Intrathecal morphine and clonidine for coronary artery bypass grafting

BACKGROUND

After cardiac surgery adequate postoperative analgesia is necessary. We assessed analgesia using intrathecal morphine and clonidine.

METHODS

In a double-blind randomized study, 45 patients having coronary artery bypass graft surgery were allocated randomly to receive i.v. patient-controlled analgesia (PCA) morphine (bolus, 1 mg; lock-out interval, 7 min) (control group), either alone or combined with intrathecal morphine 4 microg kg(-1) or with both intrathecal morphine 4 microg kg(-1) and clonidine 1 microg kg(-1). Intrathecal injections were performed before the induction of general anaesthesia. Pain was measured after surgery using a visual analogue scale (VAS). We recorded i.v. PCA morphine consumption during the 24 h after operation.

RESULTS

Morphine dosage [median (25th-75th percentiles)] was less in the first 24 h in the patients who were given intrathecal morphine + clonidine [7 (0-37) mg] than in other patients [40.5 (15-61.5) mg in the intrathecal morphine group and 37 (30.5-51) mg in the i.v. morphine group]. VAS scores were lower after intrathecal morphine + clonidine compared with the control group. Time to extubation was less after intrathecal morphine + clonidine compared with the i.v. morphine group [225 (195-330) vs 330 (300-360) min, P<0.05].

CONCLUSION

Intrathecal morphine and clonidine provide effective analgesia after coronary artery bypass graft surgery and allow earlier extubation.

Co-immunization of rhesus macaques with plasmid vectors expressing IFN-gamma, GM-CSF, and SIV antigens enhances anti-viral humoral immunity but does not affect viremia after challenge with highly pathogenic virus

To investigate the adjuvant capacity of granulocyte-macrophage colony-stimulating factor (GM-CSF) and interferon (IFN-gamma), we cloned these rhesus cytokines into a mammalian expression vector. Two groups of six rhesus macaques (Macaca mulatta) received intradermal immunizations of plasmid DNA coding for SIV Eng and Gag, and influenza virus nucleoprotein (Flu-NP), with or without the co-administration of plasmid DNA coding for these cytokines. Humoral immune responses to antigens of both of these viruses and SIV specific T cell proliferative responses were significantly enhanced by co-immunization with the cytokines. These twelve monkeys, and a group of six naive controls, were challenged by the oral mucosal route with the uncloned and highly pathogenic SIVmac251. All monkeys became infected. The early CD4 decline was reduced in the group co-immunized with cytokine and viral plasmids. Unexpectedly, plasma viremia set points were not different in this co-immunized group and the non-immunized control group. On the other hand, monkeys vaccinated with equivalent amounts of empty vector plasmid (i.e. no cytokine inserts) along with plasmids expressing viral antigens demonstrated a slight but significant decrease in acute viremia compared to non-immunized controls (P<0.02). However, viral loads at set points were not significantly different between both the immunized and the non-immunized control group. Thus, although the cytokine vectors demonstrated detectable enhancement of the immune response to different viral antigens, such enhanced response did not translate into better anti-viral control in our experiment. These results underscore the need for further testing of cytokines as vaccine adjuvants in relevant animal models.

Comparison of emedastine 0.05% or nedocromil sodium 2% eye drops and placebo in controlling local reactions in subjects with allergic conjunctivitis

PURPOSE

To assess the efficacy of nedocromil sodium 2% eye drops and emedastine difumarate 0.05% eye drops in controlling the ocular allergic reaction induced by conjunctival allergen challenge (CAC).

METHODS

Thirty subjects with a personal history of allergic conjunctivitis were enrolled (first visit). At the second visit each subject randomly received emedastine 0.05% or nedocromil 2% in one eye and placebo in the other eye. Five minutes after the medication the offending allergen was instilled in both eyes. Ocular redness and itching were evaluated according to a standardized scoring system at 3, 10 and 20-minute intervals after instillation of the allergen. After one week (third visit) the whole procedure was repeated using the placebo in the eye used as control during second visit and one of the trial drug that was not used at second visit in the other eye (either emedastine or nedocromil).

RESULTS

Emedastine 0.05% and nedocromil 2% eye drops were more effective than placebo in controlling ocular redness and itching (p<0.01). Emedastine was more effective (p<0.01) than nedocromil in alleviating redness and itching 3 and 10 minutes after application of the allergen.

