Naoki Hayama

High-flow nasal cannula oxygen therapy for acute exacerbation of interstitial pneumonia: A case series

We report 3 cases (all men, age: 69-81 years) of acute exacerbation of interstitial pneumonia (AEIP) that were successfully treated with a high-flow nasal cannula (HFNC), which delivers heated, humidified gas at a fraction of inspired oxygen (FIO2) up to 1.0 (100%). Oxygenation was insufficient under non-rebreathing face masks; however, the introduction of HFNC with an FIO2 of 0.7-1.0 (flow rate: 40 L/min) improved oxygenation and was well-tolerated until the partial pressure of oxygen in blood/FIO2 ratio increased (between 21 and 26 days). Thus, HFNC might be an effective and well-tolerated therapeutic addition to the management of AEIP.

Role of cholinergic neural transmission on airway resistance in the dog

The unique contractile profiles of bronchial smooth muscle (Kondo et al., 1995) and its neural control were investigated by comparing responses of the bronchus and trachea to acute hypercapnia, stimulation of vagus efferent fibers before and after intravenous atropine, and intravenous acetylcholine in decerebrated and paralyzed dogs. During acute hypercapnia, airway resistance represented by peak airway pressure (Pedley et al., 1970) significantly increased as well as tracheal tension (Ttr). During electric stimulation of the vagal efferent fibers, Ttr increased and was sustained throughout the simulation period while the peak airway pressure was not maintained at the peak level. The peak Ttr and the airway resistance (Raw) calculated from ventilatory flow and airway pressure increased with increases in intensity of electric stimulation. Ttr reached its maximal level at an intensity 16 times of the threshold (T), while Raw became maximal at 4T. Although both the Ttr-stimulus intensity and Raw-intensity curves were shifted to the right by administration of intravenous atropine, the Raw curve shifted more to the right than the Ttr curve with the same dose of atropine. When muscular muscarinic receptors were directly stimulated by intravenous acetylcholine, Ttr once increased and then decreased promptly while peak airway pressure remained at a high level for a few minutes. These findings suggested that the bronchus is more sensitive to vagal efferent stimulation and susceptible to competitive antagonist of actylcholine than the trachea. In conclusion, the contractile profiles of the fifth-order bronchus we have reported (Kondo et al., 1995) were reflected in airway resistance, and the neuromuscular junction may be the site of adaptation of bronchoconstrictor response to motor nerve adaptation.

A Case of Pulmonary Varix Associated with Superior Pulmonary Vein Occlusion

A pulmonary varix is a localized dilatation of a pulmonary vein, which is usually asymptomatic presented as a mass on a chest roentgenogram, and diagnosed with pulmonary angiography. We encountered a case of 55 year-old man, in whom incidentally identified was a dilated blood vessel that passed through the minor fissure and returned to the inferior pulmonary vein, which we diagnosed as pulmonary varix. This vascular anomaly was accompanied by the occluded superior pulmonary vein, highly suggestive of the developmental mechanism of this disease.

Clinical contributions of exhaled volatile organic compounds in the diagnosis of lung cancer

Background Exhaled volatile organic compounds (VOC) are being considered as biomarkers for various lungs diseases, including cancer. However, the accurate measurement of extremely low concentrations of VOC in expired air is technically challenging. We evaluated the clinical contribution of exhaled VOC measured with a new, double cold-trap method in the diagnosis of lung cancer. Methods Breath samples were collected from 116 patients with histologically confirmed lung cancer and 37 healthy volunteers (controls) after inspiration of purified air, synthesized through a cold-trap system. The exhaled VOC, trapped in the same system, were heat extracted. We analyzed 14 VOC with gas chromatography. Results The concentrations of exhaled cyclohexane and xylene were significantly higher in patients with lung cancer than in controls (p = 0.002 and 0.0001, respectively), increased significantly with the progression of the clinical stage of cancer (both p < 0.001), and decreased significantly after successful treatment of 6 patients with small cell lung cancer (p = 0.06 and 0.03, respectively). Conclusion Measurements of exhaled VOCs by a double cold-trap method may help diagnose lung cancer and monitor its progression and regression.

