A new look at old agents for pleurodesis: nitrogen mustard, sodium hydroxide, and silver nitrate

In this review we analyze the evolution of pleurodesis. In spite of the fact that this procedure started in the beginning of the 20th century, the ideal sclerosing agent is not yet known. Emphasis is placed on the current tendency toward minimally invasive procedures in which insertion of catheters is favored over surgical procedures such as placement of chest tubes or thoracoscopy. Among the sclerosing agents, talc is preferred throughout the world. However, the possible development of acute respiratory distress syndrome, which is sometimes fatal, caused the awakening of interest in other drugs. Nitrogen mustard induces pleurodesis but causes important side effects. Sodium hydroxide and silver nitrate are effective and may be used in humans beings.

Antibiotic levels in empyemic pleural fluid

OBJECTIVE

To determine the degree to which bioactive penicillin, metronidazole, ceftriaxone, clindamycin, vancomycin, and gentamicin penetrate into empyemic pleural fluid using our new rabbit model of empyema.

METHODS

An empyema was created via the intrapleural injection of 10(8)()Pasteurella multocida bacteria into the pleural space of New Zealand white rabbits. After an empyema was verified by thoracentesis and pleural fluid analysis, penicillin, 24,000 U/kg; metronidazole, 37 mg/kg; ceftriaxone, 30 mg/kg; clindamycin, 9 mg/kg; vancomycin, 15 mg/kg; or gentamicin, 1 mg/kg, were administered IV. Antibiotic levels in samples of pleural fluid and serum, collected serially for up to 480 min, were then determined using a bioassay.

RESULTS

The degree to which the different antibiotics penetrated into the infected pleural space was highly variable. Penicillin penetrated most easily, followed by metronidazole, ceftriaxone, clindamycin, vancomycin, and gentamicin. Of the antibiotics tested, penicillin and metronidazole equilibrated the most rapidly with the infected pleural fluid. Penicillin levels remained elevated in pleural fluid even after serum levels had decreased.

CONCLUSIONS

Using this rabbit model of empyema, there was marked variation in the penetration of antibiotics into the empyemic fluid. Although there are species differences between rabbit and human pleura, the variance in degree of penetration of antibiotics into the pleural space should be considered when antibiotics are selected for the treatment of patients with empyema.

The utility of daily therapeutic thoracentesis for the treatment of early empyema

STUDY OBJECTIVES

To determine if therapeutic thoracentesis is as effective as early chest tube placement or no drainage procedure in the treatment of early empyema in rabbits.

DESIGN AND INTERVENTIONS

An empyema, as evidenced by gross pleural pus and a decreased pleural fluid pH and glucose level, was induced in 49 rabbits. The rabbits were divided into three groups: 16 underwent daily therapeutic thoracentesis starting at 48 h, 14 underwent chest tube placement at 48 h, and 19 served as controls.

RESULTS

The mortality rate in the therapeutic thoracentesis group (0/16) did not differ significantly from that in the chest tube group (3/14) or that in the control group (6/19). At autopsy at 10 days, the gross empyema score in the therapeutic thoracentesis group (2.1 +/- 0.3) was significantly lower (p < 0.05) than that in the chest tube group (2. 8 +/- 0.3) or the control group (3.5 +/- 0.2). The mean pleural peel score of 5.8 +/- 1.1 in the therapeutic thoracentesis group was significantly less (p < 0.05) than the score for the nonintervention control group (13.4 +/- 1.6).

CONCLUSIONS

From this study, we conclude that therapeutic thoracentesis is at least as effective as early chest tube placement for the treatment of early empyema using our rabbit model of empyema.

Effectiveness of silver nitrate compared to talc slurry as pleural sclerosing agent in rabbits. Influence of concomitant intrapleural lidocaine

The ideal agent for producing pleurodesis has not been identified. Talc, the most commonly used, poses several problems. Another possibility is silver nitrate, which was widely used in the past.

PURPOSE

To determine the influence of the intrapleural instillation of lidocaine in producing a pleurodesis with silver nitrate, to define the effect of lidocaine in the maturation of the collagen fibers, and to confirm that the pleurodesis after silver nitrate is stronger than after talc.

