Is postspinal hypotension a sign of impaired cardiac performance in the elderly? An observational mechanistic study

Background

We have previously reported that stroke volume is reduced in a majority of elderly patients undergoing surgical repair of hip fracture before and after intrathecal injection of anaesthetic. We aimed to investigate these observations further in a prospective study of elderly patients undergoing elective hip or knee arthroplasty under spinal anaesthesia.

Methods

Patients ≥65 yr undergoing elective arthroplasty were monitored with LiDCOplus™ preoperatively (baseline), before and continuously for 45 min after spinal anaesthesia. Postspinal hypotension was defined as systolic blood pressure (bp) < 100 mm Hg or > 30% decrease from baseline. Associations between post-spinal hypotension and haemodynamic changes before (i.e. between baseline and before injection) spinal anaesthesia were analysed by logistic regression analysis.

Results

Twenty patients with a mean age of 74 (range 66-89) yr were included. Stroke volume index decreased by 14% (95% CI 9.3%-19%) before spinal anaesthesia. When patients were categorised according to post-spinal hypotension (Y/N) the patterns of haemodynamic changes differed. In the hypotensive patients, cardiac index progressively decreased whereas it increased initially in the non-hypotensive patients. Reduction of cardiac index from baseline before spinal anaesthesia was associated with increased risk of hypotension: OR 0.79 (95% CI 0.60, 0.91). The predictive value of reduced cardiac index was good (AUC under ROC curve 0.91).

Conclusions

A decrease in cardiac output from baseline before spinal anaesthesia and an inability to increase it after induction may be important features of postspinal hypotension in elderly patients.

[Interobserver variability study for daily cone beam computed tomography registration of prostate volumetric modulated arc therapy]

PURPOSE

This work evaluated the interobserver variability in cone beam computed tomography (CBCT) registration for prostate cancers treated with intensity-modulated radiotherapy.

MATERIAL AND METHODS

Twelve technologists realized 286 CBCT/CT registrations (bone registration followed by prostate to prostate registration). The registration results were compared to those obtained by two radiation oncologists (reference). Each technologist reported the shifts calculated by the software in all three axes. A statistical analysis allowed us to calculate the minimum threshold under which 95% of the observers found similar values. A variance analysis followed by the post hoc test were used to find differences in interobserver registration variability and determine whether any individual users performed registrations which differed significantly from those of the other users.

RESULTS

The registration differences compared to the reference in the three directions in terms of 95th percentile are: 2.1mm left-right, 3.5mm target-gun, 7.3mm anterior-posterior. In the posterior direction, 4% of the observers have found differences superior to 8mm, margin used in routine without the use of a daily CBCT. The variance test revealed a P-value <0.05 only for target-gun and for all observers there was no significant difference compared to the reference.

CONCLUSION

This study confirmed the interest of a 3D tissue registration for prostate treatments. The registration study showed a good interobserver reproducibility. This showed the importance of a daily CBCT/CT registration in prostate treatment with the possibility of a planning target volume margin reduction in the three directions. An evaluation of a partial delegation of registration to technologists should be done by the radiation oncologists.

Could benefits of epidural analgesia following oesophagectomy be measured by perceived perioperative patient workload?

BACKGROUND

A controversy exists whether beneficial analgesic effects of epidural analgesia over intravenous analgesia influence the rate of post-operative complications and the length of hospital stay. There is some evidence that favours epidural analgesia following major surgery in high-risk patients. However, there is a controversy as to whether epidural analgesia reduces the intensive care resources following major surgery. In this study, we aimed at comparing the post-operative costs of intensive care in patients receiving epidural or intravenous analgesia.

METHODS

Clinical data and rates of post-operative complications were extracted from a previously reported trial following thoraco-abdominal oesophagectomy. Cost data for individual patients included in that trial were retrospectively obtained from administrative records. Two separate phases were defined: costs of pain treatment and the direct cost of intensive care.

