Synchronized Intermittent Mandatory Ventilation Group Research Articles

Comparison of neurally adjusted ventilatory assist and synchronized intermittent mandatory ventilation in preterm infants after patent ductus arteriosus ligation: a retrospective study

ObjectiveThis study aimed to compare the efficacy of neurally adjusted ventilatory assist (NAVA) to synchronized intermittent mandatory ventilation (SIMV) in preterm infants requiring mechanical ventilation after patent ductus arteriosus (PDA) ligation.MethodsA retrospective analysis was conducted on intubated preterm infants who underwent PDA ligation at our hospital from July 2021 to January 2023. Infants were divided into NAVA or SIMV groups based on the ventilation mode after surgery.ResultsFifty preterm infants were included. During treatment, peak inspiratory pressure (PIP) and mean airway pressure (MAP) were lower with NAVA compared to SIMV (PIP: 19.1 ± 2.9 vs. 22.4 ± 3.6 cmH2O, P < 0.001; MAP: 9.1 ± 1.8 vs. 10.9 ± 2.7 cmH2O, P = 0.002). PaO2 and PaO2/FiO2 were higher with NAVA (PaO2: 94.0 ± 11.7 vs. 84.8 ± 15.8 mmHg, P = 0.031; PaO2/FiO2: 267 [220–322] vs. 232 [186–290] mmHg, P = 0.025). Less sedation was required with NAVA (midazolam: 1.5 ± 0.5 vs. 1.1 ± 0.3 μg/kg/min, P < 0.001).ConclusionCompared to SIMV, early use of NAVA post PDA ligation in preterm infants was associated with decreased PIP and MAP. Early NAVA was also associated with reduced sedation needs and improved oxygenation. However, further studies are warranted to quantify the benefits of NAVA ventilation.

Comparison of adaptive support ventilation and synchronized intermittent mandatory ventilation in patients with acute respiratory distress syndrome: A randomized clinical trial

Background:Suitable mechanical ventilation strategies can reduce the incidence and severity of ventilator-associated lung injury in patients with acute respiratory distress syndrome (ARDS). In this study, the effects of adaptive support ventilation (ASV) and synchronized intermittent mandatory ventilation (SIMV) on respiratory parameters and arterial blood gases (ABGs) parameters were compared in ARDS patients.Materials and Methods:Twenty-four patients were randomly divided into two groups of ASV and SIMV. Patients were followed up for 3 days, and respiratory parameters including rapid shallow breathing index (RSBI), spontaneous breathing rate (SBR), minute volume, and peak inspiratory pressure (PIP) as the primary outcomes and ABG parameters including PaO2, FiO2, PaCO2, HCO3, and PaO2/FiO2 ratio as the secondary outcomes were measured.Results:PIP in patients in the SIMV group on the 1st day (P = 0.013), 2nd day (P = 0.001), and 3rd day (P = 0.004) was statistically significantly more compared to those in patients in the ASV group. RSBI, SBR, and minute volume between the ASV and SIMV groups during the 3 days were not statistically significantly different (P > 0.05). The mean arterial blood pressure, heart rate, PaO2, and PH between both groups were similar (P > 0.05). At the end of the 2nd and 3rd days, the level of FiO2 and PaCO2 in ASV was significantly lower than those in ASV group. HCO3 in each of the 3 days in the ASV group was statistically significantly lower than that in the SIMV group (P < 0.050). PaO2/FiO2 ratio in patients in the ASV group in the 3 days was statistically significantly higher than that in the SIMV group (P < 0.050).Conclusion:By reducing PIP and improving oxygenation and ABG parameters, ASV mode may be a safe and feasible mode during mechanical ventilation in patients with ARDS.

Assist Control Ventilation Versus Synchronized Mode Intermittent Mandatory Ventilation in Pediatric Intensive Care Unit

Background: Ventilator weaning consists of the gradual reduction of ventilatory support and the transfer of respiratory control and the work of breathing back to the patient, resulting in discontinuation of mechanical ventilation. Objective: The aim of this study was to compare between assisted controlled (AC) ventilation mode and synchronized intermittent mandatory ventilation (SIMV) mode for easy weaning in pediatric intensive care unit (PICU). Subjects and methods: This was non-randomized control trial; 50 patients were selected and divided alternatively into two equal groups: an AC group (ACG) and an SIMV group (SIMVG). The patients were connected on SIMV or AC mode according to inclusion and exclusion criteria and follow up of the cases was done regarding ventilator settings, compliance of the patients, need of sedation, and progress of weaning process. Results: the results revealed that there wass statistically non-significant difference between the studied groups regarding progress or weaning interruption. Larger percentage within both groups had progressive uninterrupted weaning. Conclusion: We found no evidence to support any clear-cut advantage of SIMV or AC in the acute management of respiratory failure, and we concluded that AC and SIMV could improve and fasten the weaning process and increase the success rate of weaning.

