Evaluation of serum magnesium differences in hypertensive crises and control patients: A randomly matched case-control study

Although the role of magnesium in blood pressure has been well studied among hypertensive patients, no study has explored the role of magnesium in hypertensive crises. The primary objective of this study is to evaluate the differences in serum magnesium levels between hypertensive crises patients and matched controls (age‐, sex‐, race‐, and diabetes‐matched) in a 1:1 random match. This study is a single‐center, retrospective, chart review, case‐control study of patients with hypertensive crises (case group) and patients without hypertensive crises (control group). Patients were included in the case group if they were 18 years of age or older with hypertensive crises and have a documented magnesium level. The control group patients were required to be 18 years of age or older, have no diagnosis of hypertensive crises, and have a documented magnesium level. The primary outcome of the study was to compare the mean serum magnesium in patients with hypertensive crises versus patients without hypertensive crises. Three hundred and fifty‐eight patients were included in the study: 179 patients in both the case group and control group. The primary outcome results showed that serum magnesium concentration was not significantly different between the case group (1.89 ± 0.29 mg/dl) and control group (1.90 ± 0.31 mg/dl) (p = .787). This study found no significant difference in serum magnesium levels in patients with hypertensive crises compared to a random matched control group. Larger observational or experimental studies may be useful to evaluate the effect of magnesium on blood pressure in hypertensive crises.

Does steroid pretreatment increase endotoxin release during clinical cardiopulmonary bypass?

OBJECTIVE

The mechanism involved in the endotoxemia frequently recognized during cardiopulmonary bypass remains unclear. It has also been suggested that endotoxin levels were higher in steroid-pretreated patients undergoing cardiopulmonary bypass.

METHODS

Twenty patients undergoing cardiopulmonary bypass were randomly pretreated with steroids (methylprednisolone, 30 mg/kg) or placebo. Blood samples for endotoxin measurement were drawn simultaneously from the superior and inferior venae cavae before heparin administration, 5 and 50 minutes after the onset of bypass, 5 minutes after aortic declamping, at the end of bypass, and 1, 2, and 20 hours after the end of cardiopulmonary bypass.

RESULTS

The perioperative variables in the two groups were similar. Blood endotoxin levels were higher in the inferior vena cava than in the superior vena cava immediately after the onset of bypass. Endotoxin levels in inferior vena cava blood were significantly lower in steroid-pretreated patients than those in patients not receiving steroids.

CONCLUSIONS

Endotoxin is released during cardiopulmonary bypass from the region drained by the inferior vena cava. Steroid pretreatment may actually reduce endotoxin release during bypass.

Can cardioplegia management influence cytokine responses during clinical cardiopulmonary bypass?

BACKGROUND

Cytokines play an important role in the inflammatory response associated with cardiopulmonary bypass (CPB) and may contribute to postoperative complications. Although it has been shown that the production of tumor necrosis factor a (TNF-a) and interleukin (IL)-6 were higher following normothermic CPB than hypothermic CPB, whether different cardioplegic management could influence the release of cytokines remains unknown.

METHODS

We compared the blood concentrations of four cytokines (TNF-a, IL-6, IL-8, and IL-10) in two groups of patients undergoing complete revascularization with CPB in the same study period. Seventeen patients received cold crystalloid cardioplegia at a Belgian center (group-CC), while 21 patients received warm blood cardioplegia at a center in Hong Kong (group-WB). Blood samples were collected before and after surgery in each patient.

RESULTS

There were no differences between the 2 groups in terms of age, sex ratio, number of grafts, duration of CPB and aortic crossclamping. All patients survived their hospital stay. The levels of TNF-a, IL-6 and IL-8 after surgery were higher in group-CC than in group-WB. However, IL-10 levels were significantly lower at the end of surgery in group-CC than in group-WB.

CONCLUSIONS

Our data suggest that the use of warm blood cardioplegia, rather than cold crystalloid cardioplegia, may reduce the inflammatory response to CPB. This observation warrants future randomized investigation to determine its clinical relevance.

