Hypoxemic reperfusion of ischemic states: an alternative approach for the attenuation of oxidative stress mediated reperfusion injury

Ischemia and reperfusion (I/R) - induced injury has been described as one of the main factors that contribute to the observed morbidity and mortality in a variety of clinical entities, including myocardial infarction, ischemic stroke, cardiac arrest and trauma. An imbalance between oxygen demand and supply, within the organ beds during ischemia, results in profound tissue hypoxia. The subsequent abrupt oxygen re-entry upon reperfusion, may lead to a burst of oxidative aggression through production of reactive oxygen species by the primed cells. The predominant role of oxidative stress in the pathophysiology of I/R mediated injury, has been well established. A number of strategies that target the attenuation of the oxidative burst have been tested both in the experimental and the clinical setting. Despite these advances, I/R injury continues to be a major problem in everyday medical practice. The aim of this paper is to review the existing literature regarding an alternative approach, termed hypoxemic reperfusion, that has exhibited promising results in the attenuation of I/R injury, both in the experimental and the clinical setting. Further research to clarify its underlying mechanisms and to assess its efficacy in the clinical setting is warranted.

Nitrosative and oxidative stresses contribute to post-ischemic liver injury following severe hemorrhagic shock: the role of hypoxemic resuscitation

PURPOSE

Hemorrhagic shock and resuscitation is frequently associated with liver ischemia-reperfusion injury. The aim of the study was to investigate whether hypoxemic resuscitation attenuates liver injury.

METHODS

Anesthetized, mechanically ventilated New Zealand white rabbits were exsanguinated to a mean arterial pressure of 30 mmHg for 60 minutes. Resuscitation under normoxemia (Normox-Res group, n = 16, PaO(2) = 95-105 mmHg) or hypoxemia (Hypox-Res group, n = 15, PaO(2) = 35-40 mmHg) followed, modifying the FiO(2). Animals not subjected to shock constituted the sham group (n = 11, PaO(2) = 95-105 mmHg). Indices of the inflammatory, oxidative and nitrosative response were measured and histopathological and immunohistochemical studies of the liver were performed.

RESULTS

Normox-Res group animals exhibited increased serum alanine aminotransferase, tumor necrosis factor--alpha, interleukin (IL) -1β and IL-6 levels compared with Hypox-Res and sham groups. Reactive oxygen species generation, malondialdehyde formation and myeloperoxidase activity were all elevated in Normox-Res rabbits compared with Hypox-Res and sham groups. Similarly, endothelial NO synthase and inducible NO synthase mRNA expression was up-regulated and nitrotyrosine immunostaining increased in animals resuscitated normoxemically, indicating a more intense nitrosative stress. Hypox-Res animals demonstrated a less prominent histopathologic injury which was similar to sham animals.

CONCLUSIONS

Hypoxemic resuscitation prevents liver reperfusion injury through attenuation of the inflammatory response and oxidative and nitrosative stresses.

Hypoxemic resuscitation from hemorrhagic shock prevents lung injury and attenuates oxidative response and IL-8 overexpression

We investigated whether hypoxemic resuscitation from hemorrhagic shock prevents lung injury and explored the mechanisms involved. We subjected rabbits to hemorrhagic shock for 60 min by exsanguination to a mean arterial pressure of 40 mm Hg. By modifying the fraction of the inspired oxygen, we performed resuscitation under normoxemia (group NormoxRes, P(a)O(2)=95-105 mm Hg) or hypoxemia (group HypoxRes, P(a)O(2)=35-40 mm Hg). Animals not subjected to shock constituted the sham group (P(a)O(2)=95-105 mm Hg). We performed bronchoalveolar lavage (BAL) fluid, lung wet-to-dry weight ratio, and morphological studies. U937 monocyte-like cells were incubated with BAL fluid from each group. Cell peroxides, malondialdehyde, proteins, and cytokines in the BAL fluid were lower in sham than in shocked animals and in HypoxRes than in NormoxRes animals. The inverse was true for ascorbic acid and reduced glutathione. Lung edema, lung neutrophil infiltration, myeloperoxidase, and interleukin (IL)-8 gene expression were reduced in lungs of HypoxRes compared with NormoxRes animals. A colocalized higher expression of IL-8 and nitrotyrosine was found in lungs of NormoxRes animals compared to HypoxRes animals. The BAL fluid of NormoxRes animals compared with HypoxRes animals exerted a greater stimulation of U937 monocyte-like cells for proinflammatory cytokine release, particularly for IL-8. In the presence of p38-MAPK and Syk inhibitors and monosodium urate crystals, IL-8 release was reduced. We conclude that hypoxemic resuscitation from hemorrhagic shock ameliorates lung injury and reduces oxygen radical generation and lung IL-8 expression.

Oral atovaquone for the treatment of severe Pneumocystis jirovecii pneumonia in a patient with glucose-6-phosphate dehydrogenase deficiency

We present a case of severe Pneumocystis jirovecii pneumonia and coexisting cytomegalovirus infection in a glucose-6-phosphate dehydrogenase (G6PD) enzyme deficient woman with anaplastic astrocytoma on temozolomide and corticosteroid therapy. She was successfully treated with oral atovaquone and ganciclovir. Atovaquone represents a safe alternative in severe Pneumocystis infection when trimethoprim-sulfamethoxazole (co-trimoxazole) is contraindicated.

High concentrations of reactive oxygen species in the BAL fluid are correlated with lung injury in rabbits after hemorrhagic shock and resuscitation

Increased levels of cytokines or reactive oxygen species (ROS) in the bronchoalveolar lavage (BAL) fluid are associated with acute lung injury after ischemia/reperfusion. We investigated the correlation of these markers with the degree of lung injury in a rabbit model of hemorrhagic shock. Rabbits, maintained by mechanical ventilation, were left untreated (control) or subjected to hemorrhagic shock by withdrawing blood (n = 12 for each group). Shock animals were re-infused their shed blood for resuscitation. At the end of the experiment, BAL fluid was recovered, in which parameters of oxidative stress and cytokines were measured. Macrophages and malondialdehyde levels were increased (p = 0.043 and p = 0.003, respectively), and total antioxidant capacity (TAC) was decreased in the shock animals compared with control (p = 0.009). Production of ROS was significantly enhanced in shock animals compared with controls (p < 0.001). BAL fluid levels of tumor necrosis factor-alpha, interleukin (IL)-1beta and IL-6 were higher in shock rabbits by more than twofold (p < 0.001 for each). Shock animals also showed higher histopathological scores that represent severe tissue damage than controls (p = 0.022). Numbers of macrophages and levels of ROS and TAC were correlated with the degree of lung injury (p = 0.006, p = 0.02, and p = 0.04, respectively), but not cytokines. Therefore, resuscitation from hemorrhagic shock results in acute lung injury, with enhanced pulmonary oxidative and inflammatory responses. In conclusion, ROS in the BAL fluid are good markers that predict lung injury following hemorrhagic shock and resuscitation.

