Reducing the Risk of Pulmonary Barotrauma

Reducing the Risks of Pulmonary Barotrauma

Medical Factors

History
The same conditions that cause spontaneous pneumothorax can be deadly in the increased ambient pressures of diving - and even in the pressure changes that take place in pressurized aircraft. Awareness of these conditions that can lead to spontaneous pneumothorax might aid in the reduction of the risk of 'burst lung' and cerebral arterial gas embolism.

Some of these conditions and diseases include:

Asthma, COPD, mucoviscidosis (cystic fibrosis), Pneumocystis carinii, tb, bronchiolitis (smokers), viral lower airway disease, HIV infection, bronchial atresia, sports blunt trauma, weight lifting, metastatic tumors, catamenia (perimenstrual), empyema, bullous emphysema (juvenile, apical, generalized), Marfan's syndrome, Schistosome infestation, Pregnancy, cryptogenic fibrosing alveolitis, and pulmonary histiocytosis X, Congenital bronchopulmonary cystic disease, vibroacoustic disease, alveolar proteinosis, bronchiectasis

     Symptoms of emphysema include:
     Cough
     Wheezing
     Shortness of breath
     Blue or pink discoloration of the nail beds or lips (blue bloater or pink puffer)
     Smoking
     Exposure to chemical or commercial agents

Examination

         Prolonged expiratory phase in breathing
         Audible wheezing and rhonchi (rattles)
         Auscultatory rales (stethoscope findings by the physician)
         Increased AP diameter chest
         Clubbing (fingernails rounded and tips of fingers widened)
         Nail bed and lip color changes
         Percussive changes in the lung fields (tonal reverberations)

Studies

        Spiral (helical) CT (probably the best to rule out pulmonary blisters)
         Chest x-ray
         Pulmonary functions
          Lung scan
          Xe-CT ventilation studies
          Forced Expiratory Volume
          Computer-Assisted MT
          Maximal Midexpiratory Flow Rate
          Tomography, X-Ray Computed
          Vital Ca pacity
          Body plethysmography
          spirometry
          metacholine airway provocation.

Diver Factors

Awareness of cause of problem (ascending from depth with a closed air-containing chamber)
Gear failure
Breath holding on ascent
'Sipping' from a regulator by a free diver
Weight lifting from depth
Boat exits in heavy wave action
-ascend anchor line for stability
-continue to breathe via regulator until you are out of the water
Straining while removal of gear (fins, weight belt) in the water
Poor air management, avoid running out of air
Panic ascents
Faulty buddy breathing practices

References and abstracts for Spiral CT scan

Title
     Air trapping on expiratory high-resolution CT scans in the absence of inspiratory scan
     abnormalities: correlation with pulmonary function tests and differential diagnosis.
Author Arakawa H; Webb WR
Address Department of Radiology, University of California, San Francisco 94143-0628, USA.
Source AJR Am J Roentgenol, 170(5):1349-53 1998 May
Abstract
     OBJECTIVE: We wish to describe the differential diagnosis and pulmonary function
     correlates of patients with normal findings on inspiratory high-resolution CT (HRCT) scans
     who showed air trapping on expiratory scans. CONCLUSION: Air trapping on expiratory HRCT scans in patients with normal findings on inspiratory scans is most often associated with bronchiolitis obliterans and asthma. Obtaining expiratory scans in patients who may have one of these diseases recommended.

Title Preoperative and postoperative imaging in the surgical management of pulmonary
     emphysema.
Author
     Slone RM; Gierada DS; Yusen RD
Address
     Mallinckrodt Institute of Radiology, Barnes-Jewish Hospital, Washington University School of
     Medicine, St. Louis, Missouri, USA.
Source
     Radiol Clin North Am, 36(1):57-89 1998 Jan
Abstract
     For patients with emphysema, imaging studies have been useful for diagnostic purposes and for
preoperative patient selection for surgical intervention, such as bullectomy, lung transplantation,
and LVRS. Chest radiography is useful in evaluating hyperinflation. Inspiratory and expiratory
films are used to estimate diaphragmatic excursion and air-trapping. CT scan is used to evaluate the anatomy and distribution of emphysema throughout the lungs, providing information clinically unobtainable by other means. Both imaging techniques are useful for detecting other disease processes. Radionuclide lung scanning also provides an estimate of target areas, volume occupying but nonfunctioning lung. Cohort studies utilizing these imaging techniques have demonstrated associations between preoperative characteristics and postoperative outcome. The imaging studies, especially the chest radiograph, have also played an important role in postoperative management. Many other imaging options are available, such as HRCT scan, quantitative CT scan, and single photon emission CT scan. Other techniques, such as MR imaging, may play a future role as well.