RESULTS

Higher calculated costs of epidural vs. intravenous pain treatment, 1,037 vs. 410 Euros / patient, were outweighed by lower post-operative costs of intensive care 5,571 vs. 7,921 Euros / patient (NS).

CONCLUSION

Higher costs and better analgesic effects of epidural analgesia compared with intravenous analgesia do not reduce total costs for post-operative care following major surgery.

Evaluation of costs and effects of epidural analgesia and patient-controlled intravenous analgesia after major abdominal surgery

BACKGROUND

The outcome of different treatment strategies for postoperative pain has been an issue of controversy. Apart from efficacy and effectiveness a policy decision should also consider cost-effectiveness. Since economic analyses on postoperative pain treatment are rare we developed a decision model in a pilot cost-effectiveness analysis (CEA) comparing epidural analgesia (EDA) and patient-controlled intravenous analgesia (PCIA) after major abdominal surgery in routine care.

METHODS

Using a decision-tree model, treatment with EDA (ropivacaine and morphine) was compared with PCIA (morphine). Effects and costs of treatment were established. The number of pain-free days at rest (pain intensity <30 using visual analogue scale 1-100 mm) was the primary measure of effect. An incremental cost-effectiveness ratio (ICER) was calculated as the difference in direct costs divided by the difference in effect. A database on 644 patients collected for the purpose of quality control during the period of 1997 to 1999 was the main data source. Sensitivity analysis was used to test uncertain data.

RESULTS

EDA was more effective in terms of pain-free days but more expensive. The additional cost for each pain-free day was 5652 Euros.

CONCLUSION

It is a judgement of value if the additional cost is reasonable. When the cost of around 55,000 Euros per gained life-year with full health for other interventions is debated, our result indicates poor cost-effectiveness for EDA. Before any conclusion can be drawn concerning policy recommendations the difference in costs has to be related to other outcome measures as length of hospital stay, morbidity and mortality are required.

[Biventicular pacing in patients with severe heart failure]

According to initial clinical results biventricular pacing seems to be effective in the treatment of patients suffering from drug refractory severe heart failure combined with intraventricular conduction disturbance. Biventricular cardioverter defibrillators and biventricular pacemakers were implanted in patients suffering from drug refractory severe heart failure in 3 and in 2 cases, respectively (follow up > 6 months). NYHA III-IV functional class, low left ventricular ejection fraction (23.2 +/- 5.4%), wide QRS (> 150 ms) with left bundle branch block and lateral dyssynchrony were present in each case. The left ventricle was enlarged in each patient (end-diastolic/end-systolic diameter: 78.6 +/- 9.2/66.2 +/- 8.1 mm). The indications of cardioverter defibrillator implantations were both sustained ventricular tachycardia and ventricular fibrillation, nonsustained ventricular tachycardia combined with syncope in 2 and in 1 case, respectively. The duration of QRS decreased (190 +/- 36 vs. 134 +/- 17 ms, p = 0.012) and wall movement disorder disappeared. At the last follow up every patients were in NYHA II functional class and a decrease in left ventricular diameter could be observed (end-diastolic: 72 +/- 10.4 mm, p = 0.07; end-systolic: 62 +/- 10 mm, p = 0.09). During the follow up period (7.3 +/- 1.7 months) 18 episodes of ventricular arrhythmias could be detected in the same patient. Biventricular pacemakers and cardioverter defibrillators were implanted and applied successfully in the treatment of congestive heart failure for the first time in Hungary. The effect of biventricular pacing on morbidity and mortality, the cost-effectiveness, the exact indication and the combined use with cardioverter defibrillator have yet to be proven in future randomized trials.