METHODS

We studied three groups of 8 rabbits. Two groups received 0.5% silver nitrate; in one we had previously injected 0.5 ml of 2% lidocaine. The third group received 400 mg/kg talc (2 ml). The animals were sacrificed 28 days after the injection, and the pleural spaces were assessed grossly for evidence of pleurodesis and microscopically for evidence of inflammation and fibrosis. The total amount of pleural collagen and the distribution of thick and thin collagen fibers were quantified. Collagen was identified using picrosirius red stain.

RESULTS

In the two groups that received silver nitrate (without lidocaine: 3.5 + 03 and with lidocaine: 3.2 + 0.3), the macroscopic pleurodesis (scale 0 - 4) was significantly (p = 0.001) better than that resulting from talc (1.6 + 0.2). The mean degree of pleural fibrosis induced by silver nitrate (3.5 + 0.2) was significantly (p = 0.004) higher than that induced by talc (1.9 + 0.1). The previous instillation of lidocaine resulted in a tendency for decreased amounts of fibrosis (3.1 + 0.4). The mean amount (10(3)mm2) of pleural collagen was significantly (p = 0.009) greater in the rabbits that received silver nitrate (116.9 + 22.7) than in those that received talc (10.7 + 3.4). The injection of lidocaine slightly reduced the collagen (80.1 + 30.3). The distribution of collagen fibers did not differ among the groups.

CONCLUSION

This rabbit model clearly confirms that intrapleural silver nitrate is more effective than talc for producing pleurodesis. The previous intrapleural instillation of lidocaine results in a decreasing trend in the amount of collagen, but does not change the effectiveness of the pleural fusion or modify the process of collagen maturation.

Effect of pneumothorax on pleurodesis induced with talc in rabbits

OBJECTIVE

The purpose of this study was to determine if a small pneumothorax would influence the pleurodesis resulting from talc instillation.

METHODS

Sixty rabbits received an intrapleural injection of 400 mg/kg talc slurry. One half also received 10 mL of air intrapleurally after the talc. Ten rabbits in each group were killed 2, 14, and 28 days after instillation.

RESULTS

Two days after the injection, the mean volume of air in the animals that had received the air was 7.5+/-0.4 mL. There was no air present in any other rabbits. The volume of pleural fluid and the pleural fluid glucose, protein, cell count, and differential were similar in both groups on day 2, while the LDH level was significantly higher in the air group (p<0.05). The degree of gross adhesions and microscopic fibrosis was similar in both groups and increased with time.

CONCLUSIONS

A small pneumothorax does not decrease the efficacy of talc pleurodesis in our experimental model. These results suggest that the presence of a small amount of intrapleural air is not a contraindication to talc pleurodesis in humans.

Serial observations after high dose talc slurry in the rabbit model for pleurodesis

The mechanisms leading to a pleurodesis after the intrapleural injection of a sclerosing agent are not completely understood. The purpose of the present study was to make serial observations over 28 days on the pleural fluid findings and the gross and microscopic changes in the pleura after talc slurry administered intrapleurally at a high dose. Sixty-six rabbits received 400 mg/kg talc slurry. Ten to 12 rabbits were sacrificed 1, 2, 4, 7, 14, and 28 days after the intrapleural injection. At sacrifice the pleural fluid was measured and analyzed, and the pleural surfaces were studied grossly and microscopically. The intrapleural injection of 400 mg/kg talc slurry resulted in an acute exudative pleural effusion that persisted for 4 days. There was a progressive increase in the gross and microscopic fibrosis over the 28 days. Talc was present at the time of sacrifice in all animals. At 28 days there was a clinically significant pleurodesis in all rabbits; pleurodesis was not observed before this time. From this study we conclude that the intrapleural injection of 400 mg/kg talc slurry leads to an acute exudative pleural effusion and clinically significant pleurodesis that is present on day 28 but not day 14. It appears that the production of a pleurodesis requires higher doses of talc in rabbits without a chest tube than in humans with a chest tube.

