients diagnosed as chronic thromboembolic pulmonary hypertension and underwent PTE alone in our center from December 2016 to May 2021. Demographic characteristics, clinical and surgical data, and neurological adverse events were recorded prospectively. Univariate and multivariate analyses were conducted to identify the predictors of neurological injury. Eleven (13.4%) patients exhibited neurological injuries after surgery. Univariate analysis showed that the duration of regional cerebral oxygen saturation (rSO2 ) under 40% (p < .001), the minimum rSO2 (p = .006), and the percentage of decrease in rSO2 (p = .011) were significantly associated with neurological injury. Multivariate analysis showed that the duration of rSO2 under 40% was an independent predictor for postoperative neurological injury (odds ratio = 3.896, 95% confidence interval: 1.812-8.377, p < .001). The receiver operating characteristic curve showed that when the cut-off value was 1.25 min, its sensitivity for predicting neurological injury was 63.6% with a specificity of 88.7%. The duration of rSO2 under 40% is an independent predictor for neurological injury following PTE. For complicated lesions, more times of circulatory arrest were much safer and more reliable than a prolonged time of a single circulatory arrest. The circulation should be restored as soon as possible, when the rSO2 under 40% is detected, rather than waiting for 5 min.

Type A aortic dissection is more aggressive in women.

The aim of this study was to evaluate gender differences in the pre- and postoperative course in patients with acute aortic dissection type A. Of all patients undergoing surgery from 2000 to 2020, data on symptoms at presentation, operative strategy and postoperative course were analyzed. Long-term follow-up was obtained through visits at our outpatient clinic or via telephone interviews. Out of 394 patients, 32% (n = 126) were female. Women suffered from aortic dissection type A at an older age (women 67.5 years vs men 57 years; P > 0.001) and experienced a more aggressive preoperative course leading to critical presentation or even lethal rupture [women 7.9% (n = 10) vs men 2.2% (n = 6); P = 0.008]. Chest pain as initial symptom was more common in men [women 59.5% (n = 75) vs men 73.5% (n = 197); P = 0.005]. Perfusion of the right carotid was impaired more often [women 22.5% (n = 27) vs men 13.7% (n = 36); P = 0.031] and preoperative rate of neurological dysfunction was higher in women [women 23% (n = 29) vs men 14.2% (n = 38); P = 0.028]. Time from symptom onset to surgery did not differ between gender. Surgical repair was less extensive and faster in women. Female patients were more likely to suffer from postoperative neurological injury [women 23.8% (n = 30) vs men 10.2% (n = 40); P = 0.023]. We detected impaired 30-day and long-term survival in women. Women represent an older and sicker patient collective. Preoperative course of aortic dissection type A is more aggressive and complicated in women. While time from onset of symptoms to surgery did not differ between gender, neurological outcome and survival were impaired in women.

Cerebral Oximetry Measurements Results Depending on a Preclinical Skull Phantom Model

Abstract It is more common to perform non-invasive examination during general anaesthesia to ensure effective perioperative patient care. To achieve these results, researchers and clinicians are seeking out different technologies and developing new equipment. One such apparatus is a cerebral oximeter, which is used during cardiac surgery with cardiopulmonary bypass for neuroprotection management for reducing risk of postoperative neurological injury (cerebral stroke, neurocognitive dysfunction, and cerebral haemorrhage). A cerebral oximeter performs non-invasive transcutaneous measurements using near infrared radiation to assess the oxygenation of tissues. The objective of the study was to determine if the angle and thickness of a patient’s skull affects measurements. Intralipid water solution, gelatine, and ink were used to make six phantoms with skull thickness ranging from 6 to 11 mm. All phantoms were bent froma0to20 degrees angle. The cerebral oximeter SOMETICS INVOS 5100C was used to perform regional oximetry measurements. For skull thickness of 11 mm, the rSO2 was 45.8% (SD 0.96); for skull thickness of 10 mm, the rSO2 was 45.25% (SD 2.22); for skull thickness of 9 mm, the rSO2 was 32% (SD 1.63); for skull thickness of 8 mm, the rSO2 was 17% (SD 1.83); for skull thickness of 7 mm, the rSO2 was 15% (SD 0); for skull thickness of 6 mm, the rSO2 was 15% (SD 0). No significant changes were observed regarding the angle of the skull phantom. The thickness of the bone layer of the skull phantom affected the regional oximetry results, whereas the angle of the skull did not affect it.

