Inhaled nitric oxide reduces pulmonary transvascular albumin flux in patients with acute lung injury

BACKGROUND

In acute lung injury, when pulmonary microvascular permeability is enhanced, transvascular fluid filtration mainly depends on pulmonary capillary pressure. Inhaled nitric oxide has been shown to decrease pulmonary capillary pressure. Therefore, the effect of inhaled nitric oxide at a concentration of 40 ppm on pulmonary transvascular albumin flux was studied in nine patients with acute lung injury.

METHODS

Transvascular albumin flux was measured by a double radioisotope method using 99mTc-labeled albumin and 51Cr-labeled autologous red blood cells. Radioactivity of both isotopes was externally measured over the right lung by a gamma scanner and simultaneously in arterial blood. The normalized ratio of 99mTc/51Cr lung to 99mTc/51Cr blood (normalized index) was calculated. The normalized slope index which is the slope of the regression line of the normalized index versus time represents the accumulation rate of albumin in the interstitial space of the lungs. Normalized slope index and pulmonary capillary pressure were determined before, during, and after inhalation of 40 ppm nitric oxide. Pulmonary capillary pressure was estimated using the visual analysis of the pressure decay curve after pulmonary artery occlusion.

RESULTS

Normalized slope index decreased from 0.0077 +/- 0.0054 min-1 (SD) off nitric oxide to -0.0055 +/- 0.0049 min-1 (P < 0.01) during nitric oxide and increased to 0.0041 +/- 0.0135 min-1 after nitric oxide. Pulmonary capillary pressure declined from 24 +/- 4 mmHg off nitric oxide to 21 +/- 4 mmHg during nitric oxide (P < 0.01), whereas pulmonary artery wedge pressure and cardiac output did not change.

CONCLUSIONS

It is concluded that 40 ppm inhaled nitric oxide decreases pulmonary transvascular albumin flux in patients with acute lung injury. This effect may be the result of the decrease in pulmonary capillary pressure.

Differential effects of dobutamine, dopamine, and noradrenaline on splanchnic haemodynamics and oxygenation in the pig

Supranormal oxygen (O2) transport may benefit critically ill patients. Catecholamines are clinically employed for this purpose. However, their effects on splanchnic haemodynamics and oxygenation are now well defined. The effects of dobutamine (DOBU), dopamine (DOPA), and noradrenaline (NA) on splanchnic blood flows electromagnetic flow probes), O2 deliveries and uptakes (catheterisation of portal and hepatic veins) were studied in nine anaesthetised (ketamine/flunitrazepam), ventilated, paralysed, and laparotomised pigs. All three catecholamines (DOPA at 15 micrograms.kg-1.min-1, DOBU at 13 micrograms.kg-1.min-1, NA at 0.4 micrograms.kg-1.min-1) significantly (P < 0.05) increased cardiac output and systemic O2 delivery. Only DOPA increased small intestinal and total hepatic blood flows, and O2 deliveries, and decreased O2 extractions. The same parameters did not change during DOBU. During NA, total hepatic blood flow and O2 delivery decreased, and hepatic O2 extraction increased. During all three catecholamines, small intestinal and total hepatic O2 uptakes did not change significantly. Whereas hepatic arterial blood flow decreased during both DOPA and NE, portal venous flow increased during DOPA. These data suggest that in the experimental model used splanchnic O2 supply and O2 reserve capacity appear improved by DOPA, unaffected by DOBU, and impaired by NA.

Local production of IFN-gamma abrogates the intraocular immune privilege in transgenic mice and prevents the induction of ACAID

The eye represents an immunologically privileged site with specific properties mediated by immunosuppressive constituents of the intraocular fluids. This system, termed ACAID (anterior chamber-associated immune deviation), was originally attributed to the anterior chamber of the eye, and is characterized by impairment of the cellular immune response, including a lack of delayed type hypersensitivity (DTH) reaction in response to intraocularly presented Ag and decreased cytotoxicity of T cells. We created a transgenic mouse with ectopic expression of IFN-gamma in the photoreceptors of the retina to study the effects of this cytokine on the immunosuppressive properties of the eye with special regard to the posterior chamber. BALB/c-derived transgenic and nontransgenic mice were challenged intravitreally either with allogeneic splenocytes from C57Bl/6 mice or with BSA, in IFA, and tested for the delayed type hypersensitivity reaction to BSA by intrapinnal injection of the same Ag in the ear 7 days later. Pathologic changes of the eyes were evaluated by histology and immunohistochemistry. We found that transgenic mice developed an increased amount of ocular inflammation in response to both Ags compared with the nontransgenic controls. Furthermore, transgenic mice showed a marked DTH reaction to BSA, whereas nontransgenic mice did not. Our results indicate that local IFN-gamma production disturbs the immunosuppressive properties of the eye and prevents the induction of ACAID in response to intraocularly presented Ag. The data confirm the extension of the intraocular immune privilege to the posterior chamber of the eye.

