Ventilação de Alta Frequência Oscilatória Exclusiva com Optimização do Volume Pulmonar no Recém-Nascido de Extremo Baixo Peso (Estudo Comparativo com Ventilação de Alta Frequência Oscilatória após Ventilação Convencional)

Objectivo: A Ventilação de Alta Frequência Oscilatória (VAFO) tem ainda poucos anos de utilização em Portugal. Os seus resultados pouco uniformes têm sido relacionados com o tipo de estratégia utilizada. A optimização do volume pulmonar com utilização de uma estratégia de alto volume, tem vindo a definir-se como a estratégia mais eficaz. Considerámos como objectivos prioritários, a avaliação dos benefícios desta técnica na redução da mortalidade e na redução da morbilidade respiratória precoce e tardia, na retinopatia da prematuridade (ROP) e na hemorragia intraperiventricular (HIPV). Doentes e Métodos: Desde 1 de Janeiro de 1999 até 31 de Março de 2000 (15 meses), usámos esta estratégia ventilatória no Recém Nascido de Muito Baixo Peso (RN MBP). Utilizámos VAFO como modalidade ventilatória exclusiva e imediatamente após intubação traqueal ou após chegada do RN à Unidade de Cuidados Intensivos neonatais (UCIN). Iniciámos de imediato a Optimização do Volume Pulmonar (OPT). A administração de surfactante só foi efectuada após critério de pulmão optimizado. Foram ventilados com esta técnica, 154 RN com idade gestacional < 34 semanas com DMH/SDR e necessitando de ventilação mecânica. Destes RN, o grupo com peso de nascimento (PN) < 950 gramas e idade gestacional entre 25-29 semanas (Coorte VAFO/OPT = 36 RN) foi comparado com uma Coorte histórica de VAFO após curto período de ventilação convencional (VC) de 1997-1998 (grupo VC + VAFO = 27 RN). Ambos os grupos tiveram a Doença das Membranas Hialinas(DMH) como diagnóstico primário. Local de Estudo: Unidade de Cuidados Intensivos Neonatais da Maternidade Dr. Alfredo da Costa (12 postos de ventilação permanente). Resultados: Os dois grupos comparados (VAFO/OPT e VC + VAFO) foram semelhantes nos dados demográficos (peso, idade gestacional, sexo), corticoterapia pré-natal e gravidade radiológica da DMH. Apesar da gravidade radiológica de ambos os grupos ser semelhante, o tipo de estratégia ventilatória utilizada no grupo VAFO/OPT, ou seja, a optimização do volume pulmonar, permitiu uma menor administração do surfactante. O tempo de ventilação e o tempo de oxigenação (dias de 02) foi estatisticamente inferior no grupo VAFO/OPT (respectivamente p=0,000 e p=0.003), tal como a HIPV, ROP e mortalidade (respectivamente p=0,0029, p=0,009 e p=0,031). A Doença Pulmonar Crónica (DPC) foi percentualmente bastante inferior neste grupo (p=0,051). Conclusão: A VAFO como modalidade ventilatória exclusiva, iniciada imediatamente após intubação traqueal e/ou chegada do RN à UCIN e com optimização do volume pulmonar, encurtou a necessidade de suporte respiratório e de oxigenação e melhorou a morbilidade pulmonar no RN MBP com DMH.

Ventilação de Alta Frequência Oscilatória como Método Ventilatório Único e Exclusivo e com Estratégia de Optimização do Volume Pulmonar no Recém-Nascido de Muito Baixo Peso

