[Child Health] Dr Peter Barry



RESEARCH INTERESTS

  1. My clinical interests are in paediatric respiratory medicine and intensive care, and I have published a number of articles on inhalational drug delivery and the provision of paediatric intensive care facilities.
  2. I also have an interest in high altitude medicine and physiology, particularly in respiratory function and respiratory defenses at altitude

CURRENT PROJECTS/GRANTS

Inhalational Drug Delivery

During studies for my PhD thesis, entitled 'Problems with Inhalational Drug Delivery to Children', a multi-faceted in vitro study of inhalational devices and drugs, I have established, with Dr C O'Callaghan, an aerosol laboratory that can now perform a rapid and thorough analysis of inhalational drug delivery devices, both in vitro and in vivo.

We use various inertial and laser diffraction based particle sizing techniques; high speed video to record aerosol cloud speed and geometry; piston based devices to mimic breathing patterns during the use of inhalational therapy devices; computerised breathing simulators to record breathing patterns and replay them through particle sizing devices; High performance liquid chromatography and spectrophotometric assays of all major inhalational drugs have been adapted or developed in our laboratory. We have also developed methods for measuring static charge on spacers and other drug delivery devices.

We have undertaken a number of studies highlighting differences in the output of drug from inhalational drug delivery devices. It is not widely appreciated that the correct choice of device, and its optimal use, may improve drug delivery by 200%.

Paediatric Intensive Care

Despite recent media interest in paediatric intensive care, there is very little information on the use of hospital facilities by critically ill children in the United Kingdom. In 1992 I undertook a review of paediatric admissions to intensive care facilities in and around Birmingham. Details of over a thousand admissions were collected, and allowed population based information on the use of intensive care facilites to be derived for the first time in the UK. This study demonstrated the large seasonal variation in intensive care use by children, highlighting the dangers in planning intensive care provision on the basis of short term studies.

There has also been recent debate on the merits of centralisation of paediatric intensive care facilities. I co-ordinated the UK part of a large comparative trial of intensive care outcome initiated by Dr Gale Pearson. The trial compared severity of illness adjusted mortality in Victoria, Australia, which has a centralised paediatric intensive care facility, with the Trent region, which has a more disparate provision. This collected data on over one thousand admissions of children to intensive care facilities in Trent during 1994-95.

Increasing centralisation of intensive care will mean that more critically ill children are transferred between hospitals. In 1992 I undertook a prospective study of critical incidents that occurred during the transfer of children to the intensive care unit of Birmingham Children's Hospital. The study revealed a large number of potentially serious errors and ommisions that occurred during the transfers.

High Altitude Medicine
A high altitude laboratory

In the autumn of 1994 I spent two months in Nepal as part of the British Mount Everest Medical Expedition, investigating respiratory defence systems and lung function at altitude.

Many climbers complain of cough and rhinorhorrea at altitude. The cough can be debilitating, and here have been a number of documented cases of rib fractures occurring in climbers after coughing spasms. Furthermore the initiation and control of cough are poorly understood, but may be related to factors affecting the control of breathing. My main project was to study the frequency of cough, and the sensitivity of cough receptors at altitude. This involved making recordings of cough at altitudes up to 7,000 meters, and undertaking the world's highest inhalational cough challenges, at 5,300m.

The results of the study demonstrated a dramatic increase in cough and cough receptor sensitivity at altitude, and an relationship between changes in cough receptor sensitivity and the hypercapnic ventilatory response, suggesting a possible link between cough and the control of breathing.

With Dr Nick Mason I also undertook an investigation of heart rate variability at altitude. We used portable loggers to record electrocardiograms during acclimatisation to up to 8,000m. During acclimatisation the autonomic nervous system is adjusted, with 'down regulation' of the sympathetic nervous system. Using techniques such as spectral analysis, the electrocardiograms give an indication of sympathetic and parasympathetic tone, and our recordings allow us to document changes in the autonomic nervous system during the hypobaric hypoxia experienced at altitude. Such techniques have also been used to investigate autonomic function in diabetes and the newborn.

