During one-lung ventilation, the nonventilated lung is excluded from the ventilation, with all tidal volume directed into the ventilated lung. This technique facilitates viewing of intrathoracic structures, thereby providing optimal surgical conditions. However, this procedure has been associated with reduced arterial oxygen tension, principally in patients with a previous history of lung disease, since it reduces the surface area available for gas exchange and causes a loss of normal autonomic respiratory regulation. Therefore, maintaining sufficient oxygenation and elimination of carbon dioxide is the greatest challenge in the management of the one-lung ventilation. It is recommend that the tidal volume administrated to the ventilated lung be similar to that used during conventional mechanical ventilation and that high fractions of inspired oxygen be used. However, several alternative methods have been proposed in order to minimize hypoxemia during one-lung ventilation, including the correct positioning of the double-lumen tube, the use of positive end-expiratory pressure or continuous positive airway pressure, nitric oxide administration, and alveolar recruitment. The management of one-lung ventilation continues to be a challenge in clinical practice.

Keywords: tidal volume, hypoxemia, ventilatory management, mechanical ventilation

The physiopathology of obstructive sleep apnea syndrome is multifactorial. Gender and obesity status, as well as genetic, anatomic, and hormonal factors, together with ventilatory drive, interact in a diverse manner in the physiopathology and clinical expression of the disease. Obesity is the main risk factor, since increases in body mass index, visceral fat, and neck circumference are strong predictors of the disease. Progesterone increases the activity of the upper airway dilator muscles and therefore plays a protective role in premenopausal women. This explains the fact that the prevalence of the disease is higher in postmenopausal patients, in patients with polycystic ovary syndrome, as well as in males. Evidence supports the fact that, as individuals grow older, there is a decrease in muscle tonus, with a consequent reduction in the dimensions of the upper airway lumen. Craniofacial anomalies, such as in retrognathia or micrognathia, are accompanied by posterior positioning of the tongue and can result in narrowing of the upper airway lumen. Finally, decreased ventilatory drive has been detected in patients with obstructive sleep apnea syndrome and hypercapnia.

Keywords: Sleep apnea obstructive/physiopathology; Body mass index; Obesity

Objective: To evaluate the frequency of the use of sputum examination in the clinical management of community-acquired pneumonia (CAP) in a general hospital and to determine whether its use has an impact on mortality. Methods: The medical records of CAP patients treated as inpatients between May and November of 2004 at the Nossa Senhora da Conceição Hospital, located in Porto Alegre, Brazil, were reviewed regarding the following aspects: age; gender; severity of pneumonia (Fine score); presence of sputum; sputum bacteriology; treatment history; change in treatment; and mortality. Results: A total of 274 CAP patients (134 males and 140 females) were evaluated. Using the Fine score to quantify severity, we classified 79 (28.8%) of those 274 patients as class II, 45 (16.4%) as class III, 97 (35.4%) as class IV, and 53 (19.3%) as class V. Sputum examination was carried out in 92 patients (33.6%). A valid sample was obtained in 37 cases (13.5%), and an etiological diagnosis was obtained in 26 (9.5%), resulting in a change of treatment in only 9 cases (3.3%). Overall mortality was 18.6%. Advanced age (above 65), CAP severity, and dry cough were associated with an increase in the mortality rate. Sputum examination did not alter any clinical outcome or have any influence on mortality. Conclusion: Sputum examination was used in a minority of patients and was not associated with any noticeable benefit in the clinical management of patients with CAP treated in a hospital setting.

Keywords: Pneumonia/etiology; Sputum; Diagnosis.

Objective: To evaluate the effects that passive cycling exercise, in combination with conventional physical therapy, have on peripheral muscle strength, duration of mechanical ventilation, and length of hospital stay in critically ill patients admitted to the ICU of a tertiary care university hospital. Methods: This was a randomized clinical trial involving 38 patients (≥ 18 years of age) on mechanical ventilation who were randomly divided into two groups: control (n = 16), receiving conventional physical therapy; and intervention (n = 22), receiving conventional physical therapy and engaging in passive cycling exercise five days per week. The mean age of the patients was 46.42 ± 16.25 years, and 23 were male. The outcomes studied were peripheral muscle strength, as measured by the Medical Research Council scale, duration of mechanical ventilation, and length of hospital stay. Results: There was a significant increase in peripheral muscle strength (baseline vs. final) in both groups (control: 40.81 ± 7.68 vs. 45.00 ± 6.89; and intervention: 38.73 ± 11.11 vs. 47.18 ± 8.75; p < 0.001 for both). However, the range of increase in strength was higher in the intervention group than in the control group (8.45 ± 5.20 vs. 4.18 ± 2.63; p = 0.005). There were no significant differences between the groups in terms of duration of mechanical ventilation or length of hospital stay. Conclusions: The results suggest that the performance of continuous passive mobilization on a cyclical basis helps to recover peripheral muscle strength in ICU patients. (ClinicalTrials.gov Identifier: NCT01769846 [http://www.clinicaltrials.gov/])

Keywords: Physical therapy modalities; Intensive care units; Early ambulation; Muscle strength.

