Sustained Improvement In Oxygenation Research Articles

Awake Prone-Positioning in Patients on Non-Invasive Ventilation for Management of SARS-CoV-2 Pneumonia: A Systematic Review.

Patients with corona virus disease-19 (COVID-19)-induced acute hypoxemic respiratory failure (AHRF) are often on non-invasive ventilation (NIV) and use of awake prone positioning (PP) may pose concern in terms of feasibility, efficacy and side effects. This systematic review was undertaken to evaluate the feasibility and efficacy of awake PP along with NIV in them. A systematic literature search was conducted from the inception of COVID-19 until 15 August 2021. Various factors including feasibility, interface used, outcome, efficacy, side effects and limitations in both intensive care unit (ICU) and Non-ICU setups were noted. A total of 12 original articles and six case series including 359 patients were involved. Out of it, 40% (n = 122) of patients were in ICU and 60% (n = 237) in Non-ICU areas. Four clinical studies and four case series including 114 patients had evaluated PP along with helmet continuous positive airway pressure (CPAP). All had found PP with helmet CPAP to be feasible and efficacious; however, only one study documented the sustained improvement in oxygenation i.e., 12 h after PP. The present systematic review observed moderate to serious risk of bias amongst the included studies along with heterogeneity in terms of varied respiratory support amongst patients. However, the use of awake PP in patients on NIV has been found to be feasible and efficacious with no adverse events.

An Analysis of Time to Improvement in Oxygenation in Japanese Preterm and Late Preterm or Term Neonates With Hypoxic Respiratory Failure and Pulmonary Hypertension

PurposeWe analyzed data from an ongoing registry to determine time to improvement in oxygenation in preterm and late preterm or term neonates with hypoxic respiratory failure and pulmonary hypertension receiving inhaled nitric oxide (iNO) in Japan. MethodsRegistry neonates received iNO ≤7 days after birth (February 26, 2010, to October 9, 2012). Efficacy and safety profile data were collected up to 96 h after iNO initiation and, if necessary, every 24 h thereafter and before iNO discontinuation. Patients were stratified by gestational age (GA), oxygenation index (OI), and shunt direction at baseline. FindingsData were evaluated for 1106 neonates (431 with a GA <34 weeks and 675 with a GA of ≥34 weeks). Sixty percent of patients had improved OI; rates were similar for those with GAs of <34 versus ≥34 weeks (61% vs 59%). Overall, mean time to improvement was 11.4 h and tended to be shorter in the groups with a GA <34 weeks versus ≥34 weeks (9.2 vs 12.9 h). Thirty percent of responding neonates required >1 h to achieve improvement in oxygenation. Neonates with higher baseline OI had the greatest decrease in OI during the first hour of treatment. The mortality rate was higher among iNO-treated patients with a baseline OI ≥25 versus those with OI ≥15 to <25 (25% vs 12%; P = 0.0073). ImplicationsiNO treatment provided acute, sustained improvement in oxygenation in neonates with GAs <34 and ≥34 weeks; 70% of patients had improvement within 1 h, but the remaining 30% took >1 h to respond. Initiation of iNO at lower OIs was associated with reduced mortality compared with higher OI.

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

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). 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. 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. 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.

Role of Inhaled Nitric Oxide in the Management of Severe Acute Respiratory Distress Syndrome.

To date, there have been several systematic reviews with meta-analysis that have shown no reduction in mortality with the use of inhaled nitric oxide (iNO) in patients with acute respiratory distress syndrome (ARDS). Importantly, these reports fail to make a distinction between the pediatric and adult patient. The number of adult patients in these reviews are far greater than the number of pediatric patients, which makes it difficult to interpret the data regarding the role of iNO on the pediatric population. Extrapolating data from the adult population to the pediatric population is complicated as we know that physiology and the body’s response to disease can be different between adult and pediatric patients. iNO has been demonstrated to improve outcomes in term and near-term infants with hypoxic respiratory failure associated with pulmonary hypertension. Recently, Bronicki et al. published a prospective randomized control trial investigating the impact of iNO on the pediatric patient population with acute respiratory failure. In this study, a benefit of decreased duration of mechanical ventilation and an increased rate of ECMO-free survival was demonstrated in patients who were randomized to receiving iNO, suggesting that there may be benefit to the use of iNO in pediatric ARDS (PARDS) that has not been demonstrated in adults. iNO has repeatedly been shown to transiently improve oxygenation in all age groups, and yet neonates and pediatric patients have shown improvement in other outcomes that have not been seen in adults. The mechanism that explains improvement with the use of iNO in these patient populations are not well understood but does not appear to be solely a result of sustained improvement in oxygenation. There are physiologic studies that suggest alternative mechanisms for explaining the positive effects of iNO, such as platelet aggregation inhibition and reduction in systemic inflammation. Hence, the role of iNO by various mechanisms and in various age groups warrants further investigation.

