Oxygen therapy in covid 19 infection Objectives Review

Oxygen therapy in covid 19 infection

Objectives • Review the use of oxygen therapy • Respiratory assessment and management

Glossary • Fi. O 2 – the fraction of oxygen in the breathe taken eg the fraction of oxygen in room air is 21% oxygen. Oxygen supplementation increases this %. • Oxygen saturation – the %age to which peripheral blood is oxygenated. • Sp. O 2 – peripheral capillary oxygen saturation measured by oxygen probe. • Hypoxaemia – low level of blood oxygen. • Type 2 respiratory failure – hypoxaemia with high CO 2 eg in COPD.

Normal respiratory parameters Respiratory rate 12 -16 breaths per minute – measure for 1 minute Regular breaths, normal depth Sp 02 >96% Patients are: -warm and well perfused -able to speak without becoming breathless -look comfortable -able to cough and clear secretions

Normal oxygen saturation range in healthy adults • Healthy adult - daytime • Sp 02 = 96 -98% • Type 2 respiratory failure • Sp 02 = 88 -92% • Transient dips in saturation are common during sleep • KNOW YOUR PATIENTS

Important points to consider about oxygen therapy • Oxygen is a life saving drug for hypoxaemic patients. • Aim is to achieve Sp. O 2 92 -96%, higher may be harmful. • Service users with Type 2 Respiratory Failure may be harmed by too much oxygen as this can lead to increased carbon dioxide (CO 2) levels and respiratory depression (less than 10 breaths per minute)

Oxygen is a drug and should be prescribed except in emergencies • Oxygen should be regarded as a drug (BNF 2017) • Oxygen must be prescribed in all situations ( but you must start oxygen if a prescription is not yet available in the immediate management of critical illness in accordance with BTS guidelines –DO NOT DELAY STARTING OXYGEN IN A DETERIORATING PATIENT) (NPSA Oct 2009) • Oxygen prescription should give a target saturation (Sp. O 2) and delivery type (eg nasal cannula) and should be written on the drug chart (BTS 2017)

Equipment for oxygen therapy • Be familiar with your oxygen supply, how to open and how to replace cylinders. • Be aware of the oxygen devices available in your area. • Make sure that training in NEWS 2 is up to date.

Oxygen Cylinder Set Up

Oxygen devices Whats this… This is the non- rebreathe mask or high concentration mask with reservoir Why use this… Emergency, acute or peri arrest situations allows delivery of Fi. O 2 85 -90% oxygen How to use this… -Oxygen flow 15 l/min -The mask valve should be covered to ensure the bag inflates -Should escalated to the medical team for urgent review What is this… This the venturi system Why use this… Allows delivery of more precise oxygen How to use this… -The different coloured valves indicate how much oxygen the patient is on and the flow rate required, particularly useful for type 2 respiratory failure. What is this… This is a medium concentration mask or simple face mask Why use this… Similar to nasal cannual and can deliver upto 50% of oxygen however isn’t precise. How to use this… The flow rate cannot be any less that 5 litres otherwise possible CO 2 rebreathe 5 -6 litres administers around 35% 7 -8 litres administers around 40% 9 -10 litres administers around 50% What is this… This is a nasal cannula Why use this… Comfortable, patient able to eat and speak easily, How to use this… Delivers: 1 litre administers 24% 2 litres administer 28% 3 litres administer 32% 4 litres administer 36%

Possible clinical scenarios • Acute worsening with hypoxaemia • Mild hypoxaemia, “not for transfer” and palliative care. • Step down from general hospital.