Ampicillin-sulbactam: an update on the use of parenteral and oral forms in bacterial infections

Ampicillin-sulbactam has a wide range of antibacterial activity that includes Gram-positive and Gram-negative aerobic and anaerobic bacteria. However, the drug is not active against Pseudomonas aeruginosa and pathogens producing extended-spectrum beta-lactamases. The combination could be considered particularly active against Acinetobacter baumannii infections due to the intrinsic activity of sulbactam. The drug is indicated as empirical therapy for a broad range of community acquired infections supervened in adults or children and is effective in either parenteral (ampicillin-sulbactam) or oral (as a mutual prodrug sultamicillin) form. In clinical trials, sultamicillin has proved clinically and bacteriologically effective in adults and children against a variety of frequently encountered infections, including mild upper and lower respiratory tract infections, urinary tract infections, diabetic foot and skin and soft tissue infections. Furthermore, adverse effects rarely occur with the diarrhoea to represent the most commonly reported. The parenteral ampicillin-sulbactam is indicated for community infections of mild-to-moderate severity acquired infections such as intra-abdominal or gynecological. Moreover, it seems to represent the alternative of choice for the treatment of A. baumannii infections for carbapenem-resistant strains in the nosocomial setting. Thus, ampicillin-sulbactam remains a valuable agent in the physician's armamentarium in the management of adult and pediatric infections.

Reasons of PEG failure to eliminate gastroesophageal reflux in mechanically ventilated patients

AIM: To investigate factors predicting failure of percutaneous endoscopic gastrostomy (PEG) to eliminate gastroesophageal reflux (GER).

METHODS: Twenty-nine consecutive mechanically ventilated patients were investigated. Patients were evaluated for GER by pH-metry pre-PEG and on the 7th post-PEG day. Endoscopic and histologic evidence of reflux esophagitis was also carried out. A beneficial response to PEG was considered when pH-metry on the 7th post-PEG day showed that GER was below 4%.

RESULTS: Seventeen patients responded (RESP group) and 12 did not respond (N-RESP) to PEG. The mean age, sex, weight and APACHE II score were similar in both groups. GER (%) values were similar in both groups at baseline, but were significantly reduced in the RESP group compared with the N-RESP group on the 7th post-PEG day [2.5 (0.6-3.8) vs 8.1 (7.4-9.2, P < 0.001)]. Reflux esophagitis and the gastroesophageal flap valve (GEFV) grading differed significantly between the two groups (P = 0.031 and P = 0.020, respectively). Histology revealed no significant differences between the two groups.

CONCLUSION: Endoscopic grading of GEFV and the presence of severe reflux esophagitis are predisposing factors for failure of PEG to reduce GER in mechanically ventilated patients.

Monocytes as a site of production of soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) in the septic host

The role of blood monocytes in the secretion of soluble triggering receptor expressed on myeloiod cells (sTREM-1) was studied in 90 patients with septic syndrome due to ventilator-associated pneumonia. Blood monocytes were isolated on 7 consecutive d after initiation of symptoms. Monocytes were incubated in the absence or presence of LPS and concentrations of sTREM-1 and TNFalpha in cell supernatants and serum were estimated by an enzyme-immunoassay. sTREM-1 and TNFalpha were consistently present at detectable levels in the cell supernatants. LPS induced increased levels of TNFalpha but not of sTREM-1. Supernatants recovered from monocytes on d 1 showed levels of sTREM-1 higher than those recovered on any of the following 6 d (p<0.05); these levels were higher in non-survivors than in survivors. Supernatants recovered from monocytes on d 1 of patients with severe sepsis had elevated concentrations of sTREM-1 compared to patients with septic shock and similar to patients with sepsis. A negative correlation was found between levels of sTREM-1 in the cell supernatants and the percentage of apoptotic monocytes. In essence, the above results suggest that monocytes contribute to the production of sTREM-1 in the event of septic syndrome.

Hypoxemic resuscitation after hemorrhagic shock is accompanied by reduced serum levels of angiopoietin-2

BACKGROUND

To investigate whether angiopoietin-2 (Ang2) and vascular endothelial growth factor (VEGF) are implicated in the hypoxemic resuscitation from hemorrhagic shock.

METHODS

Twenty rabbits were subjected to hemorrhagic shock after blood exsanguination; resuscitation was performed by infusion of the shed blood in ten rabbits under normoxemic conditions (NormoxRes) and in 10 under hypoxemic conditions (HypoxRes); four rabbits were subjected to sham operation. Serum was drawn at serial time intervals; serum was applied for stimulation of U937 monocytes.

RESULTS

Serum concentrations of Ang2 were higher in the NormoxRes group compared to the HypoxRes group at 90 min (p: 0.049) and at 120 min (p: 0.028). Serum concentrations of VEGF did not differ between groups. Concentrations of VEGF in the supernatants of U937 stimulated with sera of all groups were below detection limit. The wet to dry lung ratio of the HypoxRes group was significantly lower than the NormoxRes group (p<0.0001).

CONCLUSIONS

Hypoxemic resuscitation from hemorrhagic shock is a process accompanied by reduced serum levels of Ang2. These findings add significantly to our understanding of that experimental treatment strategy of resuscitation.

The level of hypotension during hemorrhagic shock is a major determinant of the post-resuscitation systemic inflammatory response: an experimental study

Background

To evaluate whether the level of hypotension during hemorrhagic shock may influence the oxidative and inflammatory responses developed during post-ischemic resuscitation.

Methods

Fifteen rabbits were equally allocated into three groups: sham-operated (group sham); bled within 30 minutes to mean arterial pressure (MAP) of 40 mmHg (group shock-40); bled within 30 minutes to MAP of 30 mmHg (group shock-30). Shock was maintained for 60 min. Resuscitation was performed by reinfusing shed blood with two volumes of Ringer's lactate and blood was sampled for estimation of serum levels aminotransferases, creatinine, TNF-α, IL-1β, IL-6, malondialdehyde (MDA) and total antioxidant status (TAS) and for the determination of oxidative burst of polymorhonuclears (PMNs) and mononuclear cells (MCs).

Results

Serum AST of group shock-30 was higher than that of group shock-40 at 60 and 120 minutes after start of resuscitation; serum creatinine of group shock-30 was higher than group shock-40 at 120 minutes. Measured cytokines, MDA and cellular oxidative burst of groups, shock-40 and shock-30 were higher than group sham within the first 60 minutes after start of resuscitation. Serum concentrations of IL-1β, IL-6 and TNF-α of group shock-30 were higher than group shock-40 at 120 minutes (p < 0.05). No differences were found between two groups regarding serum MDA and TAS and oxidative burst on PMNs and MCs but both groups were different to group sham.

