A semi-automated vascular access system for preclinical models

Murine models are used extensively in biological and translational research. For many of these studies it is necessary to access the vasculature for the injection of biologically active agents. Among the possible methods for accessing the mouse vasculature, tail vein injections are a routine but critical step for many experimental protocols. To perform successful tail vein injections, a high skill set and experience is required, leaving most scientists ill-suited to perform this task. This can lead to a high variability between injections, which can impact experimental results. To allow more scientists to perform tail vein injections and to decrease the variability between injections, a vascular access system (VAS) that semi-automatically inserts a needle into the tail vein of a mouse was developed. The VAS uses near infrared light, image processing techniques, computer controlled motors, and a pressure feedback system to insert the needle and to validate its proper placement within the vein. The VAS was tested by injecting a commonly used radiolabeled probe (FDG) into the tail veins of five mice. These mice were then imaged using micro-positron emission tomography to measure the percentage of the injected probe remaining in the tail. These studies showed that, on average, the VAS leaves 3.4% of the injected probe in the tail. With these preliminary results, the VAS system demonstrates the potential for improving the accuracy of tail vein injections in mice.

Risk factors for pneumothorax and bleeding after CT-guided percutaneous coaxial cutting needle biopsy of lung lesions

PURPOSE

To evaluate risk factors for pneumothorax and bleeding after computed tomography (CT)-guided percutaneous coaxial cutting needle biopsy of lung lesions.

MATERIALS AND METHODS

This study involved 117 consecutive patients with 117 intrapulmonary lesions. Statistical analysis of factors related to patient characteristics, lung lesions, and biopsy technique was performed to determine possible contribution to the occurrence of pneumothorax and bleeding. Interactions between related factors were considered to prevent colinearity.

RESULTS

Pneumothorax occurred in 12% (14 of 117) of patients. Needle aspiration of two moderate asymptomatic pneumothoraces were performed; there was no chest tube insertion. Lesion depth (P =.0097), measured from the pleural puncture site to the edge of the intrapulmonary lesion along the needle path, was the single significant predictor of pneumothorax. The highest risk of pneumothorax occurred in subpleural lesions 2 cm or shorter in depth (this represented 33% of lung lesions but caused 71% of all pneumothoraces; OR = 7.1; 95% CI, 1.3-50.8). Bleeding presented as lung parenchyma hemorrhage and hemoptysis in 30 patients (26%). Hemoptysis occurred in four patients (3%). Univariate analysis identified lesion depth (P <.0001), lesion size (P <.015), and pathology type (P =.007) as risk factors for bleeding. Multivariate logistic regression analysis identified lesion depth as the most important risk factor, with the highest bleeding risk for lesions more than 2 cm deep (14% of lesions caused 46% of all bleeding; OR = 17.3; 95% CI, 3.3-121.4).

CONCLUSIONS

In CT-guided coaxial cutting needle biopsy, lesion depth is the single predictor for risk of pneumothorax, which occurs at the highest rate in subpleural lesions. Increased risk of bleeding occurs in lesions deeper than 2 cm.

Effects of inverse ratio ventilation versus positive end-expiratory pressure on gas exchange and gastric intramucosal PCO(2) and pH under constant mean airway pressure in acute respiratory distress syndrome

BACKGROUND

In patients with acute respiratory distress syndrome, whether inverse ratio ventilation differs from high positive end-expiratory pressure (PEEP) for gas exchange under a similar mean airway pressure has not been adequately examined. The authors used arterial oxygenation, gastric intramucosal partial pressure of carbon dioxide (PiCO(2)), and pH (pHi) to assess whether pressure-controlled inverse ratio ventilation (PC-IRV) offers more benefits than pressure-controlled ventilation (PCV) with PEEP.

METHODS

Seventeen acute respiratory distress syndrome patients were enrolled and underwent mechanical ventilation with a PCV inspiratory-to-expiratory ratio of 1:2, followed by PC-IRV 1:1 initially. Then, they were randomly assigned to receive PC-IRV 2:1, then 4:1 or 4:1, and then 2:1, alternately. The baseline setting of PCV 1:2 was repeated between the settings of PC-IRV 2:1 and 4:1. Mean airway pressure and tidal volume were kept constant by adjusting the levels of peak inspiratory pressure and applied PEEP. In each ventilatory mode, hemodynamics, pulmonary mechanics, arterial and mixed venous blood gas analysis, PiCO(2), and pHi were measured after a 1-h period of stabilization.

RESULTS

With a constant mean airway pressure, PC-IRV 2:1 and 4:1 decreased arterial and mixed venous oxygenation as compared with baseline PCV 1:2. Neither the global oxygenation indices with oxygen delivery and uptake nor PiCO(2) and pHi were improved by PC-IRV. During PC-IRV, applied PEEP was lower, and auto-PEEP was higher.

CONCLUSION

When substituting inverse ratio ventilation for applied PEEP to keep mean airway pressure constant, PC-IRV does not contribute more to better gas exchange and gastric intramucosal PiCO(2) and pHi than does PCV 1:2 for acute respiratory distress syndrome patients, regardless of the inspiratory-to-expiratory ratios.

Klebsiella pneumoniae bacteremia: community-acquired vs. nosocomial infections

BACKGROUND

This study attempted to determine the clinical manifestations and influential factors affecting the prognosis of patients with community-acquired and nosocomial bacteremia of Klebsiella pneumoniae (K. pneumoniae).

METHODS

We retrospectively reviewed the medical records of 211 patients who had a clinically significant episode of K. pneumoniae bacteremia from January 1997 until December 1999.

RESULTS

Most reports describe K. pneumoniae bacteremia as typically nosocomial, but in our study approximately 3 of 4 episodes were community-acquired. Without including "unknown origin", the most common infectious site for both community-acquired and nosocomial bacteremia was the hepatobiliary tract. The overall mortality for all 211 patients with K. pneumoniae bacteremia was 25.1%. Significantly higher mortality rates occurred in patients who were elderly (> 65 years), had a nosocomial infection, for whom the respiratory tract was the portal of entry, and ultimately fatal conditions or acute complications were due to shock or renal insufficiency.

CONCLUSIONS

Patients with community-acquired and nosocomial bacteremia had different types of underlying diseases. Isolates from nosocomial infections were significantly more frequently resistant to aminoglycosides, antipseudomonal penicillin, and all three generations of cephalosporins. In this regard, an aggressive empirical therapeutic approach to infections of K. pneumoniae is suggested.