Optical monitoring of cerebral perfusion and metabolism in adults during cardiac surgery with cardiopulmonary bypass.

During cardiac surgery with cardiopulmonary bypass (CPB), adequate maintenance of cerebral blood flow (CBF) is vital in preventing postoperative neurological injury - i.e. stroke, delirium, cognitive impairment. Reductions in CBF large enough to impact cerebral energy metabolism can lead to tissue damage and subsequent brain injury. Current methods for neuromonitoring during surgery are limited. This study presents the clinical translation of a hybrid optical neuromonitor for continuous intraoperative monitoring of cerebral perfusion and metabolism in ten patients undergoing non-emergent cardiac surgery with non-pulsatile CPB. The optical system combines broadband near-infrared spectroscopy (B-NIRS) to measure changes in the oxidation state of cytochrome c oxidase (oxCCO) - a direct marker of cellular energy metabolism - and diffuse correlation spectroscopy (DCS) to provide an index of cerebral blood flow (CBFi). As the heart was arrested and the CPB-pump started, increases in CBFi (88.5 ± 125.7%) and significant decreases in oxCCO (-0.5 ± 0.2 µM) were observed; no changes were noted during transitions off CPB. Fifteen hypoperfusion events, defined as large and sustained reductions in CPB-pump flow rate, were identified across all patients and resulted in significant decreases in perfusion and metabolism when mean arterial pressure dropped to 30 mmHg or below. The maximum reduction in cerebral blood flow preceded the corresponding metabolic reduction by 18.2 ± 15.0 s. Optical neuromonitoring provides a safe and non-invasive approach for assessing intraoperative perfusion and metabolism and has potential in guiding patient management to prevent adverse clinical outcomes.

Intraoperative hypotension and neurological outcomes.

Intraoperative hypotension (IOH) may render patients at a risk of cerebral hypoperfusion with decreasing cerebral blood flow (CBF), and lead to postoperative neurological injury. On the basis of the literature in recent years, this review attempts to refine the definition of IOH and evaluate its impact on neurological outcomes. Although both absolute and relative blood pressure (BP) thresholds, with or without a cumulative period, have been used in collective clinical studies, no definitive threshold of IOH has been established for neurological complications, including perioperative stroke, postoperative cognitive disorder and delirium. The CBF is jointly modulated by multiple pressure processes (i.e. cerebral pressure autoregulation) and nonpressure processes, including patient, surgical and anaesthesia-related confounding factors. The confounding factors and variability in cerebral pressure autoregulation might impede evaluating the effect of IOH on the neurological outcomes. Furthermore, the majority of the evidence presented in this review are cohort studies, which are weak in demonstrating a cause--effect relationship between IOH and neurological complications. The maintenance of target BP based on the monitoring of regional cerebral oxygen saturation (rScO2) or cerebral pressure autoregulation seems to be associated with the decreased incidence of postoperative neurological complications. Despite the lack of a known threshold value, IOH is a modifiable risk factor targeted to improve neurological outcomes. Ideal BP management is recommended in order to maintain target BP based on the monitoring of rScO2 or cerebral pressure autoregulation.

Analysis of modifiable and nonmodifiable risk factors in patients undergoing pituitary surgery.

