Why is ppe necessary for ards

Williams, J. Powell, A. Physiological impact of the N95 filtering facepiece respirator on healthcare workers. Respir Care, 55 , pp. Li, H. Tokura, Y. Guo, A. Wong, T. Wong, J. Chung, et al. Effects of wearing N95 and surgical facemasks on heart rate, thermal stress and subjective sensations. Int Arch Occup Environ Health, 78 , pp. Shortly after intubation, he was placed on pressure control ventilation with a driving pressure of 15 cmH 2 O and a positive end expiratory pressure PEEP of 15 cmH 2 O.

As such, he was placed on a neuromuscular blocking agent NMBA for patient-ventilator asynchrony. The patient's medical history included class III obesity, hypertension, depression, anxiety, recreational drug use cocaine and opioids and previously undiagnosed diabetes diagnosed after admission to ICU. His home medications consisted of candesartan, escitalopram, ariprazole and trazodone.

A plain film chest radiograph was performed, which was reported as bilateral alveolar infiltrates with consolidation Figure 1. His arterial blood gas after intubation showed a pH of 7. Table 1: Clinical laboratory results throughout duration in the Intensive Care Unit. View Table 1. Figures are lettered in consecutive order. View Figure 1. A nasopharyngeal swab specimen was obtained in the emergency department and sent for detection of viral respiratory pathogens by real-time polymerase chain reaction PCR for SARS-CoV 2 Envelope gene; this was reported back as positive within 24 hours in a laboratory in the local region.

Due to persistent hypoxemia, he was then transferred to the ICU of a dedicated COVID community hospital in the same region on the same day of his emergency room presentation for further care. The patient was placed in a negative pressure room and airborne precautions were undertaken by all healthcare workers. A conservative fluid strategy was adopted in the management of this patient to maintain the patient near euvolemic status.

This patient was weaned off the vasoprrossor on the second day of ICU admission See Table 2, for details of his vitals and vasopressor medication. Table 2: Daily vitals and vasoactive agents administered during his first day stay in the Intensive Care Unit. View Table 2. He was deeply sedated with continuous infusion of propofol, midazolam and fentanyl. He was also placed on continuous infusion of a NMBA, cisatracurium, to aid in patient-ventilator synchrony.

A proning procedure was undertaken daily for 16 hours for four days for severe hypoxemia. Table 3: Ventilatory settings, positioning and associated medications during the patient's first day stay in the Intensive Care Unit. Evidence supports a marked cytokine release in COVID infection, directly related to the severity and mortality of the disease, and this is reflected by high levels of interleukin-6 IL-6 , ferritin and C-reactive Protein CRP [ 11 , 12 ].

COVIDrelated Hypercoagulability: A distinct prothrombotic state as opposed to a consumptive coagulopathy has been described in COVID patients, secondary to a markedly increased levels of fibrin and fibrinogen. This mechanism is synergistic with the cytokine storm and the virus-induced endothelial dysfunction.

Consequently, serum levels of D-dimer are a strong prognostic factor of poor outcomes [ 12 , 13 , 14 ]. CRP has been found to be consistently elevated in patients with COVID infection and shares an inverse relationship with oxygen requirement levels, and may be used for mortality prognostication [ 20 , 21 ].

Procalcitonin levels are moderately elevated in these patients and have not been consistently associated to predict mortality of the disease [ 19 ]. In addition to the reverse-transcription polymerase chain reaction RT-PCR for COVID, routine blood cultures and viral panel should be sent to rule out the presence of any other microorganism as a main culprit or as co-infection [ 23 ]. Zhou et al. Lung ultrasound in patients with COVID pneumonia has also been described and its findings appear to correlate satisfactorily with the CT findings.

Peng et al. Thickening of the pleural line as well as pleural effusions have been described [ 28 ]. Environmental control is paramount to be considered in the initial approach to patients with COVID pneumonia. Droplet precautions have been advocated by multiple organizations. The World Health Organization and the Australian and New Zealand Intensive Care Society recommend airborne precautions when aerosol-generating procedures are expected in COVID patients, including: face mask ventilation, non-invasive ventilation, endotracheal intubation, open airway suctioning, aerosolized medications, bronchoscopy, disconnection of the patient from the ventilator and cardiopulmonary resuscitation.

