Improvement In Oxygenation Index Research Articles

High Frequency Oscillatory Ventilation (HFOV) and Inhaled Nitric Oxide (iNO) Use During Neonatal Emergency Transport - Feasibility and Efficacy in India.

A retrospective studyof 24 neonates to evaluate the feasibility and efficacy of high frequency oscillatory ventilation (HFOV) and inhaled nitric oxide (iNO) for transferring critically ill neonates to tertiary neonatal intensive care, who were transported by road ambulance was done. Efficacy was measured by clinical improvement, patient safety was assessed by comparing cardiorespiratory indicators before and after transport, and adverse events during transport. Significant oxygenation improvement was observed in neonates transported with HFOV ± iNO compared to earlier ventilator settings. Pre- and post-transport vital signs were stable, and no transport-related deaths occurred. A substantial rise in median SpO2 was seen after transfer [86 (81, 91) vs. 93 (89, 97) before transport, p <0.001]. Twelve of twenty-one newborns who received nitric oxide demonstrated significant improvement in oxygenation index (a 10% decrease from prior value). Overall survival was 70.8%, however non-transfer or inadequate respiratory treatment may have exacerbated mortality.

Positioning for acute respiratory distress in hospitalised infants and children.

Positioning for acute respiratory distress in hospitalised infants and children.

Efficacy of therapeutic plasma exchange in the treatment of penn class 3 and 4 cytokine release syndrome complicating COVID-19

ObjectivesCytokine release syndrome (CRS) is a potentially severe complication of COVID-19 most commonly resulting in respiratory failure. This ten-patient study was designed to determine the efficacy of therapeutic plasma exchange (TPE) in improving oxygenation and in reducing the cytokine load in a critically ill subset of patients. MethodsFive single volume plasma exchanges over eight days within a 14-day study period. In mechanically ventilated patients, oxygenation was measured via the PaO2/FiO2 (P/F) ratio and the oxygenation index (OI) daily for 14 days. Supplemental oxygen requirements were tracked daily for non-ventilated patients. ResultsNon-ventilated patients were liberated from supplemental oxygen after TPE. The response was rapid with an 87% average reduction in oxygenation requirements following and average time to return to room air of 5.25 days. All mechanically ventilated patients demonstrated improvement in oxygenation with a 78% average improvement in the P/F ratio and a 43% improvement in OI. C-reactive protein (CRP) and serum levels of IL-6, IL-8, IL-10, TNFα, IFNγ and GM-CSF, were measured daily with immediate post TPE levels drawn on days 1, 2, 4, 6 and 8. All patients demonstrated significant reductions in CRP, IL-6, IL-10 and TNFα. ConclusionsIn the majority of patients with Penn class 3 and 4 CRS complicating COVID-19, TPE demonstrated a prompt improvement in oxygenation and reduction in cytokine load without compromising patient safety. As this pilot study was envisioned to be hypothesis generating, expanded trials using TPE alone and in conjunction with novel pharmacologic agents are warranted. RegistrationClinicalTrials.gov NCT04374149.

Effect of low-dose exogenous surfactant on infants with acute respiratory distress syndrome after cardiac surgery: a retrospective analysis

