Intermittent Mandatory Ventilation Research Articles

Effects of noninvasive proportional assist vs pressure support ventilation on respiratory work in chronic obstructive pulmonary disease patients with hypercapnia

Objective: To investigate the effect of noninvasive proportional assist ventilation (PAV) on respiratory work in chronic obstructive pulmonary disease(COPD) patients, in comparison to noninvasive pressure support ventilation(PSV). Methods: Ten severe COPD patients with hypercapnia during acute exacerbation were examined. The baseline inspiratory pressure of PSV (PS) and the assistance level of PAV(PA) were titrated by patients' tolerance. In addition to the baseline PS and PA, an additional decrease by 25% (PS-=75% PS, PA-=75% PA) or increase by 25% (PS+ =125% PS, PA+ =125% PA) of the assist level were applied to the patients. After the assessment of unassisted spontaneous breathing (SB), the patient was placed on the 6 levels of noninvasive-PSV and noninvasive-PAV in random sequence. Each level lasted at least 20 minutes. Respiratory rate (RR), tidal volume (Vt), and respiratory work(Wex, Wip and Wv) were measured. Asynchrony index (AI) was calculated. Results: During ventilation, Vt was significantly higher with each assist level than with SB. The Vt was significant increased with PS+ than with PA+ . An increase in expiratory work(Wex) and decrease in inspiratory work(Wip) were observed respectively, with the increasing assist level. The inspiratory muscles assessed by Wip were more unloaded at PS compared with PA [PS: (1.59±1.27) J/min vs PA: (4.99±3.48) J/min P<0.01]. However, the Wex was significantly higher with PS+ than with PA+ [PS+ : (1.17±0.54) J/min vs PA+ : (0.49±0.56)J/min, P<0.01]. The AI was increased with the increasing assist level of PSV [PS-: (0.46±0.57)%, PS: (1.36±1.24)% PS+ : (5.26±4.77)]. No asynchrony events were observed at PA- and PA. "Runaway" (expiratory asynchrony) was observed during PA+ [AI: (2.62±2.72)%]. Conclusions: Noninvasive-PAV can increase the Vt and decrease the Wip of the COPD patients with hypercapnia and avoid the over-assistance. The "Runaway" will occur at assist level higher than that set by tolerance. Physiological data can monitor the patient's responses and the ventilator-patient interaction, which may provide objective criteria for ventilator setting.

Can proportional ventilation modes facilitate exercise in critically ill patients? A physiological cross-over study

BackgroundEarly exercise of critically ill patients may have beneficial effects on muscle strength, mass and systemic inflammation. During pressure support ventilation (PSV), a mismatch between demand and assist could increase work of breathing and limit exercise. A better exercise tolerance is possible with a proportional mode of ventilation (Proportional Assist Ventilation, PAV+ and Neurally Adjusted Ventilatory Assist, NAVA). We examined whether, in critically ill patients, PSV and proportional ventilation have different effects on respiratory muscles unloading and work efficiency during exercise.MethodsProspective pilot randomized cross-over study performed in a medico-surgical ICU. Patients requiring mechanical ventilation >48 h were enrolled. At initiation, the patients underwent an incremental workload test on a cycloergometer to determine the maximum level capacity. The next day, 2 15-min exercise, at 60% of the maximum capacity, were performed while patients were randomly ventilated with PSV and PAV+ or NAVA. The change in oxygen consumption (ΔVO2, indirect calorimetry) and the work efficiency (ratio of ΔVO2 per mean power) were computed.ResultsTen patients were examined, 6 ventilated with PSV/PAV+ and 4 with PSV/NAVA. Despite the same mean inspiratory pressure at baseline between the modes, baseline VO2 (median, IQR) was higher during proportional ventilation (301 ml/min, 270–342) compared to PSV (249 ml/min, 206–353). Exercise with PSV was associated with a significant increase in VO2 (ΔVO2, median, IQR) (77.6 ml/min, 59.9–96.5), while VO2 did not significantly change during exercise with proportional modes (46.3 ml/min, 5.7–63.7, p < 0.05). As a result, exercise with proportional modes was associated with a better work efficiency than with PSV. The ventilator modes did not affect patient’s dyspnea, limb fatigue, distance, hemodynamics and breathing pattern.ConclusionsProportional ventilation during exercise results in higher work efficiency and less increase in VO2 compared to ventilation with PSV. These preliminary findings suggest that proportional ventilation could enhance the training effect and facilitate rehabilitation.

Adaptive Support Ventilation Reduces the Incidence of Atelectasis in Patients Undergoing Coronary Artery Bypass Grafting: A Randomized Clinical Trial.

