Ioanna Mitrouska

Surgery and the respiratory muscles

Respiratory muscles are the only skeletal muscles vital to life. Surgical procedures can affect the respiratory muscles by a number of pathophysiological mechanisms including thoracoabdominal mechanics, reflexes, neuromechanical coupling, and loss of muscular integrity. Impairment of respiratory muscle function after surgery may lead to postoperative complications such as hypoventilation, hypoxia, atelectasis, and infections, some of which may be life threatening. In this paper we review surgery that impairs the function of the respiratory muscles—namely cardiac, thoracic, and upper abdominal surgery. Therapeutic interventions or protective measures for respiratory muscles during or after each type of surgery are also briefly addressed. Lung transplantation and lung volume reduction surgery are discussed, since both have been shown to improve the function of respiratory muscles, and possible pathophysiological mechanisms are reviewed. The preoperative assessment of respiratory muscle function is also considered. Furthermore, when postoperative pulmonary complications occur it is worth considering whether the cause could be dysfunction of the respiratory muscles and thus a proper assessment of their function is needed. The most important function of the respiratory muscles is breathing since they are the motor arm of the respiratory system. Breathing, a lifelong task, is borne mainly by the inspiratory muscles, especially the diaphragm. The other inspiratory muscles contribute little to quiet breathing but are recruited when higher levels of ventilation are required, such as in exercise and obstructive or restrictive lung disease. The expiratory muscles are not usually used during breathing except at high levels of ventilatory effort. A second function of the respiratory muscles is to perform explosive manoeuvres such as coughing and vomiting. The respiratory muscles also have a role as stabilisers of the thorax and abdomen since they take part in the formation of the thoracic and abdominal walls. Respiratory muscle function depends on the function of the respiratory centres, …

Decreased sputum mature dendritic cells in healthy smokers and patients with chronic obstructive pulmonary disease.

Background: Asthmatics who smoke have decreased pulmonary mature dendritic cells (DCs). Chronic obstructive pulmonary disease (COPD) patients have an increased amount of pulmonary immature DCs. We hypothesized that healthy smokers and patients with COPD have decreased pulmonary mature DCs. Methods: We identified sputum DCs expressing the maturation markers CD83 and DC-lysosome associated membrane protein (DC-LAMP) and DC subpopulations (i.e. myeloid and plasmacytoid DCs) by flow cytometry in healthy smokers before they entered a smoking cessation trial (n = 30), in the same smokers after 6 months of smoking cessation (n = 11) and in COPD patients (n = 28, 14 current and 14 ex-smokers). 12 healthy never-smokers served as controls. DC numbers were expressed as percentage of total sputum CD45+ leukocytes. Results: CD83+ and DC-LAMP+ mature DCs were decreased in healthy smokers before they ceased smoking compared to after (p = 0.003 and p = 0.049, respectively) and in smokers before smoking cessation compared to never-smokers (p = 0.027 and p = 0.028, respectively). COPD patients, both current and ex-smokers, showed decreased CD83+ mature DCs compared to never-smokers and smokers after cessation (p = 0.042 and p = 0.004, respectively). Conclusions: Cigarette smoking and COPD per se are associated with a decrease in pulmonary mature DCs. We speculate that this reduction is involved in the immunopathogenesis of smoking-related respiratory disorders, such as COPD.

Peripheral Arterial Embolism Due to a Left Ventricular Diverticulum in a Young Adult

A 32-year-old man was admitted to the emergency department of our hospital after experiencing a peripheral arterial embolism. Investigation of the possible embolic sources in an otherwise asymptomatic patient revealed the existence of a left ventricular diverticulum. The left ventricular diverticulum is a rare congenital anomaly, either isolated or as a part of a syndrome including other congenital malformations. The treatment of choice, especially in symptomatic patients, is surgical resection, while in asymptomatic patients anticoagulation therapy is indicated.

