A b s t r a c t s From the L i t e r a t u r e

Selec ted by Mar t i n J. Tob in

Adult Respiratory I~istress Syndrome: Prognosis After Onset. Fowler AA. Itamrnan RF. Zerbe GO. et el. Am Rev Respir Dis 132:472, 1985.

In 88 patients with the adult respiratory distress syqdrome, clinical, laboratory, cardiopulmonary, and demographic data collected on the day of the onset of the syndrome were used to identify predictors of survivorship and mortality. Variables that individually were associated with mortality were then analyzed simultaneously by the Cox proportional hazards function and by multiple discriminant function using a step-up procedure. I'-our variables taken singly were signifi- cantly associated with mortality. These were the presence of less than 10% band forms on the initial peripheral blood smear, persistent acidemia with arterial pH less than 7.40, calculated I-iCO~ less than 20 mg/dL, and blood urea nitro- gen greater than 65 mg/dL. After eliminating those variables that did not comributc significantly to mortality in the presence of the others, only low band forms, low pH, and low HCO~ were significantly associated with increased mortality. These findings illustrate the continued high mortality rate in the syndrome and indicate possible systemic aberrations that contribute to its severity.

Collagenese in the Lower Respiratory Tract of Patients With Adult Respiratory Distresis Syndrome. Christner P, Fein A. Golaherg S. et al, Am Rev Respir Dis 131:690, 1985.

Collagenasc activity in the bronchoalveolar lavage (BAL) of patients with adult respiratory distress syndrome (ARDS) was measured against Type i collagen (17 patients) and against Type II! collagen (13 patients). Serin¢ protease activity was also measured against Type III collagen (13 patients). Type I collagcnase activity was detectable in 12 of 17 and Type II! collagenase was detectable in 12 of 13 patients with ARDS. The ten control subjects had no detect- able Type I or Type i[I eollagenase activity. Total and differential white cell counts were analyzed in the lavage fluid, AIIhough the total counts did not differ between patients with ARDS and control subjects, the percentage of neutrophils was increased more than 25-fold, and the per- centage of macroph;tges was reduced almost tenfold it, the ARDS patients. Serial collagenase activity was followed in one ARDS survivor, In this patient Type ill collagenase activity peaked before the Type I coltagenase activity or serine proteasc activity reached their maximums. Both the latter enzyme activities paralleled the total recoverable cells in the BAL.

Causes of Mortality in Patients With the Adult Respiratory Distress Syndrome, Montgonler)" AB. Stager A~A. Carrico CJ. et el. Am Rev Respir Dis 132:485, 1985.

This study analyzed the factors causing and contributing to death in patients with the adult respiratory distress syndrome (ARDS). Two hundred seven patients were pro- spectively identified as being at risk for development of ARDS. Forty-seven patients developed ARDS, and the remaining 160 patients were used as a comparison control group. The severity of dysfunction in eight organ systems and the presence of sepsis syndrome were determined by chart review after discharge or death. Sepsis syndrome was specifi- cally defined by signs and laboratory tests reflecting infection or inflammation plus evidence of a deleterious systemic effect (hypotension, reduced systemic vascular resistance, or unex- plained metabolic acidosis). Mortality was 68% in the ARDS group compared to 34% in the control group (P < .005). Only 16% (5 of 32) of deaths in the ARDS group were from irreversible respiratory failure. Most deaths in the first 32 days after entry into the study could be attributed to the underlying illness or injury. The majority of late deaths were related to sepsis syndrome, Of the 22 patients with ARDS who died after three days, 16 (73%) met our criteria for sepsis syndrome. There was a sixfold increase in sepsis syndrome after ARDS compared with that in the control group (P < .001 ), When sepsis syndrome preceded the ARDS, the abdo- men was the predominant source, but when sepsis syndrome occurred after the onset of ARDS there was usually a pulmonary source. Our findings indicate that sepsis syn- drome, rather than respiratory failure, is the leading cause of death in patients with ARDS.