Gastric intramucosal PCO2 and pH variability in ventilated critically ill patients

OBJECTIVE

Gastric intramucosal PCO2 (PiCO2) and pH (pHi) are currently used as indices of the adequacy of splanchnic perfusion and as end points to guide therapeutic intervention. However, little is known about their spontaneous variability over time. The present study was designed to define the magnitude of spontaneous variability of PiCO2 and pHi in sedated medical intensive care unit (ICU) patients using an automated recirculating air tonometer and to test whether high-level positive end-expiratory pressure (PEEP) or inverse inspiratory/expiratory (I:E) ratio ventilation resulted in a greater variability than low PEEP with conventional I:E ratio ventilation.

DESIGN

Prospective study.

SETTING

Medical ICU in a tertiary medical center.

PATIENTS

Twenty-three acute respiratory failure patients.

INTERVENTIONS

After being sedated, patients were randomized to undergo pressure control ventilation at the following three settings: A, high PEEP (15 cm H2O) with conventional I:E ratio (1:2), and B, low PEEP (5 cm H2O) with inverse I:E ratio (2:1) alternately, and then C, low PEEP (5 cm H2O) with conventional I:E ratio (1:2). Each ventilation setting period lasted 1 hr.

MEASUREMENTS AND MAIN RESULTS

The PiCO2 and pHi were measured at baseline (time 0), and at 15, 30, 45, and 60 mins thereafter. The corresponding coefficients of variation (CVs) of PiCO2 for overall pooled group and settings A, B, and C were 4.0%, 4.4%, 3.4%, and 4.2%, respectively. The corresponding CVs of pHi for overall pooled group and settings A, B, and C were 0.36%, 0.37%, 0.33%, and 0.4%, respectively. Analysis of variance showed no significant difference in the CVs of PiCO2 or pHi between the three settings. The 95% confidence interval is approximately +/-8% variability for PiCO2 and +/-0.7% variability for pHi.

CONCLUSIONS

In critically ill medical ICU patients with stable hemodynamics, the spontaneous variability of PiCO2 or pHi are not substantial. High PEEP (15 cm H2O) and inverse ratio ventilation (2:1), which does not change the cardiac output or hemodynamics, does not contribute to increased spontaneous variability in PiCO2 or pHi.

Phase II study of regimen of gemcitabine and cisplatin in advanced non-small cell lung cancer

BACKGROUND

Cisplatin-based chemotherapy is the standard treatment for advanced non-small cell lung cancer (NSCLC). Many novel drugs, including gemcitabine, navelbine, paclitaxel and docetaxel have been used in combination with cisplatin. Of these drugs, gemcitabine is reported to have a high response rate and acceptable toxicity. The aim of this study was to evaluate the efficacy and safety of the combination of gemcitabine and cisplatin.

METHODS

Thirty-two patients with NSCLC, who met the selection criteria from June 1998 to January 1999, were enrolled. All of them were confirmed by histology and were in an advanced stage, i.e. stage IIIB with pleural effusion or stage IV. Cisplatin at a dose of 80 mg/m2 was given monthly on day 15, in combination with gemcitabine at a dose of 1000 mg/m2 administered on days 1, 8 and 15 of the 28-day cycle.

RESULTS

Of the 32 assessable patients, two showed complete remission and 11 achieved partial remission. The overall response was 40.6% (95% CI, 24.8-56.4%). The median time to disease progression was 7.2 months (95% CI, 4.87-9.53 months). The major hematological toxicity was neutropenia. Seven patients (22.9%) developed grade 3 and 4 neutropenia, but none developed febrile neutropenia. One patient (3.1%) had grade 3 thrombocytopenia. One patient (3.1%) developed grade 3 anemia. Nausea and vomiting were seen in 12 patients (37.5%).

CONCLUSIONS

The regimen of combined gemcitabine with cisplatin is safe and effective. With this combination, a lower dose of cisplatin seems to have an efficacy similar to that in previous reports.

Hyperkalemic cardiac arrest successfully reversed by hemodialysis during cardiopulmonary resuscitation: case report

Severe hyperkalemia is a potential life-threatening cardiac emergency especially in the patients who suffer from a defective renal capacity to excrete potassium such as the dialysis patient. Various conventional therapies including intravenous sodium bicarbonate, insulin with glucose and several beta-2 agonists are commonly employed as transient measures to enhance shift of potassium from the extracellular to the intracellular compartment. If the potassium load is massive and situation is critical, emergency hemodialysis may be useful. During cardiopulmonary resuscitation, the external cardiac compression can support adequate blood flow for hemodialysis. We report a case of a 68-year-old woman who developed sudden cardiac arrest secondary to hyperkalemia with renal insufficiency. Despite 100 minutes of cardiopulmonary resuscitation and conventional treatment for hyperkalemia, the cardiac arrest still persisted. Hemodialysis was then initiated during cardiopulmonary resuscitation and the patient restored spontaneous heart beat 20 minutes later. There was no neurologic sequela after her recovery. Hemodialysis should be considered early in the course of cardiopulmonary resuscitation in severe hyperkalemia induced cardiac arrest if conventional therapies were judged to be ineffective.

Fatal and non-fatal chromobacterial septicemia: report of two cases

Chromobacterium violaceum is frequently found in soil and water in tropical and subtropical regions. The organism rarely causes infection in humans, but is associated with a high mortality rate when it occurs. Septicemia associated with abscess in multiple organs such as the liver, skin, lungs, spleen, lymph nodes, and brain has been reported. We report on 2 patients with systemic infections with Chromobacterium violaceum. One presented with a fulminant course with multiple organ involvement and died 78 days later. The other presented with a milder course and survived after antibiotic therapy. In conclusion, infection with Chromobacterium violaceum is rare but its course is usually fulminant with high mortality especially in patients with sepsis and multiple organ involvement. We hope this report will provide additional information to physicians in the treatment of this disease.

Spontaneous variability of cardiac output in ventilated critically ill patients

OBJECTIVE

To define the magnitude of spontaneous cardiac output variability over time in sedated medical intensive care unit patients attached to a continuous cardiac output monitor, and to determine whether high level positive end-expiratory pressure or inverse inspiratory-to-expiratory (I:E) ratio ventilation resulted in greater variability over time than low positive end-expiratory pressure with conventional I:E ratio ventilation.

DESIGN

Prospective study.

SETTING

Medical intensive care unit in a tertiary medical center.

PATIENTS

A total of 22 hemodynamically stable acute respiratory failure patients with a pulmonary artery catheter inserted for hemodynamic monitoring

INTERVENTIONS

After being sedated, patients were randomized ultimately to receive pressure control ventilation first at setting A (high positive end-expiratory pressure [15 cm H2O] with conventional I:E ratio [1:2]) and then at setting B (low positive end-expiratory pressure [5 cm H2O] with inverse I:E ratio [2:1]), or vice versa, and then at setting C (low positive end-expiratory pressure [5 cm H2O] with conventional I:E ratio [1:2]). Each ventilation setting period lasted 1 hr.

