[Hypophosphatemia in critically ill patients]. / Hypophosphorémie chez le malade grave.

Phosphorus is a mineral element essential to cellular function. The prevalence of hypophosphatemia is particularly high in critically ill patients. Hypophosphatemia may be the result of increased renal excretion, reduced digestive absorption, intracellular shift accompanied or not by depletion of the total phosphorus pool, and extreme catabolic states. Clinical manifestations are especially apparent in severe hypophosphatemia and include impairments of the respiratory, musculo-skeletal, pulmonary, and neurological systems. Hypophosphatemia must be corrected, especially if it is severe and symptomatic.

[Laparoscopy under local anaesthesia and hypnoanaesthesia about 35 cholecystectomies and 15 inguinal hernia repair]. / Coeliochirurgie sous anesthésie locale et hypnosédation, à propos de 35 cholécystectomies et 15 cures de hernies.

OBJECTIVE: To present hypnosedation and the feasibility of this technique performed for laparoscopic procedure. STUDY DESIGN: Retrospective and descriptive study of feasibility. PATIENTS AND METHODS: Hypnosis can significantly reduce intraoperative requirements of intravenous sedation for surgery under local anaesthesia. Modifications of surgical procedure: laparoscopic surgery under local anaesthesia and hypnosis is performed using a subcutaneous lifting of anterior abdominal wall. Insufflation is only use to push out smoke. If patient or surgical uncomfort happens, moral contract with patient includes convert to general anaesthesia. RESULTS: We performed 35 cholecystectomies; 13 needed convert to general anaesthesia, mainly for peritoneal pain induced by CO(2) insufflation; 22 procedures were completed with patients' satisfaction. Upon 15-hernia repairs, only one patient needed convert to general anaesthesia, for dissection difficulty. CONCLUSION: Probably hypnosis can't be extent to intraperitoneal laparoscopic procedures. On the other hand interest of hypnosis performed for extraperitoneal laparoscopic hernia repair must be explore.

Metabolic effects of arginine addition to the enteral feeding of critically ill patients.

BACKGROUND: Some studies have suggested that the addition of arginine to enteral feeding solutions may improve outcome in critically ill patients, but the mechanism is incompletely explained. In particular, the availability and utilization of arginine administered enterally is not well defined. METHODS: This prospective, randomized, double-blind, placebo-controlled study performed in a Department of Medicosurgical Intensive Care included 51 patients likely requiring long-term enteral feeding. Thirty-seven patients (57 +/- 7 years, SAPS II 33 +/- 6) completed the 7-day study, of whom 20 received the formula enriched with free arginine (6.3 g/L) and 17 received an isocaloric and isonitrogenous control solution. Arginine absorption was assessed from plasma arginine concentrations in serial samples. Three pathways of arginine utilization were explored: (1) the production of nitric oxide, assessed by the plasma concentration of nitrite/nitrate (NOx) and citrulline, and 24-hour urinary excretion of NOx; (2) the protein turnover, estimated by the phenylalanine concentrations; and (3) the activity of arginase, reflected by the ornithine concentration. RESULTS: The plasma concentrations of arginine and ornithine increased in the group fed with the enriched formula (from 55 +/- 9 micromol/L to 102 +/- 9 micromol/L and from 57 +/- 7 to 135 +/- 11 micromol/L, respectively, p < .05), but not with the control formula. There was no difference between groups in either NO production or phenylalanine concentration. CONCLUSIONS: Supplemental arginine in enteral feeding is readily absorbed, and mainly metabolized into ornithine, presumably by the arginase enzyme.

Effects of alpha - and beta -adrenergic stimulation on hepatosplanchnic perfusion and oxygen extraction in endotoxic shock.

