Abstract
Objective: To assess the incidence and impact of metabolic acidosis in Indigenous and non-Indigenous patients
Design: Retrospective study.
Setting: Adult intensive care units (ICUs) from Australia and New Zealand.
Participants: Patients aged 16 years or older admitted to an Australian or New Zealand ICU in one of 195 contributing ICUs between January 2019 and December 2020 who had metabolic acidosis, defined as pH < 7.30, base excess (BE) < −4 mEq/L and PaCO2 ≤ 45 mmHg.
Main outcome measures: The primary outcome was the prevalence of metabolic acidosis. Secondary outcomes included ICU length of stay, hospital length of stay, receipt of renal replacement therapy (RRT), major adverse kidney events at 30 days (MAKE30), and hospital mortality.
Results: Overall, 248 563 patients underwent analysis, with 11 537 (4.6%) in the Indigenous group and 237 026 (95.4%) in the non-Indigenous group. The prevalence of metabolic acidosis was higher in Indigenous patients (9.3% v 6.1%; P < 0.001). Indigenous patients with metabolic acidosis received RRT more often (28.2% v 22.0%; P < 0.001), but hospital mortality was similar between the groups (25.8% in Indigenous v 25.8% in non-Indigenous; P = 0.971).
Conclusions: Critically ill Indigenous ICU patients are more likely to have a metabolic acidosis in the first 24 hours of their ICU admission, and more often received RRT during their ICU admission compared with non-Indigenous patients. However, hospital mortality was similar between the groups.
Globally, Indigenous people have higher rates of ill-health and dramatically shorter life expectancy than other groups living in the same countries.1 The Aboriginal and Torres Strait Islander and the Mãori people are recognised as the original inhabitants of Australia and Aotearoa New Zealand respectively. For these Indigenous peoples, the international findings of poorer health and lower life expectancy continue to be true.
Indigenous people comprise 3.3% of the Australian population and their lives differ in many important ways from the non-Indigenous population,2 including access to health care delivered in an accessible manner.3, 4, 5, 6 Despite known access barriers to health care, Indigenous people are still over-represented in intensive care unit (ICU) admissions and, in particular, have disproportionately higher rates of ICU admission due to sepsis and trauma. Further, admissions are more likely to be emergent, and the degree of physiological derangement at admission is greater, often with limited pre-morbid information despite membership of a high risk group.7,8 After adjustment for illness severity on ICU admission there is no difference in mortality between Indigenous and non-Indigenous people.7
Mãori people comprise around 16% of the New Zealand population and have worse health outcomes than Pãkehã people, with such inequities reflecting differences in health state, housing, education, employment, and social and economic deprivation.9 There are also differences in access to health care and in the quality of health care delivery for Mãori compared with non-Mãori people.9 Like Indigenous people, Mãori people are less likely to be admitted to the ICU after elective surgery and proportionately more likely to be admitted to the ICU as an emergency.10 Sepsis and trauma are also common reasons for ICU admission for Mãori people, and unlike Indigenous people, Mãori people admitted to the ICU have higher mortality rates than their Pãkehã counterparts.10
Decompensated metabolic acidosis is a major acid–base derangement in critically ill patients and may impair cardiac contractility, which may contribute to reduced oxygen delivery to tissues and induce insulin resistance. It is associated with increased mortality.11, 12, 13 The incidence and prevalence of decompensated metabolic acidosis, and its consequences, in these cohorts of patients admitted to the ICU in Australia and New Zealand is unknown. However, as sepsis and trauma are common causes of metabolic acidosis in the ICU, metabolic acidosis may be a particular problem among both Indigenous Australians and Mãori New Zealanders (hereafter both respectfully referred to as Indigenous). We hypothesised that a greater proportion of Indigenous patients would present with a decompensated metabolic acidosis than non-Indigenous patients but that mortality outcomes would be equivalent.
The Australian and New Zealand Intensive Care Society (ANZICS) Adult Patient Database (APD) was used to identify all patients aged 16 years or older admitted to an Australian or New Zealand ICU in one of 195 contributing ICUs between January 2019 and December 2020 who had a decompensated metabolic acidosis, defined as a pH < 7.30, a base excess < −4 mEq/L and an arterial partial pressure of carbon dioxide (PaCO2) ≤ 45 mmHg, as previously described.13 De-identified data were extracted by an independent investigator following the best practices described in the ANZICS-APD manual.