Conclusion

The level of hypotension is a major determinant of the severity of hepatic and renal dysfunction and of the inflammatory response arising during post-ischemic hemorrhagic shock resuscitation. These findings deserve further evaluation in the clinical setting.

Efficacy and safety of high-dose ampicillin/sulbactam vs. colistin as monotherapy for the treatment of multidrug resistant Acinetobacter baumannii ventilator-associated pneumonia

OBJECTIVE

To compare the safety and efficacy of ampicillin/sulbactam (Amp/Sulb) and colistin (COL) in the treatment of multidrug resistant Acinetobacter baumannii ventilator-associated pneumonia (VAP).

METHODS

A prospective cohort study in adult critically ill patients with VAP. Patients were randomly assigned to receive Amp/Sulb (9 g every 8h) or COL (3 MIU every 8h) intravenously. Dosage was adjusted according to creatinine clearance.

RESULTS

A total of 28 patients were enrolled (15 COL, 13 Amp/Sulb). Resolution of symptoms and signs occurred in 60% (9/15) of the COL group and 61.5% (9/13) of the Amp/Sulb group, improvement in 13.3% (2/15) vs. 15.3% (1/13) and failure in 26.6% (4/15) vs. 23% (3/13), respectively. The difference was not statistically significant. Bacteriologic success was achieved in 66.6% (10/15) vs. 61.5% (8/13) in the COL and Amp/Sulb groups, respectively (p<0.2). Mortality rates (14 days and 28 days) were 15.3% and 30% for the Amp/Sulb and 20% and 33% for the COL group, respectively. Adverse events were 39.6% (including 33% nephrotoxicity) for the COL group and 30.7% (15.3% nephrotoxicity) for the Amp/Sulb group (p=NS).

CONCLUSION

Colistin and high-dose ampicillin/sulbactam were comparably safe and effective treatments for critically ill patients with MDR A. baumannii VAP.

Immunomodulatory effect of three-day continuous administration of clarithromycin for experimental sepsis due to multidrug-resistant Pseudomonas aeruginosa

Based on former animal studies showing the effect of clarithromycin in experimental sepsis by multidrug-resistant Pseudomonas aeruginosa following administration of single doses, the significance of its administration for three consecutive days was evaluated. Acute pyelonephritis was induced in 20 rabbits after inoculation of the test isolate in the renal pelvis. Therapy was administered upon signs of sepsis in group B; A served as control. Survival was recorded; monocytes were isolated for determination of ex vivo TNFalpha secretion. Quantitative cultures of organs were performed after death. Mean survival of groups A and B was 2.65 and 7.95 days respectively. At 24 hours, serum malondialdehyde of group B, which is an index of the oxidant status in serum, was lower than A. Ex vivo release of TNFalpha by the isolated monocytes of group B was lower than A at 3.5 and 48 hours. Tissue bacterial load was similar in two groups after animal death. It is concluded that clarithromycin possessed considerable immunomodulatory effects restraining release of TNFalpha from blood monocytes.

Acute renal dysfunction in liver diseases

Renal dysfunction is common in liver diseases, either as part of multiorgan involvement in acute illness or secondary to advanced liver disease. The presence of renal impairment in both groups is a poor prognostic indicator. Renal failure is often multifactorial and can present as pre-renal or intrinsic renal dysfunction. Obstructive or post renal dysfunction only rarely complicates liver disease. Hepatorenal syndrome (HRS) is a unique form of renal failure associated with advanced liver disease or cirrhosis, and is characterized by functional renal impairment without significant changes in renal histology. Irrespective of the type of renal failure, renal hypoperfusion is the central pathogenetic mechanism, due either to reduced perfusion pressure or increased renal vascular resistance. Volume expansion, avoidance of precipitating factors and treatment of underlying liver disease constitute the mainstay of therapy to prevent and reverse renal impairment. Splanchnic vasoconstrictor agents, such as terlipressin, along with volume expansion, and early placement of transjugular intrahepatic portosystemic shunt (TIPS) may be effective in improving renal function in HRS. Continuous renal replacement therapy (CRRT) and molecular absorbent recirculating system (MARS) in selected patients may be life saving while awaiting liver transplantation.

Grouping of patients with common variable immunodeficiency based on immunoglobulin biosynthesis: comparison with a classification system on CD4-naïve cells

The present study compared two different systems of classification of patients with common variable immunodeficiency (CVID); one based on in vitro immunoglobulin biosynthesis; and another on CD4-naïve cell counts. Peripheral blood mononuclear cells (PBMCs) were isolated from 35 patients with CVID and 20 healthy controls. They were stimulated for the secretion of IgM and IgG after stimulation with Staphylococcus aureus Cowan I (SAC) upon supplementation of interleukin-2 (IL-2) or with pokeweed mitogen. T cell subsets were estimated by flow cytometry. By the first system, patients were classified into group A (n=18) with secretion of neither IgG nor IgM; into group B (n=12) with detectable IgM but no IgG secretion; and into group C (n=5) with IgM and IgG secretion similar to controls. By the second system, patients were classified into group I (n=12) with less than 109 CD4-naïve cells/mul; into group II (n=12) with CD4-naïve cells within 109-225microl(-1); and into group III (n=11) with more than 225 CD4-naïve cells/mul. All groups I-III were defective for in vitro release of IgG and IgM. The likelihood ratio for splenomegaly in patients with <225 CD4-naïve cells/mul was 5.08 (p: 0.024). CD4-naïve cell counts of patients were positively correlated to serum levels of IgG and IgA of patients. The presented results revealed that the former system described adequately the function of B cells and the latter the clinical status of the patient. Our proposal is that both should be used for the characterization of patients with CVID.

Stimulation of monocytes is a pathway involved in systemic inflammatory response following haemorrhagic shock resuscitation: the effect of hypoxaemic resuscitation

The present study was designed to investigate whether serum of animals subjected to hypoxaemic resuscitation from haemorrhagic shock may be a weak stimulant for monocytes or not. Twenty rabbits were subjected to haemorrhagic shock after blood exsanguination; resuscitation was performed by infusion of the shed blood in eight rabbits under normoxaemic conditions (NormoxRes) and in 12 under hypoxaemic conditions (HypoxRes); seven rabbits were subjected to sham operation. Malondialdehyde (MDA) and tumour necrosis factor (TNF)-alpha were estimated in serum at serial time intervals; the serum was applied for stimulation of U937 monocytes with or without the p38 mitogen-activated protein kinase (MAPK) inhibitor SB203580. Expression of triggering receptor expressed on myeloid cells-1 (TREM-1) on U937 was also assessed by flow cytometric analysis. Death supervened in four animals of the NormoxRes (50%) and in one animal of the HypoxRes group (8.33%, P: 0.032). Serum levels of TNF-alpha and MDA were higher in NormoxRes compared to HypoxRes animals. Expression of TREM-1 on U937 monocytes was similar after stimulation with serum sampled from both groups. Concentrations of interleukin (IL)-1beta, IL-6 and IL-8 of monocyte supernatants were higher after stimulation with serum of NormoxRes than HypoxRes rabbits. Production of cytokines after stimulation with serum was decreased significantly after addition of SB203580. It is concluded that stimulation of monocytes may contribute to the generation of the systemic inflammatory response during reperfusion after ischaemia. Lower stimulation of the p38 MAPK-mediated production of IL-1beta, IL-6 and IL-8 by monocytes may be implicated as an explanation for the benefits shown for the host when resuscitation is performed under hypoxaemic conditions.

