Evaluation of autoCPAP devices in home treatment of sleep apnea/hypopnea syndrome

BACKGROUND AND PURPOSE

Quality of life (QOL) and sleepiness for patients with sleep apnea/hypopnea syndrome (SAHS) might improve with continuous positive airway pressure devices working in auto-adjust mode (autoCPAP) by allowing pressure modulations following patient needs. Clinical comparisons between devices driven by different algorithms are needed.

METHODS

We compared the clinical effectiveness of fixed pressure CPAP and four different autoCPAP devices by assessing compliance and QOL (36-item short-form health survey [SF-36]). SAHS patients were randomly allocated to five groups. Polysomnography (PSG) was performed to titrate the effective pressure in the constant CPAP group and evaluate residual apnea/hypopnea index (AHI) under autoCPAP. Follow-up consisted of clinical visits at three and six months by homecare technicians who assessed compliance, symptom scores and SF-36 scores. A laboratory-based PSG using the same CPAP/autoCPAP device as at home was performed at six months.

RESULTS

Eighty-three patients (mean age 56+/-10 yrs) with mean body mass index (BMI) 30.8+/-5.3 kg/m(2) and severe SAHS (mean AHI: 52.3+/-17.8/h) were included. There were no differences in clinical symptoms or QOL scores, and similar clinical and PSG improvements were seen in all groups. CPAP use was >5 h per night, without any significant difference between groups.

CONCLUSIONS

AutoCPAP is equally as effective as fixed CPAP for long-term home treatment in severe SAHS patients.

Effect of sleep apnea syndrome on the circadian profile of cortisol in obese men

It has been hypothesized that sleep apnea syndrome (SAS) increases hypothalamic-pituitary-adrenal axis activity and, through increased cortisol levels, participates in the pathophysiology of metabolic and cardiovascular complications. We compared the circadian profiles of cortisol in obese men with [obSAS+; apnea-hypopnea index (AHI) >or= 20/h] and without SAS (obSAS-; AHI <or= 5/h). 1) Salivary cortisol (5 samples: before/30 min after dinner, 2100, upon/30 min after awakening) was measured in 15 obSAS+, 19 obSAS-, and 19 normal-weight controls (NWC). 2) Plasma cortisol (every 30 min for 24 h under highly controlled conditions and portable EEG device) was measured in 9 obSAS+, 8 obSAS-, and 10 NWC men. Visceral adipose tissue surface was measured by CT scan. In both studies, obSAS+ and obSAS- men were comparable for age, BMI, waist circumference, and waist-to-hip ratio. First, no difference was found, using ANOVA for repeated measures, between obSAS+ and obSAS- subjects for any salivary cortisol measurement. No correlation was found between salivary cortisol and AHI or nocturnal SaO(2). Similarly, obSAS+ and obSAS- men showed no difference in plasma cortisol rhythmicity: 24-h minimum, maximum, and mean, ANOVA for repeated measures, mathematical modeling of cortisol rhythm (COSINOR), and morning secretory peak. Conversely, ANOVA for repeated measures showed decreased cortisol levels in obese vs. NWC men during both the trough (2200-0130) and the peak (0600-0900) independently of SAS status. We show that SAS per se is not associated with any change of the level or of the features of salivary and plasma cortisol rhythmicity and confirm that men with visceral obesity display lower plasma cortisol levels than NWC men.

A multicentre trial of education strategies at CPAP induction in the treatment of severe sleep apnoea–hypopnoea syndrome

BACKGROUND AND PURPOSE

Compliance with continuous positive airway pressure (CPAP) treatment in obstructive sleep apnoea syndrome (OSAS) may be difficult. Patient education is important but strategies and their outcomes are not clear.

PATIENTS AND METHODS

We studied the effects of four education strategies on compliance and quality of life changes with CPAP treatment in seven centres in the French ANTADIR homecare network. Patients received from prescribers either a simple oral explanation (SP) or an oral and written explanation (RP) of CPAP use. In addition, they received from homecare technicians either a single home visit (SH) at CPAP onset or repeated home visits at CPAP onset and at 1 week, 1 month and 3 months after (RH). Compliance and quality of life were evaluated at CPAP onset, and at 3, 6 and 12 months after initiation of treatment.

RESULTS

One hundred twelve patients with severe OSAS (mean age 58+/-11 year, apnoea-hypopnoea index 58+/-25/h) were allocated randomly to groups (SP+SH; SP+RH; RP+SH; RP+RH) with no initial differences. Quality of life, evaluated by the generic SF-36 questionnaire, improved in the combined emotional domains. Compliance was over 5h in all four education groups. These effects were sustained over 12 months and were not different between the four groups. We conclude that standard education strategies for CPAP induction in France are sufficient for good compliance and improved quality of life with CPAP. Education with reinforced input should be focussed on identified subgroups prone to problems.

