Joanna L. Mergeche

Factors that correlate with the decision to delay extubation after multilevel prone spine surgery.

Background: Multilevel spinal decompressions and fusions often require long anesthetic and operative times, which may result in airway edema and prolonged postoperative intubation. Delayed extubation can lead to bronchopulmonary infections and other complications. This study analyzed which factors correlated with the decision to delay extubation after multilevel spine surgery. Methods: We reviewed the records of 289 patients who underwent multilevel spine surgery lasting ≥8 hours in the prone position from 2006 to 2012. Variables hypothesized to affect the decision of the anesthesiologist to delay extubation at the end of the surgery were collected. These included preoperative factors (age, sex, ASA class, history of obstructive sleep apnea, BMI, previous spine surgery, current cervical surgery, anterior in addition to posterior spine surgery, emergency surgery) and intraoperative factors (difficult intubation, number of surgical levels, case time, estimated blood loss, fluid and blood administration, attending handoff and resident handoff, and case end time). We also compared the incidence of pulmonary postoperative complications between patients extubated at the end of the case to patients who had a delayed extubation. Results: A total of 126 patients (44%) were kept intubated after multilevel spine surgery. Multiple linear regression analysis showed factors that correlated with prolonged intubation which included age, ASA class, procedure duration, extent of surgery, total crystalloid volume administered, total blood volume administered, and the case end time. Patients who had a delayed extubation had a 3-fold higher rate of postoperative pneumonia. Conclusions: Our study found that age, ASA class, procedure duration, extent of surgery, and total crystalloid and blood volume administered correlate with the decision to delay extubation in multilevel prone spine surgery. It also finds that the time the case ends is an independent variable that correlates with the decision not to extubate at the end of a long multilevel spinal surgery. The incidence of postoperative pneumonia is higher in patients who had a delayed extubation after surgery.

Arterial Blood Pressure Management During Carotid Endarterectomy and Early Cognitive Dysfunction

BACKGROUND A common practice during cross-clamp of carotid endarterectomy (CEA) is to manage mean arterial pressure (MAP) above baseline to optimize the collateral cerebral blood flow and reduce the risk of ischemic stroke. OBJECTIVE To determine whether MAP management ≥20% above baseline during cross-clamp is associated with lower risk of early cognitive dysfunction, a subtler form of neurological injury than stroke. METHODS One hundred eighty-three patients undergoing CEA were enrolled in this ad hoc study. All patients had radial arterial catheters placed before the induction of general anesthesia. MAP was managed at the discretion of the anesthesiologist. All patients were evaluated with a battery of neuropsychometric tests preoperatively and 24 hours postoperatively. RESULTS Overall, 28.4% of CEA patients exhibited early cognitive dysfunction (eCD). Significantly fewer patients with MAP ≥20% above baseline during cross-clamp exhibited eCD than those managed <20% above (11.6% vs 38.6%, P < .001). In a multivariate logistic regression model, MAP ≥20% above baseline during the cross-clamp period was associated with significantly lower risk of eCD (odds ratio [OR], 0.18 [0.07-0.40], P < .001), whereas diabetes mellitus (OR, 2.73 [1.14-6.61], P = .03) and each additional year of education (OR, 1.19 [1.06-1.34], P = .003) were associated with significantly higher risk of eCD. CONCLUSION The observations of this study suggest that MAP management ≥20% above baseline during cross-clamp of the carotid artery may be associated with lower risk of eCD after CEA. More prospective work is necessary to determine whether MAP ≥20% above baseline during cross-clamp can improve the safety of this commonly performed procedure.

Neutrophil-lymphocyte ratio as a predictor of cognitive dysfunction in carotid endarterectomy patients