BackgroundPulmonary complications are common following cardiac surgery and can lead to increased morbidity, mortality, and healthcare costs. Atelectasis is the most common respiratory complication following cardiac surgery. One of the most important methods for reducing pulmonary complications is supportive care with protective ventilation strategies. In this study, we aimed to assess the effect of adaptive support ventilation (ASV) on atelectasis in patients undergoing cardiac surgery.MethodsIn this single-blind randomized clinical trial, 115 patients, undergoing coronary artery bypass grafting, were randomly allocated into 2 groups: 57 patients in the intervention and 58 patients in the control group. Patients in the intervention group were weaned with ASV, while patients in the control group were managed using synchronized intermittent mandatory ventilation (SIMV) and pressure support. The incidence of atelectasis, duration of mechanical ventilation, manual ventilator setting, arterial blood gas measurements, and length of hospital stay were compared between the groups.ResultsThe incidence of atelectasis, number of changes in the manual ventilator setting, number of alarms, and length of hospital stay reduced in the intervention group. However, duration of mechanical ventilation and number of ABG measurements were not significantly different between the groups.ConclusionsThe ASV mode could reduce the incidence of atelectasis and length of hospital stay. However, it did not reduce the duration of mechanical ventilation. It seems that ASV is not a superior mode for faster extubation.

Comparison of Effort of Breathing for Infants on Nasal Modes of Respiratory Support

To directly compare effort of breathing between high flow nasal cannula (HFNC), nasal intermittent mechanical ventilation (NIMV), and nasal continuous positive airway pressure (NCPAP). This was a single center prospective cross-over study for patients <6 months in the cardiothoracic or pediatric intensive care unit receiving nasal noninvasive respiratory support after extubation. We measured effort of breathing using esophageal manometry with pressure-rate product (PRP) on all 3 modes. NIMV synchrony was determined by comparing patient efforts (esophageal manometry) with mechanically delivered breaths (spirometry in ventilator circuit). On NIMV, PRP and synchrony was also measured after adding a nasal clip on 26 patients. Forty-two children were included. Median (IQR) age was 2 (0.5, 4) months. There was no difference in median PRP between HFNC 6 liters per minute, 355 (270,550), NIMV 12/5 cm H2O, 341 (235, 472), and NCPAP 5 cm H2O, 340 (245,506) (P?=?.33). Results were similar regardless of HFNC flow rate or NIMV inspiratory pressure. Median PRP on CPAP of 5 cm H2O prior to extubation 255 (176, 375) was significantly lower than all postextubation values (P?<?.002). On NIMV, less than 50% of patient efforts resulted in a ventilator breath, which was not improved with a nasal clip (P?>?.07)). However, as NIMV synchrony improved (>60%), PRP on NIMV was lower than on HFNC. For infants, effort of breathing is similar on HFNC, NIMV, and NCPAP after extubation, regardless of flow rate or inspiratory pressure. We speculate that bi-level NIMV may be superior if high levels of synchrony can be achieved.

Automated Weaning from Mechanical Ventilation after Off-Pump Coronary Artery Bypass Grafting.

The discontinuation of mechanical ventilation after coronary surgery may prolong and significantly increase the load on intensive care unit personnel. We hypothesized that automated mode using INTELLiVENT-ASV can decrease duration of postoperative mechanical ventilation, reduce workload on medical staff, and provide safe ventilation after off-pump coronary artery bypass grafting (OPCAB). The primary endpoint of our study was to assess the duration of postoperative mechanical ventilation during different modes of weaning from respiratory support (RS) after OPCAB. The secondary endpoint was to assess safety of the automated weaning mode and the number of manual interventions to the ventilator settings during the weaning process in comparison with the protocolized weaning mode. Forty adult patients undergoing elective OPCAB were enrolled into a prospective single-center study. Patients were randomized into two groups: automated weaning (n = 20) using INTELLiVENT-ASV mode with quick-wean option; and protocolized weaning (n = 20), using conventional synchronized intermittent mandatory ventilation (SIMV) + pressure support (PS) mode. We assessed the duration of postoperative ventilation, incidence and duration of unacceptable RS, and the load on medical staff. We also performed the retrospective analysis of 102 patients (standard weaning) who were weaned from ventilator with SIMV + PS mode based on physician's experience without prearranged algorithm. Realization of the automated weaning protocol required change in respiratory settings in 2 patients vs. 7 (5-9) adjustments per patient in the protocolized weaning group. Both incidence and duration of unacceptable RS were reduced significantly by means of the automated weaning approach. The FiO2 during spontaneous breathing trials was significantly lower in the automated weaning group: 30 (30-35) vs. 40 (40-45) % in the protocolized weaning group (p < 0.01). The average time until tracheal extubation did not differ in the automated weaning and the protocolized weaning groups: 193 (115-309) and 197 (158-253) min, respectively, but increased to 290 (210-411) min in the standard weaning group. The automated weaning system after off-pump coronary surgery might provide postoperative ventilation in a more protective way, reduces the workload on medical staff, and does not prolong the duration of weaning from ventilator. The use of automated or protocolized weaning can reduce the duration of postoperative mechanical ventilation in comparison with non-protocolized weaning based on the physician's decision.