The primary outcome was the prevalence of decompensated metabolic acidosis in Indigenous compared with non-Indigenous patients using the definition for Indigenous specified in the ANZICS-APD data dictionary.6 Secondary outcomes included:
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ICU length of stay;
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hospital length of stay;
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receipt of renal replacement therapy;
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major adverse kidney events at 30 days (MAKE30, defined as death or receipt of renal replacement therapy within 30 days); and
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hospital mortality among patients with decompensated metabolic acidosis.
The study was approved by the Alfred Health Human Research Ethics Committee (424/21).
Continuous variables were reported as median and interquartile range (IQR) and compared with the Kruskal–Wallis test. Categorical variables are reported as number and percentage and compared with Fisher exact test. Due to the large sample size included, the significance level was set at 0.01 and hypothesis testing was performed only for outcomes. All analyses were performed using R v.4.0.2.
Overall, 248 563 patients underwent analysis, with 11 537 patients (4.6%) in the Indigenous group (7723 [3.1%] Indigenous and 3814 [1.5%] Mãori) and 237 026 (95.4%) in the non-Indigenous group (Figure 1, A). The prevalence of decompensated metabolic acidosis was higher in Indigenous patients (9.3% v 6.1% [P < 0.001]; 9.4% in Indigenous v 9.2% in Mãori v 6.1% in non-Indigenous [P < 0.001]) (Figure 1, B). This was still higher in Indigenous patients even after the exclusion of patients with chronic kidney disease at baseline (8.8% v 5.9% [P < 0.001]; 8.8% in Indigenous v 8.8% in Mãori v 5.9% in non-Indigenous [P < 0.001]).
Figure 1.
Prevalence of Indigenous patients, decompensated metabolic acidosis, and use of renal replacement therapy (RRT) in Indigenous and non-Indigenous patients
A. Proportion of Indigenous and Māori among all critically ill patients admitted in the study period. The denominator used was the number of patients admitted to intensive care units (ICUs) in Australia (for Indigenous patients) or in New Zealand (for Māori patients). B. Proportion of patients with decompensated metabolic acidosis among all critically ill patients admitted in the study period. The denominator used was the number of patients admitted to ICUs in the study period. C. Proportion of patients receiving RRT among critically ill patients with decompensated metabolic acidosis. The denominator used was the number of patients with decompensated metabolic acidosis.
At baseline, Indigenous and Mãori patients with decompensated metabolic acidosis were similar. They were younger, had higher Acute Physiology and Chronic Health Evaluation (APACHE) II scores, more often had cardiac arrest preceding ICU admission, received mechanical ventilation at day 1, and received inotropes or vasopressors (Table 1). Indigenous patients with decompensated metabolic acidosis received renal replacement therapy more often (28.2% v 22.0% [P < 0.001]; 28.2% in Indigenous v 29.0% Mãori v 22.0% in non-Indigenous people [P < 0.001]) (Table 1 and Figure 1, C). After the exclusion of patients with chronic kidney disease at baseline, 23.2% of Indigenous compared with 20.5% of non-Indigenous patients (P = 0.069) received renal replacement therapy (21.2% in Indigenous v 27.7% Mãori v 20.5% in non-Indigenous; P = 0.024). Pairwise comparison according to each group is shown in Table 1. Hospital mortality was similar between the groups (24.2% in Indigenous v 29.4% Mãori v 25.8% in non-Indigenous patients; P = 0.181).
Table 1.