[Multichamber pacing--a new non-pharmacologic method for the treatment of severe heart failure]

According to initial clinical results biventricular pacing seems to be effective in the treatment of patients suffering from drug refractory severe heart failure combined with intraventricular conduction disturbance. Biventricular cardioverter defibrillators and biventricular pacemakers were implanted in patients suffering from drug refractory severe heart failure in 10 and in 15 cases, respectively. NYHA III-IV functional class, low left ventricular ejection fraction (24.2 +/- 6%), wide QRS (> 150 ms) with left bundle branch block and lateral dyssynchrony were present in each case. The left ventricle was enlarged in each patient (endodiastolic/endsystolic diameter: 78.6 +/- 9.2/68.2 +/- 8.3). The indications of cardioverter defibrillator implantations were both sustained ventricular tachycardia and ventricular fibrillation, nonsustained ventricular tachycardia combined with syncope in 7 and in 3 case, respectively. The duration of QRS decreased (187 +/- 32 vs. 136 +/- 19 ms, p = 0.012) and wall movement disorder disappeared. At the last follow up every patients were in NYHA II functional class and a decrease in left ventricular diameter could be observed (endodiastolic: 70.3 +/- 9.1 mm, p = 0.04; endosystolic: 61.9 +/- 8.8 mm, p = 0.04). During the follow up period (8.8 +/- 5.1 months) 18 episodes of ventricular arrhythmias were detected in the same patient, 2 patients died (1 arrhythmia death, 1 sudden cardiac death). Biventricular pacemakers and cardioverter defibrillators were implanted and applied successfully in the treatment of congestive heart failure for the first time in Hungary.

[Experience with surgical treatment of prosthetic valve endocarditis]

Prosthetic valve endocarditis (PVE) is a rare but dangerous complication that may occur after the implantation. The authors retrospectively summarize their 11-year experience in treating PVE. 2357 prosthetic valve (PV) implantations were performed over 11 years at the Department of Cardiovascular Surgery, Semmelweis University, Budapest, PVE was found to be the indication for operation in 1.8% of the cases (43/2357). 43 surgical interventions were carried out on 38 patients (mean age: 52.5 yrs, male/female ratio: 25/13). Blood cultures were positive in 86% and negative in 14% of the cases. The infected PV-s were replaced emergently (14%), urgently (79%) or electively (7%). The explanted valves were aortic in 55% and mitral 45% of the cases, 63% were mechanical and 37% biological. PVE followed the primary PV implantation in less than a year in 39.5%. Infected environment during the primary PV implantation was found to be a predisposing factor for the late endocarditis episodes. The mean age of the infected and explanted aortic bioprosthetic valves was significantly higher than that of explanted mechanical valves (p < 0.05). No such difference could be found at the mitral valves. The explanted valves were replaced by mechanical (75.5%) or biological (22.5%) devices. Homograft was implanted once. Early postoperative mortality of the primary PV replacements was 10.5%) devices. Homograft was implanted once. Early postoperative mortality of the primary PV replacements was 10.5%. Endocarditis reoccurred in 20% of the cases. Means follow-up duration was 45.5 months. Two-, five- an 10-year survival were 75%, 64% and 51% respectively. In conclusion in the surgical treatment of PVE, bioprosthetic and mechanical valves are suitable alternatives as opposed to homografts and freestyle stentless valves.

Neuroprotective effect of GYKI 52466 on AMPA-induced neurotoxicity in rat striatum

The neuroprotective effect of intraperitonally administered GYKI 52466 (2,3-benzodiazepine derivate) was investigated on AMPA (alpha-amino-3-hydroxy-5-methyl-4-isoxalon-propionic acid)-induced neuronal degeneration in the striatum of adult rats. The dose-dependent neurotoxic effect of AMPA was evaluated by the decrease in the activity of choline acetyltransferase (ChAT), due to degeneration of cholinergic neurons. An injection of 25 mg/kg GYKI 52466 30 min prior to the striatal application of 50 nmol AMPA, followed by repeated application of GYKI 52466 (10 times 5 mg/kg at 10 min intervals, reaching a final dose of 75 mg/kg) was able to prevent neuronal damage monitored by ChAT activity. Conversely, co-injection of GYKI 52466 (50 and 75 mg/kg) with AMPA (50 and 100 nmol) did not elicit any significant protection against the neuronal loss as measured by the ChAT enzyme activity. Therefore, one dose of agonist decreasing ChAT activity by about 40% (50 nmol) was tested on [3H]girisopam binding sites and on the immunoreactivity of glial fibrillary acid protein. The lesions were measured on methylene blue-stained serial sections with a computer assisted image analysis program (NIH Image 1.60). As a result of the AMPA treatment [3H]girisopam binding sites became depleted, and the immunoreactivity of glial fibrillary acid protein increased and on the site of the injection in the striatum a lesion developed. In the presence of AMPA (50 nmol) administered intrastriatally, GYKI 52466 (75 mg/kg i.p.) was able to make the radioactive signal of [3H]girisopam reappear. The volume of AMPA induced neuronal damage in the striatum and the extent of gliosis was reduced. These data provide evidence for the neuroprotective effect of GYKI 52466, and suggest a potential therapeutic value in some neurological disorders.