MEASUREMENTS AND MAIN RESULTS

Cardiac output (CO) was measured continuously. The continuous CO value displayed was updated every 30-60 secs. The updated value reflected an average of the previous 3-6 mins. The coefficient of variation (CV) of CO for each setting in each patient was calculated to represent the spontaneous variability. The mean CO+/-SD and CV of each setting was 5.7+/-1.8 L/min and 4.4% for setting A, 5.6+/-1.5 L/min and 4.6% for setting B, and 5.9+/-1.7 L/min and 4.8% for setting C. Analysis of variance revealed no significant differences between the CVs of the three settings. The 95% confidence interval for the COs for each setting was approximately the mean CO+/-0.1 x mean CO measured.

CONCLUSIONS

In critically ill sedated medical intensive care unit patients with stable hemodynamics, the spontaneous variability of cardiac output over time was not significant. High positive end-expiratory pressure (15 cm H2O) and inverse ratio ventilation (2:1) did not contribute to increased spontaneous variability of cardiac output.

Carbofuran-induced delayed neuropathy

BACKGROUND

Although carbamates have been widely used in the world for many years, carbamate-induced delayed neuropathy is rare. We report what appears to be delayed neuropathy caused by poisoning with carbofuran, a cholinesterase-inhibiting carbamate, although the certainty of diagnosis is somewhat limited by the lack of a sural nerve biopsy and spinal fluid examination.

CASE REPORT

A 23-year-old man attempted suicide by ingesting 100 mL of carbofuran (2,3-dihydro-2,2-dimethyl-7-benzofuranyl methylcarbamate). After recovering from acute cholinergic toxicity, he had notable paresthesia in his lower limbs and difficulty walking. Electrophysiologic findings revealed sensorimotor neuropathy. Recovery began at 1 week and continued for 4 months. A similar delayed neuropathy has been described with carbamate, 1-naphthyl N-methylcarbamate, and m-tolyl methylcarbamate, but not with carbofuran insecticides.

Increased absolute number but not proportion of gamma/delta T-lymphocytes in the bronchoalveolar lavage fluid of patients with active pulmonary tuberculosis

SETTING

The proportions and absolute cell count of gamma/delta T-lymphocytes in the peripheral blood of patients with pulmonary tuberculosis (PTB) remains controversial. Since PTB is an infections airway disease, bronchoalveolar T-lymphocytes should be a better indicator of local immune T-cell reaction after TB infection than peripheral blood T-lymphocytes.

OBJECTIVE

To quantitate the absolute cell count and proportions of gamma/delta T-lymphocytes in the bronchoalveolar lavage fluid (BALF) of patients with active PTB.

DESIGN

Bronchoalveolar lavage (BAL) and analysis of lymphocytes in the BALF was performed in 25 patients with active PTB and 16 normal controls. All of the patients were negative for HIV infection and none was immunocompromised. BALF and blood were prepared for cell differential count and flow cytometry analysis using monoclonal antibodies CD3, CD4, CD8, CD25, HLA-DR and gamma/delta as well as alpha/beta T-lymphocyte receptors.

RESULTS

The number of cells per volume of recovered BALF was significantly higher in the patients with active PTB than in normal controls. BALF from active PTB patients also showed increased percentage of lymphocytes and neutrophils. The absolute number of total lymphocytes, CD3+ lymphocytes and CD3+ gamma/delta T-lymphocytes were significantly higher in the BALF, but not in the blood, of patients with TB, however, the proportions of CD3+ gamma/delta T-lymphocytes in BALF of patients with TB was comparable to that of normal controls. gamma/delta T-lymphocytes in the BALF rarely expressed CD4, CD25, and HLA-DR in both groups.

CONCLUSION

These results suggest that gamma/delta T-lymphocytes are not the major subpopulation of CD3+ lymphocytes in the BALF that react to mycobacterial infection in the patients with clinically established active TB.

Increased TNF-alpha, IL-1 beta and IL-6 levels in the bronchoalveolar lavage fluid with the upregulation of their mRNA in macrophages lavaged from patients with active pulmonary tuberculosis

SETTING

We hypothesized that patients with active pulmonary tuberculosis (TB) have tubercular pneumonitis and that alveolar macrophages at these sites release proinflammatory cytokines, resulting in high levels of cytokines in alveolar epithelial lining fluid.

OBJECTIVE

To measure cytokine levels in bronchoalveolar lavage fluid (BALF) and to confirm the source of any cytokines by examination of alveolar macrophage cytokine mRNA.

DESIGN

Seventeen active pulmonary TB patients and 15 healthy controls were prospectively studied. Bronchoalveolar lavage (BAL) was performed, proinflammatory cytokine levels were determined and alveolar macrophages isolated from BALF were prepared for RNA extraction and Northern blot analysis.

RESULTS

Compared with healthy controls, TNF-alpha, IL-1 beta and IL-6 in BALF were all significantly higher in patients with active pulmonary TB, 298.7 +/- 85.9 vs. 8.9 +/- 2.7 (P = 0.0001); 164.4 +/- 67.5 vs. 8.9 +/- 2.7 (P = 0.003); 969.2 +/- 214.2 vs. 86.4 +/- 17.0 (mean +/- SE pg/ml) (P = 0.0001), respectively. Only TNF-alpha and IL-6 levels were significantly higher in sera of active pulmonary TB patients, 92.3 +/- 28.7 vs. 3.5 +/- 1.2; 15.2 +/- 5.4 vs. 2.1 +/- 2.1, respectively. Northern blot analysis revealed increased gene expression of these alveolar macrophage cytokines in patients with active pulmonary TB compared healthy controls.

CONCLUSION

Significantly higher levels of TNF-alpha, IL-1 beta and IL-6 were found in BALF from patients with active pulmonary TB, and were released by alveolar macrophages in the TB lesions.

Imbalances between tumor necrosis factor-alpha and its soluble receptor forms, and interleukin-1beta and interleukin-1 receptor antagonist in BAL fluid of cavitary pulmonary tuberculosis

OBJECTIVES

We investigated the possibility that the large pulmonary cavity in tuberculosis (TB) lesions might result from imbalances between tumor necrosis factor-alpha (TNF-alpha) and soluble TNF-alpha receptor forms (sTNF-RI and sTNF-RII), and interleukin-beta (IL-1beta) and IL-1 receptor antagonist (IL-1RA) in sites of local inflammation.

PATIENTS AND METHODS

BAL was performed in 32 patients with active pulmonary TB, and the recovered BAL fluid (BALF) was examined for concentrations of TNF-alpha and its soluble receptor forms, IL-1beta, and IL-1RA. Patients were classified into two groups: group 1, patients with a large cavity (> or = 4 cm) on chest radiographs (n = 15); and group 2, patients with a small cavity (< 4 cm; n = 3) or no cavity (n = 14) on chest radiographs.

