Epidural anaesthesia for caesarean section in a patient with a cerebral artery aneurysm.

A case is described of a 30-year-old insulin-dependent diabetic woman who presented at 25 weeks gestation with frontal headache. Contrast tomography revealed an aneurysm of the middle cerebral artery with no evidence of subarachnoid bleeding. Although elective caesarean section at term was planned, it was performed at gestational week 38 due to the onset of vaginal bleeding and premature labour. In contrast to previous reports, the cerebral aneurysm was not managed surgically at the same time as the delivery, but was treated conservatively. An epidural anaesthetic was performed successfully and postoperative analgesia maintained with a continuous infusion of local anaesthetic in the epidural space. Literature is reviewed and advantages of regional versus general anaesthesia are discussed.

Hyaluronan: relationship to hemodynamics and survival in porcine injury and sepsis.

BACKGROUND AND METHODS: Hyaluronan is a polysaccharide normally present in low concentrations in the blood, and is rapidly cleared from the blood by the liver. Increased plasma hyaluronan concentrations have been found in patients with sepsis. We studied changes in serum hyaluronan concentrations and their relationship to hemodynamics and survival in a 48-hr porcine model of injury and sepsis. RESULTS: Circulating hyaluronan concentrations increased to high values after induction of experimental sepsis (from mean baseline values of 242 +/- 26 [SEM] to mean maximum concentrations of 964 +/- 255 micrograms/L [p less than .01]) compared with controls (199 +/- 38 to 303 +/- 32 micrograms/L). A weak negative correlation between mean arterial pressure (MAP) and serum hyaluronan values was found (r2 = .47; p less than .01). Nonsurvivors had higher mean serum hyaluronan concentrations than survivors (603 +/- 147 vs. 285 +/- 43 micrograms/L [p less than .05]). CONCLUSIONS: Experimental sepsis is associated with an increase in serum hyaluronan values. The relationship between decreased MAP and increased serum hyaluronan concentrations could point to reduced liver perfusion as a cause. An association between high hyaluronan values and nonsurvival in sepsis is possible.

Influence of plasma protease activation on electroimmunoassay and nephelometry of plasma fibronectin in sepsis.

In vitro experiments have shown that proteases such as trypsin, kallikrein and plasmin may split plasma fibronectin, yielding changes in apparent mass concentration, i.e.: a decrease when using immunonephelometry (IN), and an increase when using electroimmunoassay (EIA). In the present in vivo study, plasma from 49 patients with severe infections was assayed for fibronectin by IN and EIA, and for prekallikrein, plasminogen and antithrombin. In patients with normal prekallikrein (n = 26) and plasminogen (n = 23), the agreement between the two fibronectin assay methods was good (ratio EIA/IN = 0.99 +/- 0.06); a similar good agreement was found in 45 healthy blood donors (ratio 0.97 +/- 0.02). In contrast, the 20 patients with low prekallikrein showed fibronectin values that were significantly higher by EIA than by nephelometry (ratio 1.27 +/- 0.10, p less than 0.01). Similarly, the 26 patients with low plasminogen had a significantly increased ratio (1.21 +/- 0.09, p less than 0.05). No such difference was seen, however, between patients with low or normal antithrombin. Thus, kallikrein and plasmin activation in vivo appear to increase the fibronectin concentration measured by EIA, possibly due to the formation of small fragments with increased electrophoretic motility.

Percutaneous, tunneled silicone elastomer central venous catheters for total parenteral nutrition: low sepsis and thrombosis rate. A prospective study of 315 catheters.

Silastic catheters were inserted by the percutaneous route, and tunneled subcutaneously, in 315 patients who needed venous access for total parenteral nutrition. The catheters were managed with a daily program that included heat sterilization of the metal hub with an electrical soldering iron. This study aimed to evaluate prospectively the incidence of catheter-related sepsis and thrombosis. There was one case of pneumothorax. All catheters were x-rayed post-insertion: eight catheters were malpositioned initially. The median catheter duration was 18 days with a range of 2-138 days. The total duration was 240 catheter-months. Twenty-seven catheters were removed due to mechanical problems. Nine were removed because of suspected sepsis; six patients had negative blood and catheter cultures, while three grew pathogens. The sepsis rate was thus 0.95%. There were no clinical signs of thrombosis. Pull-out venography was performed in 93 patients. Fibrin sleeves were seen in the majority of cases. Two patients had wall-adherent, non-occlusive thrombus masses (2%); they both had proximal catheter positions. We conclude that there is a low risk of catheter-related sepsis and thrombosis with this technique.

Elevated levels of plasma hyaluronan in septicaemia.

