Inhaled anaesthetics and nitrous oxide: Complexities overlooked: things may not be what they seem

AuthorsHendrickx, J.
Peyton, P.
Carette, R.
De Wolf, A.
TypeJournal Article (Review)
JournalEuropean Journal of Anaesthesiology
PubMed ID27164016
Year of Publication2016
URLhttp://www.ncbi.nlm.nih.gov/pubmed/27164016
DOIhttp://dx.doi.org/10.1097/eja.0000000000000467
Download 2016_EJA_Peyton.pdf (791.8 KB)
AbstractThis review re-examines existing pharmacokinetic and pharmacodynamic concepts of inhaled anaesthetics. After showing where uptake is hidden in the classic FA/FI curve, it is argued that target-controlled delivery of inhaled agents warrants a different interpretation of the factors affecting this curve (cardiac output, ventilation and blood/gas partition coefficient). Blood/gas partition coefficients of modern agents may be less important clinically than generally assumed. The partial pressure cascade from delivered to inspired to end-expired is re-examined to better understand the effect of rebreathing during low-flow anaesthesia, including the possibility of developing a hypoxic inspired mixture despite existing machine standards. Inhaled agents are easy to administer because they are transferred according to partial pressure gradients. In addition, the narrow dose-response curves for the three end points of general anaesthesia (loss of response to verbal command, immobility and autonomic reflex control) allow the clinical use of MACawake, MAC and MACBAR to determine depth of anaesthesia. Opioids differentially affect these clinical effects of inhaled agents. The effect of ventilation-perfusion relationships on gas uptake is discussed, and it is shown how moving beyond Riley's useful but simplistic model allows us to better understand both the concept and the magnitude of the second gas effect of nitrous oxide. It is argued that nitrous oxide remains a clinically useful drug. We hope to bring old (but ignored) and new (but potentially overlooked) information into the educational and clinical arenas to stimulate discussion among clinicians and researchers. We should not let technology pass by our all too engrained older concepts.

http://www.ibas.org.au/what-we-do/publications/3872861


< More publications



SHiQ - COSAQSHIQ - COSAQ

Each year in Australia 260 people sustain a SCI, with over half losing full function in their arms and legs (quadriplegia). In addition to the primary disability, there is a very high rate of Obstructive...

Notch monitoring in sleepNOTCH MONITORING IN SLEEP

Sleep apnea is a condition where breathing is abnormal during sleep. There are two main forms of sleep apnea: obstructive and central. For obstructive sleep apnea, breathing is reduced because the airway...

IBAS Director Anna Burke unveiling of her portrait at Canberra's Parliament HouseIBAS DIRECTOR ANNA BURKE UNVEILING OF HER PORTRAIT AT CANBERRA'S PARLIAMENT HOUSE

Anna Burke had barely got into the swing of her speech at the unveiling of her portrait at Canberra's Parliament House when the ringing of bells caused half her audience to hurry away

Thunderstorm asthma expected to return in 2017THUNDERSTORM ASTHMA EXPECTED TO RETURN IN 2017

The Morning Show - Thunderstorm asthma expected to return in 2017. The Daily Edition - Thunderstorm Asthma is an unexpected killer. Better Health Channel - Thunderstorm asthma explained. Professor Christine McDonald

National study offers hope for breathlessnessNATIONAL STUDY OFFERS HOPE FOR BREATHLESSNESS

A national medication study is aiming to help thousands of Australians who struggle every day with shortness of breath

Helping Victorians breathe and sleep easy - A New Centre of Excellence in Respiratory and Sleep MedicineHELPING VICTORIANS BREATHE AND SLEEP EASY - A NEW CENTRE OF EXCELLENCE IN RESPIRATORY AND SLEEP MEDICINE

With your support we will build a life-changing Centre of Excellence in Respiratory and Sleep Medicine, improving quality of life and health outcomes for Victorians who struggle to breathe and sleep

Institute for Breathing and Sleep

Bowen Centre, Austin Hospital
145 Studley Road
Heidelberg, Victoria, 3084

(03) 9496 5390

Email Us

Donate