OBJECTIVE: To examine the effects of adrenergic stimulation on hepatosplanchnic perfusion, oxygen extraction, and tumor necrosis factor-alpha production during endotoxic shock. DESIGN: In vivo, prospective, randomized, controlled, repeated-measures, experimental study. SETTING: Experimental physiology laboratory in a university teaching hospital. SUBJECTS: Twenty-one anesthetized and mechanically ventilated dogs. INTERVENTIONS: An intrapericardial catheter was positioned. Catheters for blood sampling were inserted into the right femoral artery, hepatic vein, portal vein, and pulmonary artery. Ultrasonic flow probes were placed around the portal vein, the hepatic artery, the mesenteric artery, the left renal artery, and the left femoral artery. Animals received 2 mg/kg of Escherichia coli endotoxin, followed by fluid resuscitation. Seven dogs received intravenous isoproterenol (0.1 microg/kg x min(-1)), seven received phenylephrine (1 microg/kg x min(-1)), and seven served as controls. Thirty minutes later, cardiac tamponade was introduced to study organ perfusion and tissue oxygen extraction capabilities. MAIN RESULTS: The isoproterenol group had a higher cardiac index and stroke index and lower systemic vascular resistance than the other groups. The phenylephrine group had a higher arterial pressure but a lower cardiac index than the isoproterenol group. The isoproterenol group had a higher hepatic artery blood flow than the other groups and a higher portal and mesenteric flow than the control group. Liver and gut mucosal blood flow was greater in the isoproterenol than in the phenylephrine group. The isoproterenol group had a lower global critical oxygen delivery than the other groups (8.8 +/- 1.3 vs. 13.1 +/- 2.0 (control) and 11.8 +/- 3.3 mL/kg x min(-1) (phenylephrine); both p < .05) and a higher liver critical oxygen extraction ratio than the control group. Isoproterenol tended to attenuate, but phenylephrine significantly increased, blood tumor necrosis factor levels. CONCLUSIONS: During endotoxic shock, beta-stimulation can improve hepatosplanchnic perfusion and enhance tissue oxygen extraction capabilities, whereas alpha-stimulation does not. In addition, alpha-adrenergic stimulation can increase tumor necrosis factor levels.

Enteral feeding with a solution enriched with antioxidant vitamins A, C, and E enhances the resistance to oxidative stress.

OBJECTIVE: To assess whether dietary supplementation with the antioxidant vitamins A, C, and E enhances parameters of oxidative stress and influences the course of critically ill patients. DESIGN: Prospective, randomized, double-blinded, placebo-controlled study. SETTING: Department of medicosurgical intensive care of an academic hospital. PATIENTS: Fifty-one patients expected to require at least 7 days of enteral feeding. Thirty-seven of these patients (age, 57 +/- 7 yrs; Simplified Acute Physiology Score II, 33 +/- 6 points) completed the study. INTERVENTIONS: Twenty patients were randomized to receive the formula supplemented with vitamins A (67 microg/dL), C (13.3 mg/ dL), and E (4.94 mg/dL), and 17 patients received an isocaloric and isonitrogenous control solution. MEASUREMENTS AND MAIN RESULTS: Plasma levels of antioxidant vitamins, lipid peroxidation (estimated by the malonyldialdehyde assay), and low-density lipoprotein (LDL), and erythrocyte resistance to experimental oxidative stress were determined on samples drawn two consecutive days before the initiation of feeding and at the end of the 7-day period. Clinical outcome measures included documented infection and intensive care unit and 28-day survival. Administration of the supplemented solution increased significantly the concentration of plasma beta-carotene (from 0.2 +/- 0.0 microg/mL to 0.6 +/- 0.1 microg/mL; p < 0.01) and plasma and LDL-bound alpha-tocopherol (from 6.0 +/- 0.4 microg/mL and 2.9 +/- 0.9 microg/mL to 9.7 +/- 0.5 microg/mL and 4.3 +/- 1.2 microg/mL, respectively; p < 0.05), and improved LDL resistance to oxidative stress by 21 +/- 4% (p < 0.05). No such change was observed in the control group. There was no significant difference in clinical outcome between the two groups. CONCLUSIONS: Supplemental antioxidant vitamins added to enteral feeding solutions are well absorbed. Dietary supplementation with vitamins A, C, and E is associated with an improvement in antioxidant defenses, as assessed by ex vivo tests.

Comparison of hypertonic with isotonic saline hydroxyethyl starch solution on oxygen extraction capabilities during endotoxic shock.

