Moderate concentrations of supplemental oxygen worsen hypercapnia in obesity hypoventilation syndrome: A randomised crossover study

Carly A. Hollier, Alison R. Harmer, Lyndal J. Maxwell, Collette Menadue, Grant WILLSON, Gunnar Unger, Daniel Flunt, Deborah A. Black, Amanda J. Piper

Research output: Contribution to journalArticle

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Abstract

Introduction In people with obesity hypoventilation syndrome (OHS), breathing 100% oxygen increases carbon dioxide (PCO2), but its effect on pH is unknown. This study investigated the effects of moderate concentrations of supplemental oxygen on PCO2, pH, minute ventilation (VE) and physiological dead space to tidal volume ratio (VD/VT) among people with stable untreated OHS, with comparison to healthy controls. Methods In a double-blind randomised crossover study, participants breathed oxygen concentrations (FiO2) 0.28 and 0.50, each for 20 min, separated by a 45 min washout period. Arterialised-venous PCO2 (PavCO2) and pH, VE and VD/VT were measured at baseline, then every 5 min. Data were analysed using general linear model analysis. Results 28 participants were recruited (14 OHS, 14 controls). Among OHS participants (mean±SD arterial PCO2 6.7±0.5 kPa; arterial oxygen 8.9±1.4 kPa) FiO2 0.28 and 0.50 maintained oxygen saturation 98-100%. After 20 min of FiO2 0.28, PavCO 2 change (¿PavCO2) was 0.3±0.2 kPa (p=0.013), with minimal change in VE and rises in VD/VT of 1±5% (p=0.012). F iO2 0.50 increased PavCO2 by 0.5±0.4 kPa (p=0.012), induced acidaemia and increased VD/VT by 3±3% ( p=0.012). VE fell by 1.2±2.1 L/min within 5 min then recovered individually to varying degrees. A negative correlation between ¿VE and ¿PavCO2 (r=-0.60, p=0.024) suggested that ventilatory responses were the key determinant of PavCO2 rises. Among controls, FiO2 0.28 and 0.50 did not change PavCO2 or pH, but FiO2 0.50 significantly increased VE and VD/VT. Conclusion Commonly used oxygen concentrations caused hypoventilation, PavCO2 rises and acidaemia among people with stable OHS. This highlights the potential dangers of this common intervention in this group.
Original languageEnglish
Pages (from-to)346-353
Number of pages8
JournalThorax
Volume69
Issue number4
DOIs
Publication statusPublished - 2014

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Obesity Hypoventilation Syndrome
Hypercapnia
Cross-Over Studies
Ventilation
Oxygen
Hypoventilation
Tidal Volume
Carbon Dioxide
Linear Models
Respiration