Characteristics and outcomes of patients treated with airway pressure release ventilation for acute respiratory distress syndrome: A retrospective observational study

BackgroundThe optimal mode of ventilation in acute respiratory distress syndrome (ARDS) remains uncertain. Airway pressure release ventilation (APRV) is a recognized treatment for mechanically-ventilated patients with severe hypoxaemia. However, contemporary data on its role as a rescue modality in ARDS is lacking. The goal of this study was to describe the clinical and physiological effects of APRV in patients with established ARDS. MethodsThis retrospective observational study was performed in a 23-bed adult intensive care unit in a tertiary extracorporeal membrane oxygenation (ECMO) referral centre. Patients with ARDS based on Berlin criteria were included through a prospectively-collected APRV database. Patients receiving APRV for less than six hours were excluded. ResultsFifty patients fulfilled the eligibility criteria. Prior to APRV initiation, median Murray Lung Injury Score was 3.5 (interquartile range (IQR) 2.5–3.9) and PaO2/FiO2 was 99mmHg (IQR 73–137). PaO2/FiO2 significantly improved within twenty-four hours post-APRV initiation (ANOVA F(1, 27)=24.34, P<.005). Two patients (4%) required intercostal catheter insertion for barotrauma. Only one patient (2%) required ECMO after APRV initiation, despite a majority (68%) fulfilling previously established criteria for ECMO at baseline. Hospital mortality rate was 38%. ConclusionsIn patients with ARDS-related refractory hypoxaemia treated with APRV, an early and sustained improvement in oxygenation, low incidence of clinically significant barotrauma and progression to ECMO was observed. The safety and efficacy of APRV requires further consideration.

The effects of pleural fluid drainage on respiratory function in mechanically ventilated patients after cardiac surgery

BackgroundPleural effusions occur commonly after cardiac surgery and the effects of drainage on gas exchange in this population are not well established. We examined pulmonary function indices following drainage of...

Hepatopulmonary syndrome in children-an update

Hepato-pulmonary syndrome (HPS) is an uncommon complication of liver disease. It can be acute or chronic and occur with or without portal hypertension. The reported frequency of HPS in patients with liver disease ranges between 4% and 32%. It occurs as a result of vasodilatation of the pulmonary vasculature which is most likely to be mediated by nitric oxide (NO). Three components are essential to the definition of HPS: 1. liver disease, 2. intra-pulmonary vascular dilatation (IPVD) and 3. impaired oxygenation. .Disease severity is determined by quantifying the degree of oxygenation impairment. Contrast enhanced echocardiography (CE-TTE) and Tc-99 labeled macro-aggregated albumin lung scan with uptake in brain are the gold standard investigations to diagnose HPS and plan management. Clinical features which are characteristic of HPS include orthodeoxia and platypnea in the presence of liver disease. Although there are anecdotal reports on the use of several drugs in the medical management of HPS, none have been shown to result in either sustained improvement in oxygenation or reduce mortality. Liver transplantation is possible and no longer considered to be contraindicated in HPS. However it is important to carefully select and prioritize patients with HPS for liver transplantation for optimum results.

High-Frequency Oscillatory Ventilation with Low Oscillatory Frequency in Pulmonary Interstitial Emphysema

