Mediators and moderators of change in mindfulness-based stress reduction for painful diabetic peripheral neuropathy.

Painful diabetic peripheral neuropathy (PDPN) is a chronic pain condition with modest response to pharmacotherapy. Participation in mindfulness-based stress reduction (MBSR) leads to improvements in pain-related outcomes but the mechanisms of change are unknown. The present study examined the mediators and moderators of change in 62 patients with PDPN who participated in a randomized controlled trial comparing MBSR to waitlist. Changes in mindfulness and pain catastrophizing were tested simultaneously as mediators. Increased mindfulness mediated the association between participation in MBSR and improved pain severity, pain interference, and the physical component of health-related quality of life (HRQoL) 3 months later. The mediation effect of pain catastrophizing was not significant. Linear moderated trends were also found. Post-hoc moderated mediation analyses suggested that MBSR patients with longer histories of diabetes might increase their mindfulness levels more, which in turn leads to improved pain severity and physical HRQoL. These results allow for a deeper understanding of pathways by which MBSR benefits patients with PDPN.

Sensitivity of the DN4 in Screening for Neuropathic Pain Syndromes.

OBJECTIVES: Several tools have been developed to screen for neuropathic pain. This study examined the sensitivity of the Douleur Neuropathique en 4 Questions (DN4) in screening for various neuropathic pain syndromes. MATERIALS AND METHODS: This prospective observational study was conducted in 7 Canadian academic pain centers between April 2008 and December 2011. All newly admitted patients (n=2199) were approached and 789 eligible participants form the sample for this analysis. Baseline data included demographics, disability, health-related quality of life, and pain characteristics. Diagnosis of probable or definite neuropathic pain was on the basis of history, neurological examination, and ancillary diagnostic tests. RESULTS: The mean age of study participants was 53.5 years and 54.7% were female; 83% (n=652/789) screened positive on the DN4 (≥4/10). The sensitivity was highest for central neuropathic pain (92.5%, n=74/80) and generalized polyneuropathies (92.1%, n=139/151), and lowest for trigeminal neuralgia (69.2%, n=36/52). After controlling for confounders, the sensitivity of the DN4 remained significantly higher for individuals with generalized polyneuropathies (odds ratio [OR]=4.35; 95% confidence interval [CI]: 2.15, 8.81), central neuropathic pain (OR=3.76; 95% CI: 1.56, 9.07), and multifocal polyneuropathies (OR=1.72; 95% CI: 1.03, 2.85) compared with focal neuropathies. DISCUSSION: The DN4 performed well; however, sensitivity varied by syndrome and the lowest sensitivity was found for trigeminal neuralgia. A positive DN4 was associated with greater pain catastrophizing, disability and anxiety/depression, which may be because of disease severity, and/or these scales may reflect magnification of sensory symptoms and findings. Future research should examine how the DN4 could be refined to improve its sensitivity for specific neuropathic pain conditions.

Randomized Trial of the Effect of Mindfulness-Based Stress Reduction on Pain-Related Disability, Pain Intensity, Health-Related Quality of Life, and A1C in Patients With Painful Diabetic Peripheral Neuropathy.

IN BRIEF Painful diabetic peripheral neuropathy (PDPN) has a large negative impact on patients' physical and mental functioning, and pharmacological therapies rarely provide more than partial relief. Mindfulness-based stress reduction (MBSR) is a group psychosocial intervention that was developed for patients with chronic illness who were not responding to existing medical treatments. This study tested the effects of community-based MBSR courses for patients with PDPN. Among patients whose PDPN pharmacotherapy had been optimized in a chronic pain clinic, those randomly assigned to treatment with MBSR experienced improved function, better health-related quality of life, and reduced pain intensity, pain catastrophizing, and depression compared to those receiving usual care.

The relationship between mindfulness, pain intensity, pain catastrophizing, depression, and quality of life among cancer survivors living with chronic neuropathic pain.

