***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: We studied the effects of two methods of synchronized mechanical ventilation [ synchronized intermittent m and atory ventilation ( SIMV ) and assist/control ( A/C ) ] on ventilation , gas exchange , patient effort , and arterial blood pressure ( ABP ) fluctuations .  SIMV and A/C were applied in r and om order in 12 preterm neonates ( gestational age , 29.7 + /- 2.3 weeks ; birth weight , 1,217 + /- 402 g ) . We measured total ( Vetot ) and mechanical ( Vemech ) minute ventilation , spontaneous ( Vtspont ) and ventilator supported ( Vtmech ) tidal volume , transcutaneous oxygen saturation ( SpO2 ) , transcutaneous PO2 ( TcPO2 ) , and PCO2 , ( TcPCO2 ) , mean airway pressure ( Paw ) , phasic esophageal pressure deflections ( Pe ) as an estimate of inspiratory effort , mean arterial blood pressure ( ABP ) , and beat-to-beat ABP fluctuations . The measurements obtained during conventional intermittent m and atory ventilation ( IMV ) were compared with the recordings during SIMV and A/C. To make the measurement conditions comparable and to prevent hyperventilation , peak inspiratory pressure was reduced during the A/C mode so that Vetot remained in the same range as during the IMV mode . Whereas Vetot was similar in all three conditions by study design , Vemech was larger during SIMV and A/C than during IMV . Vtmech increased during SIMV and by study design was smaller during A/C than during IMV . Pe decreased during SIMV and A/C compared with IMV , and Paw was higher during A/C than during IMV or SIMV . Beat-to-beat ABP fluctuations were reduced during SIMV and A/C compared with IMV and showed a close positive correlation with Pe changes . We conclude that SIMV increases Vemech and reduces Pe compared with IMV , result ing in smaller intrathoracic and ABP fluctuations . During A/C , a substantial portion of the spontaneous respiratory effort is shifted to the ventilator , result ing in a further decrease in Pe and ABP fluctuations We set out to evaluate the impact of volume-targeted synchronized ventilation and conventional intermittent m and atory ventilation ( IMV ) on the early physiologic response to surfactant replacement therapy in neonates with respiratory distress syndrome ( RDS ) . We hypothesized that volume-targeted , patient-triggered synchronized ventilation would stabilize minute ventilation at a lower respiratory rate than that seen during volume-targeted IMV , and that synchronization would improve oxygenation and decrease variation in measured tidal volume ( V(t ) ) . This was a prospect i ve , r and omized study of 30 hospitalized neonates with RDS . Infants were r and omly assigned to volume-targeted ventilation using IMV ( n = 10 ) , synchronized IMV ( SIMV ; n = 10 ) , or assist/control ventilation ( A/C ; n = 10 ) after meeting eligibility requirements and before initial surfactant treatment . Following measurements of arterial blood gases and cardiovascular and respiratory parameters , infants received surfactant . Infants were studied for 6 hr following surfactant treatment . Infants assigned to each mode of ventilation had similar birth weight , gestational age , and Apgar scores at birth , and similar oxygenation indices at r and omization . Three patients were eliminated from final data analysis because of exclusionary conditions unknown at r and omization . Oxygenation improved significantly following surfactant therapy in all groups by 1 hr after surfactant treatment ( P < 0.05 ) . No further improvements occurred with time . Total respiratory rate was lowest ( P < 0.05 ) and variation in tidal volume ( V(t ) ) was least in the A/C group ( P < 0 . 05 ) . Minute ventilation ( V(')(E ) ) , delivered airway pressures , respiratory system mechanics , and hemodynamic parameters were similar in all groups . We conclude that volume-targeted A/C ventilation result ed in more consistent tidal volumes at lower total respiratory rates than IMV or SIMV .  