Background: Pulmonary interstitial emphysema (PIE) is a common respiratory illness in preterm infants associated with significant morbidity and mortality for which the ventilatory management is imperfect. Objectives: To evaluate the impact of high-frequency oscillatory ventilation (HFOV) with a low oscillatory frequency and thus prolonged expiratory time in preterm infants with severe PIE. Methods: In a retrospective cohort study, preterm infants ≤30 weeks' gestation with radiological findings of severe PIE, and either high FiO₂ or persistent respiratory acidosis were studied if managed on HFOV with a low frequency (5-6 Hz, inspiratory time 30%) for >24 h. Trends in physiological and ventilatory parameters were examined over the first 72 h, radiological changes noted, and in-hospital outcomes ascertained. Results: 19 cases were identified and analysed in two groups: 14 with bilateral and 5 with predominantly unilateral disease. After transition to low-frequency HFOV, physiological responses were seen in both groups, in particular a rapid and sustained improvement in oxygenation in the bilateral group (mean (SD) alveolar-arterial oxygen difference at baseline: 404 ± 206 mm Hg; 4 h post-transition: 262 ± 181 mm Hg; 72 h: 155 ± 74 mm Hg; p = 0.0003). This occurred following a reduction in mean airway pressure (mean (SD) baseline: 14 ± 3.9 cm H₂O; 72 h: 12 ± 2.9 cm H₂O; p = 0.011). In the unilateral group, radiological resolution of PIE was observed on re-inflation following collapse of the affected lung. Overall, 15 infants survived, including 10 of the bilateral cases (71%), and all of the unilateral cases. Conclusion: HFOV with a low oscillatory frequency may afford benefit in preterm babies with severe PIE.

Inhaled nitric oxide in patients with the acute respiratory distress syndrome secondary to the 2009 influenza A (H1N1) infection in Canada

H1N1 had a self-limited respiratory illness; however, if hospitalization was required, 20-36% of patients required admission to the intensive care unit (ICU), and 80% of those patients required invasive mechanical ventilation. The case mortality ranged from 17-40%. In many of these patients, conventional mechanical ventilation strategies were not adequate to reverse their severe oxygenation defects. Adjunctive therapies in addition to lung protective mechanical ventilation strategies are often trialed in patients with oxygenation failure (defined as PaO2 60 mmHg despite FIO2 of 1.0 and optimal positive endexpiratory pressure [PEEP]). Inhaled nitric oxide (iNO) is one such therapy that has shown an improvement in oxygenation in patients with acute respiratory distress syndrome (ARDS). 2,3 In this report, we describe the epidemiologic characteristics, clinical features, treatment, and outcome in the cohort of patients who had ARDS due to H1N1 and were treated with iNO, and we compare their results with those of patients who did not receive iNO. Following approval by the University of Manitoba Biomedical Research Ethics Board, we conducted a retrospective chart review of all patients who presented with confirmed H1N1 and were treated with iNO in the teaching intensive care units at the University of Manitoba’s two adult medical intensive care units. Baseline demographic and clinical data of patients are shown in the Table. After administration of iNO, there was a significant and sustained improvement in the PaO2 and PaO2 /F IO2 ratio at 24 hr, and this improvement persisted throughout the study period (seven days). Three patients in the iNO group eventually required extracorporeal membrane oxygenation due to their profound ARDS. There were two deaths in the iNO group (n = 9) vs ten deaths in the control group (n = 94), 22% and 11%, respectively. Previous work has shown only a transient improvement in these parameters that, in many cases, did not persist past 24 hr. This result is significant as it shows a sustained improvement in oxygenation in these patients with viral pneumonia.

The Role of Neuromuscular Blockers in Early ARDS

The use of neuromuscular blocking agents (NMBAs) in patients with acute respiratory distress syndrome (ARDS) and acute lung injury (ALI) remains controversial. However, NMBAs are used in 25% to 45% of ALI/ARDS patients for a mean period of 1±2 days, especially in severe ARDS. Hypoxemia and facilitation of mechanical ventilation are the main indications of NMBAs. Three randomized, controlled trials showed that the systematic early use of NMBAs is associated with a sustained improvement in oxygenation in ARDS patients. The most recent trial reported a decrease in 90-day in-hospital mortality rate when severe ARDS patients received a short course of muscle relaxants. The use of NMBAs in the early phase of ARDS could reinforce the beneficial effects of a lung-protective ventilation strategy. However, the role of prolonged NMBA administration in intensive care unit–acquired paresis in ARDS patients remains largely questioned. This review analyzes the recent findings in the literature concerning the effects of NMBAs on gas exchange and patient outcomes, and their potential adverse effects in ARDS.

