B Biccard

Affiliations

Department of Anaesthesia and Perioperative Medicine, University of Cape Town and Groote Schuur Hospital, Cape Town, South Africa.

ORCID: https://orcid.org/0000-0001-5872-8369

Publications (20)

Variation in global uptake of the Surgical Safety Checklist.

The British journal of surgery

Avec: M Delisle , J C Pradarelli , N Panda , L Koritsanszky , Y Sonnay , S Lipsitz , R Pearse , E M Harrison , B Biccard , T G Weiser , A B Haynes , Auteur inconnu

Identifying knowledge needed to improve surgical care in Southern Africa using a theory of change approach.

BMJ global health

Avec: Danyca Shadé Breedt , Maria Lisa Odland , Balisi Bakanisi , Edward Clune , Moneimang Makgasa , John Tarpley , Margaret Tarpley , Akutu Munyika , Jacob Sheehama , Theresia Shivera , Bruce Biccard , Regan Boden , Sean Chetty , Liesl de Waard , Rowan Duys , Kristin Groeneveld , Susan Levine , Tamlyn Mac Quene , Salome Maswime , Megan Naidoo , Priyanka Naidu , Shrikant Peters , Ché L Reddy , Savannah Verhage , Godfrey Muguti , Shingai Nyaguse , Lucia D'Ambruoso , Kathryn Chu , Justine I Davies , Auteur inconnu

The development of a nurse-led preoperative anaesthesia screening tool by Delphi consensus.

South African medical journal = Suid-Afrikaanse tydskrif vir geneeskunde

Avec: M B Nejthardt , P Alexandris , S Bechan , M F A Bijli , S Chetty , J M Dippenaar , M Gibbs , M Johnson , H Kluyts , R Llewellyn , M Motiang , P Mogane , P Motshabi , B Mrara , F Roodt , U Singh , S Spijkerman , E Turton , J Van der Westhuizen , B Biccard

The lifetime risk of surgery in England: a nationwide observational cohort study.

British journal of anaesthesia

Avec: Sarah-Louise Watson , Alexander J Fowler , Priyanthi Dias , Bruce Biccard , Yize I Wan , Rupert M Pearse , Tom E F Abbott

Preoperative N-Terminal Pro-B-Type Natriuretic Peptide and Cardiovascular Events After Noncardiac Surgery: A Cohort Study.

Annals of internal medicine

Avec: Emmanuelle Duceppe , Ameen Patel , Matthew T V Chan , Otavio Berwanger , Gareth Ackland , Peter A Kavsak , Reitze Rodseth , Bruce Biccard , Clara K Chow , Flavia K Borges , Gordon Guyatt , Rupert Pearse , Daniel I Sessler , Diane Heels-Ansdell , Andrea Kurz , Chew Yin Wang , Wojciech Szczeklik , Sadeesh Srinathan , Amit X Garg , Shirley Pettit , Erin N Sloan , James L Januzzi , Matthew McQueen , Giovanna Lurati Buse , Nicholas L Mills , Lin Zhang , Robert Sapsford , Guillaume Paré , Michael Walsh , Richard Whitlock , Andre Lamy , Stephen Hill , Lehana Thabane , Salim Yusuf , P J Devereaux

External validation of the Revised Cardiac Risk Index and National Surgical Quality Improvement Program Myocardial Infarction and Cardiac Arrest calculator in noncardiac vascular surgery.

British journal of anaesthesia

Avec: J Fronczek , K Polok , P J Devereaux , J Górka , R A Archbold , B Biccard , E Duceppe , Y Le Manach , D I Sessler , M Duchińska , W Szczeklik

South African Paediatric Surgical Outcomes Study: a 14-day prospective, observational cohort study of paediatric surgical patients.

British journal of anaesthesia

Avec: A Torborg , L Cronje , J Thomas , H Meyer , A Bhettay , J Diedericks , C Cilliers , H Kluyts , B Mrara , M Kalipa , R Rodseth , B Biccard , Auteur inconnu

A scoping review of Enhanced Recovery After Surgery (ERAS), protocol implementation, and its impact on surgical outcomes and healthcare systems in Africa.

Perioperative medicine (London, England)

Avec: Fitsum Kifle , Peniel Kenna , Selam Daniel , Salome Maswime , Bruce Biccard

Consensus statement on measures to promote equitable authorship in the publication of research from international partnerships.

