Abdelrahman, T.

Bailey, D. M.

Beamish, A.

Brown, C.

Chalklin, C.

Egan, R. J.

Eley, C.

Hopkins, Luke

Iannetelli, Angelo

James, Osian P.

Kokelaar, R.

Larsen, M.

Lewis, W. G.

Luton, O.

Mellor, K.

Powell, A.

Robinson, David B. T.

Stacey, Benjamin

Warren, N.

Williams, A.

Williams, I. M.

English

University of South Wales Research Explorer

 1 Personal Protective Equipment impairs pulmonary gas exchange causing systemic hypercapnia-hypoxaemia and cerebral hyperperfusion-induced cephalalgia  Osian P James1§, Benjamin Stacey2§, Luke Hopkins1, David BT Robinson1, Oliver Luton1, Ian M Williams3, Richard J Egan4,5, Damian M Bailey2§§, Wyn G Lewis1,3§§  1. Health Education and Improvement Wales’ School of Surgery, Tŷ Dysgu, Cefn Coed, Nantgarw, UK, CF15 7QQ. 2. Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Treforest, UK, CF37 4AT. 3. Department of Surgery, University Hospital of Wales, Cardiff, UK, CF14 4XW. 4. Department of Surgery, Morriston Hospital, Swansea, UK, SA6 6NL. 5. Swansea University, Singleton Park, Swansea, UK, SA2 8PP. §Authors contributed equally §§Joint senior and corresponding authors   On behalf of Welsh Surgical Research Initiative and Neurovascular Research Laboratory collaborators: Tarig Abdelrahman, Andrew Beamish, Christopher Brown, Christopher Chalklin, Catherine Eley, Angelo Iannetelli, Rory Kokelaar, Matthew Larsen, Katie Mellor, Arfon Powell, Neil Warren, Alex Williams.      2 Correspondence: Professor Damian Bailey, Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Treforest, CF37 4AT. E: damian.bailey@southwales.ac.uk.  Professor Wyn Lewis, Health Education and Improvement Wales’ School of Surgery, Tŷ Dysgu, Cefn Coed, Nantgarw, CF15 7QQ. E: LewisWG1@cardiff.ac.uk.  OPJ is supported by a Surgical Research Fellowship from the Royal College of Surgeons of England and Health Education and Improvement Wales. DMB is supported by a Royal Society Wolfson Research Fellowship (#WM170007), Royal Society International Exchanges Award (IES\R2\192137), Japan Society for the Promotion of Science Research Fellowship (#JSPS/OF317) and Higher Education Funding Council for Wales. No specific funding was received for this study.  Competing Interests: None Ethical Approval: Service Evaluation (Cardiff & Vale University Health Board) Research Letter  Word Count (ex. title page, references and table): 600       3 Existential catastrophes inflict change so vast and dislocating that it’s often hard to tell disaster from prospect. COVID-19 has forced radical shifts in working habits, in particular the recommendation that all clinical staff wear Personal Protective Equipment (PPE) in at risk environments1. Compounded by stressful tasks, staff have anecdotally reported respiratory distress, headaches, dehydration, and cognitive impairment, not reported previously without PPE2. To what extent PPE impacts integrated cardiopulmonary-cerebrovascular function has not been examined. The hypothesis tested was that PPE adversely influences pulmonary gas exchange, resulting in systemic hypercapnic-hypoxaemia and cerebral hyperperfusion-induced cephalalgia.  Eight male Higher Surgical Trainees (aged 33±2y) participated in a repeated-measures crossover study, completing two-hour laparoscopic simulation tasks, on two separate occasions: one conducted in standard surgical attire and the other in full PPE (FFP3 mask, visor, fluid-resistant apron and two pairs of latex gloves in addition to standard attire). Measurements were taken over 10-minutes, at zero and 120 minutes and included heart rate, mean arterial pressure (MAP), skin temperature, cephalalgia (visual analogue score) and body mass. Respiratory gases were sampled at the mouth through a sealed adaptation to each mask. Peak detection analysis was used to calculate respiratory rate and mean inspiratory concentrations of CO2 (FICO2) and O2 (FIO2) from inside the mask, with peripheral oxygen saturation (SpO2) measured via pulse oximetry. The proximal Middle Cerebral Artery (MCA) was insonated enabling measurement of MCA blood velocity (MCAV), thereby cerebral blood flow, and calculation of the Cerebrovascular  4 Conductance Index (CVCi), Cerebrovascular Resistance Index (CVRi) and Pulsatility Index (PI).  