RESULTS

The concentrations of TNF-alpha, IL-1beta, and IL-1RA in BALF were significantly higher in group 1 patients than in group 2 patients before standardization. The difference was also statistically significant for TNF-alpha and IL-1beta after standardization with urea. Furthermore, group 1 patients had significantly higher ratios of TNF-alpha to sTNF-RI and sTNF-RII and IL-1beta to IL-1RA compared with group 2 patients.

CONCLUSIONS

These findings suggest that the relative abundance of TNF-alpha and IL-1beta associated with imbalances of secretion of soluble TNF-alpha receptor forms and IL-1RA may have caused tissue necrosis leading to cavity formation in patients with active pulmonary TB.

Pulmonary mechanics in patients with prolonged mechanical ventilation requiring tracheostomy

This study was performed to assess the changes in pulmonary mechanics before and after tracheostomy in patients with prolonged mechanical ventilation and to detect pre-tracheostomy physiologic factors that predict the outcome of weaning from mechanical ventilation. Pulmonary mechanics were recorded before and after tracheostomy in 20 patients. Work of breathing, mean airway resistance and pressure/time product showed no significant differences after tracheostomy. Peak inspiratory pressure was significantly reduced (pre 33.4 +/- 11.8 vs post 28.6 +/- 9.2 mmHg). There was no difference in age or duration of mechanical ventilation between two different groups according to the outcome (weaned and not-weaned). Pre-tracheostomy intrinsic positive end expiratory pressure (PEEPi) was significantly lower in the weaned group (1.1 +/- 1.6 vs 2.7 +/- 1.4 mmHg). A significant difference was also found in pre-tracheostomy compliance (Cstatic) (47.3 +/- 36.9 vs 28.8 +/- 16.5 ml/cmH2O). We concluded that tracheostomy changed pulmonary mechanics very little except for a fall in peak inspiratory pressure. Patients who had better underlying lung mechanics (higher Cstatic and lower PEEPi) had better chances of weaning from mechanical ventilation after tracheostomy.

Soluble TNF-alpha receptor and IL-1 receptor antagonist elevation in BAL in active pulmonary TB

Accumulating evidence suggests that patients with active pulmonary tuberculosis (TB) have an alveolar inflammation resulting in the release of tumour necrosis factor (TNF)-alpha and interleukin (IL)-1beta in bronchoalveolar epithelial fluid. It was proposed that the levels of these cytokines would correlate with clinical status parameters (extent of pulmonary involvement, fever, and body weight loss) and that their naturally occurring inhibitors would be concomitantly released in the local inflammatory sites. To test this hypothesis lung epithelial lining fluid (ELF) obtained by bronchoalveolar lavage and serum were collected from 29 patients with active pulmonary TB and 15 healthy subjects to determine the levels of these variables using a sandwich enzyme-linked immunosorbent assay (ELISA). ELF levels of TNF-alpha, soluble (s)TNF receptor I (RI), sTNF-receptor II (RII) and interleukin-1 receptor antagonist (IL-1RA) but not IL-1beta, and their serum levels except for sTNF-RII and IL-1beta were significantly higher in TB patients. Nevertheless, only ELF levels of TNF-alpha and IL-1beta were significantly correlated with disease status. No correlation was found between TNF-alpha levels and those of sTNF-RI and sTNF-RII, nor between IL-1beta and IL-1RA in ELF and serum of TB patients, although there was a significant correlation between sTNF-RI and sTNF-RII levels both in ELF and serum. These findings suggest local release of tumour necrosis factor-alpha and interleukin-1beta and a correlation with disease status. Soluble tumour necrosis factor-alpha receptors and interleukin-1beta receptor antagonist, although increased in lung epithelial lining fluid and serum in tuberculosis patients, were not correlated with tumour necrosis factor-alpha and interleukin-1beta or with disease status.

Comparison of indoor allergens, allergic scores, and demographic data in Taiwanese adults with asthma or allergic rhinitis, or both

We examined the relationships between exposure to different indoor allergens and demographic factors in 515 adult Taiwanese patients with allergic diseases such as asthma and rhinitis. Patients who had positive screening results on an immunoglobulin E (IgE) test were recruited from the outpatient clinics of Chang Gung Memorial Hospital. Patients were divided into the following three groups: asthma (n = 332), combined asthma and allergic rhinitis (n = 165), and allergic rhinitis (n = 18). Serum samples were analyzed for IgE by enzyme-linked immunosorbent assay. Significantly elevated titer of dust mite-specific IgE were found in all three groups, with markedly higher levels in the combined asthma and allergic rhinitis group (p < 0.05). Allergen scores were significantly related to the demographic variables of older age (> or = 65 years), female gender, and spring season, with significantly lower scores (p < 0.05). No significant difference in allergen scores was found among cigarette smoking subjects and subjects from residential areas. Multiple linear regression analysis revealed significant allergic contributors to be, in order of importance, age, gender, and atopic disease category. We conclude that mite allergen exposure is the most significant factor associated with asthma and/or allergic rhinitis in Taiwan. Younger subjects and males had a higher rate of asthma and/or allergic rhinitis.

The effects of two different cisplatin-based chemotherapy regimens on advanced non-small cell lung cancer

BACKGROUND

Many different cisplatin-based regimens have been used on advanced non-small cell lung cancer (NSCLC) in previous studies but there have been few such references in Taiwan. In this study, we evaluated the efficacy and toxicity of two different regimens including 5-Fluorouracil, Leucovorin, Etoposide and cisPlatin (FLEP) and cisPlatin, Etoposide and Mitomycin (PEM) in the treatment of patients with advanced NSCLC.

METHODS

We retrospectively analyzed the records of 44 patients with NSCLC who met the selection criteria from February 1995 through April 1998. All of them were confirmed, using histologic tests, that they were in advanced stages, i.e. stage IIIB or IV. Twenty-two patients received FLEP and 22 patients received PEM.

RESULTS

Three patients with FLEP therapy and 3 patients with PEM therapy had partial response. No patient had complete response. The response rate was 13.6% in both groups, respectively. The median survival was 160 +/- 30 (median + SD) days for patients with FLEP therapy and 263 +/- 104 days for patients with PEM therapy. The factors that were associated with longer survival in all patients included response (Stable Disease vs Disease Progression p = 0.004, Partial Response vs Disease Progression p = 0.047) and regimen of chemotherapy (PEM vs FLEP p = 0.008). The major clinically significant toxicity was myelosupression.

CONCLUSION

The responses to regimens, FLEP and PEM, were low in our study groups that might be due to the low dose of cisplatin and etoposide in our regimens. The patients with response to chemotherapy and PEM therapy had longer median survival than those who underwent FLEP therapy.

