Age and obesity as risk factors in perioperative atrial fibrillation.
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Aged↗
Biomedical subjects
T Treasure
Publications and source records attributed to T Treasure.
Staphylococcus epidermidis as a cause of postoperative wound infection after cardiac surgery: assessment of pathogenicity by a wound-scoring method.
Wound infection after clean surgery prolongs hospital stay but the organism most commonly isolated from wound discharge, Staphylococcus epidermidis, is often dismissed as a contaminant or commensal. The wounds of 517 patients were assessed, after cardiac surgery, by a wound-scoring method ('ASEPSIS') and a close comparison was made of the appearance and clinical outcome of 89 wounds, from which bacteria were isolated. There was no significant difference in the scores of 49 wounds, where S. epidermidis was the sole isolate (9.5 per cent of all wounds, 95 per cent CI 6.9-12.0 per cent), and 13 wounds infected with Staphylococcus aureus (2.5 per cent, 95 per cent CI 1.2-3.9 per cent). Repeat cultures were obtained from 21 of the 49 wounds and, in 16 of these, the second isolate showed the same biochemical reactions and antibiotic resistance pattern as the first. Infection of sternal wounds is commoner with coagulase-negative staphylococci than with S. aureus and, clinically, is just as severe.
Cardiac Surgical Procedures↗
Hydroxyethyl starch: an alternative to plasma for postoperative volume expansion after cardiac surgery.
Hydroxyethyl starch (HES) is a recently developed synthetic volume expander. Forty patients undergoing coronary artery surgery were randomized to receive either HES or plasma protein fraction (PPF) as non-blood volume replacement according to standard haemodynamic criteria. The two groups were comparable in all respects. The median colloid use in the first 24 h was 950 ml (range 500-1500) in the HES group and 975 ml (350-2000) in the PPF group (not significant). There was no difference in blood use, urine output or blood loss between the two groups. Tests of coagulation showed the postoperative changes usual in cardiac surgical patients. There was no difference between the two groups in thrombin time, prothrombin time, activated partial thromboplastin time, or fibrinogen concentration. Similarly, tests of platelet function and Factor VIII and von Willebrand Factor activity showed no difference between the two groups. We conclude that HES is a safe and effective volume expander, and its relative lack of expense and ease of availability make its routine use after cardiac surgery an attractive proposition.
Adult↗
Contamination of blood during cardiopulmonary bypass: the effect of antibiotic prophylaxis.
Despite antibiotic prophylaxis in cardiac surgery, gram-positive bacteria can be isolated in up to 10% of intraoperative blood cultures. During a prospective randomized trial, blood was collected from the oxygenator at the end of bypass in 58 patients given teicoplanin and in 60 others given flucloxacillin and tobramycin. Coagulase-negative staphylococci were cultured from 16 patients given teicoplanin but in only four cases after flucloxacillin and tobramycin (Fisher's exact test, P = 0.005). In contrast, Propionibacterium spp. or coryneforms were isolated from 22 patients given flucloxacillin and tobramycin and from only one patient in the teicoplanin group. There were no cases of prosthetic valve endocarditis. After 3 h exposure to 4 x MIC of teicoplanin there was only a 10-60 fold reduction in cfus of Staphylococcus epidermidis, which may partly explain the excess of these organisms.
Anti-Bacterial Agents↗
Cerebral blood flow during cardiopulmonary bypass.
In a study of the cerebral consequences of cardiopulmonary bypass (CPB), we have assessed cerebral blood flow (CBF) by intra-arterial Xenon 133 clearance, utilising a Novocerebrograph 10a, before, during and immediately following CPB. All patients (n = 51), under the care of a single surgical team underwent elective coronary revascularisation using a standardised anaesthetic and surgical protocol. CBF, measured as the initial slope index (ISI), fell significantly from before (median 22.5) to on bypass (median 20) (Wilcoxon P less than 0.005) and was significantly increased in the immediate post-bypass period (median 28) compared with pre-bypass (Wilcoxon P less than 0.001). Scattergrams reveal CBF to be independent of arterial pressure (BP) but show an important relationship between arterial PaCO2 and CBF. The correlations between PaCO2 and CBF prior to bypass (r = 0.46 P less than 0.005) and post-bypass (r = 0.46 P less than 0.001) are very similar, whilst on bypass, the correlation, although remaining significant, is reduced (r = 0.31 P less than 0.02). The median values for arterial PaCO2 are low throughout the study (pre-bypass median 33 mmHg, on bypass median 28 mm Hg and post-bypass median 36 mm Hg). The maintenance of PaCO2 within the normal range of 35-45 mm Hg may minimise the risk of low CBF due to hypocarbia which could theoretically be harmful in patients known to be at risk of both short term and long term cerebral dysfunction.
