Oxygen is a common medical aid because oxygen deprivation can alter the body’s function and metabolic status. However, oxygen inhalation is also “too much but not too little”, and too much oxygen may lead to lung damage.
How to use the oxygen and equipment in our hands to “save” the hypoxic state?
Oxygen inhalation method
What is the correct “posture” of oxygen inhalation?
1.Nasal plug or unilateral nasal catheter oxygen inhalation
Advantages: simple device, easy to operate.
Disadvantages: oxygen concentration is not constant, easy to block; local irritation; not tolerated by patients.
2.Mask oxygen inhalation
Advantages: large contact area, oxygen absorption effect is better than nasal plugs or unilateral nasal catheter oxygen inhalation method; no irritation, suitable for patients with open mouth whistling.
Disadvantages: facial humidity and discomfort, communication inconvenience; inconvenience to eating and drinking; mask is not disposable, need to be repeatedly cleaned and disinfected, increasing the workload and the chance of cross infection.
Warm Tips
Older masks are more suitable for patients with whistling alkalosis because they tend to cause carbon dioxide retention during oxygen inhalation.
Venturi mask (Venturi mask) is also a kind of mask oxygenation, without the use of wetting bottles, while overcoming the shortcomings of oxygen concentration is not constant, not affected by the whistling pattern, more suitable for patients with hypoxemia with hypercapnia.
3, whistle machine assisted ventilation
Advantages: hypoxemia that cannot be corrected in a short time, consider the establishment of an artificial airway to facilitate airway management by health care workers.
Disadvantages: increases the chance of nosocomial infection.
Oxygen concentration
What is the correct “posture” of oxygen inhalation?
1.Oxygen intake purpose
To increase the partial pressure of arterial blood oxygen and oxygen saturation, to increase the content of arterial oxygen, to correct the state of hypoxia caused by various reasons, to promote tissue metabolism, and to maintain the vital activities of the body.
2.Oxygen flow rate
Including low flow rate 1-2 L/min, medium flow rate 2-4 L/min. below 1L/min, the oxygen flow rate is too low to effectively play a therapeutic and health care role.
The oxygen concentration (FiO2%) is inseparable from the oxygen flow rate, the oxygen concentration in the air is 21%, the conversion relationship between the two is: FiO2%=(21+4×oxygen flow rate)%
In other words, the oxygen concentration is 33% when the oxygen flow rate is 3 L/min, and similarly, the oxygen concentration is about 40% when the oxygen flow rate is 5 L/min. High oxygen concentration means that the concentration of inhaled oxygen is more than 50%.
The control of oxygen concentration and time is the most critical measure to avoid the side effects of oxygen therapy.
(1) Inhaled oxygen concentration <28%, even if the oxygen is inhaled for a long time, no side effects and danger will occur.
(2) Inhalation concentration of oxygen > 50%, the time should not exceed 48 hours.
(3) Inhalation of oxygen at a concentration of 60%-80% should not exceed 24 h. Oxygen inhalation should not exceed 4-6 h.
3.Pulmonary oxygen toxicity
The lung is the organ with the highest oxygen concentration and oxygen partial pressure. Long time high concentration oxygen inhalation (e.g. after 1-2 days of oxygen inhalation of 60% or more concentration) is most likely to produce too much reactive oxygen, causing lung damage and oxygen toxicity.
The manifestations are retrosternal discomfort, chest pain, cough (in severe cases, it can be spasmodic), mucous sputum or bloody foamy sputum, shortness of breath, chest tightness, and dry and wet rales can be heard in both lungs.
Warm Tips
The main cause of death in paraquat poisoning is pulmonary fibrosis leading to lung failure, and oxygen inhalation will lead to the aggravation of pulmonary fibrosis, so oxygen inhalation is generally not recommended in paraquat poisoning.
Determination of efficacy
What is the correct “posture” of oxygen inhalation?
After 10-30 min of oxygen administration, the patient’s heart rate and whistling rate will slow down, the consciousness will improve, and the finger pulse oxygen will increase to 95% or more.
Oxygen therapy is effective if the partial pressure of oxygen rises or the partial pressure of carbon dioxide falls on arterial blood gas analysis.
Blood gas analysis is the most reliable method to determine whether oxygen is effective. Observe the change of oxygen partial pressure index on blood gas analysis and adjust the oxygenation plan in time.
Whistler assisted
What is the correct “posture” of oxygen inhalation?