Assessment of Some Predictors of Weaning from Mechanical Ventilation in Acutely Intoxicated Patients Admitted to the Poison Control Center-Ain Shams University

Background: Respiratory failure is a common complication of poisoning with significant morbidity and mortality. Mechanical ventilation is life saving. Weaning is the process of liberating patient from mechanical ventilatory support. Interleukin-6 (IL-6) and C-reactive protein (CRP) are inflammatory mediators, released in response to many stressful conditions as weaning from mechanical ventilation. Aim of the work: The aim of the study was to assess the role of serum (IL6) level and (CRP) as predictors of outcome of weaning from mechanical ventilation in acutely intoxicated patients admitted to the Poison Control Center– Ain Shams University Hospitals (PCC-ASUHs). And to assess their role in selection of the most appropriate mode for weaning by comparing weaning by pressure support ventilation (PSV) mode, synchronized intermittent mandatory ventilation (SIMV) mode and weaning by the once-daily trial of spontaneous breathing trial by using (T-piece). Patients and Methods: The study included 58 acutely intoxicated patients, intubated and mechanically ventilated, admitted to the Intensive Care Unit (ICU) of PCC-ASUHs during the period from May 2016 till September 2018. Patients were categorized consecutively according to the outcome of the 2-hour of spontaneous breathing trial (SBT) into 2 groups: Group I (The SBT Success group): included 19 patients who succeed spontaneous breathing trial. Group II (The SBT failed group): included 39 patients who failed SBT which was further subdivided into 3 groups according to the method of weaning: group (1) PSV group, group (2) SIMV group and group (3) Once T-piece group, each group including 13 patients. Results: IL-6 was significantly increased after 2 days in patients who failed the SBT compared to the success group, while CRP was significantly higher in the failed group during weaning trial and 2 days after. There is no significant difference between the three weaning modes regarding IL6 and CRP. Conclusion: Patients who failed the SBT presented higher inflammatory parameters than those who passed. CRP could predict the outcome of weaning from mechanical ventilation.

Clinical Study of High Frequency Oscillatory Ventilation on Neonatal Respiratory Distress Syndrome

To investigate the clinical effect of high frequency oscillatory ventilation (HFOV) in neonatal respiratory distress syndrome (NRDS). Forty-six children with NRDS who were treated in Neonatal Intensive Care Unit (NICU) from January 2015 to December 2016 were selected as study subjects, 34 in study group (HFOV) and 12 in control group (SIMV), both groups were given basic and PS treatment, blood gas analysis and clinical treatment before and after treatment were compared indicators. Compared with SIMV group, HFOV group had faster blood gas analysis and treatment and fewer complications. HFOV and PS combined treatment of neonatal respiratory distress syndrome obvious effect, high safety, worthy of clinical promotion and use.

Comparing the effects of adaptive support ventilation and synchronized intermittent mandatory ventilation on intubation duration and hospital stay after coronary artery bypass graft surgery.

Background:Different modes of mechanical ventilation are used for respiratory support after coronary artery bypass graft (CABG). This study aimed to compare the effect(s) of using adaptive support ventilation (ASV) and synchronized intermittent mandatory ventilation (SIMV) on the length of mechanical ventilation (intubation duration) and hospital stay after coronary artery bypass graft surgery.Materials and Methods:In a randomized control trial, 64 patients were ventilated with ASV as the experiment group or with SIMV as the control group after CABG surgery in Chamran Hospital of Isfahan University of Medical Sciences. The time of tracheal intubation and the length of hospital stay were compared between the two groups. Data were analyzed and described using statistical analysis (independent t-test).Results:The mean time of intubation duration was significantly lower in ASV group compared with SIMV group. (4.83 h vs 6.71 h, P < 0.001). The lengths of hospital stay in the ASV and the SIMV groups were 140.6 h and 145.1 h, respectively. This difference was significant between the two groups (P = 0.006).Conclusions:According to the results of this study, using ASV mode for mechanical ventilation after CABG led to a decrease in intubation duration and also hospital stay in comparison with the SIMV group. It is recommended to use ASV mode on ventilators for respiratory support of patients undergoing coronary artery bypass graft surgery.

