The wave of COVID research continues, much of it low-quality and hurriedly published. This is apparently the norm for academic publishing during a pandemic: fast, furious and haphazard.

However, two very significant reviews appeared in The Lancet this week that impact and inform anaesthetists and other critical care specialists.

Post-operative mortality, COVID & surgery

Early pandemic data suggested that COVID-19 patients having even minor elective surgery suffered worse post-operative outcomes, particularly high post-operative mortality. The COVIDSurg Collaborative has confirmed this after a multicenter trial across 24 countries.

Across the entire 1,128 patient cohort, 30-day mortality was a jaw-dropping 24%. Yes, 1 in 4 died within 30 days of surgery.

Pulmonary complications (pneumonia, ARDS or unexpected post-op ventilation) were very common (51%) and were associated with an even higher mortality (38%; and 83% of all deaths). Mortality was unsurprisingly associated with older age ≥ 70 years, male sex, ASA ≥ 3, emergency surgery, major surgery, and malignancy.

But even among low-risk groups, post-operative mortality was shockingly high: 30-49 year olds (6%), women (18%), ASA 1-2 patients (12%), and even those without comorbidities (7%). Being asymptomatic at admission did not have a significant protective effect (22% vs 27% mortality).

Elective surgery still carried a 19% mortality rate, and even for minor surgery mortality was 16%! Anaesthesia modality (local, regional or GA) did not have a significant impact.

Click through to read the summary or full-text, though the obvious take-away is that non-essential surgery should be avoided as much as is possible in those with confirmed or suspected COVID.

This will have huge implications for recommencement of elective surgery in many pandemic-hit countries. (Cook & Harrop-Griffiths explore this very topic in an NHS-context in their recent editorial.)

Physical distancing, face-masks & eye protection

On the back of another Lancet study the WHO has changed their advice on wearing face-masks. The WHO now recommends that the general public wear face-masks when unable to physically distance.

In this review and meta-analysis, the Canadian COVID-19 SURGE group (Systematic Urgent Review Group Effort) looked at the effect of three non-pharmacological interventions on coronavirus transmission:

  • Physical distancing
  • Face masks
  • Eye protection

They analysed 172 observational studies with over 25,000 patients in both community and healthcare settings, covering not just SARS-CoV-2, but also SARS and MERS.

Reassuringly they showed that physical distancing > 1 meter was associated with lower transmission risk (risk difference 95% CI -11.5 to -7.5%) and also increasing protection as distance extended beyond 2 meters.

Face-masks were also associated with reduced transmission (risk difference 95% CI -14.3% to -15.9%, though with low certainty), as was eye protection (risk difference 95% CI -12.5% to -7.7%).

Interestingly N95 masks were even more strongly associated with risk reduction, as was mask use in a health-care setting vs non-health-care. Both N95 and multi-layer surgical masks were more protective than single-layer masks.

The take-home is that simple protective behavioural changes, namely physical distancing, face-mask use and eye protection ARE associated with a significant risk reduction of coronavirus transmission.

Quick takes...

Bonus speed-round: Boulware et al. reported in the NEJM on their RCT of hydroxychloroquine for COVID post-exposure prophylaxis. Bottom-line, HCQ probably gives no post-exposure benefit when taken within 4 days of COVID exposure.

And keeping everyone on their toes on the back of the Surgiphere COVID data scandal, two notable COVID retractions in both The Lancet and NEJM:

Take-home? Signal or noise, it's hard to say – but a sci-fi writer, an adult-content model and cryptocurrency are a unique mix in the medical data industry...

Relevant papers

  1. COVIDSurg Collaborative. Mortality and pulmonary complications in patients undergoing surgery with perioperative SARS-CoV-2 infection: an international cohort study. Lancet. 2020 May 29.
  2. Cook TM Harrop-Griffiths W. Kicking on while it's still kicking off - getting surgery and anaesthesia restarted after COVID-19. Anaesthesia. 2020 May 19.
  3. Chu DK, Akl EA, Duda S et al. Physical distancing, face masks, and eye protection to prevent person-to-person transmission of SARS-CoV-2 and COVID-19: a systematic review and meta-analysis. Lancet. 2020 Jun 1.
  4. Boulware DR, Pullen MF, Bangdiwala AS et al. A Randomized Trial of Hydroxychloroquine as Postexposure Prophylaxis for Covid-19. N. Engl. J. Med. 2020 Jun 3.