Hepatic release of interleukin-10 during cardiopulmonary bypass in steroid-pretreated patients

With its antiinflammatory properties, interleukin (IL)-10 may play an important role in limiting complications associated with cardiopulmonary bypass (CPB). We previously demonstrated that pretreatment with steroids can significantly increase IL-10 production during CPB, but neither the heart nor the lung was found to be its main source. To define whether the liver is the source of IL-10, hepatic venous cannulation was performed in 12 patients undergoing CPB. Each patient received 30 mg/kg of methylprednisolone before operation. Plasma levels of IL-10 were simultaneously measured in peripheral arterial blood and hepatic venous blood before heparin administration, before aortic cross-clamping, and 5, 30, 60, 90, and 120 minutes after aortic declamping. The duration of CPB and aortic cross-clamping was 113 +/- 7 minutes and 75 +/- 6 minutes (mean +/- SEM), respectively. IL-10 levels 30 minutes after declamping were significantly higher in hepatic venous blood than in arterial blood (1187 +/- 573 pg/ml vs 911 +/- 405 pg/ml, p < 0.01 by Wilcoxon's signed-rank test). To determine whether steroids can also induce the release of another antiinflammatory cytokine, IL-4, plasma IL-4 levels were measured simultaneously. IL-4 was detected in the arterial blood of only 4 of the 12 patients, transiently after aortic declamping. IL-4 was not detected in hepatic venous blood. In conclusion, the liver is a major source of IL-10 during CPB. However, steroid-treated patients do not show an increase in IL-4, and the liver is not the source of IL-4 during and after CPB.

Preoperative endoscopic retrograde cholangiopancreatography: therapeutic impact in a general population of patients needing a cholecystectomy

BACKGROUND/AIMS

The place of endoscopic retrograde cholangiopancreatography (ERCP) before open or laparoscopic cholecystectomy remains controversial. Most of the reports study highly selected series of patients and therefore do not give a survey of the actual situation in a general population. We describe here the therapeutic impact of preoperative ERCP in a continuous cohort of patients needing a cholecystectomy.

MATERIAL AND METHODS

Data concerning a 2-year continuous and unselected series of 452 patients undergoing cholecystectomy were evaluated.

RESULTS

Two hundred ninety-three patients (65%) presented with a chronic symptomatic biliary lithiasis and 159 patients (35%) with a complicated biliary lithiasis. A preoperative ERCP was performed in 206 patients, all presenting with a suspicion of associated lithiasis of the common bile duct (CBD). An endoscopic sphincterotomy was performed in 106 patients: 44 patients presented with CBD stones (9.7%), all successfully cleared by endoscopy. Laparoscopic cholecystectomy has been attempted in 367 patients (81%) and successfully performed in 333 patients (74%). Laparotomy as a first-choice procedure was performed in 85 patients (19%). Surgical choledochotomy was never performed. Postoperative ERCP was needed in 4 patients (0.88%) and in only 1 of them for a retained CBD stone (0.22%).

CONCLUSIONS

In a continuous series of patients needing a cholecystectomy, preoperative ERCP was performed on the basis of suspected CBD disorders. It allows CBD stone detection and extraction in almost 10% of the patients and avoids peroperative CBD exploration, with a very low rate of retained stones after surgery. The association of preoperative ERCP with subsequent laparoscopic cholecystectomy (when feasible) offers the patient a quick recovery and a short hospital stay.

Results of mitral valve reconstruction. Experience of Hôpital Erasme, ULB, Brussels

BACKGROUND

Reconstructive surgery of the mitral valve has been an alternative to mitral valve replacement in patients with mitral regurgitation. In order to evaluate the early results of mitral valve reconstruction, 38 consecutive cases were analyzed.

METHODS

Between January 1985 and May 1993, 38 patients with mitral valve incompetence were treated with a system of reconstructive techniques. Nineteen (52%) of the patients were in NYHA functional class II and seventeen (45%) in class III or IV preoperatively. The cause of the mitral disease was degenerative in 25 (66%), rheumatic in 6 (15%) and ischaemic in 5 (13%) patients. Isolated mitral valve repair was performed in 25 patients (66%); the remainder underwent associated procedures that included a myocardial revascularization in 9 patients (23.6%). Thirty-eight patients (100%) underwent a ring annuloplasty. Resection of the posterior leaflet was performed in 24 patients (63%).

RESULTS

There was one operative death (2.6%) and two late deaths (5.3%). Postoperatively, four patients sustained embolic events (incidence 10.5%). Six patients (15.8%) were precociously reoperated within the following month; two patients required valve replacement, one had mediastinitis and three other ones needed a pericardial drainage. Patients routinely received acenocoumarol anticoagulation for two months. Mean follow-up was 33 months (range 6 to 104) and one patient was lost to follow-up. Two years actuarial survival was 91.4%. There were no thromboembolic complications in the follow-up period. No patient was reoperated for valvular insufficiency beyond this time limit. One patient had late endocarditis and has been reoperated for mitral replacement (2.6%). After surgery, 34 survivors (89.5%) were in the NYHA functional class I or II.

CONCLUSIONS

These results demonstrate that mitral valvuloplasty is associated with lower operative mortality rates. Preservation of the mitral valve mechanism raised the performance of the left ventricle after reconstructive surgery. The incidence of reoperation and thromboembolism was low.