Spontaneous variability of arterial oxygenation in critically ill mechanically ventilated patients

OBJECTIVE

To assess the magnitude of spontaneous variability of arterial oxygenation and oxygen tension-based indices over time in medical intensive care unit (ICU) patients and to study whether high positive end-expiratory pressure (PEEP) or inverse inspiratory-to-expiratory (I:E) ratio ventilation (IRV) results in a greater variability than low PEEP with conventional I:E ratio ventilation.

DESIGN

Prospective study.

SETTING

Medical ICU in a tertiary medical center.

PARTICIPANTS

23 patients requiring a pulmonary artery floating catheter for hemodynamic monitoring.

INTERVENTION

After being completely sedated, patients were randomized to receive pressure-control ventilation at setting A: high PEEP (15 cm H2O) with conventional I:E ratio (1:2) and setting B: inverse I:E ratio (2:1) with low PEEP (5 cm H2O) alternately, and then at setting C: low PEEP (5 cm H2O) with conventional I:E ratio (1:2). Each ventilation setting lasted 1 h.

MEASUREMENTS AND RESULTS

The arterial and mixed venous blood samples were measured simultaneously at baseline (time 0), and at 15, 30, 45, and 60 min thereafter. The coefficient of variation (CV) of arterial oxygen tension (PaO2) over time was 5.9 % for setting A, 7.2 % for setting B, and 6.9 % for setting C. ANOVA showed no significant differences in CVs of PaO2 between the three settings. Oxygen tension-based indices, alveolar-arterial oxygen difference (A-aDO2) and PaO2/ PAO2 (alveolar oxygen tension), displayed CVs equal to that of PaO2; the CV of A-aDO2/PaO2 was significantly greater than that of PaO2.

CONCLUSIONS

In critically ill medical ICU patients, despite sedation, the spontaneous variability in PaO2 over time is substantial. A high PEEP or IRV does not contribute to the increased variation in PaO2.

Serodiagnosis of tuberculosis by enzyme-linked immunosorbent assay for anti-A60 and anti-A38

BACKGROUND

For early diagnosis of tuberculosis (TB), especially in the patients without adequate sputum specimens for examination, we found a simple, rapid and inexpensive method among many current available diagnostic tools, the enzyme-linked immunosorbent assay (ELISA). To investigate the diagnostic effectiveness of this method, we applied ELISA for detection of antigen 60 IgG and IgM as well as antigen 38 IgG antibodies at Chang Gung Memorial Hospital from April 1995 through June 1996.

MATERIALS AND METHODS

Sixty-seven patients were enrolled and divided into 3 groups, Group A (n = 24), patients with positive sputum acid-fast stain; Group B (n = 18), patients with lung cancer and negative sputum acid-fast stain; and Group C (n = 25), patients with chest roentgenogram (CXR) which were suggestive of TB but with negative acid-fast stain results or no sputum for examination.

RESULTS

For the A60 IgG antibody, we found a sensitivity rate of 91.7% for Group A and Group B, and 85.7% for Group C as well as an overall sensitivity of 89.5% but with lower specificity. For the A60 IgM antibody, a lower sensitivity (37.5%, 14.3%, 28.9%, respectively) was found but with higher specificity. For the A38 IgG antibody, we found a lower sensitivity (40%, 11.1%, 31%, respectively) but with higher specificity (100%, 71.4%, 90%, respectively).

CONCLUSION

With a high sensitivity but low specificity for diagnosis of TB, A60 IgG ELISA could be used as a rapid, simple screening test for patients with results suggestive of TB, especially in those who had no sputum or had negative sputum acid-fast stain results. Otherwise, A60 IgM or A38 IgG ELISA, with a high specificity, could be used as a reliable test in the diagnosis of pulmonary TB when the result is positive. In summary, although ELISA is a simple, rapid, inexpensive method, it is helpful but limited in the diagnosis of pulmonary TB.

Oxygen, arterial blood gases and ventilation are unchanged during dialysis in patients receiving pressure support ventilation

This study was undertaken to observe whether dialysis-induced alveolar hypoventilation and arterial hypoxaemia occur during bicarbonate haemodialysis in patients receiving partial mechanical support with pressure support ventilation. Nineteen patients admitted to the medical intensive care unit requiring mechanical ventilation and haemodialysis were enrolled. Arterial blood gas, white blood cell (WBC) count, minute ventilation, respiratory rate, breathing pattern and blood pressure were measured according to the following time schedule: pre-dialysis (time 0), and at 15, 30, 60, 120, 180, 240 min thereafter. Results showed that, with the use of cuprammonium dialyser, the WBC count dropped immediately and reached the nadir 15 min after haemodialysis. Thereafter, it recovered and overshot the pre-dialysis values until the end of dialysis. The bicarbonate dialysate indeed resulted in rapid and significant metabolic alkalosis. However, no decrease of PaO2 occurred throughout haemodialysis. The tidal volume, minute ventilation and breathing pattern remained stable during haemodialysis. We conclude that neither dialysis-induced alveolar hypoventilation nor arterial hypoxaemia developed during bicarbonate dialysis in patients mechanically ventilated with the pressure support ventilation.

Elastance of the pleural space: a predictor for the outcome of pleurodesis in patients with malignant pleural effusion

BACKGROUND

In patients who have malignant pleural effusion, it is difficult to diagnose trapped lung before thoracoscopy, thoracostomy, and drainage of the effusion. Predicting the outcome of pleurodesis in patients who have malignant pleural effusion without trapped lung is also difficult.

OBJECTIVE

To investigate the factors that may be useful in diagnosing trapped lung and predicting the outcome of pleurodesis.

DESIGN

Prospective cohort study.

SETTING

University medical center.

PATIENTS

65 patients with symptomatic malignant pleural effusion.

INTERVENTION

A chest tube was inserted for drainage of the effusion, and pleurodesis was done using bleomycin as the sclerosant.

MEASUREMENTS

The pH and glucose levels of the effusion and the elastance of the pleural space (defined as the decline in pleural fluid pressure in cm H2O after removal of 500 mL of effusion) were measured. The outcome of pleurodesis was evaluated 1 month after the chest tube was removed.

RESULTS

Patients with an elastance of 19 cm H2O or more had a higher incidence of trapped lung (11 of 14 patients) than did those with an elastance less than 19 cm H2O (3 of 51 patients) (P < 0.001). None of the 14 patients with an elastance of 19 cm H2O or more and none of the 14 patients with a trapped lung had successful pleurodesis. Forty-two of 43 patients with an elastance less than 19 cm H2O who did not have a trapped lung had successful pleurodesis. Elastance seemed to be the best predictor for trapped lung and outcome of pleurodesis, although outcome was also correlated with pH and glucose levels of the effusion. Low-dose bleomycin (30 mg) is as effective as the usual dose of bleomycin (60 mg) for pleurodesis.