Carbon Dioxide↗
Intraoperative assessment of myocardial revascularisation for the relief of ischaemia using monophasic action potential recordings.
We have been concerned with developing a method of assessing regional myocardial perfusion which is simple, quick and without hazard to the patient. Monophasic action potential (MAP) recordings provide a highly sensitive measure of localised myocardial ischaemia. We have developed a hand-held pressure contact silver/silver chloride electrode for recording MAP signals from the left ventricular epicardium. The design enables it to slide within the pericardium on the left ventricle/epicardium with minimal displacement of the heart. Three protocols were adopted providing different permutations of atrial pacing and graft occlusion. Protocol 1: after discontinuing bypass, atrial pacing was established. After 90 s, all grafts were occluded for a period of 90 s. Protocol 2: after discontinuing bypass, all grafts were occluded for 90 s in the absence of pacing. Protocol 3: atrial pacing was established for 60 s before grafting and bypass and repeated subsequent to grafting and discontinuing bypass. Our results show that the most promising method is protocol 3. The most important results were that when heart rate is taken into account, the ischaemic changes in the MAP were significantly less impressive (P less than 0.05) following grafting. With further refinement, this technique may be applicable to the assessment of individual grafts.
Action Potentials↗
Antibiotic prophylaxis in cardiac surgery: serum and tissue levels of teicoplanin, flucloxacillin and tobramycin.
In this study, the pharmacokinetics of teicoplanin have been studied in serum, fat and bone during and after cardiac surgery with two dose (400 and 200 mg) and three dose (400 mg each) regimens in a total of 49 patients. For comparison, 20 other patients, who had received a regimen of flucloxacillin (500 mg qds for five days) and tobramycin (1.5 mg/kg initially then 80 mg tds for three days), were similarly investigated. The lowest mean serum level of teicoplanin during operation was 6.9 mg/l in the two dose regimen and 9.7 mg/l with the three dose regimen. Mean serum levels of flucloxacillin and tobramycin fell to 7 and 1.4 mg/l respectively by the end of operation. At the end of bypass, fat washings contained a mean of 1.2 mg/l of teicoplanin and bone washings a mean of 6.3 mg/l. Mean tobramycin levels were 0.4 and 0.9 mg/l respectively and flucloxacillin less than 1 mg/l in washings from both tissues. The low levels of teicoplanin in fat may explain an excess of Gram-positive sternal infections in the accompanying clinical trial.
Anti-Bacterial Agents↗
Antibiotic prophylaxis in cardiac surgery: a prospective comparison of two dosage regimens of teicoplanin with a combination of flucloxacillin and tobramycin.
Teicoplanin, a new glycopeptide antibiotic, has a serum half-life of 47 h and excellent activity against Gram-positive bacteria, including methicillin resistant staphylococci, making it a potentially useful drug for cardiac surgical prophylaxis. In two prospective randomized studies, we have compared it with a broad spectrum regimen of an aminoglycoside and flucloxacillin. In the first trial, teicoplanin (400 mg on induction of anaesthesia and 200 mg 24 h later), was compared with tobramycin (80 mg tds for three days) and flucloxacillin (500 mg qds for 5 days) in 314 patients. Teicoplanin prophylaxis resulted in a significantly greater number of sternal wound infections (P less than 0.01), due to Gram-positive bacteria. Furthermore, Gram-negative bacteria were responsible for more respiratory and urinary infections after teicoplanin prophylaxis. In the second trial, comprising 203 patients, the teicoplanin dose regimen was changed to three doses of 400 mg but this did not improve the rates of infection.
Anti-Bacterial Agents↗
Demonstration of the ascending aorta in infective endocarditis by intravenous digital subtraction angiography.
