High-flow nasal cannula oxygen therapy in patients undergoing thoracic surgery: current evidence and practice

Determining the optimum high-flow nasal cannula flow rate to achieve the desired fraction of inspired oxygen: A bench study

BACKGROUND

Purpose: High-flow nasal cannula (HFNC) has many benefits in various clinical conditions. The original hypothesis suggests that the high and constant fraction of inspired oxygen (FiO2) is one of the main physiological effects. However, increasing evidence shows that there is a gap between the actual FiO2 and administered FiO2. We aimed to determine the actual FiO2 under different respiratory conditions and develop a regression model using a spontaneous breathing lung model.

METHODS

A spontaneous breathing simulation model was built using an airway manikin and a model lung. The FiO2 was measured under different respiratory conditions with varying tidal volumes and respiratory and HFNC flow rates. The relationships between the respiratory parameters and actual FiO2 were determined and used to build the predictive model.

RESULTS

The actual FiO2 was negatively correlated with respiratory rate and tidal volume and positively correlated with HFNC flow. The regression model could not be developed using simple respiratory parameters. Therefore, we introduced a new variable, defined as flow ratio, which equaled the HFNC flow divided by inspiratory flow. Our equation demonstrated that the actual FiO2 was mainly determined by the flow ratio in a non-linear relationship. Accordingly, a flow ratio greater than 1 did not ensure a constant high FiO2, whereas a flow ratio >1.435 could produce FiO2 >0.9.

CONCLUSION

The FiO2 during HFNC was not constant even at sufficiently high oxygen flow compared with inspiratory flow. The predictive model showed that the actual FiO2 was mainly determined by the flow ratio.

Non-intubated tracheal resection and reconstruction for a tracheal tumor in an 8-year-old child

INTRODUCTION

It has been reported that non-intubated anesthesia can be used successfully in adult trachea reconstruction. Herein, our center reported a case of a child undergoing non-intubated trachea reconstruction for benign tracheal tumors.

CASE DESCRIPTION

In January 2023, it was decided to attempt tracheal resection and reconstruction (TRR) in an 8-year-old child with an inflammatory myofibroblastic tumor under non-intubated spontaneous breathing. After anesthesia induction, the laryngeal mask airway (LMA) was inserted. Thereafter, a bilateral superficial cervical plexus block was performed with 15 mL of 0.25% ropivacaine injected into each side. The patient was induced to resume spontaneous breathing by artificially assisted ventilation with an oxygen flow of 2 to 5 L/min and FiO2=1. After tracheotomy, the oxygen flow was increased to 15 L/min to improve the local oxygen flow to maintain the pulse oxygen saturation (SpO2) above 90% under spontaneous breathing. The patient had stable spontaneous breathing after tracheal anastomosis. The anastomosis was perfect without leakage. The LMA was removed and oxygen was given by the nasal catheter under light sedation at post anesthesia care unit (PACU).

CONCLUSION

Tracheal reconstruction under spontaneous breathing may be an alternative anesthesia method for upper tracheal surgery in children.

Intraoperative high flow oxygen therapy for tubeless anaesthesia in thoracoscopic surgery

Tubeless anaesthesia has become widespread in videothoracoscopic surgery, even in major procedures such as lobectomies. There are several advantages in avoiding general anaesthesia and one-lung mechanical ventilation, such as faster recovery and shorter hospital stays. However, hypoxaemia and hypercapnia are the most reported causes of conversion to general anaesthesia. High Flow Oxygen Therapy (HFOT) generates flow-dependent positive end-expiratory pressure, improves oxygenation and also carbon dioxide washout by flow-dependent dead space flushing. For this reason, intraoperative HFOT may reduce the rate of conversion to general anaesthesia. We report our experience with intraoperative HFOT in a 71-year-old female with lung adenocarcinoma undergoing VATS upper left lobectomy.

Effects of high flow nasal cannula following minimally invasive esophagectomy in ICU patients: A prospective pre-post study

BACKGROUND/PURPOSE

Patients with esophageal cancer who undergo minimally invasive esophagectomy are at risk of postoperative pulmonary complications. High-flow nasal cannula oxygen therapy delivers humidified, warmed positive airway pressure but has not been applied routinely after surgery. Here, we aimed to compare high-flow nasal cannula and conventional oxygen therapy in patients with esophageal cancer during intensive care unit hospitalization 48 h postoperatively.