PURPOSE: This study aims to examine if mindfulness is associated with pain catastrophizing, depression, disability, and health-related quality of life (HRQOL) in cancer survivors with chronic neuropathic pain (CNP). METHOD: We conducted a cross-sectional survey with cancer survivors experiencing CNP. Participants (n = 76) were men (24 %) and women (76 %) with an average age of 56.5 years (SD = 9.4). Participants were at least 1 year post-treatment, with no evidence of cancer, and with symptoms of neuropathic pain for more than three months. Participants completed the Five Facets Mindfulness Questionnaire (FFMQ), along with measures of pain intensity, pain catastrophizing, pain interference, depression, and HRQOL. RESULTS: Mindfulness was negatively correlated with pain intensity, pain catastrophizing, pain interference, and depression, and it was positively correlated with mental health-related HRQOL. Regression analyses demonstrated that mindfulness was a negative predictor of pain intensity and depression and a positive predictor of mental HRQOL after controlling for pain catastrophizing, age, and gender. The two mindfulness facets that were most consistently associated with better outcomes were non-judging and acting with awareness. Mindfulness significantly moderated the relationships between pain intensity and pain catastrophizing and between pain intensity and pain interference. CONCLUSION: It appears that mindfulness mitigates the impact of pain experiences in cancer survivors experiencing CNP post-treatment. IMPLICATIONS FOR CANCER SURVIVORS: This study suggests that mindfulness is associated with better adjustment to CNP. This provides the foundation to explore whether mindfulness-based interventions improve quality of life among cancer survivors living with CNP.

Opioid use among same-day surgery patients: Prevalence, management and outcomes.

OBJECTIVES: To determine whether the prevalence of opioid use among patients requiring elective same-day admission (SDA) surgery is greater than the 2.5% prevalence found in the general population. Secondary objectives were to assess compliance with expert recommendations on acute pain management in opioid-tolerant patients and to examine clinical outcomes. METHODS: A retrospective review of 812 systematically sampled adult SDA surgical cases between April 1, 2008 and March 31, 2009 was conducted. RESULTS: Among 798 eligible patients, 148 (18.5% [95% CI 15.9% to 21.2%]) were prescribed opioids, with 4.4% prescribed long-acting opioids (95% CI 3.0% to 5.8%). Use of opioids was most prevalent among orthopedic and neurosurgery patients. Among the 35 patients on long-acting opioids who had a high likelihood of being tolerant, anesthesiologists correctly identified 33, but only 13 (37%) took their usual opioid preoperatively while 22 (63%) had opioids continued postoperatively. Acetaminophen, nonsteroidal anti-inflammatory drugs and pregabalin were ordered preoperatively in 18 (51%), 15 (43%) and 18 (51%) cases, respectively, while ketamine was used in 15 (43%) patients intraoperatively. Acetaminophen, nonsteroidal anti-inflammatory drugs and pregabalin were ordered postoperatively in 31 (89%), 15 (43%) and 17 (49%) of the cases, respectively. No differences in length of stay, readmissions and emergency room visits were found between opioid-tolerant and opioid-naive patients. CONCLUSION: Opioid use is more common in SDA surgical patients than in the general population and is most prevalent within orthopedic and neurosurgery patients. Uptake of expert opinion on the management of acute pain in the opioid tolerant patient population is lacking.

Reducing persistent postoperative pain and disability 1 year after breast cancer surgery: a randomized, controlled trial comparing thoracic paravertebral block to local anesthetic infiltration.

BACKGROUND: The objective of this study was to compare the effect of thoracic paravertebral block (TPVB) and local anesthetic (LA) on persistent postoperative pain (PPP) 1 year following breast cancer surgery. Secondary objectives were to compare the effect on arm morbidity and quality of life. METHODS: Women scheduled for elective breast cancer surgery were randomly assigned to either TPVB or LA followed by general anesthesia. An NRS value of >3 at rest or with movement 1 year following surgery defined PPP. Blinded interim analysis suggested rates of PPP much lower than anticipated, making detection of the specified 20 % absolute reduction in the primary outcome impossible. Recruitment was stopped, and all enrolled patients were followed to 1 year. RESULTS: A total of 145 participants were recruited; 65 were randomized to TPVB and 64 to LA. Groups were similar with respect to demographic and treatment characteristics. Only 9 patients (8 %; 95 % CI 4-14 %) met criteria for PPP 1 year following surgery; 5 were in the TPVB and 4 in the LA group. Brief Pain Inventory severity and interference scores were low in both groups. Arm morbidity and quality of life were similar in both groups. The 9 patients with PPP reported shoulder-arm morbidity and reduced quality of life. CONCLUSIONS: This study reports a low incidence of chronic pain 1 year following major breast cancer surgery. Although PPP was uncommon at 1 year, it had a large impact on the affected patients' arm morbidity and quality of life.

