Validation of the cognitive recovery assessments with the Postoperative Quality of Recovery Scale in patients with low-baseline cognition.

Patients with pre-surgery cognitive impairment cannot currently be assessed for cognitive recovery after surgery using the Postoperative Quality of Recovery Scale (PostopQRS), as they would mathematically be scored as recovered. We aimed to validate a novel method to score cognitive recovery in patients with low-baseline cognition, using the number of low-score tests rather than their numerical values. Face validity was demonstrated in 86 participants in whom both the Postoperative Quality of Recovery Scale and an 11-item neuropsychological battery were performed. The Postoperative Quality of Recovery Scale agreed with neuropsychological categorisation of low vs. normal cognition 74% of the time, with all but five incorrectly coded participants deviating by only one neurocognitive test. Cognitive recovery over time was comparable for groups with differing baseline cognitive function, irrespective of whether the Postoperative Quality of Recovery Scale or neuropsychological methods were used. Discriminant validation was demonstrated in a post-hoc analysis of the steroids in cardiac surgery substudy by allocating groups to normal (n = 246) or low-baseline cognition (n = 231) stratified by cognitive recovery on day 1. Recovery was similar for participants with low and normal baseline cognition. Postoperative length of stay was longer in patients with failed cognitive recovery whether they had normal mean (SD) (10.4 (10.0) vs. 8.0 (5.9) days, p = 0.02) or low-baseline cognition (12.0 (11.1) vs. 8.2 (4.7) days, p < 0.01). Overall quality, as well as cognitive, emotive and physiological recovery was independent of baseline cognition. The modified scoring method for the Postoperative Quality of Recovery Scale cognitive domain demonstrates acceptable face and discriminant validity.

Pilot multi-centre randomised trial of the impact of pre-operative focused cardiac ultrasound on mortality and morbidity in patients having surgery for femoral neck fractures (ECHONOF-2 pilot).

Hip fracture surgery is common, usually occurs in elderly patients who have multiple comorbidities, and is associated with high morbidity and mortality. Pre-operative focused cardiac ultrasound can alter diagnosis and management, but its impact on outcome remains uncertain. This pilot study assessed feasibility and group separation for a proposed large randomised clinical trial of the impact of pre-operative focused cardiac ultrasound on patient outcome after hip fracture surgery. Adult patients requiring hip fracture surgery in four teaching hospitals in Australia were randomly allocated to receive focused cardiac ultrasound before surgery or not. The primary composite outcome was any death, acute kidney injury, non-fatal myocardial infarction, cerebrovascular accident, pulmonary embolism or cardiopulmonary arrest within 30 days of surgery. Of the 175 patients screened, 100 were included as trial participants (screening:recruitment ratio 1.7:1), 49 in the ultrasound group and 51 as controls. There was one protocol failure among those recruited. The primary composite outcome occurred in seven of the ultrasound group patients and 12 of the control group patients (relative group separation 39%). Death, acute kidney injury and cerebrovascular accident were recorded, but no cases of myocardial infarction, pulmonary embolism or cardiopulmonary arrest ocurred. Focused cardiac ultrasound altered the management of 17 participants, suggesting an effect mechanism. This pilot study demonstrated that enrolment and the protocol are feasible, that the primary composite outcome is appropriate, and that there is a treatment effect favouring focused cardiac ultrasound - and therefore supports a large randomised clinical trial.

Focused echocardiography: a systematic review of diagnostic and clinical decision-making in anaesthesia and critical care.

Focused echocardiography is becoming a widely used tool to aid clinical assessment by anaesthetists and critical care physicians. At the present time, most physicians are not yet trained in focused echocardiography or believe that it may result in adverse outcomes by delaying, or otherwise interfering with, time-critical patient management. We performed a systematic review of electronic databases on the topic of focused echocardiography in anaesthesia and critical care. We found 18 full text articles, which consistently reported that focused echocardiography may be used to identify or exclude previously unrecognised or suspected cardiac abnormalities, resulting in frequent important changes to patient management. However, most of the articles were observational studies with inherent design flaws. Thirteen prospective studies, including two that measured patient outcome, were supportive of focused echocardiography, whereas five retrospective cohort studies, including three outcome studies, did not support focused echocardiography. There is an urgent requirement for randomised controlled trials.