Four patients with infective endocarditis were examined by digital subtraction angiography immediately before operation. In three a root abscess was suspected and the remaining patient was believed to have a false aneurysm at an infected aortic cannulation site. In all the cases digital subtraction angiography showed the structure in several projections and confirmed the presence of a cavity. Subsequent operation confirmed the site and nature of the lesions.
Adult↗
Balloon closure of a surgical aorto-atrial communication.
Surgical repair of an extensive dissection of the proximal aorta (Shumway type A or DeBakey type I) was complicated by persistent haemorrhage from the surgical suture lines and via the false lumen. This was controlled by closing the aortic adventitia round the repaired aorta and by creating an anastomosis between the subadventitial space and the right atrial appendage. Though the haemorrhage was contained, the left to right (aorto-atrial) shunt led to a severe low output state, which was corrected by percutaneous closure of the fistula with a detachable balloon. A year after operation computed axial tomographic scanning showed the balloon in place though the para-aortic space persisted and communicated freely with the aorta.
Aged↗
Hypothermic protection (26 degrees-25 degrees C) without perfusion cooling for surgery of congenital cardiac defects using prolonged occlusion.
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Heart Arrest, Induced↗
Monophasic action potentials at discontinuation of cardiopulmonary bypass: evidence for contraction-excitation feedback in man.
Mechanical dysfunction is the strongest predictor of sudden cardiac death due to arrhythmia. Contraction-excitation feedback whereby changes in myocardial length/tension influence the time course of repolarization and excitability would provide a possible mechanism. Such a relationship has been shown in animals but has yet to be demonstrated in man. A useful model for studying this relationship is provided by the process of weaning off cardiopulmonary bypass after routine coronary artery surgery. During this weaning period of approximately 1 min, the heart is converted from being partially empty and flaccid (i.e., a "nonworking" state) to being filled and stretched to support the circulation (i.e., a "working" state). Monophasic action potentials (MAPs) were recorded from the left ventricular epicardium as a measure of repolarization time in 16 patients at discontinuation of cardiopulmonary bypass. Systolic pressure was recorded from the radial artery line. Measurements were made at three stages that related to different dynamic states of the heart: (1) starting to come off bypass ("minimally working"), defined as the time of first appearance of an inflection on the arterial pressure trace indicating the start of left ventricular ejection and valve opening, when arterial pressures represent left ventricular pressure, (2) half off bypass ("partially working"), and (3) off bypass ("wholly working"). During the process of discontinuing bypass MAP duration shortened, while systolic pressure increased. MAP duration at 90% and 60% repolarization (MAP D90, MAP D60) decreased from 288.0 +/- 29.5 msec (mean +/- SEM) and 235.0 +/- 27.9 msec in the minimally working heart to 274.5 +/- 30.2 msec and 224.2 +/- 27.3 msec in the partially working heart (p less than .001), with a subsequent decrease to 261.0 +/- 28.8 and 214.0 +/- 28.7 when the heart was wholly working (p less than .001). Systolic pressure increased from 54.1 +/- 9.3 mm Hg in the minimally working heart to 65.9 +/- 13.8 mm Hg in the partially working heart (p less than .001) and subsequently increased to 75.5 +/- 13.3 mm Hg when the heart was wholly working (p less than .001). Mean heart rates did not change significantly. A strong correlation was obtained between absolute MAP duration and systolic pressure. Regression analysis revealed: MAP D90 vs systolic pressure (p less than .001) and MAP D60 vs systolic pressure (p less than .01).(ABSTRACT TRUNCATED AT 400 WORDS)
Action Potentials↗
Use of a glycopeptide antibiotic, teicoplanin, in the treatment of septicaemia caused by gram-positive bacteria.
