Mehrdad Behnia

Impact of COPD on pulmonary complications and on long-term survival of patients undergoing surgery for NSCLC.

PURPOSE The purpose of our study was to determine the incidence of various types of postoperative pulmonary complications and to evaluate the impact of chronic obstructive pulmonary disease (COPD) on the long-term survival of patients with non-small cell lung cancer (NSCLC) undergoing pulmonary resection. METHODS We performed a retrospective chart review of 244 patients who had undergone lung resection for NSCLC at Indiana University. COPD, defined as predicted forced expiratory volume in 1 s (FEV1)< or =70% and FEV1/FVC< or =70%, was determined based on preoperative pulmonary function testing in 78 of 244 patients (COPD group). The remaining 166 patients were classified as non-COPD. The incidence of postoperative complications, which included air leak of > or=10 days, atelectasis, pneumothorax, pneumonia, bronchopleural fistula, empyema, acute respiratory distress syndrome, mechanical ventilation of > or =7 days, and outpatient oxygen supplementation were compared between the two groups. Long-term survival and mortality due to respiratory failure were analyzed between the two groups using the Kaplan-Meier method and log rank test. RESULTS All of the above-stated postoperative pulmonary complications occurred more frequently in the COPD than in the non-COPD patients (all P<0.01). The overall 5-year survival rate was 36.2% in the COPD and 41.2% in the non-COPD patients (P=0.1023). Five-year cancer related survival was 43.2% in the COPD and 47.7% in the non-COPD patients (P=0.357). There was no significant difference in survival among patients with different stages of lung cancer. However, the intercurrent survival, which is associated with non-cancer related death, was 60.1% in patients with COPD and 86.2% in patients without COPD at 5 years (P<0.0001). The major cause of non-cancer related death in the COPD group was respiratory failure (P=0.0008). CONCLUSION The presence of COPD is an acceptable predictor of postoperative pulmonary complications in patients with NSCLC. COPD is also a significant risk factor for development of respiratory-related complications, which may explain the poor long-term survival in these patients.

Adjuvant bleomycin, etoposide and cisplatin in pathological stage II non-seminomatous testicular cancer. the Indiana University experience.

Two cycles of bleomycin, etoposide, and cisplatin (BEP) were evaluated as adjuvant chemotherapy for patients with pathological stage II non-seminomatous germ cell tumours. Between 1985 and 1995, 86 patients with pathological stage II non-seminomatous testicular cancer were treated with two cycles of BEP. At retroperitoneal lymph node dissection (RPLND) 49 patients (57%) had pathological stage II(A) (microscopic nodal metastases) and 37 (43%) had stage II(B) (gross nodal metastases). After RPLND, the patients received bleomycin, 30 units weekly for 8 weeks, etoposide (100 mg/m(2)) and cisplatin (20 mg/m(2)) each for 5 days every 28 days for two cycles as adjuvant chemotherapy. 4 patients were lost to follow-up. 10 patients (12%) developed granulocytopenic fever during their chemotherapy. Of the 82 evaluable patients all remained with no evidence of disease except for a single patient with a cervical nodal relapse of teratoma. This was resected and he remains disease free. Median follow-up has been 85 months (range: 42-173 months). In patients with fully resected stage II non-seminomatous germ cell tumour, two cycles of BEP were almost universally effective in preventing relapse.

