The optimal management of the patient with COVID-19 pneumonia: HFNC, NIV/CPAP or mechanical ventilation?

The recent pandemic has seen unprecedented demand for respiratory support of patients with COVID-19 pneumonia, stretching services and clinicians. Yet despite the global numbers of patients treated, guidance is not clear on the correct choice of modality or the timing of escalation of therapy for an individual patient. This narrative review assesses the available literature on the best use of different modalities of respiratory support for an individual patient, and discusses benefits and risks of each, coupled with practical advice to improve outcomes. On current data, in an ideal context, it appears that as disease severity worsens, conventional oxygen therapy is not sufficient alone. In more severe disease, i.e. PaO2/FiO2 ratios below approximately 200, helmet-CPAP (continuous positive airway pressure) (although not widely available) may be superior to high-flow nasal cannula (HFNC) therapy or facemask non-invasive ventilation (NIV)/CPAP, and that facemask NIV/CPAP may be superior to HFNC, but with noted important complications, including risk of pneumothoraces. In an ideal context, invasive mechanical ventilation should not be delayed where indicated and available. Vitally, the choice of respiratory support should not be prescriptive but contextualised to each setting, as supply and demand of resources vary markedly between institutions. Over time, institutions should develop clear policies to guide clinicians before demand exceeds supply, and should frequently review best practice as evidence matures.

Outcomes of patients with COVID-19 acute respiratory distress syndrome requiring invasive mechanical ventilation admitted to an intensive care unit in South Africa.

BACKGROUND: Up to 32% of patients with COVID-19 pneumonia may require intensive care unit (ICU) admission or mechanical ventilation. Data from low- and middle-income countries on COVID-19 acute respiratory distress syndrome (ARDS) are limited. Groote Schuur Hospital in Cape Town, South Africa, expanded its intensive care service to support patients with COVID-19 ARDS requiring invasive mechanical ventilation (IMV). OBJECTIVES: To report on patients' characteristics and outcomes from the first two pandemic waves. METHODS: All patients with COVID-19 ARDS admitted to the ICU for IMV were included in this prospective cohort study. Data were collected from 5 April 2020 to 5 April 2021. RESULTS: Over the 12-month study period, 461 patients were admitted to the designated COVID-19 ICU. Of these, 380 met the study criteria and 377 had confirmed hospital discharge outcomes. The median (range) age of patients was 51 (17 - 71) years, 50.5% were female, and the median (interquartile range (IQR)) body mass index was 32 (28 - 38) kg/m2. The median (IQR) arterial oxygen partial pressure to fractional inspired oxygen (P/F) ratio was 97 (71 - 128) after IMV was initiated. Comorbidities included diabetes (47.6%), hypertension (46.3%) and HIV infection (10.5%). Of the patients admitted, 30.8% survived to hospital discharge with a median (IQR) ICU length of stay of 19.5 (9 - 36) days. Predictors of mortality after adjusting for confounders were male sex (odds ratio (OR) 1.74), increasing age (OR 1.04) and higher Sequential Organ Failure Assessment (SOFA) score (OR 1.29). CONCLUSIONS: In a resource-limited environment, the provision of IMV support in the ICU achieved 30.8% hospital survival in patients with COVID-19 ARDS. The ability to predict survival remains difficult given this complex disease.

The organisational response of a hospital critical care service to the COVID-19 pandemic: The Groote Schuur Hospital experience.

Background: There are limited data about the coronavirus disease-19 (COVID-19)-related organisational responses and the challenges of expanding a critical care service in a resource-limited setting. Objectives: To describe the ICU organisational response to the pandemic and the main outcomes of the intensive care service of a large state teaching hospital in South Africa. Methods: Data were extracted from administrative records and a prospective patient database with ethical approval. An ICU expansion plan was developed, and resource constraints identified. A triage tool was distributed to referring wards and hospitals. Intensive care was reserved for patients who required invasive mechanical ventilation (IMV). The total number of ICU beds was increased from 25 to 54 at peak periods, with additional non-COVID ICU capacity required during the second wave. The availability of nursing staff was the main factor limiting expansion. A ward-based high flow nasal oxygen (HFNO) service reduced the need for ICU admission of patients who failed conventional oxygen therapy. A team was established to intubate and transfer patients requiring ICU admission but was only available for the first wave. Results: We admitted 461 COVID-19 patients to the ICU over a 13-month period from 5 April 2020 to 5 May 2021 spanning two waves of admissions. The median age was 50 years and duration of ICU stay was 9 days. More than a third of the patients (35%; n=161) survived to hospital discharge. Conclusion: Pre-planning, leadership, teamwork, flexibility and good communication were essential elements for an effective response. A shortage of nurses was the main constraint on ICU expansion. HFNO may have reduced the requirement for ICU admission, but patients intubated after failing HFNO had a poor prognosis. Contributions of the study: We describe the organisational requirements to successfully expand critical care facilities and strategies to reduce the need for invasive mechanical ventilation in COVID-19 pneumonia. We also present the intensive care outcomes of these patients in a resource-constrained environment.

The Critical Care Society of Southern Africa guidelines on the allocation of scarce critical care resources during the COVID-19 public health emergency in South Africa.