[Sleep apnea syndrome after total laryngectomy]

INTRODUCTION

Tracheostomy was the treatment of choice for sleep apnoea syndrome before nasal continuous positive airway pressure was developed. The occurrence of sleep apnea syndrome after total laryngectomy is unusual.

CASE REPORT

The authors report the case of a 73 year-old man presenting with the symptomatology of sleep apnoea syndrome, several years after a total laryngectomy for cancer. The polysomnographic recording confirmed severe sleep apnoea syndrome with an apnea-hypopnea index of 89. Clinical examination showed a marked reduction in the diameter of the tracheostomy orifice during forced inspiration whilst lying supine. The combination of negative airway pressure and muscle hypotonia during sleep could explain this closure. Use of a silver tracheostomy cannula reversed the symptoms and normalised the apnea-hypopnea index.

CONCLUSION

Sleep apnea syndrome is an unusual complication of total laryngectomy, resulting from collapse of the tracheostomy walls during sleep, which can be treated by the insertion of a silver tracheostomy tube.

Carboplatin-etoposide combination in small cell lung cancer patients older than 70 years: a phase II trial

BACKGROUND

No standard treatment is defined for elderly patients with small cell lung cancer (SCLC). Carboplatin and etoposide are highly active agents against SCLC. In this study, we evaluated the activity and toxicity of a combination of these two agents.

PATIENTS AND METHODS

Thirty-four untreated patients with limited or extensive SCLC and median age of 73.9 years entered the study. Chemotherapy consisted of carboplatin i.v. on day 1 (AUC 5 using Calvert's formula) and etoposide 100 mg/m(2) given orally on days 1-5, every 4 weeks, and thoracic irradiation was given to limited disease patients after chemotherapy.

RESULTS

The overall response rates was 59% (95% CI: 43-76). The median survival for all patients was 37 weeks (range 3-76 weeks). The toxicity was mainly haematological with grade 3-4 neutropenia in 59% of courses, febrile neutropenia in 15% of courses, and toxic death in 9% of patients.

CONCLUSION

The results of this regimen are disappointing with worse response and survival, and more haematological toxicity than expected and previously reported, despite the use of Calvert's formula. Possible explanations are the use of etoposide per os rather than i.v., the frequent comorbidities of older patients and the inclusion of patients with poor prognosis factors.

[Motor control of the upper airways]

During sleep upper airway resistance increases proportionally with a slightly diminished air flow. This can however be compensated for by increasing inspiratory force that further aggravates airway collapse and resistance. Apnea during sleep results from an interaction between the different respiratory and pharynx muscles. Sleep modifies the activity of these muscles leading to increased resistance and muscle fatigue, then eventually histological modifications. Electrical activity is not always proportional to the generated force and muscle shortening, so the effect is not always an increased permeability. In apneic patients, the efficacy of these muscles is preserved but tissue response may be poor. Histological adaptations are variable and depend on the level of the pharynx and the variability of the site of obstruction. This raises the question of electrical stimulation of certain muscles and the choice of the site of stimulation.

Simultaneous laboratory-based comparison of ResMed Autoset with polysomnography in the diagnosis of sleep apnoea/hypopnoea syndrome

ResMed Autoset (AS) is a simplified diagnosis system for obstructive sleep apnoea/hypopnoea syndrome (OSAS) based on the respiratory flow/time relationship by pressure variation measured through simple nasal prongs. A multicentre prospective trial was used to compare AS and polysomnography (PSG) for diagnosing 95 patients, with suspected OSAS. Physicians gave a pretest probability of the patient having OSAS. The apnoea/hypopnoea index (AHI) was compared between the two methods of diagnosis for the whole population and for subgroups according to the pretest probability. Twenty-four patients had AHI < 15 events x h(-1) on PSG and 19 AHI 15-30, and 52 patients had AHI > or = 30. Correlation between AHI assessed by AS and PSG was r=0.87 for total sleep time (TST), p<0.0001. A Bland and Altman plot gave an agreement between the two methods of +/-40%. For a threshold of AHI > or = 15 events x h(-1) to diagnose OSAS, AS has a sensitivity of 92%, specificity of 79%, positive predictive value of 93% and negative predictive value of 76%. With a pretest probability > or = 80%, sensitivity and positive predictive value were 98 and 100% respectively. Of six false negative, four had a high pretest probability (> 80%) or Epworth score > or = 10. Using these parameters as a criterion for proceeding to PSG after a negative AS study would mean that two apnoeic patients (AHI 20 and 17 events x h(-1) by PSG) would escape detection. The Autoset is useful for the detection of obstructive sleep apnoea but with high pretest probability and a negative Autoset result polysomnography should be performed.

