Correlating arterial blood gas, acid-base and blood pressure abnormalities with outcomes in COVID-19 intensive care patients

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, acid-base and blood pressure patterns. The aim of the study is to assess the arterial blood gas and acid-base patterns, blood pressure findings and their association with the outcomes of COVID-19 patients admitted to an intensive care unit.

METHODS

A single-centre retrospective, observational study in a dedicated COVID-19 intensive care unit in Cape Town, South Africa. Admission arterial blood gas, serum electrolytes, renal function and blood pressure 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 intensive care unit patients had admission arterial blood gas performed at the time of intensive care unit admission. An alkalaemia (pH > 7.45) was observed in 36 (64.3%) patients. A higher arterial pH (median 7.48 [interquartile range: 7.45-7.51] versus 7.46 [interquartile range: 7.40-7.48], P = 0.049) and partial pressure of oxygen in arterial blood (median 7.9 kPa [interquartile range: 7.3-9.6] versus 6.5 kPa [interquartile range: 5.2-7.3], P = <0.001) were significantly associated with survival. Survivors also tended to have a higher systolic blood pressure (median: 144 mmHg [interquartile range: 134-152] versus 139 mmHg [interquartile range: 125-142], P = 0.078) and higher arterial HCO₃ (median: 28.0 mmol/L [interquartile range: 25.7-28.8] versus 26.3 mmol/L [interquartile range: 24.3-27.9], P = 0.059).

CONCLUSIONS

The majority of the study population admitted to intensive care unit had an alkalaemia on arterial blood gas. A higher pH and lower partial pressure of oxygen in arterial blood on arterial blood gas analysis were significantly associated with survival.

Clinical evolution, management and outcomes of patients with COVID-19 admitted at Tygerberg Hospital, Cape Town, South Africa: a research protocol

INTRODUCTION

The outbreak of the SARS-CoV-2 virus causing COVID-19, declared a global pandemic by the WHO, is a novel infection with a high rate of morbidity and mortality. In South Africa, 55 421 cases have been confirmed as of 10 June 2020, with most cases in the Western Cape Province. Coronavirus leaves us in a position of uncertainty regarding the best clinical approach to successfully manage the expected high number of severely ill patients with COVID-19. This presents a unique opportunity to gather data to inform best practices in clinical approach and public health interventions to control COVID-19 locally. Furthermore, this pandemic challenges our resolve due to the high burden of HIV and tuberculosis (TB) in our country as data are scarce. This study endeavours to determine the clinical presentation, severity and prognosis of patients with COVID-19 admitted to our hospital.

METHODS AND ANALYSIS

The study will use multiple approaches taking into account the evolving nature of the COVID-19 pandemic. Prospective observational design to describe specific patterns of risk predictors of poor outcomes among patients with severe COVID-19 admitted to Tygerberg Hospital. Data will be collected from medical records of patients with severe COVID-19 admitted at Tygerberg Hospital. Using the Cox proportional hazards model, we will investigate the association between the survival time of patients with COVID-19 in relation to one or more of the predictor variables including HIV and TB.

ETHICS AND DISSEMINATION

The research team obtained ethical approval from the Health Research Ethics Committee of the Faculty of Medicine and Health Sciences, Stellenbosch University and Research Committee of the Tygerberg Hospital. All procedures for the ethical conduct of scientific investigation will be adhered to by the research team. The findings will be disseminated in clinical seminars, scientific forums and conferences targeting clinical care providers and policy-makers.

A prospective study on the outcome of human immunodeficiency virus-infected patients requiring mechanical ventilation in a high-burden setting

BACKGROUND

There is a paucity of data on the mortality of patients admitted to the intensive care unit (ICU), despite the fact that human immunodeficiency virus (HIV)-related diseases represent a significant burden to health care resources particularly in sub-Saharan Africa.

AIM

To describe the outcome and prognostic factors of HIV-infected patients requiring mechanical ventilation in an ICU.

DESIGN

Prospective observational study.

METHODS

All 54 patients (34.8 ± 10.4 years, 38 females) admitted with confirmed HIV from October 2012 until May 2013 were enrolled. Disease severity was graded according to APACHEII score. Admission diagnoses, clinical features and laboratory investigations, complications and outcomes were recorded.

RESULTS

The mean length of ICU stay was 11.0 days (range: 1-49 days), and 33 patients survived (ICU mortality: 38.9%). The in-hospital mortality at 30 days was 48.1%. ICU mortality was associated with an AIDS-defining diagnosis (OR = 7.97, P = 0.003). Non-survivors had higher APACHEII scores (25.8 vs. 18.6, P = 0.001) and lower mean admission CD4 counts (102.5 vs. 225.2, P = 0.014). Multiple logistical regression analysis confirmed the independent predictive value of WHO stage 4 disease (P = 0.008), lower mean CD4 count on admission (P = 0.057) and higher APACHEII score (P = 0.010) on ICU mortality, and WHO stage 4 (P = 0.007) and higher APACHE II score (P = 0.003) on 30-day mortality.

CONCLUSIONS

The ICU mortality of mechanically ventilated HIV-positive patients was high. WHO stage 4 disease and a higher APACHEII score were predictive of both ICU and 30-day mortality, whereas a low CD4 count on admission was associated with ICU mortality.

The diagnosis of pleural effusions

Pleural effusions arise from a variety of systemic, inflammatory, infectious and malignant conditions. Their precise etiological diagnosis depends on a combination of medical history, physical examination, imaging tests and pertinent pleural fluid analyses; including specific biomarkers (e.g., natriuretic peptides for heart failure, adenosine deaminase for tuberculosis, or mesothelin for mesothelioma). Invasive procedures, such as pleuroscopic biopsies, may be required for persistently symptomatic effusions which remain undiagnosed after the analysis of one or more pleural fluid samples. However, whenever parietal pleural nodularity or thickening exist, image-guided biopsies should first be attempted. This review addresses the current diagnostic approach to pleural effusions secondary to heart failure, pneumonia, cancer, tuberculosis and other less frequent conditions.

Risk factors for recurrence of haemoptysis following bronchial artery embolisation for life-threatening haemoptysis

SETTING

Life-threatening haemoptysis is a frequent and often fatal complication in areas with a high prevalence of tuberculosis (TB). Bronchial artery embolisation remains the standard initial treatment. Subsequent curative measures, such as surgical resection of the focus of haemorrhage, are generally recommended to prevent recurrence, but risk-based selection criteria have not been established.

OBJECTIVES

To identify risk factors for the recurrence of haemoptysis following embolisation.

DESIGN

Baseline characteristics were obtained from consecutive patients with life-threatening haemoptysis who were successfully embolised and followed up for at least 12 months.

RESULTS

Recurrence of haemoptysis was observed in 47% and was associated with increased mortality compared to patients without recurrence (31% vs. 10%, P = 0.021). Patients with recurrence experienced residual mild haemoptysis beyond the first week after embolisation (odds ratio [OR] 7.2), received blood transfusions (OR 5.3) or presented with an aspergilloma (OR 5.1). Conversely, the presence of active TB amenable to treatment (OR 0.3) protected patients from these events. Radiographic or angiographic appearance did not predict recurrence.

CONCLUSIONS

Recurrence of haemoptysis following embolisation for life-threatening haemoptysis is common and is associated with high mortality. The results of this study can contribute to the risk assessment of these patients and guide decisions regarding the urgency of definitive therapy.