Nosocomial and ventilator-associated pneumonia in a community hospital intensive care unit: a retrospective review and analysis

BackgroundNosocomial and ventilator-associated pneumonia (VAP) are causes of significant morbidity and mortality in hospitalized patients. We analyzed a) the incidence and the outcome of pneumonias caused by different pathogens in the intensive care unit (ICU) of a medium-sized twenty-four bed community hospital and b) the incidence of complications of such pneumonias requiring surgical intervention such as thoracotomy and decortication.ResultsWe retrospectively reviewed the charts of patients diagnosed with nosocomial and ventilator-associated pneumonia in our ICU. Their bronchoalveolar lavage (BAL) and sputum cultures, antibiograms, and other clinical characteristics, including complications and need for tracheostomy, thoracotomy and decortication were studied. In a span of one year (2011–12), 43 patients were diagnosed with nosocomial pneumonia in our ICU. The median simplified acute physiology score (SAPS II) was 39. One or more gram negative organisms as the causative agents were present in 85% of microbiologic samples. The three most prevalent gram negatives were Stenotrophomonas maltophilia (34%), Pseudomonas aeurginosa (40%), and Acinetobacter baumannii (32%). Twenty eight percent of bronchoalveolar samples contained Staphylococcus aureus. Eight three percent of patients required mechanical ventilation postoperatively and 37% underwent tracheostony. Thirty five percent underwent thoracotomy and decortication because of further complications such as empyema and non-resolving parapneumonic effusions. A. baumannii, Klebsiella pneumonia extended spectrum beta lactam (ESBL) and P. aeurginosa had the highest prevalence of multi drug resistance (MDR). Fifteen patients required surgical intervention. Mortality from pneumonia was 37% and from surgery was 2%.ConclusionNosocomial pneumonias, in particular the ones that were caused by gram negative drug resistant organisms and their ensuing complications which required thoracotomy and decortication, were the cause of significant morbidity in our intensive care unit. Preventative and more intensive and novel infection control interventions in reducing the incidence of nosocomial pneumonias are strongly emphasized.

Management of myxedematous respiratory failure: review of ventilation and weaning principles.

Respiratory failure in myxedema is a complex medical emergency and may require prolonged ventilatory assistance. Appropriate management of this medical problem requires an understanding of its effects on the central nervous system and peripheral neuromusculoskeletal system. Weaning of these patients can be very protracted and requires a diligent multidisciplinary approach. Because of its infrequency, ventilatory management of severe hypothyroidism has not been studied in a controlled fashion. The first part of this review discusses the mechanisms of respiratory failure in myxedema. The second part explores strategies in mechanical ventilation and weaning of myxedematous patients.

Persistent Cough: Causes and Cures

Refractory cough in a patient with a normal chest X-ray usually falls into one of five categories: drug-induced (especially by ACE inhibitors), secondary to postnasal discharge, gastroesophageal reflux, or hyperactive airway disease, and idiopathic but responsive to nebulized lidocaine. The history may point to the most likely cause, and empiric therapy may confirm the diagnosis.

Alveolar-Capillary reserve during exercise in patients with chronic obstructive pulmonary disease

Background Factors limiting exercise in patients with COPD are complex. With evidence for accelerated pulmonary vascular aging, destruction of alveolar–capillary bed, and hypoxic pulmonary vasoconstriction, the ability to functionally expand surface area during exercise may become a primary limitation. Purpose To quantify measures of alveolar–capillary recruitment during exercise and the relationship to exercise capacity in a cohort of COPD patients. Methods Thirty-two subjects gave consent (53% male, with mean ± standard deviation age 66±9 years, smoking 35±29 pack-years, and Global Initiative for Chronic Obstructive Lung Disease (GOLD) classification of 0–4: 2.3±0.8), filled out the St George’s Respiratory Questionnaire (SGRQ) to measure quality of life, had a complete blood count drawn, and underwent spirometry. The intrabreath (IB) technique for lung diffusing capacity for carbon monoxide (IBDLCO) and pulmonary blood flow (IBQc, at rest) was also performed. Subsequently, they completed a cycle ergometry test to exhaustion with measures of oxygen saturation and expired gases. Results Baseline average measures were 44±21 for SGRQ score and 58±11 for FEV1/FVC. Peak oxygen consumption (VO2) was 11.4±3.1 mL/kg/min (49% predicted). The mean resting IBDLCO was 9.7±5.4 mL/min/mmHg and IBQc was 4.7±0.9 L/min. At the first workload, heart rate (HR) increased to 92±11 bpm, VO2 was 8.3±1.4 mL/kg/min, and IBDLCO and IBQc increased by 46% and 43%, respectively, compared to resting values (p,0.01). The IBDLCO/Qc ratio averaged 2.0±1.1 at rest and remained constant during exercise with marked variation across subjects (range: 0.8–4.8). Ventilatory efficiency plateaued at 37±5 during exercise, partial pressure of mix expired CO2/partial pressure of end tidal CO2 ratio ranged from 0.63 to 0.67, while a noninvasive index of pulmonary capacitance, O2 pulse × PetCO2 (GxCap) rose to 138%. The exercise IBDLCO/Qc ratio was related to O2 pulse (VO2/HR, r=0.58, p<0.01), and subjects with the highest exercise IBDLCO/Qc ratio or the greatest rise from rest had the highest peak VO2 values (r=0.65 and 0.51, respectively, p<0.05). Of the noninvasive gas exchange measures of pulmonary vascular function, GxCap was most closely associated with DLCO, DLCO/Qc, and VO2 peak. Conclusion COPD patients who can expand gas exchange surface area as assessed with DLCO during exercise relative to pulmonary blood flow have a more preserved exercise capacity.