Color density spectral array for quick evaluation of sleep during nasal continuous positive airway pressure

EEG color density spectral array enables quick evaluation of sleep. The aim of the study was to evaluate if an easily calculated sleep score based on this method could be used to assess the improvement of sleep after nasal continuous positive airway pressure (CPAP) in patients with sleep apnea syndrome (SAS). Eight hours of sleep are displayed on a single sheet along with EEG amplitude, 2 EEG channel spectra (FFT), electromyogram envelope and electro-oculogram. The x-axis corresponds to time, the y-axis to EEG frequency (range 0-16 Hz), and the color to the frequency power. This system allows the detection of sleep spindles, REM sleep and deep sleep (stages 3 and 4) as well as the evaluation of the sleep cyclic organization and its fragmentation by apnea. Based on these findings a sleep score is calculated. Eight young normal subjects were successively recorded as well as 15 SAS patients and with and without nasal CPAP. During the 1st night, the sleep score was lower in SAS patients than in normal subjects. With CPAP the apnea number decreased and the sleep score returned to normal in all patients except 1. A positive correlation was found between sleep score and duration of stage 2, stage 3 or REM sleep. A negative correlation was found between sleep score and the apnea index. This sleep score enables a quick and reliable evaluation of sleep in patients with SAS before and during nasal CPAP.

Relation between polysomnographic parameters and apnea index in obstructive sleep apnea syndrome

We performed overnight polysomnography in 77 patients for diagnosis of sleep apnea syndrome (SAS) and assessment of severity. Patients were classified into 3 groups according to apnea index (AI): group 1 (G1; no SAS), AI < or = 10 (21 patients), group 2 (G2; moderate SAS), 10 < AI < 40 (34 patients), and group 3 (G3; severe SAS), AI > or = 40 (22 patients). In all 3 groups, 60% of the apneas were obstructive, but the proportion of mixed apnea increased from G1 to G3 (6% in G1, 12% in G2, and 24% in G3). The duration of REM sleep was shorter in G2 and G3 than in G1 (G1 61 min, G2 44 min, G3 41 min; p < 0.03). In G3 a dramatic decrease in deep sleep was noted in comparison with G1 and G2 (G1 29 min, G2 31 min, G3 10 min). The distribution of the apnea in the different sleep stages was similar in G3; in G2, 16 patients had a REM apnea predominance, but in this subgroup duration of REM sleep was longer and AI was lower than in the other 18 G2 patients. So, absence of sleep stage apnea predominance and high proportion of mixed apnea were observed in the most severe SAS.

End-tidal CO2 analysis in sleep apnea syndrome. Conditions for use

The diagnosis of sleep apnea syndrome (SAS) requires expensive and complex instrumentation. The purpose of the present study was to determine the value of end-tidal CO2 (EtCO2) in screening for sleep apneas. Thirty-nine patients referred to our sleep laboratory because of suspected SAS and ten normal subjects were studied. The EtCO2 was measured using an infrared spectrometer (POET) designed for simultaneous measurement of CO2 and pulse oximetry. In 29 subjects, expired gas was sampled with a nasobuccal mask (Respiron) with lateral orifices. In the other 20 subjects, sampling was done with nasobuccal prongs (Criticare) comprising a four-channel plastic tube to the mouth and the nostrils. Data from an 8-h night were transferred the following day to a microcomputer (Apple Macintosh) for processing. Apnea was defined as an absence of detection of CO2 for more than 10 s. Conventional polysomnography was performed (Respisomnographe). The number of apneas in 8 h and the apnea index (number of apneas in 1 h) were calculated after visual analysis on the screen of the polysomnograph and also with EtCO2 analysis. For recordings made with a nasobuccal mask, the regression curve between the apnea indices computed with EtCO2 and polysomnography was an order 2 polynomial curve (r = 0.76; p < 0.001), with an inflection point at 39 apneas per hour. For recordings with nasobuccal prongs, the correlation was very significant (r = 0.95; p < 0.0001), and the regression curve was linear. The EtCO2 with nasobuccal prongs appears to be a simple and reliable method for screening for SAS.

Correlations between theophylline concentrations in plasma, erythrocytes and cantharides-induced blister fluid and peak expiratory flow in asthma patients

Theophylline levels in plasma, erythrocytes and cantharides-induced blister fluid (BF) have been correlated with peak expiratory flow (PEF) in asthmatic patients. Nine asthmatic men received an IV infusion of 240 mg theophylline at a constant rate for 30 min. The theophylline concentrations in erythrocytes and blister fluid were 37% and 78% of those in plasma. There was not a strong correlation between erythrocyte or blister fluid penetration and the clinical effect of theophylline.