Endobronchial Hamartoma as a Cause of Pneumonia

Patient: Male, 66 Final Diagnosis: Endobronchial hamartoma Symptoms: Fever Medication: — Clinical Procedure: Flexible bronchoscopy • surgical resection Specialty: Pulmonology Objective: Unusual clinical course Background: Post-obstructive pneumonia occurs in the presence of airway obstruction, usually caused by lung cancer. However, there are cases of bronchial obstruction due to benign origin such as foreign bodies and benign endobronchial tumors, which are often misdiagnosed. Case Report: A 66-year-old man was referred to our hospital due to high fever with abnormal shadow in the right lung. Chest computed tomography after a course of antibiotic treatment showed an intra-bronchial tumor obstructing the right upper bronchus. Part of the tumor was removed with flexible bronchoscopy, and histopathological examination revealed cartilage tissue but not fat or other components. Lobectomy of the right upper lobe of the lung was performed to make a definite diagnosis and prevent recurrent obstructive pneumonia. The resected tumor contained mature cartilage and fat tissues, and was diagnosed as endobronchial hamartoma. Conclusions: Benign endobronchial tumors such as hamartomas should be considered in the differential diagnosis of post-obstructive pneumonia.

Lung Cancer Associated with Seronegative Myasthenia Gravis

A 64-year-old man presented with diplopia, muscle weakness, a pulmonary nodule and mediastinal widening on a chest radiograph. He was diagnosed with clinical stage IIIA (T2aN2M0) lung cancer. His neurological symptoms worsened following the initiation of thoracic radiation therapy (60 Gy) and chemotherapy. A diagnosis of myasthenia gravis (MG) was confirmed with a repetitive nerve stimulation test that showed a waning pattern, and a positive edrophonium test, although neither anti-acetylcholine receptor antibodies nor anti-muscle-specific tyrosine kinase antibodies were detected. The ptosis and limb muscle weakness improved with prednisolone and acetylcholinesterase inhibitor treatment, and a partial response of the lung cancer to chemoradiotherapy was obtained. However, the ptosis and limb muscle weakness worsened again following a recurrence of the lung cancer. The herein described case, in which lung cancer and MG occurred and recurred simultaneously, suggests that MG can develop as a paraneoplastic syndrome of lung cancer.

Effect of the respiratory-related bronchial rhythmic constriction on alveolar ventilation in the dog.

The middle-sized bronchus constricts during mid-inspiration through early-expiration. The purpose of this study was to elucidate the physiological role of this respiratory-related bronchial rhythmic constriction (RRBRC). The following parameters were measured in 12 decerebrated and paralyzed dogs: pressure from a balloon-tipped catheter in the fifth-generation bronchus (to reveal RRBRC), efferent neurogram from C(5) phrenic, and ventilatory flow and volume. We found a small but significant reduction of peak expiratory flow of mechanical ventilation during RRBRC. During bilateral vagal cold block, RRBRC was simulated by intermittent electric stimulation of vagal fibers distal to the cold block. This stimulus evoked a decrease in peak expiratory flow and in Pa(CO2) (approximately 1.5 mmHg). After vagal warming, mechanical ventilation was terminated, and blood gases were maintained normal by extracorporeal oxygenation. During each RRBRC ventilatory volume decreased by approximately 3 ml. The changes in gas volume and RRBRC disappeared after bilateral vagotomy. These findings support the concept that the physiological role of RRBRC is to facilitate alveolar gas exchange by reducing expiratory flow, anatomical dead space, or both.

Proportion and clinical characteristics of non-asthmatic non-smokers among adults with airflow obstruction