Proportional Assist Ventilation: More than Just another Mode

Proportional Assist Ventilation: More than Just another Mode

Prevalence and predictors of intra-abdominal hypertension and compartment syndrome in surgical patients in critical care units at Kenyatta National Hospital.

BackgroundIntra-abdominal hypertension (IAH) affects almost every organ sytem.If it is not detected early and corrected, mortality would be high. The prevalence of IAH and abdominal compartment syndrome (ACS) at Kenyatta National Hospital (KNH) critical care units is not known. The aim of this sudy was to determine the prevalence and factors associated with development of IAH/ACS among critically ill surgical patients.MethodsThis was a cross sectional descriptive study involving surgical patients in critical care units at KNH, carried out from March 2015 to October 2015.One hundred and thirteen critically ill and ventilated patients 13 years or older were recruited into the study.Krohn’s intravesical method was used to measure intra- abdominal pressure (IAP). Measurements were done at first contact, then at 12 and 24 h. Additional parameters recorded included: laboratory tests such as serum bilirubin and total blood count as well as clinical parameters such as urine output, vital signs and peak airway pressure, among others.Frequency, means and standard deviation were used to describe the data. Categorical variables e.g. age, were analysed using Chi square test and continous variables using student ‘t’ test and Mann Whitney test as appropriateResultA total of 113 consecutive surgical patients admitted to the critical care units were recruited. Of our study population, 71.7% (by IAP max) and 67.3% (by IAP mean) had IAH. Abdominal compartment syndrome (ACS) developed in 4.4% of the population. The following factors were significant determinants of risk of IAH : amount of IV fluids over 24 h (3949.6 vs 2931.1, p = 0.003, adjusted OR 1.0 [1.0-1.002]), haemoglobin values at admission (9.9 vs 12.0, p = <0.012, adjusted OR 0.6 [0.4-0.9]), peak airway pressure (28.4 vs 17.3; p = 0.018, adjusted OR 1.6 [1.1-2.4]) and synchronised intermittent mandatory ventilation (SIMV) (60 vs 32; p = 0.041, adjusted OR 1.4 [0.78-2.04]).Of those who had IAH; age, amount of iv fluids over 24 h, fluid balance and ventilator mode were significant determinants of risk of progression to ACS .ConclusionThe prevalence of intraabdominal hypertension and abdominal compartment syndrome at KNH is high. Clinical parameters pertaining to fluids administration and ventilator mode are siginificant determinants.Electronic supplementary materialThe online version of this article (doi:10.1186/s12873-017-0120-y) contains supplementary material, which is available to authorized users.

Neurally Adjusted Ventilatory Assist in Preterm Infants With Established or Evolving Bronchopulmonary Dysplasia on High-Intensity Mechanical Ventilatory Support: A Single-Center Experience.

The aim of the present study was to report possible improvements in ventilator variables associated with a transition from synchronized intermittent mandatory ventilation to neurally adjusted ventilatory assist in preterm infants with bronchopulmonary dysplasia who required a high level of mechanical ventilatory support in a single center. Retrospective study. Neonatal ICU. Twenty-nine preterm infants with a median gestational age of 25.4 weeks (range, 23.4-30.3 wk) and a median birth weight of 680 g (range, 370-1,230 g) and who were supported with a mechanical ventilator for more than 4 weeks and had a respiratory severity score greater than four during conventional mechanical ventilation prior to conversion to neurally adjusted ventilatory assist. Comparison of ventilatory variables, work of breathing, and blood gas values during conventional ventilation and at various time intervals after the change to neurally adjusted ventilatory assist. The values of various ventilatory variables and other measurements were obtained 1 hour before neurally adjusted ventilatory assist and 1, 4, 12, and 24 hours after conversion to neurally adjusted ventilatory assist. During neurally adjusted ventilatory assist, the peak inspiratory pressure (20.12 ± 2.93 vs 14.15 ± 3.55 cm H2O; p < 0.05), mean airway pressure (11.15 ± 1.29 vs 9.57 ± 1.27 cm H2O; p < 0.05), and work of breathing (0.86 ± 0.22 vs 0.46 ± 0.12 J/L; p < 0.05) were significantly decreased, and the blood gas values were significantly improved. Significantly lower FIO2 and improved oxygen saturation were observed during neurally adjusted ventilatory assist compared with conventional ventilation support. The RSS values decreased and sustained during neurally adjusted ventilatory assist (4.85 ± 1.63 vs 3.21 ± 1.01; p < 0.001). The transition from synchronized intermittent mandatory ventilation to neurally adjusted ventilatory assist ventilation was associated with improvements in ventilator variables, oxygen saturation, and blood gas values in infants with bronchopulmonary dysplasia in a single center. This study suggests the possible clinical utility of neurally adjusted ventilatory assist as a weaning modality for bronchopulmonary dysplasia patients in the neonatal ICU.