Vascular and cardiac reactivity in pulmonary hypertension due to chronic obstructive lung disease: assessment with various oxygen concentrations

The aim of the present work was to evaluate vasoreactivity in patients with pulmonary hypertension related to chronic obstructive lung disease. This was done by comparing haemodynamic data recorded while patients were breathing room air, and hypoxic and hyperoxic mixtures. We estimated the role of vasoconstriction in determining the level of pulmonary hypertension. This study included 26 patients with moderate pulmonary hypertension mean pulmonary arterial pressure (MPAP) = 27.3 +/- 1.2 mmHg) secondary to chronic obstructive lung disease (COLD), forced expiratory volume in one second (FEV1) = 0.95 +/- 0.13 l; arterial oxygen tension (PaO2) = 8.7 +/- 0.25 kPa). After insertion of a thermodilution catheter in the pulmonary artery and a cannula in the femoral artery, mixtures containing 15, 21, 30 and 100% oxygen were randomly administered for 20 min each. As fractional inspiratory oxygen (FIO2) increased, MPAP decreased relatively less than cardiac index. Cardiac output was at its highest during room air breathing and the hypoxic mixture did not lead to a further increase. Unlike normal subjects, in whom adjustment of cardiac output is achieved by heart rate alone, haemodynamic regulation in these patients also involved stroke volume. Variations in MPAP and cardiac index were strongly correlated with arterial oxygen saturation (SaO2). The greatest variations were noted in the patients with the highest pulmonary hypertension. Under normoxic and hyperoxic condition the relationship between pulmonary artery driving pressure and cardiac index was linear and its slope steeper in patients having the highest pulmonary hypertension at steady-state.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of a constant dose rate of terbutaline on circadian peak expiratory flow, heart rate and systolic arterial pressure in patients with asthma exacerbation

The purpose of this study was to investigate the effect of a constant infusion rate of terbutaline on circadian bronchial peak expiratory flow rate (PEFR), heart rate and arterial pressure in patients with asthma exacerbation. Fifteen hospitalized asthmatic patients (6 females and 9 males, mean age 43.3 years, mean weight 67.0 kg) were included in this study. In order to reach the desired plasma concentrations of terbutaline immediately, a pharmacokinetic simulation was done. Based on the predicted values thus obtained, an initial 5-min bolus dose of 2.94 micrograms/kg was given to all patients at 7 a.m., i.e. at the beginning of the study. Over the following 24 h (7 a.m. to 7 a.m.), 33 micrograms/kg of terbutaline was infused intravenously at a constant rate with an electric pump. Since severe acute asthma requires corticosteroids, a 40-mg injection of methylprednisolone was given to all patients at 7 a.m. PEFR, heart rate, systolic arterial pressure, side effects and plasma terbutaline levels were recorded at 7 and 10 a.m., 1, 4, 7 and 11 p.m., and 3 and 7 a.m. the following morning. Terbutaline had a significant favorable effect on asthma exacerbation but no circadian rhythm was found in PEFR. Although terbutaline was infused at a constant rate, plasma levels depended on circadian variations.

[Treatment of pulmonary artery hypertensions]

The pulmonary hypertension (PAH) in chronic obstructive lung disease include therapy of the respiratory disease i.e. bronchodilator, kinesitherapy. Long-term oxygen therapy (more than 15 h/day) reverse the course of PAH and increase survey. Long-term efficiency of vasodilators is not well demonstrated. Primary PAH could benefit from vasodilators, especially waiting lung or heart-lung transplantation. Patients with PAH secondary to respiratory insufficiency could also be successfully transplanted. In post embolic PAH, antithrombotic agents are useful. Thrombectomy or transplantation are sometimes proposed.

Uvulopalatopharyngoplasty in snorers with sleep apneas: predictive value of presurgical polysomnography

To determine its predictive value, polysomnography was performed on 14 snorers with sleep apnea syndrome (SAS) before and 3 months after uvulopalatopharyngoplasty (UPPP). In the 8 patients considered as cured (less than 10 apneas per hour after UPPP), total apnea index (TAI) decreased from 29.7 +/- 22.6 to 4.9 +/- 3.5. Rapid eye movement sleep (REM) increased from 10.9 +/- 3.6 to 14 +/- 5.7% of the total sleep period (TSP). In the 6 uncured patients, TAI decreased from 59.7 +/- 15.7 to 32 +/- 15.7 and REM increased from 7.7 +/- 5.6 to 15.8 +/- 7.2% of TSP. Snoring and drowsiness decreased in both cured and uncured patients. A presurgical apnea index less than 40 seems to be a reliable predictor of successful UPPP. The association of obstructive apnea with either central apnea or mixed apnea was not a factor of poor prognosis. Better sleeping could explain in part the clinical improvement in both cured and uncured patients, but postoperative polysomnography is needed to detect asymptomatic SAS.