BACKGROUND Systemic inflammation has been implicated in the development of cognitive dysfunction following carotid endarterectomy (CEA). Neutrophil-lymphocyte ratio (NLR) is a reliable measure of systemic inflammation. We hypothesize that patients with elevated preoperative NLR have increased risk of cognitive dysfunction 1 day after CEA. METHODS Five hundred fifty-one patients scheduled for CEA were enrolled at Columbia University in New York, NY from 1995 to 2012. NLR was retrospectively reviewed; only 432 patients had preoperative NLR values available within 2 weeks of CEA. NLR was analyzed as a continuous variable and categorically with a cutoff of ≥5 and <5 and equal tertiles, as done in previous studies. RESULTS Patients with cognitive dysfunction had significantly higher NLR than those without cognitive dysfunction (4.5 ± 4.0 vs 3.2 ± 2.6; P < .001). The incidence of cognitive dysfunction was significantly higher in patients with NLR ≥5 than NLR <5 (34.7% vs 12.8%; P < .001). Significantly fewer patients in the low tertile had cognitive dysfunction than in the high tertile (6.9% vs 25.9%; P <.001) and middle tertile (6.9% vs 17.4%; P = .006). In the final multivariate model, diabetes mellitus (odds ratio [OR], 2.03; 95% confidence interval [CI], 1.08-3.75; P = .03) and NLR ≥5 (OR, 3.38; 95% CI, 1.81-6.27; P < .001) were significantly associated with higher odds of cognitive dysfunction, while statin use was significantly associated with lower odds (OR, 0.48; 95% CI, 0.27-0.84; P = .01). CONCLUSIONS Preoperative NLR is associated with cognitive dysfunction 1 day after CEA. NLR ≥5 and diabetes mellitus are significantly associated with increased odds of cognitive dysfunction whereas statin use is significantly associated with decreased odds.

Inflammation and Cognitive Dysfunction in Type 2 Diabetic Carotid Endarterectomy Patients

OBJECTIVE Type 2 diabetic patients have a high incidence of cerebrovascular disease, elevated inflammation, and high risk of developing cognitive dysfunction following carotid endarterectomy (CEA). To elucidate the relationship between inflammation and the risk of cognitive dysfunction in type 2 diabetic patients, we aim to determine whether elevated levels of systemic inflammatory markers are associated with cognitive dysfunction 1 day after CEA. RESEARCH DESIGN AND METHODS One hundred fifteen type 2 diabetic CEA patients and 156 reference surgical patients were recruited with written informed consent in this single-center cohort study. All patients were evaluated with an extensive battery of neuropsychometric tests. Preoperative monocyte counts, HbA1c, C-reactive protein (CRP), intercellular adhesion molecule 1, and matrix metalloproteinase 9 activity levels were obtained. RESULTS In a multivariate logistic regression model constructed to identify predictors of cognitive dysfunction in type 2 diabetic CEA patients, each unit of monocyte counts (odds ratio [OR] 1.76 [95% CI 1.17–2.93]; P = 0.005) and CRP (OR 1.17 [1.10–1.29]; P < 0.001) was significantly associated with higher odds of developing cognitive dysfunction 1 day after CEA in type 2 diabetic patients. CONCLUSIONS Type 2 diabetic patients with elevated levels of preoperative systemic inflammatory markers exhibit more cognitive dysfunction 1 day after CEA. These observations have implications for the preoperative medical management of this high-risk group of surgical patients undergoing carotid revascularization with CEA.

Impact of Cognitive Dysfunction on Survival in Patients With and Without Statin Use Following Carotid Endarterectomy.

BACKGROUND Early cognitive dysfunction (eCD) is a subtle form of neurological injury observed in ∼25% of carotid endarterectomy (CEA) patients. Statin use is associated with a lower incidence of eCD in asymptomatic patients having CEA. OBJECTIVE To determine whether eCD status is associated with worse long-term survival in patients taking and not taking statins. METHODS This is a post hoc analysis of a prospective observational study of 585 CEA patients. Patients were evaluated with a battery of neuropsychometric tests before and after surgery. Survival was compared for patients with and without eCD stratifying by statin use. At enrollment, 366 patients were on statins and 219 were not. Survival was assessed by using Kaplan-Meier methods and multivariable Cox proportional hazards models. RESULTS Age ≥75 years (P = .003), diabetes mellitus (P < .001), cardiac disease (P = .02), and statin use (P = .014) are significantly associated with survival univariately (P < .05) by use of the log-rank test. By Cox proportional hazards model, eCD status and survival adjusting for univariate factors within statin and nonstatin use groups suggested a significant effect by association of eCD on survival within patients not taking statin (hazard ratio, 1.61; 95% confidence interval, 1.09-2.40; P = .018), and no significant effect of eCD on survival within patients taking statin (hazard ratio, 0.98; 95% confidence interval, 0.59-1.66; P = .95). CONCLUSION eCD is associated with shorter survival in patients not taking statins. This finding validates eCD as an important neurological outcome and suggests that eCD is a surrogate measure for overall health, comorbidity, and vulnerability to neurological insult. ABBREVIATIONS aHR, adjusted hazards ratiosCEA, carotid endarterectomyCI, confidence intervalDM, diabetes mellituseCD, early cognitive dysfunctionNDI, National Death IndexNLR, neutrophil/lymphocyte ratioSD, standard deviationSEM, standard error of the mean.

