Postoperative cognitive dysfunction after sevoflurane or propofol general anaesthesia in combination with spinal anaesthesia for hip arthroplasty.

It is unknown if the type of general anaesthetic used for maintenance of anaesthesia affects the incidence of postoperative cognitive dysfunction (POCD). The aim of this study was to compare the incidence of POCD in patients administered either sevoflurane or propofol for maintenance of anaesthesia during total hip replacement surgery. Following administration of a spinal anaesthetic, patients received either sevoflurane (n=121) or propofol (n=171) at the discretion of the anaesthetist for maintenance of general anaesthesia to maintain the processed electroencephalogram (bispectral index, BIS) under 60. POCD was assessed postoperatively at day 7, three months, and 12 months using a neurocognitive test battery. There was no statistically significant difference between the incidence of POCD at any timepoint with sevoflurane compared to propofol. The mean BIS was significantly lower in the sevoflurane group than in the propofol group (mean BIS 44.3 [standard deviation, SD 7.5] in the sevoflurane group versus 53.7 [SD 8.1] in the propofol group, P=0.0001). However, there was no statistically significant association between intraoperative BIS level and the incidence of POCD at any timepoint. Our results suggest that the incidence of POCD is not strongly influenced by the type of anaesthesia used in elderly patients.

Incidence of postoperative cognitive dysfunction after general or spinal anaesthesia for extracorporeal shock wave lithotripsy.

BACKGROUND: Since general anaesthesia invariably accompanies surgery, the contribution of each to the development of postoperative cognitive dysfunction (POCD) has been difficult to identify. METHODS: A prospective randomized controlled trial was undertaken in elderly patients undergoing extracorporeal shock wave lithotripsy (ESWL). Between 2005 and 2011, 2706 individuals were screened to recruit 100 eligible patients. Patients were randomly assigned to receive general or spinal anaesthesia alone. A battery of eight neuropsychological tests was administered before operation and at 7 days and 3 months after operation. The reliable change index was used to calculate the incidence of POCD. Intention-to-treat analysis was used to compare rates of POCD. RESULTS: Futility analysis led to stopping of the trial after recruitment of 100 patients. Fifty patients were randomly assigned to general anaesthesia, and 48 patients to spinal anaesthesia without sedation or postoperative opioids. At 3 months, POCD was detected in 6.8% [95% confidence interval (CI): 1.4-18.7%] of patients in the general anaesthesia group and 19.6% (95% CI: 9.4-33.9%) in the spinal group (P=0.07). At 7 days after operation, the incidence of POCD was 4.1% (95% CI: 0.5-14%) in the general anaesthesia group and 11.9% (95% CI: 4.0-26.6%) in the spinal group (P=0.16). CONCLUSIONS: We found no significant difference in the rates of POCD when comparing general anaesthesia with spinal anaesthesia, suggesting that the surgical or procedural process itself may contribute to the development of POCD. CLINICAL TRIAL REGISTRATION: Australian Clinical Trials Registry number ACTRN12605000150640.

Review of transcranial Doppler ultrasound to detect microemboli during orthopedic surgery.

Transcranial Doppler ultrasonography has been used to detect microemboli in the middle cerebral artery during orthopedic surgery. We conducted a comprehensive systematic literature review of transcranial Doppler ultrasonography in orthopedic surgery to evaluate its status in this setting. Fourteen studies were selected for qualitative analysis. The highest number of patients studied was 45; emboli were detected in all studies, occurring in 20%-100% of patients. Most embolic counts were below 10, but some high counts were noted. No study reported all the technical parameters of the transcranial Doppler ultrasonography. All studies assessed neurologic status, and 6 studies evaluated cognitive function postoperatively. No study identified an association between postoperative cognitive function and embolic count. Six studies sought the presence of right-to-left shunts.

Concurrent intracardiac metastasis in a patient with intestinal perforation.