Background and objectives Chronic obstructive pulmonary disease (COPD) mainly develops after long-term exposure to cigarette or biomass fuel smoke, but also occurs in non-smokers with or without a history of asthma. We investigated the proportion and clinical characteristics of non-smokers among middle-aged to elderly subjects with airflow obstruction. Methods We retrospectively analyzed 1,892 subjects aged 40–89 years who underwent routine preoperative spirometry at a tertiary university hospital in Japan. Airflow obstruction was defined as a forced expiratory volume in 1 second (FEV1)/forced vital capacity < 0.7 or as the lower limit of the normal. Results Among 323 patients presenting with FEV1/forced vital capacity < 0.7, 43 had asthma and 280 did not. Among the non-asthmatic patients with airflow obstruction, 94 (34%) were non-smokers. A larger number of women than men with airflow obstruction had asthma (26% vs. 7.6%, p < 0.001), or were non-smokers among non-asthmatics (72% vs. 20%, p < 0.001). Non-asthmatic non-smokers, rather than non-asthmatic smokers, asthmatic non-smokers, and asthmatic smokers, exhibited better pulmonary function (median FEV1: 79% of predicted FEV1 vs. 73%, 69%, and 66%, respectively, p = 0.005) and less dyspnea on exertion (1% vs. 12%, 12%, and 28%, respectively, p = 0.001). Pulmonary emphysema on thoracic computed tomography was less common in non-smokers (p < 0.001). Using the lower limit of the normal to define airflow obstruction yielded similar results. Conclusions There are a substantial number of non-smokers with airflow obstruction compatible with COPD in Japan. In this study, airflow obstruction in non-smokers was more common in women and likelier to result in mild functional and pathological abnormalities than in smokers. Further studies are warranted to investigate the long-term prognosis and appropriate management of this population in developed countries, especially in women.

Post-bronchoscopy pneumonia in patients suffering from lung cancer: Development and validation of a risk prediction score

BACKGROUND The incidence, risk factors, and consequences of pneumonia after flexible bronchoscopy in patients with lung cancer have not been studied in detail. METHODS We retrospectively analyzed the data from 237 patients with lung cancer who underwent diagnostic bronchoscopy between April 2012 and July 2013 (derivation sample) and 241 patients diagnosed between August 2013 and July 2014 (validation sample) in a tertiary referral hospital in Japan. A score predictive of post-bronchoscopy pneumonia was developed in the derivation sample and tested in the validation sample. RESULTS Pneumonia developed after bronchoscopy in 6.3% and 4.1% of patients in the derivation and validation samples, respectively. Patients who developed post-bronchoscopy pneumonia needed to change or cancel their planned cancer therapy more frequently than those without pneumonia (56% vs. 6%, p<0.001). Age ≥70 years, current smoking, and central location of the tumor were independent predictors of pneumonia, which we added to develop our predictive score. The incidence of pneumonia associated with scores=0, 1, and ≥2 was 0, 3.7, and 13.4% respectively in the derivation sample (p=0.003), and 0, 2.9, and 9.7% respectively in the validation sample (p=0.016). CONCLUSIONS The incidence of post-bronchoscopy pneumonia in patients with lung cancer was not rare and associated with adverse effects on the clinical course. A simple 3-point predictive score identified patients with lung cancer at high risk of post-bronchoscopy pneumonia prior to the procedure.

Contribution of brainstem hypoperfusion to the tracheal and phrenic nerve responses to high-pressure lung inflation in the dog

Lung inflation to high airway pressure is known to produce tracheal constriction following an initial dilation. This is attributed to stimulation of various pulmonary receptors. In an attempt to find cause of this response, we investigated in 20 decerebrated, tracheostomized and paralyzed dogs changes in the tracheal smooth muscle tension, arterial pressure and the phrenic nerve activity to high-pressure lung inflation. A high-pressure lung inflation evoked a contraction of tracheal smooth muscle following its short-lasting relaxation, and a persistent hypotension. After hilar denervation which eliminated all pulmonary afferents, a high-pressure lung inflation still evoked contraction of tracheal smooth muscle (an increase of 3.7 times) and augmented amplitude and frequency of phrenic bursts. Bilateral transections of sympathetic fibers to the lung, or blockade of arterial perfusion to the carotid sinus and denervation of the carotid sinus bilaterally did not alter the tracheal muscle and phrenic responses to a high-pressure lung inflation. We further found that severe hypotension alone caused similar responses of the tracheal smooth muscle contraction and augmented phrenic activity. Finally, when blood supply to the brainstem was transiently obstructed by clamping both the vertebral and internal carotid arteries bilaterally, the same responses were observed. In contrast, when blood hypoperfusion to the brainstem was prevented by means of extracorporeal circulation, a high-pressure lung inflation failed to evoke such contraction of tracheal smooth muscle and or increased phrenic activity. After transection of the vagus nerves bilaterally at the cervical level the tracheal muscle response to lung inflation was abolished but that of phrenic nerve was preserved. We concluded that the tracheal smooth muscle contraction and phrenic responses induced by high-pressure lung inflation may be in part attributed to brainstem hypoperfusion.