Transthoracic and transoesophageal echocardiography: a systematic review of feasibility and impact on diagnosis, management and outcome after cardiac surgery.

Transthoracic and transoesophageal echocardiography are increasingly used as tools to improve clinical assessment following cardiac surgery. However, most physicians are not trained in echocardiography, and there is no widespread agreement on the feasibility, indications or effect on outcome of transthoracic or transoesophageal echocardiography for patients after cardiac surgery. We performed a systematic review of electronic databases for focused transthoracic and transoesophageal echocardiography after cardiac surgery which revealed 15 full-text articles. They consistently reported that echocardiography is feasible, whether performed by a novice or expert, and frequently resulted in important changes in diagnosis of cardiac abnormalities and their management. However, most were observational studies and there were no well-designed trials investigating the impact of echocardiography on outcome. We conclude that both transthoracic and transoesophageal echocardiography are useful following cardiac surgery.

The accuracy of transoesophageal echocardiography in estimating pulmonary capillary wedge pressure in anaesthetised patients.

The objective of this study was to identify whether pulmonary capillary wedge pressure can be estimated in anaesthetised patients receiving mechanical ventilation, using transoesophageal echocardiography. A retrospective validation study investigated a 10-patient cohort with variable haemodynamic conditions, and a 102-patient series in which a single measurement was made during stable haemodynamic conditions. Concurrent echocardiographic Doppler and pulmonary artery catheter wedge pressure measurements were performed. In the 10-patient cohort, the systolic fraction of Doppler measurements in the pulmonary vein (r = -0.32, p = 0.035) and the E/A ratio (r = 0.56, p = 0.0009) were correlated with the wedge pressure. In all cases, the limits of agreement exceeded 10 mmHg, and sensitivity or specificity for detecting wedge pressure ≥ 15 mmHg was poor. This study demonstrates proof of concept that using transoesophageal echocardiography for estimating the pulmonary artery wedge pressure may not be sufficiently accurate for clinical use.

The impact of focused transthoracic echocardiography in the pre-operative clinic.

Patients with suspected or symptomatic cardiac disease, associated with increased peri-operative risk, are often seen by anaesthetists in the pre-assessment clinic. The use of transthoracic echocardiography in this setting has not been reported. This prospective observational study investigated the effect of echocardiography on the anaesthetic management plan in 100 patients who were older than 65 years or had suspected cardiac disease. Echocardiography was performed by an anaesthetist, and was validated by a cardiologist. Overall, the anaesthetic plan was changed in 54 patients. Haemodynamically significant cardiac disease was revealed in 31 patients, resulting in a step-up of treatment in 20 patients, including: cardiology referral (four patients); altered surgical (two) and anaesthetic (four) technique; use of invasive monitoring (13); planned use of vasopressor infusion (10); and postoperative high dependency care (five). Reassuring negative findings in 69 patients led to a step-down in treatment in 34 patients: altered anaesthetic technique (six); procedure not cancelled (10); cardiology referral not made (10); use of invasive monitoring not required (seven); and high dependency care not booked (11). We conclude that focused transthoracic echocardiography in the pre-operative clinic is feasible and frequently alters management in patients with suspected cardiac disease.

The impact on cardiac diagnosis and mortality of focused transthoracic echocardiography in hip fracture surgery patients with increased risk of cardiac disease: a retrospective cohort study.

Hip fracture surgery is associated with a high rate of mortality and morbidity; heart disease is the leading cause and is often unrecognised and inadequately treated. Pre-operative focused transthoracic echocardiography by anaesthetists frequently influences management, but mortality outcome studies have not been performed to date. Mortality over the 12 months after hip fracture surgery, in 64 patients at risk of cardiac disease who received pre-operative echocardiography, was compared with 66 randomised historical controls who did not receive echocardiography. Mortality was lower in the group that received echocardiography over the 30 days (4.7% vs 15.2%, log rank p=0.047) and 12 months after surgery (17.1% vs 33.3%, log rank p=0.031). Hazard of death was also reduced with pre-operative echocardiography over 12 months after adjustment for known risk factors (hazard ratio 0.41, 95% CI 0.2-0.85, p=0.016). Pre-operative echocardiography was not associated with a delay in surgery. These data support a randomised controlled trial to confirm these findings.