Local production of IFN-gamma abrogates the intraocular immune privilege in transgenic mice and prevents the induction of ACAID

The eye represents an immunologically privileged site with specific properties mediated by immunosuppressive constituents of the intraocular fluids. This system, termed ACAID (anterior chamber-associated immune deviation), was originally attributed to the anterior chamber of the eye, and is characterized by impairment of the cellular immune response, including a lack of delayed type hypersensitivity (DTH) reaction in response to intraocularly presented Ag and decreased cytotoxicity of T cells. We created a transgenic mouse with ectopic expression of IFN-gamma in the photoreceptors of the retina to study the effects of this cytokine on the immunosuppressive properties of the eye with special regard to the posterior chamber. BALB/c-derived transgenic and nontransgenic mice were challenged intravitreally either with allogeneic splenocytes from C57Bl/6 mice or with BSA, in IFA, and tested for the delayed type hypersensitivity reaction to BSA by intrapinnal injection of the same Ag in the ear 7 days later. Pathologic changes of the eyes were evaluated by histology and immunohistochemistry. We found that transgenic mice developed an increased amount of ocular inflammation in response to both Ags compared with the nontransgenic controls. Furthermore, transgenic mice showed a marked DTH reaction to BSA, whereas nontransgenic mice did not. Our results indicate that local IFN-gamma production disturbs the immunosuppressive properties of the eye and prevents the induction of ACAID in response to intraocularly presented Ag. The data confirm the extension of the intraocular immune privilege to the posterior chamber of the eye.

Inhaled nitric oxide lowers pulmonary capillary pressure and changes longitudinal distribution of pulmonary vascular resistance in patients with acute lung injury

In acute lung injury (ALI), where pulmonary microvascular permeability is increased, transvascular fluid filtration depends mainly on the hydrostatic capillary pressure. In the presence of intrapulmonary vasoconstriction pulmonary capillary pressure (PCP) may increase thereby promoting transvascular fluid filtration and lung oedema formation. We studied the effect of 40 ppm inhaled nitric oxide (NO) on PCP and longitudinal distribution of pulmonary vascular resistance (PVR) in 18 patients with ALI. PCP was estimated by visual analysis of the pressure decay profile following pulmonary artery balloon inflation. Contribution of venous pulmonary resistance to total PVR was calculated as the percentage of the pressure gradient in the pulmonary venous system to the total pressure gradient across the lung. Inhalation of 40 ppm NO produced a prompt decrease in mean pulmonary artery pressure (PAP) from 34.1 +/- 6.8 to 29.6 +/- 5.7 (s.d.) mmHg; (P < 0.0001). PCP declined from 24.8 +/- 6.2 to 21.6 +/- 5.2 mmHg; (P < 0.0001) while pulmonary artery wedge pressure (PAWP) did not change. PVR decreased from 166 +/- 73 to 128 +/- 50 dyn.sec.cm-5; (P < 0.0001). Pulmonary venous resistance (PVRven) decreased to a greater extent (from 76 +/- 41 to 50 +/- 28 dyn.sec.cm-5; (P < 0.001) than pulmonary arterial resistance (PVRart) (from 90 +/- 36 to 79 +/- 29 dyn.sec.cm-5; (P < 0.01). The contribution of PVRven to PVR fell from 44.3 +/- 10.8 to 37.8 +/- 11.9%; (P < 0.01). Cardiac output (CO) remained constant. The findings demonstrate that NO has a predominant vasodilating effect on pulmonary venous vasculature thereby lowering PCP in patients with ALI.