Pressure regulated volume controlled ventilation versus synchronized intermittent mandatory ventilation in COPD patients suffering from acute respiratory failure

BackgroundVolume controlled ventilation (VC) allows a set tidal volume to be guaranteed but it causes excessive airway pressures that may lead to barotrauma. Pressure controlled ventilation (PC) limits ventilator-induced lung injury but has a disadvantage of variable tidal volume delivery. Pressure-regulated volume controlled ventilation is a kind of dual-control ventilation that combines the advantages of both volume controlled and pressure controlled ventilation. ObjectiveTo compare the pressure regulated volume controlled ventilation (PRVC) versus traditional synchronized intermittent mandatory ventilation (SIMV) in chronic obstructive pulmonary disease (COPD) patients suffering from acute respiratory failure. Patients and methodsThis prospective study was carried on 30 COPD patients suffering from acute respiratory failure, divided in two groups: group 1 patients were ventilated using the SIMV mode and group 2 patients were ventilated using the PRVC mode. The arterial blood gas (ABG) parameters, ventilation data, complications and prognosis were compared in the two groups. ResultsThe ABG parameters improved better in the PRVC group after 6 and 48h. The peak inspiratory pressure (PIP) values were lower in the PRVC group. There were fewer complications (33% in group 2 versus 86% in group 1). The prognosis was better in PRVC group as 13 patients (86%) were weaned, 1 patient (7%) died and 1 patient (7%) failed to be weaned. On the other hand, 6 patients (40%) were weaned, 3 patients (20%) died and 6 patients (40%) failed to be weaned in the SIMV group. ConclusionThe PRVC mode is better than the volume controlled SIMV mode in ventilating COPD patients with acute exacerbations and type II respiratory failure.

Evaluation of some predictors for successful weaning from mechanical ventilation

IntroductionMost international weaning researchers have attempted to find better indexes or parameters which can predict the weaning outcome in the best possible way.Our research attempts to confirm and find better weaning indexes and parameters. Aim of the workThe aim of this study is to compare between the efficacy of some predictors in different weaning modes for successful weaning from mechanical ventilation. MethodThe study was carried out on 100 (70 males, 30 females) patients receiving mechanical ventilation, due to respiratory and non respiratory causes. Patients were divided into 4 groups according to the method of weaning: group (1) CPAP (n=25), group (2) PSV (n=25), group (3) SIMV (n=25) and group (4) NPPV (n=25). We used a 3 step protocol for weaning according to Cleveland Clinical Journal of Medicine. The following assessments were carried out on admission, during MV (before weaning) and during weaning: PaCO2, pH, PaO2, RSBI (Rapid shallow breathing index), CROP index, The CORE index, integrative weaning index (IWI). ResultsThis study shows that the highest successes rate is in the NPPV group (92%) while the highest failure rate is in the SIMV group (36%). It also shows that there is non significant difference between the studied groups regarding PaO2, PaCo2 and PH before starting weaning (P value>.05). After starting weaning the highest value of PaO2, PaCO2, and PH was in the NIPPV group and the lowest value was in the SIMV group. There is highly significant difference (P value<0.001) between patients who succeeded and who failed weaning as regards CORE index and only significant difference regarding RSBI, while there is non significant difference as regards other indices(CROP, IWI). ConclusionABG and RSBI can be used as good weaning predictors and the CORE index is better in predicting the weaning outcome than the CROP index, the IWI and the RSBI as their value is better in the NPPV group which expresses the highest success rate.