METHODS

In this prospective pre- and post-intervention study, patients with esophageal cancer who underwent elective minimally invasive esophagectomy (MIE) and were extubated in the operation room and admitted to the intensive care unit postoperatively were assigned to receive either high-flow nasal cannula (HFNCO) or standard oxygen (SO) therapy. Participants in the SO group were recruited before January 2020, and those in the HFNCO group were enrolled after January 2020. The primary outcome was the difference in postoperative pulmonary complication incidence. Secondary outcomes were the occurrence of desaturation within 48 h, PaO2/FiO2 within 48 h, anastomotic leakage, length of intensive care unit and hospital stay, and mortality.

RESULTS

The standard oxygen and high-flow nasal cannula oxygen groups comprised 33 and 36 patients, respectively. Baseline characteristics were comparable between groups. In the HFNCO group, postoperative pulmonary complication incidence was significantly reduced (22.2% vs 45.5%) and PaO2/FiO2 was significantly increased. No other between-group differences were observed.

CONCLUSION

HFNCO therapy significantly reduced postoperative pulmonary complication incidence after elective MIE in patients with esophageal cancer without increasing the risk of anastomotic leakage.

[The perioperative role of high-flow cannula oxygen (HFNO)]

High-flow nasal cannula oxygen (HFNO) is commonly used during the perioperative period. Its numerous physiological benefits, satisfactory tolerance and ease of use have led to its widespread application in intensive care and post-anesthesia care units. HFNO is also used in the operating theater in multiple indications: as oxygen supplementation (associated with pressurization) prior to orotracheal intubation; in digestive and bronchial endoscopies, especially in patients at risk of hypoxemia; and in intraoperative surgery requiring spontaneous ventilation (ENT, thoracic surgery…). During the postoperative period, HFNO can be used in a curative strategy for respiratory failure or in a prophylactic strategy to prevent reintubation. In a curative approach, HFNO seems of interest following cardiac or thoracic surgery but has not been evaluated in respiratory failure subsequent to abdominal surgery, in which case noninvasive ventilation remains the gold standard. The risk of respiratory complications depends on type of surgery and on patient comorbidities. As prophylaxis, HFNO is currently preferred to conventional oxygen therapy after cardiac or thoracic surgery, especially in patients at high risk of respiratory complications. For the clinician, it is important to acknowledge the limits of HFNO and to closely monitor patients receiving HFNO, the objective being to avoid delays in intubation that could lead to increased mortality.

[Anaesthetic Management of Non-intubated Video-assisted Thoracic Surgery]

Non-intubated thoracic surgery is currently gaining popularity. In select patients and in experienced centres, non-intubated approaches may enable patients to safely undergo thoracic surgical procedures, who would otherwise be considered at high risk from general anaesthesia. While non-intubated techniques have been widely adopted for minor surgical procedures, its role in major thoracic surgery is a topic of controversial debate.This article discusses disadvantages of intubated anaesthetic approaches and advantages of non-intubated thoracic surgery as well as the anaesthetic management. This includes surgical and anaesthetic criteria for patient selection, suitable regional anaesthetic techniques, concepts for sedation and maintenance of airway patency as well as the management of perioperative complications.Non-intubated thoracic surgery has the potential to reduce postoperative morbidity and hospital length of stay. Successful non-intubated management depends on a standardised and well-trained interdisciplinary approach, especially regarding patient selection and perioperative complications.

Comparison of High-Flow Humidified Oxygen With Conventional Continuous Positive Airway Pressure in Nonventilated Lungs During Thoracic Surgery: A Randomized Cross-Over Study

OBJECTIVE

This study assessed the efficacy of high-flow humidified oxygen (HFHO) as an alternative to continuous positive airway pressure (CPAP) for improving oxygenation while preserving nonventilated lung collapse during one-lung ventilation.

DESIGN

A prospective randomized cross-over trial.

SETTING

A tertiary medical center.

PARTICIPANTS

The study comprised 28 patients undergoing elective thoracotomy with one-lung ventilation using a double-lumen endobronchial tube placement.