The impact of pre-operative focused transthoracic echocardiography in emergency non-cardiac surgery patients with known or risk of cardiac disease.

This prospective observational study investigated the effect of focused transthoracic echocardiography in 99 patients who had suspected cardiac disease or were ≥ 65 years old, and were scheduled for emergency non-cardiac surgery. The treating anaesthetist completed a diagnosis and management plan before and after transthoracic echocardiography, which was performed by an independent operator. Clinical examination rated cardiac disease present in 75%; the remainder were asymptomatic. The cardiac diagnosis was changed in 67% and the management plan in 44% of patients after echocardiography. Cardiac disease was identified by echocardiography in 64% of patients, which led to a step-up of treatment in 36% (4% delay for cardiology referral, 2% altered surgery, 4% intensive care and 26% intra-operative haemodynamic management changes). Absence of cardiac disease in 36% resulted in a step-down of treatment in 8% (no referral 3%, intensive care 1% or haemodynamic treatment 4%). Pre-operative focused transthoracic echocardiography in patients admitted for emergency surgery and with known cardiac disease or suspected to be at risk of cardiac disease frequently alters diagnosis and management.

The influence of propofol or desflurane on postoperative cognitive dysfunction in patients undergoing coronary artery bypass surgery.

We investigated the influence of either propofol or desflurane on the incidence of postoperative cognitive dysfunction in a randomised trial of 180 patients undergoing coronary artery bypass surgery. The primary outcome was incidence of postoperative cognitive dysfunction at 3 months, defined as ≥1 SD deterioration in two or more of 12 neurocognitive tests. Secondary outcomes included early postoperative cognitive dysfunction (between days three and seven), delirium on day one, morbidity and length of hospital stay. Early postoperative cognitive dysfunction was significantly higher with propofol compared with desflurane (56/84 (67.5%) vs 41/83 (49.4%), respectively, p=0.018), but this effect was not seen at 3 months (10/87 (11.2%) vs 9/90 (10.0%), respectively. There was no difference in delirium (7/89 (7.9%) vs 12/91 (13.2%), respectively, length of hospital stay (median (IQR [range]) 7 (6-9 [4-15]) vs 6 (5-7 [5-16) days, respectively or other morbidities. Desflurane was associated with reduced early cognitive dysfunction.

Functional comparison of anaesthetic agents during myocardial ischaemia-reperfusion using pressure-volume loops.

BACKGROUND: Left ventricular (LV) pressure-volume (PV) loops were used to compare the functional effects that accompany the cardioprotection seen with desflurane, sevoflurane, and propofol in a rabbit preparation of coronary ischaemia-reperfusion (IR). METHODS: Male New Zealand White rabbits (n=48) were anaesthetized with propofol (70 mg kg(-1) h(-1)), desflurane (8.9%), or sevoflurane (3.8%) and randomized to receive IR or non-ischaemic time-matched (TC) perfusion protocol. IR groups (desIR, propIR, and sevIR) underwent 30 min of left anterior descending coronary artery occlusion and then 120 min of reperfusion. TC groups (desTC, propTC, and sevTC) were anaesthetized for 150 min without ischaemia. Haemodynamic endpoints included mean arterial pressure, heart rate, cardiac index, systemic vascular resistance index, preload-recruitable stroke-work, time constant of relaxation (tau), and end-diastolic PV relationship (EDPVR). Ventricles in the IR groups were excised and stained with 2,3,5-triphenyl-tetrazolium chloride in order to measure infarct size. RESULTS: Myocardial infarction size was greater in the propIR group [35.74 (sd 11.32)%] compared with the desIR [13.44 (3.09)%] and sevIR [17.96 (6.63)%] groups (P<0.001). EDPVR deteriorated in the sevIR and propIR groups compared with their TC groups, sevTC (P=0.03) and propTC (P=0.044), respectively. There was no difference in any haemodynamic endpoints for the desIR group compared with its TC control (desTC). CONCLUSIONS: During ischaemia, all anaesthetics provide haemodynamic stability and preservation of LV contractility, whereas propofol and sevoflurane, but not desflurane, caused increased LV diastolic stiffness. Desflurane and sevoflurane provide superior cardioprotection compared with propofol.