With Dr Andrew Pollard and colleagues, I also participated in a study looking at the use of different peak flow meters and changes in spirometry at altitude. We demonstrated that variable orifice peak flow meters, such as the mini-Wright peak flow meter, are inaccurate, and that 'true' peak flow rises on ascent to altitude. These changes are thought to be due to changes in air density at altitude.

I recently participated in 'Operation Everest - Comex', a two month study undertaken in a hypobaric chamber in Marseille. Eight subjects 'ascended' to a height equal to the summit of Mount Everest while undertaking a number of scientific project. I was involved in experiments looking at the cough reflex and spirometry.

Further research is planned for next year on an expedition organised by Medical Expeditions. Details from their home page.


Publications

Aerosols and Inhalational Therapy

  1. Barry PW, O'Callaghan C. 'Inhaler Devices for Pre-school Children' Paediatric Respiratory Medicine 1993;1 (3):20-3.
  2. Barry PW, O'Callaghan C. 'Inhaled Steroid Therapy'. Current Paediatrics 1994;4:114-7.
  3. Barry PW, O'Callaghan C. Therapeutic aerosols. Medicine 1995;23(7):270-3
  4. Barry PW, O'Callaghan C. Asthma Inhalers. Medicine in Practice 1995;2(3):14-15
  5. O'Callaghan C, Barry PW. Inhalation devices for young children. Paediatric and Perinatal Drug Therapy 1997;1:59-65.
  6. Barry PW, O'Callaghan C. Nebuliser therapy in childhood. Thorax 1997;52 (supp 2):S78-88.
  7. O'Callaghan C, Barry PW. The science of nebulised drug delivery. Thorax 1997;52 (supp 2):S31-44.
  8. Barry PW, Robertson C, O'Callaghan C. 'Optimum use of a spacer device' Archives of Disease in Childhood 1993;69:693-4.
  9. Barry PW, O'Callaghan C. Multiple actuations of salbutamol metered dose inhaler into a spacer device reduce the amount of drug recovered in the respirable range. European Respiratory Journal 1994;7:1707-9.
  10. Barry PW, O'Callaghan C. The effect of delay, multiple actuations and spacer charge on the in vitro delivery of budesonide from the Nebuhaler. British Journal of Clinical Pharmacology 1995;40:76-8.
  11. Barry PW, O'Callaghan C. Video analysis of the aerosol cloud produced by metered dose inhalers. Pharmaceutical Science 1995;1:119-21.
  12. Barry PW, O'Callaghan C. Inhalational Drug Delivery From Seven Different Spacer Devices. Thorax 1996;51:835-40.
  13. O'Callaghan C, Barry PW. Spacer devices in the treatment of asthma. British Medical Journal 1997;314:1061-2.
  14. Barry PW, O'Callaghan C. In vitro comparison of the amount of salbutamol available for inhalation from different formulations used with different spacer devices. European Respiratory Journal 1997;10:1345-8.

Paediatric Intensive Care

  1. Barry PW, Hocking MD. Paediatric use intensive care. Archives of Disease in Childhood 1994;70:391-4.
  2. Barry PW, McLellan NJ, Hocking MD. Intensive Care for Children in a District General Hospital. Care of the Critically Ill 1994;10:108-12.
  3. Barry PW, Ralston C. Adverse events occurring during inter-hospital transport of the critically ill. Archives of Disease in Childhood 1994;71:8-11.
  4. Barry PW, Hocking MD. Children in intensive care - why and where? British Journal of Intensive Care 1995;5(7):227-32
  5. Pearson G, Shann F, Barry PW, Powell C, Vyas J, Thomas D, Field D. Should paediatric intensive care be centralised? Trent versus Victoria. Lancet 1997;349:1213-17.

