Hypoxemia is the most common cause for hospitalization in COVID-19 patients. Acute hypoxemic respiratory failure or acute respiratory distress syndrome (ARDS) is the most common complication in COVID-19 patients. Close monitoring of respiratory decompensation is essential. Supplemental oxygen, high flow nasal canula, non-invasive ventilation and endotracheal intubation are the most commonly suggested methods to improve oxygenation. Early intubation with pre-oxygenation, modified rapid sequence intubation and intubation using a video laryngoscope has been advised as a strategy including lung protective ventilation, prone position ventilation, adequate sedation and extracorporeal membrane oxygenation. Strict personal precautions and challenges related to airway management has been currently studied. The authors summarize here the issues of mechanical ventilation and some strategies to resolve them

Baig, Muhammad Akbar

Sheikh, Sadaf

English

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eCommons@AKU Department of Emergency Medicine Medical College, Pakistan 6-2020 Optimising ventilator use during the COVID-19 pandemic Sadaf Sheikh Muhammad Akbar Baig Follow this and additional works at: https://ecommons.aku.edu/pakistan_fhs_mc_emerg_med  Part of the Emergency Medicine Commons, and the Virus Diseases Commons SHORT COMMUNICATIONJournal  of  the College of  Physicians and Surgeons Pakistan 2020,  Vol.  30 (Supplement 1 COVID-19):S46-S47S46Optimising Ventilator Use during the COVID-19 PandemicSadaf Sheikh1 and Muhammad Akbar Baig21Sultan Qaboos University Hospital, Muscat, Oman2The Aga Khan University Hospital, Karachi, PakistanABSTRACTHypoxemia is the most common cause for hospitalization in COVID-19 patients. Acute hypoxemic respiratory failure oracute respiratory distress syndrome (ARDS) is the most common complication in COVID-19 patients. Close monitoring ofrespiratory  decompensation  is  essential.  Supplemental  oxygen,  high  flow  nasal  canula,  non-invasive  ventilation  andendotracheal intubation are the most commonly suggested methods to improve oxygenation. Early intubation with pre-oxygenation,  modified  rapid  sequence  intubation  and  intubation  using  a  video  laryngoscope  has  been  advised  as  astrategy  including  lung  protective  ventilation,  prone  position  ventilation,  adequate  sedation  and  extracorporealmembrane oxygenation. Strict personal precautions and challenges related to airway management has been currentlystudied. The authors summarize here the issues of mechanical ventilation and some strategies to resolve them.Key Words: Mechanical ventilation, COVID-19, HypoxemiaHow to cite this article: Sheikh S, Baig MA. Optimising Ventilator Use during the COVID-19 Pandemic. J Coll Physicians Surg Pak 2020;30(Supp1):S46-S47 https://doi.org/10.29271/jcpsp.2020.Supp1.S46.Clinical spectrum of COVID-19 patients revolves around asymp-tomatic carriers, upper respiratory tract infections, pneumonia,heart  failure,  myocarditis,  coagulopathy  and  severe  forms  ofARDS.  Organ  dysfunction  including  injury  to  heart,  liver  andkidney is common in the critically ill patients.2 Patients presentedwith dyspnea, tachypnea, desaturation with oxygen saturationless  than  90%,  partial  pressure  (Pa02)  to  fraction  of  inspiredoxygen (FI02) less than 300 mmHg and lung infiltration more than50% within 48 hours.2 It was observed that relatively asympto-matic hypoxemia (‘silent hypoxemia’) may be responsible for therapid deterioration and gives a false sense of wellbeing whenoxygen  debt  is  been  asymptomatically  increasing  in  COVIDpatients. Endotracheal intubation was performed in 2.3% of 1099 COVID-19patients in China1-2 during the outbreak. Patients with cardiopul-monary arrest and acute respiratory failure due to COVID-19 wereintubated empirically in particular with those patients showing noimprovement with non-invasive ventilation, persistent respira-tory distress and poor oxygenation (PaO2 to FIO2 ratio less than150 mmHg) after 2-hours of high-flow oxygen therapy or noninva-sive ventilation.3 There is no supporting evidence towards earlyintubation  could  save  more  lives  however  many  authoritiesincluding American Heart Association, are suggesting it.3Correspondence  to:  Dr.  