Despite the high risk of contamination during these procedures, current evidence suggests that meticulous use of personal protective equipment is effective to prevent infection among healthcare personnel [ 29 , 30 , 31 ]. Monitoring respiratory drive and effort are essential in spontaneously breathing patients to detect early stages of respiratory fatigue. Although non-invasive ventilatory NIV maneuvers have been employed in patients with COVID pneumonia and the literature regarding the adequate timing for intubation is controversial, most authors agree that in the presence of impaired respiratory mechanics, worsening of respiratory acidosis and most importantly decreased mental status, endotracheal intubation and mechanical ventilation should not be delayed [ 7 , 32 ].

For spontaneously breathing patients with mild-to-moderate dyspnea and hypoxemia, non-responsive to regular low-flow nasal cannula, initial approach may involve the use of high flow nasal cannula HFNC and awake prone positioning based on limited clinical data.

HFNC, although initially controversial due to its aerosolizing potential, it was found to be safe in further studies, with a bio-aerosol dispersion not significantly different from regular nasal prongs [ 33 ]. Airborne precautions among the treating staff should be maintained and the patient should be placed in a negative pressure room if available [ 29 , 30 , 34 ].

Yang et al. NIV support continuous positive airway pressure [CPAP] or Bi-level positive airway pressure [BiPAP] has been employed in COVID patients as a last resource to circumvent endotracheal intubation after failing HFNC and awake prone positioning, although no formal recommendation regarding their use has been released due to the risk of aerosolization [ 29 ].

This latter has been found to be more appropriate for specific certain group of patients with other concomitant co-morbidities i. The use of bronchodilators should be minimized and instead nebulization metered dose inhalers should be employed [ 30 ]. Institution of endotracheal intubation and mechanical ventilation should be made as soon as possible regardless of the phenotype of the COVID pneumonia, when signs of respiratory distress are associated to the severe hypoxemia.

The following ventilatory strategies represent an expert opinion, based on current and rapidly evolving evidence in patients with CARDS, therefore further data is required to confirm the efficacy of these maneuvers. Gattinoni et al. The aim is to avoid ventilator-induced lung injury by reducing lung and vascular stress [ 32 ]. Lung recruitment was more evident after prone positioning in the population analyzed [ 39 ].

Airway pressure release ventilation APRV may be considered early in the course of intubated patients with moderate to severe ARDS, in order to provide adequate alveolar recruitment. The application of APRV continues to be limited, given that many providers are not familiar with this ventilation mode or its titration methodology [ 40 ]. Pan et al. The main obstacle continues to be its implementation and generalization among each institution. Trained and qualified nursing and respiratory therapy staff is the most important factor to obtain successful results, as severe life-threatening events may occur at any given time self-extubation, hemodynamic instability, lack of adequate sedation, pressure ulcers [ 29 , 30 ].

In regards to neuromuscular blockade, in an effort to avoid ventilator dyssynchrony, adjust tidal volumes and decrease airway resistance with the goal to decrease lung parenchyma inflammation, neuromuscular blocking agents were introduced as part of the alternative therapies for severe ARDS [ 42 ].

No formal clinical trial or body of evidence has been published yet regarding the use of neuromuscular blockade in patients with CARDS. The Surviving Sepsis Campaign recommends the use of intermittent doses of neuromuscular blocking agents to facilitate lung protective ventilation in COVID patients [ 29 ].

The effect seemed to be more prominent in patients on mechanical ventilation number needed to treat: 8 and intermediate in those who required supplemental oxygen only number needed to treat: The trial did not show any benefit from Dexamethasone in patients who did not required respiratory support [ 43 ]. Selective pulmonary vasodilation is thought to improve ARDS secondary to redistribution of blood from poorly ventilated areas to those with higher ventilation, thereby decreasing the shunt fraction and correcting hypoxemia.