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Background and aims: Mechanical ventilation (MV) can induce oxidative stres. Ischemia-modified albumin (IMA) is a new biomarker for the identification of myocardial ischemia. This study is aimed to investigate IMA production by induced oxidative stress during MV in newborns. Methods: This cross-sectional study was performed between September 2012 and June 2012. Seventeen newborns ventilated with SIMV (SIMV-group) and 20 ventilated with CPAP (CPAP-group) were included the study. Two blood samples were obtained from each newborns (one of them during ventilation and the second sample after cessation of ventilation). Total antioxidant capacity (TAC) and total oxidant status (TOS) were measured using Erel’s methods. IMA measured with ELISA kit (Cusabiso®). Oxidant stress index (OSI) was calculated. Statistical analyses were performed by using SPSS v.18.0. IRB approvall was taken. Results: No significant differences were found between SIMV and CPAP groups in mean gestation age and birth weight. IMA, TOS and OSI levels were significantly elevated during ventilation support (The mean 102.2 ± 9.3 IU/mL, 15.5 ± 1.3 µmolH2O2equivalent/L, and 0.85 ± 0.22 arbitrary unit [ABU], respectively), while decreased after cessation of ventilation support (the mean 82.9 ± 11.9 IU/mL, 13.4 ± 1.3 µmolH2O2equivalent/L, and 0.64 ± 0.14 ABU, respectively, p=0.001) for the entire study group. TAC was significantly decreased during ventilation support while eleveted after cessation of ventilation support for the entire study group. Conclusions: With respect to the mean TAC, OSI and IMA levels, no significant differences were observed between SIMV and CPAP groups. Further prospective studies are needed to compare the effect of different ventilation modes on oxidative stress and IMA levels.

Effects of adaptive support ventilation and synchronized intermittent mandatory ventilation on peripheral circulation and blood gas markers of COPD patients with respiratory failure.

The objective of the study was to investigate the effects of adaptive support ventilation (ASV) and synchronized intermittent mandatory ventilation (SIMV) on peripheral circulation of chronic obstructive pulmonary disease (COPD) patients with respiratory failure. 86 COPD patients with respiratory failure were recruited in this study. Self-control method was used to compare the effect of ASV and SIMV on the parameters of ventilation machine, heart rate, blood pressure, central venous pressure (CVP), and blood gas markers. When the patients in ASV and SIMV groups were compared, respiratory rate, tidal volume, and peak airway pressure (PIP) showed significant difference. When minute ventilation (MV) was compared, no significant difference was shown. When peripheral circulation parameters were compared, peripheral circulation heart rate, SBP, DBP, and CVP showed significant difference. Compared with SIMV group, PaO2, pH, and SaO2 values were remarkably increased (P < 0.01) while no significant difference was found for partial pressure of carbon dioxide (pCO2) when two groups were compared. In conclusion, when mechanical ventilation was used in COPD patients with respiratory failure, ASV can significantly improve clinical outcomes.

The effect of simvastatin and erythropoietin on renal fibrosis in rats with unilateral ureteral obstruction

Prevention of fibrosis is a very important therapeutic strategy in the treatment of obstructive nephropathy (ON). The aim of this study is to show and compare the actions of Simvastatin (Simv) and Erythropoietin (Epo) in renal expression of nuclear factor kappa B (NFκB), transforming growth factor-β (TGF-β), basic fibroblast growth factor (bFGF), platelet-derived growth factor B (PDGF-B), fibronectin and development of interstitial fibrosis in rats with unilateral ureteral obstruction (UUO). A total of 48 Sprague–Dawley rats were allocated to 4 groups of sham, Epo, Simv and control. Unilateral ureteral ligation was performed on all rats except the Sham group. For interstitial fibrosis Masson’s trichrome stain and for the expression of TGF-β, PDGF-B, bFGF, NFκB and fibronectin, immunohistochemical methods were used. In the Epo and Simv groups, expression of TGF-β and fibronectin and staining with Masson’s trichrome were less compared to the control group. In addition, fibronectin expression in the Epo group was less than the Simv group. Unlike the Simv group, NFκB and bFGF expression in the Epo group were less when compared to the control group. Consequently, it was seen that both Epo and Simv prevented fibrosis in ON. Epo was superior in this effect by suppressing the expressions of NFκB and bFGF more effectively than Simv. Based on this finding, Epo might be a better agent than Simv in the prevention of fibrosis in ON.