Early apoptosis of blood monocytes is a determinant of survival in experimental sepsis by multi-drug-resistant Pseudomonas aeruginosa

Apoptosis of blood monocytes was studied in experimental sepsis by multi-drug-resistant Pseudomonas aeruginosa. Thirty-six rabbits were used, divided into the following groups: A (n = 6), sham; B (n = 6), administered anaesthetics; and C (n = 24), acute pyelonephritis induced after inoculation of the test isolate in the renal pelvis. Blood was sampled at standard time intervals for estimation of tumour necrosis factor (TNF)-alpha and isolation of monocytes. Half the monocytes were incubated and the other half was lysed for estimation of the cytoplasmic activity of caspase-3 by a kinetic chromogenic assay. No animal in groups A and B died; those in group C were divided into two subgroups, CI (n = 8) with present activity of caspase-3 of blood monocytes at 3.5 h and CII (n = 16) with absent activity. Their median survival was 2.0 and 3.5 days, respectively (P = 0.0089). Ex vivo secretion of TNF-alpha from monocytes was higher by monocytes of subgroup CII than subgroup CI at 3.5 h (P = 0.039) and of group A than CII at 48 h (P = 0.010). Median change of caspase-3 activity between 3.5 and 24 h of sampling was 56.1 and -5.8 pmol/min per 10(4) cells for subgroups CI and CII (P = 0.040), respectively. Respective changes between 3.5 and 48 h were 28 981.0 and 0 pmol/min per 10(4) cells (P = 0.036). Early induction of apoptosis in blood monocytes is of prime importance for the survival of the septic host and might be connected to changes of monocyte potential for the secretion of TNF-alpha.

Neutrophil CD64 expression and serum IL-8: Sensitive early markers of severity and outcome in sepsis

The aim of the present study was to investigate which biomarker/s reliably assess severity and mortality early in the sepsis process. In 47 critically-ill patients within the 24h of septic onset, Interleukins (IL)-8, -1beta, -6, -10, and -12p70, tumor necrosis factor-alpha (TNF-alpha), procalcitonin (PCT) and C-reactive protein (CRP) were measured in serum. Additionally, CD64 expression was measured in neutrophils. In early sepsis, neutrophil CD64 expression and IL-8 levels are the only biomarkers that increased with sepsis severity, differentiating disease stages: sepsis, severe sepsis and septic shock (p<0.001). The biomarkers that best evaluate the severity of sepsis (via APACHE II) were CD64, IL-8 and IL-6 (p<0.01), and the severity of organ failure (via SOFA) were CD64 and IL-8 (p<0.01). CD64 expression and IL-8 levels were associated with mortality within 28-days (OR=1.3, p=0.01 for CD64 and OR=1.26, p=0.024 for IL-8 by logistic regression analysis) and ROC curve analysis showed high sensitivity and specificity for predicting sepsis stages and the 28 day mortality. We conclude that there is an early increase of neutrophil CD64 expression and IL-8 levels during sepsis. Based on this single measurement it is possible to reliably assess the stage, detect the severity and predict the 28-day mortality of sepsis.

The effect of hypoxemic resuscitation of hemorrhagic shock on hemodynamic stabilization and inflammatory response: a pilot study in a rat experimental model

BACKGROUND

Resuscitation of hemorrhagic shock is associated with tissue injury. The effect of hypoxemia during resuscitation was investigated.

METHODS

Shock was induced by withdrawing blood to mean arterial pressure (MAP) 40 mm Hg and maintained for 60 minutes in 25 Wistar rats. Animals were randomly divided to receive either normoxemic (controls, FiO2 = 21%, n = 14) or hypoxemic (HypRes, FiO2 = 12%, n = 11) resuscitation by re-infusing their shed blood. Outcome was assessed through hemodynamic and inflammatory parameters. Another nine rats served to correlate different FiO2 to the corresponding PaO2.

RESULTS

At 60 minutes of resuscitation HypRes had higher MAP than control animals (p = 0.008). The respective median (range) malondialdehyde and TNF-alpha levels was 1.7 (1-2.1) versus 3.1 (2.4-4.3) micromol/L, (p = 0.02) and 0 versus 5.8 (0-5.8) pg/mL, (p = 0.025). Glutathione, endotoxin, interferon-gamma, and nitric oxide values were similar between groups. FiO2 of 12% induced only a mild hypoxemia (PaO2 approximately 80 mm Hg).

CONCLUSIONS

Even mild hypoxemia during resuscitation of shock leads to effective hemodynamic stabilization.

Induction chemotherapy followed by concurrent chemoradiation in advanced squamous cell carcinoma of the head and neck: Final results from a phase II study with docetaxel, cisplatin and 5-fluorouracil with a four-year follow-up