Experimental and repurposed therapies that stand unsupported by strong evidence are to be strongly discouraged. In an, observational study by Joshua et al. It has now been stopped due to lack of efficacy. Two clinical trials Japan, USA and a phase-3 clinical trial in India using favipiravir combined with another antiviral agent, Umifenovir are ongoing[27].

Results are awaited. Currently, several phase-3 clinical trials are evaluating it for treatment of moderate and severe COVID However, the RECOVERY trial with over 11, patients enrolled from over NHS hospitals in the UK provided clear evidence that dexamethasone 6mg per day for up to 10 days reduces day mortality in COVID patients receiving invasive mechanical ventilation by one third, and by one fifth in patients receiving oxygen without invasive mechanical ventilation.

No benefit was demonstrated in hospitalized COVID patients who were not receiving respiratory support and results were consistent with possible harm in this group[32]. Data from a study in USA involving 20, patients transfused with COVID convalescent plasma demonstrate that its use is safe and carries no excess risk of complications and supports the premise that administration of the same early during illness is likely to reduce mortality[33].

Another study by Liu et al showed that convalescent plasma transfusion improved survival in non-intubated patients but not in intubated patients[34]. The FDA states that it is important to determine its safety and efficacy via clinical trials before routinely administering convalescent plasma to patients with COVID However, presently there is inconclusive data to recommend for or against the use of IL-6 inhibitors[35].

Routine use of iNO in patients with COVID pneumonia is not recommended and the trial is recommended only in mechanically ventilated patients with severe ARDS and hypoxemia despite other rescue strategies[37]. Studies are ongoing to evaluate for the efficacy and safety of iNO in SARS-CoV-2 patients requiring supplemental oxygen before the disease progresses to necessitating mechanical ventilatory support[38].

Various countries have given permission to start clinical trials for vaccines being developed by them, e. It is therefore imperative to constantly monitor patients for the development of ARDS as the day of infection progresses.

The primary strategy for COVID patients is supportive care, which includes oxygen therapy for hypoxemic patients. High-flow nasal cannula HFNC for HFNO is effective in improving oxygenation, but due to reports of high amount of aerosol dispersion it was not recommended initially. However further studies in patients with acute hypoxemic respiratory failure, HFNC was proven to avoid intubation compared to conventional oxygen devices, and the scientific evidence of generation and dispersion of bio-aerosols via HFNC showed a similar risk to standard oxygen masks.

This requires a targeted lung-protective ventilation strategy to improve the outcome. Patient with multi-organ failure, persistent hemodynamic instability requiring vasopressor support, or those with multiple comorbidities like DM, Cardiovascular disease, hypertension, advanced age, frailty, cancer or chronic respiratory disease.

High respiratory rate with persistent thoraco-abdominal asynchrony or paradoxical respiration. The indications for intubation and mechanical ventilation in COVID patients are not limited to the above mentioned conditions and it should be at the discretion of the treating physician [45].

Airway management and intubation in COVID patients is an aerosol generating procedure and is associated with increased risk of viral transmission to the health care providers. Hence, a high level of attentiveness and alertness is necessary to prevent infection when intubation is performed.

The following points are to be ensured for safety of patients and health care providers[46]:. Standard monitoring, IV access, instruments, drugs, ventilator, and suction should be pre- checked. Tracheal intubation to be performed by the most experienced anaesthesiologist in an airborne infection isolation room to ensure patient safety and HCW Health care worker. Spontaneous ventilation to be preserved and avoid assisted bag mask ventilation during preoxygenation.

Use both hands to hold the mask to ensure a tight seal using the V-E technique rather than the C-E technique with one hand. After tracheal intubation, clamp the endotracheal tube ETT and inflate the cuff before instituting ventilation[48]. Avoid auscultation to confirm tube placement. Therefore, oesophageal pressure measurement by manometer can be considered in spontaneously breathing, non-intubated patients to decide the time for intubation[49]. The oesophageal pressure between 05 to 10 cm H 2 O is usually well tolerated.