Correlation of Stroke Volume Measurement between Sonosite Portable Echocardiogram and Edwards Flotrac Sensor-Vigileo Monitor in an Intensive Care Unit

Purpose Stroke volume (SV) is a parameter that is being recognized as an endpoint in fluid resuscitation algorithms. Its role is now being realized as an important variable in hemodynamic assessment in various clinical scenarios such as septic and cardiogenic shocks. Direct measurement of stroke volume (SV) and its novel corollary, stroke volume variation (SVV) derived by proprietary software, are preferred over mean cardiac output (CO) measurements because they render a more accurate reflection of hemodynamic status independent of heart rate. Flotrac-Vigileo monitor (FTV) (Edwards Lifesciences, Irvine, CA, USA) is a system that uses a complex algorithm analyzing arterial waveform to calculate SV, SVV, and CO. We assessed the feasibility of obtaining SV measurements with a portable echocardiogram and validated its accuracy with the FTV system in mechanically ventilated patients in our intensive care unit (ICU). Furthermore, we emphasized the importance of hemodynamic measurements and familiarity with critical care echocardiography for the intensivists. Methods Ten patients who were on mechanical ventilation were studied. A femoral arterial line was connected to the FTV system monitoring SV and CO. A portable echocardiogram (M-Turbo; Sonosite, Bothell, WA) was used to measure SV. CO was calculated by multiplying SV by heart rate. No patient had arrhythmia. We used biplane Simpsons method of discs to calculate SV in which subtraction of end-systolic volume from end-diastolic volume yields the SV Results The comparison of simultaneous SV and CO measurements by echocardiography with FTV showed a strong correlation between the 2. (For SV, y = 0.9545x + 3.3, R2 = 0.98 and for CO, y = 0.9104x + 7.7074, R2 = 0.97). Conclusions In our small cohort, the SV and CO measured by a portable echocardiogram (Sonosite M-Turbo) appears to be closely correlated with their respective values measured by FTV. Portable echocardiography is a reliable noninvasive tool for the hemodynamic assessment of the critically ill. Its results need further validation with gold standard measures in a larger cohort of patients. However, our results suggest portable echocardiography could be an attractive tool in assessment of different hemodynamic scenarios in the critically ill.

A new approach to blood flow simulation in vascular networks.