Encouraging results have recently been reported in patients (pts) with locally advanced unresectable squamous cell carcinoma of the head and neck (SCCHN) when induction chemotherapy (IC) is used and followed by radiotherapy (RT). The present study assessed the therapeutic response of an aggressive regimen consisting of docetaxel (TXT), cisplatin (CDDP) and 5-fluorouracil (5-Fu) as IC and concurrent with RT in pts with locally advanced (stages III and IV) SCCHN. 42 pts (35 male and 7 female) with a mean age of 58 years suffering from stages III and IV (Mo) SCCHN were included to this organ preservation phase II clinical trial. The site of the primary tumors was the anterior mouth in 9 pts, base of tongue and oropharynx in 12, middle third of the face in 8 and larynx in 13. The performance status of the pts was 0-1 according to WHO and above 80% according to Karnofsky classification. IC consisted of TXT (40 mg/m2), CDDP (40 mg/m2) and 5-Fu (350 mg/m2) every two weeks (wks) for a total of four courses and repeated, coupled with RT (66-68 cGys total dose fractionated at 200 Gy per day, 5 days a week), for up to seven wks. In total, pts received eight courses of chemotherapy (CT) at the end of RT treatment. Pts were evaluated at the end of IC, after RT and every six wks thereafter. 41 pts were eligible for evaluation after IC (one died from myocardial infarction) and 39 after completion of treatment (two died during RT). Statistical multivariate analysis was performed using SPSS (11) package. Complications from IC and RT were evaluated according to WHO criteria and included mucositis Grade (Gr) IV in 10% of the pts, Gr III in 50%, Gr II in 20%. Anemia presented in 40% of the pts with Gr II, 40% with Gr I, neutropenia 17% with Gr IV, 20% with Gr III, 30% with Gr II, thrombocytopenia 3% with Gr III, 10% with Gr I and xerostomia up to Gr II in 70% of the pts. The response rate (RR) after IC was complete response (CR) for 10 pts (24.4%), partial response (PR) for 22 (53.7%) and no response (NR) for 9 (21.9%). At the end of the treatment the RR in the intention-to-treat population were CR for 25 pts (64.1%), and PR for 14 (35.9%). Follow up ranges from 18 to 56 months (mts). 14 pts died during follow-up time. The mean survival time is 41 mts and the median 40. 2 pts with CR developed local recurrence and two distant metastases, whereas all pts with PR developed progressive disease (PD) and all but two are dead from disease. It is evident from this phase II study that TXT-CDDP-5Fu based IC followed by the same regimen coupled with RT improves local control. Pts that showed CR after IC continued to maintain disease status during RT (P-value=0.0181). In pts with SD concurrent RT did not alter dramatically disease outcome. Patients who showed complete response after both IC and RT presented a four-year survival rate of 74% compared to a 30% to partial responders (P-value=0.0001). Results are encouraging and further study of the toxicity and follow-up is needed to validate treatment effectiveness.

Short-term effect of orlistat on dietary glycotoxins in healthy women and women with polycystic ovary syndrome

Exogenous advanced glycation endproducts (AGEs, known atherogenic molecules) abundant in everyday precooked, rich in fat, overheated meals can possibly contribute to the increased risk for diabetes and cardiovascular disease in women with polycystic ovary syndrome (PCOS). The aim of the present study was to investigate the effect of a lipase inhibitor on absorbed food glycotoxins in healthy women and those with PCOS. A 2-day protocol was followed. In the first day, a meal rich in AGE was provided, which on the second day was followed by two 120-mg capsules of lipase inhibitor, orlistat. Serum AGE levels were evaluated at baseline (0 hours), and at 3 and 5 hours postmeal during the study. Thirty-six women were studied, 15 controls (mean age, 28.80 +/- 5.47 years; body mass index, 25.85 +/- 6.73 kg/m(2)) and 21 with PCOS (mean age, 25.29 +/- 5.06 years; body mass index, 30.40 +/- 7.51 kg/m(2)) (University Hospital, Athens, Greece, institutional practice). Serum AGE levels, on day 1, were significantly increased both in the control group and in the PCOS group as compared with basal values (control group, 14.1%; PCOS group, 6.0%; P < .001). The corresponding rise was significantly lower on day 2 when the same meal was combined with orlistat (control group, 4.1%; PCOS group, 2.0%; P < .01). A limitation of the study is that it is a nonplacebo, nonrandomized therapeutic trial where each subject is considered as its own control. In conclusion, this study demonstrated the beneficial effect of orlistat on the absorption of food glycotoxins.

Effect of percutaneous endoscopic gastrostomy on gastro-esophageal reflux in mechanically-ventilated patients

AIM: To investigate the effect of percutaneous endoscopic gastrostomy (PEG) on gastroesophageal reflux (GER) in mechanically-ventilated patients.

METHODS: In a prospective, randomized, controlled study 36 patients with recurrent or persistent ventilator-associated pneumonia (VAP) and GER > 6% were divided into PEG group (n = 16) or non-PEG group (n  = 20). Another 11 ventilated patients without reflux (GER < 3%) served as control group. Esophageal pH-metry was performed by the “pull through” method at baseline, 2 and 7 d after PEG. Patients were strictly followed up for semi-recumbent position and control of gastric nutrient residue.

RESULTS: A significant decrease of median (range) reflux was observed in PEG group from 7.8 (6.2 - 15.6) at baseline to 2.7 (0 - 10.4) on d 7 post-gastrostomy (P < 0.01), while the reflux increased from 9 (6.2 - 22) to 10.8 (6.3 - 36.6) (P < 0.01) in non-PEG group. A significant correlation between GER (%) and the stay of nasogastric tube was detected (r = 0.56, P < 0.01).

CONCLUSION: Gastrostomy when combined with semi-recumbent position and absence of nutrient gastric residue reduces the gastroesophageal reflux in ventilated patients.

A new method for the early diagnosis of brain edema/brain swelling. An experimental study in rabbits

The aim of the present work is to develop a non-destructive, non-invasive technique for the early diagnosis of an oncoming brain edema based on the variation of vibration characteristics of the head system (i.e. eigenfrequency spectrum and modal damping). Besides the theoretical model that supports the basic principle, the proposed technique has been verified experimentally in animal tests. The advantage of such an approach is that the relative information is available well in advance an increase of intracranial pressure is detected. The uncontrolled intracranial hypertension is associated with increased mortality or vegetative state in head trauma. Traumatic lesions located on temporal lobe render particularly impeding the transtendorial herniation. From the medical point of view, intracranial pressure (ICP) monitoring represents an effective way for early consideration of neurological decompensation in various neurosurgical conditions particularly in the head-injured setting. However, the use of ICP monitoring is not an effective way of brain edema detection, since ICP increase very often causes irreversible problems to the patient's brain. Therefore, the determination of an earlier, less invasive and more sensitive indicator of the oncoming intracranial hypertension and of the impeding neurological deterioration is of profound importance. The present work aims at experimental verification of both eigenfrequency shifting and modal damping increase of the spectral response of the head system of rabbits, wherever a mass increase in the content of cranial shell appears. The conducted analysis concludes that the eigenfrequency spectrum and its modal damping characteristics are sufficiently sensitive parameters in order to characterize mass increase in the cranial shell. Therefore the combination of both the above parameters could be used with confidence for the early diagnosis of brain edema.

Adenoid cystic carcinoma of the head and neck. Clinicopathological analysis of 23 patients and review of the literature

Adenoid cystic carcinoma (ACC) is a rare epithelial tumor with a distinct natural history characterized by an indolent but persistent growth, late onset of distant metastases and eventual death of patients. Between 1991 and 2003, 23 patients with ACC were treated in our Department. Surgery with a curative intent followed by radiotherapy (RT) was applied in 22 patients. Complete resection was achieved in 72.73% of patients. Local recurrence occurred in 26% of patients. Positive margins emerged as the only statistically significant parameter (p < 0.0001) influencing the development of local recurrence. Distant metastasis (DM) occurred in 47.8% of patients. In 54.5% of the patients developing DM, this occurred between 5 and 10 years after the initial treatment. DM was influenced by perineural invasion (p = 0.04) and was disassociated from local control of the tumor. The mean overall survival of our patients was 70.58 months and the mean disease free survival 61.85 months. Perineural invasion (p = 0.048) and DM (p = 0.001) had a statistically significant impact on final patients' outcome. The most important factor influencing survival was DM. Its late onset, irrespectively of local control, supports the hypothesis that ACC has a potential to develop DM in the very early phases of tumor growth.