Limited predictability of maximal muscular pressure using the difference between peak airway pressure and positive end-expiratory pressure during proportional assist ventilation (PAV).

BackgroundIf the proportional assist ventilation (PAV) level is known, muscular effort can be estimated from the difference between peak airway pressure and positive end-expiratory pressure (PEEP) (ΔP) during PAV. We conjectured that deducing muscle pressure from ΔP may be an interesting method to set PAV, and tested this hypothesis using the oesophageal pressure time product calculation.MethodsEleven mechanically ventilated patients with oesophageal pressure monitoring under PAV were enrolled. Patients were randomly assigned to seven assist levels (20–80%, PAV20 means 20% PAV gain) for 15 min. Maximal muscular pressure calculated from oesophageal pressure (Pmus, oes) and from ΔP (Pmus, aw) and inspiratory pressure time product derived from oesophageal pressure (PTPoes) and from ΔP (PTPaw) were determined from the last minute of each level. Pmus, oes and PTPoes with consideration of PEEPi were expressed as Pmus, oes, PEEPi and PTPoes, PEEPi, respectively. Pressure time product was expressed as per minute (PTPoes, PTPoes, PEEPi, PTPaw) and per breath (PTPoes, br, PTPoes, PEEPi, br, PTPaw, br).ResultsPAV significantly reduced the breathing effort of patients with increasing PAV gain (PTPoes 214.3 ± 80.0 at PAV20 vs. 83.7 ± 49.3 cmH2O•s/min at PAV80, PTPoes, PEEPi 277.3 ± 96.4 at PAV20 vs. 121.4 ± 71.6 cmH2O•s/min at PAV80, p < 0.0001). Pmus, aw overestimates Pmus, oes for low-gain PAV and underestimates Pmus, oes for moderate-gain to high-gain PAV. An optimal Pmus, aw could be achieved in 91% of cases with PAV60. When the PAV gain was adjusted to Pmus, aw of 5–10 cmH2O, there was a 93% probability of PTPoes <224 cmH2O•s/min and 88% probability of PTPoes, PEEPi < 255 cmH2O•s/min.ConclusionDeducing maximal muscular pressure from ΔP during PAV has limited accuracy. The extrapolated pressure time product from ΔP is usually less than the pressure time product calculated from oesophageal pressure tracing. However, when the PAV gain was adjusted to Pmus, aw of 5–10 cmH2O, there was a 90% probability of PTPoes and PTPoes, PEEPi within acceptable ranges. This information should be considered when applying ΔP to set PAV under various gains.

Treatment of neonates with respiratory distress syndrome by proportional assist ventilation plus synchronized intermittent mandatory ventilation: a comparison study.

The proportion assisted ventilation (PAV) can improve patient-ventilator interaction, reducing the incidence of end-expiratory asynchrony and increasing the time of synchrony. PAV could compensate for the leaks by elastic and resistive unloading and thus is ideal for neonates with uncuffed airways. The aim of this study was to compare the relevant clinical parameters of neonates with respiratory distress syndrome (RDS) who are supported by PAV plus synchronized intermittent mandatory ventilation (SIMV) and SIMV. Forty-six neonates diagnosed as RDS who required mechanical ventilation were randomly divided into observer group (support by PAV+SIMV mode, N.=23) and control group (support by SIMV mode, N.=23). The X-ray grading situation, the number of asynchrony-delayed trigger, mean arterial blood pressure (MABP), spontaneous respiratory rate (RR), heart rate (HR), blood gas analysis values and circulation and respiratory parameters at each timepoint after 30 minutes, 12, 24, 48 and 72 hours of mechanical ventilation were observed. The forty-four neonates in two groups have been cured, the other 2 neonates (one in each group) gave up treatment and automatically discharged. There were no statistically significant differences in male, gestational age, body weight, duration of mechanical ventilation, oxygen dependence and hospital stay between the two groups (all P>0.05). There were no statistically significant differences in MABP, HR and ratio of arterial-to-alveolar partial pressure of oxygen (a/APO<inf>2</inf>) at each time point after mechanical ventilation between the two groups(all P>0.05). The number of asynchrony-delayed trigger in observer group was lower than that in control group, the difference was statistically significant (P<0.05). The number of spontaneous RR in observer group was higher than that in control group. The difference was statistically significant (P<0.05). The PAV plus SIMV shows a good clinical effect in treatment of neonates with RDS. It could be better to use neonatal spontaneous breathing and might cause less damage to the lung than SIMV mode.