    Title [Dynamic computed tomography in the study of bronchiolitis obliterans]
Author
     Zompatori M; Poletti V; Battista G; Canini R; Bruscoli P; Carfagnini F
Address
     Radiologia Padiglione Pneumonefrologico, Policlinico S. Orsola-Malpighi, Bologna.
Source
     Radiol Med (Torino), 94(4):308-14 1997 Oct
Abstract
     Obliterative or constrictive bronchiolitis is characterized by narrowing of the small airways, due
to submucosal and peribronchiolar fibrosis, with chronic obstruction. The vast majority of cases
of bronchiolitis obliterans are associated with other diseases and only few cases are idiopathic.
We report on the main computed tomography (CT) methods used study obliterative
bronchiolitis, the CT findings and the differential diagnosis with other diseases. The combination of HRCT, rapid volumetric scanning and advanced image display is a powerful tool study the normal and abnormal features of bronchiolar function and alveolar ventilation.

    Title Expiratory CT scans for chronic airway disease: correlation with pulmonary function test
     results.
Author
     Lucidarme O; Coche E; Cluzel P; Mourey-Gerosa I; Howarth N; Grenier P
Address
     Department of Radiology, Universit´e Pierre et Marie Curie, H^opital de la Piti´e-Salp^etri`ere,
     Paris, France.
Source
     AJR Am J Roentgenol, 170(2):301-7 1998 Feb
Abstract
     OBJECTIVE: The purpose of our study was to correlate findings on expiratory CT scans with
     results of pulmonary function tests (PFTs) and to determine whether these techniques may be
     complementary in assessing airway obstruction.
CONCLUSION: Air trapping may permit detection of airway obstruction in patients with
     clinically suspected chronic airway disease even when PFTs are normal. Furthermore,
     expiratory CT allows one to calculate a reduction score for a cross-sectional lung area that
     appears to be better correlated with the degree of airway obstruction measured on PFTs.

Title
     Air trapping in children: evaluation with dynamic lung densitometry with spiral CT.
Author
     Johnson JL; Kramer SS; Mahboubi S
Address
     Department of Radiology, Children's Hospital of Philadelphia, PA 19104, USA.
Source
     Radiology, 206(1):95-101 1998 Jan
Abstract
     PURPOSE: To evaluate the feasibility of the use of a simple method of dynamic lung
     densitometry with spiral computed tomography (CT) to differentiate air trapping from
     compensatory hyperinflation in children.
CONCLUSION: Dynamic spiral CT lung densitometry is a quick, simple method for quantitative confirmation of the presence of air trapping and differentiation from compensatory hyperinflation.

Title
     [Quantitative assessment of pulmonary emphysema with computerized tomography.
     Comparison of the visual score and high resolution computerized tomography, expiratory density mask with spiral computerized tomography and respiratory function tests]
Author
     Zompatori M; Battaglia M; Rimondi MR; Fasano L; Cavina M; Pacilli AM; Guerrieri A; Fabbri
     M; Vivacqua D; Biscarini M
Address
     Radiologia padiglione Pneumonefro, Policlinico S. Orsola-Malpighi, Bologna.
Source
     Radiol Med (Torino), 93(4):374-81 1997 Apr
Abstract
     CT is the most accurate method to detect pulmonary emphysema in vivo.

Title
     Quantitative chest computed tomography as a means of predicting exercise performance in
     severe emphysema.
Author
     Crausman RS; Ferguson G; Irvin CG; Make B; Newell JD Jr
Address
     Department of Medicine, National Jewish Center for Immunology and Respiratory Medicine,
     Denver, CO 80206, USA.
Source
     Acad Radiol, 2(6):463-9 1995 Jun
Abstract
     RATIONALE AND OBJECTIVES: We assessed the value of quantitative high-resolution
     computed tomography (CT) as a diagnostic and prognostic tool in smoking-related emphysema.