Anaesthesia

Avec: B Morton , A Vercueil , R Masekela , E Heinz , L Reimer , S Saleh , C Kalinga , M Seekles , B Biccard , J Chakaya , S Abimbola , A Obasi , N Oriyo

Understanding the performance of a pan-African intervention to reduce postoperative mortality: a mixed-methods process evaluation of the ASOS-2 trial.

British journal of anaesthesia

Avec: Nicola Vickery , Timothy Stephens , Leon du Toit , Dawid van Straaten , Rupert Pearse , Alexandra Torborg , Lucy Rolt , Mariechen Puchert , Graham Martin , Bruce Biccard , Auteur inconnu

Rationale and design of the PeriOperative ISchemic Evaluation-3 (POISE-3): a randomized controlled trial evaluating tranexamic acid and a strategy to minimize hypotension in noncardiac surgery.

Trials

Avec: Maura Marcucci , Thomas W Painter , David Conen , Kate Leslie , Vladimir V Lomivorotov , Daniel Sessler , Matthew T V Chan , Flavia K Borges , Maria J Martínez Zapata , C Y Wang , Denis Xavier , Sandra N Ofori , Giovanni Landoni , Sergey Efremov , Ydo V Kleinlugtenbelt , Wojciech Szczeklik , Denis Schmartz , Amit X Garg , Timothy G Short , Maria Wittmann , Christian S Meyhoff , Mohammed Amir , David Torres , Ameen Patel , Emmanuelle Duceppe , Kurtz Ruetzler , Joel L Parlow , Vikas Tandon , Michael K Wang , Edith Fleischmann , Carisi A Polanczyk , Raja Jayaram , Sergey V Astrakov , Mangala Rao , Tomas VanHelder , William K K Wu , Chao Chia Cheong , Sabry Ayad , Marat Abubakirov , Mikhail Kirov , Keyur Bhatt , Miriam de Nadal , Valery Likhvantsev , Pilar Paniagua Iglesisas , Hector J Aguado , Michael McGillion , Andre Lamy , Richard P Whitlock , Pavel Roshanov , David Stillo , Ingrid Copland , Jessica Vincent , Kumar Balasubramanian , Shrikant I Bangdiwala , Bruce Biccard , Andrea Kurz , Sadeesh Srinathan , Shirley Petit , John Eikelboom , Toby Richards , Peter L Gross , Pascal Alfonsi , Gordon Guyatt , Emily Belley-Cote , Jessica Spence , William McIntyre , Salim Yusuf , P J Devereaux

Point of care ultrasound findings in critically ill SARS-COV2 patients in an HIV endemic, resourced constrained setting.

Heliyon

Avec: Willem Marcelle Jagga , Bruce Biccard , Jenique Bailly , Ali Esmail , Katherine Antel , Jessica Opie

Mixed methods study protocol for combining stakeholder-led rapid evaluation with near real-time continuous registry data to facilitate evaluations of quality of care in intensive care units.

Wellcome open research

Avec: Auteur inconnu , Aasiyah Rashan , Abi Beane , Aniruddha Ghose , Arjen M Dondorp , Arthur Kwizera , Bharath Kumar Tirupakuzhi Vijayaraghavan , Bruce Biccard , Cassia Righy , C Louise Thwaites , Christopher Pell , Cornelius Sendagire , David Thomson , Dilanthi Gamage Done , Diptesh Aryal , Duncan Wagstaff , Farah Nadia , Giovanni Putoto , Hem Panaru , Ishara Udayanga , John Amuasi , Jorge Salluh , Krishna Gokhale , Krishnarajah Nirantharakumar , Luigi Pisani , Madiha Hashmi , Marcus Schultz , Maryam Shamal Ghalib , Mavuto Mukaka , Mohammed Basri Mat-Nor , Moses Siaw-Frimpong , Rajendra Surenthirakumaran , Rashan Haniffa , Ronnie P Kaddu , Snehal Pinto Pereira , Srinivas Murthy , Steve Harris , Suneetha Ramani Moonesinghe , Sutharshan Vengadasalam , Swagata Tripathy , Tiffany E Gooden , Timo Tolppa , Vrindha Pari , Wangari Waweru-Siika , Yen Lam Minh

Quality of recovery after total hip and knee arthroplasty in South Africa: a national prospective observational cohort study.