Hyaluronan (hyaluronic acid) is normally rapidly cleared from the circulation by the endothelial cells in the liver sinuoids, which make up part of the reticulo-endothelial system (RES). An impaired RES function in severe infection and sepsis might therefore lead to elevated hyaluronan plasma levels. Thus, plasma concentrations of hyaluronan were analysed in 44 patients with severe infection at onset of disease and twice during the following 2-3 days. The patients were divided with respect to severity of disease; no septic shock (n = 29), group 1), septic shock survivors (n = 7, group 2), and septic shock non-survivors (n = 8, group 3). Patients in group 1 showed significantly higher values of plasma hyaluronan on day 1 (p less than 0.05) compared with controls. There was no significant difference on the following two sampling occasions. Patients with septic shock (groups 2 and 3) showed higher values than both controls (p less than 0.001) and patients with severe infection without septic shock (group 1, p less than 0.001) at all three sampling occasions. Non-survivors of septic shock (group 3) had significantly higher values than survivors (group 2), (p less than 0.01-0.05). Septic shock, and especially fatal septic shock, thus appears to be associated with elevated plasma hyaluronan concentrations. Possible mechanisms might be an increased release of the polysaccharide from the interstitial space to the bloodstream, or a decreased rate of clearance by liver endothelial cells. This question demands further study.

Influence of epidural blockade on postoperative plasma fibronectin concentrations.

To investigate the influence of neurogenic and hormonal stimuli during and after surgery on plasma fibronectin levels, 16 females undergoing cholecystectomy were studied. Eight patients received general anaesthesia, and eight also received a thoracic epidural block with local anaesthetic, which was maintained for 24 h postoperatively. The epidural group had significantly lower plasma levels of adrenaline and cortisol than the general anaesthesia group in the postoperative period. The previously well-documented early decrease in plasma fibronectin concentration following surgery was observed, and was essentially parallel with that of albumin, pre-albumin and thyroid hormones, with no differences between the groups. However, the restoration of the fibronectin level was slower in the epidural group, with significantly lower values as compared with controls at 48 and 72 h after surgery (p less than 0.01-0.001). It was concluded that the post-traumatic plasma fibronectin decrease is not mediated by neurogenic or adrenal stimuli. Such stimuli may, however, influence the subsequent restoration of the plasma fibronectin concentration.

Cryoprecipitate infusion fails to improve organ function in septic shock.

Plasma fibronectin may be of critical importance for the septic patient through its proposed function as the major opsonin for macrophage clearance of circulating, noncellular debris. As a rule, critically ill, septic patients are depleted of fibronectin. In earlier uncontrolled studies, infusion of fibronectin-rich cryoprecipitate had resulted in improved renal and pulmonary functions and changes in peripheral hemodynamics. In this controlled study, 32 septic ICU patients (mean initial fibronectin level = 60% of normal) received cryoprecipitate or control infusions. Although the fibronectin level was significantly elevated to the normal range in the cryoprecipitate group, no effects were seen in hemodynamics, oxygen metabolism, or lung and kidney functions. Our results indicate that this form of fibronectin therapy does not influence the impaired organ function in septic shock.

A hemodynamic profile diagram and its application in septic patients.

A physiologic profile is presented in the form of a circular diagram, in which hemodynamic parameters, oxygen uptake and arterial lactate are displayed on 12 radial spokes. Results are presented as per cent of reference values. In the normal state the profile will be evenly circular, while different circulatory disturbances present typical patterns. This is shown in serial measurements on 12 septic patients, who displayed increases in cardiac output, oxygen metabolism, stroke volume, heart rate, pulmonary artery pressure, right atrial pressure, pulmonary capillary wedge pressure and arterial lactate, while pulmonary and systemic vascular resistances were decreased. Stepwise multiple regression analysis indicated that systemic vascular resistance was the best early discriminator between survivors and non-survivors. The hemodynamogram offers a compact and easily understood presentation of data, which makes it possible to follow the course of the disease and provides a diagnostic and didactic tool.

Fibronectin and other DIC-related variables in patients with moderately severe infections receiving cryoprecipitate.

Plasma fibronectin (Fn), a glucoprotein of suggested importance in host defence during infections also seems to be involved in blood coagulation and to be consumed during clot formation. Low Fn concentrations have been found in patients with DIC, but also in patients with infections without signs of overt DIC. In a randomized trial of Fn supplementation 28 patients with moderately severe infections, hospitalized in the Department for Infectious Diseases, were scheduled to receive either cryoprecipitate from 30 donors (n = 14) or 250-300 ml of stored plasma (n = 14). To elucidate the relationship between Fn plasma levels, Fn-rich cryoprecipitate infusion, and possible low-grade DIC in these patients, we measured platelet count, prothrombin complex (NT), fibrinogen, F V, F VIIIR:Ag, F VIII:C, F XII, plasminogen (Plg), antiplasmin (AP), antithrombin III (AT), kallikrein-inhibiting activity (KI) and spontaneous proteolytic activity (SPA). Compared to healthy controls, high initial values (p less than .001) were found for fibrinogen, F VIIIR:Ag, F VIII:C and SPA. Most values for platelets, F V, Plg, AP and KI were within the reference range. Low levels (p less than .001) were found for Fn, NT, F XII, AT and for the ratio F VIII:C/F CIIIR:Ag. A significant correlation was found between F XII, Plg and AT. Fn correlated poorly to the other variables. Cryoprecipitate infusion normalized the Fn concentration, but had no influence on other measured variables. Thus, although no patient had clinically overt DIC, and all survived, we observed a distinct pattern indicating activation of the coagulation system. Fn levels were low, but were not specifically related to this activation.

