A clinical study to evaluate the cardiopulmonary characteristics of two different anaesthetic protocols for immobilization of healthy chimpanzees (Pan troglodytes).

OBJECTIVE: To characterize the cardiopulmonary characteristics of two different anaesthetic protocols (tiletamine/zolazepam ± medetomidine) and their suitability for the immobilization of healthy chimpanzees undergoing cardiac assessment. STUDY DESIGN: Prospective, clinical, longitudinal study. ANIMALS: Six chimpanzees (Pan troglodytes) aged 4-16 years weighing 19.5-78.5 kg were anaesthetized on two occasions. METHODS: Anaesthesia was induced with tiletamine/zolazepam (TZ) (3-4 mg kg-1) or tiletamine/zolazepam (2 mg kg-1) and medetomidine (0.02 mg kg-1) (TZM) via blow dart [intramuscular (IM)] and maintained with intermittent boluses of ketamine (IV) or zolazepam/tiletamine (IM) as required. The overall quality of the anaesthesia was quantified based on scores given for: quality of induction, degree of muscle relaxation and ease of intubation. The time to achieve a light plane of anaesthesia, number of supplemental boluses needed and recovery characteristics were also recorded. Chimpanzees were continuously monitored and heart rate (HR), pulse rate (PR), respiratory rate (fR) oxygen saturation of haemoglobin (SpO2), systolic arterial pressure (SAP), diastolic arterial pressure (DAP), mean arterial pressure (MAP), rectal temperature, mucous membrane colour and capillary refill time recorded. During the first procedure (TZ) animals underwent a 12-channel electrocardiogram (ECG), haematology, biochemistry and cardiac biomarker assessment to rule out the presence of pre-existing cardiovascular disease. A detailed echocardiographic examination was carried out by the same blinded observer during both procedures. Data were compared using Student's paired t-test or Wilcoxon rank tests as appropriate. RESULTS: There was a significant difference for the area under the curves between anaesthetic protocols for HR, SAP, MAP and fR. No significant differences in the echocardiographic measurements were evident. Quality of anaesthesia was significantly better with TZM and no additional boluses were required. The TZ protocol required multiple supplemental boluses. CONCLUSIONS AND CLINICAL RELEVANCE: Both combinations are suitable for immobilization and cardiovascular evaluation of healthy chimpanzees. Further work is required to evaluate the effect of medetomidine in cardiovascular disease.

Effect of long-term thoracic epidural analgesia on refractory angina pectoris: a 10-year experience.

OBJECTIVES: In patients with refractory angina, the adjuvant effects of long-term home self-treatment with thoracic epidural analgesia on angina, quality of life, and safety were evaluated. DESIGN: A prospective, consecutive study. SETTING: A university hospital. PARTICIPANTS AND INTERVENTION: Between January 1998 and August 2007, 152 consecutive patients with refractory angina began treatment with thoracic epidural analgesia by intermittent injections of bupivacaine (139 home treatment and 13 palliative). Data were collected until August 2008; therefore, the follow-up for each patient was between 1 and 9 years. MEASUREMENTS AND MAIN RESULTS: All but 7 of the patients improved symptomatically, and the improvement was maintained throughout the period of treatment (median = 19 months; range, 1 month-8.9 years). After 1 to 2 weeks, the median (interquartile range [IQR]) Canadian Cardiovascular Society angina class decreased from 4.0 (3.0-4.0) to 2.0 (1.0-2.0), the mean ± standard deviation frequency of anginal attacks decreased from 36 ± 19 to 4.4 ± 6.8 a week, the nitroglycerin intake decreased from 27.7 ± 15.7 to 2.7 ± 4.9 a week, and the median (IQR) overall self-rated quality of life assessed by the visual analog scale increased from 25 (20-30) to 70 (50-75) (all p < 0.001). About one-third of the patients had a dislodgement of the epidural catheter. Apart from 1 epidural hematoma that appeared in 1 patient with a previously undiagnosed bleeding defect, no other serious catheter-related complications occurred. CONCLUSIONS: Long-term self-administered home treatment with thoracic epidural analgesia is a safe, widely available adjuvant treatment for patients with severe refractory angina. It produces symptomatic relief of angina and improves quality of life. The technical development of the method to protect the catheter against dislodgement is needed.