Objectivo: A Ventilação de Alta Frequência Oscilatória(VAFO) tem resultados promissores na ventilação de RN de pré-termo com Doença das Membranas Hialinas (DMH), embora os resultados dos estudos publicados não sejam uniformes. Esta diferença dos resultados poderá ser atribuída à falta de uniformidade das estratégias utilizadas e à forma de utilização desta técnica de ventilação. A utilização de VAFO precoce com optimização precoce do volume pulmonar, tem sido a estratégia mais eficaz, levando a uma menor incidência de morbilidade pulmonar. Considerámos como objectivos prioritários, a avaliação dos benefícios desta técnica na redução da morbilidade respiratória precoce e tardia, na incidência da retinopatia da prematuridade (ROP) e da hemorragia intraperiventricular (HIPV) e na redução da mortalidade. Desenho do Estudo: Estudo descritivo prospectivo. Os Recém-nascidos (RN) foram seguidos periodicamente desde a altura do nascimento até ao momento da alta hospitalar. Local do estudo: Unidade de Cuidados Intensivos Neonatais(UCIRN) da Maternidade Dr. Alfredo da Costa (Unidade Terciária com 12 postos de ventilação permanentes). Doentes: 424 RN com peso de nascimento inferior ou igual a 1500gr (RN MBP), nascidos na Maternidade entre 1 de Janeiro de 1999 e 1 de Janeiro de 2003 (4 anos). O grupo de extremo baixo peso(peso de nascimento < 1000 gr) foi analisado separadamente. Foram excluídos RN com hidrópsia fetal, anomalias congénitas cardíacas, pulmonares ou da parede abdominal (incluindo hérnia diafragmática) e também RN com pneumonia congénita e aqueles nascidos fora da maternidade ("Outborn"). Foram também excluídos RN optimizados mas sem o critério de optimização definido pelo estudo. Métodos: Em todos os RN MBP foi utilizada VAFO como modalidade ventilatória única e exclusiva e imediatamente após intubação traqueal na Unidade de Cuidados Intensivos Neonatais(UCIN) ou após chegada do RN à UCIN vindo da sala de partos ou do bloco operatório. Iniciámos de imediato a Optimização do Volume Pulmonar (OPT). A administração de surfactante só foi efectuada após optimização do volume pulmonar (1°- critério de pulmão optimizado: definido como a CDP (MAP) que permitiu reduzir o Fi02 para valores < 40%, 2°- critérios de administração de surfactante; CDP X Fi02 > 3 - 4, a / A 02 < 0.22 - 0.17 e / ou evidência radiológica de DMH de grau III - IV). A Doença pulmonar Crónica(DPC) foi definida como a necessidade de suplementação com 02 às 36 semanas de idade pós-concepcional. Resultados: O total da população de RN MBP, nascidos na MAC, correspondeu a 424; destes, 57 RN faleceram (13,4%) e 367 sobreviveram (86,5 %). A mediana do peso de nascimento foi de 989 gr e a da idade gestacional de 28 semanas. Dos sobreviventes a mediana do tempo de ventilação e de suplementação com 02 foi respectivamentre de 2,5 dias (min/Max = 6 horas/70 dias) e 23 dias (min / Max = 2 / 130 dias). A incidência de DPC foi de 9.0 % (33 / 367). Nenhum RN teve alta hospitalar submetido a terapêutica com 02. A incidência de HIPV grau III - IV (grupo total de RN) foi de 9.9% (42 / 424) e a de ROP 3 de 7.7% (24 / 310). A população total de extremo baixo peso, nascida na MAC (RN < 1000 gr), correspondeu a 210 RN; 46 faleceram (21.9%), 164 RN sobreviveram(78.1%). Dos sobreviventes a mediana do tempo de ventilação e do tempo de suplementação com 02 foi respectivamente de 5 dias (min/ Max = 12 horas / 70 dias) e de 40 dias (min / Max = 4 / 130 dias). A incidência de DPC foi neste grupo de 15.9% (26 / 164). Nenhum RN teve alta hospitalar submetido a terapêutica com 02. A incidência de HIPV de grau III - IV (grupo total < 1000 gr) foi de 13.8 %(29 / 210) e a de ROP 3 foi de 13.1 % (20 / 153). Conclusão: A VAFO como modalidade ventilatória única e exclusiva, iniciada imediatamente após intubação traqueal e/ou chegada do RN à UCIN e com optimização precoce do volume pulmonar, melhorou as trocas gasosas, encurtou a necessidade do suporte respiratório e do tempo de suplementação com 02 e melhorou a morbilidade pulmonar no RN MBP com DMH.

Critical events in mechanically ventilated patients

Mechanical Ventilation is an artificial way to help a Patient to breathe. This procedure is used to support patients with respiratory diseases however in many cases it can provoke lung damages, Acute Respiratory Diseases or organ failure. With the goal to early detect possible patient breath problems a set of limit values was defined to some variables monitored by the ventilator (Average Ventilation Pressure, Compliance Dynamic, Flow, Peak, Plateau and Support Pressure, Positive end-expiratory pressure, Respiratory Rate) in order to create critical events. A critical event is verified when a patient has a value higher or lower than the normal range defined for a certain period of time. The values were defined after elaborate a literature review and meeting with physicians specialized in the area. This work uses data streaming and intelligent agents to process the values collected in real-time and classify them as critical or not. Real data provided by an Intensive Care Unit were used to design and test the solution. In this study it was possible to understand the importance of introduce critical events for Mechanically Ventilated Patients. In some cases a value is considered critical (can trigger an alarm) however it is a single event (instantaneous) and it has not a clinical significance for the patient. The introduction of critical events which crosses a range of values and a pre-defined duration contributes to improve the decision-making process by decreasing the number of false positives and having a better comprehension of the patient condition.