High Altitude Medicine and Physiology

  1. Pollard AJ, Mason NP, Barry PW, Pollard RC, Collier DJ, Fraser RS, Miller MR, Milledge JS. Effect of altitude on spirometric parameters and the performance of peak flow meters. Thorax 1996;51:175-8.
  2. Barry PW. The effects of mountaineering on human physiology. Biological Sciences Review 1996;8:19-24.
  3. Barry PW, Mason NP, O'Callaghan C. Nasal muco-ciliary transport is impaired at altitude. European Respiratory Journal. 1997;10:35-7.
  4. Pollard AJ, Mason NP, Barry PW, Collier DJ, Pollard RC, Fraser RS, Miller MR, Milledge JS. Hypoxia, Hypocapnia and spirometry at altitude. Clinical Science 1997;92:593-8.
  5. Barry PW, Mason NP, Riordan M, O'Callaghan C. Cough at altitude. Clinical Science 1997;93:181-6.

Others

  1. Ong G, Atherton M, Karim K, Langton J, O'Callaghan C, Barry PW. Neonatal Cilia and Halothane. J Paediatr Child Health 1994;30:429-31.
  2. O'Callaghan C, Achaval M, Forsythe I, Barry PW. Brain and respiratory cilia: the effect of temperature. Biology of the Neonate. 1995;68:394-7.