Ectopic expression of gamma interferon in the eye protects transgenic mice from intraocular herpes simplex virus type 1 infections

Transgenic (rho gamma) mice provide a model for studying the influence of gamma interferon (IFN-gamma) produced in the eye on ocular and cerebral viral infection. To establish this model, we injected BALB/c- and C57BL/6-derived transgenic and nontransgenic mice of different ages intravitreally with herpes simplex virus type 1 (HSV-1) strain F. Eye and brain tissues of these mice were assessed for pathological and immunocytochemical changes. HSV-1 infection induced severe retinitis of the injected eyes and infection of the brain in all mice. In transgenic mice inoculated with HSV-1, the left, nontreated eyes were protected from retinitis, whereas nontransgenic mice developed bilateral retinitis. Additional intravitreal injection of IFN-gamma with the virus protected the noninoculated eyes of nontransgenic mice. Three-week-old nontransgenic mice died from HSV-1 infection, whereas transgenic mice of the same age and nontransgenic mice intravitreally treated with IFN-gamma survived. Ocular IFN-gamma production increased the extent of inflammation in transgenic mice but did not have a significant influence on the growth of HSV-1 until day 3 after inoculation and did not influence the neuroinvasion of this virus. Thus, the effects of IFN-gamma were not caused by an early block of viral replication. Possible mechanisms of IFN-gamma action include activation of the immune response, alteration of the properties of the virus, and direct protection of neurons.

Transgenic mice expressing IFN-gamma in the retina develop inflammation of the eye and photoreceptor loss

PURPOSE

Inflammatory mediators such as interferon-gamma (IFN-gamma) are thought to play a role in ocular disease. Although IFN-gamma was found in the vitreous of mice with experimentally induced autoimmune uveitis, intracameral injection of this cytokine did not induce intraocular inflammation in mice. Therefore, the authors created a transgenic mouse line using the rhodopsin promoter to direct the expression of IFN-gamma in the photoreceptor cells of the retina. These mice, designated rho gamma, enabled them to model intraocular inflammatory disease.

METHODS

The authors fused a 2.1 kb 5' Hind III fragment from the murine rhodopsin gene to the IFN-gamma gene and introduced the DNA construct into fertilized zygotes. These were implanted into pseudopregnant C57BL/6 mice, and the resulting progeny were crossed back to balb/c mice. The transgene was identified by Southern blot hybridization. Eyes from the rho gamma mice were either fixed in zinc formalin and stained with hematoxylin and eosin or were frozen in OCT compound and processed for immunostaining using the indirect immunoperoxidase method with DAB as a chromogen.

RESULTS

The rho gamma transgenic mice developed intraocular disease, manifested as intraocular cellular infiltration, loss of photoreceptors, corneal clouding, cataract formation, and epithelial and microglial proliferation. Additionally, rho gamma mice exhibited antigenic changes, comprising GFAP expression on Müller cells, accumulation of neurofilament on photoreceptors, and expression of MHC class I and class II molecules on retinal cells.

CONCLUSIONS

IFN-gamma alters the antigenic properties of intraocular tissue and induces intraocular inflammation in mice. The results suggest a key position of IFN-gamma in the development of pathologic conditions related to intraocular inflammation and provide a useful animal model for the further study of inflammatory disorders, including autoimmune diseases.

Relationship of plasma epinephrine and circulating eosinophils to nocturnal asthma

The mechanisms of nighttime airway obstruction are not fully established, but include circadian fluctuations in epinephrine and cortisol. To evaluate the relationship of circadian patterns in epinephrine and cortisol to nighttime airflow obstruction, 10 young adult asthma patients (ages 19 to 25 yr) were admitted to a hospital clinical research unit for a 3-day study during which plasma concentrations of epinephrine, cortisol, and histamine were determined along with white blood cell and eosinophil counts every 6 h (1600, 2200, 0400, and 1000 h). Six of the 10 patients experienced at least one episode of nocturnal asthma (defined by more than a 15% decrease in antemeridian (A.M.) to postmeridian (P.M.) FEV1 values). Plasma epinephrine levels (pg/ml) showed a circadian pattern, and the concentration at 2200 h was significantly (p = 0.039) different for the nocturnal and non-nocturnal asthma groups. Circulating eosinophil numbers were greater in subjects who had more frequent episodes of nocturnal asthma, and correlated with the frequency of nocturnal asthma (r = 0.732, p = 0.02, Spearman rank correlation) and average percent decrease in FEV1 (r = 0.667, p = 0.035). Plasma cortisol concentrations also showed circadian patterns, but no direct association with nocturnal asthma; plasma histamine concentrations showed no circadian patterns and no association with nocturnal asthma. Our findings indicate that changes in plasma epinephrine precede the development of nocturnal airway obstruction and contribute to the likelihood of nighttime airflow obstruction.