Pituitary adenomas (PAs) are among the most common intracranial tumors. Understanding the clinical effects of various modifiable risk factors (MRFs) and nonmodifiable risk factors (NMRFs) is important in guiding proper treatment, yet there is limited evidence outlining the influence of MRFs and NMRFs on outcomes of PA resection. The aim of this study was to analyze MRFs and NMRFs in patients undergoing resection for PAs. Using the 2016 and 2017 National Readmission Database, the authors identified a cohort of 9472 patients undergoing microscopic or endoscopic resection of a PA. Patients with nonoverlapping MRFs and NMRFs were analyzed for length of stay (LOS), hospital cost, readmission rates, and postoperative complications. From the original cohort, a subset of 373 frail patients (as defined by the Johns Hopkins Frailty Index) were identified and propensity matched to nonfrail patients. Statistical analysis included 1-way ANOVA, Tukey multiple comparisons of means, odds ratios, Wald testing, and unpaired Welch 2-sample t-tests to compare complications, outcomes, and costs between each cohort. Perioperative outcomes and hospital readmission rates were tracked, and predictive algorithms were developed to establish precise relationships between relevant risk factors and neurosurgical outcomes. Malnourished patients had significantly longer LOSs when compared to nonmalnourished patients (p < 0.001). There was a significant positive correlation between the number of MRFs and readmission at 90 days (p = 0.012) and 180 days (p = 0.020). Obese patients had higher rates of postoperative neurological injury at the 30-day follow-up (p = 0.048) compared to patients with normal BMI. Within this NMRF cohort, frail patients were found to have significantly increased hospital LOS (p < 0.001) and total inpatient costs compared to nonfrail patients (p < 0.001). Predictive analytics showed that frail patients had significantly higher readmission rates at both 90-day (p < 0.001) and 180-day follow-ups (p < 0.001). Lastly, rates of acute postsurgical infection were higher in frail patients compared to nonfrail patients (p < 0.001). These findings suggest that both MRFs and NMRFs negatively affect the perioperative outcomes following PA resection. Notable risk factors including malnutrition, obesity, elevated lipid panels, and frailty make patients more prone to prolonged LOS, higher inpatient costs, and readmission. Further prospective research with longitudinal data is required to precisely pinpoint the effects of various risk factors on the outcomes of pituitary surgery.

Immediate Surgery in Acute Type A Dissection and Neurologic Dysfunction: Fighting the Inevitable?

Neurologic dysfunction remains an ongoing challenge in the diagnosis of type A aortic dissection (AAD). Our study analyzed the impact of preoperative neurologic dysfunction (PND) on outcome and assessed a potential link between PND and specific patterns of postoperative neurologic injury. Medical records of 338 patients (70.1% men; mean age, 59.3 ± 13.7 years) undergoing surgical repair for AAD were screened for the presence of PND. Preoperative characteristics, surgical treatment, and hospital and neurologic outcomes were analyzed according to patients with PND (PND+) and without PND (PND-) RESULTS: There were 50 patients (14.8%) admitted with PND. PND+ patients showed significantly higher rates of postoperative neurologic injury (44.4%) than PND- patients (14.3%; P < .001) with a specific pattern of ischemic lesions in accordance with preoperative neurologic status. While PND+ patients suffered mainly from right hemispheric strokes (66.7% vs 32.4% in PND- patients, P= .024), PND- patients more frequently presented with bilateral cerebral ischemia (56.8% vs 13.3% in PND+ patients, P= .004). Multivariable analysis identified presence of PND (odds ratio, 2.977; 95% confidence interval, 1.357-6.545) as an independent predictor for new postoperative neurologic injury. PND was associated with impaired survival (P= .005). This study identified an association of preoperative neurologic status and specific stroke patterns after surgical repair of AAD. Irrespective of timing of surgery and reperfusion strategies, preoperative neurologic dysfunction is strongly associated with impaired neurologic outcome.

Outcome of surgical untethering of tethered cord syndrome in adults due to spina bifida occulta

Background:. Children with spina bifida occulta require early surgery to prevent neurological deficits. The treatment of patients with a congenitally tethered cord who present in adulthood remains controversial.&#x0D; Objective: The aim of this study is to describe the outcome obtained in 61 adult patients with congenital TCS and no prior surgical treatment who underwent surgical untethering.&#x0D; Methods: This prospective study was conducted on 61 adult patients who underwent surgical untethering for spina bifida occulta at four neurosurgical centers in Baghdad / Iraq between March 2000 and January 2018. Patients who had undergone prior myelomeningocele repair or tethered cord release surgery were excluded.&#x0D; The most common intraoperative findings were lipomyelomeningocele (41%) and a tight terminal filum (36%). The follow-up duration ranged from 10.8 to 149.5 months (mean 20.9 months). Of the 34 patients with back pain, status improved in 65%, worsened in 3%, remained unchanged in 18%, and improved and later recurred in 15%. Lower-extremity pain improved in 16 patients (53%), remained unchanged in 23%, improved and then recurred in 17%, and worsened in 7%. Lower-extremity weakness improved in 47%, remained unchanged in 47%, and improved and then recurred in 5%. Finally, of the 17 patients with lower-extremity sensory changes,&#x0D; status improved in 35%, remained unchanged in 35%, and the information on five patients was unavailable. Surgical complications included three wound infections, one cerebrospinal fluid leak, and two pseudomeningoceles requiring surgical revision. One patient developed acute respiratory distress syndrome and sepsis postoperatively and died several days later.&#x0D; Conclusions: Adult-age presentation of a congenital tethered cord is unusual. Despite a slight increase in postoperative neurological injury in adults, surgery has relatively low risk and offers good potential for neurological improvement or stabilization. As in children, we recommend early surgery in adults with this disorder. The decision to undertake surgery, however, should be modulated by other factors such as a patient’s general medical condition and risk posed by anesthesia.