Sarcomas of the head and neck. Results from the treatment of 25 patients

AIMS

Head and neck sarcomas comprise a heterogenous and biologically diverse group of rare neoplasms. In an effort to clarify some of the obscure clinical behavior of head and neck sarcomas, we present our experience and review the relevant literature.

METHODS

Retrospective analysis of patients with histologically proven head and neck sarcomas treated in a tertiary Hospital Department between 1992 and 2002.

RESULTS

During this period, 25 patients with head and neck sarcomas were registered. Follow-up ranged from 8 to 144 months. Twenty-three patients were treated with surgery as the primary modality; 14 were treated by surgery alone. Clear margins were obtained in all of them and local control was achieved in 12/13. The 2- and 5-year survival rates for the entire group were 80 and 40%, respectively. Mean overall survival time of our patients was 62 months (median 52 months).

CONCLUSIONS

Surgical treatment remains the cornerstone of therapeutic management of head and neck sarcomas.

Hypoxemic reperfusion after 120 mins of intestinal ischemia attenuates the histopathologic and inflammatory response *

OBJECTIVE

It has been suggested that reactive oxygen species play a pivotal role in the initial organ-tissue injury during reperfusion, eliciting inflammatory reaction and multiple organ failure. It was investigated if hypoxemic reperfusion attenuates tissue injury and inflammatory response.

DESIGN

Randomized animal study.

SETTING

Medical school laboratory.

SUBJECTS

Twenty-five male pigs weighing 25-28 kg.

INTERVENTIONS

Pigs were subjected to 120 mins of intestinal ischemia by clamping the superior mesenteric artery. Upon declamping, the animals were randomly assigned to receive either hypoxemic reperfusion (HR group, n = 9) reperfused with a Pao2 = 30-35 or normoxemic reperfusion (control group, n = 16) reperfused with a Pao2 = 100 mm Hg for 120 mins. Fluids without inotropes were given to combat circulatory shock during reperfusion.

MEASUREMENTS AND MAIN RESULTS

Portal blood and intestinal and lung biopsies were collected at baseline, end of ischemia, and end of reperfusion. Histopathologic changes were scored, and interleukin-1beta, qualitative Limulus amebocyte, lysate test, and Pao2/Fio2 were measured. Eight of 16 animals of the control group and seven of nine of the HR group survived (p = .22). At the end of reperfusion, the intestinal (p = .004) and lung (p = .028) pathologic scores were lower in the HR group compared with controls. The only significant difference in concentration of interleukin-1beta in the portal blood between the two animal groups occurred 120 mins after reperfusion (p = .006). The number of HR animals with a positive Limulus test was significantly smaller compared with controls at 60 (p = .041) and 120 (p = .07) mins of reperfusion. During the period of ischemia, the Pao2/Fio2 decreased similarly in the control and HR group, whereas after 120 mins of reperfusion the rate was significantly higher in the HR group.

CONCLUSIONS

Hypoxemic reperfusion represents an intervention that may attenuate the triggering of multifactorial cascade and organ tissue injury.

Myocardial ischemia in intestinal postischemic shock: the effect of hypoxemic reperfusion

OBJECTIVE

The circulatory shock following intestinal ischemia-reperfusion injury has been attributed to hypovolemia. The purpose of the current study is to clarify the pathophysiology of this type of shock and to test the hypothesis that hypoxemic compared with normoxemic reperfusion improves hemodynamics.

DESIGN

Randomized animal study.

SETTING

Medical school laboratory.

SUBJECTS

Twenty-one pigs.

INTERVENTIONS

Pigs were subjected to 120 mins of intestinal ischemia by clamping the superior mesenteric artery. Upon declamping, the animals were randomized into two groups: a group that received hypoxemic reperfusion (HR group, n = 8) with a PaO2 = 30-35 and a control group reperfused with PaO2 = 100 mm Hg (control group, n = 13).

MEASUREMENTS AND MAIN RESULTS

Measurements included mean arterial pressure, cardiac index, pulmonary artery occlusion pressure, and requirements for fluids and epinephrine. Biopsies from the terminal ileal mucosa were taken for malondialdehyde measurements at baseline, at 120 mins of ischemia, and at 30 and 60 mins of reperfusion. A piece of left ventricle was obtained after 120 mins of reperfusion for histologic studies. Five of 13 animals of the control group died in intractable shock; no animal of the HR group died (p =.11). The decrease in the mean arterial pressure during reperfusion was more pronounced in the control group (p <.008) despite the larger doses of epinephrine administered, compared with the HR group (p <.02). During reperfusion, both groups exhibited a decrease in cardiac index; this was more pronounced in the control group (p =.0007). Pulmonary artery occlusion pressure increased during reperfusion in both groups and was more pronounced in the control group (p =.04 at 60 mins). Although mixed venous blood oxygen saturation of the control animals was higher at 30 mins of reperfusion (p =.005), it declined after 60 mins and became lower than that of HR animals at the end of reperfusion (p <.02). The myocardial histopathologic injury score was higher in the control group (2.0 +/- 0.69 and 3.4 +/- 0.89 for the HR and control groups, respectively; p <.03). The concentrations of intestinal mucosa malondialdehyde were significantly higher in the control group at 60 mins of reperfusion (p <.03).

CONCLUSIONS

Acute myocardial ischemia and left heart failure significantly contribute to the circulatory shock that follows intestinal ischemia/reperfusion injury and are attenuated by hypoxemic reperfusion.

Hypoxaemic reperfusion ameliorates the histopathological changes in the pig brain after a severe global cerebral ischaemic insult

BACKGROUND AND PURPOSE

We have recently shown that hypoxaemic reperfusion, after an ischaemic brain insult, improves neurological outcome and decreases lipid peroxidation. In the present study, we investigated the effect of hypoxaemic reperfusion on brain histopathological changes.

METHODS

Sixteen pigs subjected to a 10-min global cerebral ischaemia were either hypoxaemically (PaO2 = 35 mmHg, hypoxaemic reperfusion (HR) group, n = 8) or hyperoxaemically (PaO2 > 300 mmHg, control (C) group, n = 8) reperfused. The brains were removed 24 h after reperfusion and six neuropathological abnormalities were evaluated blindly and scored semi-quantitatively (0: normal to 3: severe injury) on eight representative regions of the brain. The overall cumulative score of the abnormalities and their regional prevalence, as well as the neurological outcome, were compared between the two groups.