Baseline characteristics and clinical outcomes of patients with metabolic acidosis
| Overall | Indigenous | New Zealand Māori | Non–Indigenous | P | |
|---|---|---|---|---|---|
| Total number of patients | 15 458 | 726 | 350 | 14 382 | |
| Age, years, median (IQR) | 65 (51–75) | 51 (38–63) | 55 (37–66) | 66 (52–76) | < 0.001 |
| Sex, male | 8529 (55.2%) | 374 (51.5%) | 189 (54.0%) | 7966 (55.4%) | 0.106 |
| APACHE III | 76 (56–99) | 78 (58–101) | 81 (59–104) | 75 (56–99) | 0.014 |
| ANZROD | 10.2 (1.9–43.2) | 11.6 (2.3–41.0) | 14.9 (2.7–49.1) | 10.0 (1.9–43.2) | 0.081 |
| Elective surgery | 3175 (20.8%) | 63 (8.7%) | 35 (10.0%) | 3077 (21.6%) | < 0.001 |
| ICU source of admission | < 0.001 | ||||
| Operating room | 5960 (38.6%) | 162 (22.3%) | 110 (31.4%) | 5688 (39.6%) | |
| Emergency department | 6075 (39.3%) | 394 (54.3%) | 173 (49.4%) | 5508 (38.3%) | |
| Ward | 2114 (13.7%) | 81 (11.2%) | 43 (12.3%) | 1990 (13.8%) | |
| Other ICU, same hospital | 13 (0.1%) | 0 (0.0%) | 0 (0.0%) | 13 (0.1%) | |
| Other hospital | 983 (6.4%) | 64 (8.8%) | 16 (4.6%) | 903 (6.3%) | |
| Other hospital ICU | 297 (1.9%) | 20 (2.8%) | 8 (2.3%) | 269 (1.9%) | |
| Direct ICU admission from home | 15 (0.1%) | 5 (0.7%) | 0 (0.0%) | 10 (0.1%) | |
| Cardiac arrest within 24 hours | 1616 (10.6%) | 81 (11.2%) | 59 (17.0%) | 1476 (10.4%) | 0.001 |
| Mechanical ventilation on day 1 | 8968 (60.7%) | 458 (65.7%) | 178 (59.9%) | 8332 (60.4%) | 0.019 |
| Comorbidity | |||||
| Diabetes | 4545 (36.9%) | 328 (52.0%) | 93 (38.8%) | 4124 (36.0%) | < 0.001 |
| Chronic respiratory failure | 816 (5.3%) | 47 (6.5%) | 26 (7.4%) | 743 (5.2%) | 0.058 |
| Chronic cardiovascular disease | 1332 (8.6%) | 80 (11.0%) | 38 (10.9%) | 1214 (8.4%) | 0.018 |
| Cirrhosis | 407 (2.6%) | 34 (4.7%) | 3 (0.9%) | 370 (2.6%) | < 0.001 |
| Chronic kidney disease | 1036 (6.7%) | 116 (16.0%) | 34 (9.7%) | 886 (6.2%) | < 0.001 |
| Organ support during ICU stay | |||||
| Inotropes and/or vasopressors | 9657 (70.4%) | 485 (73.4%) | 216 (77.4%) | 8956 (70.1%) | 0.006 |
| Mechanical ventilation | 9204 (64.7%) | 437 (65.6%) | 194 (67.8%) | 8573 (64.6%) | 0.472 |
| Laboratory tests on day 1, median (IQR) | |||||
| pH | 7.25 (7.20–7.28) | 7.24 (7.19–7.28) | 7.24 (7.16–7.27) | 7.26 (7.20–7.28) | < 0.001 |
| Base excess, mEq/L | –11.2 (–15.2 to −8.5) | –12.1–16.5 to −9.1) | –12.1 (–17.4 to −8.8) | –11.1 (–15.0 to −8.4) | < 0.001 |
| PaO2:FiO2 ratio, mmHg | 260 (164–368) | 242 (154–367) | 276 (180–380) | 260 (164–367) | 0.026 |
| PaCO2, mmHg | 39 (33–42) | 37 (31–42) | 38 (32–42) | 39 (34–42) | < 0.001 |
| Lactate, mmol/L | 3.0 (1.6–6.4) | 3.0 (1.5–6.4) | 4.3 (2.0–8.9) | 3.0 (1.6–6.3) | < 0.001 |
| Highest creatinine, μmol/L | 143 (89–248) | 165 (91–359) | 170 (100–357) | 141 (89–242) | < 0.001 |
| Vital signs on day 1 | |||||
| Lowest mean arterial pressure, mmHg | 62 (56–68) | 63 (56–68) | 61 (54–67) | 62 (56–68) | 0.066 |
| Highest heart rate, beats/min | 106 (90–123) | 110 (96–125) | 110 (96–130) | 106 (90–123) | < 0.001 |
| Urine output, mL | 1315 (622–2130) | 1330 (475–2287) | 1500 (474–2595) | 1312 (630–2112) | 0.223 |
| Clinical outcomes | |||||
| ICU length of stay, days | 2.7 (1.3–5.5) | 3.3 (1.8–6.9) | 1.9 (1.1–3.9) | 2.7 (1.3–5.5) | < 0.001*, †, ‡ |
| Hospital length of stay, days | 9.2 (4.2–18.0) | 9.5 (4.1–18.2) | 6.7 (2.8–14.3) | 9.3 (4.3–18.0) | < 0.001*, †, ‡ |
| Receipt of RRT | 2949 (22.4%) | 184 (28.2%) | 79 (29.0%) | 2686 (22.0%) | < 0.001†, ‡ |
| MAKE30 | 4952 (36.0%) | 249 (36.8%) | 135 (45.3%) | 4568 (35.8%) | 0.003‡ |
| Hospital mortality | 3978 (25.8%) | 175 (24.2%) | 103 (29.4%) | 3700 (25.8%) | 0.181 |
ANZROD = Australian and New Zealand Risk of Death; APACHE = Acute Physiology and Chronic Health Evaluation; Fio2 = fraction of inspired oxygen; ICU = intensive care unit; IQR = interquartile range; MAKE30 = major kidney adverse events on day 30; Paco2 = arterial partial pressure of carbon dioxide; Pao2 = arterial partial pressure of oxygen; RRT = renal replacement therapy.
