Implementation of a re-linkage to care strategy in patients with chronic hepatitis C who were lost to follow-up in Latin America

To achieve WHO's goal of eliminating hepatitis C virus (HCV), innovative strategies must be designed to diagnose and treat more patients. Therefore, we aimed to describe an implementation strategy to identify patients with HCV who were lost to follow-up (LTFU) and offer them re-linkage to HCV care. We conducted an implementation study utilizing a strategy to contact patients with HCV who were not under regular follow-up in 13 countries from Latin America. Patients with HCV were identified by the international classification of diseases (ICD-9/10) or equivalent. Medical records were then reviewed to confirm the diagnosis of chronic HCV infection defined by anti-HCV+ and detectable HCV-RNA. Identified patients who were not under follow-up by a liver specialist were contacted by telephone or email, and offered a medical reevaluation. A total of 10,364 patients were classified to have HCV. After reviewing their medical charts, 1349 (13%) had undetectable HCV-RNA or were wrongly coded. Overall, 9015 (86.9%) individuals were identified with chronic HCV infection. A total of 5096 (56.5%) patients were under routine HCV care and 3919 (43.5%) had been LTFU. We were able to contact 1617 (41.3%) of the 3919 patients who were LTFU at the primary medical institution, of which 427 (26.4%) were cured at a different institutions or were dead. Of the remaining patients, 906 (76.1%) were candidates for retrieval. In our cohort, about one out of four patients with chronic HCV who were LTFU were candidates to receive treatment. This strategy has the potential to be effective, accessible and significantly impacts on the HCV care cascade.

SARS-CoV-2 vaccination and risk of severe COVID-19 outcomes in patients with autoimmune hepatitis

Background

Data regarding outcome of Coronavirus disease 2019 (COVID-19) in vaccinated patients with autoimmune hepatitis (AIH) are lacking. We evaluated the outcome of COVID-19 in AIH patients who received at least one dose of Pfizer- BioNTech (BNT162b2), Moderna (mRNA-1273) or AstraZeneca (ChAdOx1-S) vaccine.

Patients and methods

We performed a retrospective study on AIH patients with COVID-19. The outcomes of AIH patients who had acute respiratory syndrome coronavirus 2 (SARS-CoV-2) breakthrough infection after at least one dose of COVID-19 vaccine were compared to unvaccinated patients with AIH. COVID-19 outcome was classified according to clinical state during the disease course as: (i) no hospitalization, (ii) hospitalization without oxygen supplementation, (iii) hospitalization with oxygen supplementation by nasal cannula or mask, (iv) intensive care unit (ICU) admission with non-invasive mechanical ventilation, (v) ICU admission with invasive mechanical ventilation or (vi) death, and data was analyzed using ordinal logistic regression.

Results

We included 413 (258 unvaccinated and 155 vaccinated) patients (81%, female) with a median age of 52 (range: 17–85) years at COVID-19 diagnosis. The rates of hospitalization were (36.4% vs. 14.2%), need for any supplemental oxygen (29.5% vs. 9%) and mortality (7% vs. 0.6%) in unvaccinated and vaccinated AIH patients with COVID-19. Having received at least one dose of SARS-CoV-2 vaccine was associated with a significantly lower risk of worse COVID-19 severity, after adjusting for age, sex, comorbidities and presence of cirrhosis (adjusted odds ratio [aOR] 0.18, 95% confidence interval [CI], 0.10–0.31). Overall, vaccination against SARS-CoV-2 was associated with a significantly lower risk of mortality from COVID-19 (aOR 0.20, 95% CI 0.11–0.35).

Conclusions

SARS-CoV-2 vaccination significantly reduced the risk of COVID-19 severity and mortality in patients with AIH.

Predicting portal thrombosis in cirrhosis: A prospective study of clinical, ultrasonographic and hemostatic factors

BACKGROUND & AIMS

Portal vein thrombosis (PVT) is a relatively frequent event in patients with cirrhosis. While different risk factors for PVT have been reported, such as decreased portal blood flow velocity (PBFV) and parameters related with severity of portal hypertension, these are based on retrospective studies assessing only a discrete number of parameters. The aim of the current study was to evaluate the incidence and risks factors for non-tumoral PVT development in a large prospective cohort of patients with cirrhosis.