Doxycycline pleurodesis in rabbits: comparison of results with and without chest tube

We have reported previously that there is a high incidence of hemothorax and substantial mortality in rabbits that are given tetracycline derivatives intrapleurally. However, such complications have not been reported in humans when pleurodesis is attempted with tetracycline derivatives. One primary difference in the two situations is that a chest tube is placed only in humans. The objective of this study was to evaluate the hypothesis that chest tube placement would prevent the development of hemothoraces and lead to better pleurodesis in rabbits given doxycycline intrapleurally. Eighty New Zealand White male rabbits received doxycycline, 20 mg/kg, in a total volume of 2 mL. One half of the rabbits were randomized to receive a chest tube at the time of the injection and were subjected to pleural fluid aspiration twice daily. The remaining rabbits (control group) received no chest tube and no aspiration. Ten rabbits from each group were killed on days 4, 7, 14, and 28. The intrapleural injection of doxycycline induced the production of large exudative effusions. The insertion of chest tubes prevented the development of hemothorax (0/20 in chest tube group, 15/20 in control group, p<0.001). The insertion of chest tubes was also associated with a significant reduction in mortality and a significant improvement in pleurodesis. When pleurodesis is attempted in rabbits with intrapleural doxycycline, the insertion of a chest tube will prevent hemothorax and lead to a better pleurodesis.

Antibiotic treatment of patients with pneumonia and pleural effusion

Despite all medical advances of this century, pneumonia is still a common condition and the sixth leading cause of mortality in the United States. A pleural effusion develops in up to 40% of cases of pneumonia and empyema in 5% to 10% of those patients. The morbidity and mortality rates in patients with pleural effusions as a consequence of pneumonia are higher than in patients with pneumonia alone. In this review we discuss the classification, bacteriology, and the appropriate antibiotic treatment of patients with parapneumonic pleural effusions.

Acute and chronic pleural changes after the intrapleural instillation of mitoxantrone in rabbits

A previous study demonstrated that the intrapleural injection of 2 mg/kg mitoxantrone in rabbits resulted in a degree of pleurodesis which is comparable to that seen after 35 mg/kg tetracycline but that the animals had a high mortality rate after this dose of mitoxantrone. The objective of the present study was to assess the acute pleural fluid findings, the acute gross and microscopic pleural findings, and the chronic gross and microscopic findings in rabbits that received mitoxantrone. Mitoxantrone, 1.5 mg/kg, was instilled intrapleurally in 70 lightly anesthetized male rabbits. Groups of rabbits were sacrificed 1, 2, 4, 7, 15, 28, and 60 days after the injection. The intrapleural injection of mitoxantrone resulted in an exudative effusion on day 1. The pleural fluid contained predominantly neutrophils and had a mean lactate dehydrogenase (LDH) level that exceeded 4,000 IU/liter. Over the following week the volume of fluid diminished, the predominant cell became the macrophage, and the LDH levels decreased to less than 400 IU/liter. Macroscopic examination of the pleural space revealed that the mean degree of pleurodesis increased progressively over the 60-day observation period. With microscopy, the mean degree of pleural fibrosis also increased progressively. There were also substantial fibrosis and inflammation of the underlying lung and the contralateral lung. The mortality rates were low in the first 28 days (3/70) but subsequently increased and exceeded 80% in the period between 60 and 120 days. This experimental model of pleurodesis should be useful in future studies directed toward uncovering the mechanisms of pleurodesis.

Systemic corticosteroids decrease the effectiveness of talc pleurodesis

Corticosteroids can inhibit the inflammatory process and the formation of fibrosis. The purpose of this study was to determine whether the concurrent use of steroids at the time of talc-slurry pleurodesis would influence the development of the pleurodesis. One group of rabbits received an intrapleural injection of talc (400 mg/kg) and an intramuscular injection of triamcinolone (0.8 mg/kg) 1 d before talc instillation and weekly thereafter, whereas a control group received only talc. Ten rabbits in each group were killed at 6 h and at 1, 2, 4, 7, 14, and 28 d after instillation. The mean volume of pleural fluid was significantly lower in the group receiving corticosteroids at 6 h through 4 d after talc slurry than in the other groups. The degree of pleural adhesion was significantly smaller in the group receiving corticosteroids from Day 2 through Day 28. At Day 28, all 10 rabbits that received talc only had a pleurodesis score of 3 or 4, whereas only four of the 10 rabbits that also received steroids had a pleurodesis score of 3 or 4. This study shows that the use of corticosteroids at the time of talc-slurry pleurodesis markedly decreases the inflammatory reaction to the talc, and essentially prevents a pleurodesis from developing.