Benign thoracic schwannoma and postoperative chylothorax: case report and review of the literature

Among all the neurogenic tumours, the benign intrathoracic schwannoma is a rare tumour. Most often it is discovered by accident in the course of a routine X-ray examination of the thorax. Symptoms appear only when size becomes important. The surgical removal of an intrathoracic schwannoma may result in the development of a chylothorax. According to the literature, its treatment remains controversial. The originality of the case we report here is on the one hand the exceptional size of the tumour and the success over the long term of conservative treatment with complete parenteral alimentation, and on the other hand, the inefficacy of the subcutaneous administration of the analogue of somatostatin in reducing a chylothorax with high outflow.

[Bone metastasis of a prostate tumor and osteosynthesis material. A case report]

The detection of metastatic deposits at the site of previous osteosynthesis is difficult. Bone imaging and scanning with technectium 99m are unhelpful in differentiating between osteomyelitis, Paget's disease and a bone metastasis. The authors present details of a patient who had undergone osteosynthesis for a fracture of the left tibia in 1983. In October 1989 signs of inflammatory change appeared at the site of the previous fracture. It was initially treated as if it were osteomyelitis, with curettage and insertion of gentamycin beads, although no organisms were grown. Eventually the patient was transferred to the author's hospital and further investigation revealed a carcinoma of the prostate. Histological examination of biopsy specimens from the left tibia confirmed the presence of a metastasis from this growth.

Dose dependency of aminophylline effects on hemodynamic and ventricular function in patients with chronic obstructive pulmonary disease

The effects of aminophylline on pulmonary vascular tone, systemic hemodynamics, and ventricular ejection fractions reported in the literature show some discrepancies. We therefore studied in COPD patients the effects of aminophylline on hemodynamics, on ventricular ejection fractions, and on systolic and diastolic functions of each ventricle, and we measured simultaneously the blood level of the drug. The analysis of the data revealed a relationship between the blood level of aminophylline and the variations of right ventricular ejection fraction (RVEF) (r = 0.83, p = 0.005), left ventricular ejection fraction (LVEF) (r = 0.76, p = 0.017), pulmonary vascular resistance index (PVRI) (r = -0.58, p = 0.096), systemic vascular resistance index (SVRI) (r = -0.60, p = 0.08), and right ventricular peak systolic pressure/end-systolic volume index (RVPSP/ESVI) (r = -0.75, p = 0.02). Modifications of ejection fractions and vascular resistance indices were correlated for both ventricles (RVEF vs PVRI, r = -0.77, p = 0.01; LVEF vs SVRI, r = -0.76, p = 0.02). Finally, RVEF modifications was also correlated to RVPSP/ESVI variation (r = 0.78, p = 0.01). These results suggest that even within the therapeutic range (10 to 20 mg/L), the effects of aminophylline seemed to depend on its blood level. This dose dependency could explain the contradictory data reported in the literature concerning the effects of aminophylline on pulmonary and systemic hemodynamics and on ventricular function.

Acute effects of nifedipine on systolic and diastolic ventricular function in patients with chronic obstructive pulmonary disease

To evaluate how nifedipine influences systolic and diastolic ventricular function, the effects of 20 mg sublingual nifedipine were studied in 13 stable COPD patients. Nifedipine induced no change in mean pulmonary arterial pressure, decreased mean arterial pressure, pulmonary and systemic vascular resistance index, and increased heart rate and cardiac index. It also caused an increase in right and left ventricular ejection fractions. The end-diastolic volume index of both ventricles remained unchanged, whereas the end-systolic volume index tended to decrease without reaching a significant level, and the right ventricular contractility increased. After nifedipine administration, right and left ventricular compliance increased. This study suggests that short-term administration of nifedipine improves the systolic function by a decrease in ventricular afterload and an increase in ventricular contractility and increases the ventricular compliance by a reflex sympathetic stimulation and an afterload reduction.

Volumetric response of right ventricle during progressive supine exercise in men

Right ventricular (RV) adaptation to supine exercise has been studied in 10 young male volunteers by 81mKr electrocardiogram (ECG)-gated radionuclide ventriculography. During progressive supine exercise, the ejection fraction gradually increased from a mean value of 46% at rest up to 60% at a maximal exercise level. End-diastolic volume however remained unchanged at a low exercise level and even slightly decreased at a higher exercise level. Little or no change in end-diastolic volume and an increase in ejection fraction produced a significant decrease in end-systolic volume and a net increase in stroke volume. These results indicate that the Frank-Starling mechanism does not contribute to the increase in right ventricular stroke volume during progressive supine exercise, but the increase in right ventricular stroke volume rather seems related to an increased contractility, presumably mediated by an increased sympathetic activity.