Auditory-evoked potentials during coma: do they improve our prediction of awakening in comatose patients?

OBJECTIVE: The mismatch negativity (MMN), an auditory event-related potential, has been identified as a good indicator of recovery of consciousness during coma. We explored the predictive value of the MMN and other auditory-evoked potentials including brainstem and middle-latency potentials for predicting awakening in comatose patients after cardiac arrest or cardiogenic shock. MATERIALS AND METHODS: Auditory brainstem, middle-latency (Pa wave), and event-related potentials (N100 and MMN waves) were recorded in 17 comatose patients and 9 surgical patients matched by age and coronary artery disease. Comatose patients were followed up daily to determine recovery of consciousness and classified as awakened and nonawakened. RESULTS: Among the auditory-evoked potentials, the presence or absence of MMN best discriminated between patients who awakened or those who did not. Mismatch negativity was present during coma in all patients who awakened (7/7) and in 2 of those (2/10) who did not awaken. In patients who awakened and in whom MMN was detected, 3 of those awakened between 2 and 3 days and 4 between 9 and 21 days after evoked potential examination. All awakened patients had intact N100 waves and identifiable brainstem and middle-latency waves. In nonawakened patients, N100 and Pa waves were detected in 5 cases (50%) and brainstem waves in 9 (90%). CONCLUSIONS: The MMN is a good predictor of awakening in comatose patients after cardiac arrest and cardiogenic shock and can be measured days before awakening encouraging ongoing life support.

Patient function and caregiver burden after ambulatory surgery: a cohort study of patients older than 65.

PURPOSE: The primary objective of this prospective cohort study was to assess the impact of ambulatory surgery on patient function one week and one month following surgery among surgical patients ≥ 65 yr of age. Secondary objectives were to determine whether changes in patient function were correlated with increased burden of care in the patient's primary caregiver and with patient assessments of postoperative pain and quality of life. METHODS: Following Research Ethics Board approval, patients aged ≥ 65 yr undergoing elective ambulatory surgery and their caregivers were recruited. Patients completed the système de mesure de l'autonomie fonctionnelle (SMAF) and the Brief Pain Inventory. Primary caregivers completed the Zarit Burden Interview (ZBI). All measurements were obtained preoperatively and on postoperative days (POD) 7 and 30. RESULTS: Patient function decreased on POD 7 and had not returned to baseline on POD 30 (mean change in SMAF 6.9; 95% confidence interval (CI) 5.3 to 8.4 on POD 7 and mean change in SMAF 2.6; 95% CI 1.3 to 4.0 on POD 30). Interval changes in caregiver burden were not significant (mean change in ZBI -0.4; 95% CI -1.8 to 0.96 on POD 7 and mean change in ZBI -0.6; 95% CI -2.1 to 0.8 on POD 30). Decreased patient function was associated with increased caregiver burden at all time points (P < 0.001). Decreased caregiver function at baseline was also associated with higher ZBI (linear association 0.71; P = 0.02). CONCLUSIONS: Patients exhibited reduced function seven days following ambulatory surgery. Patient function largely recovered by POD 30. Caregiver burden was variable and influenced by both patient and caregiver function. This trial was registered with Clinical Trials.gov (NCT01382251).

Long-lasting functional disabilities in patients who recover from coma after cardiac operations.

BACKGROUND: Uncertainty regarding the long-term functional outcome of patients who awaken from coma after cardiac operations is difficult for families and physicians and may delay rehabilitation. We studied the long-term functional status of these patients to determine if duration of coma predicted outcome. METHODS: We followed 71 patients who underwent cardiac operations; recovered their ability to respond to verbal commands after coma associated with postoperative stroke, encephalopathy, and/or seizures; and were discharged from the hospital. The Glasgow Outcome Scale Extended (GOSE) was used to assess functional disability 2 to 4 years after discharge. Outcomes were classified as favorable (GOSE scores 7 and 8) and unfavorable (GOSE scores 1-6). RESULTS: Of 71 patients identified, 39 were interviewed, 15 died, 1 refused to be interviewed, and 16 were lost to follow-up. Of the 54 patients with completed GOSE evaluations, only 15 (28%) had favorable outcomes. Among patients with unfavorable outcomes, 15 (28%) died, 14 (26%) survived with moderate disabilities, and 10 (18%) had severe disabilities. Factors associated with unfavorable outcomes were increases in duration of coma (p = 0.007), time in intensive care (p = 0.006), length of hospitalization (p = 0.004), and postoperative serum creatine kinase levels (p = 0.006). Only duration of coma was an independent predictor of unfavorable outcome (odds ratio [OR], 1.25; 95% confidence interval [CI], 1.008-1.537; p = 0.042). Patients with durations of coma greater than 4 days were more likely to have unfavorable outcomes (OR, 5.1; 95% CI, 1.3-21.3; p = 0.02). CONCLUSIONS: Two thirds of comatose patients who survived to discharge after cardiac operations had unfavorable long-term functional outcomes. A longer duration of unconsciousness is a predictor of unfavorable outcome.