Fibronectin and other DIC-related variables in septic ICU patients receiving cryoprecipitate.

In a controlled study of fibronectin supplementation in sepsis, 11 ICU patients in septic shock were scheduled to receive either cryoprecipitate from 20-40 donors (n = 6) or 250-300 ml of stored plasma (n = 5) (two infusions over 24 h). We wanted to: compare some "conventional" DIC variables in the ICU (platelet count, prothrombin complex = NT, FDP) to additional variables: Fibronectin (Fn), fibrinogen (Fg), F V, FVIII R:Ag, F VIII:C activity, F XII, plasminogen (Plg), antiplasmin (AP), antithrombin (AT), kallikrein inhibiting activity (KI) and spontaneous proteolytic activity (SPA): study the effects of cryoprecipitate or plasma infusion on three variables. Samples were taken before the first infusion, and 24 and 48 h after. At onset, high levels (p less than .001 when compared to blood donors) of Fg, VIIIR:Ag and VIII:C were seen. KI levels were within the normal range. F V was low (p less than .05). Fn, NT, XII, Plg, AP and AT were markedly low (p less than .001). SPA showed great variation. When compared to 28 patients with severe infections, but not in septic shock, the ICU group had higher VIIIR:Ag (p less than .05) and VIII:C (p less than .01), and lower XII, Plg, AP and AT (p less than .001). FDP was elevated in all ICU patients. Five patients were thrombocytopenic, and in these a pattern with low levels of Plg and AT was observed. Fn did not correlate well to the other variables measured. These results indicate a marked activation of coagulation and fibrinolysis in these severely ill patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Gas exchange during mechanical ventilation.

In an experimental model using a Servo-ventilator (Siemens-Elema, Sweden) oxygen consumption (V'O2) and carbon dioxide production (V'CO2) were measured at varying FIO2. Gas exchange was simulated by adding N2 or CO2 to the inspiratory line of the ventilator. Inspiratory and expiratory gases were collected in Douglas bags for analyses by a mass spectrometer. The residual standard deviation for the regression of measured V'O2 on predicted V'O2 was 14 ml/min and did not significantly differ from the line of identity. For V'CO2 the corresponding residual standard deviation was 3 ml/min. This regression line deviated by -3% from the line of identity.

Decrease of plasma fibronectin concentration following infusion of a gelatin-based plasma substitute in man.

Intravenous infusion of 500 ml of a gelatin-based plasma substitute, Haemaccel, given to healthy volunteers, resulted in a significant decrease of the immunoreactive plasma fibronectin concentration 48 h and 72 h after infusion. One hour after infusion, the ability of fibronectin to bind gelatin was inhibited with a gradual recovery within 48 h. A dextran based plasma substitute, Macrodex, did not have this effect on plasma fibronectin.

Long term parenteral therapy by percutaneous tunneled silicone central venous catheter--a follow-up of 300 catheters.

We have developed a technique for the management of central venous catheters which incorporates percutaneous insertion and daily care for routine use in different wards. A follow-up of the first 300 catheters is presented. When intravenous therapy was planned for more than two weeks, a silicone rubber catheter was introduced percutaneously with a skin tunnel and the position of the tip in the lower superior vena cava checked by venous pressure measurement. The metal hub of the catheter was disinfected daily by heating with a modified soldering iron which has been proved to be effective by in vitro testing with different microorganisms. The external jugular vein was used in 164 cases (55 per cent) the internal jugular vein in 115 (38 per cent) and the remaining catheters were inserted by the subclavian or antecubital route. Correct positioning was obtained in 96 per cent and serious early or late complications were rare there being only one case of septicaemia in a total treatment period of 270 months. One patient developed a lung infarct, but no case of pneumothorax has been seen. The mean duration of the catheters was 27 days (range 1-239) and the common reasons for termination were cessation of need in 84 per cent, mechanical obstruction in 6 per cent and inadvertent removal in 6 per cent. The described method has proved to be safe and to function well on ordinary wards.