The administration of anaesthesia to subjects with intracardiac lesions poses the potential for cardiac complications. Cardiac metastases should be identified in susceptible cases and transthoracic echocardiography performed to elucidate the nature of the cardiac lesions. We describe a case of an intracardiac metastasis in a 65-year-old subject with a small bowel tumour leading to intestinal perforation and presenting for surgical treatment. Oncological assessment of the situation, in conjunction with the anaesthetic risks, led to abandonment of surgery and palliative treatment.

Defining intra-operative hypotension--a pilot comparison of blood pressure during sleep and general anaesthesia.

The scientific justification for particular values of intra-operative hypotension is poorly substantiated. To provide a rationale for appropriate values we recorded blood pressure measurements at home for 24 h using an automated non-invasive ambulatory blood pressure measurement device. These blood pressures were compared with blood pressure measured before and during general anaesthesia in 18 subjects undergoing elective day surgery. We confirmed that a pre-operative reading taken upon admission to hospital is significantly elevated compared to a usual daytime blood pressure in the same patient. The median (IQR [range]) increases in systolic and mean arterial pressures were 10 (2-15 [-5 to 59]) mmHg, p = 0.003 and 10 (5-14 [-5 to 35]) mmHg, p = 0.002, respectively. When using this admission blood pressure measurement as a 'baseline', systolic and mean arterial pressures decreased during sleep by 41 (30-46 [6-83]) mmHg and 34 (26-36 [6-58]) mmHg, respectively (p = 0.001). This decreased even further intra-operatively: systolic blood pressure by 49 (36-64 [15-96]) mmHg and mean arterial pressure by 36 (26-46 [8-66]) mmHg (p = 0.001).

Cognitive function in patients undergoing coronary angiography.

OBJECTIVE: To measure cognition in patients before and after coronary angiography. DESIGN: Prospective observational cohort study. SETTING: University teaching hospital. PATIENTS: 56 patients presenting for elective coronary angiography. MAIN OUTCOME MEASURES: Computerised cognitive test battery administered before coronary angiography, before discharge from hospital and 7 days after discharge. A matched healthy control group was used as a comparator. RESULTS: When analysed by group, coronary angiography patients performed worse than matched controls at each time point. When the cognitive change was examined for each individual, of the 48 patients tested at discharge, 19 (39.6%) were classified as having a new cognitive dysfunction, and of 49 patients tested at day 7, six (12.2%) were classified as having a new cognitive dysfunction. CONCLUSIONS: The results confirm that cognitive function is decreased in patients who have cardiovascular disease. Furthermore, coronary angiography may exacerbate this impaired cognition in some patients.

A prospective observational study of the effect of night duty on the cognitive function of anaesthetic registrars.

The issue of fatigue in hospital medical staff represents a potential health and safety risk to both staff and patients, and is receiving worldwide interest. We aimed to characterize the cognitive performance of anaesthetic registrars before and after a series of night shifts. We enrolled nine full-time anaesthetic trainees in an Australian adult tertiary-referral hospital. We conducted a cross-over observational study which tested cognitive performance in participants before and after seven consecutive night shifts and compared this with performance before and after seven consecutive day shifts. Cognitive function was measured using a computerized assessment tool. Participants completed a mean of 62.5% of the requested testing (seven participants completed 87%). There was no significant change in performance before or after any day shift, nor at the commencement of each night shift. There was near perfect accuracy in performance in all tests at all times. There was a statistically significant deterioration in speed of performance for detection and identification tasks at the end of night shift as the week progressed. Anaesthetic registrars demonstrate a significant decline in cognitive performance after a series of night shifts.

The sensitivity and specificity of three common statistical rules for the classification of post-operative cognitive dysfunction following coronary artery bypass graft surgery.