Sonochemical and thermal redox reactions of triphenylmethane and triphenylmethyl carbinol in nitrobenzene

The reaction of triphenylmethane and triphenylcarbinol with nitrobenzene under thermal or ultrasonic activation was studied. It was shown beyond doubt that the thermal reaction of the aforementioned systems at 210 degrees C occurs through electron transfer. The sonochemical reactions occur at 40 degrees C, although slowly, while heating at the same temperature leaves the system unchanged. Electron transfers are also involved but an unexpected reductive process was evident.

[Total proximal reconstruction of chronic aortic dissection in patients with Marfan syndrome]

Authors present two patients suffering from Marfan syndrome. Asymptomatically developed serious cardiovascular complications being characteristic of the syndrome itself were revealed at both cases. Type "A" aortic dissection was found at the first, and type "B" aortic dissection involving even the arch as well revealed at the other patient. They were operated on an elective base. Total proximal aortic reconstructions (aortic root-ascending aorta-arch) were performed under deep hypothermia using total circulatory arrest (35 and 87 min). Both patients are doing well without complaints 3-4 months following the surgical interventions. Control angiographic imagination has found normal anatomic conditions at one of the patients. Anastomosis stenosis at the borderline of the arch and descending aorta was revealed at the other case which should be necessary to operate at an later occasion.

Early and late hormonal modulation of cholinergic maturation in culture of embryonic mesencephali

Dissociated cells from 13- and 17-day-old embryonic rat mesencephali have grown in primary cultures in order to compare the early and late influences of different agents--insulin, dexamethasone and nerve growth factor (NGF)--on the expression of cholinergic maturation process. We have studied cholin acetyltransferase (ChAT) activity, which is regarded as a specific marker for cholinergic function of the brain, and a widely used differentiation marker, the acetyl-cholinesterase (AchE) enzyme. Biochemical maturation of increasing specific activity of ChAT in both younger and older cells was taken into consideration. During cultivation the AchE activity was slightly increased in younger cells, but a dramatic decrease could be noted in older ones. Insulin in concentration from 10 to 27 micrograms mL-1 causes a significant inhibition in ChAT activity in comparison with the enzyme activity measured in control cultures (insulin ranging from 1 to 100 ng), independently of embryos age. This polypeptide hormone is able to enhance AchE activity in the cultured cells, especially in older ones. With continuous treatment of the culture with dexamethasone, a synthetic glucocorticoid, the ChAT activity in younger cells reaches a maximum curve by day 9 (nine). At this time the AchE activity shows a slighter, no significant increase than at any other time during cultivation. In cell cultures taken from 17-day-old embryos however dexamethasone treatment evoked a significant decrease in ChAT activity with a concomitant increase of AchE activity which was compared to insulin treatment. In spite of the fact that the NGF is able to enhance the ChAT activity, no significant alteration in AchE activity can be measured in younger cell cultures. These results suggest an uneven expression of the enzymes in embryonic rat mesencephali in the presence of above agents depending on the age of cells.

[Experience with the surgical management of constrictive pericarditis]

61 patients were operated on for constrictive pericarditis at the Cardiovascular Surgical Clinic of Semmelweis Medical University in the last 33 years. The average hospital mortality of the surgical pericardiectomy was 4.9%. The final conclusions of this retrospective and follow up study are as follows: pericardiectomy is the method of choice in the treatment of constrictive pericarditis, since it does not has any therapeutic alternative, its hospital mortality is low and it results excellent early and late postoperative functional effects.

