Biomedical subjects

Barbara Phillips-Bute

Publications and source records attributed to Barbara Phillips-Bute.

24 records · Page 2Linked to original sources

PubMed2002

The rewarming rate and increased peak temperature alter neurocognitive outcome after cardiac surgery.

UNLABELLED: Neurocognitive dysfunction is a common complication after cardiac surgery. We evaluated in this prospective study the effect of rewarming rate on neurocognitive outcome after hypothermic cardiopulmonary bypass (CPB). After IRB approval and informed consent, 165 coronary artery bypass graft surgery patients were studied. Patients received similar surgical and anesthetic management until rewarming from hypothermic (28 degrees -32 degrees C) CPB. Group 1 (control; n = 100) was warmed in a conventional manner (4 degrees -6 degrees C gradient between nasopharyngeal and CPB perfusate temperature) whereas Group 2 (slow rewarm; n = 65) was warmed at a slower rate, maintaining no more than 2 degrees C difference between nasopharyngeal and CPB perfusate temperature. Neurocognitive function was assessed at baseline and 6 wk after coronary artery bypass graft surgery. Univariable analysis revealed no significant differences between the Control and Slow Rewarming groups in the stroke rate. Multivariable linear regression analysis, examining treatment group, diabetes, baseline cognitive function, and cross-clamp time revealed a significant association between change in cognitive function and rate of rewarming (P = 0.05). IMPLICATIONS: Slower rewarming during cardiopulmonary bypass (CPB) was associated with better cognitive performance at 6 wk. These results suggest that a slower rewarming rate with lower peak temperatures during CPB may be an important factor in the prevention of neurocognitive decline after hypothermic CPB.

Body Temperature↗

PubMed2002

Mitral flow propagation velocity identifies patients with abnormal diastolic function during coronary artery bypass graft surgery.

UNLABELLED: Flow propagation velocity (Vp) is a new method of assessing left ventricular (LV) diastolic (D) function that seems to be insensitive to heart rate and preload changes. We hypothesized that Vp <50 cm/s identifies patients with D dysfunction and that Vp provides an assessment of D function when standard Doppler techniques are uninterpretable. We conducted a prospective Doppler echocardiographic assessment of D function in 63 patients undergoing coronary artery bypass graft surgery. Doppler derivatives of mitral inflow and pulmonary vein flow profiles as well as isovolumic relaxation time were compared with Vp before and after cardiopulmonary bypass. A Valsalva maneuver was used to decrease preload. All patients with D dysfunction had Vp <50 cm/s. A Valsalva maneuver did not affect Vp. Vp remained a reliable measure of LV D function when mitral flow profiles could not be determined because of changes in heart rate and rhythm. LV filling patterns did not change significantly after cardiopulmonary bypass. We conclude that Vp is a simple measure of D function during coronary artery bypass graft surgery that correlates with standard, load-dependent Doppler echocardiographic techniques to identify D dysfunction. Vp <50 cm/s identifies abnormal D function in this patient population. IMPLICATIONS: Mitral propagation velocity (Vp) is a simple, reproducible measure of diastolic function during coronary artery bypass graft surgery that correlates with standard Doppler echocardiographic techniques to identify dysfunction in the setting of a rapid heart rate or variable preload. Vp <50 cm/s identifies abnormal diastolic function in this patient population.

Aged↗

PubMed2002

Postoperative hyperthermia is associated with cognitive dysfunction after coronary artery bypass graft surgery.

BACKGROUND AND PURPOSE: Temperature is a well-known modulator of experimental cerebral injury. We hypothesized that hyperthermia would be associated with a worsened cognitive outcome after coronary artery bypass graft surgery (CABG). METHODS: Three hundred consenting patients undergoing cardiopulmonary bypass for CABG had hourly postoperative temperatures recorded. The degree of postoperative hyperthermia was determined by using the maximum temperature within the first 24 hours as well as by calculating the area under the curve for temperatures >37 degrees C. Patients underwent a battery of cognitive testing both before surgery and 6 weeks after surgery. By use of factor analysis, 4 cognitive domains (scores) were identified, and the mean of the 4 scores was used to calculate the cognitive index (CI). Cognitive change was calculated as the 6-week CI minus the baseline CI. Multivariable linear regression (controlling for age, baseline cognitive function, and temperature during cardiopulmonary bypass) was used to compare postoperative hyperthermia with the postoperative cognitive change. RESULTS: The maximum temperature within the first 24 hours after CABG ranged from 37.2 degrees C to 39.3 degrees C. There was no relationship between area under the curve for temperatures >37 degrees C and cognitive dysfunction (P=0.45). However, the maximum postoperative temperature was associated with a greater amount of cognitive dysfunction at 6 weeks (P=0.05). CONCLUSIONS: This is the first report relating postoperative hyperthermia to cognitive dysfunction after cardiac surgery. Whether the hyperthermia caused the worsened outcome or whether processes that resulted in the worsened cognitive outcome also produced hyperthermia requires further investigation. In addition, interventions to avoid postoperative hyperthermia may be warranted to improve cerebral outcome after cardiac surgery.

Area Under Curve↗

PubMedDate not supplied

Brief report: The declining incidence of cerebral hyperthermia during cardiac surgery: a seven-year experience in 6,334 patients.