BackgroundAcute respiratory distress syndrome (ARDS) in infants undergoing cardiac surgery is associated with significant mortality and prolonged ventilation; surfactant administration may be a useful therapy. The purpose of this study is to evaluate the effect of low-dose exogenous surfactant therapy on infants suffering ARDS after cardiac surgery.MethodsWe conducted a case-control study of infants diagnosed with moderate-to-severe ARDS (PaO2/FiO2 < 150) after cardiac surgery. A case was defined as a patient that received surfactant and standard therapy, while a control was defined as a patient that underwent standard therapy. The primary endpoint was the improvement in oxygenation index (OI) after 24-h of surfactant treatment; and secondary endpoints were the ventilator time and PICU time.ResultsTwenty-two infants treated with surfactant were matched with 22 controls. Early low-dose (20 mg/kg) surfactant treatment was associated with improved outcomes. After surfactant administration for 24-h, the surfactant group was much better compared with the control group at the 24-h in OI (difference in average change from baseline, − 6.7 [95% CI, − 9.3 to − 4.1]) (P < 0.01) and ventilation index (VI, mean difference, − 11.9 [95% CI, − 18.1 to − 5.7]) (P < 0.01). Ventilation time and PICU time were significantly shorter in the surfactant group compared with the control group (133.6 h ± 27.2 vs 218.4 h ± 28.7, P < 0.01; 10.7d ± 5.1 vs 17.5d ± 6.8, P < 0.01). Infants in the surfactant group under 3 months benefit more from OI and VI than the infants over 3 months in a preliminary exploratory analysis.ConclusionsIn infants with moderate-to-severe ARDS after cardiac surgery, early low-dose exogenous surfactant treatment could prominently improve oxygenation and reduce mechanical ventilation time and PICU time. Infants younger than 3 months may get more benefit of oxygenation than the older ones. Randomized controlled trials are needed to explore the effect of surfactant to ARDS of cardiac surgical infants.

Hypothermia alleviated LPS-induced acute lung injury in Rat models through TLR2/MyD88 pathway

Acute lung injury (ALI) is a common clinical syndrome in ICU departments with high mortality. The pathology of ALI is still not clear and there is no specific and efficient treatment against ALI. In this study, we established ALI rat model through lipopolysaccharide administration. We found that hypothermia therapy led to significant improvement in oxygenation index, edema formation and pathological score, demonstrating that hypothermia is beneficial to the recovery of lung function and alleviation of lung injury. Besides, hypothermia resulted in a decrease in plasminogen activator inhibitor-1(PAI-1) concentration, showing the inflammation was partially inhibited. This was also confirmed by a decrease in TNF-α mRNA and protein level in hypothermia group. The effect of hypothermia was mediated by TLR2/MyD88 signaling, which led to the alteration in NF-κB p65 level. Collectively, this study indicated that hypothermia therapy was potentially an efficient therapy against ALI.

Abstract O-16: THE RESPONSE TO LOW DOSE METHYLPREDNISOLONE THERAPY FOR PAEDIATRIC ACUTE RESPIRATORY DISTRESS SYNDROME (PARDS) - A RETROSPECTIVE OBSERVATIONAL STUDY.

Aims & Objectives: A recent meta-analysis in adult ARDS patients found improved mortality with methylprednisolone, but there remains a lack of level 1 evidence in paediatrics (1).This study aims to characterise response to steroid treatment in paediatric patients with severe pARDS treated in two PICUs. Methods A retrospective, observational study, included all patients prescribed IV methylprednisolone for the indication of pARDS between January 2011 and December 2016. All patients met the PALICC definition of pARDS, and were prescribed IV methylprednisolone (2mg/kg/day). Oxygenation index (OI) was evaluated daily, from admission until 7 days after methylprednisolone initiation. Results 84 patients met inclusion criteria. Median age was 9 months. 52 patients survived to ICU discharge (62%). A multi-linear regression analysis demonstrates improvement in mean OI in the 7 days following steroid administration (figure 1). 63 patients had an arterial catheter at the time of steroid commencement, and of these, 49 (77%) had a >20% improvement in OI following steroid administration. 80% of patients who demonstrated any improvement in OI did so in <72hrs. These patients were classified as ‘responders’ (n=38, 60%). Baseline characteristics were similar between ‘responders’ and ‘non-responders’. Univariable analysis showed a significant difference in VFD (p<0.05) between responders and non-responders. On a multivariable analysis including likely cofounders, response to steroids did not independently predict VFD.Conclusions Improvement in OI following administration of IV methylprednisolone for pARDs occurred within 3 days of commencement in most patients. These data can be used to inform the design of future trials of steroids in pARDS. 1. Meduri GU et al.Intensive Care Med. 2016 May;42(5):829–840.