METHODS

We performed an exhaustive evaluation of clinical, biochemical, inflammatory and acquired/hereditary hemostatic profiles in 369 patients with cirrhosis without PVT who were prospectively followed-up. Doppler ultrasound was performed at baseline and every 6 months or whenever clinically indicated. PVT development was always confirmed by computed tomography.

RESULTS

Twenty-nine patients developed non-tumoral PVT, with an incidence of 1.6%, 6% and 8.4% at 1, 3 and 5 years, respectively. Low platelet count, PBFV <15 cm/sec and history of variceal bleeding were factors independently associated with a high PVT risk. No relationship between PVT development and any other clinical biochemical, inflammatory and acquired or hereditary hemostatic parameter was found.

CONCLUSIONS

In patients with cirrhosis, the factors predictive of PVT development were mainly those related to the severity of portal hypertension. Our results do not support the role of hemostatic alterations (inherited or acquired) and inflammatory markers in the prediction of PVT in patients with cirrhosis.

LAY SUMMARY

Patients with cirrhosis and more severe portal hypertension are at higher risk of non-tumoral portal vein thrombosis development. Acquired or inherited hemostatic disorders, as well as inflammatory status, do not seem to predict the development of portal vein thrombosis in patients with cirrhosis.

Effects of Early Placement of Transjugular Portosystemic Shunts in Patients With High-Risk Acute Variceal Bleeding: a Meta-analysis of Individual Patient Data

BACKGROUND & AIMS

Compared with drugs plus endoscopy, placement of transjugular portosystemic shunt within 72 hours of admission to the hospital (early or preventive transjugular intrahepatic portosystemic shunt [TIPS], also called preemptive TIPS) increases the proportion of high-risk patients with cirrhosis and acute variceal bleeding who survive for 1 year. However, the benefit of preemptive TIPS is less clear for patients with a Child-Pugh score of B and active bleeding (CP-B+AB). We performed an individual data meta-analysis to assess the efficacy of preemptive TIPS in these patients and identify factors associated with reduced survival of patients receiving preemptive TIPS.

METHODS

We searched publication databases for randomized controlled trials and observational studies comparing the effects of preemptive TIPS versus endoscopy plus nonselective beta-blockers in the specific population of high-risk patients with cirrhosis and acute variceal bleeding (CP-B+AB or Child-Pugh C, below 14 points), through December 31, 2019. We performed a meta-analysis of data from 7 studies (3 randomized controlled trials and 4 observational studies), comprising 1327 patients (310 received preemptive TIPS and 1017 received drugs plus endoscopy). We built adjusted models to evaluate risk using propensity score for baseline covariates. Multivariate Cox regression models were used to assess the factors associated with survival time. The primary endpoint was effects of preemptive TIPS versus drugs plus endoscopy on 1-year survival in the overall population as well as CP-B+AB and Child-Pugh C patients.

RESULTS

Overall, preemptive TIPS significantly increased the proportion of high-risk patients with cirrhosis and acute variceal bleeding who survived for 1 year, compared with drugs plus endoscopy (hazard ratio [HR] 0.443; 95% CI 0.323-0.607; P < .001). This effect was observed in CP-B+AB patients (HR 0.524; 95% CI 0.307-0.896; P = .018) and in patients with Child-Pugh C scores below 14 points (HR 0.374; 95% CI 0.253-0.553; P < .001). Preemptive TIPS significantly improved control of bleeding and ascites without increasing risk of hepatic encephalopathy in Child-Pugh C and CP-B+AB patients, compared with drugs plus endoscopy. Cox analysis of patients who received preemptive TIPS showed that patients could be classified into 3 categories for risk of death, based on age, serum level of creatinine, and Child-Pugh score. In each of these risk categories, preemptive TIPS increased the proportion of patients who survived for 1 year, compared with drugs plus endoscopy.

CONCLUSIONS

In a meta-analysis of data from 1327 patients with cirrhosis, acute variceal bleeding, and Child-Pugh score between 10 and 13 points or CP-B+AB, preemptive TIPS increased the proportion who survived for 1 year, in both subgroups separately, compared with drugs plus endoscopy.

Wetting a superomniphobic porous system

While important research has been focused on developing surfaces that do not wet, some textures with high-wetting resistance are familiar in other applications in which the opposite is needed. A multivalued surface, common in most fabrics or meshes, allows the invading gas-liquid interface to support relatively high imposed pressures and plays a key role in producing topographic elements that avoid wetting. Here we study experimentally and theoretically the critical pressure needed to move a liquid through a network of pores and show that, for small aperture size, wetting and leaking are typical first-order transitions, with a singular behavior at the omniphobic/omniphilic limit (θc = π/2).

