Permissive hypercapnia

2002 ◽  
Vol 8 (2) ◽  
pp. 155-169 ◽  
Author(s):  
K HICKLING
Keyword(s):  
Permissive Hypercapnia

scholarly journals Carbon dioxide levels in neonates: what are safe parameters?

2021 ◽  
Author(s):  
Sie Kei Wong ◽  
M. Chim ◽  
J. Allen ◽  
A. Butler ◽  
J. Tyrrell ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Systematic Review ◽  
Side Effects ◽  
Preterm Infants ◽  
Periventricular Leukomalacia ◽  
List Type ◽  
Permissive Hypercapnia ◽  
Prisma Statement ◽  
Carbon Dioxide Levels ◽  
Online Software

Abstract There is no consensus on the optimal pCO2 levels in the newborn. We reviewed the effects of hypercapnia and hypocapnia and existing carbon dioxide thresholds in neonates. A systematic review was conducted in accordance with the PRISMA statement and MOOSE guidelines. Two hundred and ninety-nine studies were screened and 37 studies included. Covidence online software was employed to streamline relevant articles. Hypocapnia was associated with predominantly neurological side effects while hypercapnia was linked with neurological, respiratory and gastrointestinal outcomes and Retinpathy of prematurity (ROP). Permissive hypercapnia did not decrease periventricular leukomalacia (PVL), ROP, hydrocephalus or air leaks. As safe pCO2 ranges were not explicitly concluded in the studies chosen, it was indirectly extrapolated with reference to pCO2 levels that were found to increase the risk of neonatal disease. Although PaCO2 ranges were reported from 2.6 to 8.7 kPa (19.5–64.3 mmHg) in both term and preterm infants, there are little data on the safety of these ranges. For permissive hypercapnia, parameters described for bronchopulmonary dysplasia (BPD; PaCO2 6.0–7.3 kPa: 45.0–54.8 mmHg) and congenital diaphragmatic hernia (CDH; PaCO2 ≤ 8.7 kPa: ≤65.3 mmHg) were identified. Contradictory findings on the effectiveness of permissive hypercapnia highlight the need for further data on appropriate CO2 parameters and correlation with outcomes. Impact There is no consensus on the optimal pCO2 levels in the newborn. There is no consensus on the effectiveness of permissive hypercapnia in neonates. A safe range of pCO2 of 5–7 kPa was inferred following systematic review.

Permissive hypercapnia in extremely low birthweight infants (PHELBI): a randomised controlled multicentre trial

2015 ◽  
Vol 3 (7) ◽  
pp. 534-543 ◽  
Author(s):  
Ulrich H Thome ◽  
Orsolya Genzel-Boroviczeny ◽  
Bettina Bohnhorst ◽  
Manuel Schmid ◽  
Hans Fuchs ◽  
...  
Keyword(s):  
Low Birthweight ◽  
Multicentre Trial ◽  
Permissive Hypercapnia ◽  
Randomised Controlled ◽  
Extremely Low Birthweight

CAROTID BLOOD FLOW DURING PERMISSIVE HYPERCAPNIA IN AN OVINE MODEL

1993 ◽  
Vol 21 (Supplement) ◽  
pp. S190
Author(s):  
Thuan Nguyen ◽  
Charles Cox ◽  
Alex Tzounakis ◽  
Phillip Bush ◽  
Daniel Traber ◽  
...  
Keyword(s):  
Blood Flow ◽  
Permissive Hypercapnia ◽  
Ovine Model ◽  
Carotid Blood Flow

scholarly journals Permissive Hypercapnia and Risk for Brain Injury and Developmental Impairment

PEDIATRICS ◽  
2008 ◽  
Vol 122 (3) ◽  
pp. e583-e589 ◽  
Author(s):  
E. W. Hagen ◽  
M. Sadek-Badawi ◽  
D. P. Carlton ◽  
M. Palta
Keyword(s):  
Brain Injury ◽  
Permissive Hypercapnia ◽  
Developmental Impairment

Asthma and Cystic Fibrosis

2010 ◽  
Author(s):  
Robert Hilt ◽  
Alison Leary
Keyword(s):  
Carbon Dioxide ◽  
Cystic Fibrosis ◽  
Motor Development ◽  
Very Low Birth Weight ◽  
Permissive Hypercapnia ◽  
Low Birth Weight Infants ◽  
Respiratory Problems ◽  
Systemic Hypoxia ◽  
Carbon Dioxide Levels ◽  
Carbon Dioxide Co2