Severe ARDS due to Influenza A (H1N1) pdm09 Infection During Pregnancy Followed by Intrauterine Fetal Death at Alka Hospital, Lalitpur

Pandemic due to Influenza A (H1N1) pdm 09 has been a significant cause of morbidity and mortality worldwide. Pregnant women are at risk of severe disease and ARDS, with rapid progression of disease. There is increased risk of fetal loss. Little evidence exists regarding the management of ARDS in pregnancy. Here we report a case of H1N1 virus infection in a pregnant woman in third trimester complicated by severe ARDS and intra-uterine fetal death. Fetus was successfully expelled using vaginal Misoprostol, which was followed by improvement in oxygenation indices. However, the patient died of refractory hypotension. Influenza vaccination in the high risk population may be invaluable. Birat Journal of Health Sciences Vol.2/No.1/Issue 2/ Jan - April 2017, Page: 227-229

Role of High frequency oscillatory mode of ventilation (HFOV) as a rescue treatment in newborns with impending respiratory failure after failed conventional mode of ventilation

Introduction: High frequency oscillatory ventilation (HFOV) is a new mode of mechanical ventilation which by safer use of mean airway pressure higher than that used during conventional ventilation (CV) is better lung safety strategy in respiratory failure. Aims and Objectives: To study the role of high frequency oscillatory ventilation at a tertiary NICU as rescue mode in neonates with severe respiratory failure. Materials and Methods: 31 neonates admitted in NICU failing conventional mode of ventilation were studied prospectively from January 2014 to September 2015. Babies with respiratory failure failing conventional mode of ventilation were shifted to HFOV. On HFOV, babies were initially started on mean airway pressure 2 cm higher than on conventional ventilation and increased until a saturation of &gt;95% is achieved. Neonates were again weaned off to CV, when target goals of oxygenation and ventilation were reached. Improvements were assessed periodically by arterial blood gas analysis (ABG) and other parameters. Results: 31 neonates were shifted to HFOV as rescue therapy and primary outcome was improvement in oxygenation index and alveolar arterial oxygen radiant (A-aDO2) which were compared and also showed significant impact on secondary outcome of survival. Majority of neonates with primary diagnosis as meconium aspiration syndrome, congenital pneumonia showed 100% recovery. PPHN babies had 78% recovery, while babies with pulmonary haemorrhage had poor outcome. There was statistically significant improvement in oxygenation index and A-aDO2 in 15 babies after shifting to HFOV. Thus, the study shows that HFOV can be used as rescue therapy for neonates after failing conventional ventilation.

Endothelin receptor antagonists for persistent pulmonary hypertension in term and late preterm infants.