High-Frequency Oscillatory Ventilators in Burn Patients

The objective of the study is to review a single institution's experience with high-frequency oscillatory ventilation (HFOV) and compare patient characteristics, outcomes, and complications with other reported studies of HFOV use in burn patients with acute respiratory distress syndrome and respiratory failure. This study is a retrospective chart review of the burn patients treated with HFOV in Pediatric Burn Unit at Riley Hospital for Children from October 1996 to April 2007. Patient data were collected, including demographics, percentage of TBSA burn, percentage of full-thickness burn, mechanisms of burn, settings on conventional mechanical ventilation and HFOV, and blood gas data before initiation of HFOV and at 1, 3, 6, 12, 24, 72 (3 days), 120 (5 days), 168 (7 days), 240 (10 days), and 336 hours (14 days). Length of stay, mortality, and complications were also included. HFOV was used 24 times in 21 patients between October 1996 and April 2007 with a mean age of 10 ± 11 years. At initiation of HFOV, the PaO2/FiO2 and oxygenation index values were 109 ± 26 and 36 ± 12, respectively. At stop, the PaO2/FiO2 improved to 166 ± 24 with an average increase from before HFOV of 57 ± 39 (P < .002). At 5 days of HFOV, oxygenation index improved to 14.1 ± 1.7 (P < .02) but did not significantly improve at discontinuation of HFOV at 28.8 ± 6.2 (P = .11). The mortality rate during admission to the burn unit was 29%. Barotrauma occurred in 38% of patients during HFOV. Severe hypercapnea was present briefly in 49% of patients, and this was refractory to standard treatment in 19%. In our experience, HFOV in severe burn patients has significant, early, and sustained improvement in oxygenation. Earlier institution of HFOV seems to significantly lower rates of barotraumas.

Paralytics in critical care: not always the bad guy

The use of neuromuscular blocking agents (NMBAs) in patients with acute respiratory distress syndrome (ARDS) and acute lung injury remains controversial, although frequent. This review analyzes the effects of NMBAs on thoracopulmonary mechanics, gas exchange, patient outcome and their potential adverse effects. NMBAs are used in 25-45% of acute lung injury/ARDS patients for a mean period of 12 days, especially in severe ARDS. Hypoxemia and facilitation of mechanical ventilation are the main indications of NMBAs. Two randomized controlled trials showed that the systematic early use of NMBAs is associated with a sustained improvement in oxygenation in ARDS patients. The most recent suggests a beneficial effect on proinflammatory response associated with ARDS and mechanical ventilation. The use of NMBAs in acute lung injury/ARDS patients is not marginal. Recent studies suggest a beneficial effect of early use of NMBAs on oxygenation and inflammation. The role of NMBAs in the occurrence of ICU-acquired neuromyopathies and lung atelectasis in ARDS patients remains largely questioned. The use of NMBAs in the early phase of ARDS could reinforce the beneficial effects of a lung-protective ventilation. In this context, the effect of NMBAs on the outcome of ARDS patients must be evaluated.

Effect of mechanical ventilation in the prone position on clinical outcomes in patients with acute hypoxemic respiratory failure: a systematic review and meta-analysis

Mechanical ventilation in the prone position is used to improve oxygenation in patients with acute hypoxemic respiratory failure. We sought to determine the effect of mechanical ventilation in the prone position on mortality, oxygenation, duration of ventilation and adverse events in patients with acute hypoxemic respiratory failure. In this systematic review we searched MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials and Science Citation Index Expanded for articles published from database inception to February 2008. We also conducted extensive manual searches and contacted experts. We extracted physiologic data and clinically relevant outcomes. Thirteen trials that enrolled a total of 1559 patients met our inclusion criteria. Overall methodologic quality was good. In 10 of the trials (n = 1486) reporting this outcome, we found that prone positioning did not reduce mortality among hypoxemic patients (risk ratio [RR] 0.96, 95% confidence interval [CI] 0.84-1.09; p = 0.52). The lack of effect of ventilation in the prone position on mortality was similar in trials of prolonged prone positioning and in patients with acute lung injury. In 8 of the trials (n = 633), the ratio of partial pressure of oxygen to inspired fraction of oxygen on day 1 was 34% higher among patients in the prone position than among those who remained supine (p < 0.001); these results were similar in 4 trials on day 2 and in 5 trials on day 3. In 9 trials (n = 1206), the ratio in patients assigned to the prone group remained 6% higher the morning after they returned to the supine position compared with patients assigned to the supine group (p = 0.07). Results were quantitatively similar but statistically significant in 7 trials on day 2 and in 6 trials on day 3 (p = 0.001). In 5 trials (n = 1004), prone positioning was associated with a reduced risk of ventilator-associated pneumonia (RR 0.81, 95% CI 0.66-0.99; p = 0.04) but not with a reduced duration of ventilation. In 6 trials (n = 504), prone positioning was associated with an increased risk of pressure ulcers (RR 1.36, 95% CI 1.07-1.71; p = 0.01). Most analyses found no to moderate between-trial heterogeneity. Mechanical ventilation in the prone position does not reduce mortality or duration of ventilation despite improved oxygenation and a decreased risk of pneumonia. Therefore, it should not be used routinely for acute hypoxemic respiratory failure. However, a sustained improvement in oxygenation may support the use of prone positioning in patients with very severe hypoxemia, who have not been well-studied to date.