P < 0.01 for the Indigenous versus Mãori comparison.
P < 0.01 for the Indigenous versus non-Indigenous.
P < 0.01 for Mãori versus non-Indigenous.
We have shown that critically ill Indigenous and Mãori patients are more likely to have a decompensated metabolic acidosis in the first 24 hours of their ICU admission and that, when compared with non-Indigenous patients, they more often received renal replacement therapy during their ICU admission. However, hospital mortality was similar between Indigenous and non-Indigenous patients. Our findings imply the need to conduct trials to effectively treat decompensated metabolic acidosis which disproportionately affect Indigenous Australians and Mãori New Zealanders.
Competing interests
All authors declare that they do not have any potential conflict of interest in relation to this manuscript.
Acknowledgements
We acknowledge all the sites that contributed data to the present study: Albury Wodonga Health ICU, Alfred Hospital ICU, Alice Springs Hospital ICU, Angliss Hospital ICU, Armadale Health Service ICU, Ashford Community Hospital ICU, Auckland City Hospital CV ICU, Auckland City Hospital DCCM, Austin Hospital ICU, Ballarat Health Services ICU, Bankstown-Lidcombe Hospital ICU, Bathurst Base Hospital ICU, Bendigo Health Care Group ICU, Blacktown Hospital ICU, Box Hill Hospital ICU, Brisbane Private Hospital ICU, Buderim Private Hospital ICU, Bunbury Regional Hospital ICU, Bundaberg Base Hospital ICU, Caboolture Hospital ICU, Cabrini Hospital ICU, Cairns Hospital ICU, Calvary Adelaide Hospital ICU, Calvary Bruce Private Hospital HDU, Calvary Hospital (Canberra) ICU, Calvary Hospital (Lenah Valley) ICU, Calvary John James Hospital ICU, Calvary Mater Newcastle ICU, Calvary North Adelaide Hospital ICU, Campbelltown Hospital ICU, Canberra Hospital ICU, Casey Hospital ICU, Central Gippsland Health Service (Sale) ICU, Christchurch Hospital ICU, Coffs Harbour Health Campus ICU, Concord Hospital (Sydney) ICU, Dandenong Hospital ICU, Dubbo Base Hospital ICU, Dunedin Hospital ICU, Epworth Eastern Private Hospital ICU, Epworth Freemasons Hospital ICU, Epworth Geelong ICU, Epworth Hospital (Richmond) ICU, Fairfield Hospital ICU, Fiona Stanley Hospital ICU, Flinders Medical Centre ICU, Flinders Private Hospital ICU, Footscray Hospital ICU, Frankston Hospital ICU, Gold Coast Private Hospital ICU, Gold Coast University Hospital ICU, Gosford Hospital ICU, Gosford Private Hospital ICU, Goulburn Base Hospital ICU, Goulburn Valley Health ICU, Grafton Base Hospital ICU, Greenslopes Private Hospital ICU, Griffith Base Hospital ICU, Hawkes Bay Hospital ICU, Hervey Bay Hospital ICU, Hollywood Private Hospital ICU, Holmesglen Private Hospital ICU, Hornsby Ku-ring-gai Hospital ICU, Hurstville Private Hospital ICU, Hutt Hospital ICU, Ipswich Hospital ICU, John Fawkner Hospital ICU, John Flynn Private Hospital ICU, John Hunter Hospital ICU, Joondalup Health Campus ICU, Kareena Private Hospital ICU, Knox Private Hospital ICU, Latrobe Regional Hospital ICU, Launceston General Hospital ICU, Lingard Private Hospital ICU, Lismore Base Hospital ICU, Liverpool Hospital ICU, Logan Hospital ICU, Lyell McEwin Hospital ICU, Mackay Base Hospital ICU, Macquarie University Private Hospital ICU, Maitland Hospital ICU, Maitland Private Hospital ICU , Manning Rural Referral Hospital ICU, Maroondah Hospital ICU, Mater Adults Hospital (Brisbane) ICU, Mater Health Services North Queensland