High frequency oscillatory ventilation versus synchronized intermittent mandatory ventilation in preterm neonates with hyaline membrane disease: A randomized controlled trial

This randomized controlled study was conducted to compare the efficacy and safety of High frequency oscillatory ventilation (HFOV) and Synchronized intermittent mandatory ventilation (SIMV) in preterm neonates with hyaline membrane disease requiring ventilation. The ventilation strategy in both the groups included achieving optimal lung recruitment and targeted blood gases. 49 patients received HFOV and 61 SIMV. The baseline characteristics were similar in both the groups. HFOV group demonstrated better early oxygenation, enabled reduction in oxygenation index (OI) within 24 h of ventilation (difference in mean OI at 1, 6, and 24 h of ventilation: P=0.004 in HFOV, and 0.271 in SIMV group). Duration of hospital stay was shorter in HFOV group (P=0.003). The complication rate and survival were similar in two groups.

Noninvasive proportional assist ventilation may be useful in weaning patients who failed spontaneous breathing trial

BackgroundEndotracheal mechanical ventilation (ETMV) is accompanied with a high morbidity and mortality in intensive care unit (ICU) patients. The aim of this prospective randomized controlled study was to evaluate the effectiveness of noninvasive proportional assist ventilation (PAV) as a method of weaning in patients who could not tolerate spontaneous breathing trial (SBT).Patients and methodsAmong 112 patients presented with acute respiratory failure (ARF) admitted to Zagazig university surgical ICU, 42 patients of them failed a 2 h-SBT after they met simple criteria for weaning. Conventional invasive synchronized intermittent mandatory ventilation (SIMV) was used as the control weaning technique in 21 patients (SIMV group), and noninvasive PAV was applied immediately after extubation in the remaining 21 patients (PAV group).ResultsThere was no significant difference regarding the main clinical, functional characteristics, and the physiologic parameters of the two weaning groups at the time of their admission. Gas exchange at 1-h post-randomisation was significantly improved in both groups. The duration of ventilatory support was significantly shorter in the PAV group (12.8 + 8.3 days vs 22.3 + 13.3 days in the conventional group; P < 0.05). Weaning success was significantly higher in the PAV group (18 patients“85%” vs 11 patients “52 %” in the conventional group P < 0.05). ICU survival was higher, while, reintubation rate was lower in PAV (three patients “14%” vs 10 patients “47%” in the conventional group; P < 0.05). The rate of tracheostomy was significantly lower in the PAV group (one patient “4%” vs seven patients “33%” in the conventional group; P < 0.05). The incidence of VAP was higher in the conventional group (eight patients “38%” vs one patient “4%”in the PAV group; P < 0.05).ConclusionNoninvasive PAV could be considered as an effective and safe method of weaning in patients who cannot tolerate 2 h-SBT.

Cholesterol-lowering strategies reduce vascular LRP1 overexpression induced by hypercholesterolaemia

Low density lipoprotein receptor-related protein (LRP1) plays a key role on vascular functionality and is upregulated by hypercholesterolemia and hypertension. To investigate the effect of cholesterol-lowering interventions on vascular LRP1 over expression and whether simvastatin influences LRP1 expression. Male New Zealand rabbits were recruited into various groups, one group was fed a normal chow diet for 28 days (control group, n = 6), other group (n = 24) was fed a hypercholesterolemic diet (HC), six rabbits were euthanized at day 28 to test the capacity of HC diet to induce early atherosclerosis and the rest at day 60 (n = 18) after receiving either HC diet (HC group, n = 6), HC diet with simvastatin (2·5 mg/kg.day) (HC+simv group, n = 6), or a normal chow diet (NC group, n = 6) for the last 32 days. High-cholesterol diet raised vascular LRP1 concomitantly with increased lipid, VSMC and macrophage content in the arterial intima. Simvastatin and return to normocholesterolemic diet significantly reduced systemic cholesterol levels and vascular lipid content. Interestingly, these interventions also downregulate LRP1 overexpression in the vascular wall although to a different extent (HC+simv: 75 ± 3·6%vs NC: 50 ± 3·5% versus, P = 0·002). Immunohistochemistry studies showed that LRP1 diminushion was associated to a reduction in the number of intimal VSMC in HC+simv.group. Simvastatin per se did not exert any significant effect on LRP1 expression in rabbit aortic smooth muscle cells (rSMC). Our results demonstrate that cholesterol-lowering interventions exerted down regulatory effects on vascular LRP1 over expression induced by hypercholesterolemia and that simvastatin did not influence LRP1 expression beyond its cholesterol-lowering effects.