[Long term course of catecholaminergic polymorphic ventricular tachycardia in children. Apropos of 20 cases with an 8 year-follow-up]

BACKGROUND

Primary ventricular arrhythmias are rarely seen in children. Some of them have a poor prognosis; they should be diagnosed because adequate treatment can prevent sudden death.

POPULATION AND METHODS

Twenty children (11 male, nine female), aged 3 to 16 years (mean: 7.7 +/- 4), with apparently normal hearts and normal QTc intervals were referred for stress or emotion-induced syncope. Primary ventricular arrhythmia, consisting of isolated polymorphic ventricular extrasystoles followed by salvos eventually degenerating into ventricular fibrillation, was reproducibly induced by physical exertion. The syncopal events and "torsades de pointe" disappeared with beta-blocking therapy. A total of four syncopal events and two sudden deaths occurred during a mean follow-up of 8 years, probably due to discontinuation of treatment.

DISCUSSION

Fifty-four-cases of stress-induced severe polymorphous ventricular arrhythmia have been reported in the literature. There were four sudden deaths in 37 patients on beta-blocking therapy, and ten sudden deaths in 21 untreated patients.

CONCLUSION

Clinically close to the congenital long QT syndrome, this primary ventricular arrhythmia must be looked for in cases of stress or emotion-induced syncope. The diagnosis relies on Holter monitoring and a stress test. Life-long beta blocker therapy is required.

Paraffin induced sclerosing lipogranuloma of eyelids and anterior orbit following endonasal sinus surgery

During the past 5 years we have seen 10 patients who had developed sclerosing lipogranuloma of the lid and orbit after endonasal sinus surgery with subsequent ipsilateral monocular haematoma. The histopathological examination of all and the additional nuclear magnetic resonance spectroscopic examination of four surgical specimens in combination with the typical clinical course led to the conclusion that the granulomas were caused by small paraffin droplets. These in turn stemmed from the ointment plugs applied to the sinuses at the end of the operation, and were washed out into the surrounding tissues by the postoperative haemorrhage. As the chronic and recurring granulomas can lead to considerable cosmetic and functional impairment, the application of ointment plugs at the end of sinus surgery should be abandoned, especially when peri- or postoperative bleeding occurs.

[Chronic lipogranuloma (paraffin granuloma) of the eyelids and orbits after endonasal paranasal sinus operation]

During the last five years 10 patients received surgical treatment in our eye clinic for tumours of the eyelids and the orbit that had developed after endonasal sinus surgery. In most patients the first signs of lid or orbital involvement had occurred 4 weeks after ENT surgery and after a unilateral or bilateral postoperative haematoma had subsided. The histological examination of the surgical specimens showed chronic sclerosing lipogranuloma containing large vacuoles surrounded by epithelioid and giant cells, typical of a so-called paraffin granuloma. MR-spectroscopy detected high concentrations of paraffin in the specimens of 3 patients. Since paraffin is a constituent of many ointments, we assume that the granulomatous reaction was elicited by the ointment tampons routinely applied to the wound area following sinus surgery. The bleeding acted as a vehicle to distribute the paraffin into the surrounding tissues.

Exogenous or endogenous reservoirs of nosocomial Pseudomonas aeruginosa and Staphylococcus aureus infections in a surgical intensive care unit

OBJECTIVE

A 4 month prospective study was performed to assess the incidence and routes of endogenous or exogenous colonization and nosocomial infection caused by Staphylococcus aureus and Pseudomonas aeruginosa in surgical critically ill patients.

DESIGN

A total of 4634 specimens were obtained. Patient's nasal, scalp, and rectal swabs as well as tracheal secretion (TS) were cultured every second day beginning on the day of admission. Nasal swabs and hand cultures of the personnel as well as cultures from gowns were also taken. All isolates of S. aureus were phage typed and 116 of these isolates were also plasmid typed. P. aeruginosa isolates were sero- and pyocin typed. Resistance patterns were determined in all isolates.

SETTING

The study was carried out in the surgical intensive care unit (SICU) of an teaching hospital.

PATIENTS

During the study period each patient (a total of 153 patients) admitted to the SICU entered the study.