Comparison of the EuroSCORE and Cardiac Anesthesia Risk Evaluation (CARE) score for risk-adjusted mortality analysis in cardiac surgery.

OBJECTIVE: The European System for Cardiac Operative Risk Evaluation (EuroSCORE) and the Cardiac Anesthesia Risk Evaluation (CARE) score are risk indices designed in the mid-1990 s to predict mortality after cardiac surgery. This study assesses their ability to provide risk-adjusted mortality in a contemporary cardiac surgical population. METHODS: The mortality probability was estimated with the additive and logistic EuroSCORE, and CARE score, for 3818 patients undergoing cardiac surgery at one institution between 1 April 2006 and 31 March 2009. Model discrimination was obtained using the area under the receiver operating characteristics (ROC) curve and calibration using the appropriate chi-square goodness-of-fit test. Recalibration of risk models was obtained by logistic calibration, when needed. Calculation of risk-adjusted mortality was performed for the institution and eight surgeons, using each model before and when needed, after recalibration. RESULTS: The area under the ROC curve is 0.72 (95% confidence interval (CI): 0.71-0.74) with the additive EuroSCORE, 0.84 (95% CI: 0.83-0.85) with the logistic EuroSCORE, and 0.79 (95% CI: 0.78-0.81) with the CARE score. The additive and logistic EuroSCORE have poor calibration, predicting a hospital mortality of 6.24% and 7.72%, respectively, versus an observed mortality of 3.25% (P < 0.001). Consequently, the risk-adjusted mortality obtained with those models is significantly underestimated for the institution and all surgeons. The CARE score has good calibration, predicting a mortality of 3.38% (P = 0.50). The hospital risk-adjusted mortality with the recalibrated additive and logistic EuroSCORE and CARE score is 3.24% (95% CI: 3.05-3.43%), 3.25% (95% CI: 3.05-3.44%), and 3.12% (95% CI: 2.94-3.34%), respectively. The individual surgeons' risk-adjusted mortality is similar with the recalibrated EuroSCORE models and CARE score, identifying two surgeons with higher rates than the hospital average mortality. CONCLUSIONS: The original additive and logistic EuroSCORE models significantly overestimate the risk of mortality after cardiac surgery. However, after recalibration both models provide reliable risk-adjusted mortality results. Despite its lower discrimination as compared with the logistic EuroSCORE, the CARE score remains calibrated a decade after its development. It is as robust as the recalibrated additive and logistic EuroSCORE to perform risk-adjusted mortality analysis.

Predictors of duration of unconsciousness in patients with coma after cardiac surgery.

OBJECTIVES: To describe clinical and brain imaging characteristics of patients who recovered and did not recover consciousness from a coma after cardiac surgery and to investigate predictors of the duration of unconsciousness in those patients who ultimately recovered consciousness. DESIGN: A retrospective analysis from a cohort of patients who developed coma after cardiac surgery. SETTING: A single university hospital. PARTICIPANTS: One hundred twelve patients with postoperative stroke, encephalopathy, and/or seizures who remained in coma longer than 24 hours after cardiac surgery. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The authors analyzed the patients' perioperative and intraoperative characteristics, laboratory values, noncontrast head computed tomography (CT) scans, and outcomes. Patients who did not recover consciousness (n = 16) were more likely to have been classified preoperatively as New York Heart Association class III/IV (p = 0.037). In patients who recovered consciousness (n = 96), only increased preoperative serum creatinine was an independent predictor of a longer duration of unconsciousness (p = 0.011). In patients who eventually recovered consciousness and had no acute findings on brain imaging, preoperative creatinine (p = 0.014), the lowest postoperative hemoglobin (p = 0.039), and surgical emergency (p = 0.045) were independent predictors of the duration of unconsciousness (p = 0.002). In patients who regained consciousness but had acute findings on brain imaging, cardiogenic shock (p = 0.012) and the insertion of an intra-aortic balloon pump before or during surgery (p = 0.025) predicted longer durations of unconsciousness (p < 0.001). CONCLUSIONS: In patients who ultimately recovered consciousness after being in a coma for at least 24 hours after cardiac surgery and have no abnormality on a brain CT scan, elevated preoperative serum creatinine, urgent cardiac surgery, and lower postoperative hemoglobin were correlated with an increased duration of unconsciousness.