CONCLUSION

In patients with symptomatic malignant pleural effusion, measurement of the elastance of the pleural space is a simple and effective method for the diagnosis of trapped lung and prediction of the outcome of chemical pleurodesis with bleomycin.

Comparison of the clinical diagnostic value between pleural needle biopsy and analysis of pleural effusion

BACKGROUND

Many diseases are manifested by pleural effusion. Chest echo-guided thoracentesis and pleural biopsy are the two major procedures in diagnosing pleural effusion, but the validity is still under debate. To compare the diagnostic value of echo-guided pleural biopsy with pleural effusion analysis, we designed this retrospective study.

METHODS

We reviewed 176 patients who underwent both procedures at Chang Gung Memorial Hospital from 1989 to 1990.

RESULTS

Sixty-six patients (38%) were diagnosed with malignant pleural effusion which was proven by needle biopsy (55%) or effusion cytologic analysis (64%). Combining both methods increased the diagnostic rate to 88%. Among the 76 patients who were diagnosed with tuberculous pleural effusion, only 18% were proven by pleural biopsy and 20% by pleural effusion culture. The other cases were confirmed by sputum exam (34%) or successful therapeutic trial (41%). The remaining 19 patients (11%) were diagnosed as undeterminate etiology.

CONCLUSION

Combined pleural biopsy with cytologic analysis of the pleural effusion was more beneficial than any single method in identifying malignant pleural effusions, and repeated pleural biopsy increased the positive rate from 49% to 55% in our study.

Multiple brushings with immediate Riu's stain via flexible fibreoptic bronchoscopy without fluoroscopic guidance in the diagnosis of peripheral pulmonary tumours

BACKGROUND

Accurate diagnosis of peripheral pulmonary lesions usually relies on fluoroscopic guided procedures. As fluoroscopy is not routinely available in many respiratory units, an approach not using fluoroscopy but with a high diagnostic yield is highly desirable.

METHODS

Immediate cytological examination of multiple brushings using Riu's stain, a modified Wright's stain, was performed in 38 patients with peripheral pulmonary lesions not visible at bronchoscopy. The results were compared with the final diagnoses determined by histological examination or subsequent Papanicolaou staining of cytological specimens and clinical course.

RESULTS

Of the 38 patients 29 were subsequently confirmed to have a malignant tumour. Our method provided a diagnosis of malignancy in 86% of these lesions. The accuracy (91%) and sensitivity (88%) were higher for lesions > 3 cm in diameter than for those of diameter < or = 3 cm (87% and 83%). There were no false positive results. The 29 lesions correctly diagnosed as malignant by Riu's stain required significantly fewer brushings (mean (SD) 3 (2)) than the nine benign lesions (5 (4)).

CONCLUSIONS

This technique provides a high diagnostic yield, avoids the need for fluoroscopy, and is probably safer than percutaneous biopsy.

Ovarian hyperstimulation syndrome with minimal ascites and massive pleural effusion: report of a case

A 30-year-old woman was admitted to the hospital due to bilateral massive pleural effusion and right lung collapse with severe respiratory distress. She had been undergoing gamete intrafallopian transfer (GIFT) following three years of primary infertility. Ovarian stimulation was done with pure follicle stimulating hormone (FSH) and human menopausal gonadotropin (hMG) under pituitary suppression with leuprolide acetate. Bilateral chest pain and progressive dyspnea occurred six days after preovulatory oocytes with washed motile sperms were transferred laparoscopically to the fallopian tubes. Chest radiography, sonography and computed tomography revealed a massive right pleural effusion with right lung collapse, and a mild left pleural effusion. Abdominal sonography revealed minimal ascites. Supportive therapy including fluid supply and albumin infusion failed to improve the respiratory distress. A tube thoracostomy was performed, resulting in rapid reexpansion of the lung. The respiratory distress improved markedly after drainage of 6,800 mL of pleural effusion over 7 days. Massive serosanguineous pleural effusion with minimal ascites is unusual in ovarian hyperstimulation syndrome (OHSS). Tube thoracostomy is a safe and effective treatment for massive pleural effusion and lung collapse in the case of OHSS.

Interferon-gamma and tumor necrosis factor-alpha promote the binding of dendritic cells to fibronectin

Connective tissue dendritic accessory cells (DC) accumulate at sites of extracellular matrix (ECM) deposition. The adherence of DC to purified ECM proteins was examined. Splenic and pulmonary DC were purified from Lewis rats and incubated on slides coated with fibronectin (FN), laminin (LN), or collagen (COLL) types I, III and IV. In other experiments, DC were pre-incubated with selected proinflammatory cytokines (IL-1, IL-2, IFN-gamma, TNF-alpha) in order to determine their abilities to modulate cell adherence to ECM. Both splenic and pulmonary DC showed dose-dependent binding to FN that was inhibited by the synthetic peptide arg-gly-asp-ser. There was minimal DC binding to LN or COLL. Pretreating DC with IFN-gamma or TNF-alpha enhanced DC binding to FN but did not increase binding to LN or COLL. IL-1 and IL-2 had no demonstrable effect on DC binding to ECM. Our results suggest that FN is a critical ligand for DC in their binding to the ECM. IFN-gamma and TNF-alpha increase adherence of DC to FN and may promote their accumulation in the lung during inflammation.

Intrathoracic tracheal dimensions and shape changes in chronic obstructive pulmonary disease

Changes in intrathoracic tracheal dimensions and shape in patients with chronic obstructive pulmonary disease (COPD) are commonly noted, but the cause is not clear. This study reveals a significantly larger lateral tracheal diameter (LTD) in patients with COPD. The larger LTD has a significant positive linear correlation with a larger lateral chest diameter. This finding supports the hypothesis that in patients with COPD the increase in volume of both lungs pressing on the mediastinum will exert a lateral pressure on the trachea, resulting in a decrease in frontal and an increase in the lateral trachea diameter. Patients with COPD have a smaller tracheal index: FTD/LTD (FTD: frontal tracheal diameter). Saber-sheath trachea (tracheal index < 2/3) is a specific radiographic diagnostic parameter for the diagnosis of COPD (specificity, 92.9%), although the sensitivity (39.1%) is low.