Endothelin, a powerful vasoconstrictor, is one of the mediators in the causation of persistent pulmonary hypertension of the newborn (PPHN). Theoretically, endothelin receptor antagonists (ETRA) have the potential to improve the outcomes of infants with PPHN. To assess the efficacy and safety of ETRA in the treatment of PPHN in full-term, post-term and late preterm infants.To assess the efficacy and safety of selective ETRAs (which block only the ETA receptors) and non-selective ETRAs (which block both ETA and ETB receptors) separately. CENTRAL (Cochrane Central Register of Controlled Trials), MEDLINE, EMBASE and CINAHL databases were searched until December 2015. Randomised, cluster-randomised or quasi-randomised controlled trials were eligible. Two review authors independently searched the literature, selected the studies, assessed the risk of bias and extracted the data. A fixed-effect model was used for meta-analysis. We used the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach to assess the quality of evidence. Two randomised controlled trials of ETRA met the inclusion criteria. Both studies utilized oral Bosentan. The first study was done in a setting where inhaled nitric oxide (iNO) therapy was not available. Forty-seven infants (≥ 34 weeks' gestation) were randomised to receive either Bosentan or placebo. The second study was a multicentre study where iNO therapy was the standard of care for PPHN. Twenty-one infants were randomised to receive either 'iNO plus Bosentan' or 'iNO plus placebo'.In the first study, there was no significant difference in the incidence of death before hospital discharge between the Bosentan and placebo groups (1/23 vs 3/14; RR 0.20, 95% CI 0.02 to 1.77; RD -0.17, 95% CI -0.40 to 0.06). A higher proportion of infants in the Bosentan group showed improvement in oxygenation index (OI) at the end of therapy (21/24 vs 3/15; RR 4.38, 95% CI 1.57 to 12.17; RD 0.68, 95% CI 0.43 to 0.92; number needed to treat for a beneficial outcome (NNTB) 1.5). The duration of mechanical ventilation was lower in the Bosentan group (4.3 ± 0.9 vs 11.5 ± 0.6 days; MD -7.20, 95% CI -7.64 to -6.76). There was no significant difference in adverse neurological outcomes at six months (0/23 vs 4/14; RR 0.07, 95% CI 0.00 to 1.20; RD -0.29, 95% CI -0.52 to -0.05). The study suffered from a high risk of attrition bias since 8/23 infants in the placebo group were excluded from various analyses. Since the protocol for the study could not be accessed, the study suffered from unclear risk of reporting bias.In the second study, there was no significant difference in the incidence of treatment failure needing extracorporeal membrane oxygenation (ECMO) between the 'iNO plus Bosentan' vs 'iNO plus placebo' groups (1/13 vs 0/8; RR 1.93, 95% CI 0.09 to 42.35; RD 0.08, 95% CI -0.14 to 0.30). There was no significant difference in the median time to wean from iNO ('iNO plus Bosentan': 3.7 days (95% CI 1.17 to 6.95); 'iNO plus placebo': 2.9 days (95% CI 1.26 to 4.23); P = 0.34). There were no significant differences in the OI 0, 3, 5, 12, 24, 48 and 72 hours of treatment between the groups. There were no significant differences in the time to complete weaning from mechanical ventilation (median 10.8 days (CI 3.21 to 12.21) versus 8.6 days (CI 3.71 to 9.66); P = 0.24). The study had unequal distribution to the Bosentan group (N = 13) and the placebo group (N = 8). The methods used for generating random sequence numbers and allocation concealment were unclear, resulting in unclear risk of selection bias.Both studies reported that Bosentan was well tolerated and no major adverse effects were noted. Data from the two studies was not pooled given the heterogenous nature of the clinical settings and the modalities used for the treatment of PPHN.Overall, the quality of evidence was considered low, given the small sample size of the included studies, the numerical imbalance between the groups due to randomisation and attrition, and unclear risk of bias on some of the important domains. There is inadequate evidence to support the use of ETRAs either as stand-alone therapy or as adjuvant to inhaled nitric oxide in PPHN. Adequately powered RCTs are needed.

Intravenous iloprost and oral sildenafil as rescue medicine in newborns with persistent pulmonary hypertension resistant to conventional therapy

Objectives: To review the data of 11 term newborns with persistent pulmonary hypertension of the newborn (PPHN) resistant to conventional therapy and treated with intravenous (IV) iloprost and oral sildenafil as rescue medicine. Materials and Methods: Iloprost was started 2 ng/kg/min intravenously, if oxygenation index (OI) 25 in spite of conventional methods in 24 h. During follow-up, if OI remains 25, iloprost dosage was increased by 1 ng/kg/min by 6-h intervals. If there was improvement in OI in 24 h, treatment continued with IV iloprost and thereafter with inhaled iloprost during weaning. However, if there was no improvement in OI, treatment continued with 0.25 mg/kg/dose oral sildenafil given at 4 doses. If OI remains 25, sildenafil dosage was increased by 0.25 mg/kg at each following dose. Similarly, if there was improvement in OI in 24 h, treatment continued with oral sildenafil and thereafter with inhaled iloprost during weaning. Results: In 5 patients, treatment continued with oral sildenafil because of no response to IV iloprost. The treatment continued median 5 days in subjects given IV iloprost, and median 6 days with oral sildenafil. The extubation time was median 10 days and the follow-up continued median 17 days. The mean systolic pulmonary artery pressure was 63.3 mmHg before treatment, and 38.5 mmHg before discharge (P < 0.01). Ten of 11 subjects (% 91) were discharged and 1 subject died because of noncardiopulmonary reasons. Conclusion: These results showed that, the use of IV iloprost and oral sildenafil as rescue medicine in patients with resistant PPHN could be effective and safe.