Skull Clamp Application: A Safe, Team-based Approach and Literature Review

Outcomes in posterior cervical spine surgery are highly dependent on proper operative head and neck positioning. As with any spinal procedure, posterior cervical surgery can be associated with significant morbidity; known complications directly related to positioning include postoperative vision loss, neurological injury, and poor surgical outcome. Unsurprisingly, a variety of techniques have been developed that aim to mitigate these complications while improving overall outcomes. The aim of this article is to present a standardized technique for application of the Mayfield skull clamp focusing on a team-based approach for patient positioning to minimize complications. The existing literature is also reviewed for complications associated with head positioning devices. Our method of clamp application and patient positioning minimizes complications (0.36% over a 14-y period), optimizes surgical exposure with anatomic position of the bony elements, and maximizes intraoperative spinal stability. This protocol is ideal for all the posterior cervical procedures.

Non-invasive optical neuromonitoring of the temperature-dependence of cerebral oxygen metabolism during deep hypothermic cardiopulmonary bypass in neonatal swine

Management of deep hypothermic (DH) cardiopulmonary bypass (CPB), a critical neuroprotective strategy, currently relies on non-invasive temperature to guide cerebral metabolic suppression during complex cardiac surgery in neonates. Considerable inter-subject variability in temperature response and residual metabolism may contribute to the persisting risk for postoperative neurological injury. To characterize and mitigate this variability, we assess the sufficiency of conventional nasopharyngeal temperature (NPT) guidance, and in the process, validate combined non-invasive frequency-domain diffuse optical spectroscopy (FD-DOS) and diffuse correlation spectroscopy (DCS) for direct measurement of cerebral metabolic rate of oxygen (CMRO2). During CPB, n = 8 neonatal swine underwent cooling from normothermia to 18℃, sustained DH perfusion for 40 min, and then rewarming to simulate cardiac surgery. Continuous non-invasive and invasive measurements of intracranial temperature (ICT) and CMRO2 were acquired. Significant hysteresis (p < 0.001) between cooling and rewarming periods in the NPT versus ICT and NPT versus CMRO2 relationships were found. Resolution of this hysteresis in the ICT versus CMRO2 relationship identified a crucial insufficiency of conventional NPT guidance. Non-invasive CMRO2 temperature coefficients with respect to NPT (Q10 = 2.0) and ICT (Q10 = 2.5) are consistent with previous reports and provide further validation of FD-DOS/DCS CMRO2 monitoring during DH CPB to optimize management.

Editor's Choice – Current Options and Recommendations for the Treatment of Thoracic Aortic Pathologies Involving the Aortic Arch: An Expert Consensus Document of the European Association for Cardio-Thoracic Surgery (EACTS) & the European Society for Vascular Surgery (ESVS)

Editor's Choice – Current Options and Recommendations for the Treatment of Thoracic Aortic Pathologies Involving the Aortic Arch: An Expert Consensus Document of the European Association for Cardio-Thoracic Surgery (EACTS) & the European Society for Vascular Surgery (ESVS)

Avoiding Neurological Complications of Elbow Arthroscopy

Elbow arthroscopy is an increasingly common procedure performed in orthopaedic surgery. However, because of the presence of several major neurovascular structures in close proximity to the operative portals, it can have potentially devastating complications. The largest series of elbow arthroscopies to date described a 2.5% rate of postoperative neurological injury. All of these injuries were transient nerve injuries resolved without intervention. A recent report of major nerve injuries after elbow arthroscopy demonstrated that these injuries are likely under-reported in literature. Because of the surrounding neurovascular structures, familiarity with normal elbow anatomy and portals will decrease the risk of damaging important structures. The purpose of this Technical Note is to review important steps in performing elbow arthroscopy with an emphasis on avoiding neurovascular injury. With a sound understanding of the important bony anatomic landmarks, sensory nerves, and neurovascular structures, elbow arthroscopy can provide both diagnostic and therapeutic intervention with little morbidity.