Molecular form of human lymphocyte membrane-bound acetylcholinesterase

The membrane-bound acetylcholinesterase (AchE) from human peripheral blood lymphocyte gives only one symmetrical peak on sucrose density gradient centrifugation in the presence of Triton X-100 detergent, with the calculated sedimentation coefficient of 6.5 S. However, this dimeric form of AchE was converted to a monomeric 3.8 S form when treated with 2-mercaptoethanol and iodoacetic acid. The results are consistent with studies which have shown by sodium dodecyl sulfate gel electrophoresis that the enzyme is built up of two identical monomers inter-linked by disulfide bond(s). Under reducing conditions, revealed a single species of 70,000 molecular weight, whereas under non-reducing conditions, another species of 140,000 molecular weight of the AchE was found. Polyacrylamide gel electrophoresis indicated a single band with AchE activity in the presence of Triton X-100. In contrast, in the absence of the same detergent multiple band pattern could be observed. These results suggest that membrane-bound AchE enzyme is present in homogenous dimeric form on human lymphocyte membrane.

Altered lymphocyte acetylcholinesterase activity in patients with senile dementia

Reductions in the acetylcholinesterase (AChE) activity of certain brain areas in patients with senile dementia of Alzheimer type (SDAT) have been found to correlate with the severity of the disease, suggesting a central cholinergic lesion. Since AChE is expressed on the surface of various blood cells too, the AChE activity of lymphocytes and erythrocytes was determined to test the possibility whether the cholinergic lesion is also reflected on these readily available cells. The AChE activity of lymphocytes in SDAT and in alcoholic dementia (AD) were significantly lower as compared to those of the age-matched healthy volunteers. In contrast, there was no significant difference in the activity of lymphocyte AChE between age-matched healthy controls and patients with multi-infarct dementia of vascular origin (MID). No changes could be demonstrated in the erythrocyte AChE activities of the patients studied, and the age-matched healthy individuals, when comparing them to the healthy blood donors. The AChE activity of lymphocytes may thus be a useful marker to follow the alterations in the metabolism of acetylcholine (ACh) in the central nervous system (CNS) of different types of dementia.

Acetylcholinesterase activity of lymphocytes: an enzyme characteristic of T-cells

Acetylcholinesterase (AchE) activity of normal human peripheral blood lymphocytes was determined by an adaptation of the colorimetric and radiometric techniques described for other cells. The enzyme activity seemed to be correlated to the number of T-lymphocytes in the blood. To decide whether only the T-cells possess AchE activity the lymphocytes were separated on Leucopac filter and on Percoll density gradient. B-lymphocytes had no detectable enzyme activity, while the T-lymphocyte fraction represented the total activity measured in the unseparated sample. The majority of AchE activity could be demonstrated in T-lymphocytes of lower density (TLD). The role of AchE in the plasma membrane of various blood cells is not known. Nevertheless, the enzyme is a good marker of the integrity and functional state of the membrane. The difference observed in AchE activity of the lymphocyte populations seems to be suitable for using it to characterize T-lymphocytes.

Acetylcholinesterase (AchE) activity of lymphocytes in chronic lymphoid leukemia (CLL)

The specific AchE (EC 3.1.1.7) activity of lymphocytes from the peripheral blood of normal donors was determined. On Leukopak filter the isolated T lymphocytes showed activity, whereas in stepwise Percoll gradient, population TLD displayed enzyme activity. The THD and B cells were inactive. [Szelényi J. G., Bartha E. & Hollán S. R. (1982) Br. J. Haemat. 50, 241]. A mixed cell population derived from CLL patients had significantly lower enzyme activity than normal. With the progress of B-cell proliferation AchE activity decreased in parallel with the number of T cells. The sp. act. of TLD population isolated from CLL patients was the same as that of normal donors whereas their B cells were inactive.