Background: During the outbreak of coronavirus disease 2019 (COVID-19) many studies have investigated laboratory biomarkers in management and prognostication of COVID-19 patients, however to date, few have investigated arterial blood gas (ABG), acid-base and blood pressure (BP) patterns. The aim of the study is to assess the ABG and acid-base patterns, BP findings and their association with the outcomes of COVID-19 patients admitted to an intensive care unit (ICU). Methods: A single-centre retrospective, observational study in a dedicated COVID-19 ICU in Cape Town, South Africa. Admission ABG, serum electrolytes, renal function and BP readings performed on COVID-19 patients admitted between 26 March and 2 June 2020 were analysed and compared between survivors and non-survivors. Results: A total of 56 ICU patients had admission ABG performed at the time of ICU admission. An alkalaemia (pH > 7.45) was observed in 36 (64.3%) patients. A higher arterial pH [median 7.48 (IQR: 7.45-7.51 vs. 7.46 (IQR: 7.40-7.48), p=0.049] and partial pressure of oxygen in arterial blood [PaO2; median 7.9kPa (IQR 7.3- 9.6) vs. 6.5kPa (IQR: 5.2-7.3), p=<0.001] were significantly associated with survival. Survivors also tended to have a higher systolic BP [median: 144mmHg (IQR: 134- 152) vs. 139mmHg (IQR: 125-142), p=0.078] and higher arterial HCO3 [median: 28.0mmol/L (IQR: 25.7- 28.8) vs. 26.3mmol/L (IQR: 24.3-27.9); p=0.059). Conclusions: The majority of the study population admitted to ICU had an alkalaemia on ABG. A higher pH and lower PaO2 on ABG analysis were significantly associated with survival.