Unequal day-night terbutaline i.v. dosing in acute severe asthma: effect on nocturnal bronchial patency, heart rate, and arterial pressure

Our study investigated the differential effects of continuous or unequal day-night terbutaline dosing on circadian bronchial patency, heart rate, and arterial pressure in severe acute asthma. Forty-five hospitalized asthmatic patients (19 women and 26 men, mean age 45.4 years, mean weight 63.5 kg) were included in this multicenter study. Three groups of patients (corresponding to three dosing schedules) were randomized; the three groups were comparable, since no statistically significant difference was detected in the age, weight, or peak expiratory flow values at the beginning of the study. In order to reach immediately the concentrations of terbutaline corresponding to the desired unequal day-night concentrations, a theoretical pharmacokinetic simulation was done to predict the outcome in terms of the plasma concentrations after the three dosing regimens; the results of this simulation allowed us to calculate the initial bolus dose to be given over 5 min to groups A, B, and C, i.e., 1.47, 2.94, and 4.41 micrograms/kg, respectively. This bolus was given to all patients at 0700 h, the beginning of the study.(ABSTRACT TRUNCATED AT 250 WORDS)

Respiratory effects of pollution

Atmospheric pollution is increasingly responsible for chronic airway disease. Although outdoor pollution has decreased somewhat in recent years, indoor pollution has increased. Outdoor pollution results essentially from the combustion of coal and other fuels used for heating, industrial production and motor vehicles. The major sources of indoor pollution are heating and cooking devices. The main pollutants are suspended particulates, SO2, NO2 in indoor pollution and ozone which is linked to the photochemical effects. Transient increases in pollution cause transient decreases in pulmonary airflow. Chronic pollution seems to lead to an increase in the prevalence of lower and upper respiratory airway symptoms. In young children early exposure to pollution contributes to the development of chronic airways disease later in life. Asthmatics are at greater risk for pollution-related complications and several pollutants are known to increase bronchial reactivity. Further efforts are needed to reduce in pollution indoor and outdoor environments in particular with regard to tobacco smoke and especially for children.

Comparison of Berodual and salbutamol in asthma: a multicenter evaluation

A 2-month study was carried out to compare the efficacy and safety of Berodual (B) (Boehringer Ingelheim) and salbutamol (S) in asthma. B is a combined agent with 20 micrograms of ipratropium bromide and 50 micrograms of fenoterol in each metered aerosol puff. Each puff of S contained 100 micrograms of drug. 196 patients were included in the study and received 4 x 2 puffs a day of either B or S. FEV1 and FVC were measured every month, and peak expiratory flow rate (PEFR) 4 times a day, i.e. morning and evening before and after administration of drug. Improvement of PEFR was the same in the two groups. No tachyphylaxis occurred. No difference was observed between the two drugs with regard to heart and respiratory rate, dyspnea and blood pressure. Tremor seemed less frequent with B but this difference was not statistically significant. B achieved the same effects as S though containing less beta-2-agonist agent.

[Long-term treatment of pulmonary hypertension in chronic obstructive bronchopneumopathies with nifedipine. Hemodynamic study over 18 months]

The objective of this study was to evaluate the long-term results of an 18 months nifedipine treatment in patients with pulmonary hypertension (PHT) secondary to chronic obstructive broncho-pulmonary disease (COBPD). The possible alterations of the pulmonary vascular reactivity after such chronic treatment were also studied. 20 patients presenting a PHT secondary to a COBPD were randomly distributed in two equal groups: a reference group and a group treated with nifedipine. The haemodynamic work-up and blood gases measurements of patients from both groups as well as the effects of acute sublingual administration of 10 mg of nifedipine were performed at the beginning of the study, under stable conditions. After this initial test, the patients in the treated group, received 30 mg/day of nifedipine per os. The same measurements and pharmacological tests were carried out after 18 months, 24 hours after the treatment was discontinued. All patients completed the study; no adverse reaction was noted, especially no major desaturation. A significant decrease of the cardiac index (p 0.05) was noted in the reference group (-10%). No significant alteration of the pulmonary pressure and resistance, of the blood gases, was noted. The haemodynamic variations during acute testing were similar in both groups before and at the end of the observation period. Chronic administration of nifedipine may prevent the decrease of the cardiac index in patients presenting a PHT secondary to COBPD. The pulmonary vascular reactivity is not affected by this type of treatment.