Comparing the Effect of Adaptive Support Ventilation (ASV) and Synchronized Intermittent Mandatory Ventilation (SIMV) on Respiratory Parameters in Neurosurgical ICU Patients.

BackgroundVarious modes of mechanical ventilation have different effects on respiratory variables. Lack of patients’ neuro-ventilatory coordination and increasing the work of breathing are major disadvantages in mechanically ventilated patients.ObjectivesThis study is conducted to compare the respiratory parameters differences in Adaptive support ventilation (ASV) and synchronized intermittent mandatory ventilation (SIMV) modes in neurosurgical ICU patients.MethodsIn a crossover study, patients under mechanical ventilation in neurosurgical ICU were enrolled. The patients alternatively experienced two types of ventilations for 30 minutes (adaptive support ventilation and synchronized intermittent mandatory ventilation). The respiratory parameters (tidal volume, respiratory rate, airway pressure, lung compliance, end-tidal carbon dioxide, peripheral oxygenation and respiratory dead space), hemodynamic variables, every 10 minutes and arterial blood gas analysis at the end of each 30 minutes were recorded. Results were compared and analyzed with SPSS v.19.ResultsSixty patients were involved in this study. In ASV mode, values including peak airway pressure (P-peak), end-tidal carbon dioxide (EtCO2), tidal volume and respiratory dead space were significantly lower than SIMV mode. Although the mean value for dynamic compliance had no significant difference in the two types of ventilation, it was better in ASV mode.ConclusionsASV mode compared with SIMV mode can lead to improve lung compliance and respiratory dead space.

Higher Work of Breathing at the End of Successful Spontaneous Breathing Trial Does Not Predict Extubation Failure

SESSION TITLE: Mechanical Ventilation & Respiratory Failure I SESSION TYPE: Original Investigation Poster PRESENTED ON: Wednesday, October 26, 2016 at 01:30 PM - 02:30 PM PURPOSE: Spontaneous breathing trial (SBT) is the gold standard process to assess readiness for extubation in mechanically ventilated patients. Approximately 15% of extubated patients require reintubation within 48 hours. We hypothesized that patients having higher work of breathing (WOB) at the end of successful SBT would have higher likelihood re-intubation. METHODS: We performed a prospective observational study to calculate the WOB at the end of first successful SBT using proportional assist ventilation (PAV) mode of ventilation in intubated medical intensive care unit patients. The ventilator used was Purtian Bennet 840 equipped with PAV+ software capable of showing WOB scale of 0.0 to 2.0 J/L in proportional assist ventilation (PAV) mode. WOB was further divided as: low WOB (0.0 to 0.3 J/L), normal WOB ( 0.3-0.7 J/L),high WOB (0.7-1.0 J/L) and very high WOB (1.2 to 2.0 J/L). At the end of successful SBT patient were switched over to PAV mode with 5 % of total WOB support provided by ventilator for 5 minutes and the data was collected. This data was not used for clinical management and patients were extubated based on judgement of the treating physician. Extubated patients were followed for 48 hours. Extubation failure was defined as the need for reintubation or the use of non-invasive positive pressure ventilation (NIPPV) for respiratory distress within 48 hours of extubation. RESULTS: Data from the first successful SBTs in 111 patients was analyzed. Only 67.5% (75/111) of patients were extubated on the same day of the first successful SBT. Overall rate of extubation failure was 11.7% (13/111, 8 patients needed re-intubation, 4 patients needed NIPPV and 1 patient needed NIPPV and was subsequently intubated). Three (23%) patients had high WOB and 0 (0%) patient had very high WOB in the failure group and 10 (16.4%) patients had high WOB and 3 (4.9%) patients had very high WOB in success group (p=0.86). CONCLUSIONS: Patient’s work of breathing at the end of successful SBT does not predict extubation failure. CLINICAL IMPLICATIONS: Higher WOB at the end of SBT is not associated with extubation failure. We need more research to figure out what measures we can add to SBT measurements to decrease the extubation failure. DISCLOSURE: The following authors have nothing to disclose: Prajan Subedi, Hala Karnib, Thomas Gilbert, Douglas Foreman, Mike Wagner, Daniel Keena No Product/Research Disclosure Information