Porous Nanogold/Polyurethane Scaffolds with Improved Antibiofilm, Mechanical, and Thermal Properties and with Reduced Effects on Cell Viability: A Suitable Material for Soft Tissue Applications

The use of implants carries on a series of problems, among them infections, poor biocompatibility, high levels of cytotoxicity, and significant mechanical differences between implants and host organs that promote stress shielding effects. These problems indicate that the materials used to make implants must meet essential requirements and high standards for implantations to be successful. In this work, we present the synthesis, characterization and evaluation of the antibiofilm, mechanical, and thermal properties, and cytotoxic effect of a nanocomposite-based scaffold on polyurethane (PU) and gold nanoparticles (AuNPs) for soft tissue applications. The effect of the quantity of AuNPs on the antibacterial activity of nanocomposite scaffolds was evaluated against Staphylococcus epidermidis and Klebsiella spp., with a resulting 99.99% inhibition of both bacteria using a small quantity of nanoparticles. Cytotoxicity was evaluated with the T10 1/2 test against fibroblast cells. The results demonstrated that porous nanogold/PU scaffolds have no toxic effects on fibroblast cells to the 5 day exposition. With respect to mechanical properties, stress-strain curves showed that the compressive modulus and yield strength of PU scaffolds were significantly enhanced by AuNPs (by at least 10 times). This is due to changes in the arrangement of hard segments of PU, which increase the stiffness of the polymer. Thermogravimetric analysis showed that the degradation onset temperature rises with an increase in the quantity of AuNPs. These properties and characteristics demonstrate that porous nanogold/PU scaffolds are suitable material for use in soft tissue implants.

Timing Affects Measurement of Portal Pressure Gradient After Placement of Transjugular Intrahepatic Portosystemic Shunts in Patients With Portal Hypertension

BACKGROUND & AIMS

A reduction in portal pressure gradient (PPG) to <12 mm Hg after placement of a transjugular intrahepatic portosystemic shunt (TIPS) correlates with the absence of further bleeding or ascites at follow-up examinations of patients with cirrhosis. The PPG is usually measured immediately after placement of the TIPS, when different circumstances can affect PPG values, which could affect determination of risk for decompensation. We investigated variations in PPG measurements collected at different time points after TIPS, aiming to identify a time point after which PPG values were best maintained.

METHODS

We performed a retrospective study of 155 consecutive patients with severe complications of portal hypertension who received placement of TIPS from January 2008 through October 2015; patients were followed until March 2016. We compared PPG values measured at different time points and under different conditions: immediately after placement of TIPS (immediate PPG); at least 24 hours after placement to TIPS into hemodynamically stable patients, without sedation (early PPG); and again 1 month after TIPS placement (late PPG).

RESULTS

The immediate PPG differed significantly from the early PPG, regardless of whether the TIPS was placed using general anesthesia (8.5 ± 3.5 mm Hg vs 10 ± 3.5 mm Hg; P = .015) or deep sedation (12 ± 4 mm Hg vs 10.5 ± 4 mm Hg; P <.001). In considering the 12 mm Hg threshold, concordance between immediate PPG and early PPG values was poor. However, there was no significant difference between mean early PPG and late PPG values (8.5 ± 2.5 mm Hg vs 8 ± 3 mm Hg), or between proportions of patients with early PPG vs late PPG values <12 mm Hg threshold. Maintenance of a PPG value <12 mm Hg during the follow-up period was associated with a lower risk of recurrent or de novo variceal bleeding or ascites (hazard ratio, 0.11; 95% confidence interval, 0.04 0.27; P < .001).

CONCLUSIONS

In a retrospective study of patients with PPG values measured at different time points after TIPS placement, we found measurements of PPG in awake, hemodynamically stable patients at least 24 hours after TIPS to be the best maintained values. Our findings support the concept that PPG value <12 mm Hg after TIPS placement is associated with reduced risk of bleeding and ascites.

Transition from isometric to stretching ridges in thin elastic films

Isometric deformations in thin elastic films easily form ridges to connect large flat regions or facets. Depending on the forces applied or the boundary conditions imposed, these ridges can be isometric, with no stretching or "stretching ridges" when bending and stretching are required to relax the elastic energy. Here we study a simple configuration to observe the transition between an isometric ridge to the well-known stretching ridge observed in crumpled films, and obtain the parameters that determine the ridge type. Specifically, we show that the transversal size of a stretching ridge acts as a cutoff length scale: a ridge is isometric if its width is greater than this characteristic length.

