Evidence check
A rapid review outlining the available evidence on a discrete topic or question. Evidence includes grey and peer review literature. View all Evidence Checks by date of publication.
Archive Cardiopulmonary resuscitation (CPR)
Added: 8 Apr 2020
Updated: 25 Sep 2020
What is the evidence that cardiopulmonary resuscitation is aerosol generating?
What is the current advice for CPR in patients with suspected or confirmed COVID-19?
What is the current advice for CPR in patients with suspected or confirmed COVID-19?
- There are case reports of transmission of different infectious diseases as a result of cardiopulmonary resuscitation (CPR) - guidance from the Clinical Excellence Commission is for the use of resuscitation devices, such as masks to reduce risk
- CPR has been described as a potential aerosol generating procedure in multiple publications, however a systematic review saw non-significant results for increased risk of transmission for chest compressions
- Resuscitation Council UK, American Heart Association, Department of Health, Australian College for Emergency Medicine, Australian and New Zealand Committee on Rescuitation and the International liaison committee on resuscitation recommend that full aerosol generating procedure PPE be worn during CPR with known or suspected COVID-19
- Chest compressions, assisted ventilation, and advanced airway manoeuvres are all considered potentially aerosol-generating procedures requiring appropriate PPE, whereas defibrillation can be performed wearing droplet precautions, if the patient’s mouth and nose are covered
- Resuscitation Council UK recommends if the rhythm is shockable to use a defibrillator prior to chest compressions. Compression-only resuscitation is recommended by multiple sources.
Archive COVID-19 infection and transmission in domestic animals
Added: 15 Sep 2020
Updated: 16 Sep 2020
Can domestic animals become infected with COVID-19, and is there evidence of transmission of COVID-19?
- There have been isolated incidents of domestic animals testing positive for the COVID-19 virus. (1-7) Generally, in these cases, the pet owners have been COVID-19 positive.
- The infected domestic animals reported in the literature are mainly dogs and cats, and studies reported either natural (1, 2) or experimental infection with the SARS-CoV-2.(6, 8, 9)
- Infected pets may show clinical symptoms (2, 3), or they may remain asymptomatic.(4, 10, 11) Most of the pets that were infected with COVID-19 had mild symptoms and fully recovered.
Archive Triage tools for ICU admission during COVID-19
Added: 13 Apr 2020
Updated: 16 Sep 2020
What triage tools are available to guide decisions about admission to ICU during COVID-19?
- There is considerable guidance around general principles for triaging patients to intensive care units during COVID-19. Key themes include, have decisions made by at least three physicians, multidisciplinary, shared and ethical decision making, documentation and transparency, reserving ICU admission for patients requiring ICU-specific interventions and not using age, on its own, as criteria.
- For COVID-19 specifically guidance is available including
- NICE rapid guidance including a critical care referral algorithm (which were updated on 31st March), and the Swiss Academy of Medical Sciences released guidelines for ICU triage. Criteria from opinion sources and other organisations were also identified
- Triage criteria is generally based on clinical criteria and probability of survival, with a recently published triage tool also including criteria on likely duration of stay
- Some of the guidance specifies that criteria apply to all patients potentially in need of ICU admission not only to COVID-19 infected patients
Archive Resuming elective surgery – volume-outcome relationships in surgery
Added: 28 Aug 2020
What is the evidence regarding a volume-outcome relationship for surgical interventions?
- For some surgical procedures, there is evidence of a volume-outcome relationship – a correlation between lower number of cases and poorer outcomes.
- Volume-outcome relationships have been evaluated at both a surgeon and hospital level. For procedures with a shorter length of stay and specific intraoperative processes and skills, the volume of procedures performed by the surgeon are more likely to influence outcomes, while for procedures with longer lengths of stay, the volume of procedures performed at the hospital is more likely to be important.
- Definitions of what constitutes a ‘low volume’ varies across studies, countries and conditions. Reporting of definitions of volumes is often inadequate and not consistent across studies.
- Outcomes reported include mortality, postoperative complications, length of stay, cost of hospital stay, and readmissions and reoperations/revisions.
- The quality of studies and strength of association between volumes and outcomes varies.
- Conditions where a volume-outcome relationship has been reported in systematic reviews include: pancreaticoduodenectomy, colon, rectal and colorectal cancer, bariatric surgery, breast cancer, abdominal aortic aneurysm, spinal surgery, cystectomy, oesophageal cancer, stomach cancer, head and neck cancer, lung cancer, radical prostatectomy, gynaecology surgery, carotid endarterectomy, paediatric heart surgery, AIDS, hysterectomy, thyroidectomy, transcatheter aortic valve implantation, nephrectomy, hernia, acute aortic syndrome, revascularisation of the lower limbs, hip and shoulder arthroplasty.
- Conditions where volume-outcome relationship has not been clearly established include liver resections, Norwood procedure, adrenocortical carcinoma and thoracic aortic aneurysms
- There is mixed evidence across reviews regarding percutaneous coronary intervention, hernia, trauma and injury, and coronary artery bypass grafting.
Archive Medium and long-term health sequelae of COVID-19
Added: 26 Aug 2020
What are the medium- and long-term health sequelae of COVID-19 infection among survivors?