Letter by Gopalan et al. on article by Singh and Moodley (Singh JA, Moodley K. Critical care triaging in the shadow of COVID-19: Ethics considerations. S Afr Med J 2020;110(5):355-359. https://doi.org/10.7196/SAMJ.2020.v110i5.14778); and response by Singh and Moodley.

Variation in timing of decisions to withdraw life-sustaining treatment in adult ICU patients from three centres in different geographies: Do clinical factors explain the difference?

Background: Decisions to withdraw life-sustaining treatment (WLST) are common in intensive care units (ICUs). Clinical and non-clinical factors are important, although the extent to which each plays a part is uncertain. Objectives: To determine whether the timing of decisions to WLST varies between ICUs in a single centre in three countries and whether differences in timing are explained by differences in clinical decision-making. Methods: The study involved a convenience sample of three adult ICUs - one in each of the UK, USA and South Africa (SA). Data were prospectively collected on patients whose life-sustaining treatment was withdrawn over three months. The timing of decisions was collected, as were patients' premorbid functional status and illness severity 24 hours prior to decision to WLST. Multivariate analysis was used to identify factors associated with decisions to WLST. Clinicians participated in interviews involving hypothetical case studies devoid of non-clinical factors. Results: Deaths following WLST accounted for 23% of all deaths during the study period at the USA site v. 37% (UK site) and 70% (SA site) (p<0.0010 across the three sites). Length of stay (LOS) prior to WLST decision varied between sites. Controlling for performance status, age, and illness severity, study site predicted LOS prior to decision (p<0.0010). In the hypothetical cases, LOS prior to WLST was higher for USA clinicians (p<0.017). Conclusion: There is variation in the proportion of ICU patients in whom WLST occurs and the timing of these decisions between sites; differences in clinical decision-making may explain the variation observed, although clinical and non-clinical factors are inextricably linked. Contributions of the study: This study has identified variation in the timing of decisions to withdraw life-sustaining treatment in adult ICUs in three centres in three different healthcare systems. Although differences in clinical decision-making likely explain some of the variation, non-clinical factors (relating to the society in which the clinicians live and work) may also play a part.

Resuscitation with hydroxyethyl starch improves renal function and lactate clearance in penetrating trauma in a randomized controlled study: the FIRST trial (Fluids in Resuscitation of Severe Trauma).

BACKGROUND: The role of fluids in trauma resuscitation is controversial. We compared resuscitation with 0.9% saline vs hydroxyethyl starch, HES 130/0.4, in severe trauma with respect to resuscitation, fluid volume, gastrointestinal recovery, renal function, and blood product requirements. METHODS: Randomized, controlled, double-blind study of severely injured patients requiring >3 litres of fluid resuscitation. Blunt and penetrating trauma were randomized separately. Patients were followed up for 30 days. RESULTS: A total of 115 patients were randomized; of which, 109 were studied. For patients with penetrating trauma (n=67), the mean (sd) fluid requirements were 5.1 (2.7) litres in the HES group and 7.4 (4.3) litres in the saline group (P<0.001). In blunt trauma (n=42), there was no difference in study fluid requirements, but the HES group required significantly more blood products [packed red blood cell volumes 2943 (1628) vs 1473 (1071) ml, P=0.005] and was more severely injured than the saline group (median injury severity score 29.5 vs 18; P=0.01). Haemodynamic data were similar, but, in the penetrating group, plasma lactate concentrations were lower over the first 4 h (P=0.029) and on day 1 with HES than with saline [2.1 (1.4) vs 3.2 (2.2) mmol litre⁻¹; P=0.017]. There was no difference between any groups in time to recovery of bowel function or mortality. In penetrating trauma, renal injury occurred more frequently in the saline group than the HES group (16% vs 0%; P=0.018). In penetrating trauma, maximum sequential organ function scores were lower with HES than with saline (median 2.4 vs 4.5, P=0.012). No differences were seen in safety measures in the blunt trauma patients. CONCLUSIONS: In penetrating trauma, HES provided significantly better lactate clearance and less renal injury than saline. No firm conclusions could be drawn for blunt trauma. STUDY REGISTRATION: ISRCTN 42061860.

Crystalloid preload versus rapid crystalloid administration after induction of spinal anaesthesia (coload) for elective caesarean section.

Current methods of crystalloid preload administration prior to spinal anaesthesia for elective caesarean section are relatively ineffective in preventing hypotension. This study examined the relevance of the timing of the fluid administered. Fifty women were randomly allocated to receive either 20 ml x kg(-1) of crystalloid solution during 20 minutes prior to induction of spinal anaesthesia (preload), or an equivalent volume by rapid infusion immediately after induction (coload). Significantly more patients in the coload group did not require vasopressor therapy pre-delivery (P=0.047). The coload group required a lower median dose (P=0.03) and a lower median number (P=0.04) of ephedrine doses for the treatment of maternal hypotension pre-delivery. There was no between-group difference in either the total cumulative dose, or in the total number of doses of ephedrine. Neonatal outcomes among the two groups were similar. Rapid crystalloid administration after, rather than over 20 minutes before the induction of spinal anaesthesia for elective caesarean section, may be advantageous in terms of managing maternal blood pressure prior to delivery.