The short‐term effect of hyperoncotic albumin, given alone or with furosemide, on oxygenation in sepsis‐induced Acute Respiratory Distress Syndrome

Two prospective non-randomised interventional case series were conducted consecutively at a single university hospital mixed intensive care unit, in patients with severe sepsis and acute respiratory distress syndrome. The first series describes the administration of 200 ml of 20% human albumin solution over 120 s in 13 patients, examining the hypothesis that raising plasma albumin should improve oxygenation. The second series describes the effect of administering 30 mg of furosemide intravenously along with the albumin in 15 patients, exploring whether this would produce more sustained improvement in oxygenation than albumin only. Oxygenation and haemodynamic parameters were measured for 4 h, during the period of peak oncotic effect. Hyperoncotic albumin given alone or with furosemide produced only transient improvement in oxygenation and haemodynamics, which was statistically significant only in the patients given albumin alone. Although the plasma albumin remained significantly elevated at 4 h in both series, no sustained improvement in oxygenation was seen.

The Effects of Neuromuscular-Blocking Agents on Gas Exchange in Patients With Acute Respiratory Distress Syndrome

In Brief The use of neuromuscular-blocking agents (NMBA) in ventilated patients with acute respiratory distress syndrome (ARDS) is controversial and largely empiric. Few trials looked at their effectiveness on gas exchange or in improving lung mechanics in patients with ARDS. Only one randomized, controlled trial compared the effects of NMBA on gas exchange in patients with ARDS receiving NMBA as compared with patients receiving placebo throughout a period of 48 hours. In this trial, the early use of NMBA in patients with ARDS was associated with a sustained improvement in oxygenation. The muscular paralysis induced by NMBA could reduce the consumption of oxygen linked to the work of breathing. Muscular paralysis could facilitate mechanical ventilation by preventing spontaneous breaths responsible for the dys-synchrony and worsening of gas exchange. Muscular paralysis could increase compliance of the thoracic wall and improve mechanical ventilation during ARDS. However, these hypotheses are controversial. Finally, preliminary data show that the muscular paralysis could provide better adaptation to mechanical ventilation and better satisfaction with the protective criteria for reduction of ventilator-associated lung injuries by homogenizing the distribution of tidal volume and positive end expiratory pressure. The role of new NMBA (benzylisoquinolines) in the occurrence of critical illness neuromyopathy is largely questioned in the recent literature. It is important to design new studies to explain the mechanisms of the improvement in oxygenation associated with NMBA and to evaluate whether the use of NMBA modifies the outcome of patients with ARDS. The administration of neuromuscular-blocking agents (NMBA) in the early phase of acute respiratory distress syndrome is associated with a sustained improvement in oxygenation. Preliminary study shows that NMBA could reinforce the beneficial effects of lung-protective ventilation.

Effets de la curarisation sur les échanges gazeux lors du syndrome de détresse respiratoire aiguë

The use of neuromuscular blocking agents (NMBA) in ventilated patients with acute respiratory distress syndrome (ARDS) is controversial and largely empirical. Few trials looked at their effectiveness on gas exchange or in improving lung mechanics in patients with ARDS. Only one randomized controlled trial compare the effects of NMBA on gas exchange in patients with ARDS receiving NMBA as compared with patients receiving placebo throughout a period of 48 hours. In this trial, the early use of NMBA in patients with ARDS was associated with a sustained improvement in oxygenation. The muscular paralysis induced by NMBA could reduce the consumption of oxygen linked to the work of breathing. Muscular paralysis could facilitate mechanical ventilation by preventing spontaneous breaths responsible for the dyssynchrony and worsening of hematosis. Muscular paralysis could increase compliance of the thoracic wall and improve mechanical ventilation during ARDS. However, these hypotheses are controversial. Finally, preliminary data show that the muscular paralysis could provide better adaptation to mechanical ventilation and better satisfaction with the protective criteria for reduction of ventilator-associated lung injuries by homogenizing the distribution of tidal volume and positive end-expiratory pressure. The role of new neuromuscular blocking agents (benzylisoquinolines) in the occurrence of critical illness neuromyopathy is largely questioned in the recent literature. It is important to design new studies to explain the mechanisms of the improvement in oxygenation associated with NMBA and to evaluate whether the use of NMBA modifies the outcome of patients with ARDS.