Sputum and nasal lavage lung-specific biomarkers before and after smoking cessation

BackgroundLittle is known about the effect of smoking cessation on airway inflammation. Secretory Leukocyte Protease Inhibitor (SLPI), Clara Cell protein 16 (CC16), elafin and human defensin beta-2 (HBD-2) protect human airways against inflammation and oxidative stress. In this longitudinal study we aimed to investigate changes in sputum and nasal lavage SLPI, CC16, elafin and HBD-2 levels in healthy smokers after 6 and 12 months of smoking cessation.MethodsInduced sputum and nasal lavage was obtained from healthy current smokers (n = 76) before smoking cessation, after 6 months of smoking cessation (n = 29), after 1 year of smoking cessation (n = 22) and from 10 healthy never smokers. SLPI, CC16, elafin and HBD-2 levels were measured in sputum and nasal lavage supernatants by commercially available ELISA kits.ResultsSputum SLPI and CC-16 levels were increased in healthy smokers before smoking cessation versus never-smokers (p = 0.005 and p = 0.08 respectively). SLPI and CC16 levels did not differ before and 6 months after smoking cessation (p = 0.118 and p = 0.543 respectively), neither before and 1 year after smoking cessation (p = 0.363 and p = 0.470 respectively). Nasal lavage SLPI was decreased 12 months after smoking cessation (p = 0.033). Nasal lavage elafin levels were increased in healthy smokers before smoking cessation versus never-smokers (p = 0.007), but there were no changes 6 months and 1 year after smoking cessation.ConclusionsOnly nasal lavage SLPI decrease after 1 year after smoking cessation. We may speculate that there is an ongoing inflammatory process stimulating the production of counter-regulating proteins in the airways of healthy ex-smokers.

Effect of digoxin on global respiratory muscle strength after cholecystectomy: a double blind study

BACKGROUND Upper abdominal surgery has been shown to impair the function of the respiratory muscles. In addition, controversial results have been reported concerning the effect of digoxin on the diaphragm. The aim of this study was to investigate further the mechanism(s) of respiratory muscle dysfunction after cholecystectomy and the effect of digoxin on the impaired respiratory muscle function. METHODS Twenty three patients (four men) were studied before and 48 hours after surgery. Eleven received digoxin and 12 placebo. Respiratory muscle strength was assessed 48 hours after surgery by measuring mouth pressure during maximum static inspiratory (Pimax) and expiratory (Pemax) efforts before and after 90 minutes of intravenous administration of 0.25 mg digoxin in a double blind, placebo controlled fashion. In addition, spirometric and pain measurements were performed. RESULTS Postoperatively (+48 h) Pimax and Pemax decreased significantly (p<0.01) from their preoperative values in both groups by a similar degree. After administration of digoxin or placebo only the digoxin group showed a significant increase in both Pimax (p<0.02) and Pemax (p<0.05) with a mean increase of 15% for Pimax and 12.3% for Pemax. The mean difference in PImax (ΔPimax) and Pemax (ΔPemax) between the digoxin and placebo groups was 1.01 (95% CI 0.28 to 2.2) and 1.05 (95% CI 0.04 to 2.4), respectively. Estimates of postoperative pain did not differ between the two groups. Spirometric indices showed a similar restrictive defect postoperatively in both groups but did not change after digoxin or placebo. CONCLUSION Digoxin improves the impaired global strength of the inspiratory and expiratory muscles after cholecystectomy and this may be clinically relevant. Muscle contractility could play a part in this impairment.

Maintained smoking cessation for 6 months equilibrates the percentage of sputum CD8+ lymphocyte cells with that of nonsmokers.

Little is known about the longitudinal effects of smoking cessation on sputum inflammatory cells. We aimed to investigate the changes in sputum inflammatory cells and T-lymphocyte subpopulations after 6 and 12 months smoking cessation. Induced sputum was obtained from 68 healthy smokers before and after 6 months (n = 21) and 1 year (n = 14) smoking cessation and from ten healthy never-smokers. Inflammatory cells were identified by morphology and T-lymphocyte subpopulations by flow cytometry. Sputum macrophages were decreased after 12 months of smoking cessation in comparison to baseline, while neutrophils increased. Moreover, CD8+ T-cells were decreased in smokers before smoking cessation compared to never-smokers and increased in smokers after 6 months of smoking cessation in comparison to baseline; result that was maintained after 1 year of smoking cessation. These novel findings indicate that smoking cessation can equilibrate certain inflammatory cells of smokers with those of nonsmokers, within 6 months of smoking cessation.