Total arterial coronary revascularization: techniques and results in 3,220 patients.

BACKGROUND: To overcome the problems of late vein graft atherosclerosis, occlusion and need of coronary reoperations, we have adopted a strategy of total arterial coronary revascularization. We evaluated our experience with this strategy to establish its safety and efficacy. METHODS: All 3,220 consecutive patients who had total arterial coronary revascularization from January 1988 to June 1998 were evaluated. Data were collected prospectively. The mean age was 62.2 years. Of the patients, 595 (18.8%) had diabetes; 739 (23%) had a left ventricular ejection fraction of less than 0.50; and 484 (15%) were classified unstable/urgent. The conduits included 3,140 left internal thoracic arteries, 1,224 right internal thoracic arteries, and 2,417 radial arteries, 654 of which were bilateral. A Y or T graft with the left internal thoracic artery was used in 467 patients. Patients were followed up at 1 month, 3 months, and yearly thereafter. Postoperative angiography was performed for symptoms or as part of an ethics committee-approved prospective study. RESULTS: The operative mortality rate was 0.7% (21 patients). Complications included stroke in 26 patients (0.8%), myocardial infarction in 27 (0.8%), sternal infection in 35 (1.1%), and reoperation for hemorrhage in 23 (0.7%). The peak level of the myocardial enzyme of creatine kinase was 16.4+/-14.9 IU/L. Twenty-five patients (0.8%) required intraoperative or postoperative intraaortic balloon pump support. Mortality and stroke rates were higher in patients having reoperation (0.6% versus 1.8%; p = 0.11; and 0.7% versus 2.2%; p = 0.07, respectively). Postoperative angiographic patency was 97% at 5 years for the left internal thoracic artery (620 grafts), 89% at 5 years for the right internal thoracic artery (276 grafts), and 91% at 1 year for the radial artery (65 grafts). CONCLUSIONS: Total arterial coronary revascularization can be performed safely with good patency rates in a large number of patients and may potentially avoid the sequelae of vein graft atherosclerosis.

Exclusive Y graft operation for multivessel coronary revascularization.

BACKGROUND: The pedicled (in-situ) left internal mammary artery grafted to the left anterior descending artery has a very high late patency and reduces late mortality following coronary artery bypass surgery. A technique is described which achieves total arterial revascularization in patients with multivessel coronary disease and which is also entirely pedicled. METHODS: Using the left internal mammary artery and radial artery joined as a composite Y graft, all coronary territories may be grafted. RESULTS: One in-hospital death from 464 patients (0.2%) occurred. Age (mean +/- standard error) was 64.7 +/- 0.5 years and number of distal anastomoses 3.4 +/- 0.04. Of 1,681 patients from Royal Melbourne Hospital, 346 had this operation. Comparison found no preoperative selection bias and no postoperative differences in complications. Actuarial survival was 0.98 +/- 0.01 at 36.1 +/- 0.3 months. CONCLUSIONS: Total arterial revascularization may be performed using the left internal mammary artery and radial artery as a composite Y graft. There was no increase in complications. This technique preserves the left internal mammary artery to left anterior descending artery graft.

Routine immediate extubation after cardiac operation: a review of our first 100 patients.

BACKGROUND: Early extubation after cardiac operation is an important aspect of fast-track cardiac anesthesia. Immediate extubation is an extension of this concept. We describe a technique that allows immediate extubation in the majority of patients. METHODS: To allow rapid emergence, anesthesia was modified from a high-dose opioid technique to intravenous propofol anesthesia supplemented with sevoflurane. Normothermic cardiopulmonary bypass was used with routine intermittent antegrade and retrograde tepid blood cardioplegia. High thoracic epidural analgesia was used to facilitate immediate extubation in the majority of patients. Contraindications to immediate extubation were prolonged cardiopulmonary bypass (CPB) (>2.5 hours), hemodynamic instability, uncontrolled bleeding, morbid obesity, severe pulmonary hypertension, congestive cardiac failure, or if the operation was emergent. RESULTS: Of 109 consecutive patients, 100 were immediately extubated (92%). No patient required reintubation within the first 24 hours after operation. One patient required reintubation 3 days after operation for sputum retention, and 2 patients required reoperation. There was no mortality and the incidence of perioperative morbidity was low. CONCLUSIONS: Immediate extubation after cardiac operation can be safely achieved and is possible in a majority of patients.