Capillary deformations of bendable films

We address the partial wetting of liquid drops on ultrathin solid sheets resting on a deformable foundation. Considering the membrane limit of sheets that can relax compression through wrinkling at negligible energetic cost, we revisit the classical theory for the contact of liquid drops on solids. Our calculations and experiments show that the liquid-solid-vapor contact angle is modified from the Young angle, even though the elastic bulk modulus (E) of the sheet is so large that the ratio between the surface tension γ and E is of molecular size. This finding indicates a new elastocapillary phenomenon that stems from the high bendability of very thin elastic sheets rather than from material softness. We also show that the size of the wrinkle pattern that emerges in the sheet is fully predictable, thus resolving a puzzle in modeling "drop-on-a-floating-sheet" experiments and enabling a quantitative, calibration-free use of this setup for the metrology of ultrathin films.

Nonperturbative model for wrinkling in highly bendable sheets

The wrinkled geometry of thin films is known to vary appreciably as the applied stresses exceed their buckling threshold. Here we derive and analyze a minimal, nonperturbative set of equations that captures the continuous evolution of radial wrinkles in the simplest axisymmetric geometry from threshold to the far-from-threshold limit, where the compressive stress collapses. This description of the growth of wrinkles is different from the traditional post-buckling approach and is expected to be valid for highly bendable sheets. Numerical analysis of our model predicts two surprising results. First, the number of wrinkles scales anomalously with the thickness of the sheet and the exerted load, in apparent contradiction with previous predictions. Second, there exists an invariant quantity that characterizes the mutual variation of the amplitude and number of wrinkles from threshold to the far-from-threshold regime.

Inertial lubrication theory

Thin fluid films can have surprising behavior depending on the boundary conditions enforced, the energy input and the specific Reynolds number of the fluid motion. Here we study the equations of motion for a thin fluid film with a free boundary and its other interface in contact with a solid wall. Although shear dissipation increases for thinner layers and the motion can generally be described in the limit as viscous, inertial modes can always be excited for a sufficiently high input of energy. We derive the minimal set of equations containing inertial effects in this strongly dissipative regime.

Effect of interactions on vortices in a nonequilibrium polariton condensate

We demonstrate the creation of vortices in a macroscopically occupied polariton state formed in a semiconductor microcavity. A weak external laser beam carrying orbital angular momentum (OAM) is used to imprint a vortex on the condensate arising from the polariton optical parametric oscillator (OPO). The vortex core radius is found to decrease with increasing pump power, and is determined by polariton-polariton interactions. As a result of OAM conservation in the parametric scattering process, the excitation consists of a vortex in the signal and a corresponding antivortex in the idler of the OPO. The experimental results are in good agreement with a theoretical model of a vortex in the polariton OPO.

Multiple coiling of an elastic sheet in a tube

A piece of paper coiled up in a tube hugs the wall in order to minimize its elastic energy. However, a moment's observation shows that the paper fails to make complete contact near its ends. Here, we show that the detached region in the inner part of the coil touches down the tube wall in an angle that is independent of the system size, thickness and stiffness of the surface. This angle is universal for any coiled sheet whose unstressed state is initially flat. Our results show how the shape and stress distribution for this detached region define the geometry and mechanical equilibrium for the rest of the sheet. In particular, we find scaling relations to describe the structure of the outer part of the coil, in contact with the tube wall, as a function of the number of times the sheet is coiled, N .

Universal and nonuniversal features in a model of city traffic

The complex behavior that occurs when traffic lights are synchronized is studied. Two strategies are considered: all lights in phase, and a "green wave" with a propagating green signal. It is found that traffic variables such as traveling time, velocity, and fuel consumption, near resonance, follow critical scaling laws. For the green wave, it is shown that time and velocity scaling laws hold even for random separation between traffic lights. These results suggest the concept of transient resonances, which can be induced by adaptively changing the phase of traffic lights. This may be important to consider when designing strategies for traffic control in cities, where short trajectories, and thus transient solutions, are likely to be relevant.