Middle cerebral artery pulsatility index and cognitive improvement after carotid endarterectomy for symptomatic stenosis.

OBJECT Transcranial Doppler (TCD) is frequently used to evaluate peripheral cerebral resistance and cerebral blood flow (CBF) in the middle cerebral artery prior to and during carotid endarterectomy (CEA). Patients with symptomatic carotid artery stenosis may have reduced peripheral cerebral resistance to compensate for inadequate CBF. The authors aim to determine whether symptomatic patients with reduced peripheral cerebral resistance prior to CEA demonstrate increased CBF and cognitive improvement as early as 1 day after CEA. METHODS Fifty-three patients with symptomatic CEA were included in this observational study. All patients underwent neuropsychometric evaluation 24 hours or less preoperatively and 1 day postoperatively. The MCA was evaluated using TCD for CBF mean velocity (MV) and pulsatility index (PI). Pulsatility index ≤ 0.80 was used as a cutoff for reduced peripheral cerebral resistance. RESULTS Significantly more patients with baseline PI ≤ 0.80 exhibited cognitive improvement 1 day after CEA than those with PI > 0.80 (35.0% vs 6.1%, p = 0.007). Patients with cognitive improvement had a significantly greater increase in CBF MV than patients without cognitive improvement (13.4 ± 17.1 cm/sec vs 4.3 ± 9.9 cm/sec, p = 0.03). In multivariate regression model, a baseline PI ≤ 0.80 was significantly associated with increased odds of cognitive improvement (OR 7.32 [1.40-59.49], p = 0.02). CONCLUSIONS Symptomatic CEA patients with reduced peripheral cerebral resistance, measured as PI ≤ 0.80, are likely to have increased CBF and improved cognitive performance as early as 1 day after CEA for symptomatic carotid artery stenosis. Revascularization in this cohort may afford benefits beyond prevention of future stroke. Clinical trial registration no: NCT00597883 ( ClinicalTrials.gov ).

Reduced middle cerebral artery velocity during cross-clamp predicts cognitive dysfunction after carotid endarterectomy

Transcranial Doppler (TCD) is a useful monitor that can be utilized during carotid endarterectomy (CEA). Cognitive dysfunction is a subtler and more common form of neurologic injury than stroke. We aimed to determine whether reduced middle cerebral artery (MCA) mean velocity (MV) predicts cognitive dysfunction and if so, whether a threshold of increased risk of cognitive dysfunction can be identified. One hundred twenty-four CEA patients were included in this observational study and neuropsychometrically evaluated preoperatively and 24 hours postoperatively. MCA-MV was measured by TCD and percentage of baseline during cross-clamp was calculated (MV(cross-clamp)/MV(baseline)). Patients with cognitive dysfunction had significantly lower MV during cross-clamp than those without cognitive dysfunction (33.1 ± 13.7 cm/s versus 39.6 ± 16.0 cm/s, p=0.02). In the final multivariate model, each percent reduction in MV was significantly associated with greater risk of cognitive dysfunction (odds ratio [OR]: 0.05 [95% confidence interval {CI} 0.01-0.23], p < 0.001) while statin use was associated with lower risk (OR: 0.33 [95% CI 0.12-0.92], p = 0.03). Using receiver operator characteristic curve analysis, the Youden index identified 72% of baseline MV during cross-clamp as the cutoff of maximum discrimination. Significantly more patients with MV < 72% of baseline during cross-clamp exhibited cognitive dysfunction than patients with MV ≥ 72% of baseline (74.1% versus 27.1%, p < 0.001). Reduced MCA-MV during cross-clamp is a predictor of cognitive dysfunction exhibited 24 hours after CEA. MCA-MV reduced to <72% of baseline, or a ≥28% reduction from baseline, is the threshold most strongly associated with increased risk of cognitive dysfunction. These observations should be considered by all clinicians that utilize intraoperative monitoring for CEA.

Phosphodiesterase 4D Single-Nucleotide Polymorphism 83 and Cognitive Dysfunction in Carotid Endarterectomy Patients