If oesophageal manometry is not available, then change in CVP central venous pressure with respiration or clinical assessment of excessive inspiratory effort for increased work of breathing can be considered[50]. Inappropriate ventilatory strategy in ARDS patients can lead to VILI ventilator induced lung injury , which includes barotrauma high airway pressure , volutrauma, atelectrauma, biotrauma, myotrauma diaphragmatic injury and oxytrauma oxygen free radicals.

This approach of ventilation in patients with ARDS is based upon several randomized trials and meta-analyses that have reported survival benefit from lung protective ventilation. Initial ventilatory settings for these patients are recommended as below. If compliance is high or normal with the existence of hypoxemia, it is recommended to use a PEEP of less than 10 cm H 2 O to avoid over-distention of normal healthy alveoli.

Once the initial setting on the ventilator is entered, monitoring of the following parameters is done to ascertain patient progress:. Driving pressure is kept below 15 cm H 2 O. This can be achieved by either decreasing tidal volume at the risk of development of hypercapnia or by increasing PEEP, which can cause over-distention of alveoli. Therefore, careful titrations are required. Low compliance is usually found in ARDS patients with stiff lung.

There are two types of lung compliance:. Static compliance measures pulmonary compliance when no airflow such as during inspiratory pause and it is slightly higher than dynamic compliance. It represents pulmonary compliance during active inspiration and depends upon peak inspiratory pressure PIP.

PIP depends on airway resistance. Airway occlusion pressure PO. However, in mechanically ventilated patients, values above 3. Subsequent ventilatory setting can be decided by periodic checking of P plat pressure, driving pressure, compliance, and ABG pH, oxygenation level. The use of adjunctive treatment is relatively less during initial presentation in patients with ARDS, but gradually increase with ARDS severityrecognition, management, and outcomes of patients with the acute respiratory distress syndrome ARDS.

A combination of multiple agents like propofol, ketamine, fentanyl, morphine, hydromorphone, dexmedetomidine and midazolam may be considered for sedation of COVID patients on mechanical ventilator. Can be used in boluses in patients with refractory hypoxemia or ventilator asynchrony to facilitate protective and improved lung ventilation. It also causes reduction of high pulmonary inflation pressures e.

However, there are contradicting reports on the use of the same. Conservative or restricted fluid therapy over liberal fluid is advised, as it may worsen oxygenation in mechanically ventilated ARDS patients. If no fluid response occurs OR signs of fluid overload appear like crackles on auscultation, then discontinue the fluid and consider using vasopressors. These vasopressors to be given as per strictly controlled rate decided as per targeted blood pressure to maintain tissue perfusion.

However, peripheral lines can be considered in resource-limited settings keeping a close watch for necrosis of skin or extravasation of vasopressors. In COVID patients good response to prone positioning may be due to their well-preserved lung compliance compared with patients who develop ARDS from other causes[48],[54].

The two most commonly used vasodilators in mechanically ventilated patients are inhaled nitric oxide gas NO and Epoprostenol , which are administered by continuous inhalation. If there is no improvement in the oxygenation after instituting inhaled pulmonary vasodilators, then it should be tapered off without undue delay.

That is why inhaled NO is preferred over epoprostenol. Its use as rescue therapy is considered only in refractory hypoxic respiratory failure[56].

But the process and outcomes have not been mentioned[57]. Special focus needs to be ensured to avoid viral transmission to the health care providers during extubation as it is also an aerosol generating procedure. Since there is a high chance for reintubation in many patients, some physicians like to use cuff leak test criteria along with spontaneous breathing trials SBT.

This is done to assess the readiness for weaning from mechanical ventilation on the assumption that these patients could have developed airway oedema due to prolonged ventilation. Aerosol generation in cuff leak test is similar to extubation, so caution needs to be taken while performing a cuff leak test. SBT without T-piece at lower pressure support cm H 2 O and along with prior use of steroid to extubation yielded promising results.

The following weaning criteria is recommended before extubation:. No signs of increased work of breathing or respiratory distress like use of accessory muscles, paradoxical or asynchronous respiration, nasal flaring, profuse diaphoresis, agitation, tachypnoea, tachycardia and cyanosis.