Pulmonary function after coronary artery bypass surgery

Coronary artery bypass graft surgery (CABG) adversely affects pulmonary function tests (PFTs). Although several previous studies have addressed these changes, none has measured the forced vital capacity (FVC) on a daily basis. The purpose of the present study was to assess serial changes in the FVC following CABG and to identify factors that may influence these changes. The FVC was obtained pre- and daily postoperatively (1-10 days) in 120 patients. Fifty-one patients received saphenous vein grafts (SVG group) while 69 received at least one internal mammary artery graft in addition to SVG (IMA group). On the first postoperative day, the FVC decreased to 33% of the pre-operative value in the SVG group and to 29% in the IMA group. The spirometry gradually improved, but after 10 days, the FVC remained reduced (SVG, 70%; IMA, 60%). Although the decreases in FVC tended to be greater in the IMA group, there was no significant difference in the two groups (P = 0.27). The changes in FVC were not significantly related to age (P = 0.48), smoking history (P = 0.65), anesthesia (P = 0.38) or pump time (0.09). From this study, it is concluded that after CABG, there is a significant worsening of the pulmonary function. The nadir of FVC occurs immediately after surgery and improves gradually thereafter. However, on the tenth postoperative day, the FVC still remains more than 30% below pre-operative values. Since there is only a slight tendency for patients undergoing IMA grafting to have larger decreases in their pulmonary function, patients with ventilatory impairment should not be excluded from IMA grafting.

Comparison of nitrogen mustard, cytarabine and dacarbazine as pleural sclerosing agents in rabbits

We have previously shown that the intrapleural injection of mitozantrone but not bleomycin resulted in pleural fibrosis. Mechlorethamine hydrochloride (nitrogen mustard) was used extensively in the past to control malignant effusions, with relatively good success. The objective of this study was to determine if the intrapleural injection of nitrogen mustard would produce pleural sclerosis in our experimental model in rabbits. We therefore evaluated sclerosing capabilities of nitrogen mustard as well as those of cytarabine and dacarbazine. Nitrogen mustard (0.4 and 0.8 mg x kg(-1)), cytarabine (3, 6 and 20 mg x kg(-1)) and dacarbazine (4, 8 and 20 mg x kg(-1)) were instilled intrapleurally into anaesthetized rabbits. Twenty eight days after the instillation, the animals were killed, and the pleural spaces were assessed grossly for evidence of pleurodesis and microscopically for evidence of fibrosis and inflammation. The intrapleural injection of 0.8 mg x kg(-1) nitrogen mustard was effective in creating pleural fibrosis, either grossly or microscopically. The mean degree (scale 0-4) of gross pleurodesis in the rabbits that received 0.8 mg x kg(-1) nitrogen mustard was 3.2+/-1.0 and the mean degree of microscopic pleural fibrosis was 3.5+/-0.8. The intrapleural injection of 0.4 mg x kg(-1) nitrogen mustard and the different doses of cytarabine (3, 6 and 20 mg x kg(-1)) and dacarbazine (4, 8 and 20 mg x kg(-1)) were ineffective in producing pleurodesis. From this study, we conclude that the intrapleural injection of 0.8 mg x kg(-1) of nitrogen mustard produces clinically significant pleurodesis in rabbits. Consideration should be given to future clinical studies utilizing 0.6-0.8 mg x kg(-1) nitrogen mustard intrapleurally for the treatment of malignant pleural effusion.

