Multiple flow rates measurement of exhaled nitric oxide in patients with sarcoidosis: a pilot feasibility study.

Fraction of end tidal exhaled nitric oxide (FeNO) has been introduced as a non-invasive marker of airway inflammation in patients with asthma and may have value in monitoring disease activity in patients with sarcoidosis. This pilot study explored: 1) feasibility of the multiple flow rates maneuver to estimate alveolar (C(AlV)NO) and airway wall (J(AW)NO) NO in patients with sarcoidosis; and 2) utility of exhaled NO (FeNO, C(Alv)NO and J(AW)NO) measurements to detect and monitor treatment response in patients with active pulmonary sarcoidosis. Patients with sarcoidosis (n = 42) and healthy non-smokers (n = 20) underwent FeNO measurement at 7 flow-rates (50 to 400 ml/s). Using the Tsoukias and George (1998) model, C(Alv)NO and J(AW)NO were estimated. Both patients and healthy non-smokers were able to perform the multiple flow rates maneuver without discomfort, with first measurement success rate of 57% and 65%, respectively. No significant difference was found between patients with sarcoidosis and healthy non-smokers in exhaled NO. None were correlated with pulmonary function tests, except a significant negative correlation between C(Alv)NO and FVC% (p = 0.001) and DLCO% (p = 0.012). In 8 patients with active sarcoidosis, FeNO, C(Alv)NO or J(AW)NO were not different from those of patients with inactive sarcoidosis. Treatment of active sarcoidosis using oral prednisone and methotrexate did not show any consistent pattern of changes in C(Alv)NO or J(AW)NO. Due to a large inter-subject variability and difficulty controlling use of the inhaled corticosteroids, exhaled NO measurement did not appear to be a clinically useful method of monitoring disease progression in sarcoidosis.

The use of medical emergency teams in medical and surgical patients: impact of patient, nurse and organisational characteristics.

Medical emergency teams (METs) were developed to respond more rapidly to changes in patient condition. While effective, METs do not address events prior to the response. This study examined differences in patient, nurse, and organisational characteristics for 108 MET calls on five medical and five surgical units in a university hospital. MET calls occurred more often on the day shift (p = 0.007) for medical (p = 0.036), but not surgical, patients. Of the 108 events, 44% were delayed, defined as events with documented evidence that pre-established criteria for a MET call were present for >30 min. More delays occurred on the night shift (p = 0.012). Delayed events were not related to the number of patients assigned (p = 0.608). However, there was a trend for more delays when more patients were assigned (4:1 = 21% vs 6:1 = 43%). In a logistic regression model, shift and patient-unit-match (medical, surgical) were significant predictors of delays. The model correctly predicted 68% of delayed events. Study findings indicate that a combination of patient, nurse and organisational characteristics influence timely rescue.

Atrial fibrillation: prevalence after minimally invasive direct and standard coronary artery bypass.

BACKGROUND: This study identified and compared the prevalence of new-onset atrial fibrillation (AFIB) following standard coronary artery bypass grafting (SCABG) with cardiopulmonary bypass (CPB) and minimally invasive direct vision coronary artery bypass grafting (MIDCAB) without CPB. A further comparison was made between AFIB prevalence in SCABG and MIDCAB subjects with two or fewer bypasses. METHODS: This is a retrospective, comparative survey. Patients with new-onset AFIB who underwent SCABG or MIDCAB alone were identified electronically using a triangulated method (International Classification of Diseases, 9th revision, Clinical Modification [ICD-9 CM] code; clinical database word search; and pharmacy database drug search). RESULTS: The total sample (n = 814; 94 MIDCAB, 720 SCABG) exhibited a trend toward lower AFIB prevalence in MIDCAB (23.4%) versus SCABG (33.1%) subjects (p = 0.059). AFIB prevalence in the SCABG subset with two or less vessel bypasses (n = 98; n = 18 single vessel, n = 80 double vessels) and MIDCAB subjects (n = 94; n = 90 single vessels, n = 4 double vessels) was almost identical (SCABG subset 24.5% versus MIDCAB 23.4%, p = 0.860). Slightly more than half (56.9%) of new-onset AFIB subjects were identified by ICD-9 CM codes, with the remainder by word search (37.7%) or procainamide query (5.4%). CONCLUSIONS: In this sample, the number of vessels bypassed seemed to have a greater influence on AFIB prevalence than the application of CPB or the surgical approach. Retrospective identification of AFIB cases by ICD-9 CM code grossly underestimated AFIB prevalence.