Vascular-Specific Growth Factor mRNA Levels in the Human Diaphragm

Backround: Angiogenesis is an adaptation mechanism of skeletal muscles to increased load. Animal data have shown increased vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF) and transforming growth factor-β1 (TGF-β1) mRNA levels in the diaphragm as a result of increased minute ventilation, but there are no data concerning the human diaphragm. Objectives: The purpose of this study was to investigate the VEGF, bFGF, TGF-β1 mRNA levels in the human diaphragm of normal subjects and patients with altered respiratory mechanics. Methods: We studied 9 patients with chronic obstructive pulmonary disease (COPD), 4 obese patients and 12 controls. We performed multiplex semiquantitative reverse transcription polymerase chain reaction to determine the VEGF, bFGF and TGF-β1 mRNA levels in specimens taken from their diaphragm. Results: VEGF mRNA levels were 18% higher in COPD patients compared with controls (p = 0.04), while for the obese patients, these levels were not statistically significantly different. bFGF and TGF-β1 mRNA levels in COPD patients or obese individuals compared with controls did not differ significantly either. Conclusions: The results of our study showed that TGF-β1, VEGF and bFGF mRNA was detected in the human diaphragm. The VEGF levels were higher in COPD patients than in normal subjects. This upregulation of VEGF may suggest an enhancement of angiogenesis in the diaphragm in COPD patients.

Effect of voluntary respiratory efforts on breath-holding time

INTRODUCTION Near the end of a maximal voluntary breath-hold, re-inhalation of the expired gas allows an additional period of breath-holding, indicating that the breaking point does not depend solely on chemical drive. We hypothesized that afferents from respiratory muscle and/or chest wall are significant in breath-holding. METHODS Nineteen normal adults breathed room air through a mouthpiece connected to a pneumotachograph and were instructed to breath-hold with and without voluntary regular respiratory efforts against an occluded airway. RESULTS Fifty one trials with and 53 without respiratory efforts were analyzed. The mean number of efforts per minute was 19+/-2.3 and the mean lowest airway pressure (P(aw)) -16.6+/-5.4 cmH(2)O. Breath-holding time (BHT) did not differ without (33.0+/-18.2 s) and with (29.3+/-12.3 s) efforts. In five patients arterial blood gasses were measured before and at the end of breath-holding and they did not differ between trials without and with efforts, indicating similar chemical drive. Our results suggest that afferents from respiratory muscle and/or chest wall are not the major determinants of BHT.

Evaluation of acid-base status in patients admitted to ED—physicochemical vs traditional approaches

BACKGROUND The aim of this study is to evaluate the value of physicochemical, base excess (BE), and plasma bicarbonate concentration ([HCO3(-)]) approaches on the assessment of acid-base status in patients presented to the emergency department (ED). METHODS Upon presentation at ED, patients whose arterial blood was deemed in need of analysis were studied. Arterial blood gases, serum electrolytes, and proteins were measured and used to derive [HCO3(-)], BE, anion gap (AG), AG adjusted for albumin (AGadj), strong ion difference, strong ion gap (SIG) and SIG corrected for water excess/deficit (SIGcor). In each patient the acid-base status was evaluated using the BE, [HCO3(-)], and physicochemical approaches. RESULTS A total of 365 patients were studied. Compared with BE (n = 202) and [HCO3(-)] (n = 151), physicochemical approach (n = 279) identified significantly more patients with metabolic acid-base disturbances (P < .0001). Significantly fewer patients with unmeasured anions acidosis were identified with AGadj than with SIGcor (164 vs 230; P < .0001). On the basis of BE, 75 patients had normal acid-base balance, and 65 (87%) of them exhibited at least 1 hidden acid-base disturbance, identified by the physicochemical approach. The corresponding values with [HCO3(-)] approach were 108 and 95 (88%) patients. When patients with high AGadj were excluded, 44 patients with BE and 67 with [HCO3(-)] approach had normal acid-base status, and most of them exhibited at least 1 acid-base disturbance with the physicochemical approach, whereas 12 and 21 patients, respectively, had high SIGcor. CONCLUSION Compared with the BE and [HCO3(-)] methods, the physicochemical approach has a better diagnostic accuracy to identify metabolic acid-base disturbances.

Is a miliary chest pattern always indicative of tuberculosis or malignancy

Case Report A 36-year-old Caucasian woman presented with a 10-month history of increased dyspnea on exertion that pro-gressed to marked shortness of breath at rest a few days prior to hospital admission. Her past medical history in-cluded a hysterectomy 24 months previously, secondary to the enucleation of a leiomyoma, which was compli-cated by uncontrolled bleeding. Physical examination was remarkable for labored respirations with a rate of 28 breaths/min and inspiratory crackles at both lungs. PaO