Improved Oxygenation 24 Hours After Transition to Airway Pressure Release Ventilation or High-Frequency Oscillatory Ventilation Accurately Discriminates Survival in Immunocompromised Pediatric Patients With Acute Respiratory Distress Syndrome*

Children with an immunocompromised condition and requiring invasive mechanical ventilation have high risk of death. Such patients are commonly transitioned to rescue modes of nonconventional ventilation, including airway pressure release ventilation and high-frequency oscillatory ventilation, for acute respiratory distress syndrome refractory to conventional ventilation. Our aim was to describe our experience with airway pressure release ventilation and high-frequency oscillatory ventilation in children with an immunocompromised condition and acute respiratory distress syndrome refractory to conventional ventilation and to identify factors associated with survival. Retrospective cohort study. Tertiary care, university-affiliated PICU. Sixty pediatric patients with an immunocompromised condition and acute respiratory distress syndrome refractory to conventional ventilation transitioned to either airway pressure release ventilation or high-frequency oscillatory ventilation. None. Demographic data, ventilator settings, arterial blood gases, oxygenation index, and PaO(2)/FIO(2) were recorded before transition to either mode of nonconventional ventilation and at predetermined intervals after transition for up to 5 days. Mortality in the entire cohort was 63% and did not differ between patients transitioned to airway pressure release ventilation and high-frequency oscillatory ventilation. For both airway pressure release ventilation and high-frequency oscillatory ventilation, improvements in oxygenation index and PaO(2)/FIO(2) at 24 hours expressed as a fraction of pretransition values (oxygenation index(24)/oxygenation index(pre) and PaO(2)/FIO(224)/PaO(2)/FIO(2pre)) reliably discriminated nonsurvivors from survivors, with receiver operating characteristic areas under the curves between 0.89 and 0.95 (p for all curves < 0.001). Sensitivity-specificity analysis suggested that less than 15% reduction in oxygenation index (90% sensitive, 75% specific) or less than 90% increase in PaO(2)/FIO(2) (80% sensitive, 94% specific) 24 hours after transition to airway pressure release ventilation were the optimal cutoffs to identify nonsurvivors. The comparable values 24 hours after transition to high-frequency oscillatory ventilation were less than 5% reduction in oxygenation index (100% sensitive, 83% specific) or less than 80% increase in PaO(2)/FIO(2) (91% sensitive, 89% specific) to identify nonsurvivors. In this single-center retrospective study of pediatric patients with an immunocompromised condition and acute respiratory distress syndrome failing conventional ventilation transitioned to either airway pressure release ventilation or high-frequency oscillatory ventilation, improved oxygenation at 24 hours expressed as PaO(2)/FIO(224)/PaO(2)/FIO(2pre) or oxygenation index(24)/oxygenation indexpre reliably discriminates nonsurvivors from survivors. These findings should be prospectively verified.

Perfusion Index Variability in Preterm Infants Treated with Two Different Natural Surfactants for Respiratory Distress Syndrome

The objective of this study was to compare the perfusion index (PI) variability in premature infants with respiratory distress syndrome (RDS) following administration of two different natural surfactant preparations. This was a prospective study on 92 preterm infants with RDS. Patients were randomized into two groups. Group 1 (n = 46) received beractant; Group 2 (n = 46) received poractant alfa. Oxygen saturation, PI, and heart rate were measured by Masimo Rainbow SET Radical-7 pulse oximeter (Masimo Corp., Irvine, CA) before and after surfactant. The effects of the two treatment regimens on PI and oxygenation were compared. Repeated doses were more needed in beractant group (p = 0.04). Median oxygenation index (OI) before surfactant were similar, but improvement in OI was more prominent at 6th hour of surfactant in Group 2 (p = 0.001). Both groups had similar preductal PI values before surfactant. PI was higher at 6th hour of surfactant in Group 2 (p = 0.001). Pulmonary hemorrhage, intraventricular hemorrhage, patent ductus arteriosus, necrotizing enterocolitis, and mortality were more frequent in infants whose PI values lower than 0.7 within the first 5 days of life (p = 0.001). Poractant alfa resulted in more prominent improvement in PI and OI. Low PI values measured at early postnatal period may predict poor clinical outcome in preterm infants with RDS.