Oxygenation and lung mechanics were not altered by synchronization , possibly due to the volume-targeting strategy . Of the modes studied , A/C , a fully-synchronized mode , may be the most efficient method of mechanical ventilator support in neonates receiving surfactant  for treatment of RDS The safety , efficacy , and outcome of long-term patient-triggered synchronized assisted ventilation in infants ( SAVI ) was studied in very low birthweight infants ( 450 to 1250 g ) with uncomplicated respiratory failure . Synchronization was accomplished by modified thoracic impedance technology using st and ard neonatal cardiorespiratory monitors with the output of the ventilation synchronizer triggering the exhalation solenoid of a st and ard neonatal respirator . In this nonr and omized study , the technique was found to be safe and reliable without any episodes of technical failure or adverse effects . The results indicated that in comparison with infants receiving conventional ventilation , infants receiving SAVI required ( 1 ) shorter duration of ventilation , ( 2 ) decreased duration of oxygen therapy , and ( 3 ) decreased progression of intraventricular hemorrhage to greater than or equal to grade III . Decreased duration of ventilation was statistically significant in infants weighing less than 850 g ( P less than .02 ) . These beneficial trends were ratified during a 3-year period in a total of 110 cases Purpose To compare the effectiveness of  three patient-triggered ventilators  by evaluating triggering delay time and pressure-volume loops during initiation of inspiration . Methods In a two-part study , a model lung was used in part 1 and 20 children , after tracheal intubation , in part 2 . Triggering delay time and work of breathing ( WOB ) during pressure support ventilation using three patient-triggered ventilators : Servo Ventilator 300 ™ VIP Bird ™ , and SLE 2000 Neonatal Ventilator ™ . Triggering delay time was from the beginning of negative deflection in the oesophageal pressure trace , to the onset of inspiration . The WOB was estimated directly by measuring the oesophageal pressure-volume loop . Results The Servo demonstrated superior triggering delay time and reduced WOB in the model study . The VIP Bird demonstrated shorter triggering delay and reduced WOB in the clinical component of the study . In the model lung , triggering delay time in the Servo 300 [ 62 ± 6 msec ( mean ± SD ) ] was shorter than that in the VIP Bird ( 76 ± 7 msec ) ( P < 0.05 ) , and WOB with the SLE 2000 ( 202 ± 37 g cm ) was greater than with other ventilators , ( Servo 300 , 112 ± 32 g·cm and VIP Bird 72 ± 41 g·cm ) ( P < 0.05 ) . In the clinical study , triggering delay time in the VIP Bird ( 52 ± 19 msec ) was shorter than in the other ventilators , Servo 300 ( 66 ± 14 msec ) , SLE 2000 ( 68 ± 65 msec ) ( P < 0.05 ) . The Servo 300 ( 56 ± 34 g·cm ) required higher WOB than the other ventilators : VIP Bird ( 22 ± 12 g·cm ) , SLE 2000 (l4±3g·cm)(P < 0.05 ) . Conclusion Comparative model lung performance of these ventilators does not correspond with their clinical performance . In our clinical evaluation , the VIP Bird ventilator demonstrated superior performance with shorter triggering delay time , low WOB needed to initiate inspiration , and little air leak . RésuméObjectifComparer l’efficacité de trois respirateurs déclenchés par le patient en évaluant le délai et les courbes pression-volume durant la phase initiale de l’inspiration . MéthodesDans cette étude en 2 volets , un modèle pulmonaire a été utilisé pour la première partie et 20 enfants intubés pour la deuxième . On a étudié le délai de déclenchement de l’appareil et le travail respiratoire ( TR ) durant la ventilation selon le mode pression de support en utilisant trois respirateurs déclenchés par le patient : le ventilateur Servo 300 ® , le Bird VIP ® et le SLE 2000 Neonatal Ventilator ® . Le délai de déclenchement de l’appareil a été calculé à partir du début de la défection négative sur le tracé de pression oesophagienne jusqu’au début de l’inspiration . Le TR a été estimé directement en mesurant la boucle pression-volume oesophagienne . RésultatsLe Servo a démontré un meilleur délai de déclenchement et un TR réduit dans l’étude utilisant le modèle pulmonaire . Le Bird VIP a démontré un délai plus court et un TR diminué dans la partie clinique de l’étude . Dans le modèle pulmonaire , le délai de déclenchement du Servo 300 ( 62 ± 6 msec ( moyenne + écart type ) ) a été plus court que celui du Bird VIP ( 76 ± 7 msec ) ( P < 0,05 ) , et le TR avec le SLE 2000 ( 202 ± 37 g·cm ) a été plus gr and qu’avec les deux autres ventilateurs ( Servo 300 , 112 ± 32 g·cm et Bird VIP 72 ± 41 g·cm ) ( P < 0,05 ) . Dans la partie clinique de