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In our first webinar series, five international experts discussed various aspects of treating patients with high flow nasal cannula therapy (HFNC) (
Sharon Einav and Tommaso Mauri.
Before initiating HFNC therapy, we need to identify the patient’s criteria and adapt treatment based on clinical guidelines. This webinar looked at the different types of patients and how they can benefit from this therapy.
Tommaso Mauri and Jens Bräunlich.
In order to improve physiology and outcomes of patients supported by HFNC, it is crucial to adjust the flow rate, FiO2, temperature, and cannula size based on target physiological variables such as respiratory effort, ROX index, respiratory rate, etc., as well as on patient comfort. We focused on how to optimize HFNC this physiology-based approach.
Oriol Roca and Sharon Einav.
To better understand the progress of nasal high flow nasal cannula therapy it is essential to monitor the patient's respiratory parameters such as oxygenation and RR. In this session, we covered different aspects of respiratory monitoring and explain how they could be used at the bedside.
Jean-Damien Ricard and Tommaso Mauri.
The point in time at which a critically ill patient is intubated can play an important role in their survival, especially in those with hypoxemic respiratory failure. In this webinar, we talked about when to intubate patients undergoing HFNC therapy and which parameters should be taken into consideration.
Jens Bräunlich and Tommaso Mauri.
The latest studies indicate that HFNC may have beneficial effects on patients with hypercapnia. In this webinar, we reviewed the effects this therapy may have on these patients and how to approach their treatment.
Jean-Damien Ricard and Oriol Roca.
The COVID-19 pandemic has seen HFNC therapy become more and more relevant in various departments, including emergency care, pediatrics, and general patient wards. In this webinar, we looked at where this therapy could be initiated to achieve better patient outcomes.
There is currently no known protocol for congenital heart surgery
There is no formal protocol for weaning. (See the next webinar on February 24 about optimizing HFOT settings).
Data is clear on the benefit of CPAP, there is not enough literature on HFNO.
(a) In high risk/obese patients particularly after chest surgery and abdominal surgery. Also consider ENT if there are secretions. (b) There could be a possible issue with pressure on surgical sutures with NIV if it was gastric surgery. (c) In failed HFNO, heart failure patients. You could also alternate HFNO with NIV.
Prevention : HFNC is good for comfort and maybe shortened stays. Treatment: This is unclear (not enough patients). NIV shows benefit but there is not enough head-to-head data.
There are three papers showing the cost-effectiveness of HFNC. It is obviously not for indiscriminate use. For pediatrics, there is also literature justifying the use of HFNO for bronchiolitis:
There is also some cost-utility work on HFNO for COPD use at home which appears quite convincing:
Contraindications: Patient not awake / nobody to see/montior the patient (no alarms).
Mainly delayed intubation; possible P-SILI as well.
Not at all. The advantage of HFO is in the high flows. Hence, if there is no respiratory distress (i.e., low flows) and supplementation up to an FiO2 of 0.5-0.6 suffices, there is no need.
There are no RCTs but there are several interesting studies thus far:
This may be better than immediately intubating these patients…
Definitely yes, although the literature is still not sufficiently strong. There are no RCTs but there are several interesting studies thus far (see answer to previous question).
Yes, we use a specific connector for tracheostomy. Only in monitored areas. Not for patients who need suction more than 2 or more times each nursing shift (>twice in 8 hours).
Over COT and before NIV for all patients except heart failure.
Possibly looking forward there may be ways to identify these patients based on their aeration distributions (CT) and WOB (EiT). We are not there yet.
Helmet is the interface, not the mode of ventilation. Use of a helmet interface requires experience. We use it for patients who are cooperative and alternate it with HFNO since it limits communication and feeding.
In terms of mode, BiPAP definitely first line only for pulmonary edema (heart failure). An interesting paper on helmet vs. HFNO for heart failure (single center about 200 patients):
For COVID: 110 patients:
Among patients with COVID-19 and moderate to severe hypoxemia, treatment with helmet noninvasive ventilation, compared with high-flow nasal oxygen, resulted in no significant difference in the number of days free of respiratory support within 28 days.
We alternate based on the patients tolerance and response.
BiPAP definitely.
The problem is that mean apnea times in the studies for the metaanalysis were <2 minutes and even <1 in critical care patients. Also, most patients included in these studies were not with severe hypoxia, no data on difficult intubations, not enough on obesity (one study) and not on preganacy. So overall I agree with your clinical impression and we use it during intubations of patients with hypoxemia in our ICU.