CONCLUSION: Quantitative chest CT assessment of disease severity is correlated with the
degree of airflow limitation and exercise impairment in pulmonary emphysema.

Title
     Spiral computed tomographic scanning of the chest with three dimensional imaging in the diagnosis and management of paediatric intrathoracic airway obstruction.
Author
     Sagy M; Poustchi-Amin M; Nimkoff L; Silver P; Shikowitz M; Leonidas JC
Address
     Division of Critical Care Medicine, Schneider Children's Hospital, Long Island Jewish Medical
     Center, New Hyde Park, NY 11042, USA.
Source
     Thorax, 51(10):1005-9 1996 Oct
Abstract
     BACKGROUND: The usefulness of spiral computed tomographic (CT) scans of the chest
     with three dimensional imaging (3D-CT) of intrathoracic structures in the diagnosis and
     management of paediatric intrathoracic airway obstruction was assessed.
CONCLUSIONS: 3D-CT scanning is a useful additional diagnostic tool for
     intrathoracic airway obstruction in paediatric patients.

Title
     Thin-section CT detection of emphysema associated with bronchiectasis and correlation with
     pulmonary function tests.
Author
     Loubeyre P; Paret M; Revel D; Wiesendanger T; Brune J
Address
     Service de Radiologie, Hopital Cardiovasculaire et Pneumologique, Lyon, France.
Source
     Chest, 109(2):360-5 1996 Feb
Abstract
     PURPOSE: To evaluate, on thin-section CT scans, the prevalence of emphysema in patients
     with bronchiectasis and to correlate the results of thin-section CT scans with the results of
     pulmonary function tests, in order to question whether there was a particular functional test
     profile in this group of patients.
     CONCLUSION: Our series suggests that there is a high prevalence of emphysema in patients
     with bronchiectasis. Emphysema that was not suggested using pulmonary function tests in
     most of the cases could explain in part the higher airway obstruction observed in the group of
     patients with CT evidence of emphysema. This study could support the suggestive notion that
     emphysema, which was mainly localized in bronchiectatic lobes, could be due to the
     inflammatory airway process.

Title
     Airway obstruction in asthmatic and healthy individuals: inspiratory and expiratory thin-section
     CT findings.
Author
     Park CS; M¨uller NL; Worthy SA; Kim JS; Awadh N; Fitzgerald M
Address
     Department of Radiology, University of British Columbia and Vancouver Hospital and Health
     Sciences Centre, Canada.
Source
     Radiology, 203(2):361-7 1997 May
Abstract
     PURPOSE: To determine differences in computed tomographic (CT) findings in asthmatic and
     healthy individuals and to correlate the findings with severity of airway obstruction.
      CONCLUSION:
     Thin-section CT is of limited value in distinguishing asthmatic patients with normal airflow or
     mild airflow obstruction from healthy subjects.

Title
     Radiology of pulmonary emphysema and lung volume reduction surgery.
Author
     Slone RM; Gierada DS
Address
     Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, MO
     63110, USA.
Source
     Semin Thorac Cardiovasc Surg, 8(1):61-82 1996 Jan
Abstract
     Lung volume reduction surgery (LVRS), which involves the bilateral wedge resection of 20%
to 30% of the most diseased lung through a median sternotomy, is emerging as a promising
treatment option for select patients with severe, debilitating emphysema. This article details our
observations and preliminary investigations related to the imaging evaluation of patients
including selection criteria, postoperative findings, and structural changes in the thorax after surgery.

Title
     Quantification of pulmonary emphysema from lung computed tomography images.
Author
     Uppaluri R; Mitsa T; Sonka M; Hoffman EA; McLennan G
Address
     Department of Electrical and Computer Engineering, University of Iowa, Iowa City 52242,
     USA.
Source
     Am J Respir Crit Care Med, 156(1):248-54 1997 Jul
Abstract
     A texture-based adaptive multiple feature method (AMFM) for evaluating pulmonary
     parenchyma from computed tomography (CT) images is described. Quantitative texture analysis using adaptive
     multiple features holds promise for the objective noninvasive evaluation of the pulmonary
     parenchyma.