RESULTS

P. aeruginosa and S. aureus colonisation rate on admission were 5% and 36.5% respectively. Only 10 patients (6.5%) were colonized with P. aeruginosa during hospitalization, and only 7 patients (4.5%) acquired S. aureus in the surgical intensive care unit (SICU). The most common primary colonisation site of P. aeruginosa was the rectum, whereas S. aureus was predominantly found in nasal cultures. Horizontal transmission of S. aureus occurred in only 2 patients.

CONCLUSION

The study suggests that colonisation with P. aeruginosa and S. aureus occurs from endogenous rather than from exogenous sources and that the endogenous acquisition of both bacteria play a more important role in development of nosocomial infections than the exogenous route of transmission.

[Inhaled nitric monoxide. Application and continuous measurement of concentration]

Inhaled nitric oxide (NO) is a selective pulmonary vasodilator that may be useful in the treatment of patients with severe pulmonary hypertension. We describe a delivery system of inhaled NO that allows safe application and continuous measurement of the inspired NO concentration during mechanical ventilation. From a gas cylinder containing NO in N2 (600 ppm NO), an adjustable amount of gas is introduced into the inspiratory side of the tubing system via a pressure reduction valve, a magnetic valve, and a special injection nozzle. The NO concentration is diluted to the desired value by the tidal volume. The magnetic valve is connected to the ventilator and opens at the beginning of each inspiration and closes after a predetermined time. The gas volume is proportional to the pressure at the magnetic valve and the opening time. To monitor the inspiratory NO concentration, a specimen of gas is taken from an angle-connector and passed over an electrochemical sensor. The second nozzle of the sensor is connected to a water seal, which is adjusted to the positive end-expiratory pressure level of the ventilator to insure that the gas flow over the sensor is limited to inspiration.

Enhancement of in vitro bactericidal activity of neutrophils from trauma patients in the presence of granulocyte colony-stimulating factor

In order to determine whether granulocyte colony-stimulating factor (G-CSF) can enhance the bactericidal activity of polymorphonuclear leukocytes (PMNL) in trauma patients, PMNL obtained from severely injured patients one or two days after trauma were incubated with G-CSF and Staphylococcus aureus for different periods of time. G-CSF at a concentration of 6000 units/ml significantly improved the antibacterial activity of PMNL in trauma patients (n = 10) and healthy volunteers (n = 12) during the incubation period of 180 min. No difference in the bactericidal function of PMNL could be found between severely injured patients and healthy donors.

Splanchnic hemodynamics and oxygen supply during acute normovolemic hemodilution alone and with isoflurane-induced hypotension in the anesthetized pig

Safety of combined hemodilution and isoflurane-induced hypotension was assessed by studying their effects on splanchnic hemodynamics and oxygenation in nine anesthetized (ketamine/flunitrazepam) pigs. Acute normovolemic hemodilution (decrease in hematocrit from 29% to 15%) with 6% hydroxyethyl starch decreased (P < 0.05) O2 delivery despite increases in cardiac output and all splanchnic flows, as measured by electromagnetic flow probes. Superimposed isoflurane (1.45% end-tidal concentrations) caused marked decreases in arterial blood pressure, cardiac output, and splanchnic flows. Oxygen uptake of the liver became O2 supply dependent. A liver surface PO2 histogram (Clark-type electrode) showed 38% of PO2 values between 0 and 5 mm Hg. Hepatic lactate uptake decreased by 75%. These data suggest that depression of cardiovascular function during reduced O2-carrying capacity adversely affects hepatic perfusion, oxygenation, and function. Combined hemodilution and isoflurane-induced hypotension may not be appropriate in patients.

Prolongation of hospital stay and extra costs due to ventilator-associated pneumonia in an intensive care unit

A prospective cohort study was performed to determine the prolongation of stay and the extra costs incurred due to the occurrence of ventilator-associated pneumonia in intensive care unit patients. Over a 16-month period a sample of 270 consecutive adult patients from a large university anesthesiological intensive care unit requiring ventilation therapy for more than 24 hours was analyzed. A matching procedure using multiple control patients without pneumonia per infected patient (= case) was employed. Of 78 cases 21 (26.9%) died and were excluded from the matching procedure as well as 23 (29.5%) for whom suitable controls could not be found. The maximum number of controls per case was five. The mean added stay was calculated to be 10.13 days and the extra costs attributable to the prolongation of stay were 14,253 German Marks (US$8,800) per patient, demonstrating considerable added stay and costs due to ventilator-associated pneumonia acquired during intensive care. However, it should be taken into account that the calculations for excess stay and costs are based on a subset of rather ill patients and thus cannot generally apply to all ventilated patients and that cases were excluded which could not be matched.