T139. The utility of Intraoperative Neurophysiologic Monitoring (IONM) in latarjet procedures

Introduction The Latarjet procedure is a surgical treatment option in treatment of shoulder instability and can be associated with up to 10% risk of a new postoperative neurologic injury. The utility of IONM during the Latarjet procedure is previously demonstrated in one study that assessed the relative risks of distinct surgical steps ( Delaney, 2014 ). However, the spectrum of neurophysiologic changes remains undefined. In this study, we reviewed the pattern of changes, sensitivity and specificity of IONM in detection of a new postoperative neurologic deficit. Methods A retrospective chart review was performed in our prospectively collected database to identify patients undergoing Latarjet procedure with utilization of IONM. A total of 14 Latarjet procedures was performed in 12 patients with a median age of 37, between August 2013 and April 2017. We reviewed demographic information, intraoperative details including neurophysiologic monitoring and clinical follow up data postoperatively at 2 weeks and 6 weeks. Results Out of the 14 latarjet procedures, neurophysiologic changes were encountered in 6 procedures and included changes only in the transcranial motor evoked potentials (tcMEPs). There were no changes in somatosensory evoked potentials (SSEP) after ipsilateral median or ulnar nerve stimulation. The tcMEP changes were persistent in 4 procedures and transient in the remaining two procedures. No patient without an intraoperative alert or a transient tcMEP change experienced a new postoperative deficit. Out of the four patients with persistent tcMEP changes, three patients experienced new sensory and motor postoperative deficits in the axillary nerve distribution at 2-week follow-up. One patient continued to experience persistent motor and sensory deficits at 6 week follow up and the remaining two patients demonstrated significant clinical improvement with only residual sensory symptoms. The IONM overall demonstrated 100% sensitivity and 90.9% specificity for a persistent tcMEP change in detecting a new postoperative neurologic deficit. Conclusion This review demonstrates the utility of tcMEPs in predicting intraoperative axillary nerve injury and related postoperative neurologic deficits. Sampling of the deltoid muscle in anterior, middle and posterior compartments increased the sensitivity for detection of an axillary nerve injury. This review also highlights a need for revision of the SSEP monitoring protocol as the postoperative neurologic deficits in the axillary nerve were not detected with median or ulnar nerve stimulation.

Cerebral Function and Perfusion during Cardiopulmonary Bypass: A Plea for a Multimodal Monitoring Approach.

Postoperative neurological injury still represents a major cause of morbidity after cardiac surgery. Our objective was to compare the limits as well as advantages of routine monitoring tools for the detection of cerebral function and perfusion deficits during cardiopulmonary bypass in a daily clinical setting. Adult patients undergoing elective cardiac surgery with use of cardiopulmonary bypass were included. Patients received monitoring comprising Bispectral Index (BIS), Near Infrared Spectroscopy (NIRS) and assessment of middle cerebral artery flow velocity (MCAV) using transcranial Doppler (TCD) sonography. Measurements were taken after anesthesia induction (at baseline) and every 10 minutes during aortic cross-clamping. Relative deviation from baseline values was calculated. Values were compared with predefined, generally accepted threshold values identifying patients at risk for cerebral functional and perfusion deficits. 30 consecutive patients were included into data analysis. Compared to NIRS as well as BIS monitoring, there was a wide interindividual variability in relative MCAV values for the whole cohort (median 0.9, range 0.39-2.19). Out of 229 measurements in total, 82 BIS but only 30 NIRS and 12 TCD values were lying outside predefined limits. TCD monitoring identified two patients with disturbed cerebral autoregulation, while NIRS remained unremarkable. The latter was significantly associated with systemic hemoglobin levels. Finally, patients with relative MCAV values >1.0 had a higher risk of developing postoperative delirium. Our findings reveal inherent technical limitations of each individual monitoring component, such as high interindividual variability (TCD), low spatial resolution (NIRS), or interaction with anesthetics (BIS). We therefore argue for a multimodal neuromonitoring that combines several qualities. Such approach would help reducing these limitations while individual components complement each other, thus providing more patient safety during cardiac surgery. Furthermore, such an approach would be easily applicable in a routine clinical setting.