ICU, Mater Private Hospital (Brisbane) ICU, Mater Private Hospital (Sydney) ICU, Melbourne Private Hospital ICU, Middlemore Hospital ICU, Mildura Base Public Hospital ICU, Monash Medical Centre-Clayton Campus ICU, Mount Hospital ICU, Mount Isa Hospital ICU, Mulgrave Private Hospital ICU, National Capital Private Hospital ICU, Nelson Hospital ICU, Nepean Hospital ICU, Nepean Private Hospital ICU, Newcastle Private Hospital ICU, Noosa Hospital ICU, North Shore Hospital ICU, North Shore Private Hospital ICU, North West Regional Hospital (Burnie) ICU, Northeast Health Wangaratta ICU, Northern Beaches Hospital ICU, Norwest Private Hospital ICU, Orange Base Hospital ICU, Peninsula Private Hospital ICU, Pindara Private Hospital ICU, Port Macquarie Base Hospital ICU, Prince of Wales Hospital (Sydney) ICU, Prince of Wales Private Hospital (Sydney) ICU, Princess Alexandra Hospital ICU, Queen Elizabeth II Jubilee Hospital ICU, Redcliffe Hospital ICU, Robina Hospital ICU, Rockhampton Hospital ICU, Rockingham General Hospital ICU, Rotorua Hospital ICU, Royal Adelaide Hospital ICU, Royal Brisbane and Women’s Hospital ICU, Royal Darwin Hospital ICU, Royal Hobart Hospital ICU, Royal Melbourne Hospital ICU, Royal North Shore Hospital ICU, Royal Perth Hospital ICU, Royal Prince Alfred Hospital ICU, Ryde Hospital and Community Health Services ICU, Shoalhaven Hospital ICU, Sir Charles Gairdner Hospital ICU, South West Healthcare (Warrnambool) ICU, Southern Cross Hospital (Wellington) ICU, St Andrew’s Hospital (Adelaide) ICU, St Andrew’s Hospital Toowoomba ICU, St Andrew’s Private Hospital (Ipswich) ICU, St Andrew’s War Memorial Hospital ICU, St George Hospital (Sydney) ICU, St George Private Hospital (Sydney) ICU, St John of God (Berwick) ICU, St John Of God Health Care (Subiaco) ICU, St John Of God Hospital (Ballarat) ICU, St John of God Hospital (Bendigo) ICU, St John Of God Hospital (Geelong) ICU, St John Of God Hospital (Murdoch) ICU, St John of God Midland Public & Private ICU, St Vincent’s Private Hospital Northside ICU, St Vincent’s Hospital (Melbourne) ICU, St Vincent’s Hospital (Sydney) ICU, St Vincent’s Hospital (Toowoomba) ICU, St Vincent’s Private Hospital (Sydney) ICU, St Vincent’s Private Hospital Fitzroy ICU, Sunnybank Hospital ICU, Sunshine Coast University Hospital ICU, Sunshine Coast University Private Hospital ICU, Sunshine Hospital ICU, Sutherland Hospital & Community Health Services ICU, Sydney Adventist Hospital ICU, Sydney Southwest Private Hospital ICU, Tamworth Base Hospital ICU, Taranaki Health ICU, Tauranga Hospital ICU, The Bays Hospital ICU, The Chris O’Brien Lifehouse ICU, The Memorial Hospital (Adelaide) ICU, The Northern Hospital ICU, The Prince Charles Hospital ICU, The Queen Elizabeth (Adelaide) ICU, The Wesley Hospital ICU, Timaru Hospital ICU, Toowoomba Hospital ICU, Townsville University Hospital ICU, Tweed Heads District Hospital ICU, University Hospital Geelong ICU, Wagga Wagga Base Hospital & District Health ICU, Waikato Hospital ICU, Warringal Private Hospital ICU, Wellington Hospital ICU, Werribee Mercy Hospital ICU, Western District Health Service (Hamilton) ICU, Western Hospital (SA) ICU, Westmead Hospital ICU, Westmead Private Hospital ICU, Whakatane Hospital ICU, Whangarei Area Hospital - Northland Health Ltd ICU, Wimmera Health Care Group (Horsham) ICU, Wollongong Hospital ICU, Wollongong Private Hospital ICU, Women’s and Children’s Hospital PICU, Wyong Hospital ICU.