Objective: To compare 28-day mortality rates and clinical outcomes in ICU patients with ventilator-associated pneumonia according to the diagnostic strategy used. Methods: This was a prospective randomized clinical trial. Of the 73 patients included in the study, 36 and 37 were randomized to undergo BAL or endotracheal aspiration (EA), respectively. Antibiotic therapy was based on guidelines and was adjusted according to the results of quantitative cultures. Results: The 28-day mortality rate was similar in the BAL and EA groups (25.0% and 37.8%, respectively; p = 0.353). There were no differences between the groups regarding the duration of mechanical ventilation, antibiotic therapy, secondary complications, VAP recurrence, or length of ICU and hospital stay. Initial antibiotic therapy was deemed appropriate in 28 (77.8%) and 30 (83.3%) of the patients in the BAL and EA groups, respectively (p = 0.551). The 28-day mortality rate was not associated with the appropriateness of initial therapy in the BAL and EA groups (appropriate therapy: 35.7% vs. 43.3%; p = 0.553; and inappropriate therapy: 62.5% vs. 50.0%; p = 1.000). Previous use of antibiotics did not affect the culture yield in the EA or BAL group (p = 0.130 and p = 0.484, respectively). Conclusions: In the context of this study, the management of VAP patients, based on the results of quantitative endotracheal aspirate cultures, led to similar clinical outcomes to those obtained with the results of quantitative BAL fluid cultures. (Brazilian Registry of Clinical Trials - ReBEC; identification number RBR-86DCDX [http://www.ensaiosclinicos.gov.br])

Keywords: Bronchoalveolar lavage fluid/diagnosis; Respiratory aspiration; Pneumonia, ventilator-associated.

Tobacco use is the leading preventable cause of death in most countries, including Brazil. Smoking cessation is an important strategy for reducing the morbidity and mortality associated with tobacco-related diseases. An inverse relationship between nicotine use and body weight has been reported, in which body weight tends to be lower among smokers than among nonsmokers. Smoking abstinence results in an increase in body weight for both males and females. On average, sustained quitters gain from 5 to 6 kg, although approximately 10% gain more than 10 kg. Pharmacological treatment for smoking cessation attenuates weight gain. The importance of smoking cessation as a contributing cause of the current obesity epidemic has been little studied. In the USA, the rate of obesity attributable to smoking cessation has been estimated at approximately 6.0% and 3.2% for males and females, respectively. Although the mechanisms are unclear, there is evidence that dopamine and serotonin are appetite suppressants. The administration of nicotine, regardless of the delivery system, acutely raises the levels of these neurotransmitters in the brain, reducing the need for energy intake and consequently suppressing appetite. In addition, nicotine has a direct effect on adipose tissue metabolism, influencing the rate of weight gain following smoking cessation. Leptin, ghrelin and neuropeptide Y are substances that might constitute factors involved in the inverse relationship between nicotine and body mass index, although their roles as determinants or consequences of this relationship have yet to be determined.

Keywords: Smoking; Body weight changes; Nicotine; Body mass index; Leptin; Peptide hormones/ghrelin.

Background: There is a wide variability in clinical practice for treating acute asthma (AA) in the emergency room (ER) interfering in the quality of management. Objective: To evaluate the impact of a clinical protocol for care of acute asthma in the ER of the Hospital de Clínicas de Porto Alegre. Method: In this hospital a cross-sectional study was conducted before and after implementation of the protocol, of consecutive patients presenting with acute asthma in the adult ER (age ³ 12 years). The intention was to measure the effect of recommendations on the objective assessment of severity, utilization of diagnostic tools, proposed therapy, not recommended therapy and on the outcomes. Results: The pre-protocol group comprised 108 patients and the protocol group comprised 96 patients. There was a significant increase in the use of pulse oximetry (8% to 77%, p<0.001) and PEFR (5% to 21%, p<0.001). There was an increase in the utilization of radiology (33% to 66%, p<0.001) and in that of blood tests (11% to 25%, p=0.016). There was also an increase in the number of patients receiving the three recommended nebulizations in the first hour (22% to 36%, p=0.04). Although the overall use of corticosteroids did not change, there was a significant increase in the use of oral steroids (8% to 28%, p<0.001). There was no significant difference in the not recommended therapy, time of stay and outcomes. Conclusion: The acute asthma clinical protocol used in the ER was associated to a positive effect on the objective assessment of severity of asthma and on the use of the recommended therapy. No other significant influence on the treatment or on the outcome was perceived.