Volemic status influences the response of plasma atrial natriuretic factor to positive airway pressure.

STUDY OBJECTIVE; To evaluate interactive effects of volemic status and positive end-expiratory pressure (PEEP) on the plasma levels of atrial natriuretic factor (ANF) in assist-controlled mechanical ventilation (MV). DESIGN: Three successive protocols applied in randomized order to each participant. SETTING: Clinical investigation laboratory. PARTICIPANTS: Twenty-one young, healthy adults. INTERVENTIONS: The three protocols were as follows: (1) MV+PEEP, normovolemia; (2) MV+PEEP, hypervolemia; and (3) spontaneous breathing (SB), hypervolemia. In protocols 1 and 2, a preliminary period of SB lasting 2 h was followed by MV alone (0.5 h), MV+20 cm H2O PEEP (1 h), and a recovery period of SB (1.5 h). Hypervolemia was induced by the continuous i.v. infusion of 3 L of 0.9% NaCl in 5 h (protocols 2 and 3). MEASUREMENTS AND RESULTS: Heart rate, BP, and the plasma levels of immunoreactive ANF and catecholamines were measured serially. During hypervolemia, ANF significantly decreased when PEEP was added to MV (protocol 2: from 31.1 +/- 2.7 to 20.7 +/- 1.5 fmol/mL; p < 0.01). This did not occur in normovolemia (protocol 1: from 20.0 +/- to 16.7 +/- 1.2 fmol/mL; p = NS). The different effects of MV+PEEP in normovolemia and hypervolemia were not related to differences in circulating catecholamine levels. CONCLUSIONS: These results demonstrate for the first time (to our knowledge) that volemic status modulates the response of plasma ANF to PEEP in humans. The role of ANF in the water and salt retention induced by MV with PEEP might be limited to hypervolemic conditions.

Closure of large intrathoracic airway defects using extrathoracic muscle flaps.

BACKGROUND: Prospective assessment of pedicled extrathoracic muscle flaps for the closure of large intrathoracic airway defects after noncircumferential resection in situations where an end-to-end reconstruction seemed risky (defects of > 4-cm length, desmoplastic reactions after previous infection or radiochemotherapy). METHODS: From 1996 to 2001, 13 intrathoracic muscle transpositions (6 latissimus dorsi and 7 serratus anterior muscle flaps) were performed to close defects of the intrathoracic airways after noncircumferential resection for tumor (n = 5), large tracheoesophageal fistula (n = 2), delayed tracheal injury (n = 1) and bronchopleural fistula (n = 5). In 2 patients, the extent of the tracheal defect required reinforcement of the reconstruction by use of a rib segment embedded into the muscle flap followed by temporary tracheal stenting. Patient follow-up was by clinical examination bronchoscopy and biopsy, pulmonary function tests, and dynamic virtual bronchoscopy by computed tomographic (CT) scan during inspiration and expiration. RESULTS: The airway defects ranged from 2 x 1 cm to 8 x 4 cm and involved up to 50% of the airway circumference. They were all successfully closed using muscle flaps with no mortality and all patients were extubated within 24 hours. Bronchoscopy revealed epithelialization of the reconstructions without dehiscence, stenosis, or recurrence of fistulas. The flow-volume loop was preserved in all patients and dynamic virtual bronchoscopy revealed no significant difference in the endoluminal cross surface areas of the airway between inspiration and expiration above (45 +/- 21 mm(2)), at the site (76 +/- 23 mm(2)) and below the reconstruction (65 +/- 40 mm(2)). CONCLUSIONS: Intrathoracic airway defects of up to 50% of the circumference may be repaired using extrathoracic muscle flaps when an end-to-end reconstruction is not feasible.

Lung function in idiopathic pulmonary fibrosis--extended analyses of the IFIGENIA trial.