BACKGROUND Phosphodiesterase 4D (PDE4D), through the regulation of cyclic AMP, modulates inflammation and other processes that affect atherosclerosis and stroke. A PDE4D polymorphism, single-nucleotide polymorphism (SNP) 83 (rs966221), is associated with ischemic stroke. The association of SNP 83 with postoperative cognitive dysfunction has never been investigated. OBJECTIVE To determine whether SNP 83 is associated with cognitive dysfunction 1 day and 1 month following carotid endarterectomy (CEA). METHODS Three hundred fourteen patients with high-grade carotid stenosis scheduled for CEA consented to participate in this single-center cohort study of cognitive dysfunction. RESULTS Patients with the C/C genotype of SNP 83 exhibited significantly more cognitive dysfunction at 1 day (29.7%) than the C/T (15.8%, P = .008) and T/T (12.7%, P = .01) genotypes. In a multivariate logistic regression model, C/T and T/T genotypes were both associated with significantly decreased odds of cognitive dysfunction compared with the C/C genotype (odds ratio, 0.45 [0.24-0.83], P = .01 and odds ratio, 0.33 [0.12-0.77], P = .02). There were no significant associations at 1 month. CONCLUSION The C/C genotype of SNP 83 is significantly associated with the highest incidence of cognitive dysfunction 1 day following CEA in comparison with the C/T and T/T genotypes. This PDE4D genotype may lead to accelerated cyclic AMP degradation and subsequently elevated inflammation 1 day after CEA. These observations, in conjunction with previous studies, suggest that elevated inflammatory states may be partially responsible for the development of cognitive dysfunction after CEA, but more investigation is required.

Radiographic absence of the posterior communicating arteries and the prediction of cognitive dysfunction after carotid endarterectomy

OBJECT Approximately 25% of patients exhibit cognitive dysfunction 24 hours after carotid endarterectomy (CEA). One of the purported mechanisms of early cognitive dysfunction (eCD) is hypoperfusion due to inadequate collateral circulation during cross-clamping of the carotid artery. The authors assessed whether poor collateral circulation within the circle of Willis, as determined by preoperative CT angiography (CTA) or MR angiography (MRA), could predict eCD. METHODS Patients who underwent CEA after preoperative MRA or CTA imaging and full neuropsychometric evaluation were included in this study (n = 42); 4 patients were excluded due to intraoperative electroencephalographic changes and subsequent shunt placement. Thirty-eight patients were included in the statistical analyses. Patients were stratified according to posterior communicating artery (PCoA) status (radiographic visualization of at least 1 PCoA vs of no PCoAs). Variables with p < 0.20 in univariate analyses were included in a stepwise multivariate logistic regression model to identify predictors of eCD after CEA. RESULTS Overall, 23.7% of patients exhibited eCD. In the final multivariate logistic regression model, radiographic absence of both PCoAs was the only independent predictor of eCD (OR 9.64, 95% CI 1.43-64.92, p = 0.02). CONCLUSIONS The absence of both PCoAs on preoperative radiographic imaging is predictive of eCD after CEA. This finding supports the evidence for an underlying ischemic etiology of eCD. Larger studies are justified to verify the findings of this study. Clinical trial registration no.: NCT00597883 ( http://www.clinicaltrials.gov ).

Complement polymorphisms and cognitive dysfunction after carotid endarterectomy

OBJECT The role of genetic polymorphisms in the neurological outcome of patients after carotid endarterectomy (CEA) remains unclear. There are single nucleotide polymorphisms (SNPs) that predispose patients to postoperative cognitive dysfunction (CD). We aim to assess the predictability of three complement cascade-related SNPs for CD in patients having CEAs. METHODS In 252 patients undergoing CEA, genotyping was performed for the following polymorphisms: complement component 5 (C5) rs17611, mannose-binding lectin 2 (MBL2) rs7096206, and complement factor H (CFH) rs1061170. Differences among genotypes were analyzed via the chi-square test. Patients were evaluated with a neuropsychometric battery for CD 1 day and 1 month after CEA. A multiple logistic regression model was created. All variables with univariate p < 0.20 were included in the final model. RESULTS The C5 genotypes A/G (OR 0.26, 95% CI 0.11-0.60, p = 0.002) and G/G (OR 0.22, 95% CI 0.09-0.52, p < 0.001) were significantly associated with lower odds of exhibiting CD at 1 day after CEA compared with A/A. The CFH genotypes C/T (OR 3.37, 95% CI 1.69-6.92, p < 0.001) and C/C (OR 3.67, 95% CI 1.30-10.06, p = 0.012) were significantly associated with higher odds of exhibiting CD at 1 day after CEA compared with T/T. Statin use was also significantly associated with lower odds of exhibiting CD at 1 day after CEA (OR 0.43, 95% CI 0.22-0.84, p = 0.01). No SNPs were significantly associated with CD at 1 month after CEA. CONCLUSIONS The presence of a deleterious allele in the C5 and CFH SNPs may predispose patients to exhibit CD after CEA. This finding supports previous data demonstrating that the complement cascade system may play an important role in the development of CD. These findings warrant further investigation.