A proper analysis of blood flow is contingent upon accurate modelling of the branching pattern and vascular geometry of the network of interest. It is challenging to reconstruct the entire vascular network of any organ experimentally, in particular the pulmonary vasculature, because of its very high number of vessels, complexity of the branching pattern and poor accessibility in vivo. The objective of our research is to develop an innovative approach for the reconstruction of the full pulmonary vascular tree from available morphometric data. Our method consists of the use of morphometric data on those parts of the pulmonary vascular tree that are too small to reconstruct by medical imaging methods. This method is a three-step technique that reconstructs the entire pulmonary arterial tree down to the capillary bed. Vessels greater than 2 mm are reconstructed from direct volume and surface analysis using contrast-enhanced computed tomography. Vessels smaller than 2 mm are reconstructed from available morphometric and distensibility data and rearranged by applying Murrays laws. Implementation of morphometric data to reconstruct the branching pattern and applying Murrays laws to every vessel bifurcation simultaneously leads to an accurate vascular tree reconstruction. The reconstruction algorithm generates full arterial tree topography down to the first capillary bifurcation. Geometry of each order of the vascular tree is generated separately to minimize the construction and simulation time. The node-to-node connectivity along with the diameter and length of every vessel segment is established and order numbers, according to the diameter-defined Strahler system, are assigned. In conclusion, the present model provides a morphological foundation for future analysis of blood flow in the pulmonary circulation

The Effect of Aging on Relationships between Lean Body Mass and VO2max in Rowers.

Aging is associated with a fall in maximal aerobic capacity as well as with a decline in lean body mass. The purpose of the study was to investigate the influence of aging on the relationship between aerobic capacity and lean body mass in subjects that chronically train both their upper and lower bodies. Eleven older rowers (58±5 yrs) and 11 younger rowers (27±4 yrs) participated in the study. Prior to the VO2max testing, subjects underwent a dual energy X-ray absorptiometry scan to estimate total lean body mass. Subsequently, VO2max was quantified during a maximal exercise test on a rowing ergometer as well as a semi-recumbent cycle ergometer. The test protocol included a pre-exercise stage followed by incremental exercise until VO2max was reached. The order of exercise modes was randomized and there was a wash-out period between the two tests. Oxygen uptake was obtained via a breath-by-breath metabolic cart (Vmax™ Encore, San Diego, CA). Rowing VO2max was higher than cycling VO2max in both groups (p<0.05). Older subjects had less of an increase in VO2max from cycling to rowing (p<0.05). There was a significant relationship between muscle mass and VO2max for both groups (p<0.05). After correcting for muscle mass, the difference in cycling VO2max between groups disappeared (p>0.05), however, older subjects still demonstrated a lower rowing VO2max relative to younger subjects (p<0.05). Muscle mass is associated with the VO2max obtained, however, it appears that VO2max in older subjects may be less influenced by muscle mass than in younger subjects.

Numerical simulation of flow, heat and moisture transfer in heat and moisture exchanger (HME) devices

Heat and Moisture Exchanger (HME) is a simple solution to the problems of warming and humidification of inspired gases during ventilator treatment. The device acts as an “artificial” nose or passive humidifier, added to the breathing circuit to retain and exchange heat and moisture between inspiration and expiration. The HME traps expiratory heat and moisture from patient’s exhaled breath in a porous medium and returns a portion of them through the subsequent inspiratory cycle. The aim of our paper is to develop a computational fluid dynamics (CFD) model of an HME device commonly used in anaesthesia and intensive care. The CFD results allow a better understanding of flow behaviour leading to the design of more efficient devices. The CFD model solves the gas flow, heat and mass transfer equations in a DAR Hygrobac S (Mallinckrodt DAR, Mirandola, Italy). The temperature, absolute humidity and pressure fields are obtained during expiratory phase to evaluate heat and moisture conserving efficiencies and air flow resistance. The effect of flow rate as one of the major parameters in ventilator setting on temperature, humidity and pressure drop is determined. Inside the HME device, areas of recirculation are observed. As the flow rate increases the output temperature and absolute humidity go up causing a reduction in heat and moisture conserving capacities. Comparison of the CFD results with previously obtained experimental data shows a satisfactory agreement.