Asthma and cystic fibrosis (CF) are examples of childhood pulmonary illnesses with significant psychological impacts. These disorders have in common an induced difficulty with a primal drive, the drive to breathe. Acute impairment with the drive to breathe is highly anxiety provoking, and chronic impairment is life-altering. Pulmonary illnesses like asthma and CF can have direct impacts on brain functioning through systemic hypoxia (low blood oxygen [O2] level) or hypercapnia (high blood carbon dioxide [CO2] level) due to poor respiratory gas exchange. With chronic respiratory problems in children, hypoxia is the more clinically pertinent issue in that hypoxia seems to produce developmental impacts. Studies that have looked at the outcomes of pulmonary hypoxia have found associations with adverse effects even from oxygen levels that were just slightly below the normal range (Bass et al. 2004). A drop of only 4% O2 saturation from baseline is associated with attentiondeficit hyperactivity (ADHD)-like symptoms. Persistent oxygen saturation levels that are even lower than this have been associated with decreased IQ and delays in motor development (Bass et al. 2004). Negative neurobehavioral effects of the hypercapnia side of impaired respiratory status are less well documented. In fact, hypercapnia, besides triggering an increase in cerebral blood flow and driving a sense of air hunger particularly in people with trait anxiety, seems to have no lasting neurocognitive impact (Wan et al. 2008). Research on the use of intentional ‘‘permissive’’ hypercapnia when using mechanical ventilation assistance (allowing higher blood carbon dioxide levels to minimize barotrauma from the assist device) has shown no common neurocognitive complications from this strategy. There are even suggestions of some improved neurocognitive outcomes for neonates managed in this manner (Miller and Carlo 2007). These results are tempered by a higher reported frequency of intraventricular hemorrhage in hypercapnic very-low-birth-weight infants, and there is at least one case report of subarachnoid hemorrhage in a child ventilated with permissive hypercapnia for an asthma episode (Edmunds and Harrison 2003; Kaiser et al. 2006). The severe hypercapnia of complete respiratory failure goes hand in hand with hypoxia, so the effects of each in that potentially fatal scenario are difficult to separate.

Permissive Hypercapnia with and without Expiratory Washout in Patients with Severe Acute Respiratory Distress Syndrome 

1997 ◽  
Vol 87 (1) ◽  
pp. 6-17 ◽  
Author(s):  
Pierre Kalfon ◽  
G. S. Umamaheswara Rao ◽  
Lluis Gallart ◽  
Louis Puybasset ◽  
Pierre Coriat ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Acute Respiratory Distress Syndrome ◽  
Respiratory Distress Syndrome ◽  
Respiratory Distress ◽  
Injury Severity ◽  
Distress Syndrome ◽  
Permissive Hypercapnia ◽  
Positive End Expiratory Pressure ◽  
Ventilatory Strategy ◽  
Volume Curve

Background Permissive hypercapnia is a ventilatory strategy aimed at avoiding lung volutrauma in patients with severe acute respiratory distress syndrome (ARDS). Expiratory washout (EWO) is a modality of tracheal gas insufflation that enhances carbon dioxide removal during mechanical ventilation by reducing dead space. The goal of this prospective study was to determine the efficacy of EWO in reducing the partial pressure of carbon dioxide (PaCO2) in patients with severe ARDS treated using permissive hypercapnia. Methods Seven critically ill patients with severe ARDS (lung injury severity score, 3.1 +/- 0.3) and no contraindications for permissive hypercapnia were studied. On the first day, hemodynamic and respiratory parameters were measured and the extent of lung hyperdensities was assessed using computed tomography. A positive end-expiratory pressure equal to the opening pressure identified on the pressure-volume curve was applied. Tidal volume was reduced until a plateau airway pressure of 25 cm H2O was reached. On the second day, after implementation of permissive hypercapnia, EWO was instituted at a flow of 15 l/min administered during the entire expiratory phase into the trachea through the proximal channel of an endotracheal tube using a ventilator equipped with a special flow generator. Cardiorespiratory parameters were studied under three conditions: permissive hypercapnia, permissive hypercapnia with EWO, and permissive hypercapnia. Results During permissive hypercapnia, EWO decreased PaCO2 from 76 +/- 4 mmHg to 53 +/- 3 mmHg (-30%; P < 0.0001), increased pH from 7.20 +/- 0.03 to 7.34 +/- 0.04 (P < 0.0001), and increased PaO2 from 205 +/- 28 to 296 +/- 38 mmHg (P < 0.05). The reduction in PaCO2 was accompanied by an increase in end-inspiratory plateau pressure from 26 +/- 1 to 32 +/- 2 cm H2O (P = 0.001). Expiratory washout also decreased cardiac index from 4.6 +/- 0.4 to 3.7 +/- 0.3 l.min-1.m-2 (P < 0.01), mean pulmonary arterial pressure from 28 +/- 2 to 25 +/- 2 mmHg (P < 0.01), and true pulmonary shunt from 47 +/- 2 to 36 +/- 3% (P < 0.01). Conclusions Expiratory washout is an effective and easy-to-use ventilatory modality to reduce PaCO2 and increase pH during permissive hypercapnia. However, it significantly increases airway pressures and lung volume through expiratory flow limitation, reexposing some patients to a risk of lung volutrauma if the extrinsic positive end-expiratory pressure is not substantially reduced.

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