Mechanics of scars

When a wound heals, as everyone has observed, it contracts, thickens and wrinkles the neighbouring skin, forming a scar. The morphology of the scar depends on the type of wound; an urgent tracheotomy leads to a very different scar than a carefully planned face lift. The surgical challenges of intrusive procedures such as removal of skin lesions, skin transplantation or grafting, and scar removal are complicated by the complex geometry and stress states in different parts of the body. We show that, for relatively general conditions, the nature of the localisation of the scar is determined by the background tension of the skin which can arrest the formation of wrinkles around a scar. Our physical experiments to simulate this procedure indicate that the region deformed by the defect has a characteristic length scale r* approximately 1 square root of tau, where tau is the natural tension of the skin.

Confined developable elastic surfaces: cylinders, cones and the Elastica

We consider two of the simplest problems associated with the packing of a naturally flat thin elastic sheet. Both problems involve packing the sheet into a hollow cylinder; the first considers the partial contact of a cylindrically curved sheet with a cylindrical surface, while the second considers the partial contact of a conically curved sheet with the edge of a cylindrical surface. In each case, we solve the free–boundary problems to determine the shape, response and stability of the confined surfaces. In particular, we show that an exact description of both the cylindrical and conical structures is given by solutions of the Elastica equation, allowing us to present a unified description of a large class of elastic developable surfaces. This includes what is possibly the simplest example of strain localization, occurring at a point and forming one of the constituent elements of a crumpled elastic sheet.

The elements of draping

We consider the gravity-induced draping of a 3D object with a naturally flat, isotropic elastic sheet. As the size of the sheet increases, we observe the appearance of new folded structures of increasing complexity that arise because of the competition between elasticity and gravity. We analyze some of the simpler 3D structures by determining their shape and analyzing their response and stability and show that these structures can easily switch between a number of metastable configurations. For more complex draperies, we derive scaling laws for the appearance and disappearance of new length scales. Our results are consistent with commonplace observations of drapes and complement large-scale computations of draping by providing benchmarks. They also yield a qualitative guide to fashion design and virtual reality animation.

Geometry and physics of wrinkling

The wrinkling of thin elastic sheets occurs over a range of length scales, from the fine scale patterns in substrates on which cells crawl to the coarse wrinkles seen in clothes. Motivated by the wrinkling of a stretched elastic sheet, we deduce a general theory of wrinkling, valid far from the onset of the instability, using elementary geometry and the physics of bending and stretching. Our main result is a set of simple scaling laws; the wavelength of the wrinkles lambda approximately K(-1/4), where K is the stiffness due to an "elastic substrate" effect with a multitude of origins, and the amplitude of the wrinkle A approximately lambda. These could form the basis of a highly sensitive quantitative wrinkling assay for the mechanical characterization of thin solid membranes.

[Cefotaxime, twenty years later. Observational study in critically ill patients]

OBJECTIVE

Afer twenty years of commercial availability of cefotaxime, the objective of this study was to know the reasons and modes of use, administration dosage as well as its effectiveness and tolerance in critically ill patients admitted to Intensive Care Units (ICU) in our country.

DESIGN

Open, prospective, observational, multicenter study.

SUBJECTS

All patients who had cefotaxime administered in monotherapy or in combination with other antibiotics were included as cases in this study.

RESULTS

A total of 624 patients were included in 44 ICUs (average 14 cases). Cefotaxime was indicated for therapy of 274 community-acquired infections (43.9%), 194 prophylaxis (31.1%), and 156 nosocomial infections (25.0%). Both community-acquired pneumonia (149, 34.7%) and mechanical ventilation associated pneumonia (62, 14.4%) predominated, followed by trachebronchitis (60, 13.9%) and central nervous system infections (42, 9.8%). Over half of infections (222, 51.6%) presented as systemic inflammatory response syndrome (SIRS), 133 (30.9%) as severe sepsis, and 75 (17.4%) as septic shock. In 374 (87.0%) out of the 430 cases of infection treatment, cefotaxime wan prescribed on an empirical basis and in 150 of them (40.1%) a further confirmation of the causative agent was obtained. In 120 (27.9%) cases, cefotaxime was administered as monotherapy and in the remaining cases in association with one or more antibiotics.The use of cefotaxime as prophylaxis was evaluated as failure in 31 (16.0%) of the cases, whereas in treatment it was considered as failure in 98 (22.8%) of the 430 cases, 51 community-acquired infections, 27 (27.3%) of ICU-acquired infections, and 20 (35.1%) nosocomial infections acquired outside the ICU. In 127 (29.5%) of the 430 infection treatments the initial treatment was changed. The reasons for the change included clinical failure (36, 28.3%), recovery of an uncovered pathogen with the antibiotic (40, 31.5%), emergence of multi-resistant pathogens (28, 22.0%), to decrease the therapeutic spectrum (7, 5.5%), and other reasons (16). Cefotoxime was also changed in 21 (6.0%) of the 194 cases in which it was used as prophylaxis. In 32 (5.1%) patients 37 adverse effects were noted which were associated with a possible or likely use of cefotaxime. Most notably, diarrhoea in 15 (2.4%) occasions and skin rash in 6 cases (1.0%).