Cerebral emboli detected by transcranial Doppler during cardiopulmonary bypass are not correlated with postoperative cognitive deficits.

BACKGROUND AND PURPOSE: High-intensity transient signals (HITS) are the transcranial Doppler representation of both air and solid cerebral emboli. We studied the frequency of HITS associated with different surgical maneuvers during cardiopulmonary bypass for coronary artery bypass graft surgery and their association with postoperative cognitive dysfunction (POCD). METHODS: We combined 356 patients undergoing coronary artery bypass graft from 2 clinical trials who had both neuropsychological testing (before, 1 week and 3 months after surgery) and transcranial Doppler during cardiopulmonary bypass. HITS were grouped into periods that included: cannulation, cardiopulmonary bypass onset, aortic crossclamp-on, aortic crossclamp-off, side clamp-on, side clamp-off, and decannulation. POCD was defined by a decreased combined Z-score of at least 2.0 or reduction in Z-scores of at least 2.0 in 20% of the individual tests. RESULTS: Incidence of POCD was 47.3% and 6.3% at 1 week and 3 months after surgery. There was no association between cardiopulmonary bypass counts of HITS and POCD at 1 week (P=0.617) and 3 months (P=0.110). No differences in HITS counts were identified at any of the surgical periods between patients with and without POCD. Factors affecting HITS counts were surgical period (P<0.0001), blood flow velocity (P=0.012), cardiopulmonary bypass duration (P=0.040), and clinical study (P=0.048). CONCLUSIONS: Although cerebral microemboli have been implicated in the pathogenesis of POCD, in this study that included low-risk patients undergoing coronary artery bypass surgery, there was no demonstrable correlation between the counts of HITS and POCD.

Effects of mild hypothermia and rewarming on renal function after coronary artery bypass grafting.

BACKGROUND: Hypothermia is a potential strategy for visceral organ protection during cardiopulmonary bypass (CPB). We report data from two randomized studies evaluating mild hypothermia and rewarming on postoperative renal function in cardiac surgical patients. METHODS: Patients undergoing nonemergency, isolated coronary artery bypass grafting were enrolled into two studies. In the first, 223 patients were cooled to 32 degrees C during CPB and randomly assigned to rewarming to 37 degrees C (RW-37 degrees) or 34 degrees C (RW-34 degrees). The second study randomized 267 patients to sustained mild hypothermia at 34 degrees C (S-34 degrees) or normothermia (S-37 degrees) without rewarming. Serum creatinine levels were measured. Creatinine clearance was calculated. Significant renal dysfunction was defined as a 25% increase in serum creatinine or a 25% decrease in creatinine clearance postoperatively. RESULTS: Postoperative serum creatinine levels were persistently higher in the RW-37 degrees patients than in the RW-34 degrees group (p < 0.01). RW-37 degrees patients had a higher incidence of renal dysfunction (17%) than RW-34 degrees patients (9%, p = 0.07). Sustained mild hypothermia had no beneficial effect on postoperative serum creatinine levels (p = 0.44) or significant renal dysfunction: S-34 degrees, 20% vs S-37 degrees, 15% (p = 0.28). Diabetes (odds ratio [OR], 1.6; 95% confidence interval [CI] 1.3 to 2.1), prolonged CPB time (OR, 1.1; 95% CI, 1.0 to 1.2), and rewarming (OR, 1.4; 95% CI, 1.0 to 1.9) were independent risk factors for significant renal dysfunction. Renal dysfunction was associated with longer hospital stay (8.4 +/- 0.8 vs 6.8 +/- 04 days, p < 0.001). CONCLUSIONS: Sustained mild hypothermia does not improve renal outcome. However, rewarming on CPB is associated with increased renal injury and should be avoided.