Mortality within 2 years after surgery in relation to low intraoperative bispectral index values and preexisting malignant disease.

BACKGROUND: A correlation between deep anesthesia (defined as time with Bispectral Index (BIS) <45; T(BIS <45)) and death within 1 yr after surgery has previously been reported. In order to confirm or refute these findings, we evaluated T(BIS <45) as an independent risk factor for death within 1 and 2 yr after surgery and also the impact of malignancy, the predominant cause of death in the previous report. METHODS: Mortality within 2 yr after surgery, causes of death and the occurrence of malignant disease at the time of surgery were identified in a cohort of 4087 BIS-monitored patients. Statistically significant univariate predictors of mortality were identified. In order to allow for comparison with previous data, the following multivariate analysis was first done without, and thereafter with, preexisting malignancy status, the predominant cause of death. RESULTS: One-hundred-seventy-four (4.3%) patients died within 1 yr and another 92 during the second year (totaling 6.5% in 2 yr). T(BIS <45) was a significant predictor of 1- and 2-yr mortality when preexisting malignant disease was not among the co-variates (hazard ratio [HR] 1.13 [1.01-1.27] and 1.18 [1.08-1.29], respectively). Further exploration confined the significant relation between postoperative mortality and T(BIS <45) to patients with preexisting malignant diagnoses associated with extensive surgery and less favorable prognosis. The most powerful predictors of 2-yr mortality in the model, including preexisting malignancy, were ASA physical score class IV (HR 19.3 [7.31-51.1]), age >80 yr (HR 2.93 [1.79-4.79]), and preexisting malignancy associated with less favorable prognosis (HR 9.30 [6.60-13.1]).When the initial multivariate regression was repeated using preexisting malignancy status among the co-variates in the model, the previously significant relation between 1, and 2-yr mortality and T(BIS <45) did not reach statistical significance. CONCLUSION: Using a similar set of co-variates as in previous work, we confirmed the statistical relation between 1-yr mortality and T(BIS <45), and we extended this observation to 2-yr mortality. However, this relation is sensitive to the selection of co-variates in the statistical model, and a randomized study is required to demonstrate that there really is a causal impact from and T(BIS <45) on postoperative mortality and, if it does, the effect is probably very weak in comparison with co-morbidity as assessed by ASA physical score, the preexisting malignancy status at surgery and age.

Axial flow pump treatment during myocardial depression in calves: an invasive hemodynamic and echocardiographic tissue Doppler study.

The aim of this study was to investigate flow characteristics and myocardial function after implantation of an axial pump left ventricular assist device while varying afterload and during progressive myocardial depression. Ten calves were included, seven of which fulfilled the protocol. Invasive hemodynamic monitoring and echocardiography with color-coded systolic tissue Doppler velocity (TD velocity) were used during prepump conditions, at three different pump speeds, during modification of the systemic vascular resistance (SVR), and during increasing degrees of beta-blockade. The TD velocity decreased with the myocardial function whereas left ventricular size, fractional shortening, and pump speed did not correlate significantly with the TD velocity. The TD velocity correlated significantly with native stroke volume, heart rate, SVR and cardiac output but none of these alone could explain more than 20% of the changes in TD velocity. The axial flow pump studied is effective in unloading the severely depressed heart and has a high capacity for maintaining an adequate cardiac output, regardless of differing hemodynamic conditions, pump speed or decreasing LV function. Echocardiography with volumetric rendering and TD velocity imaging are valuable tools for monitoring and quantifying residual myocardial function during pump treatment.

[A complementary clinical method to minimize air embolism during open-heart surgery]. / Kiegészíto klinikai módszer a nyitott szívmutéteknél fellépo légembolisatio csökkentésére.

Air from the left heart is ejected even up to several hours after cardiopulmonary bypass (CPB) despite the use of CO2. The following method is complementary in addition to surgical de-airing in order to further reduce the chance of air embolism, especially from the pulmonary veins. After re-expanding the lungs with standard bag inflation, the ventilation is restarted in consultation with the surgeon. The ventilator is set to the respiratory minute volume used before the CPB but at a respiratory frequency of 10/minutes whereas the regularly beating heart is filled from the heart lung machine. Transoesophageal echocardiography (TEE) reliably controls the effect.