RESULTS

The neuronal degeneration, assessed in terms of cumulative score (P = 0.002) and regional prevalence (P = 0.025 to P = 0.041), was lower in the HR group than in the C group. Spongy degeneration attained statistically significant difference only in cerebellum (P = 0.002) and inflammation only in hippocampus (P = 0.046) but the difference in the cumulative score of these abnormalities was not statistically significant. The difference of the three neurological assessments over time was statistically significant between the two groups, i.e. after resuscitation (P = 0.001), at 8 h (P = 0.006) and at 24 h (P = 0.001) after reperfusion.

CONCLUSIONS

Hypoxaemic reperfusion during resuscitation from a severe global ischaemic cerebral insult is associated with statistically significantly fewer histopathological changes of the brain than in controls. This is associated with a superior neurological outcome.

The effect of hypoxemic reperfusion on cerebral protection after a severe global ischemic brain insult

BACKGROUND AND PURPOSE

Reactive oxygen species contribute to membrane lipid peroxidation and neuronal death and have been implicated in anoxic encephalopathy. We tested whether hypoxemic reperfusion (HR) after global cerebral ischemia would improve neurological recovery.

METHODS

Two groups of pigs (n = 11 in each group) were subjected to a model of a 10-min global cerebral and systemic ischemia to compare the effect of hypoxemic reperfusion (group HR) with the classical hyperoxemic control (group C). A third group not subjected to ischemia served as control to the control group (n = 6, group CC), but received hyperoxygenation at the respective period of reperfusion. The outcome was evaluated by means of neurological assessment and the extent of lipid peroxidation measuring the plasma malonaldehyde (MDA) together with hydroxyalkenals (HALK).

RESULTS

Animals of group HR exhibited a significantly superior neurological outcome compared with those of group C at all three consecutive assessments after reperfusion (post-resuscitation P = 0.006, at 8 h P = 0.003, and at 24 h P = 0.007). The levels of MDA and HALK are lower in the HR group than in group C (P = 0.029). Additionally, in the CC group these molecules increased significantly early at hyperoxygenation (P = 0.02). A faster lactate metabolism in the HR group was observed during reperfusion, though non-significant.

CONCLUSIONS

Hypoxemic reperfusion during resuscitation from a severe global ischemic cerebral insult improves the neurological outcome compared with classic hyperoxemic reperfusion. This is additionally confirmed by the decreased production of the molecules of lipid peroxidation. In the absence of preceding ischemia, these molecules may increase by simple over-oxygenation.

Prevention of infection in multiple trauma patients by high-dose intravenous immunoglobulins

OBJECTIVE

To investigate the activity of intravenous immunoglobulin (IVIG) as a prophylactic agent against infection in trauma victims.

DESIGN

Prospective, randomized, double-blind, placebo-controlled study.

SETTING

A 20-bed university intensive care unit.

PATIENTS

Thirty-nine trauma patients with injury severity scores (ISSs) of 16-50.

INTERVENTIONS

Penicillin was given at the time of admission and continued at least until day 4. Twenty-one patients received IVIG and 18 patients received human albumin at 1 g/kg in four divided doses (days 1, 2, 3, and 6). The two groups had similarities in age, gender, Acute Physiology and Chronic Health Evaluation II score, risk of death, and Glasgow Coma Scale score, but differing ISSs (p = .02), at the time of admission. Blood was collected on days 1, 4, and 7.

MEASUREMENTS AND MAIN RESULTS

Clinical variables related to infection were recorded. The complement components C3c, C4 and CH50, IgG, and the fractions of IgG were measured. The serum bactericidal activity (SBA) was assessed at 37 degrees C (98.6 degrees F) and 40 degrees C (104.0 degrees F) at the time of admission and during the course of IVIG administration. Controlling for ISS, IVIG-treated patients had fewer pneumonias (p = .003) and total non-catheter-related infections (p = .04). Catheter-related infections (p = .76), length of stay in the intensive care unit, antibiotic days, and infection-related mortality did not differ between the two groups. A significantly increased trend in IgG and its subclasses was shown on days 4 and 7 in the IVIG group but not in the control group (p<.000001). No important differences were noted in complement fractions. The SBA of the groups was similar on day 1, but significantly higher on days 4 and 7 (p<.000001) in the IVIG group, remaining so controlling for complement and ISS. SBA was higher at 40 degrees C (104.0 degrees F) compared with 37 degrees C (98.6 degrees F) (p<.0001) under all three conditions. In both groups, low SBA (on days 1, 4, and 7) was associated with increased risk of pneumonia (p<.01) and non-catheter-related infections (p = .06 for day 1; p<.01 for days 4 and 7).

CONCLUSIONS

Trauma patients receiving high doses of IVIG exhibit a reduction of septic complications and an improvement of SBA. Early SBA measurement may represent an index of susceptibility to infection.

Brain eigenfrequency shifting as a sensitive index of cerebral compliance in an experimental model of epidural hematoma in the rabbit: preliminary study

OBJECTIVE

To verify brain eigenfrequency shifting after the occurrence of a lesion producing mass effect into the cranial vault.

DESIGN

Experimental animal study.

SETTING

Laboratory of experimental surgery affiliated with a university critical care department.

SUBJECTS

Six adult male New Zealand white rabbits.

INTERVENTIONS

A Camino ICP monitor was placed in the parenchyma, and a 5-Fr balloon-tipped catheter and accelerometer were placed into the epidural space.

MEASUREMENTS

Before and after the introduction of successive 0.1-mL increments of autologous blood into the balloon, intracranial pressure (ICP) was recorded along with the accelerometer signal obtained during free vibration of the skull triggered by a calibrated hammer. Fast Fourier transformation of the digitized signal provided the eigenfrequency spectrum. The eigenfrequency showing the sharpest decrease after the initial 0.1-mL volume addition was considered as the best frequency, and its variation in response to subsequent 0.1-mL increments represents the brain eigenfrequency shifting.

MAIN RESULTS

Brain eigenfrequency shifting to lower values occurs for small blood volume increments (up to 0.2 mL). When volume addition becomes >0.3 mL, brain eigenfrequency shifting to higher values is exhibited. The decrease in best frequency after the initial introduction of 0.1 mL is statistically significant (p = .003), in a range of volume in which no significant intracranial pressure difference appears. The respective variation of ICP is explained using a quadratic curve. For volumes of 0 to 0.1 mL, the change in ICP is not statistically significant (p = .08).

CONCLUSIONS

Changes of the brain's physical characteristics by mass addition in the cranial vault can be expressed by brain eigenfrequency shifting. The method seems advantageous because it reliably detects mass additions at low levels where no ICP change occurs. Additionally, it provides serial measurements, and it is less invasive than the currently used methods for intracranial compliance.

Drainage tube endoscopy: a contribution to the management of severe acute pancreatitis?