Effects of continuous, expiratory, reverse, and bi-directional tracheal gas insufflation in conjunction with a flow relief valve on delivered tidal volume, total positive end-expiratory pressure, and carbon dioxide elimination: a bench study.

INTRODUCTION: Tracheal gas insufflation (TGI) can increase total positive end-expiratory pressure (total-PEEP) when flow is delivered in a forward direction, necessitating adjustments to maintain total-PEEP constant. When TGI is delivered throughout the respiratory cycle, additional adjustments are needed to maintain tidal volume (V(T)) constant. OBJECTIVE: Determine if bi-directional TGI (bi-TGI) (simultaneous flows toward the lungs and upper airway) in combination with a flow relief valve eliminates the increase in total-PEEP and maintains a constant V(T), thus simplifying TGI administration. METHODS: Using an artificial lung model and pressure control ventilation, we studied the effect of TGI at 10 L/min on inspired V(T), total-PEEP, and CO(2) elimination during 6 conditions: (1) control (no TGI, no catheter in the airway), (2) baseline (catheter in the airway but no TGI), (3) continuous TGI, (4) expiratory TGI, (5) reverse TGI, and (6) bi-TGI. Each condition was studied under 3 inspiration-expiration ratios (1:1, 1:2, and 2:1). A preset flow relief valve was inserted into the ventilator circuit during all TGI conditions with continuous flow. SETTING: University research laboratory. RESULTS: CO(2) elimination efficiency was similar under all conditions. Total-PEEP increased with continuous TGI and expiratory TGI, decreased during reverse TGI, and was unchanged during bi-TGI. With the flow relief valve in place, and no adjustment in mechanical ventilation, the change in minute ventilation ranged from 0% to 10%, with the least change during bi-TGI (0-5%). During bi-TGI, gas flow was equivalent in both directions during dynamic conditions and the flow relief valve consistently removed gas at 10 L/min under various pressures. CONCLUSIONS: Our data from an artificial lung model support that continuous bi-TGI minimizes the change in total-PEEP seen during other TGI modalities. The flow relief valve compensated for the extra gas volume delivered by the TGI catheter, thereby eliminating the need to make ventilator adjustments. Used in combination with a flow relief valve, bi-TGI appears to offer unique advantages by providing a simpler method to deliver TGI. Further testing is indicated to determine if similar benefits occur in the clinical setting.

Monitoring and humidification during tracheal gas insufflation.

In order to use tracheal gas insufflation (TGI) in a safe and effective manner, it is important to understand potential interactions between TGI and the mechanical ventilator that may impact upon gas delivery and carbon dioxide (CO2) elimination. Furthermore, potentially serious complications secondary to insufflation of cool, dry gas directly into the airway and the possibility of tube occlusion must be considered during use of this adjunct modality to mechanical ventilation. Regardless of the delivery modality (continuous TGI, expiratory TGI, reverse TGI, or bidirectional TGI), conventional respiratory monitoring is required. However, TGI with mechanical ventilation can alter tidal volume and peak inspiratory pressure and can lead to the development of intrinsic positive end-expiratory pressure. Therefore, depending on the gas delivery technique used, it is important to carefully monitor these ventilatory parameters for TGI-induced changes and understand the potential need for adjustments to ventilator settings to facilitate therapy and avoid problems. Optimally, gas insufflated by the TGI catheter should be conditioned by addition of heat and humidity to prevent mucus plug formation and potential damage to the tracheal mucosa. Finally, patients must be closely monitored for increases in peak inspiratory pressure from obstruction of the tracheal tube and should have the TGI catheter removed and inspected every 8-12 hours to assess for plugs.

Rejection after organ transplantation: a historical review.

Progress toward understanding the biochemical basis of human individuality spans centuries, but tissue rejection remains the primary clinical challenge of organ transplantation. This article highlights the chronology of scientific discoveries made in the quest to overcome the rejection associated with transplantation. The purposes of this review are to raise clinicians' awareness of the advances in surgery, genetics, immunology, and immunosuppression that have contributed to the current knowledge of tissue rejection and to indicate potential new directions in this challenging field.

Auto-positive end-expiratory pressure during tracheal gas insufflation: testing a hypothetical model.