Comparable effect of conventional ventilation versus early high-frequency oscillation on serum CC16 and IL-6 levels in preterm neonates

Clara cell 16 kD protein (CC16) and interleukin (IL)-6 have been used as peripheral blood biomarkers of alveolar leakage and inflammation, respectively. Thus, their measurement in the bloodstream could be used to assess ventilator-induced lung injury. The objective of this study was to evaluate the effect of optimized synchronized intermittent mandatory ventilation (SIMV) and high-frequency oscillatory ventilation (HFOV) on circulating CC16 and IL-6 levels when used as the initial ventilation modes in preterm neonates. Single center, prospective, randomized clinical study in preterm neonates (gestational age 30 weeks) requiring mechanical ventilation within the first 2 h of life. Serum CC16 and IL-6 were measured on establishment of the assigned ventilation mode after admission, at days 3 and 14 of life as well as at 36 weeks postmenstrual age. Demographic-perinatal data and clinical parameters were also recorded. Of the 30 neonates studied, 24 (gestational age 27.1±1.7 weeks, birth weight 942±214 g) were finally analyzed, equally assigned into the SIMV and HFOV groups. Both groups had comparable demographic-perinatal characteristics and clinical parameters. Serum CC16 and IL-6 altered significantly over time (repeated-measures analysis of variance, both P<0.001). However, changes were not affected by the ventilation mode. Post hoc analysis showed a significant decrease in CC16 and IL-6 from birth up to 36 weeks postmenstrual age in both groups. In preterm neonates, SIMV and HFOV are associated with comparable circulating CC16 and IL-6 levels. These findings suggest a similar alveolar leakage and systemic inflammation with any of the ventilation modes evaluated when their usage is optimized.

Comparative study on effects of volume-controlled ventilation and pressure-limited ventilation for neonatal respiratory distress syndrome

Purpose : In contrast with traditional time-cycled, pressure-limited ventilation, during volume-controlled ventilation, a nearly constant tidal volume is delivered with reducing volutrauma and the episodes of hypoxemia. The aim of this study was to compare the efficacy of pressure-regulated, volume controlled ventilation (PRVC) to Synchronized intermittent mandatory ventilation (SIMV) in VLBW infants with respiratory distress syndrome (RDS).Methods : 34 very low birth weight (VLBW) infants who had RDS were randomized to receive either PRVC or SIMV with surfactant administration : PRVC group (n=14) and SIMV group (n=20). We compared peak inspiratory pressure (PIP), duration of mechanical ventilation, and complications associated with ventilation, respectively with medical records. Results : There were no statistical differences in clinical characteristics between the groups. After surfactant administration, PIP was significantly lower during PRVC ventilation for 48hrs and accumulatevive value of decreased PIP was higher during PRVC ventilation for 24hrs (P

The Effects of Ventilatory Mode on Lung Aeration Assessed With Computer Tomography: A Randomized Controlled Study

Maintenance of spontaneous breathing superimposed on mechanical ventilation is suggested to improve gas exchange in patients with acute lung injury. The aim of this study was to evaluate the long-term effects of airway pressure release ventilation with maintained unsupported spontaneous breathing (APRV) and synchronized intermittent mandatory ventilation with pressure support (SIMV) on the amount of lung collapse in acute lung injury patients. Thirty-seven patients with acute lung injury were studied in a trial comparing APRV or SIMV. Computer-assisted tomography scannings (CT) were performed before randomization and at day 7. The change in the amount of nonaerated lung was comparable between groups; 14.7% (3.8-17.4) in APRV group (n = 13) and 9.6% (-1.4 to 18.62) in the SIMV group (n = 10), (P = .65, difference in mean 4.9%, 95% confidence interval -9.0% to 19.0%). The effects of APRV and SIMV on lung aeration are similar after 7 days of mechanical ventilation.