BMC musculoskeletal disorders

Avec: Ulla Plenge , Romy Parker , Shamiela Davids , Gareth L Davies , Zahnne Fullerton , Lindsay Gray , Penelope Groenewald , Refqah Isaacs , Ntambue Kauta , Frederik M Louw , Andile Mazibuko , David M North , Marc Nortje , Glen M Nunes , Neo Pebane , Chantal Rajah , John Roos , Paul Ryan , Winlecia V September , Heidi Shanahan , Ruth E Siebritz , Rian W Smit , Simon Sombili , Alexandra Torborg , Johan F van der Merwe , Nico van der Westhuizen , Bruce Biccard

Preoperative levels of natriuretic peptides and the incidence of postoperative atrial fibrillation after noncardiac surgery: a prospective cohort study.

CMAJ : Canadian Medical Association journal = journal de l'Association medicale canadienne

Avec: Wojciech Szczeklik , Yannick LeManach , Jakub Fronczek , Kamil Polok , David Conen , Finlay A McAlister , Sadeesh Srinathan , Pablo Alonso-Coello , Bruce Biccard , Emmanuelle Duceppe , Diane Heels-Ansdell , Jacek Górka , Shirley Pettit , Pavel S Roshanov , P J Devereaux

The association between preoperative anemia and postoperative morbidity in pediatric surgical patients: A secondary analysis of a prospective observational cohort study.

Paediatric anaesthesia

Avec: Heidi M Meyer , Alexandra Torborg , Larissa Cronje , Jennifer Thomas , Anisa Bhettay , Johan Diedericks , Celeste Cilliers , Hyla Kluyts , Busisiwe Mrara , Mandisa Kalipa , Bruce Biccard , Auteur inconnu

Normalized Subendocardial Myocardial Attenuation on Coronary Computed Tomography Angiography Predicts Postoperative Adverse Cardiovascular Events: Coronary CTA VISION Substudy.

Circulation. Cardiovascular imaging

Avec: Jeroen Walpot , Samia Massalha , Pranisha Jayasinghe , Madiha Sadaf , Owen Clarkin , Laura Godkin , Ashwin Sharma , Indeevari Ratnayake , Kara Godkin , Kateleen Jia , Alomgir Hossain , Andrew M Crean , Matthew Chan , Craig Butler , Vikas Tandon , Peter Nagele , Pamela K Woodard , Marko Mrkobrada , Wojciech Szczeklik , Yang Faridah Abdul Aziz , Bruce Biccard , P J Devereaux , Tej Sheth , Benjamin J W Chow

Systematic review and consensus definitions for the Standardized Endpoints in Perioperative Medicine (StEP) initiative: cardiovascular outcomes.

British journal of anaesthesia

Avec: W Scott Beattie , Manoj Lalu , Matthew Bocock , Simon Feng , Duminda N Wijeysundera , Peter Nagele , Lee A Fleisher , Andrea Kurz , Bruce Biccard , Kate Leslie , Simon Howell , Giovani Landoni , Hilary Grocott , Andre Lamy , Toby Richards , Paul Myles , Auteur inconnu , Auteur inconnu , Auteur inconnu , Auteur inconnu , Auteur inconnu , Auteur inconnu , Auteur inconnu , Auteur inconnu , Auteur inconnu , Auteur inconnu , Auteur inconnu , Auteur inconnu , Auteur inconnu , Auteur inconnu

The need for data describing the surgical population in Latin America.

British journal of anaesthesia

Avec: Luciana C Stefani , Ludhmila Hajjar , Bruce Biccard , Rupert M Pearse

Perioperative Transfusion Practices in Adults Having Noncardiac Surgery.