l’étude , le délai de déclenchement du Bird VIP ( 52 ± 19 msec ) a été plus court qu’avec les autres ventilateurs , Servo 300 ( 66 ± 14 msec ) et SLE 2000 ( 68 ± 65 msec ) ( P < 0,05 ) . Le TR du Servo 300 ( 56 ± 34 g·cm ) a été plus élevé que celui des deux autres ventilateurs : Bird VIP ( 22 ± 12 g·cm ) et SLE 2000 ( 14 ± 3 g·cm ) ( P < 0,05 ) . Conclusion La performance de ces ventilateurs dans le modèle pulmonaire ne correspond pas à leur performance clinique . Au cours de notre évaluation clinique , le Bird VIP a démontré une performance supérieure aux autres avec un délai de déclenchement moindre , un faible TR pour initier l’inspiration et peu de fuites d’air Objectives To assess the importance of synchronization of mechanical ventilation with spontaneous respiratory efforts in mechanically ventilated neonates . The actions of this synchronization on ventilation , oxygenation , and BP variation were assessed . Design Prospect i ve evaluation using within-subject comparison of asynchronous and synchronous states . Setting Neonatal ICU in a large , university-affiliated hospital . Patients Fourteen neonates requiring mechanical ventilation who were initially asynchronous with the ventilator .  InterventionThe ventilator setting s were adjusted using the patients ' own inspiratory and expiratory timing to create synchronous interaction with the ventilator . Measurements and Main Results Synchrony was assessed using clinical observation combined with inspection of the air flow waveform and computerized analysis of the air flow signal to assess cycle-to-cycle reproducibility , so-called autocorrelation . Synchronous ventilation significantly improved tidal volume ( p < .05 ) , minute volume ( p < .001 ) , and all indices of the variability of arterial BP ( p < .001 ) . Mean airway pressure did not change significantly . No infant developed an air leak syndrome or intraventricular hemorrhage , which have previously been associated with asynchronous ventilation and an unstable BP , respectively . ConclusionS ynchronous ventilation can be readily applied to most ventilated neonates . It improves ventilation , and results in a marked reduction in BP variation , which may have implication s for reducing the risk of intravestricular hemorrhage . ( Crit Care Med 1993 ; 21:118–124 Objective : We tested the hypothesis that synchronization to patient effort during intermittent m and atory ventilation ( SIMV ) , when compared to conventional unsynchronized intermittent m and atory ventilation ( IMV ) , will decrease Failure of patient triggered ventilation in very premature infants may reflect the use of inappropriate triggering systems . We have therefore compared the performance of an airway and a body surface trigger in 12 infants of median gestational age 26 weeks ( range 24–27 ) .  Airway flow and oesophageal and ventilator pressure changes were recorded during two periods of patient triggered ventilation . From the traces , the degree of asynchrony ( inflation extending beyond inspiration ) , triggering rate , sensitivity ( proportion of the infant 's breaths detected ) and trigger delay ( response time ) were calculated . Although with both triggering systems there was a high rate of asynchrony , the triggering rate ( p < 0.05 ) , sensitivity ( p < 0.05 ) and trigger delay ( p < 0.01 ) were all better with the body surface trigger . These results suggest that the body surface trigger is the more appropriate system for very immature infants Asynchrony of delivered and spontaneous breaths in mechanically ventilated infants may impair gas exchange and prolong the need for assisted ventilation . We conducted a r and omized , controlled trial of a patient-triggered , flow-synchronized ventilator on 30 preterm infants with respiratory distress syndrome who weighed between 1100 and 1500 gm at birth . Entry criteria included radiographic evidence of respiratory distress syndrome and the 
    Output:
    
No disadvantage to HFPPV or triggered ventilation was noted regarding other outcomes but neither ventilatory mode was associated with a significant reduction in the incidence of chronic lung disease .
REVIEW ER 'S CONCLUSIONS Compared to conventional ventilation , benefit is demonstrated for both HFPPV and triggered ventilation with regard to a reduction in airleak and a shorter duration of ventilation respectively .