OBJECTIVE: The major benefit of tracheal gas insufflation (TGI) is an increase in CO2 elimination efficiency by removal of CO2 from the anatomical deadspace. In conjunction with mechanical ventilation, TGI may also alter variables that affect CO2 elimination, such as minute ventilation and peak airway pressure (peak Paw) and cause the development of auto-positive end-expiratory pressure (auto-PEEP). We tested the hypothesis that TGI-induced auto-PEEP alters ventilatory variables. We predicted that TGI-induced auto-PEEP offsets the beneficial effects of TGI on CO2 elimination and that keeping total PEEP (ventilator PEEP + auto-PEEP) constant enhances the CO2 elimination efficiency afforded by TGI. DESIGN: Prospective study of two series of patients with acute respiratory distress syndrome receiving mechanical ventilation. SETTING: Intensive care units at a university medical center. PATIENTS: Each series consisted of eight sequential hypercapnic patients. INTERVENTIONS: In series 1, we examined the effect of continuous TGI at 0 and 10 L/min on PaCO2, without compensating for the development of auto-PEEP. In series 2, we examined this same effect of continuous TGI while reducing ventilator PEEP to keep total PEEP constant. TGI-induced auto-PEEP was calculated based on dynamic compliance measurements during zero TGI flow conditions (deltaV/deltaP) after averaging the two baseline values for peak Paw and tidal volume and assuming compliance did not change between the zero TGI and TGI flow conditions (deltaVTGI/deltaPTGI). MEASUREMENTS AND MAIN RESULTS: In series 1, total PEEP increased from 13.2 +/- 3.2 cm H2O to 17.8 +/- 3.5 cm H2O without compensation for auto-PEEP (p = .01). PaCO2 decreased (p = .03) from 56.2 +/- 10.6 mm Hg (zero TGI) to 52.9 +/- 9.3 mm Hg (TGI at 10 L/min), a 6% decrement. In series 2, total PEEP was unchanged (p = NS). PaCO2 decreased (p = .03) from 59.5 +/- 10.4 mm Hg (zero TGI) to 52.2 +/- 8.3 mm Hg (TGI at 10 L/min), a 12% decrement. There was no significant change in PaO2; there were no untoward hemodynamic effects in either series. CONCLUSIONS: These data are consistent with the hypothesis that mechanical ventilation + TGI causes an increase in auto-PEEP that can blunt CO2 elimination. In addition to the ventilator modifications necessary to keep ventilatory variables constant when TGI is used, it is also necessary to reduce ventilator PEEP to keep total PEEP constant and further enhance CO2 elimination efficiency.

Tracheal gas insufflation. Limits of efficacy in adults with acute respiratory distress syndrome.

In mechanically ventilated adults with acute respiratory distress syndrome (ARDS), peak airway pressures (Paw(peak)) above 35 cm H(2)O may increase the risk of barotrauma or volutrauma. Tracheal gas insufflation (TGI), an adjunctive ventilatory technique, may facilitate a reduction in set inspiratory pressure in these patients, and thereby in the tidal volume (VT) and Paw(peak) used in their ventilation, without a consequent increase in arterial carbon dioxide tension (PaCO(2)). The purpose of this study was to: (1) assess the limits of efficacy of continuous TGI at two levels of decreased mechanical ventilatory support; and (2) determine an appropriate time interval after initiation of TGI at which to evaluate response. We prospectively studied eight adults with ARDS and increased airway pressures (40.2 +/- 2.7 cm H(2)O) who were managed with pressure-control ventilation (PCV). After obtaining baseline ventilatory and hemodynamic measures, we initiated TGI at 10 L/min, adjusting ventilator positive-end expiratory pressure (PEEP) to maintain baseline VT, and decreased the set inspiratory pressure by 5 cm H(2)O. Data were obtained after 30 and 60 min. Set inspiratory pressure was then decreased by an additional 5 cm H(2)O (total: 10 cm H(2)O), and data were again obtained after 30 min. Baseline (zero TGI) measures were then again recorded. Thirty minutes after decreasing the set inspiratory pressure by 5 cm H(2)O with TGI at 10 L/min, there was a 15% decrease in Paw(peak) and a 16% decrease in VT as compared with their baseline values. However, Pa(CO(2)) remained constant (59 +/- 10 mm Hg versus 57 +/- 6 mm Hg) (p = NS). There was no change in Pa(O(2)) or in hemodynamic variables, and no differences between variables, at 30 min versus 60 min in seven subjects. The remaining subject did not tolerate the reduction in set inspiratory pressure for 60 min. Thirty minutes after the set inspiratory pressure was decreased by 10 cm H(2)O with TGI at 10 L/min, there was a 26% decrease in Paw(peak) and a 26% decrease in VT. However, Pa(CO(2)) increased by 19% and Pa(O(2)) decreased by 13%. Six subjects completed this phase of the protocol for 30 min, and one subject completed it for 60 min. TGI can be used to rapidly facilitate a 5 cm H(2)O reduction in set inspiratory pressure without an increase in Pa(CO(2)). The ability to achieve a 5 cm H(2)O reduction in set inspiratory pressure without adverse physiologic effects was evident within 30 min. Attempts to further reduce set inspiratory pressure were not successful.