Comparison of nitrogen mustard, cytarabine and dacarbazine as pleural sclerosing agents in rabbits

We have previously shown that the intrapleural injection of mitozantrone but not bleomycin resulted in pleural fibrosis. Mechlorethamine hydrochloride (nitrogen mustard) was used extensively in the past to control malignant effusions, with relatively good success. The objective of this study was to determine if the intrapleural injection of nitrogen mustard would produce pleural sclerosis in our experimental model in rabbits. We therefore evaluated sclerosing capabilities of nitrogen mustard as well as those of cytarabine and dacarbazine. Nitrogen mustard (0.4 and 0.8 mg x kg(-1)), cytarabine (3, 6 and 20 mg x kg(-1)) and dacarbazine (4, 8 and 20 mg x kg(-1)) were instilled intrapleurally into anaesthetized rabbits. Twenty eight days after the instillation, the animals were killed, and the pleural spaces were assessed grossly for evidence of pleurodesis and microscopically for evidence of fibrosis and inflammation. The intrapleural injection of 0.8 mg x kg(-1) nitrogen mustard was effective in creating pleural fibrosis, either grossly or microscopically. The mean degree (scale 0-4) of gross pleurodesis in the rabbits that received 0.8 mg x kg(-1) nitrogen mustard was 3.2+/-1.0 and the mean degree of microscopic pleural fibrosis was 3.5+/-0.8. The intrapleural injection of 0.4 mg x kg(-1) nitrogen mustard and the different doses of cytarabine (3, 6 and 20 mg x kg(-1)) and dacarbazine (4, 8 and 20 mg x kg(-1)) were ineffective in producing pleurodesis. From this study, we conclude that the intrapleural injection of 0.8 mg x kg(-1) of nitrogen mustard produces clinically significant pleurodesis in rabbits. Consideration should be given to future clinical studies utilizing 0.6-0.8 mg x kg(-1) nitrogen mustard intrapleurally for the treatment of malignant pleural effusion.

Gallium-67 lung imaging and pulmonary clearance of 99mTc-DTPA aerosol in patients with amiodarone pneumonitis

The aim of this study was to compare gallium-67 citrate lung imaging with the pulmonary clearance of 99mTc-DTPA (technetium 99m diethylenetriaminepentaacetic acid) in 9 patients with amiodarone pneumonitis (8 males and 1 female, aged 58 to 76 years). The diagnosis of amiodarone pneumonitis was based on clinical and radiological grounds in all patients, and histological changes in seven. The mean values for the effective half-life of the pulmonary clearance of 99mTc-DTPA aerosol were below the normal range in all 9 patients, and lower than the values obtained previously for patients on a long-term amiodarone regimen without side effects. Positive gallium-67 accumulation was demonstrated in 7 of the 9 patients. Two patients had negative gallium-67 imaging and increased alveolar-capillary 99mTc-DTPA clearance; with corticosteroid therapy and discontinuation of amiodarone, their radiological changes and clearance became normal within 120 days. In conclusion, when compared to gallium-67 lung imaging, the 99mTc-DTPA aerosol clearance is more advantageous because it is a much faster test than the gallium scan. This is essential for those patients suspected of amiodarone pneumonitis who need specific therapy as soon as possible. Moreover, the 99mTc-DTPA aerosol clearance test appears to be a more useful diagnostic tool because it is positive even in those patients who have normal gallium-67 lung imaging.

Effectiveness of sodium hydroxide as a pleural sclerosing agent in rabbits: influence of concomitant intrapleural lidocaine

The two agents that have been used most commonly to produce a pleurodesis are tetracycline and bleomycin. Tetracycline is no longer generally available because of more stringent requirements on the manufacturing process. Bleomycin is very expensive. Therefore, alternative agents are necessary particularly in developing countries. The objective of this project was to determine whether 0.5% sodium hydroxide is an effective sclerosant in an experimental model in rabbits. Sodium hydroxide (NaOH) (2 ml of 0.5%) was instilled intrapleurally in 24 anesthetized male rabbits. Half the rabbits received 1 ml of 2% lidocaine 3-5 min before the NaOH. Twenty-eight days after the instillation, the animals were sacrificed, and the pleural spaces were assessed grossly for evidence of pleurodesis and microscopically for evidence of fibrosis and inflammation. The results indicated that the intrapleural injection of NaOH was effective in creating a pleurodesis only if the animals were not premedicated with lidocaine. The mean (+/- S.D.) degree of gross pleurodesis after NaOH alone 2.8 (1.0) was significantly (p < 0.001) greater than after that following the combination 1.3 (0.5). We conclude that NaOH is an effective pleural sclerosant but that it is ineffective if it is injected concomitantly with lidocaine.