The Comparison of Synchronized Intermittent Mandatory Ventilation with Nonsynchronised Intermittent Mandatory Ventilation in Newborn with Respiratory Failure and Transient Tachypnea

The Comparison of Synchronized Intermittent Mandatory Ventilation with Nonsynchronised Intermittent Mandatory Ventilation in Newborn with Respiratory Failure and Transient Tachypnea

機械換気による早産児の脳機能に対するフェンタニルの保護作用【JST・京大機械翻訳】

Objective To discuss the short-and long-term outcome of neuro-function with continuous Fentanyl infusion in ventilated prematurity. Methods Fifty-three ventilated preterm infants in the NICU of Nanjing Children's Hospital Affiliated to Nanjing Medical University from November 2012 to November 2014 were randomized into 2 groups of which 26 patients were in control group without receiving Fentanyl infusion, and 27 patients in study group.Study group received Fentanyl infusion at 1 μg /(kg·h) immediately after the intubation, and Fentanyl was reduced to half dose when ventilation settings were as below: mean airway pressure (MAP)<7 cmH2O(1 cmH2O=0.098 kPa), fraction of inspired oxygen (FiO2)<0.25, breathing rate<25 beats/min (synchronized intermittent mandatory ventilation), or MAP<10 cmH2O(high frequency oscillation). If patients were stable Fentanyl was weaned off in 30 minutes then the baby was extubated.Control group received 50 g/L glucose infusion at a same rate.Same stan-dard care was provided to all patients.(1) Ventilation settings including MAP, FiO2, arterial oxygen saturation, partial pressure of carbon dioxide in artery, partial pressure of oxygen in artery, respiratory rate, mean blood pressure, heart rate, duration of ventilation, side effects before and after intubation(2, 12, 24, 48 h) were compared. (2)Behavior responses to pain were assessed and compared by using premature infant pain profile (PIPP) and COMFORT scores.(3) Amplitude integrated electro-encephalogram (aEEG)in 37 weeks of corrected gestational age and neonatal behavioral neurological assessment (NBNA) scores in 40 weeks of corrected gestational age were compared. Results (1) There was no significant difference in ventilation settings, mean blood pressure, duration of ventilation, and side effects.Heart rates in control group were lower than those in study group in 12, 24 and 48 hours after intubation with significant difference(t=6.36, 7.01, 6.28, all P<0.05); respiratory rates in control group were lower than those in study group in 24 and 48 hours after intubation with significant difference(t=12.48, 10.34, all P<0.05). (2)Two hours after intubation PIPP and COMFORT scores in control group were lower than those in study group with significant difference (all P<0.05), especially in 12 hours after intubation(P<0.01). (3) NBNA and aEEG scores in control group were higher than those in study group (t=4.85, 3.27, all P<0.05). Conclusions Fentanyl infusion has potential protection for developing brain of ventilated prematurity by relieving pain during mechanic ventilation period, and improving NBNA scores and aEEG. Key words: Fentanyl infusion; Infant, preterm; Mechanical ventilation; Neuro-function

Impact of targeted-volume ventilation on pulmonary dynamics in preterm infants with respiratory distress syndrome.

Mechanical ventilation is an essential therapy in the treatment of respiratory failure in preterm infants. However, optimal ventilation strategy continues to be difficult to define. To compare the effects of volume guarantee (VG) combined with intermittent mandatory ventilation (SIMV) and VG combined with pressure support ventilation (PSV) on the pulmonary mechanics and short term prognosis in preterm infants with respiratory distress syndrome. Infants of <32 weeks gestational age ventilated for respiratory distress syndrome were randomized to receive either SIMV + VG or PSV + VG. The patient characteristics, ventilator variables including PIP, PEEP, MAP, VT, dynamic compliance, resistance, C20/C, and neonatal outcomes (IVH, ROP, oxygen dependency at 28th postnatal day and 36 weeks of PMA), mortality and extubation failure were recorded in each groups. Thirty-four infants were enrolled in to the study: 19 patients were randomized to the SIMV + VG group, and 15 patients to the PSV + VG group. No significant differences were observed between the two groups in terms of the birth weight, gestational age, gender, multiple pregnancy, delivery mode, and antenatal steroid treatment. The respiratory and ventilatory parameters were similar in the groups. The need for reintubation were common in SIMV + VG group (P < 0.01). Volume guaranteed ventilation combined with PSV may be a convenient method for preterm infants with RDS in terms of reducing postextubation atelectasis and the need for reintubation. Pediatr Pulmonol. 2017;52:213-216. © 2016 Wiley Periodicals, Inc.