Combining high-frequency oscillatory ventilation and recruitment maneuvers in adults with early acute respiratory distress syndrome: The Treatment with Oscillation and an Open Lung Strategy (TOOLS) Trial pilot study*

To determine the safety, feasibility, and lung-recruitment efficacy of an explicit ventilation protocol combining high-frequency oscillatory ventilation and recruitment maneuvers. Prospective, multiple-center, single-intervention pilot study. Four university-affiliated intensive care units. Twenty-five patients with early acute respiratory distress syndrome and severe oxygenation failure. Patients were transitioned from standardized conventional ventilation to high-frequency oscillatory ventilation beginning with an initial cycle of up to three sustained inflation recruitment maneuvers (40 cm H2O x 40 secs), followed by a decremental titration of Fio2 and then mean airway pressure. Recruitment maneuvers were repeated for hypoxemia and routinely at least twice daily if the Fio2 was >0.4. A specific protocol was used for weaning high-frequency oscillatory ventilation, for transitioning to conventional ventilation, and for judging intolerance of conventional ventilation whereby patients should be put back on high-frequency oscillatory ventilation. Patients (median [interquartile range] Acute Physiology and Chronic Health Evaluation II, 24 [19-32]; age, 50 [41-64]) were enrolled after 13 (range, 6-51) hrs of conventional ventilation. Following the initial cycle of recruitment, the mean (+/-sd) Pao2/Fio2 increased significantly compared with standardized conventional ventilation (200 +/- 117 vs. 92 +/- 36 mm Hg, p < .001). After a mean of 12 hrs of high-frequency oscillatory ventilation, the mean Fio2 was significantly reduced compared with prestudy levels (0.5 +/- 0.2 vs. 0.9 +/- 0.1, p < .001). A median of seven (four to 11) recruitment maneuvers was performed per patient over the study period, with only eight of 244 (3.3%) being aborted. Six of 19 patients transitioned to conventional ventilation (32%) were deemed intolerant and were switched back to high-frequency oscillatory ventilation. Protocol adherence was excellent with documented rates >90%. The combination of high-frequency oscillatory ventilation and recruitment maneuvers resulted in rapid and sustained improvement in oxygenation, likely through lung recruitment. This explicit high-frequency oscillatory ventilation protocol appears well tolerated, feasible, and physiologically sound.

Recruitment maneuvers during prone positioning in patients with acute respiratory distress syndrome

To evaluate the interaction of recruitment maneuvers and prone positioning on gas exchange and venous admixture in patients with early extrapulmonary acute respiratory distress syndrome ventilated with high levels of positive end-expiratory pressure. We hypothesized that a sustained inflation performed after 6 hrs of prone positioning would induce sustained improvement in oxygenation (Pao2/Fio2) and venous admixture. Prospective, interventional study. Tertiary care, postoperative intensive care unit. Fifteen patients with early extrapulmonary acute respiratory distress syndrome. After 6 hrs of prone positioning, a sustained inflation was performed with 50 cm H2O maintained for 30 secs. Data were recorded in supine position, after 6 hrs of prone positioning, at 3, 30, and 180 mins following the sustained inflation. A response to prone positioning was observed in nine of 15 patients leading to an improvement of Pao2/Fio2 (147 +/- 37 torr vs. 225 +/- 77 torr, p = .005) and venous admixture (35.4 +/- 8.3% vs. 28.9 +/- 9.8%, p = .001). Six patients did not respond to prone positioning. Following the sustained inflation, the responders to prone positioning showed a further increase of Pao2/Fio2 and decrease of venous admixture at 3 mins (Pao2/Fio2, 225 +/- 77 torr vs. 368 +/- 90 torr, p = .018; venous admixture, 28.9 +/- 9.8% vs. 18.9 +/- 6.7%, p = .05). In all six nonresponders to prone positioning, an improvement of Pao2/Fio2 and venous admixture occurred at 3 mins following the sustained inflation (128 +/- 18 torr vs. 277 +/- 59 torr, p = .03; venous admixture, 34.2 +/- 6.0% vs. 23.8 +/- 6.3%, p = .05). The beneficial effects of the sustained inflation remained significantly elevated over 3 hrs in responders and nonresponders to prone positioning. In patients with early extrapulmonary acute respiratory distress syndrome, a sustained inflation performed after 6 hrs of prone positioning induced further and sustained improvement of oxygenation and venous admixture in both responders and nonresponders to prone positioning.

