Coronavirus ICU Experiences from Dr. Peng Zhiyong
Dr Peng is director of Intensive Care Unit of Zhongnan Hospital of Wuhan University, he encountered Covid-19 in early January, and fought in the front line in Wuhan since then.
Faced with an unknown virus, sharing and collaboration are the best remedy. We thank Dr Peng and all healthcare workers in China who have provided experiences, and hope to share this Q&A with medical professional around the world and save lives.
TESTING AND DIAGNOSIS
1. How to avoid false negative? Some say that the nose is more preferable for swab sampling than the throat, what is your recommendation?
Samples from the lower part of the respiratory tract are better, but harder to obtain. And samples from the nose have quite low sensitivity compared with samples from the lower part of the respiratory tract.
2. What markers were most sensitive and specific to predict early which patient will improve or deteriorate?
We monitor the IL-6 level of patients. If the IL-6 level is high it often indicates higher severity or worse outcome. Another simple marker is, if the patient has persistent lymphopenia, with very low absolute count, this also indicates bad outcome.
3. Can you clarify the rate of co-infection with another virus for patients with confirmed COVID-19?
Actually one team from our hospital are studying this. They use a better method for detecting influenza. There’s probably a high rate of co-infection with the influenza virus, but I don’t know the result yet. Also we do check for flu. Negative flu test is one of the criteria for diagnosis of COVID-19. But most patients we checked were negative for flu.
4. Is there any evidence that putting patients in prone position has an impact?
Prostrating patients is quite important to improve the oxygenation. We prostrate patients relatively a longer time compared with other ARDS patients. Because if only be done in short time, we could not find any improvements. So we prostrate patients as early as possible, even if they are still conscious.
5. Is high-flow oxygen a better device for respiratory failure?
We are concerned about safety and highly recommend high flow used only in the ICU with negative pressure. We monitored the virus level between the ICU with negative pressure and the regular. In the regular ICU, we detected virus on the equipment, on telephone and in the air. It is not safe for medical professionals to work within regular ICU.
6. What is the experience with non-invasive ventilation?
We should carefully monitor how the patient response to non-invasive ventilation. If the patient conditions don't improve for some time (e.g. 2 hours in our ICU), then we probably need to switch to invasive ventilation. Because the non-invasive ventilation will probably worsen the lung injury.
7. Besides ARDS, is there significant other organ injury with COVID-19, in particular ventricular dysfunction, pulmonary hypertension, encephalopathy, secondary bacterial co-infection?
Most critically ill patients with COVID-19 had complications. Almost 60% of the patients were complicated with heart injury, which can lead to pulmonary hypertension causing Acute cor pulmonale. Up to 20% of the patients were complicated with acute kidney injury.
8. Are there any therapies for the critically ill patients with ARDS that appeared beneficial or harmful?
If we use the lung recruitment maneuver, the high PEEP can induce lung injury, so we should be cautious and keep PEEP less than 20 cmH2O.
9. Any restrictions on rescue therapies for refractory hypoxemia in ARDS?
For severe hypoxemia, we most likely would use ECMO. Before ECMO, we should look at their pulmonary compliance. If the pulmonary compliance is less than 20, I don’t think ECMO will be beneficial. Also, we should watch for hypercapnia. PaCO2 over 80 predicts poor prognosis and the patient will probably be difficult weaning off ECMO.
10. Any strategies on how to manage the cardiac complications of the ICU patients?
To prevent cardiac injury, we should focus on correcting the severe hypoxemia as soon as possible. The cardiac injury is induced by severe hypoxemia.
11. What does “time-limited trial” of mechanical ventilation mean in this context? When does death seem inevitable?
This is an issue in patients with severe complications induced by hypoxemia, such as severe brain injury, severe acute kidney injury requiring dialysis, or multiple organ failure, especially in patient with many comorbidities, age over 80, or in multiple organ injury requiring organ supports. But actually we do not have a law to tell us the length of treatment trial in the different situations.
In addition, we also evaluate the severity of their lung injury. Similar consideration should be given if the lung compliance is very low, it will be difficult for the patients to be weaned off from ventilator or ECMO. If the patients are quite young and without any other organ injury, we will use ECMO as a bridge to lung transplantation. This is one option.
12. What is the survival rate for ECMO patients? What is the true survival of ventilated patients?
Actually we haven't observed these patients for very long. I could say that the weaning from the ECMO was in around 50% of the patients. But because some patients are still in the hospital, I will say that the overall mortality is probably more than 50%. I say so because I cannot guarantee these patients who are still in the hospital will survive.
The average duration of ECMO is around 7 days for the surviving cases. But for the non-surviving cases, it's much longer, around 20 days. And the average age of our patients on ECMO is around 60 years old.
13. What is the proportion of ECMO patients received VV vs. VA ECMO?
Most of the ECMOs in my ICU are VV ECMOs, almost 90%. Only one or two are on VA ECMOs, because the patients are complicated with severe shock. We switched to VA ECMO (from VV).
14. For the small number of patients requiring ECMO or prolonged mechanical ventilation, how did you decide on criteria (limited resource)?
Just as I mentioned before, we consider patients with severe complications, such as the severe brain injury or lung dysfunction measured by low lung compliance as irreversible. So these patients may be difficult weaning from ECMO. If the patients only have lung injury, with no other organ injuries, and they are young, then we will evaluate the possibility for lung transplant, and will use ECMO as a bridge.