BACKGROUND: The application of statistical rules to determine post-operative cognitive dysfunction (POCD) has varied, and partially explains the wide range of reported incidences of POCD in the literature. The current study assessed the sensitivity and specificity of three commonly used statistical rules in a sample of coronary artery bypass graft (CABG) patients and healthy non-surgical controls. METHODS: Two hundred and four CABG patients [mean age, 68.8 years; standard deviation (SD), 7.0 years] completed neuropsychological assessment pre-operatively (baseline) and 1 week and 3 months post-operatively. Ninety age- and gender-matched non-surgical controls (mean age, 67.8 years; SD, 7.9 years) completed the same tasks at the same time points. POCD was determined in each group using three rules: the 1SD decline on two or more tasks; the 20% decline on 20% of tasks rule; and a modified reliable change index. RESULTS: The modified reliable change index demonstrated the greatest combination of sensitivity and specificity. The 20% decline on 20% of tasks rule detected the largest incidence of impairment in the CABG group, but showed large incidences of false positive classifications in the control group. The 1SD rule detected the lowest incidence of POCD in the CABG group, but detected a larger incidence of impairment in the control group. CONCLUSIONS: The use of the modified reliable change index is recommended, given the sensitivity to change it displayed and the low rates of false positive classification in the control sample. The use of control groups in future research is also recommended.

Detection of cognitive decline after coronary surgery: a comparison of computerized and conventional tests.

BACKGROUND: Postoperative cognitive decline is a common complication after coronary artery bypass graft (CABG) surgery. Postoperative cognitive decline is defined on the basis of change in cognitive function detected with repeated assessments using neuropsychological tests. Therefore improvement in neuropsychological testing instruments may increase our understanding of postoperative cognitive decline. METHODS: Fifty patients undergoing CABG surgery completed both a conventional and a computerized battery of tests before and 6 days after CABG surgery. Fifty age- and education-matched controls completed the same test batteries 6 days apart. The reliability and the sensitivity to postoperative cognitive decline were computed for each battery. RESULTS: Both test batteries detected postoperative cognitive decline 6 days after CABG surgery. For the computerized battery, the reliability of the reaction times (intraclass correlation 0.89-0.92) was greater than for any test from the conventional battery (intraclass correlation 0.56-0.71), although accuracy measures were less reliable (intraclass correlation 0.61-0.89). The computerized battery detected all the cases of POCD identified by the conventional test battery and also five cases that were classified as normal by the conventional tests. CONCLUSION: Computerized tests are suitable for measuring cognitive change after CABG surgery and may detect change in a greater proportion of patients 6 days after CABG surgery than conventional neuropsychological tests.

Early extubation after cardiac surgery: emotional status in the early postoperative period.

OBJECTIVE: To compare the emotional state during the first 3 days after coronary artery surgery of patients who had undergone early versus conventional extubation. DESIGN: A prospective, randomized, controlled trial. SETTING: University hospital, single center. PARTICIPANTS: Eligible patients (n = 100) presenting for elective coronary artery surgery, randomized to an early extubation group or a conventional extubation group. INTERVENTIONS: Emotional status was measured by the Hospital Anxiety and Depression Scale (HAD), the Self Assessment Manikin (SAM), and the Multiple Affect Adjective Check List-Revised (MAACL-R). Tests were administered preoperatively and on the 1st and 3rd days postoperatively. MEASUREMENTS AND MAIN RESULTS: Of patients in the conventional extubation group, 30% showed moderate-to-severe depressive symptoms (HAD score >10) on day 3 postoperatively compared with 8% of patients in the early extubation group (p = 0.02). There was a clinically insignificant increase in MAACL-R depression score on the 1st postoperative day within both groups but no other differences within or between groups in SAM or MAACL-R scores. CONCLUSION: Early extubation results in fewer patients displaying depressive symptoms on the 3rd postoperative day but appears to have little effect on other measurements of emotional status. Anesthetic management during coronary artery bypass graft surgery may play an important role in the overall well-being of the patient by decreasing the incidence of postoperative depression.

Blood loss in elective coronary artery surgery: a comparison of centrifugal versus roller pump heads during cardiopulmonary bypass.