Synchronized mechanical ventilation for respiratory support in newborn infants.

During synchronised mechanical ventilation, positive airway pressure and spontaneous inspiration coincide. If synchronous ventilation is provoked, adequate gas exchange should be achieved at lower peak airway pressures, potentially reducing baro/volutrauma, air leak and bronchopulmonary dysplasia. Synchronous ventilation can potentially be achieved by manipulation of rate and inspiratory time during conventional ventilation and employment of patient-triggered ventilation. To compare the efficacy of:(i) synchronised mechanical ventilation, delivered as high-frequency positive pressure ventilation (HFPPV) or patient-triggered ventilation (assist control ventilation (ACV) and synchronous intermittent mandatory ventilation (SIMV)), with conventional ventilation or high-frequency oscillation (HFO);(ii) different types of triggered ventilation (ACV, SIMV, pressure-regulated volume control ventilation (PRVCV), SIMV with pressure support (PS) and pressure support ventilation (PSV)). We used the standard search strategy of the Cochrane Neonatal Review group to search the Cochrane Central Register of Controlled Trials (CENTRAL 2016, Issue 5), MEDLINE via PubMed (1966 to June 5 2016), EMBASE (1980 to June 5 2016), and CINAHL (1982 to June 5 2016). We also searched clinical trials databases, conference proceedings, and the reference lists of retrieved articles for randomised controlled trials and quasi-randomised trials. Randomised or quasi-randomised clinical trials comparing synchronised ventilation delivered as HFPPV to CMV, or ACV/SIMV to CMV or HFO in neonates. Randomised trials comparing different triggered ventilation modes (ACV, SIMV, SIMV plus PS, PRVCV and PSV) in neonates. Data were collected regarding clinical outcomes including mortality, air leaks (pneumothorax or pulmonary interstitial emphysema (PIE)), severe intraventricular haemorrhage (grades 3 and 4), bronchopulmonary dysplasia (BPD) (oxygen dependency beyond 28 days), moderate/severe BPD (oxygen/respiratory support dependency beyond 36 weeks' postmenstrual age (PMA) and duration of weaning/ventilation.Eight comparisons were made: (i) HFPPV versus CMV; (ii) ACV/SIMV versus CMV; (iii) SIMV or SIMV + PS versus HFO; iv) ACV versus SIMV; (v) SIMV plus PS versus SIMV; vi) SIMV versus PRVCV; vii) SIMV vs PSV; viii) ACV versus PSV. Data analysis was conducted using relative risk for categorical outcomes, mean difference for outcomes measured on a continuous scale. Twenty-two studies are included in this review. The meta-analysis demonstrates that HFPPV compared to CMV was associated with a reduction in the risk of air leak (typical relative risk (RR) for pneumothorax was 0.69, 95% confidence interval (CI) 0.51 to 0.93). ACV/SIMV compared to CMV was associated with a shorter duration of ventilation (mean difference (MD) -38.3 hours, 95% CI -53.90 to -22.69). SIMV or SIMV + PS was associated with a greater risk of moderate/severe BPD compared to HFO (RR 1.33, 95% CI 1.07 to 1.65) and a longer duration of mechanical ventilation compared to HFO (MD 1.89 days, 95% CI 1.04 to 2.74).ACV compared to SIMV was associated with a trend to a shorter duration of weaning (MD -42.38 hours, 95% CI -94.35 to 9.60). Neither HFPPV nor triggered ventilation was associated with a significant reduction in the incidence of BPD. There was a non-significant trend towards a lower mortality rate using HFPPV versus CMV and a non-significant trend towards a higher mortality rate using triggered ventilation versus CMV. No disadvantage of HFPPV or triggered ventilation was noted regarding other outcomes. Compared to conventional ventilation, benefit is demonstrated for both HFPPV and triggered ventilation with regard to a reduction in air leak and a shorter duration of ventilation, respectively. In none of the trials was complex respiratory monitoring undertaken and thus it is not possible to conclude that the mechanism of producing those benefits is by provocation of synchronised ventilation. Triggered ventilation in the form of SIMV ± PS resulted in a greater risk of BPD and duration of ventilation compared to HFO. Optimisation of trigger and ventilator design with respect to respiratory diagnosis is encouraged before embarking on further trials. It is essential that newer forms of triggered ventilation are tested in randomised trials that are adequately powered to assess long-term outcomes before they are incorporated into routine clinical practice.