Baseline measurements without standard attire or full PPE indicated the FICO2 was 0.03% (±0.0%), FIO2 20.9% (±0.0%), and SpO2 97% (±0%). With immediate effect, full PPE increased FICO2 (p=0.025), and decreased both FIO2 (p=0.011) and SpO2 (p=0.001), when compared with wearing standard attire, regardless of simulation duration. MCA PI was higher wearing full PPE compared with standard attire (p=0.004). Body mass decreased by 0.3kg after two hours in both conditions (p=0.049), with skin temperature increased in full PPE (p=0.046) and after two hours of simulation (p=0.001) and exacerbated further following two hours in full PPE compared to two hours in standard attire (33.7±0.9° vs. 32.9±0.6°; p=0.025). Further details of results can be found in Table 1. No headaches were reported during simulation in standard surgical attire, but three participants reported fronto-temporal headache after two-hours wearing full PPE (p=0.055), which corresponded with increased MCAv (82±4 vs. 63±9 cm/s; p=0.008), CVCi (0.9±0.0 vs. 0.6±0.1 cm/s/mmHg; p=0.010) and CVRi (1.1±0.0 vs. 1.7±0.4 mmHg/cm/s; p=0.036) compared with cephalalgia-free participants.  The principal physiological findings were that full PPE adversely influenced pulmonary gas exchange, resulting in systemic hypercapnic-hypoxaemia and cerebral hyperperfusion-induced cephalalgia, supporting the hypothesis. Specifically, PPE was associated with an increase in FICO2 to almost 8%; a 260-fold increase on atmospheric CO2 (0.03%), with milder effects witnessed wearing standard operating attire (7%). These prevailing changes likely induced cerebral vasodilation (increased  5 MCAV) and increased cerebral pulsatility, which can lead to symptoms including dyspnoea, fatigue, sweating, dizziness, nausea, cognitive impairment, and headaches3-5. Although the effects of mild hypoxia are largely mitigated by intrinsic homeostatic mechanisms, the effects of hypercapnia are clearly significant, and introduce substantial risk to performance, health, patient safety, and quality of care. Moreover, these findings were observed in young, fit trainees, posing the question of what findings might emerge in older surgeons with comorbidity, or anyone operating beyond the two-hour limit utilised in this study.  Urgent protective countermeasures should be designed to prevent risk to healthcare staff and patients alike. Future research must explore the relationship between the hypercapnia observed and specific metrics of manual dexterity, cognition, and cerebral perfusion in exposed surgeons.              6 References 1. Welsh Surgical Research Initiative (WSRI) Collaborative. Surgery during the COVID‐19 pandemic: operating room suggestions from an international Delphi process. BJS. 2020;107:1450-1458. DOI: 10.1002/bjs.11747. 2. Benítez CY, Gűemes A, Aranda J et al. Impact of Personal Protective Equipment on Surgical Performance During the COVID-19 Pandemic. World J Surg. 2020;44:2842-2847. DOI: 10.1007/s00268-020-05648-2. 3. Chapman K, Dragan KE. Hypercarbia. In: StatPearls [online]. Treasure Island (FL, USA). 2020. Available at: https://www.ncbi.nlm.nih.gov/books/NBK559154/ [Accessed 26/10/2020]. 4. Kung S, Shen Y, Chang E et al. Hypercapnia impaired cognitive and memory functions in obese patients with obstructive sleep apnoea. Sci Rep. 2018;8(175510). DOI: 10.1038/s41598-018-35797-3. 5. Johnson AT. Respirator masks protect health but impact performance: a review. J Biol Eng. 2016;10:4. DOI: 10.1186/s13036-016-0025-4.   Tables (Supplemental file as landscape format)  Table 1. Integrated cardiopulmonary-cerebrovascular responses following simulated surgery as a function of participant attire. Data are means (± SD). FI = Fraction Inspired, MAP = Mean Arterial Pressure, MCAV = Middle Cerebral Artery blood flow Velocity, PI = Pulsatility Index, CVCi = Cerebrovascular Conductance Index, CVRi = Cerebrovascular Resistance Index. 

Personal protective equipment impairs pulmonary gas exchange causing systemic hypercapnia–hypoxaemia and cerebral hyperperfusion-induced cephalalgia

https://pure.southwales.ac.uk/files/5537471/PPE_letter_BJS_4_02_2021.pdf

Personal protective equipment impairs pulmonary gas exchange causing systemic hypercapnia–hypoxaemia and cerebral hyperperfusion-induced cephalalgia

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