Large-volume liposuction complicated by retroperitoneal hemorrhage: management principles and implications for the quality improvement process.

Large-volume liposuction can be associated rarely with major medical complications and death. The case of exsanguinating retroperitoneal hemorrhage that led to cardiopulmonary arrest in an obese 47-year-old woman who underwent large-volume liposuction is described. Extensive liposuction is not a minor procedure. Performance in an ambulatory setting should be monitored carefully, if it is performed at all. Reporting of adverse events associated with outpatient procedures performed by plastic surgeons should be mandated. Hemodynamic instability in the early postoperative period in an otherwise healthy patient may be due to fluid overload, lidocaine toxicity, or to hemorrhagic shock and must be recognized and treated aggressively. Guidelines for the safe practice of large-volume liposuction need to be established.

Digital replantation teaching model in rats.

Replant surgery is a complex procedure that requires advanced microsurgical skills and is usually performed as an emergency operation, lasting many hours. For these reasons, teaching replantation is difficult. Although teaching models exist, they are often too general or complicated for routine use and do not simulate the stages and the pitfalls of human replant surgery. We have designed a model that is simple and imitates human replant surgery. After reviewing the rat anatomy, students dissect and replant a rat hind limb that has been sharply amputated by the instructor. They follow the same principles of "real" surgery like debridement, minimizing ischemia time, and stable fixation before anatomosis of vessels. After marking the structures, bony fixation followed by vessel and nerve anastomosis are performed. Muscle is reattached to the skin and limb vascularity evaluated. After we designed this model, plastic surgery residents performed the technique on 10 rats. An 80% limb viability rate was achieved. This model is simple to perform, simulates all the relevant structures and pitfalls of human surgery, and the rats are relatively cheap and can be used for other parallel projects.

Generation or large numbers of immature and mature dendritic cells from rat bone marrow cultures.

We have defined conditions for generating large numbers of dendritic cells (DC) in marrow cultures from 10-12-week-old ACI or WF rats. The combination of granulocyte-macrophage colony-stimulating factor (GM-CSF) and TNF-alpha, known to induce DC from human CD34+ progenitors, was not effective with rat. In contrast, GM-CSF plus IL-4 generated DC in high yield, corresponding to 30-40% of the initial number of plated marrow cells. The DC proliferated in distinctive aggregates, in which most cells had an immature phenotype marked by undetectable surface B7 and high levels of MHC class II products within intracellular lysosomes. When dislodged and dispersed, the aggregates gave rise to mature stellate DC with abundant surface MHC class II and B7, sparse MHC class II- lysosomes, and strong T cell-stimulating capacity. Therefore, rat marrow progenitors can generate large numbers of immature DC, with abundant intracellular MHC class II compartments, and potent, stimulatory, mature DC.

Clinical features and outcome of patients admitted to the intensive care unit after plastic surgical procedures: implications for cost reduction and quality of care.

Recent interest in cutting cost and improving utilization and delivery of perioperative services has prompted surgeons to identify patient populations that would benefit from care in an intensive care unit as opposed to intermediate or standard care. The purpose of this study was to evaluate patients admitted to the surgical intensive care unit (SICU) after major plastic/reconstructive surgical procedures in order to determine appropriate perioperative management strategies for these patients. We reviewed retrospectively the data from 2,805 consecutive admissions to the SICU between 1990 and 1996. Forty-two patients (1.5%) who had undergone major plastic/reconstructive procedures were identified. Outcomes (mortality, length of stay in the SICU and hospital, and the degree of organ dysfunction) were compared between this population, an illness severity-matched (Acute Physiology and Chronic Health Evaluation [APACHE]-II and APACHE III) population of patients recovering from vascular surgical procedures, and a similarly matched population of SICU patients who were randomly assigned to serve as a second control group. The hospital mortality of the plastic surgical patient population (9.5%) was significantly higher than the zero mortality of the random cohort (p < 0.05). A second analysis compared the SICU plastics group to a case-controlled group of patients who were admitted to the postanesthesia care unit (PACU) for at least 24 hours of perioperative monitoring. SICU patients had significantly higher APACHE II scores (10.9) when compared to PACU patients (7.2; p < 0.01). Based on severity of illness scoring and eventual mortality, patients admitted to our SICU after major reconstructive surgery were selected appropriately for that setting. In contrast, the patients who stayed in the PACU for perioperative monitoring did not require life-supporting therapy and, therefore, were overmonitored. Care could be provided in a specialized unit with dedicated nursing specifically trained for that purpose.