[Time-related distribution of delayed-action theophylline in the treatment of chronic obstructive bronchopneumopathies]

Three regimens of sustained-release theophylline (Theostat) were administered to 12 male patients with chronic obstructive lung disease in randomized cross over trial. Each 7 days' treatment consisted of: treatment A: 8 mg/kg/day at 07.00 h and 4 mg/kg/day at 19.00 h; treatment B: 6 mg/kg/day at 07.00 h and 6 mg/kg/day at 19.00 h; treatment C: 4 mg/kg/day at 07.00 h and 8 mg/kg/day at 19.00 h. Peak expiratory flow was recorded each day at 07.00, 11.00, 15.00, 19.00 and 23.00 hours, and theophylline plasma levels were determined on the 7th day of each treatment sequence. Cosinor analysis of the data revealed significant circadian rhythms of 24 hr mean Peak expiratory flow for each treatment: the mesor was significantly higher with C and acrophases were located at 14.26 for A, 14.25 for C; a phase shift of the acrophase was detected for B (09.58). These data suggest that an unequal twice daily sustained-release theophylline dosing with higher dose in the evening may be beneficial in the treatment of chronic obstructive lung disease.

Enoxacin in the treatment of lower respiratory tract infections

Twenty patients admitted to hospital with serious lower respiratory tract infections entered an open study of 400 mg enoxacin given orally twice a day for a minimum of seven days. Clinical signs and symptoms were completely cured or improved in six of eight patients with pneumonia, in nine of ten patients with bronchitis, and in two patients with bronchiectasis. Enoxacin was effective in eradicating the initial pathogens in 10 of 12 patients with positive cultures. Enoxacin was well tolerated. Only one treatment-related side-effect was observed during the study. Nine patients received concurrent treatment with theophylline, but no signs of theophylline toxicity were seen. Enoxacin is a safe and effective alternative to parenteral treatment of lower respiratory tract infections.

One-year clinical study on nifedipine in the treatment of pulmonary hypertension in chronic obstructive lung disease

The advantages of long-term administration of vasodilators in the treatment of chronic cor pulmonale were investigated after informed consent in 60 patients with obstructive respiratory insufficiency (56 men, 4 women, mean age 63.5 +/- 1.5 years; mean pulmonary pressure 30.4 mm Hg). They were randomly divided into two groups of 30, a control group and a group treated with nifedipine, 10 mg three times a day. The following parameters were recorded every 3 months for a year: dyspnea, degree of right ventricular failure, number of days spent in hospital, survival and arterial blood gas tension. On the first day of study, no significant difference existed between the control and the treated groups. After 1 year 22 patients in the control group were still followed and 8 were dead. In the treated group 19 were followed, 7 were dead and 4 stopped treatment, generally due to ankle edema. At the end of the study, the only significant modification was improvement of the dyspnea in the nifedipine group (p less than 0.01). In conclusion, in spite of an improvement in the dyspnea index, clinical study for 1 year failed to demonstrate any objective benefit of nifedipine treatment.

Hemodynamic effects of a single dose of dopamine and L-dopa in pulmonary hypertension secondary to chronic obstructive lung disease

Dopamine (DA) has rarely been administered at low dosage to stable patients with pulmonary hypertension (PAH) secondary to chronic obstructive lung disease (COLD). Since L-dopa (L-DA) is metabolized into DA, it might be an oral source of DA. After informed consent 10 patients with PAH, secondary to COLD underwent right catheterization to allow measurements of pressures and cardiac output (CO) as well as arterial and mixed venous oxygen levels before and then 30 and 60 min after the beginning of intravenous DA at a rate of 4 micrograms/kg/min. A week later, the same parameters were remeasured in 5 of these patients after a single oral intake of 1.5 g L-DA. At low doses both DA and L-DA increased CO and decreased pulmonary vascular resistances, suggesting a pulmonary vasodilator effect. They also enhanced oxygen delivery and Pvo2 without decreasing Pao2. A correlation was observed between cardiac index and plasma DA level. Thus though they do have some immediate adverse side effects and their long-term effects are unknown, inotropic and vasodilator drugs may have positive effects on pulmonary circulation.