Platelet-activating factor primes human eosinophil generation of superoxide

Platelet-activating factor (PAF) is a potent inflammatory mediator that can cause airway obstruction and hyperresponsiveness; these processes are also associated with pulmonary eosinophilia, suggesting a link between these two events. Thus, PAF's interaction with eosinophils may provide a mechanism for airway damage. However, direct in vitro activation of eosinophils by PAF requires concentrations that are likely higher than those achieved in vivo. As a result, we investigated whether lower, more physiologic concentrations of PAF could prime eosinophils for subsequent activation to another receptor-stimulated factor, in this case formylmethionylleucylphenylalanine (FMLP). To test this hypothesis, eosinophils were preincubated (1 and 15 min) with low concentrations of PAF (1 x 10(-8) and 1 x 10(-10) M); this exposure to PAF resulted in enhanced generation of superoxide anion to FMLP stimulation. Moreover, similar concentrations of PAF decreased eosinophil density and increased expression of cell surface CR3 receptors. Finally, low, nonactivating concentrations of PAF (1 x 10(-10) to 1 x 10(-8) M) caused transient increases in eosinophil cytosolic free Ca2+ concentrations. Collectively, these responses are consistent with the hypothesis that short-term exposure to low concentrations of PAF primes eosinophils to cause an enhanced inflammatory response upon subsequent activation to another receptor agonist. The consequences of this PAF-associated phenomenon can produce an enhanced inflammatory response and airway injury.

Incidence of pneumonia in mechanically ventilated patients treated with sucralfate or cimetidine as prophylaxis for stress bleeding: bacterial colonization of the stomach

Retrograde colonization of the oropharynx from the stomach by microaspiration of gastric fluid is a recently recognized phenomenon associated with increased gastric pH that may result in pneumonia during ventilation therapy. In a prospective study we investigated 104 mechanically ventilated patients in the intensive care unit who were receiving sucralfate (n = 49) or cimetidine (n = 55) for stress ulcer prophylaxis. The incidence of pneumonia was 45.5% (25 patients) in the cimetidine group and 26.5% (13 patients) in the sucralfate group (95% confidence interval 0.98 to 6.97; odds ratio 2.61; p = 0.0549). Mortality rates were 18.4% (9 patients) in the sucralfate group versus 25.5% (14 patients) in the cimetidine group (p = 0.48). The mean pH values of gastric aspirates were significantly lower in patients treated with sucralfate than in patients receiving cimetidine (p = 0.044). The number of colony-forming units of Enterobacteriaceae in gastric aspirates was also significantly lower in the sucralfate group (p = 0.0037).

Effects of acute normovolemic hemodilution on splanchnic oxygenation and on hepatic histology and metabolism in anesthetized pigs

Perioperative hemodilution (HD) has become an accepted means of reducing transfusion requirements. Therefore, the effects of limited (decrease in hematocrit [Hct] from 30 to 20%, "HD1") and severe (decrease in Hct from 20 to 14%, "HD2") acute normovolemic HD with 6% hydroxyethyl starch on splanchnic blood flows (electromagnetic flow probes), O2 uptakes and deliveries, surface O2 tensions (PO2) (Clark-type electrode), hepatic metabolism (organic acids), and hepatic histology (liver biopsies) were studied in nine pigs anesthetized and paralyzed with ketamine/flunitrazepam and pancuronium. HD1 caused significant (P less than 0.05) increases in cardiac output and all splanchnic flows. Only hepatic arterial blood flow increased twice as much as did cardiac output. Except for hepatic arterial O2 delivery, all splanchnic O2 deliveries decreased. Splanchnic O2 extractions increased, and O2 uptakes remained unchanged. There were no changes in mean surface PO2 values or in surface PO2 histograms of liver and small intestine; in portal or hepatic venous pH; and in hepatic uptake of pyruvate and lactate. In contrast, during HD2 (despite further increases in flows and O2 extractions) portal and hepatic venous pH decreased; mean surface PO2 of liver and small intestine decreased; and the liver surface PO2 histogram showed broadening and a shift to the left. However, hepatic uptake of lactate and pyruvate, and splanchnic O2 uptake remained unchanged, and histologic examination did not reveal significant cell injury. These data indicate that in this experimental model limited acute normovolemic HD was well tolerated by the splanchnic organs. After severe HD, gross liver function remained intact, but there was evidence that compensatory mechanisms (increases in flow and O2 extractions) were no longer fully able to counteract the decrease in splanchnic O2 delivery.