There may be P-SILI with HFNO as well but this is vey diffucult to measure clinically. There is direct evidence of this in only neonatal cases with baro/volutrauma but we must assume the possibility exists in adults too.
At least 30 liters per minute. (See the upcoming webinar on optimizing HFOT settings on February 24.)
Weaning from HFNC should be gradual as this is a potent non invasive support. FiO2 could be the first setting to decrease, while flow can be safely reduced after FiO2 becomes <50%. When FiO2 is <40% with flow <40 l/min, transition to standard oxygen, for example to discharge the patient from the ICU. This could be attempted with 2 hours of close monitoring.
See above.
The paper mentioned in my talk by Pinkham et al. is very recent and confirms values between 2 and 5 cmH2O (
I would be careful, for the study in Crit Care 2020 on flows > 60 l/min we used 2 humidifiers.
See above.
We do use HFNC with NGT, usually smaller cannula, being careful of accurate positioning and checking from time to time.
Aerosol shouldn't be an issue, HFNC can even grant improved delivery to the distal airways, see
Yes, if the high flow is connected to a mask you just give a lot of oxygen, probably lose both PEEP effect (no occlusion of the nares) and CO2 washout (no direct flow in the upper airways), I would avoid that.
No, CO2 clearance is not affected as long as there is a circulation of gas, open mouth and venturi effect may reduce tha alveolar FiO2 and the PEEP effect, determining worsening oxygenation.
We normally use EIT by continuous monitoring of end-expiratory impedance before and after start of HFNC.
OSI is the oxygenation saturation index. Is is normally defined as [Fio2 × mean airway pressure × 100)/oxygen saturation by pulse oximetry (Spo2)] and predicts outcomes of mechanically ventilated patients. In the case of HFNC patients, MAP may be estimated by the level of flow delivered, but no data is available about its utility.
There is probably no single variable that reflects the response to the treatment. I think that different things happen when the patient is doing well: oxygenation improvement, decrease in respiratory rate, relief in dyspnea feeling… Regarding the right flow, we know that most of the effects are flow-dependent and, therefore, when we start the treatment in paitents with acute hypoxemic respiratory failure, we try to use the highest tolerated flow. However, we can't start with 60Lpm as the patient does not tolerate it. So we start with 40Lpm and once the patient is used to receiving this amount of flow, we can progressively increase up to 60Lpm. This increase can usually be made in the first 30 minutes of treatment.
(Editor's note: "aspects" has been understood as "variables" for the purposes of this answer) Clinical examination, respiratory rate, use of accessory muscles, thoraco-abdominal asynchrony, SpO2, FiO2
There is no specific timeframe for expected improvement. However, it is true that some thresholds of different variables have been described as predictors of HFNC failure at different time-points.
The use of accessory muscles suggests that the inspiratory effort is excessive. Similarly, low PaCO2 or a negative swing in CVP could also suggest the same. (Please also see the second webinar for an answer to this question.)
I do not wait. If the patient is not responding to the treatment, I try to increase the flow up to the maximum tolerated. And if the patient is still not responding, one would need to escalate the treatment.
The evidence is sometimes controversial because the criteria for intubation may vary a lot between different countries, hospitals or even doctors in the same ICU. Thus, some studies compared early versus delayed intubation taking the time of ICU admission as moment 0. The majority of them have shown that earlier intubation is associated with better outcomes. In other words, delayed intubation may be associated with increased mortality.
My suggestion would be not to base the decision of intubating a patient based only on a number. The clinical examination of the patient is extremely important. The ROX may help you to decide if the patient is doing well or not, as you can repeat the measurement several times. The benefit of the ROX is that it is based on physiological variables that determine the outcome (need for intubation). We proposed an algorithm that may help in a review in ICM with Jean-Damien Ricard in 2020 that we are now testing in a RCT.
In our clinical practice we rarely do it. There is a good correlation between SpO2 and PaO2 if you keep the SpO2 < 98%.
These patients usually need lower flows and benefit more from active humidification that improves secretion clearance. But I would base my decisions in the same way as for HFNC patients.
As commented before, I would never make a decision based on just a number. I think that the ROX value should be combined with the clinical examination of the patient.