Ischemia-reperfusion injury in myocutaneous flaps: role of leukocytes and leukotrienes.

Leukotriene B4 is a potent inflammatory mediator that is derived from the 5-lipoxygenase pathway of arachidonic acid metabolism and that has been implicated in the pathophysiology of polymorphonuclear leukocyte-dependent reperfusion injury in a variety of organ systems. The objectives of these investigations were to determine whether inhibition of leukotriene B4 attenuates postischemic polymorphonuclear leukocyte infiltration and subsequent injury in myocutaneous flaps. Anesthetized female Yorkshire pigs were randomized to receive normal saline (n = 8), the 5-lipoxygenase inhibitor diethylcarbamazine (n = 7), or the leukotriene B4 receptor antagonist SC-41930 (n = 7). All animals underwent 6 hours of rectus abdominis myocutaneous flap ischemia followed by 4 hours of reperfusion. In saline-treated controls, flap ischemia was associated with massive polymorphonuclear leukocyte infiltration at 1 and 4 hours of reperfusion (252 +/- 70 and 619 +/- 137 polymorphonuclear leukocytes per 25 high-power fields, respectively). Skeletal muscle neutrophil content was significantly attenuated by pretreatment with diethylcarbamazine (72 +/- 29 and 229 +/- 63 polymorphonuclear leukocytes per 25 high-power fields; p < 0.05) or SC-41930 (25 +/- 3 and 193 +/- 25 polymorphonuclear leukocytes per 25 high-power fields; p < 0.05). Wet-to-dry weight ratios of full-thickness flap biopsies were lower in the diethylcarbamazine and SC-41930 groups (2.98 +/- 0.15 and 2.90 +/- 0.26, respectively) than in the control group (4.13 +/- 0.23; p < 0.01), and mean muscle infarct size, as determined by nitroblue tetrazolium staining, diminished from 47.6 +/- 11.3 percent in controls to 25.1 +/- 6.5 percent in diethylcarbamazine-treated animals and 7.3 +/- 4.8 percent in SC41930-treated animals (p < 0.05). These data indicate that leukotriene B4 plays a critical role in mediating neutrophil-dependent injury in postischemic skeletal muscle flaps.

Tracheal gas insufflation improves ventilatory efficiency during metacholine-induced bronchospasm.

INTRODUCTION: Barotrauma and cardiovascular insufficiency are frequently encountered problems in patients with acute bronchospastic disease who require mechanical ventilation. Permissive hypercapnia is a recognized strategy for minimizing these adverse effects; however, it has potential risks. Tracheal gas insufflation (TGI) has been shown to increase carbon dioxide elimination efficiency and thus could permit mechanical ventilation at lower peak airway pressures without inducing hypercapnia. However, caution exists as to the impact of TGI on lung volumes, given that expiratory flow limitation is a hallmark of bronchospastic disease. PURPOSE: To examine these issues, we studied ventilatory and hemodynamic effects of continuous TGI as an adjunct to mechanical ventilation before and after methacholine-induced bronchospasm. MATERIALS AND METHODS: Ten anesthetized, paralyzed dogs were ventilated on volume-controlled mechanical ventilation during administration of continuous TGI (0, 2, 6, and 10 L/min) while total inspired minute ventilation (ventilator-derived minute ventilation plus TGI) was kept constant. In an additional step, with TGI flow of 10 L/min, total inspired minute ventilation was decreased by 30%. RESULTS: PaCO2 decreased (44 +/- 7 mm Hg at zero flow to 34 +/- 7 mm Hg at 6 L/min and 31 +/- 6 mm Hg at 10 L/min, respectively, P < .05), as did the dead space to tidal volume ratio at TGI of 6 and 10 L/min compared with zero flow. There were no significant changes in end-expiratory transpulmonary pressure, mean arterial pressure, or cardiac output. During the highest TGI flow (10 L/min), with a 30% reduction of total inspired minute ventilation, both PaCO2 and peak airway pressure remained less than during zero flow conditions. CONCLUSION: We conclude that TGI increases carbon dioxide elimination efficiency during constant and decreased minute ventilation conditions without any evidence of hyperinflation or hemodynamic instability during methacholine-induced bronchospasm.