A method to distinguish between gaseous and solid cerebral emboli in patients with prosthetic heart valves.

BACKGROUND: The difficulty of distinguishing solid from air emboli using transcranial Doppler has limited its use in situations where both types of emboli can occur, such as in mechanical heart valve patients. To make transcranial Doppler clinically useful, a method must be found to distinguish benign air bubbles from the more damaging solid particulates. Since inhalation of 100% oxygen reduces the amount of air bubbles in mechanical heart valve patients, the ultrasonic features of the remaining emboli would be characteristic of solid particulates. OBJECTIVE: We determined the accuracy of the signal relative intensity measured with transcranial Doppler to distinguish between gaseous and non-gaseous emboli in mechanical heart valve patients examined during room air and 100% oxygen. Embolic signals detected in patients with bioprosthetic valves examined during 100% oxygen comprised the source of solid particulates. METHODS: Embolic signals were detected during room air (n=141) and 100% oxygen (n=45) from 17 mechanical valve patients at two Doppler examinations (4h and 4 days after surgery). Solid embolic signals (n=31) from seven patients with bioprosthetic valves were identified with 100% oxygen within the first 4h after surgery. Frequency plots and receiver operating characteristic curves assessed signal intensity differences between mechanical and bioprosthetic valve groups during 100% oxygen and the efficacy of the relative intensity for differentiating gaseous from solid emboli. RESULTS: Administration of 100% oxygen during transcranial Doppler examination in mechanical heart valve patients decreased the count of embolic signals compared with room air (p=0.006). The embolic signals of mechanical heart valve patients breathing 100% oxygen showed lower relative intensities compared with those during room air. The distribution of the signal relative intensity between mechanical and bioprosthetic valve groups during 100% oxygen was similar. A 16dB cut-off threshold achieved the best accuracy for differentiating non-gaseous from gaseous emboli (sensitivity: 60%; specificity: 82%; area: 0.721; p<0.0001). CONCLUSIONS: The use of a signal intensity cut-off offers adequate discrimination of the embolic composition in mechanical heart valve patients. Future studies evaluating prophylactic treatments of thrombosis in these patients should assess the predictive value of this intensity threshold and their potential association with outcome indicators and procoagulant markers.

Effects of shed mediastinal blood on cardiovascular and pulmonary function: a randomized, double-blind study.

BACKGROUND: Shed mediastinal blood during cardiopulmonary bypass (cardiotomy blood) contains fat, particulate matter, and vasoactive mediators that can adversely affect the pulmonary and systemic vasculature, as well as impair gas exchange. Our aim was to evaluate the effects of processing cardiotomy blood on cardiovascular and pulmonary function after cardiac surgery. METHODS: Patients undergoing coronary artery bypass or aortic valve surgery, or both, using cardiopulmonary bypass were randomly allocated to receiving processed (treated, n = 132) or unprocessed shed blood (control, n = 134) In the treated group, shed blood was processed by centrifugation, washing, and additional filtration. Pulmonary function, arterial and venous blood gases, and hemodynamics were measured before, immediately after, and 2 hours after cardiopulmonary bypass in a consecutive subset of patients (n = 154). Patients and treating physicians were blinded to treatment assignment. RESULTS: Preoperative characteristics were similar between groups. There were no significant differences between groups in indexes of pulmonary mechanical function at any of the measured time points. Patients in the treated group demonstrated reduced pulmonary and systemic vascular resistance (both p < 0.01) as well as increased cardiac index in the perioperative period (2.6 +/- 0.07 versus 2.3 +/- 0.06 L . min(-1) . m(-2) at 2 hours after CPB, p = 0.004). Larger volumes of cardiotomy blood were associated with greater changes in systemic and pulmonary vascular resistance. Indicators of pulmonary gas exchange were similar between groups at all measured time points. Treated patients demonstrated a trend toward reduced length of ventilation (11.0 +/- 1.9 versus 13.9 +/- 2.4 hours, p = 0.12). CONCLUSIONS: Processing of shed mediastinal blood improves cardiopulmonary hemodynamics and may reduce ventilatory requirements after cardiac surgery.