CONCLUSIONS

Emedastine 0.05% appeared superior to nedocromil 2% in producing immediate relief when subjects with allergic conjunctivitis were exposed to the offending allergen.

Retroesophageal subclavian artery aneurysm arising from Kommerell's diverticulum

This report describes a novel technique used for management of retroesophageal subclavian artery aneurysm arising from Kommerell's diverticulum. The procedure consists of endoaortic exclusion of the aneurysmal neck, using a prosthetic patch after sternotomy during circulatory arrest, and antegrade cold blood cerebroplegia. The advantages of this technique are avoidance of hemorrhagic complications during clamping of the aneurysmal neck, limiting of the extent of dissection of the aortic arch, and elimination of the risk of inadvertent left recurrent nerve paralysis. Antegrade cold blood cerebroplegia provides good cerebral protection and decreases the duration and consequences of extracorporeal circulation.

Simian immunodeficiency virus in kidney cell cultures from highly infected rhesus macaques (Macaca mulatta)

Trace amounts of simian immunodeficiency virus (SIV) proviral DNA were detected in monolayers of primary kidney cells from two rhesus macaques (Macaca mulatta) heavily infected with the highly pathogenic strain SIVmac251. There was no detectable infectious SIV in the supernatant from the kidney cell cultures obtained from either monkey. However, infectious SIV was rescued by co-culture of kidney cells with a permissive lymphoid cell line. Macrophages, present in these cultures, may be the reservoir for the proviral genomes.

[Motor deficit of the lower limbs and urinary incontinence following peridural anesthesia]

Neurological complications of epidural anaesthesia are rare, but can be severe. We report the case of a 49-year-old man, with a history of non equilibrated diabetes, who experienced after an epidural anaesthesia for peripheral vascular surgery a polyneuropathy with muscle weakness of the lower extremities associated with a transient urinary incontinence. A spinal compression was excluded by computed tomography and magnetic resonance imaging. Electromyography showed an impaired nervous motor conduction. An aggravation of a pre-existing diabetic and alcoholic polyneuropathy, associated with possible spinal ischaemia of multifactorial origin could be the cause of these complications. This case emphasizes the importance, during preanesthetic assessment of candidates for epidural or spinal anaesthesia, to search for a possible unrecognized neuropathy at risk of aggravation by regional anaesthesia.

Increased expression of tissue factor mRNA and procoagulant activity in ovine lentivirus-infected alveolar macrophages

To link ovine lentivirus infection to lung tissue damage, we studied the procoagulant response in alveolar macrophages from experimentally infected lambs and in in vitro infected alveolar macrophages. We cloned ovine tissue factor cDNA and analysed its in vitro expression by Northern blotting. Visna-maedi virus induced tissue factor mRNA. In order to correlate this mRNA induction with its cellular function, we analysed macrophage procoagulant activity after in vitro and in vivo infection. The procoagulant activity was increased by interaction with the virus in both cases. Thus, visna-maedi virus-induced expression of tissue factor mRNA was associated with enhanced macrophage procoagulant activity. These findings indicate an active role of alveolar macrophages in the pathogenesis of these inflammatory lung lesions.

[Coronary transluminal angioplasty using 6-french diagnostic catheters. A preliminary study]

This preliminary study was undertaken to assess the potential indication and limitations of the use of 6 French guiding catheters for percutaneous transluminal coronary angioplasty (PTCA). Between September 1992 and October 1993, 100 consecutive patients with an average age of 64 +/- 11 years underwent 6 F angioplasty for: stable angina (38.7%), unstable angina (32.4%), non Q-wave or infarction recanalized by thrombolytic therapy (18%), and acute myocardial infarction (10.8%). Eighty per cent of the pTCAs were performed immediately after diagnostic coronary angiography. Single vessel disease accounted for 93.7% of cases. Of the 118 lesions treated, 46.6% were types A or B1, 44.9% were type B2 and 8.4% were type C. The success rate of 6 F PTCA was 96.4% using an average of 1.08 guides and 1.25 balloon catheters per patient. Stenosis decreased from 83 +/- 10% to 26 +/- 16%. There were 4 technical failures: in 1 case it was not possible to pass a chronic occlusion, in 1 case coronary dissection was complicated by infarction, and in 2 cases a 7 F guiding catheter was required for successful PTCA. No patients required emergency coronary bypass surgery and there were no fatalities during the procedure. Four patients required perfusing balloon catheters and 8 were stented with a Palmaz-Schatz endoprosthesis with the 6 F catheter. These results are comparable to those obtained with larger diameter guiding catheters. In view of the good coronary ostial tolerance, the lower rate of local complications at the site of arterial puncture and the possibility of earlier mobilisation of patients after the procedure, the indications for 6 F PTCA should increase.