CONCLUSIONS

Cefotaxime is still one of the therapies of choice for community-acquired and nosocomial infections as well as in different prophylactic modes. It is mostly used on an empirical basis and associated with other antibiotics. Clinical and microbiological efficiency is high whereas adverse effects related to its use have been scarce.

Hemodynamic effects of oxygen therapy in patients with acute exacerbations of chronic obstructive pulmonary disease

The effects of oxygen therapy in patients with stable COPD have been previously reported; however, the hemodynamic changes induced by oxygen therapy in patients during acute exacerbations of COPD are less well known. To investigate the hemodynamic effects of controlled oxygen therapy in patients with acute exacerbations of COPD shortly after arriving at the hospital, we studied 15 consecutive patients who came to the emergency room with acutely decompensated COPD that did not require mechanical ventilation. Patients were monitored with a pulmonary artery catheter and a radial artery catheter. Oxygen uptake was calculated by the modified Fick equation. Arterial and venous blood gas levels and hemodynamic parameters were measured while breathing room air (baseline) and after 30 min on oxygen therapy via face mask. Measurements were repeated after 24 and 48 h. The fractional concentration of oxygen in the inspired gas (FIO2) administered was adjusted to keep the PaO2 above 55 mm Hg. All patients had a PaO2 below 45 mm Hg at the beginning of the study. After 30 min of oxygen therapy, there was a significant (p < 0.05) increase in arterial oxygen saturation (from 62 +/- 16 to 87 +/- 9 percent), mixed-venous oxygen pressure (from 25 +/- 5 to 43 +/- 11 mm Hg), and oxygen delivery (from 11.1 +/- 3.7 to 19.3 +/- 8.9 ml/kg.min). Oxygen uptake did not change significantly (from 4.1 +/- 1.2 to 4.3 +/- 1.6 ml/kg.min). The oxygen extraction ratio decreased from 37.5 +/- 10.1 to 25.3 +/- 9.6 percent. These changes were maintained during the following 48 h. There were no significant changes in cardiac output and systemic vascular resistance. A trend toward lower values of pulmonary vascular resistance did not reach statistical significance. We conclude that oxygen therapy in patients with acute exacerbations of COPD that do not require mechanical ventilation increases oxygen delivery without changes in cardiac output or oxygen uptake.

Bronchodilators in patients with chronic obstructive pulmonary disease on mechanical ventilation. Utilization of metered-dose inhalers

Bronchodilators are used widely in the acute exacerbations of chronic obstructive pulmonary disease (COPD), although their effectiveness is not clearly established. We used three bronchodilators in 20 patients with COPD who were being mechanically ventilated. Two of the bronchodilators, ipratropium bromide and salbutamol, were administered from metered-dose inhalers (MDI) through an adapter to the endotracheal tube, and the third, aminophylline, was administered in the form of intravenous infusion. Before administering each drug, peak airway pressure, end-inspiratory pressure, resistive pressure, and auto positive end-expiratory pressure (auto-PEEP) were measured, and inspiratory resistance (Rins) and compliance were calculated. Heart rate (HR) and blood pressure were also recorded, and arterial pH and blood gas determinations were made. These measurements were repeated 60 min after the administration of aminophylline, 15 and 60 min after administering salbutamol, and 30 and 60 min after administering ipratropium bromide. With these three drugs, airway pressures were reduced, as well as auto-PEEP and Rins, with respect to basal values (p less than 0.05). The changes in compliance were only significant with salbutamol (p less than 0.05). HR was only significantly modified with aminophylline (p less than 0.05). No blood gas change was observed with any of the three drugs. It can be concluded that: (1) the three drugs used in this study were equally effective in producing significant bronchodilation in patients on mechanical ventilation for severe acute exacerbation of COPD; (2) the administration of bronchodilators by MDI in intubated patients through a special adapter was as effective as the intravenous administration of aminophylline.