Vasopressin as a Rescue Therapy for Refractory Pulmonary Hypertension in Neonates

To determine the effect of vasopressin therapy on the efficacy of oxygenation and arterial pressure in infants with severe persistent pulmonary hypertension of the newborn. Retrospective case study. Neonatal ICU, Hospital for Sick Children, Toronto, Canada. Neonates with severe persistent pulmonary hypertension. Intravenous infusion of vasopressin. Ten infants satisfied the inclusion criteria. Inhaled nitric oxide was used for median (interquartile range) duration of 15 hours (11-28 hr) prior to vasopressin commencement. Vasopressin was initiated at a mean dose of 0.0002 ± 0.0002 U/kg/min for a median (interquartile range) duration of 49 hours (13-95 hr). Administration of vasopressin was associated with an improvement in oxygenation index, peak effect 6 hours after drug initiation (p = 0.01), and a reduction in inhaled nitric oxide dose (p < 0.05). There was a concomitant improvement in blood pressure (p < 0.05) and urine output (p < 0.05), without drop in the serum sodium level or worsening in serum lactate level. Although there is limited experience of vasopressin use in persistent pulmonary hypertension of the newborn infants, our case series suggests it to be a potential adjunctive therapy for improving the efficacy of oxygenation and systemic hypotension. A prospective randomized trial is needed to confirm its efficacy and safety in the management of severe persistent pulmonary hypertension of the newborn.

High-frequency percussive ventilation improves oxygenation and ventilation in pediatric patients with acute respiratory failure

PurposeHigh-frequency percussive ventilation (HFPV) in pediatrics has been described predominantly in burned patients. We aimed to describe its effectiveness and safety in noninhalational pediatric acute respiratory failure (ARF). MethodsWe conducted an observational study in a tertiary care pediatric intensive care unit on 31 patients with ARF failing conventional ventilation transitioned to HFPV. Demographics, ventilator settings, oxygenation index, oxygen saturation index, oxygen saturation as measured by pulse oximetry/fraction of inspired oxygen (Fio2), and Pao2/Fio2 were recorded before and during HFPV. ResultsInitiation of HFPV was associated with improvements in oxygenation index, oxygen saturation index, Pao2/Fio2, and oxygen saturation as measured by pulse oximetry/Fio2 as early as 12 hours (P < .05), which continued through 48 hours after transition. Improved oxygenation occurred without an increase in mean airway pressures. Reductions in Paco2 occurred 6 hours after initiation of HFPV and continued through 48 hours (P < .01). Improved gas exchange was accompanied by reduced peak-inflating pressures at all time intervals after initiation of HPFV (P < .01). Vasopressor scores were similar before and after initiation of HFPV in patients requiring vasoactive support. Twenty-six (83.9%) of 31 patients survived to hospital discharge. ConclusionsIn a heterogeneous population of pediatric ARF failing conventional ventilation, HFPV efficiently improves gas exchange in a lung-protective manner.

High frequency oscillation and airway pressure release ventilation in pediatric respiratory failure