[Prolongation of hospital stay by nosocomial pneumonia and wound infection]

From June 1988 to September 1989, a prospective survey comprising a total of 1183 patients in a university hospital was carried out to ascertain the additional length of stay in intensive care units because of nosocomial pneumonia associated with artificial ventilation (418 patients, 296 men, 122 women, mean age 48.8 +/- 21 years, ventilated for more than 24 h) or by postoperative wound infections (765 patients, 501 men, 264 women, mean age 60 +/- 11 years, after operations on the large bowel, heart or biliary tract). Each patient with a nosocomial infection was matched against a variable number of control patients (for cases of pneumonia a maximum of 6, for wound infections a maximum of 10) without nosocomial infection. Pneumonia developed in 100 (23.9%) of artificially ventilated patients, and 46 of these patients together with 101 controls were entered into the matching procedure. 24 patients with pneumonia had to be excluded from analysis because no controls could be found for them, and also 30 patients who died while in the intensive care unit. 49 (6.4%) of the surgical patients contracted postoperative wound infections. 43 of them, together with 210 controls, were entered into the matching procedure. Among patients with pneumonia the average additional duration of stay was 11.5 days, and among patients with post-operative wound infections it was 13.9 days. The results confirm that nosocomial infections contribute substantially to prolongation of hospital stay and hence to the costs.

[The effect of 6% (40/0.5) hydroxyethyl starch and Ringer's lactate on blood coagulation, laboratory parameters and circulation during peridural anesthesia]

We investigated the effects of 6% hydroxyethyl starch (HES 40/0.5) and lactated Ringer solution (LRS) on blood coagulation tests and laboratory parameters during epidural anesthesia. Additionally, the efficacy of this prophylactic intravenous fluid supply in preventing sympathetic blockade induced hypotension was studied. METHODS. A single shot lumbar epidural block was given to 55 patients using 14-18 ml of bupivacaine 0.75%. The patients were randomized to receive either 1000 ml 6% HES 40/0.5 or 1000 ml LRS starting 5 min before the epidural blockade was set. The first 500 ml was infused during a 15-min period and the remaining 500 ml solution during the next 30 min. Cardiovascular parameters were recorded and blood samples were taken 30, 60, 120 and 240 min after the start of the infusion. RESULTS. No significant differences were found in the cardiovascular parameters, although in patients with a cranial spread of epidural blockade above T 10, patients who received LRS showed more episodes of severe hypotension. Serum osmolarity, potassium and sodium remained constant throughout the observation period. HES 40/0.5 caused a significantly greater hemodiluting effect than LRS, which was evident in more pronounced temporary decreases in serum protein concentration, hemoglobin concentration, hematocrit, fibrinogen and platelets. In coagulation parameters LRS caused no changes of PTT and Quick, whereas HES 40/0.5% led to a significant prolongation of PTT and a decrease in Quick. CONCLUSION. Fluid supply with either LRS or 6% HES 40/0.5 cannot prevent the epidural blockade induced hypotension entirely. In epidural anesthesia with spread of blockade above T 10, 6% HES 40/0.5 is superior to LRS in the prevention of severe hypotension. The temporary increase in plasma volume after infusion of 6% HES 40/0.5 results in a greater hemodilution with a concomitant decrease of blood viscosity and improved microcirculation flow. These might be of interest in prevention of thromboembolic complications. The specific effects of the two solutions were also determinable during epidural blockade.

Differences in effects of isoflurane and enflurane on splanchnic oxygenation and hepatic metabolism in the pig

The effects of end-tidal concentrations of 1.45% isoflurane and 2.12% enflurane on splanchnic blood flow (electromagnetic flow probes), oxygen (O2) extraction and surface PO2 (Clark-type electrode), and hepatic metabolism (organic acids) were compared in an animal model relevant to humans. Eighteen laparotomized, ventilated pigs, anesthetized and paralyzed with ketamine/flunitrazepam and pancuronium, were studied. Enflurane caused significantly (P less than 0.05) greater decreases in mean arterial pressure, cardiac output, and superior mesenteric arterial, portal, and total hepatic blood flows. In addition, hepatic arterial blood flow decreased during enflurane administration but increased markedly (40%) during isoflurane administration. However, mean surface PO2 of liver and small intestine decreased to similar degrees (20%) during isoflurane and enflurane. Summary histograms of surface PO2 values were leftward shifted but did not show O2 values in the hypoxic range (0-5 mm Hg). Except for a decrease in hepatic lactate uptake during enflurane, there were no changes in either hepatic uptake or release of organic acids during anesthesia with either agent. These data show that splanchnic O2 supply is better maintained during isoflurane than during enflurane. Although this was not reflected in differences in tissue oxygenation and metabolism, decreased portal and hepatic venous O2 contents during enflurane indicate that an increase in preportal and hepatic oxygen extraction was necessary to preserve tissue oxygenation.