Transfusion medicine reviews

Avec: Michael Verret , Manoj Lalu , Daniel I Sessler , Flavia K Borges , Pavel S Roshanov , Alexis F Turgeon , Xavier Neveu , Tim Ramsay , Wojciech Szczeklik , Vikas Tandon , Ameen Patel , Bruce Biccard , P J Devereaux , Dean A Fergusson

Réseau de co-auteurs

None None 20 collaborations

Bruce Biccard 15 collaborations

P J Devereaux 6 collaborations

Wojciech Szczeklik 5 collaborations

Emmanuelle Duceppe 3 collaborations

Ameen Patel 3 collaborations

Flavia K Borges 3 collaborations

Andrea Kurz 3 collaborations

Sadeesh Srinathan 3 collaborations

Andre Lamy 3 collaborations

Alexandra Torborg 3 collaborations

Vikas Tandon 3 collaborations

Salome Maswime 2 collaborations

H Kluyts 2 collaborations

B Mrara 2 collaborations

Rupert M Pearse 2 collaborations

Matthew T V Chan 2 collaborations

Gordon Guyatt 2 collaborations

Rupert Pearse 2 collaborations

Daniel I Sessler 2 collaborations

Diane Heels-Ansdell 2 collaborations

Amit X Garg 2 collaborations

Shirley Pettit 2 collaborations

Salim Yusuf 2 collaborations

David Conen 2 collaborations

Kate Leslie 2 collaborations

Toby Richards 2 collaborations

Pavel S Roshanov 2 collaborations

Peter Nagele 2 collaborations

Manoj Lalu 2 collaborations

M Delisle 1 collaboration

J C Pradarelli 1 collaboration

N Panda 1 collaboration

L Koritsanszky 1 collaboration

Y Sonnay 1 collaboration

S Lipsitz 1 collaboration

R Pearse 1 collaboration

E M Harrison 1 collaboration

T G Weiser 1 collaboration

A B Haynes 1 collaboration

Danyca Shadé Breedt 1 collaboration

Maria Lisa Odland 1 collaboration

Balisi Bakanisi 1 collaboration

Edward Clune 1 collaboration

Moneimang Makgasa 1 collaboration

John Tarpley 1 collaboration

Margaret Tarpley 1 collaboration

Akutu Munyika 1 collaboration

Jacob Sheehama 1 collaboration

Theresia Shivera 1 collaboration

Regan Boden 1 collaboration

Sean Chetty 1 collaboration

Liesl de Waard 1 collaboration

Rowan Duys 1 collaboration

Kristin Groeneveld 1 collaboration

Susan Levine 1 collaboration

Tamlyn Mac Quene 1 collaboration

Megan Naidoo 1 collaboration

Priyanka Naidu 1 collaboration

Shrikant Peters 1 collaboration

Ché L Reddy 1 collaboration

Savannah Verhage 1 collaboration

Godfrey Muguti 1 collaboration

Shingai Nyaguse 1 collaboration

Lucia D'Ambruoso 1 collaboration

Kathryn Chu 1 collaboration

Justine I Davies 1 collaboration

M B Nejthardt 1 collaboration

P Alexandris 1 collaboration

S Bechan 1 collaboration

M F A Bijli 1 collaboration

S Chetty 1 collaboration

J M Dippenaar 1 collaboration

M Gibbs 1 collaboration

M Johnson 1 collaboration

R Llewellyn 1 collaboration

M Motiang 1 collaboration

P Mogane 1 collaboration

P Motshabi 1 collaboration

F Roodt 1 collaboration

U Singh 1 collaboration

S Spijkerman 1 collaboration

E Turton 1 collaboration

J Van der Westhuizen 1 collaboration

Sarah-Louise Watson 1 collaboration

Alexander J Fowler 1 collaboration

Priyanthi Dias 1 collaboration

Yize I Wan 1 collaboration

Tom E F Abbott 1 collaboration

Otavio Berwanger 1 collaboration

Gareth Ackland 1 collaboration

Peter A Kavsak 1 collaboration

Reitze Rodseth 1 collaboration

Clara K Chow 1 collaboration

Chew Yin Wang 1 collaboration

Erin N Sloan 1 collaboration

James L Januzzi 1 collaboration

Matthew McQueen 1 collaboration

Giovanna Lurati Buse 1 collaboration

Nicholas L Mills 1 collaboration

Lin Zhang 1 collaboration

Robert Sapsford 1 collaboration

Guillaume Paré 1 collaboration