BACKGROUND The randomized placebo-controlled IFIGENIA-trial demonstrated that therapy with high-dose N-acetylcysteine (NAC) given for one year, added to prednisone and azathioprine, significantly ameliorates (i.e. slows down) disease progression in terms of vital capacity (VC) (+9%) and diffusing capacity (DLco) (+24%) in idiopathic pulmonary fibrosis (IPF). To better understand the clinical implications of these findings we performed additional, explorative analyses of the IFGENIA data set. METHODS We analysed effects of NAC on VC, DLco, a composite physiologic index (CPI), and mortality in the 155 study-patients. RESULTS In trial completers the functional indices did not change significantly with NAC, whereas most indices deteriorated with placebo; in non-completers the majority of indices worsened but decline was generally less pronounced in most indices with NAC than with placebo. Most categorical analyses of VC, DLco and CPI also showed favourable changes with NAC. The effects of NAC on VC, DLco and CPI were significantly better if the baseline CPI was 50 points or lower. CONCLUSION This descriptive analysis confirms and extends the favourable effects of NAC on lung function in IPF and emphasizes the usefulness of VC, DLco, and the CPI for the evaluation of a therapeutic effect. Most importantly, less progressed disease as indicated by a CPI of 50 points or lower at baseline was more responsive to therapy in this study.

Alveolar overdistension as a cause of lung injury: differences among three animal species.

This study analyses characteristics of lung injuries produced by alveolar overdistension in three animal species. Mechanical ventilation at normal tidal volume (10 mL/Kg) and high tidal volume (50 mL/Kg) was applied for 30 min in each species. Data were gathered on wet/dry weight ratio, histological score, and area of alveolar collapse. Five out of six rabbits with high tidal volume developed tension pneumothorax, and the rabbit results were therefore not included in the histological analysis. Lungs from the pigs and rats showed minimal histological lesions. Pigs ventilated with high tidal volume had significantly greater oedema, higher neutrophil infiltration, and higher percentage area of alveolar collapse than rats ventilated with high tidal volume. We conclude that rabbits are not an appropriate species for in vivo studies of alveolar overdistension due to their fragility. Although some histological lesions are observed in pigs and rats, the lesions do not appear to be relevant.

Predictors of red blood cell transfusion after cardiac surgery: a prospective cohort study

Abstract OBJECTIVE To identify predictors of red blood cell transfusion (RBCT) after cardiac surgery. METHOD A prospective cohort study performed with 323 adults after cardiac surgery, from April to December of 2013. A data collection instrument was constructed by the researchers containing factors associated with excessive bleeding after cardiac surgery, as found in the literature, for investigation in the immediate postoperative period. The relationship between risk factors and the outcome was assessed by univariate analysis and logistic regression. RESULTS The factors associated with RBCT in the immediate postoperative period included lower height and weight, decreased platelet count, lower hemoglobin level, higher prevalence of platelet count <150x10 3/mm3, lower volume of protamine, longer duration of anesthesia, higher prevalence of intraoperative RBCT, lower body temperature, higher heart rate and higher positive end-expiratory pressure. The independent predictor was weight <66.5Kg. CONCLUSION Factors associated with RBCT in the immediate postoperative period of cardiac surgery were found. The independent predictor was weight.

