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Web 版［公開日：2012 年 7 月 23 日］◉ Case Report ◉Severe Obstructive Respiratory Failure Successfully Treatedwith High-Frequency Oscillatory Ventilation
Kohei OTA，Shinichiro OHSHIMO，Yoshiko KIDA，Tomoko TAMURA
Kazunobu UNE，Tadatsugu OTANI，Satoshi YAMAGA，Yasumasa IWASAKI
Nobuyuki HIROHASHI，Koichi TANIGAWA
Key words：active expiration，air-trapping，auto-PEEP，barotrauma，lung-protective ventilation

Abstract
High-frequency oscillatory ventilation（HFOV）is a lung-protective ventilatory method that prevents airway
collapse and overdistention of the lung. For severe obstructive pulmonary diseases, however, the indication of
HFOV is limited because of the risk of barotrauma and air-trapping. A very limited number of adult cases withobstructive respiratory failure successfully treated with HFOV have been reported. We present an adult case ofobstructive respiratory failure due to bronchiolitis obliterans in which HFOV was effective as ventilatory
management.
A 78-year-old male with bronchiolitis obliterans complicated by paraneoplastic pemphigus developed respiratory
failure with severe hypercapnia, and eventually required mechanical ventilation. Conventional mechanical ventilation
yielded a limited improvement in hypercapnia and acidemia because of severe airway obstruction. After initiating
HFOV, however, hypercapnia, acidemia and impaired consciousness markedly improved. With the administrationof methylprednisolone（1,000mg/body），the patient was weaned from HFOV and discharged without ventilatory
support. In conclusion, HFOV appears useful for selected adult patients with obstructive pulmonary disease.

there were reports of pediatric obstructive respiratory

Introduction

failure successfully treated with HFOV 4), few reports

High-frequency oscillatory ventilation (HFOV) ison adult cases have been found in the literature.

one of the lung-protective ventilatory modes thatBronchiolitis obliterans with paraneoplastic pemp­

rapidly delivers small tidal volumes with high mean

higus is a life-threatening disease, frequently compli­

airway pressures (MAP), decreasing the shear stresscated by non-Hodgkin lymphoma, chronic lymphocyticon alveoli . The beneficial effects of HFOV in adult andleukemia and Castleman disease 5). Respiratory impair­

pediatric cases with severe respiratory failure havement is the leading cause of death, and the mortality

been demonstrated. However, because of the risk

rate is estimated at appro­ximately 90% 6). We presentof barotrauma or air-trapping, the indication of HFOVan adult patient with severe obstructive respiratory

is limited in patients with severe obstruc­tive pulmonary

failure due to bron­chiolitis obliterans with paraneoplastic

diseases such as emphysema or asthma . Although

pemphigus who was successfully treated with HFOV.

1)

1, 2)

3)

Department of Emergency and Critical Care Medicine,
Graduate School of Biomedical Sciences, Hiroshima University［Received September 15, 2011：Accepted May 29, 2012］

Case Report
A 78-yr-old male visited the outpatient clinic of the人工呼吸

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Web 版［公開日：2012 年 7 月 23 日］（B）

Fig. 1 （A）Chest radiograph showing bilateral hyperinflation.（B）Chest computed tomography showing
a newly emerged ground-glass attenuation corresponding to air-trapping in bilateral lung fields.

department of dermatology of Hiroshima University

tomography (CT) demonstrated newly emerged diffuse

Hospital in October 2008 complaining of systemic

air-trapping (Fig. 1). The patient was hypotensive withblistering. He was diagnosed as having plasmacytoma

systemic blood pressure of 90mmHg. Laboratory find­complicated by paraneoplastic pemphigus, and started

ings showed leukocytosis (WBC : 12,270/μL, neutrophil :on oral corticosteroids.

84%), anemia (hemoglobin : 7.8g/dL), and an increase

In April 2009, he presented with dyspnea characte­in C-reactive protein (1.11mg/dL). However, there

rized by a mild prolongation of expiration. Radiologicalwere no elevation of procalcitonin and β-D-glucan

findings of the chest showed bilateral pulmonary

levels, and no symptoms of cardiac failure.

overdistention. He was diagnosed as having bron­chiolitis

Based on these findings, this patient was diagnosed

obliterans, and treated with a higher dose of oral

as having acute exacerbation of bronchiolitis oblite­rans.

corticosteroids and bronchodilators and transient

Because of his impaired level of consciousness, he wasimprovement of the symptoms were observed.

intubated and initially ventilated with conventional

In January 2010, his respiratory symptoms graduallymechanical ventilation (CMV). Although we used aworsened, resulting in hypercapnia and impaired

volume-controlled ventilation with a small tidal volumeconsciousness. He was admitted to the intensive careof 350mL (6 mL/kg) to avoid alveolar hyperinflation,unit for ventilatory support.