- Symptoms commonly reported among recovered COVID-19 patients two to eight weeks after the onset of symptoms (or a positive COVID-19 test) include: fatigue, shortness of breath, muscle or joint pain, chest pain, cough, and insomnia and/or sleep disorders.(1-6)
- A study of 202 confirmed COVID-19 patients with mild symptoms, found altered sense of smell or taste occurred in 18.6% of patients, feelings of being tired in 13.1%, problems breathing in 10.4% and muscle or joint pains in 7.7%.(2) Another study of 143 patients reported fatigue in 53.1%, dyspnea in 43.4%, joint pain in 27.3%, and chest pain 21.7% of patients.(1)
- A study conducted among discharged intensive care unit (ICU) and ward COVID-19 patients found that post-traumatic stress disorder, anxiety and/or depression, voice change, laryngeal sensitivity, new continence problems and dysphagia were commonly reported among recovered patients.(5)
Archive Surgical masks and oxygen therapy
Added: 19 Aug 2020
What is the evidence for wearing a surgical mask at the same time as an oxygen mask?
- In vitro and clinical studies have demonstrated that placing a surgical mask on patients significantly reduces dispersion distance and levels of virus-infected bio-aerosol 20cm away from patients while coughing.
- To mitigate the risk of spread of disease, a nasal cannula can be placed and covered with a surgical mask to limit the potential for environmental contamination.
- Evidence on the percentage of supplemental oxygen that is delivered to the patient when wearing both a surgical mask and oxygen mask in the context of COVID-19 is lacking. A short report tested breathing air wearing a surgical mask on the face, second, breathing 6 l.min−1 oxygen via a Hudson mask placed over the top of a surgical mask and third, breathing 6 l.min−1 oxygen via a Hudson mask placed underneath a surgical mask, where the FIO2 measured was 0.20, 0.50 and 0.54, respectively.
- Evidence on whether an oxygen mask can be worn over the top of a surgical mask, or underneath it includes: o A joint international consensus document recommends keeping a simple surgical face mask on patient, over nasal prongs and under any type of oxygen face mask. A short report calls for a surgical mask to be placed over the patient’s nose and mouth immediately following extubation, and for a Hudson mask to be placed on top due to the negligible difference in FIO2 when the Hudson mask is placed over a surgical mask. Chinese consensus guidelines also describe that the surgical or N95 mask is applied under the oxygen mask. While some consensus guidelines recommend placement of a surgical mask over patients being treated with high flow therapies.
Archive Vascular dysfunction and COVID-19
Added: 5 Aug 2020
What are the symptoms and incidence for vascular events in patients with COVID-19?
- Thrombotic vasculopathy - A systematic review of 11 studies including 1,765 COVID-19 positive patients reported the occurrence of venous thromboembolism (VTE) in approximately 20% of patients.
- Cerebrovascular manifestations - A systematic review has reported occurrence of stroke in 3.5% of patients based on a pooled analysis of five studies including 973 patients. Many patients with cerebrovascular complications have cerebrovascular risk factors, such as hypertension, diabetes mellitus, hyperlipidaemia, high BMI, smoking or previous stroke history.
- Systemic vasculitis - An association between COVID-19 infection and novel paediatric vasculitis, named later as multisystem inflammatory syndrome in children (MIS-C) has not yet been established, due to inconsistent testing of COVID-19, although it seems plausible, given the temporal association. In adults, the spectrum of complications following COVID-19 is broader than in children and includes autoimmune diseases, but their incidence is low. Case reports describe a wide range of clinical presentations of COVID-19 related to systemic vasculitis including cutaneous manifestations, and possible vascular involvement in remote tissues.
- Neurovascular involvement - In a retrospective study of 214 patients with COVID-19, neurologic symptoms were seen in 36% of patients and were more common in patients with severe infection. Apart from cerebrovascular disease and impaired consciousness, most neurologic manifestations occurred early in the illness. Involvement of vascular endothelium in hyperinflammatory pro-thrombotic state has been proposed as a possible mechanism for neurologic manifestations in patients with severe COVID-19.
Archive Face masks and COVID-19 transmission in the community
Added: 19 Jun 2020
Updated: 20 Jul 2020
What is the evidence that face masks help prevent the spread of COVID-19 in the community?
- Context – transmission There is direct evidence of contact and droplet transmission of COVID-19. Flow physics and experimental models suggest, but have not demonstrated, airborne transmission. Epidemiological data on infection rates and transmission patterns are difficult to reconcile with long-range aerosol-based transmission. Where symptomatic patients are cared for, no studies to date have found viable virus in air samples.
- Context – other jurisdictions Community mask use is either encouraged or mandatory in over 80 countries. Face coverings have been mandated in parts of Victoria. In countries with community transmission, the adoption of mandatory face mask use has been associated with decreasing infection rates. These decreases have not been directly attributed to face mask use, as a suite of measures is generally adopted.
- Face mask evidence – non-COVID-19 Multiple systematic reviews examine the effect of face masks in community settings on reducing influenza like illness. Results are conflicting, with some reporting a protective effect and others no significant reduction in influenza like illness transmission. Respiratory etiquette, hand hygiene, social distancing, and isolation of cases, have a much stronger evidence base than face masks. Face masks are considered to be an additional measure, but there are concerns that masks can give a false sense of protection and may result in decreased compliance with other infection prevention practices.
- Face mask evidence – COVID-19 There is very little evidence on use of face masks on public transport, however some reviews conclude masks may have a role in settings where social distancing is not feasible. Some experts counsel a precautionary approach despite a lack of clear evidence. Cloth masks have variable filtration depending on the fabric. A systematic review found no studies on mask use among COVID-19 negative people in community settings.
Rapid evidence checks are based on a simplified review method and may not be entirely exhaustive, but aim to provide a balanced assessment of what is already known about a specific problem or issue. This brief has not been peer-reviewed and should not be a substitute for individual clinical judgement, nor is it an endorsed position of NSW Health. Evidence checks are archived a year after the date of publication.