OBJECTIVES: To compare the effects of centrifugal pumps versus roller pumps for cardiopulmonary bypass (CPB) in routine cardiac surgery on hematologic parameters in the context of modern practice. DESIGN: Prospective, randomized, partially blinded. SETTING: University teaching hospital. PARTICIPANTS: Elective coronary artery surgery patients (n = 113) INTERVENTION: Patients were randomized to be perfused with either a roller head (group R, n = 56) or a centrifugal head (group C, n = 57) pump. Patients received epsilon-aminocaproic acid before and during CPB. Core body temperatures were allowed to drift down to approximately 32 degrees C. MEASUREMENTS AND MAIN RESULTS: Postoperative chest tube blood loss, blood product requirements, hemoglobin, and platelet counts were assessed. There were no significant differences in preoperative or intraoperative parameters, including CPB time, complexity of procedure, and minimum core temperature. There were the expected reductions in hemoglobin and platelet levels post-CPB in both groups to a similar extent. Chest tubes remained in situ for similar durations, and the final volume of drainage was not significantly different (group C, 1300 +/- 92 mL; group R 1117 +/- 83 mL; p = 0.14). Allogeneic blood was given to 23% of patients in group C and 18% in group R (p = 0.63). Aspirin was associated with an increase in early chest tube drainage. CONCLUSIONS: In this surgical and perfusion environment, the authors were unable to show an advantage, from the hematologic point of view, in the routine use of a centrifugal pump head in elective coronary artery surgical patients. The use of antifibrinolytic agents and mild hypothermia may have effects on hemostasis that overshadow the influence of pump head design in this type of surgery.

Neuropsychologic testing within 18 hours after cardiac surgery.

OBJECTIVE: To undertake neuropsychologic testing within 18 hours of cardiac surgery after fast-track anesthesia. DESIGN: Prospective study. SETTING: University hospital, single center. PARTICIPANTS: Fifty patients undergoing first-time elective coronary artery surgery. INTERVENTIONS: A neuropsychologic test battery was administered preoperatively and 18 hours and 5 days after surgery. MAIN RESULTS: Seven patients were withdrawn, and 9 patients did not attempt the postoperative tests (on both occasions) because of medical complications. Thirty patients completed > or =4 tests at both postoperative occasions. Of these, 9 patients (30%) showed a deficit in > or =2 tests at 18 hours postoperatively, and 3 (10%) showed a deficit at 5 days postoperatively. CONCLUSION: In the absence of medical complications and despite the difficulties, early postoperative neuropsychologic testing is possible after fast-track anesthesia. Such testing has the potential to more clearly define the course of cognitive decline after cardiac surgery.

Epidural fentanyl reduces the shivering threshold during epidural lidocaine anesthesia.

UNLABELLED: Epidural local anesthetics and IV opioids both decrease the core temperature that triggers shivering. However, the effect of epidural opioids on shivering thresholds has not been assessed. In this study, we tested the hypothesis that adding epidural fentanyl to epidural lidocaine decreases the shivering threshold compared with epidural lidocaine alone. Fourteen healthy male patients undergoing extracorporeal shockwave lithotripsy under epidural anesthesia were randomly assigned to receive either epidural lidocaine or epidural lidocaine plus epidural fentanyl. Ice-cold lactated Ringer's solution was given IV before epidural blockade, and the core temperature that triggers shivering was established. Then epidural anesthesia was induced, and the shivering threshold was established again after lithotripsy. Results were analyzed using paired or unpaired t-tests. Reduction in the shivering threshold by epidural anesthesia was significantly greater when fentanyl was added to lidocaine than when lidocaine was used alone (mean +/- SD: -0.6+/-0.4 degrees C versus -0.1+/-0.4 degrees C; P < 0.02). We conclude that patients are at increased risk of hypothermia when fentanyl is added to epidural lidocaine. IMPLICATIONS: Fentanyl is often added to lidocaine to improve the quality of epidural blockade and to reduce side effects. However, this study shows that patients are at increased risk of hypothermia when fentanyl is added to lidocaine.

Early extubation following coronary artery bypass surgery: a prospective randomized controlled trial. The Fast Track Cardiac Care Team.