Complications of Right Heart Catheterization: A Prospec- tive Autopsy Study. Conners AFJr , C'asteh" RJ. Farhat NZ. et el. Chest 88:4;567. 1985.

The purpose of this study was to characterize the type and prevalence of abnormalities associated with right heart cath- eterization. We performed detailed postmortem examina- tions of 32 consecutive patiepts brought to autopsy with a right heart catheter in the pulmonary artery. Thrombosis (17 patients, 53%), hemorrhagic lesions (25 patients. 78%), and intimal fibrin deposition (21 patients, 66%) were found at sites along the entire path of the catheter. Twenty-nine patients (91%) had either thrombosis, hemorrhage, or both. While the superior vena cave was the most common site for all lesions, seven patients had thrombosis involving the cham- bers and valves of the heart, and four had thrombosis involving the pulmonary artery. The incidence of thrombosis was significantly higher after 36 hours of catheterization (P < .05). All five patients with thromboemboli in the more proximal pulmonary arteries had catheter-related thrombo- sis. We conclude that there is a high prevalence of thrombotic and hemorrhagic lesions in patients dying with pulmonary catheters in place; that the risk of thrombotic complications increases with duration of catheterization; and that patients with catheter-related thrombosis are at increased risk of thromboemboli to the proximal pulmonary arteries.

Evaluation of the Portable Chest Roentgenogram for Quan- titettng Extravascular Lung Water in Critically III Adults. Halperin BD, Fee/e), TI'Y, Mihm FG, et aL Chest 88:5;649, 1985.

The diagnosis of pulmonary edema is frequently made from characteristic findings on the chest roentgenogram that

Journal of Critical Care, Vet 1, No 1 (March), 1986: pp 57-63 57

58 ABSTRACTS

suggest an increase in lung water. Optimal radiographic technique depends on a cooperative upright patient, which is not possible with most critically ill patients. These patients may also have multiple radiographic abnormalities that make interpretation of the chest roentgenogram difficult. The ability of portable chest roentgenograms to accurately iden- tify the presence of excess lung water and monitor changes in lung water has not previously been evaluated in critically ill adults who are intubated and ventilated and in the supine position when the films are exposed. In 12 patients the pulmonary edema seen on portable chest roentgenograms was given a score (0 to 390 points), which was then compared with a determination of extravascular lung water using the thermal-dye indicator dilution technique. A linear correla- tion was observed (r - ,51, P < .05, n - 73). Evaluation of a change in radiographic score v a change in lung water showed no linear correlation (r - .I, P > .05). While portable chest roentgenograms exposed under the conditions described were a useful technique for demonstrating pulmonary edema, they were not accurate in monitoring modest changes in lung water in critically ill patients.

Efficacy of Chest Radiography in Respiratory Intensive Care Unit: A Prospective Study. Bekeme)'er WB, Crape RO, Calhoun S. et aL Chest 88:5;691, 1985.

A prospective study of chest radiographic examinations in a respiratory intensive care unit was conducted to determine the diagnostic and therapeutic efficacy of such examinations. Analysis of data from 1,354 x-ray films from 167 patients revealed a 34.5% incidence of new (or increased) abnormali- ties, or tube or catheter malposition. Changes in diagnostic approach or therapeutic measures, excluding catheter posi- tion adjustments, occurred after 28,5% of the examinations. Radiographic yield was higher when a change in clinical condition prompted the radiographic examination than when the examination was a routine morning study. Changes in the approach to patient management were also more likely (42.7%) following examinations that were prompted by a change in a patient's clinical status. Less than 6% of the radiographic films taken postprocedure demonstrated abnor- malities potentially related to the procedure. We conclude that, in a respiratory intensive care unit (1) routine morning radiographic examination frequently demonstrates unex- pected or changing abnormalities, many of which prompt changes in diagnosis or management, (2) radiographic evalu- ation of a change in a patient's clinical condition has higher yield than routine examinations, and (3) postprocedure radiographic examination uncommonly demonstrates com- plications related to the procedure, but frequently demon- strates abnormalities of tube or catheter placement.