INTERVENTIONS

The patients received prophylactic CPAP or HFHO to the nonventilated lung for 20 minutes and were then crossedover to the other oxygenation modality for 20 minutes, with a 20-minute recovery interval between the two modalities.

MEASUREMENTS AND MAIN RESULTS

Changes in respiratory parameters and lung deflation quality were recorded. Both CPAP and HFHO increased the partial pressure of arterial oxygen in either sequence in both groups, ranging from 31.8-to-66.0 mmHg. However, the increments from these two interventions were not statistically significant (95% confidence interval -12.84 to 21.87; p = 0.597). There were no differences in other parameters. Half the patients receiving CPAP experienced worsening of the surgical condition, whereas the HFHO patients experienced no change or reported a better lung deflation (p < 0.001).

CONCLUSION

HFHO could be an alternative method to CPAP for improving arterial oxygenation while preserving lung deflation during one-lung ventilation. However, additional studies are warranted in regard to its cost-effectiveness and establishment as a routine treatment.

High flow nasal cannula versus conventional oxygen therapy in postoperative patients at high risk for pulmonary complications: A systematic review and meta-analysis

BACKGROUND

The effects of high flow nasal cannula (HFNC) on postoperative patients at high risk for pulmonary complications(PC) are controversial. We aimed to further determine the effectiveness of HFNC in postoperative patients at high risk for PC by comparison to conventional oxygen therapy (COT).

METHODS

We performed a comprehensive search that compared HFNC with COT in postoperative patients at high risk for PC. The main outcomes were length of hospital stay (hospital LOS) and respiratory complications.

RESULTS

Six trials with a total of 733 patients were pooled in our final studies. Except for Hospital LOS (I²  = 53%, χ²  = 8.51, P = .07) and rate of intubation or non-invasive ventilation (NIV) for respiratory failure (RF) (I²  = 49%, χ²  = 1.97, P = .16) between HFNC and COT, no significant heterogeneity was found in outcome measures. Compared with COT, HFNC was associated with a lower rate of intubation or NIV for RF (RR 0.23, 95% CI 0.08-0.66, P = .006) and rate of hypercapnia (RR 0.37, 95% CI 0.20-0.68, P = .002). As for the Hospital LOS, ICU LOS, rate of requirement of O2 after discontinuous and hypoxemia, HFNC did not show any advantage over COT. Trial Sequential Analysis (TSA) for Hospital LOS showed that monitoring boundaries were finally not surpassed and required information size (RIS) was not met.

CONCLUSIONS

The available randomised controlled trials (RCTs) suggest that, among the postoperative patients at high risk for PC, HFNC therapy compared with the COT significantly reduces rate of incubation or NIV for RF and rate of hypercapnia, meanwhile is safely administered. Further large-scale, multicenter, randomised and controlled studies are needed to confirm our results.

Prevent deterioration and long-term ventilation: intensive care following thoracic surgery

PURPOSE OF REVIEW

Patients with indication for lung surgery besides the pulmonary pathology often suffer from independent comorbidities affecting several other organ systems. Preventing patients from harmful complications due to decompensation of underlying organ insufficiencies perioperatively is pivotal. This review draws attention to the peri- and postoperative responsibility of the anaesthetist and intensivist to prevent patients undergoing lung surgery deterioration.

RECENT FINDINGS

During the last decades we had to accept that 'traditional' intensive care medicine implying deep sedation, controlled ventilation, liberal fluid therapy, and broad-spectrum antimicrobial therapy because of several side-effects resulted in prolongation of hospital length of stay and a decline in quality of life. Modern therapy therefore should focus on the convalescence of the patient and earliest possible reintegration in the 'life-before.' Avoidance of sedative and anticholinergic drugs, early extubation, prophylactic noninvasive ventilation and high-flow nasal oxygen therapy, early mobilization, well-adjusted fluid balance and reasonable use of antibiotics are the keystones of success.

SUMMARY

A perioperative interprofessional approach and a change in paradigms are the prerequisites to improve outcome and provide treatment for elder and comorbid patients with an indication for thoracic surgery.

Humidified versus nonhumidified low-flow oxygen therapy in children with Pierre-Robin syndrome: Study protocol for a randomised controlled trial

AIMS AND OBJECTIVES

To evaluate the necessity of oxygen humidification for low-flow oxygen therapy in children with Pierre-Robin syndrome.