MAP was estimated above 25cmH2O and the inspira­The patient’s height and weight were 163cm andtory peak, plateau and end-inspiratory airway pressure

38kg. No obvious abnormality of the upper airway wasremained extremely high (>50cmH2O) (FIO2 0.4, respi­

found. However, he was tachypneic, and prolonged

ratory rate 18/min, positive end expiratory pressure

expiration and auscultatory attenuation of respiratory(PEEP) 5 cmH2O, inspiration-to-expiration ratio wassound were observed on ICU admission. Arterial blood

ranged from 1 : 2 to 1 : 4). The constant plateau pre­gas (ABG) analysis under 5 L/min oxygen with a facessure levels despite the increment of PEEP and themask demonstrated uncompen­sated respiratory acidosis

presence of end-expiratory airway flow suggested(pH 7.157, PaCO2 114mmHg, PaO2 124mmHg, base excess

the presence of auto-PEEP, which was estimated to(B.E.) 10.3mEq/L). A chest radiograph showed hyper­

be above 10cmH2O according to the procedure descri­

inflation in the bilateral lung field, and chest computed

bed by Marini et al. 7) ABG analysis obtained after the人工呼吸

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Methylprednisolone（1,000mg/body）
120

127.4

87.3

100
B.E.
（mEq/L）

PaCO280（Torr）

pH

4

7.20060
Initiation of HFOV01 2 3 4
Duration of ICU stay（days）
CMVFig. 2HFOV5CMVClinical course of the patient showing rapid improvement in hypercapnia after the initia­tion of HFOV. Closed circles indi­cate
PaCO2, closed squares indicate B.E., and open squares indicate pH. PaCO2, partial pressure of arterial carbon dioxide；B.E., baseexcess；HFOV, high-frequency oscillatory ventilation；CMV, conventional mechanical venti­lation.

initiation of CMV showed limited improvement instroke volume up to 285mL). Thereafter, we maintained

hypercapnia and acidemia (pH 7.24, PaCO2 92mmHg andthe same settings for the following 4 days in combination

B.E. 11mEq/L). Although we tried pressure-controlledwith methylprednisolone (1,000mg/body) and antibiotics.

ventilation with various PEEP settings and airway

The findings in ABG analyses, chest radiographs, andpressure release ventilation, the effective ventilatory

vital signs including blood pressure and heart rate

management was quite difficult because of the insu­

continued to improve. On day 5, the ventilator mode

fficient airway stenting or the extremely high airway

was switched back to CMV (pressure controlled- synch­pressure. The improve­ments in hypercapnia andronized intermittent mandatory ventilation (SIMV),

acidemia were limited, and the patient has become

FIO2 0.35, peak pressure 25cmH2O, PEEP 5 cmH2O,

more restless. Eventually, we switched to HFOV

respiratory rate 20/min, inspiration-to-expiration ratio(R100, Metran Co.,Ltd., Saitama, Japan) (FIO2 0.4, MAP

1 : 2) and the patient was smoothly weaned from the30cmH2O, frequency 10Hz, stroke volume 150mL, baseventilator. He was successfully extubated on day 23

flow 20L/min). We did not use muscle relaxants because

and discharged to the rehabili­tation center 4 months

the patient was very lethargic. The patient was sedated

later. No barotrauma was observed in this patient.

appropriately with 1 mg/hour of midazolam. Following
the initiation of HFOV, MAP became stable and noDiscussion

pulmonary injuries such as pneumothorax wereBronchiolitis obliterans complicated by paraneo­plastic

observed. The amplitude was decreased from 120cmH2O

pemphigus is a rare but potentially life-threatening

to 80cmH2O. ABG showed a marked improvement

disease due to severe obstructive respi­ratory failure 5).

(pH 7.33, PaCO2 65mmHg and B.E. 7.5mEq/L) (Fig. 2).

Dynamic air-trapping and a resultant barotrauma areWe gradually tapered the settings of HFOV based

the severe complications during ventilation that shouldon the ABG data and/or the amplitude monitoring

be avoided. Therefore, the monitorings of flow-volume

to minimize the risk of barotrauma and to avoid

curve and chest radio­graph are important.

acidemia (FIO2 0.3, MAP 18cmH2O, frequency 6 Hz,

A number of different mechanisms of gas transport人工呼吸第 29 巻

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Web 版［公開日：2012 年 7 月 23 日］

have been identified in HFOV 8). Sufficient high PEEP

underlying the successful use of HFOV in patientsin HFOV is advantageous for opening collapsed airways

with obstructive pulmonary disease.

and keeping them open throughout the entire respi­
ratory cycle without injurious peak airway pressures 9).
Because the peak and plateau airway pressures during
CMV were extremely high in our patient even when
considering the effect of panting, we did not try higher
PEEP for fear of barotrauma. The mechanisms ofReferences
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