A middle-aged man, in his 40s, showed up at the emergency covid-19 Intensive Care Unit (ICU) at a hospital in Mumbai, last year, complaining of chest pain, breathlessness and discomfort. The man was diabetic, hypertensive and obese, making him part of the high-risk category of covid patients. What helped him recover from his respiratory distress and get discharged from the hospital on the tenth day without any oxygen support, was his pro-activeness when it came to ‘proning’ or prone ventilation.
Proning, the process of turning a person suffering from breathing difficulties from the back onto the stomach (abdomen) became a familiar concept during the pandemic.
Dr Sachin Kumar, senior consultant, pulmonology and critical care medicine, Sakra World Hospital, Bengaluru, says that the prone posture involves the patient lying (face) down on pillows or lying flat on the stomach ensuring no pressure on the patient’s body. Awake proning was also recommended for people with covid, so they could lie face-down for four to five hours in their homes, he adds.
In this case, the man’s motivation to get better made a huge difference, says Dr Aparna Iyer, consultant, pulmonology, Apollo Hospitals, Navi Mumbai, who was heading a covid ICU during the height of the pandemic in India. “He was constantly dependent on the oxygen mask and was breathless all the time. So, we asked him ‘why don’t you try prone positioning?’ At first, he was very apprehensive. But once he did it, he improved pretty well. Next time, we didn’t even have to tell him. He started self-proning while he wasn’t intubated. With this, his oxygen requirement came down.”
What conditions can be treated with prone position ventilation?
Dr Ravi Kumar, consultant intensivist and head of department, ICU and critical care, Sagar Hospitals, Bengaluru, says that prone position ventilation could be used in treating people suffering from severe acute respiratory distress syndrome (ARDS is a condition where the build-up of fluid in the lungs causes inadequate oxygen supply) and those suffering from refractory hypoxemia (inadequate arterial oxygenation despite optimal levels of inspired oxygen).
ARDS: Distress signal from lungs needing urgent care – Happiest Health
Dr Ravi adds that in rare circumstances, prone position ventilation has also been used during extracorporeal membrane oxygenation (ECMO), a treatment method in which a mechanical pump and an artificial lung are used to support the patient while the lungs heal.
Dr Sunil Kumar K, lead and senior consultant, interventional pulmonology, sleep medicine and transplant physician, Aster CMI hospital, Bengaluru, recalls a case he handled. A 52-year-old male who was covid-positive, diabetic and hypertensive approached the hospital. “He required around four to five litres of oxygen through a face mask,” says Dr Sunil.
“In this case, the patient was comfortable, conscious and able to cooperate with us. In a day, we used to make him spend at least 14 to 15 hours in prone position ventilation. We were able to maintain this sort of position for at least four days. After four days, the oxygen requirement slowly reached two litres. After ten days, we were in a position to discharge the patient without oxygen,” he adds.
Research shows that prone position ventilation carried out during mechanical ventilation improved survival rates among people suffering from ARDS.
According to a study titled ‘Prone position in acute respiratory distress syndrome’ published in the European Respiratory Journal, with prone position ventilation, oxygenation improved in 70-80 per cent of patients with early ARDS.
How does prone position ventilation help/work?
Dr Iyer, while explaining how prone position ventilation helps, says that in someone suffering from ARDS, the capacity of the body to take oxygen from the air sacs and give it to the blood is reduced.
“Air sacs are responsible for transferring oxygen (from what we breathe) into the blood vessels. Unless this happens, the tissues and other organs in the body will not get enough oxygen to breathe. Because of any inflammation, such as covid or viral inflammation, inflammatory fluid gets accumulated in the air sacs. The air sacs, instead of being filled with normal oxygen, are filled with fluids and they tend to collapse more,” she explains.
Dr Iyer says that prone position ventilation works on the basic principle of redistribution. The blood flow in one’s body mainly depends on gravity. In the supine position (lying horizontally with the face and torso facing up), the blood flow gets diverted to the back.
“Gravity also causes closure of the air sacs. Hence, in the back-down position, the blood flow is not going to open the air sacs. This causes the oxygen level to drop. In the tummy-down position, the air sacs at the back will start becoming non-dependent and will start opening up. Overall, the distribution of the ventilation will improve. Once the ventilation improves, the blood will be able to absorb more oxygen from the ventilated air sacs at the back. This is the basic mechanics of how prone position ventilation works,” she says.
Challenges and contraindications
Although it can be a life-saving procedure, doctors say that one must exercise caution. While the benefits are aplenty, so are the complications and contraindications associated with the technique.
“You must be very careful because some patients will not be able to tolerate it. In case the person is complaining of heaviness or any discomfort, then don’t push it too far,” Dr Iyer cautions.
Dr Ravi says that prone position ventilation shouldn’t be carried out in cases where the person has suffered:
- Acute bleeding (eg: haemorrhagic shock, massive haemoptysis)
- Multiple fractures or trauma (eg: unstable fractures of femur, pelvis, face)
- Spinal instability
- Severe burns
- Life-threatening cardiac arrhythmias or hypotension
It should also not be initiated in cases where the person has undergone tracheal surgery or a major abdominal surgery within two weeks, is in shock (eg: persistent mean arterial pressure <65 mmHg), has raised intracranial pressure >30 mmHg, cerebral perfusion pressure <60 mmHg or has recently had a pacemaker installed.
Dr Iyer points out that once the person is in the prone position, there is a chance of pressure sores developing in some areas, particularly the face. Feeding also becomes a little challenging since usually, people on ventilators are given food through the tube that passes through the nose. Doing this while the person is in the prone position becomes technically challenging, she says.
Dr Ravi says that some of the complications associated with prone position ventilation include:
- Nerve compression
- Crush injury (the physical manifestation of prolonged compression of the torso or another body part)
- Facial edema (swelling of the face due to the build-up of fluids) due to too much pressure on the face
- Dislodging endotracheal tube
- Pressure sores (eg: facial)
- Dislodging vascular catheters or drainage tubes
- Retinal damage
- Transient reduction in arterial oxygen saturation
- Transient arrhythmias (a condition where the heartbeat is irregular and rapid)
To avoid the complications that could arise, Dr Sachin says that a team of trained and experienced critical care staff are assigned to monitor the blood pressure, heart rate and oxygen level of the person. They also watch out for bed sores that could develop.
According to Dr Iyer, prone position ventilation can help people if carried out properly.
“I handled a lot of cases where people showed improvement after proning – it can save lives at times,” she says.