Michael Walsh 1 collaboration

Richard Whitlock 1 collaboration

Stephen Hill 1 collaboration

Lehana Thabane 1 collaboration

J Fronczek 1 collaboration

K Polok 1 collaboration

J Górka 1 collaboration

R A Archbold 1 collaboration

E Duceppe 1 collaboration

Y Le Manach 1 collaboration

D I Sessler 1 collaboration

M Duchińska 1 collaboration

W Szczeklik 1 collaboration

A Torborg 1 collaboration

L Cronje 1 collaboration

J Thomas 1 collaboration

H Meyer 1 collaboration

A Bhettay 1 collaboration

J Diedericks 1 collaboration

C Cilliers 1 collaboration

M Kalipa 1 collaboration

R Rodseth 1 collaboration

Fitsum Kifle 1 collaboration

Peniel Kenna 1 collaboration

Selam Daniel 1 collaboration

B Morton 1 collaboration

A Vercueil 1 collaboration

R Masekela 1 collaboration

E Heinz 1 collaboration

L Reimer 1 collaboration

S Saleh 1 collaboration

C Kalinga 1 collaboration

M Seekles 1 collaboration

J Chakaya 1 collaboration

S Abimbola 1 collaboration

A Obasi 1 collaboration

N Oriyo 1 collaboration

Nicola Vickery 1 collaboration

Timothy Stephens 1 collaboration

Leon du Toit 1 collaboration

Dawid van Straaten 1 collaboration

Lucy Rolt 1 collaboration

Mariechen Puchert 1 collaboration

Graham Martin 1 collaboration

Maura Marcucci 1 collaboration

Thomas W Painter 1 collaboration

Vladimir V Lomivorotov 1 collaboration

Daniel Sessler 1 collaboration

Maria J Martínez Zapata 1 collaboration

C Y Wang 1 collaboration

Denis Xavier 1 collaboration

Sandra N Ofori 1 collaboration

Giovanni Landoni 1 collaboration

Sergey Efremov 1 collaboration

Ydo V Kleinlugtenbelt 1 collaboration

Denis Schmartz 1 collaboration

Timothy G Short 1 collaboration

Maria Wittmann 1 collaboration

Christian S Meyhoff 1 collaboration

Mohammed Amir 1 collaboration

David Torres 1 collaboration

Kurtz Ruetzler 1 collaboration

Joel L Parlow 1 collaboration

Michael K Wang 1 collaboration

Edith Fleischmann 1 collaboration

Carisi A Polanczyk 1 collaboration

Raja Jayaram 1 collaboration

Sergey V Astrakov 1 collaboration

Mangala Rao 1 collaboration

Tomas VanHelder 1 collaboration

William K K Wu 1 collaboration

Chao Chia Cheong 1 collaboration

Sabry Ayad 1 collaboration

Marat Abubakirov 1 collaboration

Mikhail Kirov 1 collaboration

Keyur Bhatt 1 collaboration

Miriam de Nadal 1 collaboration

Valery Likhvantsev 1 collaboration

Pilar Paniagua Iglesisas 1 collaboration

Hector J Aguado 1 collaboration

Michael McGillion 1 collaboration

Richard P Whitlock 1 collaboration

Pavel Roshanov 1 collaboration

David Stillo 1 collaboration

Ingrid Copland 1 collaboration

Jessica Vincent 1 collaboration

Kumar Balasubramanian 1 collaboration

Shrikant I Bangdiwala 1 collaboration

Shirley Petit 1 collaboration

John Eikelboom 1 collaboration

Peter L Gross 1 collaboration

Pascal Alfonsi 1 collaboration

Emily Belley-Cote 1 collaboration

Jessica Spence 1 collaboration

William McIntyre 1 collaboration

Willem Marcelle Jagga 1 collaboration

Jenique Bailly 1 collaboration

Ali Esmail 1 collaboration

Katherine Antel 1 collaboration

Jessica Opie 1 collaboration

Aasiyah Rashan 1 collaboration

Abi Beane 1 collaboration

Aniruddha Ghose 1 collaboration

Arjen M Dondorp 1 collaboration

Arthur Kwizera 1 collaboration

Bharath Kumar Tirupakuzhi Vijayaraghavan 1 collaboration

Cassia Righy 1 collaboration

C Louise Thwaites 1 collaboration

Christopher Pell 1 collaboration

Cornelius Sendagire 1 collaboration

David Thomson 1 collaboration