Title
     Normal pulmonary geometric changes due to respiration: evaluation with inspiratory and
     expiratory spiral CT.
Author
     Wang Q; Takashima S; Sone S; Maruyama Y; Hasegawa M
Address
     Department of Radiology, Shinshu University School of Medicine, Matsumoto, Japan.
Source
     Radiat Med, 16(4):257-62 1998 Jul-Aug
Abstract
     RATIONALE AND OBJECTIVES: To investigate the pattern of physiological pulmonary
     geometric changes in the longitudinal direction due to respiration. CONCLUSION: We have described the normal longitudinal displacement patterns of the pulmonary structures due to respiration. These findings may be applied to the diagnosis of pulmonary diseases.

Title
     [Spontaneous pneumothorax in young women: possible lymphangioleiomyomatosis]
Author
     Louis H; Los H; Lagendijk JH; de Graaff CS; Postmus PE
Address
     Afd. Interne Geneeskunde, Academisch Ziekenhuis Vrije Universiteit, Amsterdam.
Source
     Ned Tijdschr Geneeskd, 141(40):1924-8 1997 Oct 4
Abstract
     (Recurrent) pneumothorax developed spontaneously in three women aged 33, 35 and 36 years, two of whom were pregnant. Treatment consisted in drainage of the pneumothorax, pleurodesis and pleurectomy, with administration of medroxy-progesterone. One year later, the pneumothorax had not recurred.

Title
     [Usefulness of computed tomography and scintigraphy in diagnosis of emphysematous bullae in the lung]
Author
     Furman M; Kozlowski M; Szulc S; Rogowski F; Gulaj C; Bernacki A; Cybulski A
Address
     Kliniki Chirurgii Klatki Piersiowej, Bialymstoku.
Source
     Wiad Lek, 50(7-9):156-62 1997
Abstract
     The x-ray examinations usually do not reveal morbid changes after lung expansion in the
     treatment of spontaneous pneumothorax. In our observation computed tomography (CT) and
     scintigraphy enable not only the exact determination of the extent of changes but also they
     disclose bullae invisible in conventional chest radiographs.
CONCLUSION: CT is a method of choice in the diagnosis of lung emphysematous bullae and it enables the detection of the changes undetectable in chest radiographs. Perfusion and inhalation scintigraphy is helpful in the diagnosis of large emphysematous bullae and postoperative follow-up examination.

Title
     Contribution of emphysema and small airways in COPD.
Author
     Gelb AF; Hogg JC; M¨uller NL; Schein MJ; Kuei J; Tashkin DP; Epstein JD; Kollin J; Green
     RH; Zamel N; Elliott WM; Hadjiaghai L
Address
     Department of Medicine, Lakewood Regional Medical Center, School of Medicine, CA, USA.
Source
     Chest, 109(2):353-9 1996 Feb
Abstract
     BACKGROUND: The contribution and role of emphysema and small airways disease in
     causing expiratory airflow limitation in COPD is controversial. CONCLUSIONS: High-resolution CT lung scans are an in vivo surrogate to quantitate moderate to severe morphologic emphysema. Emphysema does not appear to be primarily responsible for severe expiratory airflow limitation in most patients with severe COPD. There was no correlation between severity of small airway histologic condition and emphysema or FEV1 percent predicted. The causes of the lesions responsible for small airways obstruction need to be identified.

Title
     [Detection of emphysematous bullae in spontaneous pneumothorax by three-dimensional computed topography]
Author
     Yusa T; Iyoda A
Address
     Department of Respiratory Surgery, Chiba Rosai Hospital, Japan.
Source
     Nihon Kokyuki Gakkai Zasshi, 36(8):722-5 1998 Aug
Abstract
     The patient was a 20-year-old woman with spontaneous pneumothorax, who had had
     pneumothorax twice on each side. This suggests that three-dimensional CT is a useful method for diagnosing and evaluating emphysematous bullae in patients with spontaneous pneumothorax.