Intestinal perforation after suction lipoplasty: a case report and review of the literature.

Intrabdominal penetration with intestinal perforation is a relatively uncommon complication after liposuction. Seven cases have been reported in the literature, with a mortality rate > 50%. Here we present a case of a perforated viscus after suction lipoplasty of the abdomen using the tumescent technique. Multiple small-bowel enterotomies were made with the suction cannula. It is our hope that a heightened awareness of this potentially life-threatening complication will promote early and aggressive diagnosis and treatment of liposuction patients who present with gastrointestinal complaints in the early postoperative period.

Tracheal gas insufflation during pressure-control ventilation: effect of using a pressure relief valve.

OBJECTIVES: Pressure-control ventilation minimizes alveolar overdistention by limiting peak airway pressure, but a consequence of this pressure limitation may be a reduction in tidal volume with subsequent hypercarbia. Tracheal gas insufflation (TGI) can be used in combination with pressure-control ventilation to augment CO2 elimination. During pressure-control ventilation with continuous TGI, we observed that peak airway pressure increased above the set inspiratory pressure. Based on this observation, we investigated the ability of the pressure-control ventilator circuit to compensate for continuous TGI and the effect of insertion of a pressure relief valve to eliminate over-pressurization. SETTING: University research laboratory. DESIGN: Using an artificial lung model, we studied the effects of continuous TGI with varying catheter flows (0, 2, 6, and 10 L/ min); ventilator frequencies (10 and 20 breaths/min); inspiratory duty cycles (0.33, 0.50, and 0.67); lung compliance (0.01, 0.02, and 0.04 L/cm H2O); and airway resistance (5, 20, and 50 cm H2O/L/sec) on: a) peak airway pressure; b) total inspiratory tidal volume; c) ventilator-derived tidal volume; and d) intrapulmonary pressure at end-exhalation (auto-PEEP). Tests were performed with and without a pressure relief valve whose threshold "pop-off" pressure was adjusted to match the set inspiratory pressure (35 cm H2O) for a total of 432 experimental conditions. MEASUREMENTS AND MAIN RESULTS: Our data demonstrate that pressure-control ventilation augmented with continuous TGI can increase peak airway pressure above set inspiratory pressure due to delivery of a higher than intended tidal volume. Predisposing conditions include catheter flow rates of 6 and 10 L/min, long inspiratory time, low compliance, and low resistance. With the pressure relief valve, peak airway pressure was maintained at the set inspiratory pressure and total inspiratory tidal volume remained constant. CONCLUSION: A pressure relief valve is a necessary adjunct to maintain peak airway pressure at set inspiratory pressure and keep total inspiratory tidal volume constant when continuous TGI is administered in conjunction with pressure-control ventilation.

Modification of macrophage adhesion by ozone: role of cytokines and cell adhesion molecules.

The inflammatory response in the lungs following an inhalation exposure of animals and humans to ozone (O3) is associated with macrophage stimulation, release of chemotactic agents, and neutrophilia. This study investigated the adhesive behavior of the alveolar macrophages and its relevance to the inflammatory processes in the lung. Macrophages recovered by BAL from rats exposed to purified air or 0.8 ppm O3 were studied in vitro for their adhesion to epithelial cells derived from ARL-14. The macrophages from O3-exposed animals displayed greater adhesion to the epithelial cells than the macrophages from control rats exposed to purified air. The O3-induced adhesion was attenuated in the macrophages treated with a combination of interleukin-1 alpha and tumor necrosis factor-alpha antibodies (anti-IL-1+anti-TNF). The cell adhesion stimulated by O3 exposure was also attenuated when the macrophages were incubated in the presence of antibodies to leukocyte adhesion molecules, CD11b, or epithelial cell adhesion molecules, ICAM-1. A marginal increase in the surface expression of CD11b was noticed in macrophages from the rats exposed to O3. A similar change in the ICAM-1 expression was, however, not observed. The results suggest that the O3-induced modifications of macrophages are mediated by IL-1 and TNF, and that these modifications are accompanied by a minimal change in the expression of the cell-adhesion molecules.