Hypertonic colloid solutions reportedly exert protective effects on the microcirculation. The present study investigated the effects of a hypertonic saline hydroxyethyl starch (HES) solution on the oxygen extraction capabilities in an endotoxic shock model in the dog. Fourteen anesthetized and mechanically ventilated dogs received 2 mg/kg of Escherichia coli endotoxin before being randomly divided into two groups to receive a 4 mLkg infusion in 10 min of either hypertonic (7.5%, n = 7), or isotonic (.9%, n = 7) HES solution. Thereafter, each animal received isotonic HES titrated to restore cardiac index to baseline levels, followed by a constant infusion of normal saline at 20 mLkg throughout the study. The amount of fluid required to restore cardiac index to baseline levels was approximately one-half in the hypertonic saline HES group as compared with the isotonic group (123+/-12 vs. 291+/-62 mLkg, p < .05). The two groups of dogs had similar mean arterial pressure and cardiac index values. Hypertonic saline HES-treated animals had a higher sodium concentration than the control group (144.4+/-4.0 vs. 138.7+/-3.1 mM/L, p < .05). There were no significant differences in blood gases or lactate concentrations between the groups. When cardiac tamponade was induced to study the tissue oxygen extraction capabilities, hypertonic saline HES-treated dogs had a slightly lower critical oxygen delivery (11.1+/-1.6 vs. 14.2+/-3.3 mL/kg x min, p = NS), and a significantly higher critical oxygen extraction ratio (61.9+/-17.1 vs. 44.0+/-11.5%, p < .05) than the isotonic group. We conclude that during endotoxic shock in dogs, hypertonic saline HES solution can increase whole body oxygen extraction capabilities, probably by an improvement in microvascular perfusion in septic conditions.

Calcium administration for cardiovascular support in critically ill patients: when is it indicated?

Calcium has a fundamental role in the maintenance of myocardial function and vascular tone. The ionized form of calcium is the most important physiologically, and this form needs to be measured to assess physiologically active calcium levels. Ionized hypocalcemia can occur as a result of various pathophysiological disturbances, and it is seen frequently in critically ill patients. Several investigators have observed a poorer prognosis in those patients with ionized hypocalcemia. It is unclear whether calcium supplementation is beneficial in these patients. It may improve cardiovascular performance, but, in contrast, it may contribute to cellular damage (especially during hypoxia following cardiopulmonary resuscitation). In sepsis, there may be an increased cellular influx of calcium, which may be deleterious to cellular function; indeed, calcium entry blockers in this situation may be protective. We review the role of calcium as an inotropic agent, its interaction with other inotropic agents, and its use during blood transfusion and during cardiopulmonary resuscitation.

Addition of alinidine, a specific bradycardic agent, to dobutamine in a canine model of endotoxic shock.

BACKGROUND AND METHODS: Alinidine is a recently developed antiarrhythmic medication that acts directly on the cardiac pacemaker cells to reduce heart rate (HR). At effective doses, alinidine might have cardiodepressant actions that could be hazardous in the presence of hemodynamic instability. On the other hand, one limitation of the use of catecholamines is tachycardia, and alinidine could be beneficial in situations such as septic shock, where adrenergic agents are commonly required. The present study explored the hemodynamic and gasometric effects of alinidine during dobutamine administration in a canine model of septic shock induced by endotoxin administration. In ten pentobarbital-anesthetized, mechanically ventilated dogs (weight 28 +/- 4 kg), Escherichia coli endotoxin (3 mg/kg) injection was followed 30 mins later by saline infusion to restore and maintain pulmonary artery occlusion pressure at the baseline value. Sixty minutes after the endotoxin administration, a dobutamine infusion was started at a rate of 10 micrograms/kg/min. Thirty minutes later, alinidine was administered as a bolus dosage of 1 mg/kg in five dogs; the other five dogs served as a control group. RESULTS: Alinidine administration resulted in a decrease in HR from 157 +/- 20 to 138 +/- 27 beats/min (p less than .01) and a nonsignificant increase in cardiac output from 5.2 +/- 3.0 to 6.8 +/- 2.8 L/min, as a consequence of increases in stroke volume from 31.9 +/- 15.3 to 49.2 +/- 13.9 mL (p less than .01) and in left ventricular stroke work from 32.1 +/- 20.0 to 57.4 +/- 32.1 g.m (p less than .05). CONCLUSIONS: During experimental septic shock, alinidine administration can reverse dobutamine-induced tachycardia and simultaneously improve ventricular function.

Comparison of halothane, isoflurane, alfentanil, and ketamine in experimental septic shock.