Chemotactic Activity in Bronchoalveolar L~vage Fluid From Patients With Adult Respiratory Distress Syndrome. Par- sons pl,: Fowler ,4A. Hyers TM. et el. Am Rev Resplr Dis 132:490, 1985.

Recent studies have shown that an influx of polymorpho- nuclear neutrophils into distal air spaces occurs early in the adult respiratory distress syndrome (ARDS). To study the mechanism of cell accumulation in this syndrome, we have evaluated the chemotactic activity in bronchoalveolar lavage

fluid from patients with ARDS. Lavage fluid was obtained from 16 patients with A RDS within 24 hours of endotracheal intubation and from llve normal nonsmoking subjects. Lay- age fluid from patients with ARDS had art average of 85% neutrophils on differential counts of cytologic preparations compared to less than 3% neutrophils for the control subjects. After removal of cells and lipids, lavage fractions of molecu- lar weight greater than 10,000 daltons were chemotactic for human neutrophils in 14 of 16 patients, but no activity was seen with the normal lavages. Preliminary studies to identify the chemotactie factor were performed.

Aminophylline-lndueed Suppression of Pulmonary Antibac- terial D e f e n s e s . Nelson S, Sumtner WR, and Jakab GJ. Am Rev Respir Dis 131:923, 1985.

Respiratory infections are frequently observed in patients with chronic obstructive pulmonary disease, indicating that host defenses are compromised. Antibacterial defenses of the lung against such infections include the alveolar macrophage and polymorphonuclcar leukocytes (PMN) that migrate into the lung to provide auxiliary phagocytic defenses. To test the hypothesis that aminophylline acutely impairs pulmonary antibacterial defenses, mice were challenged by aerosol inhalation with Staphylococcus aureus or Proteus mirabilis and injected intraperitoneally with aminophylline (20, 40, or 80 mg/kg). Pulmonary bactericidal activity and total lavaged lung cell and differential aminophylline suppressed the kill- ing of S. aureus so that 55 _+ 5% of the initial viable bacteria remained as compared with 22 -+ 4% in the control animals, In contrast, there was a dose-related suppression of pulmo- nary antibacterial defenses against gram-negative bacteria. With doses of 40 and 80 mg/kg, lung defenses were ablated, allowing the proliferation of P. mirabilis to 115 +_ 9% and 253 ± 9%, respectively, the control value being 26 ± 3%. The number of PMN obtained by lavage after aerosol challenge with P. mirabilis was also inhibited by aminophylline in a dose-dependent manner. From the lungs of untreated animals 5.0 _+ 0.3 x 106 PMN were recovered as compared with 3.3 ± 0.1 x 106, 2.5 ± 0.2 × 106, and 1.8 ± 0.1 × 106, respectively, with increasing doses of aminophylline. The bactericidal activity of lavaged PMN from the lungs of aminophylline- treated rats challenged with the gram-negative bacterium in rive was significantly depressed when compared with that in control animals. These studies show that aminophylline sup- presses pulmonary antibacterial defenses by impairing the recruitment and bactericidal capacities of PMN responding to a bacterial challenge, Aminophylline may predispose patients to more frequent and severe infection.

Dissemination of Pseudomones eeruginosa During Lung infection in Hamsters: Role of Qxygen-lnduced Lung Injury. Johanson WG .It. Higuchi JH. Woods DE. et aL Am Rev Respir Dis 132:358, 1985.

Pseudomonas aeruginosa was inoculated into the lungs of normal and oxygen-exposed hamsters. Air-breathing animals developed focal bronchopneumonias, but viable organisms were not recovered from the lungs after three days; baeter- emia was not detected, but P. aerugtnosa was isolated from the livers of three of 12 animals with positive lung cultures. Pseudomonas aeruginosa infections shortened the survival