STUDY OBJECTIVES: To determine the safety of early extubation (EE) after coronary artery surgery. DESIGN: Prospective randomized controlled trial. SETTING: The cardiac surgery operating room and ICU of a university-affiliated teaching hospital. PATIENTS: One hundred eligible patients presenting for elective coronary artery surgery. INTERVENTIONS: Patients randomized to the EE group were administered a reduced dose of fentanyl (15 microg/kg) and an anesthetic compatible with EE, while patients randomized to the conventional extubation (CE) group were given fentanyl (50 microg/kg). MEASUREMENTS AND RESULTS: The time to extubation in the EE group (median, 240 min; range, 30 to 930 min) was significantly less than the CE group (median, 420 min; range, 125 to 1,140 min) (p<0.01). Twenty patients were withdrawn from the study according to protocol guidelines. There were no cases of reintubation or complications attributable to EE. CONCLUSIONS: By using an appropriate anesthetic technique and postoperative management, EE can be achieved following coronary artery bypass surgery without major complications.

Superficial and deep cervical plexus block for carotid artery surgery: a prospective study of 1000 blocks.

BACKGROUND AND OBJECTIVES: Cervical plexus blocks are performed for carotid surgery to allow neurological assessment of the awake patient. The aim of this study was to establish the frequency of success, complications, and patient acceptance of the technique. METHODS: One thousand superficial and deep cervical blocks were performed in 924 patients having carotid artery surgery. Data about the blocks were recorded prospectively and patients were followed up postoperatively by an independent anesthesiologist to assess patient acceptance of the technique. RESULTS: Lidocaine was the most frequently used anesthetic (88%). Surgical supplementation of the blocks was required in 53% of operations. Six blocks (0.6%) had clinical evidence of intravascular injection of local anesthetic. Sedation was required in 66% of operations and conversion to general anesthesia occurred in 25 (2.5%) of operations. Ninety-one percent of patients reported no problems with the block, and 93% stated that they would have the same anesthetic for any future similar surgery. CONCLUSIONS: We conclude that superficial and deep cervical plexus block has a high success rate, low complication rate, and high patient acceptance rate. Caution should, however, be exercised to ensure a low intravascular injection rate which is of most concern with this technique, because blood was aspirated in 30% of patients during performance of the block.

Combined general and epidural anesthesia versus general anesthesia for major abdominal surgery: postanesthesia recovery characteristics.

BACKGROUND AND OBJECTIVES: Outcome studies comparing general anesthesia combined with epidural anesthesia (GEN-EPI) to general anesthesia (GEN) for major abdominal surgery have been equivocal. However, many believe that patients anesthetized with GEN-EPI fair better than GEN. This study tests the hypothesis that there are favorable recovery characteristics associated with GEN-EPI as compared with GEN following abdominal surgery. METHODS: A prospective randomized double-blind trial, consisting of 30 patients ages 18-74 undergoing abdominal surgery was undertaken. Patients received either GEN-EPI or GEN by standardized protocol. At the end of surgery the epidural catheter was removed and psychological testing was performed over 24 hours to determine recovery characteristics. These included the modified Slater test, the Self-Assessment Manikin, the Kendrick Digital Copying Test, the Hospital Anxiety and Depression Scale, as well as visual analog scales for pain and appearance. RESULTS: Patients receiving GEN-EPI emerged from anesthesia faster (P < .03) with less pain on awakening (P < .04 at rest; P < .01 on coughing), had better psychomotor function at 2 hours (P < .04), and were less drowsy at 4 hours (P < .04), than patients with GEN. There was no difference in pain intensity after the initial assessment, morphine usage, mood, anxiety, and depression at any other measurement period. CONCLUSION: Transient quantifiable differences in recovery characteristics exist between patients receiving GEN-EPI and GEN.

Comparison of clonidine and epinephrine in lidocaine for cervical plexus block.