Dilanthi Gamage Done 1 collaboration

Diptesh Aryal 1 collaboration

Duncan Wagstaff 1 collaboration

Farah Nadia 1 collaboration

Giovanni Putoto 1 collaboration

Hem Panaru 1 collaboration

Ishara Udayanga 1 collaboration

John Amuasi 1 collaboration

Jorge Salluh 1 collaboration

Krishna Gokhale 1 collaboration

Krishnarajah Nirantharakumar 1 collaboration

Luigi Pisani 1 collaboration

Madiha Hashmi 1 collaboration

Marcus Schultz 1 collaboration

Maryam Shamal Ghalib 1 collaboration

Mavuto Mukaka 1 collaboration

Mohammed Basri Mat-Nor 1 collaboration

Moses Siaw-Frimpong 1 collaboration

Rajendra Surenthirakumaran 1 collaboration

Rashan Haniffa 1 collaboration

Ronnie P Kaddu 1 collaboration

Snehal Pinto Pereira 1 collaboration

Srinivas Murthy 1 collaboration

Steve Harris 1 collaboration

Suneetha Ramani Moonesinghe 1 collaboration

Sutharshan Vengadasalam 1 collaboration

Swagata Tripathy 1 collaboration

Tiffany E Gooden 1 collaboration

Timo Tolppa 1 collaboration

Vrindha Pari 1 collaboration

Wangari Waweru-Siika 1 collaboration

Yen Lam Minh 1 collaboration

Ulla Plenge 1 collaboration

Romy Parker 1 collaboration

Shamiela Davids 1 collaboration

Gareth L Davies 1 collaboration

Zahnne Fullerton 1 collaboration

Lindsay Gray 1 collaboration

Penelope Groenewald 1 collaboration

Refqah Isaacs 1 collaboration

Ntambue Kauta 1 collaboration

Frederik M Louw 1 collaboration

Andile Mazibuko 1 collaboration

David M North 1 collaboration

Marc Nortje 1 collaboration

Glen M Nunes 1 collaboration

Neo Pebane 1 collaboration

Chantal Rajah 1 collaboration

John Roos 1 collaboration

Paul Ryan 1 collaboration

Winlecia V September 1 collaboration

Heidi Shanahan 1 collaboration

Ruth E Siebritz 1 collaboration

Rian W Smit 1 collaboration

Simon Sombili 1 collaboration

Johan F van der Merwe 1 collaboration

Nico van der Westhuizen 1 collaboration

Yannick LeManach 1 collaboration

Jakub Fronczek 1 collaboration

Kamil Polok 1 collaboration

Finlay A McAlister 1 collaboration

Pablo Alonso-Coello 1 collaboration

Jacek Górka 1 collaboration

Heidi M Meyer 1 collaboration

Larissa Cronje 1 collaboration

Jennifer Thomas 1 collaboration

Anisa Bhettay 1 collaboration

Johan Diedericks 1 collaboration

Celeste Cilliers 1 collaboration

Hyla Kluyts 1 collaboration

Busisiwe Mrara 1 collaboration

Mandisa Kalipa 1 collaboration

Jeroen Walpot 1 collaboration

Samia Massalha 1 collaboration

Pranisha Jayasinghe 1 collaboration

Madiha Sadaf 1 collaboration

Owen Clarkin 1 collaboration

Laura Godkin 1 collaboration

Ashwin Sharma 1 collaboration

Indeevari Ratnayake 1 collaboration

Kara Godkin 1 collaboration

Kateleen Jia 1 collaboration

Alomgir Hossain 1 collaboration

Andrew M Crean 1 collaboration

Matthew Chan 1 collaboration

Craig Butler 1 collaboration

Pamela K Woodard 1 collaboration

Marko Mrkobrada 1 collaboration

Yang Faridah Abdul Aziz 1 collaboration

Tej Sheth 1 collaboration

Benjamin J W Chow 1 collaboration

W Scott Beattie 1 collaboration

Matthew Bocock 1 collaboration

Simon Feng 1 collaboration

Duminda N Wijeysundera 1 collaboration

Lee A Fleisher 1 collaboration

Simon Howell 1 collaboration

Giovani Landoni 1 collaboration

Hilary Grocott 1 collaboration

Paul Myles 1 collaboration

Luciana C Stefani 1 collaboration

Ludhmila Hajjar 1 collaboration

Michael Verret 1 collaboration

Alexis F Turgeon 1 collaboration

Xavier Neveu 1 collaboration

Tim Ramsay 1 collaboration

Dean A Fergusson 1 collaboration