Airway pressure release ventilation (APRV) and high frequency oscillatory ventilation (HFOV) are frequently used in acute lung injury (ALI) refractory to conventional ventilation. Our aim was to describe our experience with APRV and HFOV in refractory pediatric ALI, and to identify factors associated with survival. We analyzed 104 patients with hypoxemia refractory to conventional ventilation transitioned to either APRV or HFOV. Demographics, oxygenation index (OI), and PaO2 /FiO2 (PF ratio) were recorded before transition to either mode of nonconventional ventilation (NCV) and for every 12 hr after transition. Relative to APRV, patients on HFOV were younger and had more significant lung disease evidenced by higher OI (28.5 [18.6, 36.2] vs. 21.0 [15.5, 30.0], P = 0.008), lower PF ratios (73 [59,94] vs. 99 [76,131], P = 0.002), and more frequent use of inhaled nitric oxide. In univariate analysis, HFOV was associated with more frequent neuromuscular blockade. Forty-one of 104 patients died on NCV (39.4%). Survivors demonstrated improvement in OI 24 hr after transition to NCV, whereas non-survivors did not (12.9 [8.9, 20.9] vs. 28.1 [17.6, 37.1], P < 0.001). After controlling for immunocompromised status, number of vasopressors, and OI before transition, mode of NCV was not associated with mortality. In a heterogeneous PICU population with hypoxemia refractory to conventional ventilation transitioned to NCV, improvement in oxygenation at 24 hr was associated with survival. Immunocompromised status, number of vasopressor infusions, and the OI before transition to NCV were independently associated with survival.

Acute and sustained effects of aerosolized vs. bolus surfactant therapy in premature lambs with respiratory distress syndrome

Surfactant (SF) instillation may produce acute deleterious effects on gas exchange and both systemic and cerebral hemodynamics. Our aim was to compare the effects of aerosolized SF (SF-aero) with those of bolus SF (SF-bolus) administration on gas exchange, lung mechanics, and cardiovascular function in premature lambs with respiratory distress syndrome (RDS). Fourteen preterm lambs (85% gestation) were randomly assigned to receive SF-aero or SF-bolus. Oxygenation index (OI), PaCO2, cardiovascular parameters, carotid blood flow (CBF), lung compliance (mean dynamic compliance), and tidal volume (VT) were measured every 30 min for 6 h. Biochemical and histological analyses were performed. After delivery, lambs developed severe RDS (inspiratory fraction of oxygen: 1; pH < 7.15; PaCO2 > 80 mm Hg; PaO2 < 30 mm Hg, mean dynamic compliance < 0.08 ml/cm H2O/kg). By 60 min after treatment, both groups showed an improvement in OI, PaCO2, mean dynamic compliance, and VT that was maintained until the end of the experiment. PaCO2 and CBF increased significantly in the SF-bolus group during the first 15-30 min, without concomitant changes in cardiovascular parameters, whereas in the SF-aero group, PaCO2 and CBF decreased gradually. SF-aero induced less alveolar hemorrhage and inflammation. SF-aero produced improvements in gas exchange and lung mechanics similar to those produced by bolus administration but with less lung injury and fewer cerebral hemodynamic changes.

Comparison of two ventilation modes in post-cardiac surgical patients

Background:The cardiopulmonary bypass (CPB)-associated atelectasis accounted for most of the marked post-CPB increase in shunt and hypoxemia. We hypothesized that pressure-regulated volume-control (PRVC) modes having a distinct theoretical advantage over pressure-controlled ventilation (PCV) by providing the target tidal volume at the minimum available pressure may prove advantageous while ventilating these atelactic lungs.Methods:In this prospective study, 36 post-cardiac surgical patients with a PaO2/FiO2 (arterial oxygen tension/Fractional inspired oxygen) < 300 after arrival to intensive care unit (ICU), (n = 34) were randomized to receive either PRVC or PCV. Air way pressure (Paw) and arterial blood gases (ABG) were measured at four time points [T1: After induction of anesthesia, T2: after CPB (in the ICU), T3: 1 h after intervention mode, T4: 1 h after T3]. Oxygenation index (OI) = [PaO2/ {FiO2 × mean airway pressure (Pmean)}] was calculated for each set of data and used as an indirect estimation for intrapulmonary shunt.Results:There is a steady and significant improvement in OI in both the groups at first hour [PCV, 27.5(3.6) to 43.0(7.5); PRVC, 26.7(2.8) to 47.6(8.2) (P = 0.001)] and second hour [PCV, 53.8(6.4); PRVC, 65.8(7.4) (P = 0.001)] of ventilation. However, the improvement in OI was more marked in PRVC at second hour of ventilation owing to significant low mean air way pressure compared to the PCV group [PCV, 8.6(0.8); PRVC, 7.7(0.5), P = 0.001].Conclusions:PRVC may be useful in a certain group of patients to reduce intrapulmonary shunt and improve oxygenation after cardiopulmonary bypass-induced perfusion mismatch.