1.Non-invasive whistle machine (NPPV)
Patients with mild ARDS without obvious contraindications can try non-invasive positive pressure ventilation (NPPV) with a non-invasive whistle machine, and invasive mechanical ventilation with tracheal intubation as soon as possible if it is not effective or if the condition worsens.
The main measures include low tidal volume and appropriate positive end-pulmonary pressure ventilation (PEEP).
The end-of-whistle positive pressure ventilation starts at a low level of 5 cm H2O and gradually increases to an appropriate level, aiming to maintain partial pressure of oxygen above 60 mmHg and FiO2 less than 60%.
Warm Tips
To avoid delays, unless a senior physician or a physician with actual experience in non-invasive ventilation, invasive mechanical ventilation should be performed as soon as the patient is diagnosed with ARDS.
2. Invasive mechanical ventilation
Tracheal intubation is indicated for patients with upper whistle obstruction, impaired protective airway mechanisms, airway secretion retention and whistle failure.
Tracheotomy needs to be considered in patients with poor autonomic sputum evacuation and who cannot be decannulated within a short period of time.
Before intubation, the patient should be adequately oxygenated, positioned so that the oropharynx and trachea are in a straight line, and manually ventilated so that the patient’s fingertip oxygen saturation is above 95% before intubation is performed.
The oxygen concentration was initially set at 100% for the initial setting of the whistler ventilation parameters and later adjusted according to the arterial blood gas analysis SpO2.
Similarly, the oxygenation status of the patient is one of the criteria that must be taken into account when considering withdrawal.
Before withdrawal, it is required that the oxygen concentration is below 40%, the oxygenation index is not less than 200 mmHg, and the fingertip oxygen saturation is not less than 94%.
Common diseases
What is the correct “posture” of oxygen inhalation?
1.COPD – Long Term Oxygen Therapy
Long-term oxygen therapy (LTOT) can improve the survival of patients with COPD with chronic whistle failure, meaning that patients with chronic hypoxemia are on daily oxygen for a longer period of time.
Indications: LTOT can be administered with or without hypercapnia when whistle failure is stable for 3-4 weeks and PaO2 ≤ 55 mmHg or SaO2 ≤ 88%.
PaO2 55-59 mmHg and the presence of pulmonary hypertension, pulmonary heart disease, erythrocytosis or nocturnal hypoxemia are also indications for LTOT.
Oxygen administration criteria: oxygen flow rate of 1.5-2.5 L/min, oxygen for 24 h daily, at least 15 h daily to maintain PaO2 > 60 mmHg, taking into account patient compliance.
Warm tips
Patients with chronic lung disease are in a state of relative hypoxia for a long time, and their inspiratory movements are mainly maintained by hypoxic stimulation of peripheral chemoreceptors.
When the oxygen concentration inhaled by the patient is too high, the partial pressure of oxygen in the blood rises for a short period of time, resulting in the disappearance of the “hypoxic” factors that stimulate whistling, and the patient may experience progressive whistling difficulties or even stop whistling.
Therefore, COPD patients and patients with chronic pulmonary heart disease are not suitable for inhaling high concentrations of oxygen.
2.Patients with heart failure
Oxygen therapy can be used for acute heart failure, and is not indicated for chronic heart failure.
In patients with heart failure without pulmonary edema, oxygen administration can lead to hemodynamic deterioration, but in patients with heart failure with sleep whistling disorder, noninvasive ventilation plus low-flow oxygen administration can improve hypoxemia during sleep.
Oxygen is required in acute heart failure with hypoxemia and significant dyspnea, especially in patients with pulse oximetry below 90%.
It should not be used routinely in the absence of hypoxemia because it may lead to vasoconstriction and decreased cardiac output at the same time.
If oxygen is needed, it should be used as soon as possible to achieve an oxygen saturation of ≥95% (90% with COPD is acceptable).
Oxygen can be administered by nasal cannula or face mask (for patients with whistling alkalosis). Non-invasive or organ-intubated whistler-assisted ventilation may be used when necessary.
Well, do you remember all the knowledge about oxygenation? It does not matter if you do not remember, look at the following poem!
Oxygen inhalation oxygen is very simple, oxygen concentration in mind.
Too low and too high injury, blood gas analysis to measure.
Hypoxic state oxygen rescue, Bacopa monniera can not have.
Heart failure slow obstruction pulmonary edema, oxygen concentration leisurely use.
In fact, I can not whistle machine, oxygen concentration slowly low.