[Technical problems during coronary revascularization in case of massive calcified aorta]

A massively calcified ascending aorta which may make aortic clamping impossible, is a major obstacle to coronary revascularisation surgery. The aim of this study was to demonstrate that by the use of certain technical modifications, these patients can be treated even in multivessel disease. In the author's experience, two patients with this condition underwent complete revascularisation with a good surgical result controlled by angiography. The sites of arterial cannulation were the aortic arch in one case, the brachiocephalic artery and the common femoral artery in the other case. The ascending aorta was not clamped in either patient or used as the origin of the coronary bypass grafts. Myocardial protection was performed by systemic cooling with ventricular fibrillation without cardioplegia. The feasibility of these methods has led to the suggestion of a classification of the aortic wall according to peroperative palpation. This classification would provide indications for the use of technical modifications not only in extreme cases of aortic calcification but also in patients with severe atherosclerotic changes at high neurological risk; it would not, however, interfere with the classical technique of revascularisation.

Isolation of Rift Valley fever virus from human peripheral blood mononuclear cells: Mauritanian epidemic

During the Mauritanian Rift Valley fever (RVF) epidemic of 1987, peripheral blood mononuclear cells (PBMC) were studied from 78 sick patients. RVF virus (RVFV) was isolated in 5 cases, on Aedes pseudoscutellaris AP61, from both PBMC and serum. Among the 78 cases studied, RVF was proven in 19 cases (24.3%) by specific IgM detection, and in 12 cases (15.3%) by virus isolation from serum, of which 3 also exhibited anti-RVF IgM. Among the 5 PBMC-positive RVFV cases, 2 strains were isolated in the presence of specific IgM from patients presenting with neurologic signs. These observations raised the question as to the role of specific IgM in cellular infection, and suggest that, in certain cases, mononuclear cells may promote RVFV dissemination into brain cells. Further investigations need to be undertaken to determine the RVFV receptor expressed on PBMC membranes.

Filter paper confetti in a serological Rift Valley fever survey

In order to collect epidemiological data about the Rift Valley fever epidemic in Mauritania, we decided to use the filter paper method. The mean recovery level of specific antibodies from filter paper, tested using an immunoenzymatic method, is around one fourth. Taking the mean haematocrit into account, we estimated the extract square with a 1/300 dilution. This method was very useful for epidemiological studies, we observed few patient refusals, but it is necessary to know the exact specificity of the antibodies.

[Inhibition of postoperative muscular proteolysis by sodium alpha-ketoisocaproate: does a dose-effect relation exist?]

The inhibitory effect of branched chain amino acids on muscle protein breakdown has been attributed to the ketoanalogue of leucine, alpha-ketoisocaproic acid. In an attempt to demonstrate a possible dose-response relationship for ketoleucine, the postoperative protein breakdown (using urinary excretion of 3-methylhistidine, creatinine and nitrogen) was evaluated in 29 patients undergoing gynaecological surgery. They were randomly assigned to one of the following groups: group A (ten patients) received 3 g of glucose per kilo and per day, group B (ten patients) received glucose + 100 mg X kg-1 X d-1 of ketoleucine and group C (nine patients) glucose + 200 mg X kg-1 X d-1 of ketoleucine. The study was performed over a period of 72 h. The 3-methylhistidine/creatinine ratio was significantly lower in groups B and C than in group A (respectively 28.47, 28.07 and 32.08). These results confirmed the inhibitory effect of ketoleucine on muscle protein breakdown. However there was no difference between group B and group C. In conclusion, this study did not demonstrate a dose-response relationship for ketoleucine in moderate postoperative catabolism.

[Postoperative weaning from mechanical ventilation in adults]

Pulmonary complications remain the most frequent of postoperative complications (32-60), especially after upper abdominal surgery (14-41). Chronic respiratory insufficiency (80) also continues to be a major risk factor, in spite of the progress made in both anesthesiology and postoperative care. In the immediate postoperative period, weaning from mechanical ventilation is one of the most dangerous phases of anesthesia (84). We discuss the importance of weaning procedures, in particular, in patients with a high risk of pulmonary complications.