Pleural malignancies

Carcinoma of the lung, metastatic breast carcinoma, and lymphoma are responsible for approximately 75% of all malignant pleural effusions. The presence of malignant cells in the pleural fluid or in the parietal pleura confirms the diagnosis. Recently, several authors have proposed the combination of morphometric procedures and quantitative analysis of nucleolar organizer regions stained by silver nitrate. Videothoracoscopy is recommended for patients suspected of having a malignant pleural effusion in whom the diagnosis is not established after two cytologic studies of the fluid and one needle biopsy. The standard treatment is the intrapleural instillation of a chemical agent to produce a pleurodesis. The recommended sclerosant is talc, a tetracycline derivative, or Corynebacterium parvum where it is available. When a patient is not an ideal candidate for chemical pleurodesis, the options include symptomatic treatment, serial thoracentesis, implantation of a pleuroperitoneal shunt, and pleurectomy.

Corynebacterium parvum versus tetracycline as pleural sclerosing agents in rabbits

Tetracycline has been one of the most commonly used agents for producing a pleurodesis. However, it is no longer available due to more stringent requirements on the manufacturing process. The objective of this project was to determine whether Corynebacterium parvum is an effective sclerosant in an experimental model in rabbits. The following medications were instilled intrapleurally in anaesthetized male rabbits: tetracycline 35 mg.kg-1 or C. parvum 4 or 8 mg, all diluted with bacteriostatic saline solution. Twenty eight days after the instillation, the animals were sacrificed and the pleural spaces assessed macroscopically for evidence of pleurodesis and microscopically for evidence of fibrosis and inflammation. The intrapleural injection of C. parvum was ineffective in creating pleural fibrosis. The mean degree of pleurodesis in the 10 rabbits who received tetracycline was 3.5 +/- 0.7 (scale 0-4) whilst in the 10 rabbits that received 4 mg C. parvum it was 0.0 +/- 0.0, and in the 10 rabbits that received 8 mg C. parvum it was 0.5 +/- 0.8. Based on this study, we recommend that C. parvum should not be used as a pleural sclerosant in patients with normal pleura.

Comparison of silver nitrate and tetracycline as pleural sclerosing agents in rabbits

The ideal agent to produce pleurodesis has not been identified. Tetracycline, the drug used most commonly in the 1980s, is no longer available. Talc either aerosolized or in a slurry is the agent used just most commonly at the present time, but there are concerns about its safety. Another possibility is silver nitrate, which was widely used in the past, but was abandoned on account of side effects. We hypothesized that lower concentrations of silver nitrate than had been used in the past would be effective in creating a pleurodesis in rabbits. The following medications in a total volume of 2 mL were instilled intrapleurally in three groups of ten anesthetized rabbits: 0.25% or 0.50% silver nitrate and 35 mg/kg tetracycline. Twenty-eight days after the injection, the animals were sacrificed and the pleural spaces were assessed grossly for evidence of pleurodesis and microscopically for evidence of fibrosis and inflammation. The intrapleural injection of 0.50% silver nitrate produced an effective pleurodesis. The mean degree of gross pleurodesis in the rabbits that received 0.50% silver nitrate (3.4 +/- 1.2) did not differ significantly from that of the rabbits that received tetracycline (3.5 +/- 0.7) (scale 0 to 4). The mean degree of microscopic pleural fibrosis in the rabbits that received 0.50% silver nitrate (3.4 +/- 0.7) did not differ significantly from that of the rabbits that received tetracycline (3.9 +/- 0.3). However, 0.25% silver nitrate was ineffective in creating pleural fibrosis, either grossly or microscopically. No rabbits died after the intrapleural injection of the drugs. There were no observed side effects after the injection of silver nitrate. The present study demonstrates that 0.50% silver nitrate instilled into the pleural space is an effective agent for producing pleurodesis in the rabbit; its effect is comparable to tetracycline 35 mg/kg. This agent should be compared with tetracycline derivatives and talc in studies in humans.