BACKGROUND AND OBJECTIVES: Carotid endarterectomy under cervical plexus block offers the advantage of awake neurologic assessment. The hypothesis was tested that the addition of clonidine 5 micrograms/mL to lidocaine 1.5% for the block is as effective clinically as the addition of epinephrine 5 micrograms/mL but without the associated tachycardia. METHODS: In a double-blind, randomized, prospective trial of 40 patients, local anesthetic solutions of lidocaine 1.5% containing either clonidine 5 micrograms/mL or epinephrine 5 micrograms/mL were compared for cervical plexus block in patients undergoing carotid endarterectomy. Each solution was administered to 20 patients with a total lidocaine dose of 7 mg/kg. The electrocardiogram, heart rate, and arterial pressure (radial artery catheter) were continuously monitored. Blood samples were drawn for determination of serum lidocaine levels during the first hour. RESULTS: The block onset time (8.4 +/- 0.6 minutes for epinephrine, 8.8 +/- 0.8 minutes for clonidine) and duration (139 +/- 6.7 minutes for epinephrine, 148 +/- 5.8 minutes for clonidine) were not different between the two groups. During the period from completion of the block until incision there was a significant heart rate increase in the epinephrine group (23% mean rise) as compared with the clonidine group (4% mean rise) (P < .003). There was no difference in blood pressure between the two groups. The maximum plasma concentrations of lidocaine were 2.5-7.6 micrograms/mL (mean, 4.5 +/- 0.3 micrograms/mL) for the epinephrine group and 4.7-18.4 micrograms/mL (mean, 7.5 +/- 0.7 micrograms/mL) for the clonidine group (P < .0002). The maximum concentrations were reached 0-30 minutes (mean, 8 +/- 1.4 minutes) after injection for the epinephrine group and 0-10 minutes (mean, 4.5 +/- 7.1 minutes) for the clonidine group (P < .03). CONCLUSIONS: Clonidine 5 micrograms/mL is a useful additive to lidocaine 1.5% for cervical plexus block to reduce the incidence of tachycardia; however, omission of epinephrine results in higher serum lidocaine levels.

Comparative effects of plain and epinephrine-containing bupivacaine on the hemodynamic response to cervical plexus anesthesia in patients undergoing carotid endarterectomy.

OBJECTIVES: This study was designed to investigate whether the addition of epinephrine as a vasoconstrictor additive to local anesthetic affects the hemodynamic profile after cervical plexus block in patients presenting for carotid endarterectomy. DESIGN: A prospective, double-blind, randomized trial. SETTING: A university hospital. PARTICIPANTS: Forty patients scheduled for carotid endarterectomy under regional anesthesia (cervical plexus block). INTERVENTIONS: Patients were randomized to one of two groups. Group P (20 patients) received plain bupivacaine; group E (20 patients) received bupivacaine with epinephrine, 5 micrograms/mL. All patients received 2 mg/kg of bupivacaine, and group E received 2 micrograms/kg of epinephrine. The electrocardiogram and intra-arterial blood pressure were monitored continuously, and recordings of heart rate and blood pressure were recorded at predetermined intervals from before the block until the skin incision. RESULTS: After the block, group E developed a sustained increase in heart rate of approximately 15% (p < 0.01), whereas group P showed no change. Systolic blood pressure increased significantly with time over the study period in both groups (p < 0.01). Diastolic blood pressure increased significantly in group P (p < 0.01) but not in group E. CONCLUSIONS: Concerning cervical plexus block with bupivacaine, the use of epinephrine is associated with an increase in heart rate consistent with a beta-adrenergic effect from systemic absorption of the epinephrine. An increase in systolic blood pressure independent of the use of epinephrine also occurs, but epinephrine appears to mitigate against an increase in diastolic blood pressure.

Non-deterministic individual responses to receptor-selective opioid agonists.

To assess within a single rat strain individual variability of analgesic responses to sub-ED50 doses of receptor-selective opioids, we measured: 1) tail flick latency (TFL) responses after intrathecal (ith) injection of delta, mu, and kappa agonists administered serially; 2) TFL and tail pinch latencies (TPch) after intravenous (iv) mu and kappa agonists; and 3) TFL and TPch after iv agonists of mu or combined mu + delta selectivity. Mean values in each study confirmed an analgesic response, but individual TFL and TPch responses were chaotic and, within each study, rank order correlations between TFL and TPch values within or between drugs were insignificant. Our results suggest a hypothesis that such responses are intrinsically nondeterministic because--resembling other complex dynamic systems--they are generated by stochastic receptor-transmitter interactions that in turn evoke a series of nonlinearly coupled cellular and neural events.