Cerebral near-infrared spectroscopy (NIRS) for perioperative monitoring of brain oxygenation in children and adults.

Cerebral near-infrared spectroscopy (NIRS) for perioperative monitoring of brain oxygenation in children and adults.

Minimally Invasive Implantation of HeartWare Assist Device and Simultaneous Tricuspid Valve Reconstruction Through Partial Upper Sternotomy.

Left ventricular assist device (LVAD) implantation is a well-established therapy to support patients with end-stage heart failure. However, the operative procedure is associated with severe trauma. Third generation LVADs like the HeartWare assist device (HeartWare, Inc., Framingham, MA, USA) are characterized by enhanced technology despite smaller size. These devices offer new minimally invasive surgical options. Tricuspid regurgitation requiring valve repair is frequent in patients with the need for mechanical circulatory support as it is strongly associated with ischemic and nonischemic cardiomyopathy. We report on HeartWare LVAD implantation and simultaneous tricuspid valve reconstruction through minimally invasive access by partial upper sternotomy to the fifth left intercostal space. Four male patients (mean age 51.72 ± 11.95 years) suffering from chronic heart failure due to dilative (three patients) and ischemic (one patient) cardiomyopathy and also exhibiting concomitant tricuspid valve insufficiency due to annular dilation underwent VAD implantation and tricuspid valve annuloplasty. Extracorporeal circulation was established via the ascending aorta, superior vena cava, and right atrium. In all four cases the LVAD implantation and tricuspid valve repair via partial median sternotomy was successful. During the operative procedure, no conversion to full sternotomy was necessary. One patient needed postoperative re-exploration because of pericardial effusion. No postoperative focal neurologic injury was observed. New generation VADs are advantageous because of the possibility of minimally invasive implantation procedure which can therefore minimize surgical trauma. Concomitant tricuspid valve reconstruction can also be performed simultaneously through partial upper sternotomy. Nevertheless, minimally invasive LVAD implantation is a challenging operative technique.

An Observational Study of Cerebral Blood Flow Velocity During Hypotensive Epidural Anesthesia.

Hypotensive epidural anesthesia (HEA), as practiced at our institution, uses sympathetic blockade to achieve mean arterial blood pressure (MAP) of ≤50 mm Hg while administering epinephrine by infusion to support the circulation. HEA has not been associated with gross adverse effects on neurologic outcome or cognitive function in the postoperative period, suggesting adequate cerebral blood flow (CBF). However, the use of MAPs well below the commonly accepted lower limit of CBF autoregulation suggests that CBF should be significantly reduced below normal levels. To examine these conflicting hypotheses, we performed a prospective investigation of the effects of HEA on CBF velocity (CBFV), an accepted index of cerebral perfusion. Fifty-two hip replacement patients were studied. HEA was induced by lumbar epidural injection of local anesthetic and infusion of epinephrine to achieve an MAP of ≤50 mm Hg. Propofol/midazolam sedation was administered. Baseline CBFV was recorded pre-HEA (after sedation and before local anesthetic injection) and continuously thereafter. During HEA, MAP decreased by 40% and was stable throughout. The CBFVmean at baseline and at 3 HEA intervals during surgery was 46 ± 12 (SD), 45 ± 12, 47 ± 14, and 47 ± 14 cm·s, respectively. Although mean CBFVmean did not vary, there was considerable heterogeneity among patients. Twelve patients (23%) experienced reductions of CBFVmean of >20% during HEA intervals (99% lower confidence limit: 9%) and 6 (12%) reductions of >30% (99% lower confidence limit: 1%). There was no correlation between CBFVmean and MAP for MAPs between 100 and 40 mm Hg (R = 0.0015, P = 0.44). There were no instances of gross postoperative neurologic injury. Both hypotheses proved partially correct. CBFV was sometimes well maintained during HEA, despite MAPs well below the commonly accepted lower limit of autoregulation. However, there was considerable interindividual heterogeneity with 23% of subjects having CBFV reductions >20% (99% lower confidence limit: 9%), with some reductions approaching the threshold for ischemic injury. The present data do not allow us to determine whether hypotension would be similarly tolerated in other circumstances.