Adjunct and rescue therapies for refractory hypoxemia: prone position, inhaled nitric oxide, high frequency oscillation, extra corporeal life support

Initiation of Inhaled Nitric Oxide by Air Transport Team in Adult COVID-19 Respiratory Failure

The coronavirus disease 2019 (COVID-19) pandemic has caused a significant increase in the volume of critical care flight transports between outlying referral hospitals and tertiary care facilities. Because of the tropism of severe acute respiratory syndrome coronavirus 2, flight crews are often asked to transport mechanically ventilated patients in refractory hypoxemic respiratory failure. The authors present a case series of 5 patients with COVID-19 acute respiratory distress syndrome (ARDS) who were initiated on inhaled nitric oxide (iNO) by the transport team before rotor wing transport and survived the journey in stable or improved condition upon arrival. Previously, no case reports have described adults with COVID-19 ARDS transported after iNO initiation by the transport team. This case series shows the feasibility of iNO initiation by trained air medical transport teams and suggests a short-term stabilizing effect of iNO in patients with ARDS from COVID-19.

Inhaled nitric oxide reduces the intrapulmonary shunt to ameliorate severe hypoxemia after acute type A aortic dissection surgery

BACKGROUND

To assess the relationship between the intrapulmonary shunt and PaO₂/FiO₂ in severe hypoxemic patients after acute type A aortic dissection (ATAAD) surgery and to evaluate the effect of inhaled nitric oxide (iNO) on intrapulmonary shunt.

METHODS

Postoperative ATAAD patients with PaO₂/FiO₂ ≤ 150 mmHg were enrolled. Intrapulmonary shunt was calculated from oxygen content of different sites (artery [CaO₂], mixed venous [CvO₂], and alveolar capillary [CcO₂]) using the Fick equation, where intrapulmonary shunt = (CcO₂-CaO₂)/(CcO₂-CvO₂). Related variables were measured at baseline (positive end expiratory pressure [PEEP] 5 cm H₂O), 30 min after increasing PEEP (PEEP 10 cm H₂O), 30 min after 5 ppm iNO therapy (PEEP 10 cm H₂O + iNO), and 30 min after decreasing PEEP (PEEP 5 cm H₂O + iNO).

RESULTS

A total of 20 patients were enrolled between April 2019 and December 2019. Intrapulmonary shunt and PaO₂/FiO₂ were correlated in severe hypoxemic, postoperative ATAAD patients (adjusted R² = 0.467, p < 0.001). A mixed model for repeated measures revealed that iNO, rather than increasing PEEP, significantly decreased the intrapulmonary shunt (by 15% at a PEEP of 5 cm H₂O and 16% at a PEEP of 10 cm H₂O, p < 0.001 each) and increased PaO₂/FiO₂ (by 63% at a PEEP of 5 cm H₂O and 65% at a PEEP of 10 cm H₂O, p < 0.001 each). After iNO therapy, the decrement of intrapulmonary shunt and the increment of PaO₂/FiO₂ were also correlated (adjusted R² = 0.375, p < 0.001).

CONCLUSIONS

This study showed that intrapulmonary shunt and PaO₂/FiO₂ were correlated in severe hypoxemic, postoperative ATAAD patients. Furthermore, iNO, rather than increasing PEEP, significantly decreased the intrapulmonary shunt to improve severe hypoxemic conditions.

Patterns of Use of Adjunctive Therapies in Patients With Early Moderate to Severe ARDS: Insights From the LUNG SAFE Study

BACKGROUND

Adjunctive strategies are an important part of the management of ARDS. However, their application in clinical practice remains inconsistent.

RESEARCH QUESTION

We wished to determine the frequency and patterns of use of adjunctive strategies in patients with moderate to severe ARDS (Pao₂/Fio₂ [P/F ratio] < 150) enrolled into the Large observational study to UNderstand the Global impact of Severe Acute respiratory FailurE (LUNG SAFE) study.

STUDY DESIGN AND METHODS

The LUNG SAFE study was an international, multicenter, prospective cohort study of patients with severe respiratory failure, conducted in 2014 in 459 ICUs from 50 countries. The primary objective of this substudy was to determine the frequency of use of widely available (neuromuscular blockade, prone position) adjuncts vs adjuncts requiring specialized equipment (extracorporeal membrane oxygenation, inhaled vasodilators, high-frequency ventilation) in patients in the first 48 h of moderate to severe ARDS (P/F ratio < 150).