Intravenous Sildenafil in the Treatment of Neonates with Persistent Pulmonary Hypertension

To evaluate the safety of intravenous (IV) sildenafil, an inhibitor of cyclic guanosine monophosphate-specific phosphodiesterase, in treating near-term and term newborns with persistent pulmonary hypertension of the newborn (PPHN). This was an open-label, dose-escalation trial in newborns with PPHN and an oxygenation index (OI) > 15. Sildenafil was delivered by continuous IV infusion for at least 48 hours and up to 7 days. Five centers enrolled a total of 36 neonates with PPHN at a mean of 34 +/- 17 hours of age; 29 of these neonates were already receiving inhaled nitric oxide (iNO). A significant improvement in OI (28.7 to 19.3; P = .0002) was observed after 4 hours of sildenafil infusion in the higher dose cohorts. Thirty-five neonates survived; 1 neonate required extracorporeal membrane oxygenation (ECMO) support. In 4 neonates, sildenafil was stopped due to adverse events. Seven neonates were enrolled before developing the need for iNO. In these neonates, OI improved significantly by 4 hours after initiation of sildenafil infusion (24.6 to 14.7; P = .009); 6 neonates completed treatment without the need for iNO or ECMO. IV sildenafil was well tolerated, and acute and sustained improvements in oxygenation were noted in those neonates who received the higher infusion doses.

Inhaled nitric oxide in the neonate

Inhaled nitric oxide (iNO) has been used to treat both term and preterm infants with respiratory failure. Term infants with persistent pulmonary hypertension, either as a primary cause or secondary to other disease processes, respond to iNO with improvement in oxygenation indices and a decreased need for extracorporeal membrane oxygenation. Infants with congenital diaphragmatic hernia are the exception to this finding, with little clinical benefit observed with iNO treatment. Although respiratory disease in preterm infants has a component of increased pulmonary vascular resistance, little benefit of iNO administration has been observed in premature infants either early in their course or later as a treatment to prevent the evolution of chronic lung disease.

Oscillation After Inhalation: High Frequency Oscillatory Ventilation in Burn Patients With the Acute Respiratory Distress Syndrome and Co-Existing Smoke Inhalation Injury

The purpose of this study was to evaluate the effectiveness of, and complications associated with High Frequency Oscillatory Ventilation (HFOV) in burn patients with the Acute Respiratory Distress Syndrome (ARDS) who have had a smoke inhalation injury, and to compare with those without an inhalation injury. Burn patients with progressive oxygenation failure from ARDS while on conventional mechanical ventilation were placed on HFOV as a "rescue" ventilation modality. There were 19 patients with burn + inhalation injury and 30 patients with burn only. Burned patients with ARDS but without inhalation injury had significant temporal improvement in the oxygenation index from 27 +/- 8 on conventional mechanical ventilation to 17 +/- 6 within 48 hours of initiating HFOV. However, burned patients with ARDS and smoke inhalation injury did not achieve significant or even eventual improvements in oxygenation index with HFOV. There was also a trend towards higher rates of early HFOV failure and severe hypercapnia while on HFOV among the patients with inhalation injury. Delivery of nebulized bronchodilators, heparin and n-acetyl cysteine, normally mainstays of smoke inhalation therapy, was impossible during HFOV. The presence of a smoke inhalation injury appears to impair the response to HFOV when this ventilation modality is instituted for ARDS-related oxygenation failure. Severe hypercapnia tended to be more frequent during HFOV among patients with smoke inhalation. These findings, combined with the difficulties in delivery of nebulized medications during HFOV suggest that HFOV may not be the optimal "rescue" ventilation modality in cases of ARDS if there has been an inhalation injury.