Abstracts

  1. Barry PW. Combined unheated transcutaneous pCO2 and pulse oximetry. (abstract). Clinical and investigative medicine 1990;13(4):B108
  2. Barry PW, Hocking MD. Audit of paediatric use of intensive care in a district general hospital. (abstract). Care of the Critically Ill 1993;9:38.
  3. Barry PW, Hocking MD. How Many Children Use Intensive Care Facilities? (abstract) Care of the Critically Ill 1994;10:89.
  4. Barry PW, Hocking MD. Children in intensive care - why and where? (abstract) Care of the Critically Ill 1994;10:175.
  5. Barry PW, O'Callaghan C. Poor Output of Salbutamol from a spacer device: effect of spacer static charge and multiple actuations. (abstract) Thorax 1994;49:402P
  6. Barry PW, O'Callaghan C. The optimum size and shape of spacer devices for inhalational therapy (abstract). Journal of Aerosol Medicine. 1995;8(3):303-5.
  7. Barry PW, O'Callaghan C. The optimum size and shape of spacer devices for inhalational therapy (abstract). Conference Proceedings, Drug delivery to the lungs V. The Aerosol Society, Bristol, UK.
  8. Barry PW, O'Callaghan C. The effect of delay, multiple actuations and spacer static charge on the delivery of budesonide from the Nebuhaler (abstract). Journal of Aerosol Science (in press)
  9. Barry PW, O'Callaghan C. The effect of delay, multiple actuations and spacer static charge on the delivery of budesonide from the Nebuhaler (abstract). Conference Proceedings, Ninth Annual Conference, 1994; 216-20. The Aerosol Society, Bristol, UK.
  10. Barry PW. Mason NP, Collier DJ. Sex differences in blood gases at altitude (Abstract). In Hypoxia and the Brain eds. Sutton JR, Houston CS, Coates G. CS Houston, Burlington, USA. 1995, p330.
  11. Pollard AJ, Mason NP, Barry PW, Pollard RC, Fraser RS, Collier DJ, Milledge JS. Changes in spirometry at altitude (Abstract). In Hypoxia and the Brain eds. Sutton JR, Houston CS, Coates G. CS Houston, Burlington, USA. 1995, p334.
  12. Mason NP, Pollard AJ, Barry PW, Pollard RC, Collier DJ, Milledge JS. Spirometry and chronic hypoxia (Abstract). In Hypoxia and the Brain eds. Sutton JR, Houston CS, Coates G. CS Houston, Burlington, USA. 1995, p330.
  13. Barry PW, O'Callaghan C. The level of static charge on spacer devices used with inhalational drugs. Paediatric reviews and communications, 1995;8:210
  14. Barry PW, O'Callaghan C. High speed video analysis of the aerosol cloud produced by metered dose inhalers. (Abstract). Journal of Aerosol Medicine 1995; 8(1):88.
  15. Barry PW, Jackson J, O'Callaghan C. An assessment of different impingers in particle size determination of therapeutic aerosols. (Abstract). Journal of Aerosol Medicine 1995; 8(1):88.
  16. Barry PW, Mason NP, O'Callaghan C. Muco-ciliary clearance in humans at altitude. (Abstract). Journal of Physiology 1995;487:106P
  17. Barry PW, Johnson P, O'Callaghan C. Variable delivery of salbutamol from generic metered dose inhalers using the Volumatic spacer device. (Abstract). European Respiratory Journal. 1995;8 (supp 19):13s
  18. Barry PW, Jackson J, O'Callaghan C. The effect of delay on the delivery of salbutamol from two spacer devices. (Abstract). European Respiratory Journal. 1995; 8 (supp 19):70s
  19. Barry PW, Mason NP, Riordan M, O'Callaghan C. Changes in cough sensitivity at altitude (Abstract). Thorax 1995;50 (suppl 2):A33
  20. Pollard AJ, Barry PW, Mason NP, Collier DJ, Pollard RC, Pollard PFA, Fraser RS, Miller MR, Milledge JS. Hypoxia, hypocapnia and spirometry at altitude (Abstract). Thorax 1995;50 (suppl 2):A61
  21. Mason NP, Pollard AJ, Barry PW, Pollard RC, Collier DJ, Fraser RS, Miller MR, Milledge JS. Changes in spirometry at altitude (Abstract). Thorax 1995;50 (suppl 2):A67
  22. Barry PW, O'Callaghan C. The use of the chlorofluorocarbon free salbutamol preparation, Airomir, with different spacer devices (Abstract). Thorax 1995;50 (suppl 2):A78
  23. Barry PW, O'Callaghan C. The output of budesonide from nebulisers. (Abstract). Conference proceedings, Drug Delivery to the lungs VI. Bristol, The Aerosol Society, 1995, p98-101.
  24. Barry PW, Mason NP, Nickol A, Datta A, Milledge JS, Wolff CB, Collier DJ. Cough Receptor sensitivity and dynamic ventilatory response to carbon dioxide in man acclimatised to high altitude (Abstract). Journal of Physiology (in press).
  25. Barry PW, O'Callaghan C. The output of drug from the syncroner open spacer. Conference proceedings, Drug Delivery to the Lungs VII. Bristol, The Aerosol Society, 1996, p111-114.
  26. Barry PW, Mason NP, Nickol A, Datta A, Milledge JS, Wolff CB, Collier DJ. Cough Receptor sensitivity and dynamic ventilatory response to carbon dioxide in man acclimatised to high altitude(Abstract). In Hypoxia eds. Houston CS, Coates G. CS Houston, Burlington, USA.(in press)
  27. Barry PW, Mason NP, O'Callaghan C. Inspiratory flow at altitude (Abstract). In Hypoxia eds. Houston CS, Coates G. CS Houston, Burlington, USA.(in press)
  28. Barry PW, O'Callaghan C. The output of budesonide from different nebulisers. American Journal of Respiratory and Critical Care Medicine 1997; 155 (4 pt2):A671.
  29. Barry PW, O'Callaghan C. The output of salbutamol from spacer devices. American Journal of Respiratory and Critical Care Medicine 1997; 155 (4 pt2):A671.

Journal Letters

  1. Barry PW, Hocking MD. Neonatal rib fracture - birth trauma or non accidental injury? (letter). Archives of Disease in Childhood 1993;68:250.
  2. Barry PW. Provision of Paediatric Intensive Care. (letter). British Medical Journal 1993;307:1424 (27 November).
  3. Barry PW. Mason NP, Collier DJ. Everest study supports use of capillary sampling (letter). British Medical Journal 1995;310:1072.
  4. Barry PW, O'Callaghan C. Emergency Treatment of Asthma. Thorax 1995;
  5. Barry PW, O'Callaghan C. Inhalational Drug Delivery From Seven Different Spacer Devices. Thorax 1997;52:586.
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