References
- 1.United Nations State of the world’s Indigenous peoples — Indigenous peoples’ access to health services. UN. 2013 https://www.un.org/esa/socdev/unpfii/documents/2016/Docs-updates/SOWIP_Health.pdf (viewed Sept 2021) [Google Scholar]
- 2.Australian Bureau of Statistics . Commonwealth of Australia; Canberra: 2018. Estimates of Aboriginal and Torres Strait Islander Australians: summary commentary [Cat. No. 3238.0.55.001]https://www.abs.gov.au/ausstats/abs@.nsf/mf/3238.0.55.001 (viewed Sept 2021) [Google Scholar]
- 3.Australian Institute of Health and Welfare . AIHW; Canberra: 2015. The health and welfare of Australia’s Aboriginal and Torres Strait Islander peoples: 2015 [Cat. No. IHW 42]https://www.aihw.gov.au/reports/indigenous-health-welfare/indigenous-health-welfare-2015/contents/table-of-contents (viewed Sept 2021) [Google Scholar]
- 4.Lamb S., Huo S. Mitchell Institute; Melbourne: 2017. Counting the costs of lost opportunity in Australian education. [Mitchell Institute Report No. 02/2017]https://www.vu.edu.au/sites/default/files/counting-the-costs-of-lost-opportunity-in-Aus-education-mitchell-institute.pdf (viewed Sept 2021) [Google Scholar]
- 5.Australian Bureau of Statistics . Commonwealth of Australia; Canberra: 2017. 2016 Census shows growing Aboriginal and Torres Strait Islander population [media release]https://www.abs.gov.au/ausstats/abs@.nsf/MediaRealesesByCatalogue/02D50FAA9987D6B7CA25814800087E03 (viewed Sept 2021) [Google Scholar]
- 6.Australian and New Zealand Intensive Care Society Centre for Outcomes and Resource Evaluation . ANZCIS CORE; Melbourne: 2017. APD data dictionary: ANZICS CORE — adult patient database; version 5.12.https://www.anzics.com.au/adult-patient-databaseapd (viewed Sept 2021) [Google Scholar]
- 7.Secombe P., Brown A., McAnulty G., Pilcher D. Aboriginal and Torres Strait Islander patients requiring critical care: characteristics, resource use, and outcomes. Crit Care Resusc. 2019;21:200–211. [PubMed] [Google Scholar]
- 8.Hughes J.T., Majoni S.W., Barzi F., et al. Incident haemodialysis and outcomes in the Top End of Australia. Aust Health Rev. 2020;44:234–240. doi: 10.1071/AH18230. [DOI] [PubMed] [Google Scholar]
- 9.Reid P., Cormack D., Paine S.J. Colonial histories, racism and health — the experience of Māori and Indigenous peoples. Public Health. 2019;172:119–124. doi: 10.1016/j.puhe.2019.03.027. [DOI] [PubMed] [Google Scholar]
- 10.Slim M.A.M., Lala H.M., Barnes N., Martynoga R.A. Māori health outcomes in an intensive care unit in Aotearoa New Zealand. Anaesth Intensive Care. 2021 doi: 10.1177/0310057X21989715. [DOI] [PubMed] [Google Scholar]
- 11.Jung B., Rimmele T., Le Goff C., et al. Severe metabolic or mixed acidemia on intensive care unit admission: incidence, prognosis and administration of buffer therapy. A prospective, multiple-center study. Crit Care. 2011;15:R238. doi: 10.1186/cc10487. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 12.Noritomi D.T., Soriano F.G., Kellum J.A., et al. Metabolic acidosis in patients with severe sepsis and septic shock: a longitudinal quantitative study. Crit Care Med. 2009;37:2733–2739. doi: 10.1097/ccm.0b013e3181a59165. [DOI] [PubMed] [Google Scholar]
- 13.Mochizuki K., Fujii T., Paul E., et al. Early metabolic acidosis in critically ill patients: a binational multicentre study. Crit Care Resusc. 2021;23:67–75. doi: 10.51893/2021.1.OA6. [DOI] [PMC free article] [PubMed] [Google Scholar]