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Hollier, C. A., Harmer, A. R., Maxwell, L. J., Menadue, C., WILLSON, G., Unger, G., ... Piper, A. J. (2014). Moderate concentrations of supplemental oxygen worsen hypercapnia in obesity hypoventilation syndrome: A randomised crossover study. Thorax, 69(4), 346-353. https://doi.org/10.1136/thoraxjnl-2013-204389
Hollier, Carly A. ; Harmer, Alison R. ; Maxwell, Lyndal J. ; Menadue, Collette ; WILLSON, Grant ; Unger, Gunnar ; Flunt, Daniel ; Black, Deborah A. ; Piper, Amanda J. / Moderate concentrations of supplemental oxygen worsen hypercapnia in obesity hypoventilation syndrome: A randomised crossover study. In: Thorax. 2014 ; Vol. 69, No. 4. pp. 346-353.
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title = "Moderate concentrations of supplemental oxygen worsen hypercapnia in obesity hypoventilation syndrome: A randomised crossover study",
abstract = "Introduction In people with obesity hypoventilation syndrome (OHS), breathing 100{\%} oxygen increases carbon dioxide (PCO2), but its effect on pH is unknown. This study investigated the effects of moderate concentrations of supplemental oxygen on PCO2, pH, minute ventilation (VE) and physiological dead space to tidal volume ratio (VD/VT) among people with stable untreated OHS, with comparison to healthy controls. Methods In a double-blind randomised crossover study, participants breathed oxygen concentrations (FiO2) 0.28 and 0.50, each for 20 min, separated by a 45 min washout period. Arterialised-venous PCO2 (PavCO2) and pH, VE and VD/VT were measured at baseline, then every 5 min. Data were analysed using general linear model analysis. Results 28 participants were recruited (14 OHS, 14 controls). Among OHS participants (mean±SD arterial PCO2 6.7±0.5 kPa; arterial oxygen 8.9±1.4 kPa) FiO2 0.28 and 0.50 maintained oxygen saturation 98-100{\%}. After 20 min of FiO2 0.28, PavCO 2 change (¿PavCO2) was 0.3±0.2 kPa (p=0.013), with minimal change in VE and rises in VD/VT of 1±5{\%} (p=0.012). F iO2 0.50 increased PavCO2 by 0.5±0.4 kPa (p=0.012), induced acidaemia and increased VD/VT by 3±3{\%} ( p=0.012). VE fell by 1.2±2.1 L/min within 5 min then recovered individually to varying degrees. A negative correlation between ¿VE and ¿PavCO2 (r=-0.60, p=0.024) suggested that ventilatory responses were the key determinant of PavCO2 rises. Among controls, FiO2 0.28 and 0.50 did not change PavCO2 or pH, but FiO2 0.50 significantly increased VE and VD/VT. Conclusion Commonly used oxygen concentrations caused hypoventilation, PavCO2 rises and acidaemia among people with stable OHS. This highlights the potential dangers of this common intervention in this group.",
keywords = "Adult, Blood Gas Analysis, Carbon Dioxide, Cross-Over Studies, Double-Blind Method, Female, Humans, Hydrogen-Ion Concentration, Hypercapnia, Male, Middle Aged, Obesity Hypoventilation Syndrome, Oxygen, Tidal Volume",
author = "Hollier, {Carly A.} and Harmer, {Alison R.} and Maxwell, {Lyndal J.} and Collette Menadue and Grant WILLSON and Gunnar Unger and Daniel Flunt and Black, {Deborah A.} and Piper, {Amanda J.}",
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doi = "10.1136/thoraxjnl-2013-204389",
language = "English",
volume = "69",
pages = "346--353",
journal = "Thorax",
issn = "0040-6376",
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Hollier, CA, Harmer, AR, Maxwell, LJ, Menadue, C, WILLSON, G, Unger, G, Flunt, D, Black, DA & Piper, AJ 2014, 'Moderate concentrations of supplemental oxygen worsen hypercapnia in obesity hypoventilation syndrome: A randomised crossover study', Thorax, vol. 69, no. 4, pp. 346-353. https://doi.org/10.1136/thoraxjnl-2013-204389

Moderate concentrations of supplemental oxygen worsen hypercapnia in obesity hypoventilation syndrome: A randomised crossover study. / Hollier, Carly A.; Harmer, Alison R.; Maxwell, Lyndal J.; Menadue, Collette; WILLSON, Grant; Unger, Gunnar; Flunt, Daniel; Black, Deborah A.; Piper, Amanda J.

In: Thorax, Vol. 69, No. 4, 2014, p. 346-353.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Moderate concentrations of supplemental oxygen worsen hypercapnia in obesity hypoventilation syndrome: A randomised crossover study

AU - Hollier, Carly A.

AU - Harmer, Alison R.

AU - Maxwell, Lyndal J.

AU - Menadue, Collette

AU - WILLSON, Grant

AU - Unger, Gunnar

AU - Flunt, Daniel

AU - Black, Deborah A.

AU - Piper, Amanda J.