PURPOSE: Cerebral hyperthermia during rewarming from hypothermic cardiopulmonary bypass (CPB) commonly occurs and has been associated with postoperative neurocognitive dysfunction. Increased awareness of this has likely led to changes in rewarming strategies, including the reduction of rewarming rates and lowering of target rewarming temperatures. As a result, we hypothesized that the maximum temperature reached during cardiac surgery has decreased at our institution over time. METHODS: We retrospectively reviewed the maximum intraoperative nasopharyngeal (NP) temperature in 6,334 patients having undergone cardiac surgery utilizing hypothermic CPB from January 1993 to June 2000. The incidence of cerebral hyperthermia (defined by a NP temperature > 38 degrees C) was examined over time using Chi-square testing and the relationship between maximum temperature and date of surgery was studied using linear regression. RESULTS: Maximum temperature decreased over time (P < 0.0001; r2 = 0.40) having the greatest reduction from January 1993 to December 1996 (0.34 degrees C temperature drop per year), while from January 1997 to June 2000, it continued to decrease, but at a slower rate (0.10 degrees C per yr; P < 0.0001). The incidence of cerebral hyperthermia decreased over time with 83% of the first 10% of patients and 3% of the latter 10% of patients during the study period having a maximum temperature > 38 degrees C (P < 0.0001). CONCLUSION: The incidence of cerebral hyperthermia has decreased at our institution suggesting that a change in temperature management has occurred at our institution from January 1993 to June 2000 thereby outlining a temporal evolution in temperature management during CPB.

Aged↗

PubMedDate not supplied

Iliohypogastric-ilioinguinal peripheral nerve block for post-Cesarean delivery analgesia decreases morphine use but not opioid-related side effects.

PURPOSE: To examine if ilioinguinal-iliohypogastric nerve block could reduce the need for post-Cesarean delivery morphine analgesia and thus reduce the incidence of opioid related adverse-effects. METHODS: A multi-level technique for performing the nerve block with bupivacaine was developed and then utilized in this two-part study. Part one was a retrospective assessment of Cesarean delivery patients with and without ilioinguinal-iliohypogastric blocks to determine if the technique reduced patient controlled analgesia morphine use and thus would warrant further study. The second phase was a randomized double-blind placebo-controlled trial to compare post-Cesarean morphine use and the appearance of opioid-related side effects between the anesthetic and placebo-injected groups. RESULTS: Both phases demonstrated that our method of ilioinguinal-iliohypogastric nerve block significantly reduced the amount of iv morphine used by patients during the 24 hr following Cesarean delivery. In the retrospective assessment, morphine use was 49 +/- 30 mg in the block group vs 79 +/- 25 mg in the no block group (P = 0.0063). For the prospective trial, patients who received nerve blocks with bupivacaine had a similar result, self-administering 48 +/- 27 mg of morphine over 24 hr compared to 67 +/- 28 mg administered by patients who received infiltrations of saline. However, despite the significant decrease in morphine use, there was no reduction in opioid-related adverse effects: the incidences of nausea were 41% and 46% (P = 0.70) and for itching were 79% and 63% (P = 0.25) in the placebo and nerve block groups, respectively. CONCLUSION: A multi-level ilioinguinal-iliohypogastric nerve block technique can reduce the amount of systemic morphine required to control post-Cesarean delivery pain but this reduction was not associated with a reduction of opioid related adverse effects in our study group.

Adult↗

PubMedDate not supplied

Association of neurocognitive function and quality of life 1 year after coronary artery bypass graft (CABG) surgery.

OBJECTIVE: Although coronary artery bypass grafting (CABG) has been shown to improve quality of life and functional capacity for many patients, recent studies have demonstrated that a significant number of patients exhibit impairment in cognitive function immediately following surgery and beyond. We sought to determine the impact of this postoperative cognitive dysfunction on quality of life (QOL) and to characterize the dysfunction from the patient's perspective. METHODS: With Institutional Review Board (IRB) approval and written informed consent, 732 patients at Duke University Hospital undergoing CABG were enrolled. Five hundred fifty-one (75%) completed baseline, 6-week, and 1-year neurocognitive tests and psychometric measures designed to assess QOL. Neurocognitive status was assessed by a composite cognitive index score representing the mean of the scores in four cognitive domains. Change in QOL was assessed by subtracting baseline from 1-year scores for each of 10 QOL measures. The association between QOL and cognitive dysfunction was investigated using multivariable linear regression analysis. RESULTS: Cognitive decline limited improvement in QOL, with substantial correlation between change in cognition and change in QOL. One-year QOL measures are associated with both 6-week and 1-year change in cognition (Instrumental Activities of Daily Living, p < .0001; Duke Activity Status Index, p < .02; Cognitive Difficulties, p < .0001; Symptom Limitations, p = .0001; Center for Epidemiologic Study Depression, p < .0001; General Health Perception, p = .0001). CONCLUSIONS: Postoperative cognitive decline may diminish improvements in QOL. Strategies to reduce cognitive decline may allow patients to achieve the maximum improvement in QOL afforded by CABG, as even short-term cognitive dysfunction has implications for QOL 1 year later.

Aged↗