The effects of four commonly used anesthetic agents, halothane, isoflurane, alfentanil, and ketamine, on cardiovascular function and oxygen balance were studied in a dog model of septic shock. After initial pentobarbital administration, the dogs were given Escherichia coli endotoxin (3 mg/kg) and, after 30 min, fluids to restore cardiac filling pressures to baseline levels. This resulted in a low resistance shock in all animals. Dogs were then given for 2 h either halothane (n = 9, 0.5 MAC), isoflurane (n = 9, 0.5 MAC), or alfentanil (n = 9, 150 micrograms/kg IV plus 2 micrograms.kg-1.min-1) or ketamine (n = 9, 2 mg/kg IV plus 0.2 mg.kg-1.min-1) or no anesthetic (control: n = 9). Mean arterial pressure increased in the control group (+11 +/- 18 mm Hg) and with ketamine (+10 +/- 20 mm Hg), remained unchanged with isoflurane (-2 +/- 11 mm Hg), and decreased with halothane (-22 +/- 23 mm Hg) and alfentanil (-9 +/- 23 mm Hg). Heart rate tended to increase in the control group but decreased with the four anesthetic agents, especially with alfentanil and halothane. Cardiac index and left ventricular stroke work index increased in the control group and in each anesthetic group except the halothane group. Systemic vascular resistance decreased in all groups except in the ketamine group. In the control group, the increase in cardiac index was associated with significant increases in oxygen delivery and consumption, and with a significant decrease in blood lactate levels. There was a dramatic decrease in oxygen consumption in all anesthetic groups, whereas oxygen delivery failed to increase only with halothane. Blood lactate increased significantly with halothane (5.0 +/- 1.5 to 6.3 +/- 1.4 mM/L) and isoflurane (4.8 +/- 1.1 to 5.3 +/- 1.2 mM/L), remained unchanged with alfentanil (4.5 +/- 1.5 and 4.6 +/- 0.8 mM/L), and tended to decrease with ketamine (4.9 +/- 1.4 to 4.5 +/- 1.4 mM/L). In conclusion, among the four anesthetic agents tested, halothane had the least desirable effects. Ketamine best preserved cardiovascular function and appeared to have the least deleterious effects on the hypoxic tissues. Thus, ketamine could be the anesthetic agent of choice in septic shock.

Dopamine compared with dobutamine in experimental septic shock: relevance to fluid administration.

The hemodynamic effects of dopamine and dobutamine (at doses of 6 micrograms X kg-1 X min-1) were compared during fluid resuscitation from septic shock induced by endotoxin (3 mg/kg) in the dog. In the first part of the study, when a standard amount of saline solution was infused (in 24 dogs), dopamine infusion resulted in higher cardiac filling pressures than did dobutamine infusion, whereas dobutamine infusion resulted in higher cardiac output. In the second part of the study, when fluid infusion was titrated to maintain pulmonary artery balloon-occluded pressure at constant level (in 24 dogs), the total amount of fluids was significantly greater with dobutamine than when dopamine was used (109 +/- 13 vs 71 +/- 10 ml/kg). The combination of dobutamine with fluids resulted in significantly greater stroke volume (39.6 +/- 3.8 vs 21.0 +/- 4.0 ml, P less than 0.05) and oxygen consumption (194 +/- 18 vs 144 +/- 8 ml/min, P less than 0.05). The different effects of dopamine and dobutamine on cardiac filling pressures can be due to differences in effects on myocardial contractility, ventricular afterload, and cardiac compliance. This experimental study indicates that when fluid therapy is combined with adrenergic agents in resuscitation from septic shock, dobutamine can be associated with higher cardiac output and oxygen transport and can result in higher tissue oxygen consumption than dopamine.

Hypophosphatemia after cardiothoracic surgery.

The incidence of hypophosphatemia during the first 48 h following cardiothoracic surgery was prospectively studied in 74 patients. Hypophosphatemia, defined by a serum phosphate below 2.50 mg/dl, was observed in 19 of 34 (56%) patients after thoracic surgery and in 20 of 40 (50%) patients after cardiac surgery. As a whole, hypophosphatemia occurred earlier after thoracic than after cardiac surgery. After thoracic surgery, hypophosphatemia was milder for patients in whom bleeding was more severe. The anticoagulant solution CPD used in stored blood was identified as an important source of phosphate. These results indicate hypophosphatemia is a common finding after cardiothoracic surgery. Since severe hypophosphatemia can be related to phosphate depletion, phosphate supplements could be warranted especially during thoracic surgery when blood transfusions are less than 1000 ml.