BACKGROUND

Whether to carry out humidification or not in the low-flow oxygen delivery remains unclear, and currently, there is no published study on this issue in the population of children. Therefore, it is necessary to conduct more studies to elucidate this issue.

DESIGN

A randomised controlled trial.

METHODS

We attempt to report this randomised controlled trial to comply with the Standard Protocol Items: Recommendations for Interventional Trials (SPIRIT). 188 children with Pierre-Robin syndrome will be expected to inclusion. The participants will be randomly divided into the humidified group (n = 94) and nonhumidified group (n = 94) at a ratio of 1:1. For humidified group, the oxygen will be routinely humidified with disposable bottle containing sterile water, whereas for nonhumidified group, the oxygen will not be humidified. Average arterial oxygen partial pressure (PaO₂ ) and carbon dioxide partial pressure (PaCO₂ ), incidence of ventilator-associated pneumonia (VAP), nasal cavity dryness, nasal mucosal bleeding and bacterial contamination of the humidified bottle, the cost of nasal oxygen therapy and duration of ICU stay are collected and analysed.

RESULTS

The study is planned to start in May 2019, and the results will be expected in July 2020.

CONCLUSIONS

This study is expected to provide a credible evidence on the necessity of routine oxygen humidification in low-flow oxygen delivery.

RELEVANCE TO CLINICAL PRACTICE

Understanding the role of oxygen humidification and no humidification for low-flow oxygen therapy in the population of children is beneficial to the nursing care of healthcare providers in clinical setting.

Early nasal high-flow versus Venturi mask oxygen therapy after lung resection: a randomized trial

Background

Data on high-flow nasal oxygen after thoracic surgery are limited and confined to the comparison with low-flow oxygen. Different from low-flow oxygen, Venturi masks provide higher gas flow at a predetermined fraction of inspired oxygen (FiO₂). We conducted a randomized trial to determine whether preemptive high-flow nasal oxygen reduces the incidence of postoperative hypoxemia after lung resection, as compared to Venturi mask oxygen therapy.

Methods

In this single-center, randomized trial conducted in a teaching hospital in Italy, consecutive adult patients undergoing thoracotomic lung resection, who were not on long-term oxygen therapy, were randomly assigned to receive high-flow nasal or Venturi mask oxygen after extubation continuously for two postoperative days. The primary outcome was the incidence of postoperative hypoxemia (i.e., ratio of the partial pressure of arterial oxygen to FiO₂ (PaO₂/FiO₂) lower than 300 mmHg) within four postoperative days.

Results

Between September 2015 and April 2018, 96 patients were enrolled; 95 patients were analyzed (47 in high-flow group and 48 in Venturi mask group). In both groups, 38 patients (81% in the high-flow group and 79% in the Venturi mask group) developed postoperative hypoxemia, with an unadjusted odds ratio (OR) for the high-flow group of 1.11 [95% confidence interval (CI) 0.41–3] (p = 0.84). No inter-group differences were found in the degree of dyspnea nor in the proportion of patients needing oxygen therapy after treatment discontinuation (OR 1.34 [95% CI 0.60–3]), experiencing pulmonary complications (OR 1.29 [95% CI 0.51–3.25]) or requiring ventilatory support (OR 0.67 [95% CI 0.11–4.18]). Post hoc analyses revealed that PaO₂/FiO₂ during the study was not different between groups (p = 0.92), but patients receiving high-flow nasal oxygen had lower arterial pressure of carbon dioxide, with a mean inter-group difference of 2 mmHg [95% CI 0.5–3.4] (p = 0.009), and were burdened by a lower risk of postoperative hypercapnia (adjusted OR 0.18 [95% CI 0.06–0.54], p = 0.002).

Conclusions

When compared to Venturi mask after thoracotomic lung resection, preemptive high-flow nasal oxygen did not reduce the incidence of postoperative hypoxemia nor improved other analyzed outcomes. Further adequately powered investigations in this setting are warranted to establish whether high-flow nasal oxygen may yield clinical benefit on carbon dioxide clearance.

Trial registration

ClinicalTrials.gov, NCT02544477. Registered 9 September 2015.

Electronic supplementary material

The online version of this article (10.1186/s13054-019-2361-5) contains supplementary material, which is available to authorized users.