Theophylline-ranitidine interaction in elderly COPD patients

Most controlled studies in humans indicate that ranitidine does not alter theophylline metabolism, even at high doses. However, there have been several case reports published recently which demonstrate the development of theophylline toxicity mostly in older patients receiving stable oral doses of this drug when ranitidine was administered simultaneously. We studied eleven elderly (mean age, 69.0 +/- 6.2 years) patients with chronic obstructive pulmonary disease (COPD). During one week the patients took slow-release theophylline, 200 mg every 12 h, followed by one week intake of the same dose of theophylline plus ranitidine tablets, 150 mg every 12 h. At the end of each period, blood samples were obtained 0, 1, 2, 3, 4, 5, 6, 7, 8 and 12 h after the morning dose for the determination of serum theophylline levels. The peak theophylline concentration (Tmax) was achieved after 4.1 +/- 0.9 h while the patients were taking theophylline, and after 2.9 +/- 1.4 h with the combined regimen. This difference was statistically significant (P < 0.01). In only 3/11 subjects did Tmax remain unchanged during both phases of the study. The mean theophylline clearance rates while the patients were receiving theophylline alone (39.58 +/- 19.89 ml/min) and when they were receiving both medications (34.42 +/- 10.55 ml/min) were similar. The mean serum levels while the patients were receiving theophylline alone were slightly higher but not statistically different. These results suggest that the reported increases in serum theophylline levels in older patients receiving theophylline and ranitidine cannot be ascribed to slower theophylline metabolism in the geriatric patients with COPD who is also given ranitidine.

Intrapleural talc for the treatment of malignant pleural effusions secondary to breast cancer

BACKGROUND

The management of malignant pleural effusions secondary to breast cancer is a difficult problem. In the 1980s tetracycline was probably the most commonly used sclerosing agent, but parenteral tetracycline is no longer available. Therefore, it is important to evaluate alternative sclerosing agents. This prospective study was designed to determine the efficacy of insufflated talc in producing pleurodesis in patients with pleural effusions secondary to breast cancer.

METHODS

Fifty-two patients admitted between May 1985 and November 1992 to the Department of Thoracic Surgery underwent thoracoscopy and had 2 gm sterile asbestos free talc insufflated throughout the pleural space at the time of the procedure. One or two chest tubes were inserted and left in place until fluid drainage was less than 100 ml per day.

RESULTS

Of the 52 patients, 5 were not evaluable. Two patients died within 30 days of the procedure. In three additional patients the lung did not expand after thoracoscopy. The intrapleural insufflation of talc was effective in preventing recurrence of pleural effusion. At 30 days there was no recurrence of the pleural fluid in 45 of the 47 (95.7%) patients. One of these patients had a recurrence of the effusion 2 months after the procedure but the remaining 44 (93.6%) had no recurrence for the duration of the study. Aerosolized talc was associated with a moderate morbidity. Six (11.5%) patients had re-expansion edema, but all recovered. Empyema developed in one patient after the procedure. No episodes of respiratory distress syndrome were observed after talc pleurodesis.

CONCLUSION

The insufflation of 2 gm talc into the pleural space is an effective method to control pleural effusions secondary to breast cancer.

Arrhythmogenic effects of combined orally administered theophylline and albuterol in patients with chronic obstructive pulmonary disease

1. Studies in asthmatic subjects have reported conflicting results about the arrhythmogenic effects of beta agonist and theophylline. The purpose of the present study was to evaluate the effects of the combination of these drugs in patients with chronic obstructive pulmonary disease (COPD). 2. Twelve COPD patients (FEV1 = 1.2 +/- 0.3 L; PaO2 = 65.7 +/- 9.0 mmHg) were evaluated by 24-h Holter monitoring on three different days. The first evaluation was done after the patient had been without any treatment for at least 24 h, the second after sustained-release theophylline for one week and the third after oral beta agonist (albuterol) and theophylline for one week. 3. Mean serum level of theophylline was 1.9, 15.6 and 11.7 micrograms/ml, and mean heart rate was 78.3, 82.0 and 84.5 beats/min for the first, second and third period, respectively. Four patients showed more than 10 premature atrial contractions/h in the baseline Holter, and this rate did not increase after either treatment. Three patients had more than 10 premature ventricular contractions/h (PVC) at baseline, with no increase while receiving theophylline or the combination of theophylline and albuterol. However, one patient did have worsening of the arrhythmia while taking both drugs. There were 5 single PVCs/h at baseline and 150 single and 9 coupled PVCs/h plus 1 episode of non-sustained ventricular tachycardia during combined therapy. 4. We conclude that the combination of theophylline and a beta agonist (albuterol) may increase the premature ventricular contraction rate and the complexity of ectopic activity in COPD patients.