Prediction of pulmonary arterial pressure in chronic obstructive pulmonary disease by radionuclide ventriculography

Pulmonary arterial hypertension represents an important parameter for the assessment of the severity of chronic bronchitis. The measurement of the pulmonary arterial pressure, however, requires invasive techniques of limited routine use because of costs and associated risks. The aim of this study is to evaluate whether the 81mKr right ventricular ejection fraction and parameters derived from equilibrium 99mTc red blood cells' right ventricular curve allow a better estimation of PAP than the 99mTc RVEF. In 41 patients with severe chronic bronchitis, the linear correlation between PAP and 99mTc RVEF was -0.61 (p less than 0.001). None of the parameters derived from the right ventricular curve was better correlated to PAP than the 99mTc RVEF. In 16 other chronic bronchitis patients, the 81mKr RVEF correlated moderately to PAP. In conclusion, the alternative isotopic methods proposed in this work do not provide a reliable estimation of pulmonary arterial pressure in patients with chronic bronchitis.

How does salbutamol improve the ventricular performance in patients with chronic obstructive pulmonary disease?

To evaluate the influence of beta 2 mimetics on ventricular contractility and pump function, radionuclide ventriculography and right heart catheterization were simultaneously performed in 10 patients with severe chronic obstructive pulmonary disease. After a 60 min constant infusion of 17 micrograms/min salbutamol, cardiac index increased by 60%, heart rate by 39%, and stroke volume index by 14%. Mean pulmonary artery pressure remained unchanged and mean arterial pressure decreased slightly but not significantly. Right ventricular (RV) function improved as attested to by an increase of RV ejection fraction (+8%), a decrease of RV end-diastolic pressure (-5 mm Hg), and RV end-systolic volume index (-18%). Simultaneously, the pulmonary vascular resistance index decreased by 33% and RV contractility, appreciated by RV dP/dtmax, RV (dP/dtmax)/P, and RV end-systolic pressure/volume ratio, increased by 44, 77, and 27%, respectively. Left ventricular (LV) function also improved. The LV ejection fraction increased by 18% and LV end-systolic volume decreased by 34%. Concomitantly, the systemic vascular resistance index decreased by 40% and the LV end-systolic pressure/volume ratio increased by 50%. Our results suggest that the infusion of salbutamol improves ventricular performance by a decrease of ventricular afterload and by a positive inotropic effect.

Calcium chloride in experimental electromechanical dissociation: a placebo-controlled trial in dogs

While calcium administration has been recommended in CPR, its beneficial effects have been challenged. The effectiveness of calcium chloride was evaluated and compared with epinephrine during successive episodes of electromechanical dissociation (EMD) after ventricular fibrillation in closed-chest dogs. Each of three successive episodes of CPR was randomly and blindly treated by repeated (every 2 min) injections of 5 ml H2O plus either 500 mg of calcium chloride (CaCl2), 1 mg of epinephrine (Epi), or 5% dextrose (D5W). Of 42 CPR attempts performed on 16 dogs, 16 were reversed by only chest compression and artificial ventilation. For the 26 CPR with pharmacologic intervention, recovery was obtained after one injection in 5 of 6 Epi but only in 4 of 11 CaCl2 and 4 of 9 D5W. Only four CPR attempts were ultimately unsuccessful, all in CaCl2 group. During recovery, the Epi group showed significantly higher arterial pressures and heart rates but less severe acidemia. In this model, calcium chloride alone is ineffective during EMD.

[Interaction of two isomers, N-nitrosomethylphenylamine, N-nitroso derivative, and p-nitrosomethylaniline with microorganisms]

There exists a relationship between the chemical structure C--NO or N--NO and biological effects. p-nitrosomethylaniline, a C-nitroso compound, in contrast to its isomer, N-nitrosomethylphenylamine, a N-nitroso derivate, shows a marked action against microoganisms and is, alone, reduced enzymatically.

[Study of the degradation reaction of paranitrosodimethylaniline by a C-nitrosoreductase of yeast]

We have purified, by a three step procedure, a yeast C-nitrosoreductase and studied its action on p-nitroso-N,N-dimethylaniline. Microcalorimetric measurements performed on the microcalorimeter LKB "batch", have been given the number of protons exchanged during the reaction : four protons are involved. Two are given by NADH and the others are supplied by the buffer. We could observe two steps in the catalytic mechanism. The enthalpy change of the first one is greater than that of the second. Spectrophotometric and polarographic experiments corroborate this results : two enzymatic steps could be demonstrated. The reduction of p-nitroso-N,N-dimethylaniline is characterized by a peak with a half wave potential at -0,31 V (in M Tris-HCl, pH 8,30). While the amplitude of this one decreases, a second wave appears at -1,03 V.