Acute worsening - warning signs of deterioration • Respiratory rate >20 breaths per minute • Using accessory muscles • Sitting forwards bracing themselves (tripoding) • Struggle to clear phlegm/sputum • Sa. O 2 <92% on air • New distress or anxiety

Management of a severely ill patient • Where Sp. O 2 below 92% and not responding to 4 l/min via nasal cannula or >5 l/min via simple mask • Red flag symptoms present • NEWS 2 >4 or score in single parameter 3 • Consider using non-rebreathe mask and refer to doctor to review possible escalation to critical care

Red flag symptoms • New confusion or drowsiness • Unable to talk in a full sentence • Needing increasing levels of oxygen via nasal cannula or mask to maintain saturations • Rapidly deteriorating NEWS 2 score • Becoming short of breath on minimal exertion • Start 15 L o 2 via non-rebreathe mask and call doctor

High Concentration Non–rebreathe Mask (NRB) • Used in critically ill patient and where Sp. O 2 remains below 90% despite O 2 therapy via nasal cannula or mask. • Post-cardiac or respiratory arrest • Delivers Fi. O 2 of 85 -90% or above (flow meter must be set at 10 -15 litres) • Effective for short term treatment until doctor can review

Management of deterioration • Use ILS training – think ABCDE • FULL NEWS 2 paying attention to respiratory rate (time for full minute), pulse & O 2 saturation has it altered from the baseline? • If Sp. O 2 < 92% or below the individuals baseline commence oxygen 4 l/min via nasal cannula or 5 l/min via simple face mask and increase flow to achieve target Sp. O 2. • After initial assessment titrate O 2 to 92 -96% or 88 -92% in patient with type 2 respiratory failure • Monitor O 2 saturation every 15 minutes – looking for improvement or deterioration. • Inform medical staff - use SBAR

Mild hypoxaemia, “not for transfer” and palliative care • Use low flow delivery system eg nasal cannula, simple mask or venturi mask to achieve target Sp. O 2. • Supplementary oxygen does not relieve breathlessness unless hypoxaemia is present. • In palliative care use of medications eg morphine are usually effective in controlling breathlessness.

Simple Face Mask • Simple semi rigid face mask • 5 l/min Fi. O 2 40% • O 2 flow rate should be at least 56 l to prevent re-breathing C 02 • Patients may feel claustrophobic and eating and drinking may be impaired

Nasal Cannula • Recommended for most people on long term/intermittent O 2 therapy • 2 L/min gives approx. Fi. O 2 28%, 4 l/min 36% • Comfortable and easily tolerated • No re-breathing • Can eat/drink/talk • Preferred by patients (Vs simple mask)

Venturi or Fixed Performance Masks (V) • Aims to deliver constant oxygen concentration • Good masks for patients with Type 2 respiratory failure because Fi. O 2 precise • (patients with a target Sp. O 2 of 88 -92%) • • • Blue White Yellow Red Green = 24% @ 2 litres = 28% @ 4 litres = 35% @ 8 litres = 40% @ 8 litres = 60% @ 15 litres

Precautions • When patient using oxygen it is essential to check regularly the oxygen level in the cylinder (every time NEWS 2 are recorded) and to know how long it will take for cylinder to empty • CD cylinder last 90 minutes @ 5 l/min, ZX 10 hours @ 5 l/min • Remember O 2 is flammable

Summary • Know your service users – anyone at particular risk. • Find out where your stock of supplies and oxygen are stored. • Know who is there for support if you feel out of your depth. • Keep calm – but act with urgency. Ask for help if you need it.

In Summary…. . • Oxygen is a drug & should be prescribed (except in emergencies) with a target saturation • Sick and deteriorating service users must not go without oxygen while waiting for a medical review or paramedics • In an emergency, use a Non-rebreathe mask with O 2 @15 litres • Sick and deteriorating service users with Type 2 Respiratory Failure must receive O 2, with a target saturation of 88 -92%. • It is your responsibility to familiarise yourself with the O 2 delivery devices and O 2 cylinders available in your area of work

Summary • Reassure • NEWS 2 and fluid balance chart • O 2 if required –(prescribed) • Promote and assist with healthy fluid intake & monitor • Communicate with medical staff regularly and agree plan of action. • Involve Physical health team - or other more experienced staff if unsure. Ask for help. • Discuss vulnerable patients at handover • Document all actions on Paris