15. Any data on characteristics and outcomes in immunosuppressed patients, such as transplant patients or cancer patients?
It's true. We also manage organ recipient patients infected with COVID-19. Regarding outcome, if the patients still stay in the hospital, within 30 days postoperatively, and gets infected by COVID-19, the outcome will be really bad. But if the patient with organ transplantation has returned to community (for example, in home or in other places), and the transplantation was long time ago, the outcome will depend on the patient's condition. Most of the patients are doing ok. For the cancer patients, if the patients are on chemotherapy or radiotherapy, they are easily infected by COVID-19. Also the severity will depend on the overall situation. If the situation of the patient is bad, and he has to be admitted, the outcome will be poor.
Regarding the patients with organ transplants compared with other patients --- this kind of patients have more severe immune disorders or severe immune suppressions. We can see severe lymphopenia and much lower CD4/CD8 ratio, compared to general population. But actually I haven't seen any patients with stem cell transplantation. I have only seen patients with solid organ transplantation.
16. What is you experience with caring for patients under 18 years old?
We did not care for any patients under 18 years old.
17. How to organize the team with non-critical-care-trained physicians?
Our solution was to set up temporary ICUs. At the beginning of the outbreak, a huge number of patients rushed to the hospital and a lot of them required ICU care. We did not have enough ICU beds. So our solution is to set up temporary ICUs. I recruited physicians from other specialties with similar trainings, like anesthesiologists, cardiologists, pulmonologists, etc. These specialists followed us for round and managing patients like critical care fellows. We also recruited nurses using the same way. It seems this approach worked well in this specific situation.
18. Knowing what you know now, is there anything you wish you could have done differently? What was the toughest choice you’ve had to make in the last two months?
I would focus much more on ventilation strategy and make sure patients’ lungs don’t take any further damage from mechanical ventilation. The hardest choice has been when to give up, as patients died waiting for ICU beds. This has been the toughest period in my whole life. We should mobilize resources in the early stage of the outbreak, mobilize ICUs and mobilize medical beds.
PROGNOSIS AND RECOVERY
19. Does Covid-19 inflict permanent damage to patients’ health?
We don’t know. Some patients have been discharged with lingering symptoms like difficulty breathing, but we need more time to follow-up and see how much they’ve improved.
PROTECTING HEALTHCARE WORKERS
20. What are your lessons learned on the optimal and practical PPE needs for the health care providers in the ICU? In particular, should we assume full airborne precautions, or is droplet precaution sufficient?
If possible, I recommend airborne protection. Because we're not sure whether the ICU environment is okay or not. Not all ICUs are negative pressurized. So if possible, I recommend airborne protection. When doing procedure, especially intubation, the more protection the better. We need to wear N95 respirator, full-hooded plus an additional gown outside to protect any water or secretions from the patients. It is very important to protect our medical personnel.
21. There is a high infection rate among medical professionals, how to protect them?
Hospital acquired infection is often at the beginning, due to limited personal protective equipment (PPE) supply. So we control the consumption of PPEs, and healthcare workers are allowed to leave ICU for meal or restroom for only once a day, before PPE supply goes back to normal.
22. How did health care workers recycle or disinfected PPE even if they are intended for one-time use?
Most of the PPE are disposable. We only recycle the goggles, which can be disinfected with alcohol.
23. What is the optimal number of times to don and doff PPE for the ICU nurses and physicians?
We work in ICU with PPE and eye-shield for 4 hours and change shift with next shift.
24. What is the optimal shift rotation, in terms of number of hours, for nurses and physicians in the ICU?
Regarding shift rotation for physicians - In my ICU, we assign 3 ICU physicians for each 12-hour shift. In the first 4 hours, all 3 doctors stay in the ICU to make sure they know everything about the patients and to follow the treatment. After 4 hours, only one physician will stay in the ICU. The other 2 physicians will take a rest in the living area. They can change shift with each other. This is for the 12-hour shift. And they have flexibility in deciding their schedules. For example, whoever will stay in ICU for one or two hours first, and the other 2 can rest in the living area. This is our shift schedule for physicians.
For the nurses, we assign a group of nurses for every 8-hour shift. One nurse takes care of 2 patients. The nurses will also exchange with each other during the 8-hour shift in order to have lunch, restroom breaks, or to have a nap.
25. What is the rate of infection of healthcare workers in ICU as more experience with the disease has evolved? Overall, what percent of the healthcare workers became positive for the virus?
In my department, 2 nurses got infected in the hospital at the early stage of the outbreak. Right now, we have one more nurse who is infected but is without any symptoms. She has now been quarantined for 14 days and we will follow up for one month. In my department, we have about 170 medical personnel including physicians and nurses. We have no physicians infected with COVID-19.
The total number of medical staff infected with COVID in my hospital is around 100. Total number of medical staff in my hospital is around 3000. With that you can calculate the percentage. Most of these infections happened during the early stage of the outbreak, because we did not know that the virus could transmit so quickly and also we did not have enough PPEs. But right now we are doing okay. I think we are almost done with infection in medical staff. I have the impression that we have not got any new cases since early March.
VACCINES AND CURES
26. Have you used traditional Chinese medicine to treat patients? Is it possible to avoid herbal and drug interactions?
In ICUs, we never use traditional Chinese medicine or herbs with our patients.
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