Gas exchange and lung inflammation using nasal intermittent positive-pressure ventilation versus synchronized intermittent mandatory ventilation in piglets with saline lavage-induced lung injury: An observational study*

Physiologic and pathologic comparison of two modes of assisted ventilation, nasal intermittent positive-pressure ventilation (NIPPV) and synchronized intermittent mandatory ventilation (SIMV), in spontaneously breathing term newborn piglets with saline lavage-induced lung injury. After inducing acute lung injury via repetitive saline lavage, piglets were randomized to NIPPV (n = 12) or SIMV (n = 11) and treated for 6 hrs. Clinical laboratory. Spontaneously breathing term newborn piglets. Invasive (SIMV) or noninvasive (NIPPV) assisted ventilation for 6 hrs. Physiologic parameters and arterial blood gases were continuously monitored. At the conclusion of the study, lung tissue was obtained to analyze for evidence of inflammation, including myeloperoxidase, interleukin-8, and hydrogen peroxide levels, as well as for evidence of pathologic injury. Piglets treated with NIPPV demonstrated higher arterial blood gas pH (p < .001), lower PaCO2 (p < .05), and a lower set respiratory rate (p < .0001) as compared with the SIMV-treated piglets. The piglets in the SIMV group had higher PaO2/PaO2 ratio than those in the NIPPV group (p = .001). There was significantly more interstitial inflammation (p = .04) in the SIMV-treated piglets compared with the NIPPV-treated piglets. Total respiratory rate, heart rate, blood pressure, oxygen saturation, and biochemical markers of lung inflammation were not different between the groups. In surfactant-deficient term newborn piglets, NIPPV offers an effective and noninvasive ventilatory strategy with the potential for less pathologic lung inflammation.

Pressure-Regulated Volume Control Ventilation vs Synchronized Intermittent Mandatory Ventilation for Very Low-Birth-Weight Infants

To test the hypothesis that pressure-regulated volume control (PRVC), an assist/control mode of ventilation, would increase the proportion of very low-birth-weight infants who were alive and extubated at 14 days of age as compared with synchronized intermittent mandatory ventilation (SIMV). Ventilated infants with birth weight of 500 to 1249 g were randomized at less than 6 hours of age either to pressure-limited SIMV or to PRVC on the Servo 300 ventilator (Siemens Electromedical Group, Danvers, Mass). Infants received their assigned mode of ventilation until extubation, death, or meeting predetermined failure criteria. Mean +/- SD birth weights were similar in the SIMV (888 +/- 199 g, n = 108) and PRVC (884 +/- 203 g, n = 104) groups. No differences were detected between SIMV and PRVC groups in the proportion of infants alive and extubated at 14 days (41% vs 37%, respectively), length of mechanical ventilation in survivors (median, 24 days vs 33 days, respectively), or the proportion of infants alive without a supplemental oxygen requirement at 36 weeks' postmenstrual age (57% vs 63%, respectively). More infants receiving SIMV (33%) failed their assigned ventilator mode than did infants receiving PRVC (20%). Including failure as an adverse outcome did not alter the overall outcome (39% of infants in the SIMV group vs 35% of infants in the PRVC group were alive, extubated, and had not failed at 14 days). In mechanically ventilated infants with birth weights of 500 to 1249 g, using PRVC ventilation from birth did not alter time to extubation.

Is there an Advantage of Using Pressure Support Ventilation with Volume Guarantee in the Initial Management of Premature Infants with Respiratory Distress Syndrome? A pilot study

To evaluate the feasibility of using the pressure support ventilation with volume guarantee (PSV-VG) as an initial ventilatory mode in preterm infants with respiratory distress syndrome (RDS) after surfactant treatment to achieve accelerated weaning of peak inspiratory pressure (PIP) and mean airway pressure (MAP). Initial 24-hour ventilatory parameters were compared in two groups of preterm infants managed by PSV-VG and the synchronized intermittent mandatory ventilation (SIMV) mode in a randomized controlled pilot study after surfactant treatment for RDS. A total of 16 babies were randomized to PSV-VG (1198+/-108 g [mean+/-SEM]; 27.9+/-0.6 weeks) and 18 babies to SIMV (birth weight 1055+/-77 g; gestational age 27.4+/-0.5 weeks). Repeated measures analysis of variance was used to compare serial values of PIP and MAP in the two groups. The PIP and MAP decreased over time (p<0.001) during the first 24 hours after surfactant administration in both groups but the decrease in MAP was faster in the SIMV group compared to PSV-VG group (p=0.035). The median numbers of blood gases during the first 24 hours were four and two in the SIMV and PSV-VG groups, respectively (p<0.001). The overall outcomes were not significantly different between the two groups. PSV-VG did not offer any ventilatory advantage over SIMV in the initial management of surfactant-treated premature newborns with RDS except for minimizing the number of blood gases.