Blood flow in composite arterial grafts and effect of native coronary flow.

BACKGROUND: Total arterial coronary revascularization can be achieved by joining arteries together as a composite graft with the proximal left internal mammary artery as the only source of blood inflow. Proof of the capacity of this composite conduit to provide adequate blood flow to the coronary circulation is required. METHODS: The radial artery was anastomosed to the left internal mammary artery as a Y graft in 17 patients and all coronary arteries grafted. Intraoperative blood flow through the composite grafts was evaluated by the transit-time Doppler technique. RESULTS: Against no resistance, blood flow in the left internal mammary artery alone was 99 +/- 9 mL/min and rose to 173 +/- 16 mL/min when the radial artery was anastomosed as a Y graft. Composite-graft flow following grafting was 88 +/- 9 mL/min, 49 +/- 6 mL/min when the aortic clamp was removed and native coronary flow restored and 82 +/- 13 mL/min following weaning from cardiopulmonary bypass. The maximal potential flow through the composite graft was 2.3-fold (95% CI 1.6 to 3.2) greater than that after cardiopulmonary bypass. CONCLUSIONS: Total arterial revascularization, using a composite graft, provided a 2.3-fold reserve of blood flow to the coronary vascular bed through the grafts.

Reduced neuropsychological dysfunction using epiaortic echocardiography and the exclusive Y graft.

BACKGROUND: To examine the effect of screening the aorta for atheroma before aortic manipulation and use of exclusive Y graft revascularization on the incidence of neuropsychological dysfunction after coronary artery bypass. METHODS: Aortic atheroma was detected using epiaortic and transesophageal echocardiography. Atheroma avoidance was facilitated by use of the exclusive Y graft technique, which has no aortic coronary anastomoses. In the control group aortic atheroma was assessed by manual palpation, and we attempted to avoid any atheroma detected. In this group we also used aorta-coronary grafts. Transcranial Doppler imaging of the right middle cerebral artery was used to detect cerebral microemboli. Neuropsychological dysfunction was defined as a 20% or more decline in score for at least 20% of a neuropsychometric battery of ten tests for each patient. RESULTS: Late dysfunction at 57 +/- 2 days postoperatively in the control group was 38.1% and in the echo/Y group was 3.8% (p' = 0.012). Microemboli detected by transcranial Doppler imaging during periods of aortic manipulation was greater for those with late dysfunction (5.2 +/- 3.0 compared with 0.5 +/- 0.2) (p' = 0.018). No clinical strokes occurred in either group. CONCLUSIONS: The combined techniques of epiaortic screening and exclusive Y graft for coronary artery bypass operations resulted in a low incidence of late neuropsychological dysfunction.

Total arterial coronary revascularization and factors influencing in-hospital mortality.

OBJECTIVE: To determine if arterial conduit selection or more efficient arterial revascularization techniques influence in-hospital mortality. METHODS: Data from patients undergoing coronary artery bypass surgery at Royal Melbourne Hospital, Australia, between 1 January 1996 and 30 June 1998 (n = 1681) was collected prospectively. Logistic regression analysis was performed. RESULTS: Independent preoperative predictors of increased in-hospital mortality included renal failure, redo coronary artery surgery and intra-aortic balloon pump use. In-hospital mortality for total arterial revascularization 0.7%, radial artery use 0.9%, pedicled arterial revascularization 0.2%, composite arterial conduit 0.4%, and the exclusive Y graft operation 0.3%. These were all associated with reduced in-hospital mortality. Mortality when vein graft was used was 2.9%. Most patients received total arterial revascularization, which was considered the primary surgical strategy. CONCLUSION: Total arterial revascularization, radial artery use and complex arterial reconstructions were associated with reduced in-hospital mortality. Preoperative renal failure, intra-aortic balloon pump use and redo coronary surgery predicted greater in-hospital mortality.