Influence of architectural design on nosocomial infections in intensive care units--a prospective 2-year analysis

Nosocomial infection rates in an old intensive care ward constructed in 1924 were compared with those in a new one constructed in 1986. The nosocomial infection rate in the old unit was 34.2% and that in the new unit 31.9%, with an average of 33%. The most frequent infections were: pneumonia, urinary tract infection, septicaemia and wound infection. After transfer of the intensive care unit (ICU) the incidence and profile of nosocomial infections remained the same. These findings suggest that the influence of architectural design has little impact on the incidence of nosocomial infections.

[Anesthesia in bronchial asthma]

Between 2% and 5% of the population suffer from bronchial asthma. The disease is characterized by bronchial hyperreactivity to physical, chemical, pharmacological, and/or immunological irritants. The incidence of perioperative complications is higher in asthmatics than in non-asthmatics. Careful pre- and postoperative care can reduce complications in these patients. Successful management of an asthmatic patient undergoing anesthesia starts with the identification of patients with asthma, the preoperative assessment, and evaluation of the pulmonary function. No elective surgery should be performed in patients suffering from unstable asthma or an acute attack. Thorough knowledge of the effects and interactions of broncholytic therapy with anesthesia is mandatory. Preanesthetic management must take into consideration the etiology of the disease; intraoperatively, attention must be paid to the pathophysiology. Appropriate perioperative monitoring can help to prevent complications. No one type of anesthesia is associated with lower postoperative complications. The skill of the anesthesiologist, early recovery from general anesthesia, and good postoperative care greatly reduce the incidence of complications. Besides the changes in pulmonary function that occur following anesthesia and surgery, asthmatics may suffer from abnormalities in control of ventilation and mucociliary function postoperatively. The patient with a history of asthma needs close supervision during the postoperative period: many sudden deaths from asthma and many episodes of ventilatory arrest occur during the night and in the early morning.

[Metabolism-oriented postoperative nutritional therapy--possibilities and limits in the use of glucose and xylitol]

Carbohydrates and polyols are essential constituents of intravenous nutrition. In order to better understand the problems associated with the supply of energy sources, the physiology of enteral nutrition will be covered and compared with intravenous nutrition. This review article will deal with the metabolic actions of glucose and xylitol and derive therapeutical consequences for their intravenous use during different illnesses.

Side effects of positive pressure ventilation on hepatic function and splanchnic circulation

Positive pressure ventilation is associated with a reduction and redistribution of cardiac output. Splanchnic blood flow is decreased. Blood supply of the liver is reduced exceeding the fall in cardiac output. As a result oxygen transport to the mesenteric bed and liver is curtailed. There is a concomitant impairment of hepatic venous outflow. These hemodynamic changes may cause functional, structural and metabolic disturbances in organs whose blood supply arises from splanchnic circulation.

[Supine thoracic images with a mobile roentgen unit: comparison between the soft-ray and hard-ray technics]

To compare the influence of kilovoltage on the quality of supine chest roentgenograms obtained with a mobile x-ray unit, we examined the films of 50 patients on whom supine chest radiographs had been taken incidentally within a period of 24 hours both with high and with low-kVp technique. For evaluation of the image quality, a total of 11 criteria were compared and quantitated by 5 observers using a simple score method. The same advantages that have been attributed to the high-kVp technique on upright films were found on the corresponding supine examinations. These films showed a more balanced penetration and greater sharpness than those taken with low-kVp. The wider latitude of the high-kVp technique simplifies the exposure, and fewer repeat takes will therefore be necessary. The diagnostic gain outweights the few disadvantages, which are mostly coupled to the increase in scattered radiation. This, as well as the availability of more powerful and efficient mobile generators, should promote routine application of high-kVp technique for supine chest examinations.