PY - 2014

Y1 - 2014

N2 - Introduction In people with obesity hypoventilation syndrome (OHS), breathing 100% oxygen increases carbon dioxide (PCO2), but its effect on pH is unknown. This study investigated the effects of moderate concentrations of supplemental oxygen on PCO2, pH, minute ventilation (VE) and physiological dead space to tidal volume ratio (VD/VT) among people with stable untreated OHS, with comparison to healthy controls. Methods In a double-blind randomised crossover study, participants breathed oxygen concentrations (FiO2) 0.28 and 0.50, each for 20 min, separated by a 45 min washout period. Arterialised-venous PCO2 (PavCO2) and pH, VE and VD/VT were measured at baseline, then every 5 min. Data were analysed using general linear model analysis. Results 28 participants were recruited (14 OHS, 14 controls). Among OHS participants (mean±SD arterial PCO2 6.7±0.5 kPa; arterial oxygen 8.9±1.4 kPa) FiO2 0.28 and 0.50 maintained oxygen saturation 98-100%. After 20 min of FiO2 0.28, PavCO 2 change (¿PavCO2) was 0.3±0.2 kPa (p=0.013), with minimal change in VE and rises in VD/VT of 1±5% (p=0.012). F iO2 0.50 increased PavCO2 by 0.5±0.4 kPa (p=0.012), induced acidaemia and increased VD/VT by 3±3% ( p=0.012). VE fell by 1.2±2.1 L/min within 5 min then recovered individually to varying degrees. A negative correlation between ¿VE and ¿PavCO2 (r=-0.60, p=0.024) suggested that ventilatory responses were the key determinant of PavCO2 rises. Among controls, FiO2 0.28 and 0.50 did not change PavCO2 or pH, but FiO2 0.50 significantly increased VE and VD/VT. Conclusion Commonly used oxygen concentrations caused hypoventilation, PavCO2 rises and acidaemia among people with stable OHS. This highlights the potential dangers of this common intervention in this group.

AB - Introduction In people with obesity hypoventilation syndrome (OHS), breathing 100% oxygen increases carbon dioxide (PCO2), but its effect on pH is unknown. This study investigated the effects of moderate concentrations of supplemental oxygen on PCO2, pH, minute ventilation (VE) and physiological dead space to tidal volume ratio (VD/VT) among people with stable untreated OHS, with comparison to healthy controls. Methods In a double-blind randomised crossover study, participants breathed oxygen concentrations (FiO2) 0.28 and 0.50, each for 20 min, separated by a 45 min washout period. Arterialised-venous PCO2 (PavCO2) and pH, VE and VD/VT were measured at baseline, then every 5 min. Data were analysed using general linear model analysis. Results 28 participants were recruited (14 OHS, 14 controls). Among OHS participants (mean±SD arterial PCO2 6.7±0.5 kPa; arterial oxygen 8.9±1.4 kPa) FiO2 0.28 and 0.50 maintained oxygen saturation 98-100%. After 20 min of FiO2 0.28, PavCO 2 change (¿PavCO2) was 0.3±0.2 kPa (p=0.013), with minimal change in VE and rises in VD/VT of 1±5% (p=0.012). F iO2 0.50 increased PavCO2 by 0.5±0.4 kPa (p=0.012), induced acidaemia and increased VD/VT by 3±3% ( p=0.012). VE fell by 1.2±2.1 L/min within 5 min then recovered individually to varying degrees. A negative correlation between ¿VE and ¿PavCO2 (r=-0.60, p=0.024) suggested that ventilatory responses were the key determinant of PavCO2 rises. Among controls, FiO2 0.28 and 0.50 did not change PavCO2 or pH, but FiO2 0.50 significantly increased VE and VD/VT. Conclusion Commonly used oxygen concentrations caused hypoventilation, PavCO2 rises and acidaemia among people with stable OHS. This highlights the potential dangers of this common intervention in this group.

KW - Adult

KW - Blood Gas Analysis

KW - Carbon Dioxide

KW - Cross-Over Studies

KW - Double-Blind Method

KW - Female

KW - Humans

KW - Hydrogen-Ion Concentration

KW - Hypercapnia

KW - Male

KW - Middle Aged

KW - Obesity Hypoventilation Syndrome

KW - Oxygen

KW - Tidal Volume

U2 - 10.1136/thoraxjnl-2013-204389

DO - 10.1136/thoraxjnl-2013-204389

M3 - Article

VL - 69

SP - 346

EP - 353

JO - Thorax

JF - Thorax

SN - 0040-6376

IS - 4

ER -