Radial artery harvest technique, use and functional outcome.

OBJECTIVE: To develop a simple harvest technique for radial artery (RA). To investigate the morbidity and functional outcome of RA harvest. METHODS: The neurovascular fascia surrounding the RA is divided. Only loose areolar tissue surrounds this artery making harvest of RA simple and allowing minimal trauma to the RA and surrounding muscles. Topical and intraluminal vasodilators but no systemic vasodilators are used. RESULTS: RA harvest commenced in December 1994. Between 1996 and 30 June 1998, 2167 RA were harvested and used to construct 3105 coronary anastomoses. A dramatic rise in RA use occurred during 1996. More than 80% of patients undergoing coronary artery bypass surgery (CABG) have RA harvested since this time. Total arterial revascularization rate also rose dramatically and is currently 80% of all CABG. This rate has been assisted by a rapid rise in the use of composite arterial grafting where aortic anastomoses can be avoided and currently represents 40% of all CABG. Hand strength was tested in 328 non-selected patients and was not reduced by RA harvest when hand dominance was taken into account. Objective sensation loss was present in 0.3% for the superficial radial nerve and 2.1% for the lateral cutaneous nerve of forearm. Pulse oximetry observations detected statistically significant but clinically irrelevant differences. Scar hypersensitivity occurred in 20%. Only two patients of all patients undergoing RA harvest reported late hand ischaemia. CONCLUSIONS: Harvest of the RA within the neurovascular plane is simple and associated with low morbidity.

Postoperative radial artery angiography for coronary artery bypass surgery.

OBJECTIVE: To compare radial artery (RA) patency with internal mammary artery (IMA) patency for coronary artery bypass surgery in our early experience. METHODS: Symptomatic as well as asymptomatic patients with > or =1 RA coronary graft underwent postoperative angiography. Each anastomosis was considered separately. A string sign referred to a diffusely narrowed conduit, which did not fill the grafted coronary artery, as well as all occluded conduits. The raw value of P was adjusted for the testing of multiple hypotheses (P'). The patency data for each conduit was divided into two parts. 'Cut-off' stenosis for a conduit was the lowest dividing coronary stenosis at which a difference in patency rate with P< or =0.05 occurred. RESULTS: One-hundred-and-twenty-nine patients had 137 radial arteries and 157 angiograms. Only the most recent angiogram was analyzed for each patient at 13+/-0.7 months (n=129). Overall patency for arterial conduit 91% (n=404) was not different from venous conduit 91% (n=42) and patency for RA 90% (n=226) was not different from IMA 92% (n=178), (P'=0.999). Cut-off stenosis for RA was 70% and IMA was 40%. Patent arterial conduit had a mean coronary stenosis of 85% and non-patent conduit 64%, (P'<0.001). Right coronary territory patency was 82 vs. 94% for other territories (P'=0.022). No overall differences in patency were noted for patients with sequential anastomoses, symptoms or coronary disease at the anastomosis at the time of surgery. Reversible ischaemia was detected in the distribution of only two of 14 string signs in patients undergoing sestamibi exercise protocol following angiogram. CONCLUSION: There were no differences in patency between radial artery and internal mammary artery at 13 months post-operative. Lower coronary stenosis and right coronary territory predicted lower patency. The clinical importance of a string sign remains to be determined.

Aortic valve area: measurement by transesophageal echocardiography and prediction by left ventricular outflow tract area.

We compared three techniques of aortic valve area (AVA) measurement using transesophageal echocardiography (TEE) and determined if AVA can be predicted from simple patient or echocardiographic measurements. AVA was simultaneously measured with direct planimetry, the continuity equation and with a novel technique combining stroke volume using thermodilution and continuous wave Doppler. Using planimetry as the reference in patients with normal valves, left ventricular outflow tract area (LVOTA), lean body mass (LBM), body surface area (BSA) and height were assessed as predictors of AVA. All three methods of AVA measurement showed close agreement and can be used interchangeably. Both LVOTA and LBM were predictors of AVA, but LVOTA was better. BSA and height were not acceptable as predictors of AVA. TEE can be used to measure AVA either with planimetry, the continuity equation, or in combination with thermodilution. LVOTA was the best predictor of AVA.