Repository dexamethasone in the treatment of acute bronchial asthma

Fifty-two patients with acute asthma requiring immediate therapy but not hospitalization were studied in an emergency department following conventional therapy with bronchodilators. After discharge, the patients were treated with a controlled regimen of long-acting theophylline and beta-agonist inhalation as necessary. They were randomly assigned to one of three groups using a double blind model. Group A received intramuscular and oral placebos. Group B received intramuscular dexamethasone injection along with oral placebo treatment. Group C received oral dexamethasone by a tapering schedule associated with placebo intramuscular injection. Follow-up was carried out 7 days after the treatment in the emergency room. There were no significant statistical differences in the relapse rate among the three groups. Those patients who received oral or intramuscular dexamethasone had a decrease in the need for beta-agonist inhalation and fewer respiratory symptoms. However, there was no significant statistical difference between groups B and C. It was concluded that repository steroids could reduce the respiratory symptoms and frequency of beta-agonist usage as effectively as oral steroid treatment. However, the steroids do not improve the relapse rate in patients with only mild symptoms.

Whole lung tuberculosis. A disease with high mortality which is frequently misdiagnosed

The mortality rate of WLTB was significantly higher than non-WLTB in 45 of 516 cases of PTB in a 24-month period. There is no known underlying disease predisposing to WLTB. Clinically, the patients were significantly more toxic and had lower serum albumin and hemoglobin levels than non-WLTB patients. They had a lower rate of positive PPD tuberculin skin tests. The chest roentgenograms revealed three patterns: (1) DBS type in 15--all with multiple or diffuse opacities with or without cavitations; (2) DHS type in 20--eight with typical miliary lesions and 12 with atypical miliary patterns; (3) combined focal PTB and DHS type in ten. We found that atypical chest roentgenographic patterns were common in WLTB and frequently led to misdiagnosis. The delayed diagnosis and treatment of this advanced disease resulted in the high mortality. Early, empirical antituberculosis chemotherapy is indicated and life-saving.

Acute renal failure and severe thrombocytopenia induced by rifampicin: report of a case

We report on a patient who developed life-threatening thrombocytopenia and acute renal failure after the reinstitution of rifampicin therapy for pulmonary tuberculosis. This combined reaction is rarely reported. Supportive treatment and withdrawal of rifampicin led to complete recovery. The increased incidence of drug-resistant tuberculosis and the need for the reintroduction of rifampicin therapy may lead to more such reactions being observed.

Pulmonary manifestations of Staphylococcus aureus septicemia

This study includes 140 episodes (138 cases) of Staphylococcus aureus septicemia, made up mostly of community-acquired, nonintravenous drug abuse (nonIVDA) cases. Unlike other series, injury wounds and skin or soft tissue infections were the most common sites of primary infection. In spite of a different patient population and lack of cases with tricuspid valvular endocarditis, the lungs were still the most common site of secondary infectious foci and most developed within two weeks of onset of the septicemia.

Thoracic actinomycosis--review of 9 cases

Nine cases of thoracic actinomycosis treated in the period from 1976 to 1990 were reviewed. Among them, 4 cases were children. The clinical symptoms and laboratory examinations were non-specific. Chest roentgenographic manifestations including nodular (3 cases), infiltrations (4 cases), and infiltrations with pleural changes (2 cases) were also non-specific. Chest wall masses were noted in four patients. There were no cases correctly diagnosed on admission. The diagnosis of thoracic actinomycosis was made from thoracotomy in 6 cases, from culture of chest wall mass incisional specimens in 2 cases and from bronchoscopic biopsy in 1. All the patients received antibiotics, however the varied duration of postoperative antibiotics did not change the outcome. No mortality or recurrence was noted in our 9 patients with a mean follow-up of 1.9 years (from 2 months to 6 years.) We conclude that surgical intervention is still the cardinal method for diagnosis and treatment. Establishment of the role of postoperative antibiotics will need further prospective study. The prognosis of thoracic actinomycosis is fairly good.

Mycoplasma pneumoniae pneumonia: clinical analysis of 45 cases

Mycoplasma pneumoniae (M. Pneumoniae) is a primarily pathogen of the respiratory tract. The clinical characteristics, laboratory findings, and roentgenographic patterns of 45 patients with serologically proven M. pneumoniae pneumonia admitted to Chang Gung Hospital from 1981 to 1989 have been reviewed. There were 23 males and 22 females. Forty-one (91%) were below 40 years old and 13 patients (29%) were below 5 years old. Fever, cough and chest rales were the most common symptoms and signs. A transient mild elevation of liver enzymes was seen in 33% of the patients, most of whom were below the age of ten (73%). A leukocyte count over 15,000/cu mm was not rare (16%). Roentgenographic features included unilateral infiltration (84%), lower lobe predominance (60%), and either confluent (56%) or patchy (33%) consolidation. Pleural effusion occurred in 24% of the patients. Complete resolution of chest roentgenography took from 8 to 42 days with a mean of 20 days. The response of fever to treatment with erythromycin took from 1 to 6 days with a mean of 3 days. There were no life threatening pulmonic or extrapulmonic complications.

Pneumonia preceding respiratory failure. A rare, easily misleading clinical manifestation in adult Arnold-Chiari malformation

A 47-year-old woman was admitted for bilateral lower lobe pneumonia with respiratory distress. Two episodes of respiratory failure developed despite improvement of pneumonia after antibiotic chemotherapy. Loss of consciousness and quadriplegia accompanied the last episode of respiratory failure. Arnold-Chiari malformation type 1 was diagnosed and a suboccipital craniectomy was performed. The neuromuscular and respiratory disorders greatly improved after operation. We believe that ACM 1 should be considered when an adult develops unexpected respiratory failure after improvement of the primary pulmonary condition. This disease is potentially treatable by surgical management, and if it is misdiagnosed, will be fatal.

Respiratory failure of acute organophosphate and carbamate poisoning

Respiratory failure (RF) developed in 43 (40.2 percent) of 107 patients with acute organophosphate or carbamate poisoning; 22 (51.2 percent) died. The 64 patients who did not develop RF survived. All cases of RF developed within 96 hours after poisoning: within 24 hours in 35 patients (acute onset) and between 24 and 96 hours in eight patients (subacute onset). Severity of poisoning was the primary determinating factor for RF. Cardiovascular collapse and pneumonia were also associated with RF. In 19 patients with cardiovascular collapse, 17 had acute onset of RF and two had subacute onset. In 28 patients with pneumonia, 17 developed acute onset of RF and eight developed subacute onset. No organophosphorus compound caused RF more frequently than another. The duration of ventilator support for subacute RF was significantly longer than for acute RF (287 +/- 186 vs 115 +/- 103 hours, p = 0.02). The use of pralidoxime did not reduce the incidence of RF. We found that severity of poisoning, cardiovascular collapse, and pneumonia were the predisposing factors to RF. The golden time for treatment of acute organophosphate or carbamate poisoning was the initial 96 hours. No RF occurred after this time. Aggressive treatment and prevention of the above three factors will reduce the incidence of RF, or in other words, reduce the mortality.