RESULTS

Of 1,146 patients on invasive ventilation with moderate to severe ARDS, 811 patients (71%) received no adjunct within 48 h of ARDS onset. Of 335 (29%) that received adjunctive strategies, 252 (75%) received a single strategy, and 83 (25%) receiving more than one adjunct. Of ARDS nonsurvivors, 67% did not receive any adjunctive strategy in the first 48 h. Most patients (67%) receiving specialized adjuncts did not receive prone positioning or neuromuscular blockade. Patients that received adjuncts were more likely to have their ARDS recognized, be younger and sicker, have pneumonia, be more difficult to ventilate, and be in a European high-income country than those that did not receive adjuncts.

INTERPRETATION

Three in 10 patients with moderate to severe ARDS, and only one-third of nonsurvivors, received adjunctive strategies over the first 48 h of ARDS. A more consistent and evidence-driven approach to adjunct use may reduce costs and improve outcomes in patients with moderate to severe ARDS.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT02010073; URL: www.clinicaltrials.gov.

COVID-19 Diagnostic and Management Protocol for Pediatric Patients

This review aims to verify the main epidemiologic, clinical, laboratory-related, and therapeutic aspects of coronavirus disease 2019 (COVID-19) in critically ill pediatric patients. An extensive review of the medical literature on COVID-19 was performed, mainly focusing on the critical care of pediatric patients, considering expert opinions and recent reports related to this new disease. Experts from a large Brazilian public university analyzed all recently published material to produce a report aiming to standardize the care of critically ill children and adolescents. The report emphasizes on the clinical presentations of the disease and ventilatory support in pediatric patients with COVID-19. It establishes a flowchart to guide health practitioners on triaging critical cases. COVID-19 is essentially an unknown clinical condition for the majority of pediatric intensive care professionals. Guidelines developed by experts can help all practitioners standardize their attitudes and improve the treatment of COVID-19.

Initial clinical impact of inhaled nitric oxide therapy for refractory hypoxemia following type A acute aortic dissection surgery

BACKGROUND

To evaluate the effect of inhaled nitric oxide (iNO) therapy on oxygenation and clinical outcomes in patients with refractory hypoxemia after surgical reconstruction for acute type A aortic dissection (TAAD).

METHODS

A before-and-after interventional study was conducted in patients with refractory hypoxemia after surgical reconstruction for TAAD. Postoperative refractory hypoxemia was defined as a persistent PaO₂/FiO₂ ratio ≤100 mmHg despite conventional therapy. From January to November 2016, conventional treatment was carried out for refractory hypoxemia. From December 2016 to October 2017, on the basis of conventional therapy, we explored the use of iNO to treat refractory hypoxemia.

RESULTS

Fifty-three TAAD patients with refractory hypoxemia were enrolled in this study. Twenty-seven patients received conventional treatment (conventional group), while the remaining 26 patients received iNO therapy. The PaO₂/FiO₂ ratio was significantly higher in the iNO group after treatment than in the conventional group when analyzed over the entire 72 hours. The duration of invasive mechanical ventilation was significantly reduced in the iNO group (69.19 vs. 104.56 hours; P=0.003). Other outcomes, such as mortality (3.85% vs. 7.41%, P=1.000), intensive care unit (ICU) duration (9.88 vs. 12.36 days, P=0.059) and hospital stay (16.88 vs. 20.76 days, P=0.060), were not significantly different between the two groups.

CONCLUSIONS

iNO therapy might play an ameliorative role in patients with refractory hypoxemia after surgical reconstruction for TAAD. This therapy may lead to sustained improvement in oxygenation and reduce the duration of invasive mechanical ventilation.

Prone position and extracorporeal membrane oxygenation in acute respiratory distress syndrome

Abstract Introduction: The acute respiratory distress syndrome is an inflammatory process originated by some pulmonary diseases, resulting in non-hydrostatic protein edema of the pulmonary parenchyma. The loss of the lung ability to eliminate carbon dioxide generates complications such as refractory hypoxemia, decreased alveolar dysplasia, increased complacency and hypercarbia. The treatment of acute respiratory distress syndrome, consist in measures to prevent lung diseases progression and optimize oxygenation. Objective: To identify, in the international scientific literature, cases or series of cases reporting the combined application of prone position and extracorporeal membrane oxygenation in patients with severe acute respiratory distress syndrome, as well as the benefit of these rescue therapies. Method: This is a systematic review of case reports that show the benefit of combined therapies in the treatment of patients with acute respiratory distress syndrome. Results: From the research strategy and selection criteria were included 8 studies reporting 19 cases of patients with acute respiratory distress syndrome who received the combination of the two rescue therapies. All studies showed that extracorporeal membrane oxygenation was the primary intervention. There were no reports of adverse events. Conclusion: The combinations of therapies positively interfere on the prognosis of patients with acute respiratory distress syndrome, in addition to presenting no additional risks in terms of the occurrence of adverse events; however, the prone position should precede the extracorporeal membrane oxygenation as first-line intervention. PROSPERO Registration No. CRD42018093076