Neurally adjusted ventilatory assist can improve arterial oxygenation

INTRODUCTION. Neurally Adjusted Ventilatory Assist (NAVA) [1] is a new spontaneousassisted ventilatory mode which uses the diaphragmatic electrical activity (Eadi) to pilot the ventilator. Eadi is used to initiate the ventilator's pressurization and cycling off. Delivered inspiratory assistance is proportional to Eadi. NAVA can improve patient-ventilator synchrony [2] compared to pressure support (PS), but little is known about its effect on minute ventilation and oxygenation. OBJECTIVES. To compare the effects of NAVA and PS on minute ventilation and oxygenation and to analyze potential determinant factors for oxygenation. METHODS. Comparison between two 20-min periods under NAVA and PS. NAVA gain (proportionality factor between Eadi and delivered pressure) set as to obtain the same peak pressure as in PS. FIO2 and positive end-expiratory pressure (PEEP) were the same in NAVA and PS. Blood gas analyses were performed at the end of both recording periods. Statistical analysis: groups were compared with paired t tests or non parametric Wilcoxon signed-rank tests. p\0.05 was considered significant. RESULTS. [Mean ± SD]: 22 patients (age 66 ± 12 year, 7 M/15F, BMI 23.4 ± 3.1 kg/m2), 8 patients with COPD. Initial settings: PS 13 ± 3 cmH2O, PEEP 7 ± 2 cmH2O, NAVA gain 2.2 ± 1.8. Minute ventilation and PaCO2 were the same with both modes (p = 0.296 and 0.848, respectively). Tidal volume was lower with NAVA (427 ± 102 vs. 477 ± 102 ml, p\0.001). In contrast respiratory rate was higher with NAVA (25.6 ± 9.5 vs. 22.3 ± 8.9 cycles/min). Arterial oxygenation was improved with NAVA (PaO2 85.1 ± 28.9 vs. 75.8 ± 11.9 mmHg, p = 0.017, PaO2/FIO2 210 ± 53 vs. 195 ± 58 mmHg, p = 0.019). Neural inspiratory time (Tin) was comparable between NAVA and PS (p = 0.566). Among potential determinant factors for oxygenation, mean airway pressure (Pmean) was lower with NAVA (10.6 ± 2.6 vs. 11.1 ± 2.4 cmH2O, p = 0.006), as was the pressure time product (PTP) (6.8 ± 3.0 vs. 9.2 ± 3.5 cmH2O 9 s, p = 0.004). There were less asynchrony events with NAVA (2.3 ± 2.0 vs. 4.4 ± 3.8, p = 0.009).Tidal volume variability was higher with NAVA (variation coefficient: 30 ± 19.5 vs. 13.5 ± 8.6, p\0.001). Inspiratory time in excess (Tiex) was lower with NAVA (56 ± 23 vs. 202 ± 200 ms, p = 0.001). CONCLUSION. Despite lower Pmean and PTP in NAVA, arterial oxygenation was improved compared to PS. As asynchronies may be associated with an increased work of breathing and a higher oxygen consumption, their decrease in number with NAVA could be an explanation for oxygenation improvement. Another explanation could be the increase in VT variability. Further studies should now be performed to confirm the potential of NAVA in improving arterial oxygenation and explore the underlying mechanisms.

Forced oscillation assessment of respiratory mechanics in ventilated patients

The forced oscillation technique (FOT) is a method for non-invasively assessing respiratory mechanics that is applicable both in paralysed and non-paralysed patients. As the FOT requires a minimal modification of the conventional ventilation setting and does not interfere with the ventilation protocol, the technique is potentially useful to monitor patient mechanics during invasive and noninvasive ventilation. FOT allows the assessment of the respiratory system linearity by measuring resistance and reactance at different lung volumes or end-expiratory pressures. Moreover, FOT allows the physician to track the changes in patient mechanics along the ventilation cycle. Applying FOT at different frequencies may allow the physician to interpret patient mechanics in terms of models with pathophysiological interest. The current methodological and technical experience make possible the implementation of portable and compact computerised FOT systems specifically addressed to its application in the mechanical ventilation setting.

Endobronchial valves in severe emphysematous patients: CT evaluation of lung fissures completeness, treatment radiological response and quantitative emphysema analysis

OBJECTIVE: To evaluate lung fissures completeness, post-treatment radiological response and quantitative CT analysis (QCTA) in a population of severe emphysematous patients submitted to endobronchial valves (EBV) implantation. MATERIALS AND METHODS: Multi-detectors CT exams of 29 patients were studied, using thin-section low dose protocol without contrast. Two radiologists retrospectively reviewed all images in consensus; fissures completeness was estimated in 5% increments and post-EBV radiological response (target lobe atelectasis/volume loss) was evaluated. QCTA was performed in pre and post-treatment scans using a fully automated software. RESULTS: CT response was present in 16/29 patients. In the negative CT response group, all 13 patients presented incomplete fissures, and mean oblique fissures completeness was 72.8%, against 88.3% in the other group. QCTA most significant results showed a reduced post-treatment total lung volume (LV) (mean 542 ml), reduced EBV-submitted LV (700 ml) and reduced emphysema volume (331.4 ml) in the positive response group, which also showed improved functional tests. CONCLUSION: EBV benefit is most likely in patients who have complete interlobar fissures and develop lobar atelectasis. In patients with no radiological response we observed a higher prevalence of incomplete fissures and a greater degree of incompleteness. The fully automated QCTA detected the post-treatment alterations, especially in the treated lung analysis.