Modulation of kidney cell protein degradation by insulin

Insulin is an established regulator of intracellular proteolysis in several mammalian tissues but little is known about its role in the kidney. The present study was undertaken to determine whether insulin influences protein degradation in isolated rat renal proximal tubules and to investigate its mechanism of action in cultured proximal-like tubular epithelial cells from the opossum kidney. Long-lived protein degradation was determined from the release of carbon 14-labeled valine from previously labeled cellular protein under conditions designed to minimize label reutilization. In isolated tubules, the mean control rate of proteolysis was 2.18% per hour, indicating an appreciable turnover of cellular protein. Insulin (10(-6) mol/L) decreased the rate by 23%. In cultured kidney cells, the rate of protein degradation averaged 1.25% per hour in the presence of serum and 1.68% per hour in its absence, an increase of 34%. High insulin concentrations suppressed this acceleration completely, and physiologic levels inhibited it partially. No evidence was obtained to indicate that insulin action is mediated through stimulation of Na(+)-H+ antiport or through increased amino acid utilization. Ammonium chloride, however, strongly attenuated the serum deprivation response and the inhibitory effect of insulin. The exact mechanisms whereby insulin inhibits proteolysis is not known, but these findings are consistent with an inhibitory action of insulin on the lysosomal pathway.

Treatment for collapsed lung in critically ill patients. Selective intrabronchial air insufflation using the fiberoptic bronchoscope

A new, simpler method to re-expand collapsed lungs was introduced in 14 procedures in 12 critically ill patients. To close the bronchus, we wedge the fiberoptic bronchoscope into each segment or subsegment of the collapsed lung instead of using a balloon cuff. Room air was then insufflated into the atelectatic alveoli after repetitive sputum suctioning and bronchial washing with normal saline solution. Complete re-expansion was achieved in 12 of the 14 procedures and partial in two. The average alveolar-arterial oxygen pressure difference (P[A-a]O2) declined from 217.5 before the procedure to 200.3, 150.0 and 152.2, respectively at 30 minutes, 12 hours and 24 hours after. There were no complications.

Fever characteristics in tuberculosis--clinical observation in 597 cases

Fever characteristics were analyzed in 597 cases of tuberculosis diagnosed by positive culture for mycobacteria tuberculosis admitted to Chang Gung Memorial Hospital between March 1984 and February 1986. Among them, fever was noted in 356 cases (60.0%). Several factors were predisposing to the absence of fever: having a past history of tuberculosis (p less than or equal to 0.01), having a limited lung lesion (p less than 0.05), having an infection with isoniazide (INH) resistant strain (p less than 0.05). Fever typically developed in the late afternoon or evening in 66% of the cases, and this typical fever was significantly more common in patients less 60 years of age (p less than 0.05). The fever was low grade (less than 38.5 degrees C) in 59% of the cases. Among the 137 cases whose fever courses were completely monitored in the hospital, there were 30 cases (22%) whose fever subsided within 3 days after the start of antituberculous chemotherapy, 102 cases (74%) within 1 week and 128 cases (93%) within 2 weeks. Fever resolved within 4 weeks in all but one patient. There was no clinical factor predisposing to the delay of time for the fever to resolve including sex, age, immunocompromised condition, having a past history of tuberculosis, the infectious site(s) of tuberculosis, the extent of pulmonary involvement, the presence of cavitation in pulmonary involvement, and infection with resistant strains.

Altered potassium flux and myocardial dysfunction during sepsis

Untreated septic shock results in depletion of extracellular fluid, cellular swelling, increased intracellular sodium, and decreased intracellular potassium concentrations in primate skeletal muscle. The Langer rabbit heart interventricular septal preparation was used to determine whether similar changes occur in cardiac muscle during sepsis. Rabbit septa (n = 17) were perfused with control and septic rabbit plasma plus red blood cells. Tissue contractility (developed tension [DT] and rate of tension change [dP/dt]) was followed, plasma cations were measured (Na+, K+, Ca2+, H+), perfusion pressure (PP) was monitored, and 42K efflux was determined. The effect on 42K efflux caused by the addition of potassium chloride to control plasma was determined. During perfusion with septic plasma there was significant decline of septal function (P less than 0.001). In 12/17 experiments DT fell 77.8 +/- 21.4% and dP/dt fell 75.8 +/- 24.8% from control values (means +/- 1 SD). All septa recovered when perfusion with control plasma was resumed. If [K+] was increased in control plasma during 42K washout, the percentage increase of effluent counts per minute per minute correlated with the percentage rise of control plasma [K+] (r = 0.95, P less than 0.001). During perfusion with septic plasma there was no similar correlation (r = 0.277). 42K efflux increased during septic plasma perfusion independent of the differences between control and septic plasma [K+], demonstrating abnormal myocardial K+ efflux. An abnormal efflux of K+ is seen during septic plasma perfusion similar to that described in primate skeletal muscle. It is associated with and may be a mechanism of action for the observed fall of contractility.

Myocardial depression. The effect of Ca++ and calcium flux during sepsis

Previous studies from this laboratory described myocardial depression in an arterially perfused rabbit interventricular septum following perfusion with acute septic plasma. Calcium is critical for maintenance of cardiac contractility on a beat-to-beat basis. We have investigated calcium flux in the septal tissue to determine whether altered calcium flux explains the impaired cardiac function during sepsis. Twenty-two rabbit septa were perfused with control and septic perfusate (cryo-precipitated plasma + RBCs) and calcium flux determined in seven experiments. Perfusate cations (Ca++, Na+, K+, and H+) were measured, tissue function and arterial pressure were monitored. Developed tension decreased 46%, acceleration of tension change fell 42%, and arterial pressure decreased 26%, all highly significant. All septa recovered after return to control perfusate. The septic perfusate Ca++ was significantly lower than control perfusate, while K+ and H+ were significantly elevated. Ion flux studies, however, could not demonstrate altered calcium flux associated with the depressed contractility.

The role of prostacyclin and thromboxane in sepsis and septic shock

Prostacyclin, or prostaglandin I2 (PGI2), and thromboxane A2 (TXA2) are potent, endogenously produced, vasoactive substances that have been implicated as mediators in the pathophysiologic nature of septic shock. We investigated the contribution and production of PGI2 and TXA2 in sepsis and septic shock, using an intact rabbit model and an in vitro rabbit isolated cardiac perfusion model. Continuous hemodynamic monitoring of both experimental models, along with serial radioimmunoassays of the metabolites of PGI2 and TXA2, indicated that myocardial depression is a common finding in subjects with septic shock and that septic shock causes a suppression of PGI2 production while augmenting TXA2 production. In addition, PGI2 and TXA2 were mediators of some cardiovascular changes in septic shock but were themselves not the toxic factor(s) responsible for the associated myocardial depression.