Sadaf  Sheikh,  Department  ofEmergency  Medicine,  Sultan  Qaboos  University  Hospital,Muscat,  OmanE-mail:  sheikh.sadaf@gmail.com.....................................................Received: April 06, 2020;  Revised: May 17, 2020;Accepted:  May  23,  2020DOI:  https://doi.org/10.29271/jcpsp.2020.Supp1.S46Studies showed that delayed decision for intubation was relatedto adverse outcomes.3 It should be used as a ‘salvage therapy’when  oxygenation  was  declining.  The  most  recent  reportshowed that, among the 22 ICU patients who were intubated, 19(86%) of them died.3  Shoemaker et al.’s work highlights theimportance of timely reduction of oxygen debt using effectiveoxygenation and ventilation therapies. Cross infection among healthcare workers were there in theearly outbreak when self-protection was not much established.Transmission mechanics are still unknown. Withholding intuba-tion may outweigh the risk of cross infection. HCW should wearpersonal protection equipment (PPE) strictly. Efficient educa-tion should be provided for donning such as hair cover, fit-testedN95 respirator, water proof gown, double gloving, eye and faceshield, and water proof shoe covers.4  An experienced assistantshould be there to check for donning and doffing process andprovide feedback. Details for doffing process were explainedincluding hand hygiene, eye and face shield removal,  gownremoval, outer glove removal, shoe cover removal, inner gloveremoval, hand hygiene, N95 respirator or equivalent removal,and hair cover removal.4 A shower and the use of oral, nasal, andexternal auditory canal disinfectants are recommended afterthe removal of personal protective equipment.When COVID-19 patient requires intubation, they have no respi-ratory  reserve  with  exhausted  compensatory  mechanisms.With  very  low  oxygen  saturation  with  loss  of  breathing  ascommon  presentation,  a  careful  airway  management  planshould  be  made.4-6  PPE  could  make  the  intubation  processdifficulty and with psychological stress of cross infection couldmake an easy intubation difficult.Sadaf  Sheikh and Muhammad Akbar BaigJournal  of  the College of  Physicians and Surgeons Pakistan 2020,  Vol.  30 (Supplement 1 COVID-19):S46-S47 S47Preparation includes oxygen, an assistant (helper),  monitor,suction,  machine  (ventilator),  airway  materials,  intravenousaccess and medications (drugs) as acronym OH–MS MAID. Withone-time use disposable supplies, an efficient airway evalua-tion should be initiated before intubation. Two single-use filtersshould be placed in the inhalation and exhalation breathingcircuits. Bacterial filters had been used for Influenza in the pastand were observed to be capable of preventing the infection.5Well-fitted facemask should be used for pre-oxygenation. Non-invasive ventilation should be used with 100% Fi02 to maximizeoxygenation. These measures yet need to show promise due togap  in  improved  oxygenation  and  unpredictable  outcomes.Although the aerosol-generating potential of noninvasive venti-lation is a potential concern to some providers,6 it is being widelyused amid this outbreak.Mechanical  ventilation  includes  low tidal  volume ventilation(4–8 mL/kg of predicted body weight), targeting plateau pres-sures of <30 cm H2O, conservative fluid strategy, a higher posi-tive end-expiratory pressure (PEEP) strategy and prone ventila-tion  for  12  to  16  hours  per  day.4-6  Neuromuscular  blockingagents are recommended to facilitate protective lung venti-lation, persistent ventilator desynchrony, deep sedation, proneventilation, or persistently high plateau pressures.4-6 Furtherrecommendations  include  head  up  positioning  (30-45°)  toimprove oxygenation and reduce risk of ventilator associatedpneumonia.Indications for early intubation has been recommended, basedon  early  COVID-19  experience  in  China.1-4  Some  patientsprogress to refractory hypoxaemia rapidly, and an awarenessthat preparation for intubation takes longer given the need forairborne/contact  precautions.  