Peritoneal lavage is one of the interventional approaches that have gained some attention in the early, toxaemic phase of acute pancreatitis. Additionally some kind of drainage is necessary for suppurative collections that characterize the late phase of the disease. In both the above situations tube plugging is a common problem and it is usually associated with a relapse of the patient's septic state and newly formed collection(s) on abdominal CT. Two cases are presented, in early and in late phases respectively, in which drainage tube adoscopy (DTE) re-established tube patency and ensured drainage. DTE may represent an alternative to surgery or to CT-guided paracentesis and evacuation of newly formed intra-abdominal collections secondary to tube obstruction.

The regional production of cytokines and lactate in sepsis-related multiple organ failure

In order to explore whether an organ-specific pattern in cytokine and lactate concentrations exists in patients with multiple organ failure (MOF), we measured the cytokines interleukin-1beta (IL-1beta), IL-6, and tumor necrosis factor-alpha (TNF-alpha), and lactate in blood taken from the hepatic vein, pulmonary capillaries, and peripheral veins of 10 patients with MOF with hepatic involvement (MOF-HI), eight patients with MOF and adult respiratory distress syndrome (MOF-ARDS), and five head-injured patients (controls). Ten additional patients participated in a study of arteriovenous pulmonary concentration gradients of these substances. For statistical analysis, nonparametric tests and analysis of variance (ANOVA) were used. The regional concentrations of these substances exhibited a different pattern in the two MOF groups. In the MOF-HI group, mean +/- SD cytokines IL-1beta and IL-6 (pg/ml) were respectively 216 +/- 100 and 461 +/- 343 in the hepatic sinusoidal blood; 149 +/- 52 and 293 +/- 204 in pulmonary capillary blood; and 148 +/- 105 and 234 +/- 162 in peripheral venous blood. In the MOF-ARDS group the corresponding levels were 180 +/- 103 and 235 +/- 124; 235 +/- 94 and 280 +/- 108; and 130 +/- 77 and 194 +/- 127. The TNF-alpha levels also exhibited the same pattern. The mean +/- SD corresponding levels (mmol/L) for lactate in the MOF-HI group were 3.1 +/- 1.8, 1.5 +/- 0.3, and 1.2 +/- 0.6, and in the MOF-ARDS group were 1.1 +/- 0.9, 1.8 +/- 1.1, and 1.0 +/- 0.2, respectively. The differences in the levels of all substances between the liver and lungs in the two MOF groups were statistically significant (p < 0.003). In the study of transpulmonary gradients it was shown that the levels of cytokine and lactate were lower in arterial blood than in mixed venous blood in MOF-HI patients, whereas the opposite was true in MOF-ARDS patients. In this study, we found that in MOF, cytokines and lactate are secreted from the most severely affected organs.

Bile canaliculi are defective in hepatic involvement of organ failure and recovery of liver function is due to their secondary regeneration

OBJECTIVE

To investigate the morphological changes in the liver in patients with organ failure and hyperbilirubinemia and to correlate them to the outcome.

DESIGN

A case series prospective study.

SETTING

Intensive care units of two general hospitals.

PATIENTS

Twelve patients in organ failure with predominant hepatic involvement, aged 16 to 69 years (mean 56 years).

INTERVENTIONS

Liver biopsy was performed on all patients 3-15 days after organ failure. A second biopsy was also performed on all four surviving patients, as well as on 3 patients just before death at a mean time of 16 days (6-32) and 31 days (14-55), respectively, after the first biopsy. The samples were studied by electron microscopy and findings were assessed according to Rappaport's designation.

MEASUREMENTS AND MAIN RESULTS

In the first biopsy it was shown that in zone III there was complete degeneration of bile canaliculi and hepatocytes in contrast to zone I. The grade of histological severity for zone III is positively correlated to the bilirubin concentration (p = 0.001). In the specimens from the second biopsy, it was shown that numerous, newly formed secondary bile canaliculi per 20 consecutive hepatocytes had developed in zone III in the surviving patients, whereas there was a complete absence of such canaliculi in the patients who died (mean +/- SD: 9.6 +/- 3.2 vs 0).

CONCLUSIONS

It appears that the destruction of primary bile canaliculi is a striking anatomical defect in patients with organ failure and impaired bilirubin excretion. The restoration of liver function coincides with adequate formation of new secondary bile canaliculi in zone III, giving credence to the hypothesis that this formation is an important structural change responsible for the improvement in liver function.

Early plasmapheresis in patients with thrombotic thrombocytopenic purpura

OBJECTIVES

To investigate the relationship of thrombotic thrombocytopenic purpura to adult respiratory distress syndrome (ARDS) and study the responses of thrombotic thrombocytopenic purpura patients to early plasmapheresis.

DESIGN

Case series.

SETTING

ICU of a university hospital.

PATIENTS

Twenty-four consecutive patients with thrombotic thrombocytopenic purpura, with various periods of time (1 to 18 days) having elapsed since the onset of this condition. Patients ranged in age from 17 to 66 yrs.

INTERVENTIONS

Plasmapheresis, using intermittent flow separators, was instituted soon after the patients' ICU admission. The retinoscopic findings on admission and the relationship of Pao2 to platelet counts before and after plasmapheresis therapy were recorded. Antiplatelet agents were given to the survivors to prevent relapses.

MEASUREMENTS AND MAIN RESULTS

Eighteen patients survived and six died. Plasmapheresis was administered for a range of 1 to 5 days (mean 3) and 3 to 18 days (mean 9.8) in survivors and nonsurvivors, respectively (p less than .001). Four patients with confluent fundus hemorrhages died and seven without these fundoscopic findings had easily controlled disease. Increases in Pao2 paralleled increases in platelet counts after plasmapheresis (p less than .001) in this small series of patients. Three of 18 discharged survivors relapsed over a period of 3 to 56 months of follow-up.

CONCLUSIONS

Early introduction of plasmapheresis in thrombotic thrombocytopenic purpura seems to increase the survival rate and to halt the development of ARDS. Fundus findings may be a prognostic factor in thrombotic thrombocytopenic purpura. The antiplatelet agents seem to be efficacious in the prevention of relapses.

Pseudomembranous colitis. Treatment by metronidazole

Nine cases of pseudomembranous colitis (PMC) were observed during a 20-month period. All patients had received, or were taking, antibiotics, in five cases lincomycin. The clinical syndrome of PMC occurred in two patients after a major gastrointestinal operation, in two after fracture of the neck of the femur, and in the remaining five, after administration of antibiotics for inflammatory diseases. The clinical syndrome was characterized by an acute onset of profuse diarrhea, pyrexia, abdominal pain, dehydration, and in four patients confusion or hypotension. The diagnosis was made on the basis of rectosigmoidoscopy and histology. No attempt was made to isolate Cl. difficile or to identify neutralizable fecal toxin. All patients received metronidazole at a dose of 1.5 gr. daily with a good response. Eight patients recovered fully. Only one died.