Distribution of pleural injectate. Effect of volume of injectate and animal rotation

It is controversial whether rotation is necessary for patients undergoing pleurodesis. In addition, the optimal volume of the injectate remains to be determined. The purpose of this study was to determine the importance of rotation and the volume of the agent on the intrapleural dispersion of agents injected into the pleural space of rabbits. Technetium 99m pertechnetate (99mTc) in 0.5, 1.0, or 2.0 ml of saline solution was injected into ten lightly anesthetized rabbits, half of whom were rotated for 1 min after the injection. Static images were obtained in the anterior projection 1 and 5 min after the injection. After the second scan, the limits of the lung were defined by obtaining a perfusion scan immediately after the intravenous injection of macroaggregates of 99mTc-labeled serum albumin. The degree of dispersion was significantly greater in the nonrotated groups both at 1 min (F = 8.11, p = 0.0085) and at 5 min (F = 5.89, p = 0.0274). In addition, the homogeneity of the distribution of the injectate was not improved with rotation. From this study, we conclude that rotation of the animal for 1 min after the intrapleural injection does not improve the distribution of the injectate throughout the pleural space. Furthermore, a volume of 0.5 ml is sufficient for all pleural surfaces to be exposed.

Relationship between pleural effusion and pericardial involvement after myocardial revascularization

The explanation for the high incidence of pleural effusion after cardiac surgery is unclear. There is a high incidence of left pleural effusion with inflammatory pericardial disease. We hypothesized that after coronary artery bypass grafting (CABG) there would be a higher incidence of pleural effusions in patients with pericardial involvement. We prospectively studied 47 patients undergoing elective CABG; 17 had only saphenous vein grafts (SVG group) and 30 received at least one internal mammary artery graft (IMA group) in addition to SVG. Patients had a chest radiograph, chest ultrasound, and an echocardiogram on the 7th, 14th, and 30th postoperative days. Seven days after the surgery, 42 to 47 patients (89.4 percent) had a pleural effusion and 36 (76.6 76.6 percent) pericardial involvement. No relationship was found between the presence of a pleural effusion and a pericardial effusion (p > 0.05). On the 14th postoperative day, 36 patients (76.6 percent) had a pleural effusion while 33 patients (70.2 percent) had a pericardial effusion. There was a significant relationship between the presence of a pleural effusion and a pericardial effusion (p < 0.05). On the 30th postoperative day, 27 patients (57.4 percent) had a pleural effusion and 25 (53.2 percent) had a pericardial effusion. Again, there was a significant relationship between a pleural effusion and a pericardial effusion (p < 0.05). Finally, there was no relationship between the ejection fraction and the presence of pleural effusion at any time (p > 0.05). From this study, we conclude that there is a high prevalence of both pleural and pericardial effusion postoperatively in patients undergoing CABG. Both types of effusions tend to be asymptomatic, gradually disappear, and are more common in the IMA group. Patients who have a persistent pericardial effusion are more likely to have a persistent pleural effusion.

Scimitar sign with normal pulmonary venous drainage and systemic arterial supply. Scimitar syndrome or bronchopulmonary sequestration?

The classic definition of the scimitar syndrome is a triad of hypoplasia of the right lung with anomalous venous drainage and a systemic arterial supply of a variable degree. We report a case in which a scimitar-shaped anomalous vein was observed on the plain chest radiograph, but subsequently a pulmonary angiogram showed that it drained normally into the left atrium.