However,  reports  from  theCOVID-19  pandemic  suggest  that  some  patients  who  havesevere hypoxaemia can avoid intubation if they are otherwisestable.4-6 Pre-oxygenation should involve a tight-fitting mask.Patients refractory to pre-oxygenation (e.g. unable to achieveSpO2 >90-95%) likely have “shunt” physiology and may requirecontinuous positive pressure ventilation for preoxygenation.Risk of viral transmission is avoided further through the use ofviral filter on ventilators, rapid sequence induction with avoi-dance of bag mask ventilation (unless required for re-oxygena-tion), avoid cricoid pressure (may stimulate cough / vomitingand  worsen  view),  routine  use  of  video-laryngoscopy  andavoiding auscultating the chest post-intubation.Modified rapid sequence intubation with agents such as Mida-zolam 1 to 2 mg for anxious patients, lidocaine, 1.5 mg/Kg forcough suppression, etomidate (0.2 to 0.3 mg/Kg) for patientswith hemodynamic instability or propofol (1 to 1.5 mg/Kg) forstable  patients.  Fentanyl  (50  to  100  mcg)  may  be  used  tosuppress laryngeal reflexes and optimize the intubation condi-tion.5-6 Gentle airway manipulation is warranted. It is prudent touse video laryngoscopy rather than direct laryngoscopy for intu-bation to minimize the risk of cross infection. Same precautionsshould be considered during extubation.Due  to  lack  of  guidelines,  we  are  adopting  ARDS  guidelinesalready established for severe hypoxic patients.1-5  The widelyused practice after lung recruitment maneuvers, is to set PEEP at20 cm H2O and titrate down in a decrement of 2 to 3 cm H2O. Nomode  of  ventilation  has  been  suggested  to  be  superior  toothers.3  Awake prone ventilation or mechanical ventilation inthe prone position improves oxygenation and lung recruitment.5Further precaution could be taken for reduction of aerosol gener-ation  post-intubation  with  endotracheal  tube  cuff  pressurechecks, in-line suction and tight circuit connections.4-6It is appropriate to be conservative with intravenous fluids inpatients with severe lung injury if there are no signs of tissuehypoperfusion.2  Early  dexamethasone  administration  mayreduce overall mortality and mechanical ventilation duration inARDS  patients.5  Extracorporeal  membrane  oxygenationshowed promise in selected patients and a review suggestedmortality reduction in patients with ARDS hence can be used asa salvage options in severe hypoxemia.2-6  With acute refractoryhypoxemia, timely intubation is superior to decrease oxygendebt.CONFLICT OF INTEREST:Authors declared no conflict of interest.AUTHORS' CONTRIBUTION:SS,  MAB:  Drafted  the  manuscript  significantly  in  terms  ofconceiving, editing and reviewing.REFERENCESGuan WJ,  Ni  ZY,  Hu Y,  Liang WH, Ou CQ, He JX,  et al.1.Clinical  characteristics  of  coronavirus  disease  2019  inChina. N Engl J Med 2020; 382(18):1708-20.Ramanathan K, Antognini D, Combes A, Paden M, Zakhary2.B, Ogino M, et al. Planning and provision of ECMO servicesfor severe ARDS during the COVID-19 pandemic and otheroutbreaks of emerging infectious diseases. Lancet RespirMed 2020; 8(5):518-26.Chavez  S,  Long  B,  Koyfman  A,  Liang  SY.  Coronavirus3.Disease (COVID-19):  A primer for emergency physicians.Am J Emerg Med 2020; S0735-6757(20)30178-9.Tolksdorf  K,  Buda  S,  Schuler  E,  Wieler  LH,  Haas  W.4.Influenza-associated  pneumonia  as  reference  to  assessseriousness  of  coronavirus  disease  (COVID-19).  EuroSurveill 2020; 25(11):2000258. Yi Y, Lagniton PNP, Ye S, Li E, Xu RH. COVID-19: What has5.been  learned  and  to  be  learned  about  the  novelcoronavirus disease. Int J Biol Sci 2020; 16(10):1753-66.Thomas-Rüddel D, Winning J, Dickmann P, Ouart D, Kortgen6.A, Janssens U, et al. Coronavirus disease 2019 (COVID-19):update for anesthesiologists and intensivists March 2020.Anaesthesist 2020; 69(4):225-35.

Optimising ventilator use during the COVID-19 pandemic

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