Effects of sustained mild hypothermia on neurocognitive function after coronary artery bypass surgery: a randomized, double-blind study.

OBJECTIVE: Neurocognitive deficits occur frequently in patients undergoing cardiac surgery and may be caused, in part, by ischemic cerebral injury. Cerebral hypothermia has been proposed as a neuroprotective strategy to reduce ischemic injury in animal studies, in postcardiac arrest, and during cardiac surgery. We sought to evaluate the effects of sustained mild intraoperative hypothermia, without rewarming, on neurocognitive function after coronary artery bypass surgery. METHODS: Patients (aged >/= 60 years) undergoing non-urgent coronary surgery were randomized to an intraoperative nasopharyngeal temperature of 34 degrees C (hypothermic; n = 133) or 37 degrees C (normothermic; n = 134), maintained using water-circulating thermal control pads. No active rewarming was used. Transcranial Doppler was used intraoperatively to monitor middle cerebral artery emboli. Neuropsychometric testing, consisting of a battery of 16 tests, was performed by blinded observers preoperatively, before discharge, and at 3 months, and tests were divided into 4 cognitive domains. A deficit was prospectively defined as a 1 standard deviation decrease in individual scores from baseline in 1 or more domains. RESULTS: The number of intraoperative cerebral emboli was similar between the control and the treated groups (188 [115-331] vs 182 [100-305], P = .71). At discharge, neurocognitive deficits were present in 45% of control patients and in 49% of treated patients (P = .49) and at 3 months decreased to 8% in control patients and 4% in treated patients (P = .28). There was no correlation between the total number of cerebral emboli and the occurrence of neurocognitive deficits (r = -0.01; P = .88). Hypothermic patients demonstrated trends toward reduced intensive care unit stay (1.4 +/- 1.0 days vs 1.2 +/- 0.7 days, P = .06) and increased chest tube output (655 +/- 327 mL/24 h vs 584 +/- 325 mL/24 h, P = .09). CONCLUSIONS: Mild intraoperative hypothermia has no major adverse effects but does not decrease the incidence of neurocognitive deficits in patients undergoing coronary artery bypass surgery. In the absence of rewarming and cerebral hyperthermia, sustained mild hypothermia does not improve cognitive outcome.

The cardiotomy trial: a randomized, double-blind study to assess the effect of processing of shed blood during cardiopulmonary bypass on transfusion and neurocognitive function.

BACKGROUND: Reinfusion of unprocessed cardiotomy blood during cardiac surgery can introduce particulate material into the cardiopulmonary bypass circuit, which may contribute to postoperative cognitive dysfunction. On the other hand, processing of this blood by centrifugation and filtration removes coagulation factors and may potentially contribute to coagulopathy. We sought to evaluate the effects of cardiotomy blood processing on blood product use and neurocognitive functioning after cardiac surgery. METHODS AND RESULTS: Patients undergoing coronary and/or aortic valve surgery using cardiopulmonary bypass were randomized to receive unprocessed blood (control, n=134) or cardiotomy blood that had been processed by centrifugal washing and lipid filtration (treatment, n=132). Patients and treating physicians were blinded to treatment assignment. A strict transfusion protocol was followed. Blood transfusion data were analyzed using Poisson regression models. The treatment group received more intraoperative red blood cell transfusions (0.23+/-0.69 U versus 0.08+/-0.34 U, P=0.004). Both red blood cell and nonred blood cell blood product use was greater in the treatment group and postoperative bleeding was greater in the treatment group. Patients were monitored intraoperatively by transcranial Doppler and they underwent neuropsychometric testing before surgery and at 5 days and 3 months after surgery. There was no difference in the incidence of postoperative cognitive dysfunction in the 2 groups (relative risk: 1.16, 95% CI: 0.86 to 1.57 at 5 days postoperatively; relative risk: 1.05, 95% CI: 0.58 to 1.90 at 3 months). There was no difference in the quality of life nor was there a difference in the number of emboli detected in the 2 groups. CONCLUSIONS: Contrary to expectations, processing of cardiotomy blood before reinfusion results in greater blood product use with greater postoperative bleeding in patients undergoing cardiac surgery. There is no clinical evidence of any neurologic benefit with this approach in terms of postoperative cognitive function.