Reference values for lung function tests: I. Static volumes

Static lung volume (LV) measurements have a number of clinical and research applications; however, no previous studies have provided reference values for such tests using a healthy sample of the adult Brazilian population. With this as our main purpose, we prospectively evaluated 100 non-smoking subjects (50 males and 50 females), 20 to 80 years old, randomly selected from more than 8,000 individuals. Gender-specific linear prediction equations were developed by multiple regression analysis with total lung capacity (TLC), functional residual capacity (FRC), residual volume (RV), RV/TLC ratio and inspiratory capacity (IC) as dependent variables, and with age, height, weight, lean body mass and indexes of physical fitness as independent ones. Simpler demographic and anthropometric variables were as useful as more complex measurements in predicting LV values, independent of gender and age (R2 values ranging from 0.49 to 0.78, P<0.001). Interestingly, prediction equations from North American and European studies overestimated the LV at low volumes and underestimated them at high volumes (P<0.05). Our results, therefore, provide a more appropriate frame of reference to evaluate the normalcy of static lung volume values in Brazilian males and females aged 20 to 80 years.

VEGF receptor expression decreases during lung development in congenital diaphragmatic hernia induced by nitrofen

Changes in vascular endothelial growth factor (VEGF) in pulmonary vessels have been described in congenital diaphragmatic hernia (CDH) and may contribute to the development of pulmonary hypoplasia and hypertension; however, how the expression of VEGF receptors changes during fetal lung development in CDH is not understood. The aim of this study was to compare morphological evolution with expression of VEGF receptors, VEGFR1 (Flt-1) and VEGFR2 (Flk-1), in pseudoglandular, canalicular, and saccular stages of lung development in normal rat fetuses and in fetuses with CDH. Pregnant rats were divided into four groups (n=20 fetuses each) of four different gestational days (GD) 18.5, 19.5, 20.5, 21.5: external control (EC), exposed to olive oil (OO), exposed to 100 mg nitrofen, by gavage, without CDH (N-), and exposed to nitrofen with CDH (CDH) on GD 9.5 (term=22 days). The morphological variables studied were: body weight (BW), total lung weight (TLW), left lung weight, TLW/BW ratio, total lung volume, and left lung volume. The histometric variables studied were: left lung parenchymal area density and left lung parenchymal volume. VEGFR1 and VEGFR2 expression were determined by Western blotting. The data were analyzed using analysis of variance with the Tukey-Kramer post hoc test. CDH frequency was 37% (80/216). All the morphological and histometric variables were reduced in the N- and CDH groups compared with the controls, and reductions were more pronounced in the CDH group (P<0.05) and more evident on GD 20.5 and GD 21.5. Similar results were observed for VEGFR1 and VEGFR2 expression. We conclude that N- and CDH fetuses showed primary pulmonary hypoplasia, with a decrease in VEGFR1 and VEGFR2 expression.

Correlations between forced oscillation technique parameters and pulmonary densitovolumetry values in patients with acromegaly

The aims of this study were to evaluate the forced oscillation technique (FOT) and pulmonary densitovolumetry in acromegalic patients and to examine the correlations between these findings. In this cross-sectional study, 29 non-smoking acromegalic patients and 17 paired controls were subjected to the FOT and quantification of lung volume using multidetector computed tomography (Q-MDCT). Compared with the controls, the acromegalic patients had a higher value for resonance frequency [15.3 (10.9-19.7) vs 11.4 (9.05-17.6) Hz, P=0.023] and a lower value for mean reactance [0.32 (0.21-0.64) vs 0.49 (0.34-0.96) cm H2O/L/s2, P=0.005]. In inspiratory Q-MDCT, the acromegalic patients had higher percentages of total lung volume (TLV) for nonaerated and poorly aerated areas [0.42% (0.30-0.51%) vs 0.25% (0.20-0.32%), P=0.039 and 3.25% (2.48-3.46%) vs 1.70% (1.45-2.15%), P=0.001, respectively]. Furthermore, the acromegalic patients had higher values for total lung mass in both inspiratory and expiratory Q-MDCT [821 (635-923) vs 696 (599-769) g, P=0.021 and 844 (650-945) vs 637 (536-736) g, P=0.009, respectively]. In inspiratory Q-MDCT, TLV showed significant correlations with all FOT parameters. The TLV of hyperaerated areas showed significant correlations with intercept resistance (rs=−0.602, P<0.001) and mean resistance (rs=−0.580, P<0.001). These data showed that acromegalic patients have increased amounts of lung tissue as well as nonaerated and poorly aerated areas. Functionally, there was a loss of homogeneity of the respiratory system. Moreover, there were correlations between the structural and functional findings of the respiratory system, consistent with the pathophysiology of the disease.