Keywords: Clinical protocols. Asthma. Emergency medicine.

Objective: The use of the rapid shallow breathing index (RSBI) is recommended in ICUs, where it is used as a predictor of mechanical ventilation (MV) weaning success. The aim of this study was to compare the performance of the RSBI calculated by the traditional method (described in 1991) with that of the RSBI calculated directly from MV parameters. Methods: This was a prospective observational study involving patients who had been on MV for more than 24 h and were candidates for weaning. The RSBI was obtained by the same examiner using the two different methods (employing a spirometer and the parameters from the ventilator display) at random. In comparing the values obtained with the two methods, we used the Mann-Whitney test, Pearson's linear correlation test, and Bland-Altman plots. The performance of the methods was compared by evaluation of the areas under the ROC curves. Results: Of the 109 selected patients (60 males; mean age, 62 ± 20 years), 65 were successfully weaned, and 36 died. There were statistically significant differences between the two methods for respiratory rate, tidal volume, and RSBI (p < 0.001 for all). However, when the two methods were compared, the concordance and the intra-observer variation coefficient were 0.94 (0.92-0.96) and 11.16%, respectively. The area under the ROC curve was similar for both methods (0.81 ± 0.04 vs. 0.82 ± 0.04; p = 0.935), which is relevant in the context of this study. Conclusions: The satisfactory performance of the RSBI as a predictor of weaning success, regardless of the method employed, demonstrates the utility of the method using the mechanical ventilator.

Keywords: Respiration, artificial; Ventilator weaning; Spirometry.

Objective: Failure of noninvasive ventilation (NIV) has been associated with short-term adverse effects related to the use of masks. The aim of this study was to compare the incidence, type and intensity of adverse effects, as well as the comfort, of total face masks (TFMs), facial masks (FMs) and nasal masks (NMs) during NIV. Methods: This was a randomized crossover trial involving 24 healthy volunteers submitted to six sessions of NIV in bilevel positive airway pressure mode using the TFM, FM and NM masks at low and moderate-to-high pressure levels. A written questionnaire was applied in order to evaluate eleven specific adverse effects related to the use of the masks. Comfort was assessed using a visual analog scale. The CO2 exhaled into the ventilator circuit was measured between the mask and the exhalation port. Results: The performance of the TFM was similar to that of the NM and FM in terms of comfort scores. Higher pressure levels reduced comfort and increased adverse effects, regardless of the mask type. When the TFM was used, there were fewer air leaks and less pain at the nose bridge, although there was greater oronasal dryness and claustrophobia. Air leaks were most pronounced when the FM was used. The partial pressure of exhaled CO2 entering the ventilator circuit was zero for the TFM. Conclusions: The short-term adverse effects caused by NIV interfaces are related to mask type and pressure settings. The TFM is a reliable alternative to the NM and FM. Rebreathing of CO2 from the circuit is less likely to occur when a TFM is used.

Keywords: Intermittent positive-pressure ventilation; Masks/adverse effects; Respiratory insufficiency;Equipment failure analysis.

Objective: To determine the occurrence of cardiorespiratory alterations and to identify adverse events during the intrahospital transport of patients on invasive ventilation. Methods: A prospective observational non-randomized study was conducted at two tertiary hospitals between April of 2005 and December of 2006. We included patients on invasive ventilation who required intrahospital transport during the study period. Exclusion criteria were as follows: being under suspicion of brain death; being submitted to alternate periods of mechanical ventilation/nebulization via a T-piece; and being transported to the operating room. Prior to and after transport, we evaluated blood gas analysis results, vital signs, use of medications by means of a continuous infusion pump, parameters regarding the mechanical ventilator, duration of transport, transport distance and number of professionals involved. Results: We included 48 patients in a total of 58 intrahospital transports. Relevant cardiorespiratory alterations were identified in 39 transports, totaling 86 episodes, as well as 16 adverse events related to equipment or personnel failure, such as problems related to batteries and to miscommunication. Conclusions: During the intrahospital transport of patients on invasive ventilation, cardiorespiratory alterations were common (67.2%), and adverse events occurred in 75.7% of the transports.