Role of the quaternary ammonium ion determinants in allergy to muscle relaxants

Anaphylaxis to muscle relaxants appears to be a very useful model to study the IgE-dependent mechanisms of mediator release in humans. The serum IgE binding sites of the drugs appeared to be the ammonium ion determinants. In patients allergic to suxamethonium, one of the most frequently used muscle relaxants for general anesthesia, significant histamine release could be obtained in each case with simple diammonium salts. The length of the chain linking the ammonium groups appears to play an important role. In fact, when the length was less than or equal to 4 A, no significant histamine release could be obtained, whereas the optimal length for histamine release appeared to be greater than or equal to 6 A. Furthermore, muscle relaxants with a rigid backbone between the ammonium determinants (such as pancuronium) are less active than flexible molecules (such as suxamethonium) in initiating mediator release. This study suggests that small divalent molecules can induce anaphylactic shock in sensitized patients and that the length and the flexibility of the chain bearing the haptenic determinants appear to be important factors in the elicitation of mediator release.

Unequal twice-daily, sustained-release theophylline dosing in chronic obstructive pulmonary disease

Three regimens of sustained-release theophylline (SRT), Theostat were administered to 12 male patients with chronic obstructive pulmonary disease in a randomized cross-over trial. Each 7-day treatment consisted of: treatment A--8 mg/kg at 0700 hr and 4 mg/kg at 1900 hr, treatment B--6 mg/kg at 0700 hr and 6 mg/kg at 1900 hr, treatment C--4 mg/kg at 0700 hr and 8 mg/kg at 1900 hr. Peak expiratory flow (PEF) was recorded each day at 0700, 1100, 1500, 1900 and 2300 hr and theophylline plasma levels were determined on the 7th day of each treatment sequence. Cosinor analysis of the data revealed significant circadian rhythms in PEF for each treatment: the mesor (24-hr average) was significantly higher with C and acrophases (phi, peak time of PEF rhythm) were located at 1426 hr for A and 1425 hr for C; a shift of the acrophase to an earlier timing was detected for B (phi = 0958 hr. These findings suggest that an unequal, twice-daily SRT dosing with the greater amount of drug at night may be beneficial in the treatment of COPD.

Hemodynamic and oxygen delivery responses to nifedipine in pulmonary hypertension secondary to chronic obstructive lung disease

The effects of a single dose of nifedipine (20 mg sublingually) on hemodynamics and tissue oxygenation were evaluated in 24 patients suffering from pulmonary hypertension secondary to severe chronic obstructive lung disease. A significant improvement in pulmonary circulation and right ventricular pump function occurred. An increase in the oxygen delivery to the tissue was also demonstrated. A complementary study in 10 patients showed that the effects observed after a single dose were still apparent after oral intake (30 mg/day) for 15 days. For these reasons nifedipine may contribute in the treatment of cor pulmonale.

Relationship between inflammation, alpha-1-acid glycoprotein and lidocaine tolerance during fiber-optic bronchoscopy

The purpose of this study was to determine the relationship between inflammation, increased alpha-1-acid glycoprotein (AAG), and lidocaine tolerance during fiber-optic bronchoscopy. Previous studies indicate that serum lidocaine levels vary widely from one individual to another. One reason for these variations may be the presence of an ongoing inflammatory process, which enhances serum AAG, a major binding protein of lidocaine. To test this hypothesis, we assayed free and bound lidocaine as well as AAG in the blood of 12 patients after administration of 9 mg/kg of lidocaine during fiber-optic bronchoscopy. Some of the subjects had clear evidence of inflammation or infection. A correlation was found between AAG and total and bound lidocaine but not between AAG and free lidocaine (which remained almost constant). Thus, in spite of the high total levels of lidocaine observed in some patients with inflammatory processes, the free fraction (which is the active and toxic fraction) remained low.

Comparative study of the respiratory effects of two beta 1-selective blocking agents atenolol and bevantolol in asthmatic patients

Seven asthmatic patients were given a single placebo tablet in a first test session and then in two subsequent double blind sessions they randomly received 400 mg bevantolol or 100 mg atenolol, with at least 2 days between each of the sessions. Neither beta-blocker had any significant effect on FVC as compared to the placebo. FEV 1, however, was significantly lower 2 and 3 h after atenolol or bevantolol; there was no significant difference between the effects of the two drugs on FEV 1. Peak expiratory flow rate was reduced by bevantolol but not by atenolol, the difference reaching significance after 3 h. Fenoterol inhalation at the end of each test session always enhanced pulmonary performance, but to a lesser extent after bevantolol than after placebo or atenolol. A slower heart rate was recorded 2, 3, and 4 h after bevantolol and 3 and 4 h after atenolol; the mean 2-h value was significantly lower with atenolol than with bevantolol. No patient suffered any adverse effect. Bevantolol may be slightly less selective than atenolol.