Teicoplanin, a recently introduced glycopeptide antibiotic, has been used, in combination with other antibiotics, to treat 31 episodes of septicaemia caused by Gram-positive organisms. Teicoplanin has double the activity of vancomycin against many Gram-positive bacteria, but allergic reactions and toxicity appear to be infrequent. A single daily dose is sufficient to maintain therapeutic levels, which is an advantage in conditions requiring long-term treatment. Of the 31 episodes treated, 16 were associated with infective endocarditis, 11 with Hickman catheter infection, two with bone and joint infection, and two with infection of other indwelling prosthetic devices. Staphylococcus epidermidis was isolated in 18 infections, of which seven treatment courses were unsuccessful. One death occurred from an uncontrolled infection, three deaths from underlying disease (one of which had relapsed twice), and one after withdrawal of treatment following febrile reaction. Eleven episodes were cured. Six episodes of Staphylococcus aureus septicaemia were treated, of which two failed to respond, two relapsed, one improved and one was cured. The remaining seven episodes were caused by streptococci (including Streptococcus faecalis), and in all of them cure was achieved despite the lack of consistent serum bactericidal activity in vitro.
Adolescent↗
Should the temperature chart influence management in cardiac operations? Result of a prospective study in 314 patients.
The body temperature is measured routinely and carefully charted in our own and presumably all units. Pyrexia is normal after bypass and is discounted on the basis of clinical experience in the first few days. If this pyrexia persists, a search for infection may be instigated and discharge from the hospital may be delayed. A clinical trial of antibiotic prophylaxis provided the opportunity to collect and collate 6-hourly temperature observations for 314 patients for 1 week after operation. The length of bypass and the presence of lower respiratory tract infection were positively correlated with the duration of postoperative fever. However, neither surgical sepsis nor urinary tract infection had any consistent effect on the duration or magnitude of postoperative fever in the first week.
Anti-Bacterial Agents↗
Depression and outcome in acute myocardial infarction.
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Acute Disease↗
The effect of antibiotic prophylaxis and topical antiseptics on the bacterial flora of the skin after cardiac surgery.
A controlled trial of antibiotic prophylaxis in cardiac surgery compared a two-dose regimen of teicoplanin with a longer conventional course of flucloxacillin and tobramycin. In 12 patients the susceptibility of the bacterial skin flora of four different sites to each of the three antibiotics was determined and the results are reported here. Less than 1% of the Gram-positive colonies showed reduced sensitivity to teicoplanin (MIC greater than or equal to 4 mg l-1). Before operation, 99% inhibition of Gram-positive growth was achieved at 26 (54%) of 48 sites by 1 mg l-1 of flucloxacillin and 13 (27%) sites by 2 mg l-1 tobramycin. By the 7th day after operation there was a significant reduction in the number of sites showing similar sensitivity to flucloxacillin [16 (33%) sites, P less than 0.05]. The use of teicoplanin was not associated with the emergence of Gram-negative skin flora but tobramycin promoted acquisition of aminoglycoside-resistant strains.
Adult↗
Factors predisposing to wound infection in cardiac surgery. A prospective study of 517 patients.
Postoperative wound infection can greatly prolong hospital stay after cardiac surgery, so the identification of predisposing factors may help in prevention or early institution of treatment. Transfer of organisms from the leg to the sternum during coronary artery surgery has been proposed as a major additional cause of sepsis. The definition of wound infection is not standardised and therefore makes comparison between centres difficult. In a prospective study of 517 patients, a wound scoring method (ASEPSIS) has been used to register all abnormal wounds to maximise the chances of identifying factors predisposing to infection. Abnormal healing was noted in 99 (19%) sternal wounds and 29 (8%) leg wounds. Obesity was the principal risk factor (P less than 0.005). Diabetes, reoperation, length of preoperative hospital stay, age, sex, or previous cardiac surgery had little effect on wound healing. The range of bacteria isolated from chest wounds after coronary artery surgery was similar to that after valvular surgery, but the rate of isolation was significantly greater. With careful attention to technique, leg wound infection rarely presented a clinical problem and did not appear to be a source of bacteria infecting the chest wound.
Cardiac Surgical Procedures↗
Continuous display of plasma potassium during cardiac surgery.
We have evaluated the use of an intravascular ion-selective electrode for continuous plasma potassium monitoring in patients during and after cardiac surgery. Potassium estimations from the indwelling electrode provided a rapid and sensitive, but only moderately reliable, indicator of potassium as confirmed by blood samples. Several significant changes in the plasma potassium were found to occur in the period studied and using this continuous monitor, the precise time course of these changes was recorded.
Cardiac Surgical Procedures↗