Use of inhaled nitric oxide during interhospital transport of newborns with hypoxemic respiratory failure.

Inhaled nitric oxide (iNO) therapy improves oxygenation and reduces the need for extracorporeal membrane oxygenation (ECMO) in near-term and term newborns with hypoxemic respiratory failure and pulmonary hypertension.1–4 The use of nitric oxide (NO) gas as an inhalational therapy for persistent pulmonary hypertension of the newborn (PPHN) was recently approved by the US Food and Drug Administration (FDA). Because iNO therapy has become adopted as a standard of care for PPHN, its use has increased in many centers without the capability of providing other rescue therapies, such as ECMO. Although iNO therapy is often effective, 30% to 40% of sick newborns do not have sustained improvement in oxygenation and hemodynamics after the initiation of therapy. Patients in whom iNO fails are critically ill and often require rapid transfer to an ECMO center. Abrupt discontinuation of iNO therapy before transport, even in patients who have had little apparent clinical benefit, can be dangerous because of acute deterioration with severe hypoxemia.5–7 The use of iNO for the stabilization and transport of such neonates has been previously described5; however, since this report, at least 1 death has been associated with the discontinuation of iNO before transport to an ECMO center.8 Thus, the availability of iNO therapy during transport is vital to its safe and effective application. In this report, we describe: 1) a practical approach to stabilization and transport of critically ill newborns with iNO therapy; 2) the clinical course of newborns treated with iNO during transport; and 3) a survey of the current availability of iNO therapy for transport to ECMO centers in the United States. ### iNO Therapy During Transport—Program Development To determine a practical approach to the stabilization and transport of critically ill newborns, we studied 3 different transport iNO systems. The NO gas used for each … Address correspondence to John P. Kinsella, MD, Division of Neonatology, Box B-070, Children’s Hospital, 1056 E 19th Ave, Denver, CO 80218-1088. E-mail: john.kinsellauchsc.edu

Partial liquid ventilation with perfluorocarbons for treatment of ARDS in burns

Pulmonary failure remains the major determinant of mortality and morbidity following burn injury. We hypothesized that intratracheal instillation of perfluorocarbon liquids could be a therapeutic measure in combination with conventional mechanical ventilation to improve pulmonary gas exchange in acute respiratory distress syndrome with thermal injury. Forty-five New Zealand rabbits were used for this prospective and randomized experimental study. The animals were burned by scald to reach full-thickness 40% burn surface area. After inducing respiratory distress by repeated lung lavage with saline, animals were divided randomly into three groups of 15 rabbits each. First group (control group) received conventional treatment (continuous positive-pressure ventilation) using a FiO 2 of 1.0, tidal volume of 12 ml/kg, respiratory frequency of 30 cycles/min and PEEP of 6 cm H 2O. Second group was treated with 9 ml/kg of intratracheal perfluorocarbon. Third group was treated with 15 ml/kg of intratracheal perfluorocarbon. All groups were ventilated for 6 h. In the perfluorocarbon groups, PaO 2 increased significantly ( P<0.05) from 46±4 to 439±10 mmHg compared to the control group in a dose-related manner. In pulmonary parameters we observed significant ( P<0.05) decrease in mean airway pressures from the pre-treatment value of 11.44±0.15 cm H 2O to the post treatment 10.22±0.12 cm H 2O and increase ( P<0.05) in respiratory system compliance from 1.8±0.02 to 2.46±0.07 ml/cm H 2O with the perfluorocarbon. Perfluorocarbon instillation did not result in statistically significant changes in arterial pressure, heart rate and central venous pressure. In conclusion, partial liquid ventilation with perfluorocarbon is a new technique leading to a marked and sustained improvement in oxygenation and pulmonary function in an experimental model of ARDS in burns.