Many observational studies have suggested that NHF prevents intubation. The clinical impression was unequivocally demonstrated in a large randomized trial (
Of note, the data is less conclusive in patients with hematological or oncological disorders.
If the question is interpreted as "Is it reasonable to start NHF and perhaps escalate to invasive ventilation in a patient beyond 65 years", the answer is yes, but patients and family must be informed that the prognosis is much less favorable than in younger patients. My bias is that intubation should be discussed on an individual basis above 70-75, depending on the presence of comorbodities and the fitness of the patient before being infected by Covid.
Yes, for at least two reasons. First, although there is - at a cohort level - a relationship between the importance of lung involvement and outcome, on an individual basis, we have sometimes had very rapid recovery despite an initial unfavorable radiological assessment. Second, the radiological phenotype also plays a role (we had the impression that very diffuse ground glass was less "bad" than consolidation display). And finally, even if the patient is at high risk of intubation, NHF can be initiated and will help preoxygenate the patient, and will serve as apneic oxygenation during laryngoscopy.
I don't yet have any personal experience with 100 l/min. My bias is that because there is a linear relationship between flow and both positive pressure and deadspace washout, this suggests that beneficial effects of NHF are more important at 100 l/min than at 60. Obviously, the question of tolerance is a key issue. We need more data on the tolerance of these very high flows.
This is a vast question and whole consensus conferences have been dedicated to this unique question. Bear in mind several facts: 1) there is no 100%-sure test or group of parameters that predict safe extubation; 2) reintubation will occur in 10%-20% of patients; 3) unplanned extubation does not systematically lead to reintubation (only 40% approx.). That means we as clinicians must stay very humble as to our capacity to predict extubation outcome. Always perform either a T-piece trial or minimal pressure support spontaneous breathing trial. When to start these trials? Partial or complete resolution of the cause that led to intubation. Hemodynamic stability without vasopressors, FiO2 < 40%, PEEP < 5, no or little neurological and cognitive impairment, appropriate cough, no or little muscle weakness.
There could be two possible reasons: 1. It could be an optimized ventilation and endobronchial humidity, which leads to reduced triggering of an ECOPD 2. Prevention of symptoms worsening in the case of exacerbation onset.
After some more clinical studies about efficiency this could be the next step to optimize NHF therapy.
We have the same experience.
In my ICU, we performed nasal high flow in Covid-19 patients throughout all the consecutive surges in rooms without negative pressure without experiencing staff contamination. So the answer, in my opinion, is yes, nasal high flow can be performed in a room without negative pressure, provided staff is properly equipped with PPE.
(Editor's note: This question was interpreted as "What safety parameters should be observed when using HFOT outside of the ICU?"). Tthere is no definite answer to that question, because it depends on how far from the ICU nasal high flow is performed, how well the staff is trained to perform and monitor nasal high flow in patients with acute respiratory failure, if these patients will have continuous measurment of SpO2 or not, etc. Having said this, I believe FiO2 should be limited, and not exceed 60%; SpO2 should not be below 92-94% ; respiratory rate no greater than 25-28. if patients are out of one of these targets, then an ICU physician should be called to assess these patients
I have no personal data or experience. My bias is that if there is no possiblity of electric supply, then it will be problematic to not have any humidification. If an external battery was available and it covered the entire flight time, then I would see no "technical" reasons why such a device could not be operated during a helictopter flight (Editor's note: To our knowledge, there is currently no humidification device available that is approved for transport.)
The Rox index was established and validated in adult (over 18 yo) patients with pneumonia-related acute hypoxemic respiratory failure. It makes sense to apply it to younger patients whose physiological characteristics are similar to those of adult patients. I'm aware of at least one publication in which the Rox score was established in a pediatric population:
Several studies have shown that use of nasal high flow reduced the intubation rate in children admitted for respiratory failure due to bronchiolitis:
There is no similar data in adults, most probably because the clinical entity of bronchiolitis in adults is less defined and hence much less frequent.
The contents of this page are for informational purposes only and are not intended to be a substitute for professional training or for standard treatment guidelines in your facility. The responses to the questions on this page were prepared by the respective webinar's speaker; any recommendations made here with respect to clinical practice or the use of specific products, technology, or therapies represent the personal opinion of the speaker only, and may not be considered as official recommendations made by Hamilton Medical AG. Hamilton Medical AG provides no warranty with respect to the information contained ion this page and reliance on any part of this information is solely at your own risk.