[Nifedipine in the treatment of chronic cor pulmonale]

The effects of a single dose of nifedipine (20 mg sublingual) on the haemodynamics and parameters of tissue oxygenation were assessed by right heart catheterisation and oximetry of mixed arterial and venous blood in 24 patients with pulmonary hypertension secondary to severe chronic obstructive airways disease. The haemodynamic effects of 15 days' oral therapy (30 mg/day) were studied in 10 other patients. Significant improvement in right ventricular pump function (25 p. 100 increase in cardiac index. average reduction of 3 mmHg of right ventricular end diastolic pressure), and lowering of pulmonary hypertension (mean pulmonary artery pressures reduced by an average of 10 p. 100 and total pulmonary resistance by 25 p. 100) were observed after the single dose of nifedipine. This improvement was maintained after oral therapy for 15 days. The significant improvement of tissue oxygenation was reflected by an increase in oxygen transport (+ 24 p. 100), in the coefficient of delivered oxygen (+ 19 p. 100), in the oxygen partial pressure (+ 4 p. 100) and saturation (+ 3 p. 100) in the mixed venous blood. Arterial lactate concentrations fell by about 28 p. 100. In addition, a moderate fall in ppO2 and arterial saturation was observed due to a weak shunt effect which was more than compensated by the increase in cardiac output, and especially by the increase in the coefficient of relieved oxygen. These results show that nifedipine may be a valuable addition in the treatment of cor pulmonale secondary to chronic obstructive airways disease by improving right ventricular haemodynamics and pulmonary circulation and by increasing the quantity of oxygen delivered.

Two-week nifedipine treatment for pulmonary hypertension complicating chronic obstructive lung disease

The effects of nifedipine on hemodynamics and blood gases were studied in 10 patients with pulmonary hypertension secondary to chronic obstructive lung disease. Two different sets of test data were recorded. The first set of readings was taken immediately before and during the initial hour after sublingual administration of 20 mg of nifedipine. The second set was taken after 2 weeks of therapy with 3 X 10 mg per day. After the acute sublingual dose, a significant decrease in pulmonary arterial pressure and pulmonary vascular resistance was recorded: 13% and 26% respectively. This decrease was accompanied by a 32% increase in cardiac output. Similar findings were recorded at the end of the 2-week therapy. Moreover, at this time, although blood gas tension had not been significantly altered, oxygen delivery was 35% higher. No adverse side effects were observed. This study suggests that nifedipine therapy can improve hemodynamics and tissue oxygenation in patients with pulmonary hypertension complicating chronic obstructive lung disease.

[Effect of captopril on pulmonary arterial hypertension in congestive heart failure associated with chronic obstructive bronchopneumopathy]

Acute hemodynamic effects of oral 25 mg of the angiotensin converting enzyme inhibitor captopril were studied in 8 patients suffering from left ventricular failure and severe chronic obstructive lung disease (COLD) with pulmonary hypertension. In all the patients left ventricular failure resulted from a dilated cardiomyopathy. No significant change in right or left ventricular function and a decrease of 10% in arterial blood pressure and total systemic resistances were observed after administration of captopril. It is suggested that patients suffering from left ventricular failure and severe chronic obstructive lung disease will not benefit from administration of captopril.

[Plasma concentrations of lidocaine in bronchial fibroscopy]

Certain accidents related to local anaesthesia during bronchial fibroscopy may be due to overdosage of local anesthetic drugs. In view of the various techniques employed, the various doses used and the different serum levels obtained, we decided to study the passage of lidocaine into the systemic circulation during bronchial fibroscopy in order to confirm that the doses required for good anaesthesia are not toxic. We studied the kinetics of lidocaine on 10 occasions in 9 patients. All patients had normal renal, hepatic and cardiac function. The anaesthetic was administered in standardized doses (by pharyngo-laryngeal spray of a 5% solution followed by injection via a laryngeal syringe and finally by the operating lumen of the fibroscope with a 1% solution). The total dose of anaesthetic was administered at the beginning of the examination in order to avoid contamination of the aspirated secretions after connection of the traps. The mean dose administered was 9.2 +/- 0.5 mg/kg (range of 380 to 800 mg). The maximal serum levels never attained toxic levels (9 mcg/ml). The highest levels (7 mcg/ml and 5.7 mcg/ml) were observed in a patient with a bronchial epithelioma, normal biochemistry and normal liver ultrasonography, who died two months later with hepatic metastases. The mean maximal serum levels for this group of patients was 2.8 +/- 0.6 mcg/ml between the 5th and 45th minute, which is equivalent to anti-arrhythmic doses (therapeutic level of 1.2 to 5 mcg/ml). The levels obtained are not negligible, but they achieve very good quality anaesthesia with a good margin of safety, apart from the one case with hepatic metastases.