Keywords: Patient transfer; Intensive care; Respiration, artificial; Ventilators, mechanical.

Objective: Patients with high cervical spinal cord injury are usually dependent on mechanical ventilation support, which, albeit life saving, is associated with complications and decreased life expectancy because of respiratory infections. Diaphragm pacing stimulation (DPS), sometimes referred to as electric ventilation, induces inhalation by stimulating the inspiratory muscles. Our objective was to highlight the indications for and some aspects of the surgical technique employed in the laparoscopic insertion of the DPS electrodes, as well as to describe five cases of tetraplegic patients submitted to the technique. Methods: Patient selection involved transcutaneous phrenic nerve studies in order to determine whether the phrenic nerves were preserved. The surgical approach was traditional laparoscopy, with four ports. The initial step was electrical mapping in order to locate the "motor points" (the points at which stimulation would cause maximal contraction of the diaphragm). If the diaphragm mapping was successful, four electrodes were implanted into the abdominal surface of the diaphragm, two on each side, to stimulate the branches of the phrenic nerve. Results: Of the five patients, three could breathe using DPS alone for more than 24 h, one could do so for more than 6 h, and one could not do so at all. Conclusions: Although a longer follow-up period is needed in order to reach definitive conclusions, the initial results have been promising. At this writing, most of our patients have been able to remain ventilator-free for long periods of time.

Keywords: Spinal cord injuries; Quadriplegia; Respiration, artificial; Pacemaker, artificial; Diaphragm.

Objective: To develop and apply a competency-based test to assess learning among internal medicine residents during a respiratory ICU rotation at a university hospital. Methods: We developed a test comprising 19 multiple-choice questions regarding knowledge of mechanical ventilation (MV) and 4 self-assessment questions regarding the degree of confidence in the management of MV. The test was applied on the first and last day of a 30-day respiratory ICU rotation (pre-rotation and post-rotation, respectively). During the rotation, the residents had lectures, underwent simulator training, and shadowed physicians on daily bedside rounds focused on teaching MV management. Results: Fifty residents completed the test at both time points. The mean score increased from 6.9 ± 1.2 (pre-rotation) to 8.6 ± 0.8 (post-rotation; p < 0.001). On questions regarding the approach to hypoxemia, the recognition of patient-ventilator asynchrony, and the recognition of risk factors for extubation failure, the post-rotation scores were significantly higher than the pre-rotation scores. Confidence in airway management increased from 6% before the rotation to 22% after the rotation (p = 0.02), whereas confidence in making the initial MV settings increased from 31% to 96% (p < 0.001) and confidence in adjusting the ventilator modes increased from 23% to 77% (p < 0.001). Conclusions: We developed a competency-based test to assess knowledge of MV among residents before and after an rotation in a respiratory ICU. Resident performance increased significantly after the rotation, as did their confidence in caring for patients on MV.

Keywords: Education, medical; Respiration, artificial; Surveys and questionnaires; internship and residency; Competency-based education; Educational measurement.

Objective: To compare the incidence and intensity of acute adverse effects and the variation in the temperature of facial skin by thermography after the use of noninvasive ventilation (NIV). Methods: We included 20 healthy volunteers receiving NIV via oronasal mask for 1 h. The volunteers were randomly divided into two groups according to the ventilatory mode: bilevel positive airway pressure (BiPAP) or continuous positive airway pressure (CPAP). Facial thermography was performed in order to determine the temperature of the face where it was in contact with the mask and of the nasal dorsum at various time points. After removal of the mask, the volunteers completed a questionnaire about adverse effects of NIV. Results: The incidence and intensity of acute adverse effects were higher in the individuals receiving BiPAP than in those receiving CPAP (16.1% vs. 5.6%). Thermographic analysis showed a significant cooling of the facial skin in the two regions of interest immediately after removal of the mask. The more intense acute adverse effects occurred predominantly among the participants in whom the decrease in the mean temperature of the nasal dorsum was lower (14.4% vs. 7.2%). The thermographic visual analysis of the zones of cooling and heating on the face identified areas of hypoperfusion or reactive hyperemia. Conclusions: The use of BiPAP mode was associated with a higher incidence and intensity of NIV-related acute adverse effects. There was an association between acute adverse effects and less cooling of the nasal dorsum immediately after removal of the mask. Cutaneous thermography can be an additional tool to detect adverse effects that the use of NIV has on facial skin.

Keywords: Masks; Noninvasive ventilation; Thermography.