Intermittent Mandatory Ventilation: What's in a Name?

In Reply > That which we call a rose, By any other name would smell as sweet. > > —William Shakespeare Chatburn finds fault in our description of intermittent mandatory ventilation (IMV),[1][1] as we primarily discuss IMV as first described by Downs.[2][2] That is, a preset mandatory rate with

Abstract PR088

Background & Objectives: Proportional Assist Ventilation (PAV+) delivers positive pressure ventilation in proportion to instantaneous inspiratory effort, with some studies suggesting PAV+ may reduce ventilator dyssynchrony and the duration of weaning from the ventilator. This trial compared the time taken to wean critically ill patients from invasive mechanical ventilation using PAV+ as opposed to Pressure Support Ventilation (PSV). Secondary objectives were to compare the rate of tracheostomy, failed extubation, ICU and hospital length of stay (LOS), ICU and hospital mortality in patients studied. Materials & Methods: This study was conducted in a 15-bed Australian metropolitan ICU that admits approximately 1100 medical and surgical patients per year. Patients were included in the study if they had been ventilated on a controlled mode of ventilation and were deemed suitable for at least 48 hours of weaning on a spontaneous mode of ventilation. Patients were excluded if they were unlikely to survive for 24 hours, had a neuromuscular disease or injury, or a tracheostomy in-situ. Results: Fifty patients were randomised, with 25 randomised into each arm. There was no statistical difference in age (median = 65 vs 61 years; p = 0.76) and APACHE-III illness severity score (median = 76 vs 77.5, p = 0.75) between the PAV+ and PSV groups. There was no significant difference in the duration of weaning from mechanical ventilation (78.2 vs 130.5 hours; p = 0.53). There was a non-significant trends towards lower in-hospital mortality (12% vs 37.5%, p = 0.08). There was no significant difference in the ICU LOS (median = 9.3 vs. 11.8 days; p = 0.57) among patients in the PAV+ arm when compared to those in the PSV arm. Three patients in the PAV+ group did not respond to this ventilation mode and were changed to PSV. There was no significant difference in the proportion of patients requiring tracheostomy (20% vs 29.2%; p = 0.68) or reintubation (4% vs 8.3%; p = 0.97). Conclusion: The duration of weaning from mechanical ventilation was comparable with PAV+ and PSV ventilation. A trend towards reduced hospital mortality was noted with PAV+ weaning. A larger study may provide further information on the advantages and disadvantages of PAV+ compared to other modes of spontaneous ventilation.

Synchronized mechanical ventilation for respiratory support in newborn infants.

During synchronised mechanical ventilation, positive airway pressure and spontaneous inspiration coincide. If synchronous ventilation is provoked, adequate gas exchange should be achieved at lower peak airway pressures, potentially reducing baro/volutrauma, air leak and bronchopulmonary dysplasia. Synchronous ventilation can potentially be achieved by manipulation of rate and inspiratory time during conventional ventilation and employment of patient-triggered ventilation. To compare the efficacy of:(i) synchronised mechanical ventilation, delivered as high-frequency positive pressure ventilation (HFPPV) or patient-triggered ventilation (assist control ventilation (ACV) and synchronous intermittent mandatory ventilation (SIMV)), with conventional ventilation or high-frequency oscillation (HFO);(ii) different types of triggered ventilation (ACV, SIMV, pressure-regulated volume control ventilation (PRVCV), SIMV with pressure support (PS) and pressure support ventilation (PSV)). We used the standard search strategy of the Cochrane Neonatal Review group to search the Cochrane Central Register of Controlled Trials (CENTRAL 2016, Issue 5), MEDLINE via PubMed (1966 to June 5 2016), EMBASE (1980 to June 5 2016), and CINAHL (1982 to June 5 2016). We also searched clinical trials databases, conference proceedings, and the reference lists of retrieved articles for randomised controlled trials and quasi-randomised trials. Randomised or quasi-randomised clinical trials comparing synchronised ventilation delivered as HFPPV to CMV, or ACV/SIMV to CMV or HFO in neonates. Randomised trials comparing different triggered ventilation modes (ACV, SIMV, SIMV plus PS, PRVCV and PSV) in neonates. Data were collected regarding clinical outcomes including mortality, air leaks (pneumothorax or pulmonary interstitial emphysema (PIE)), severe intraventricular haemorrhage (grades 3 and 4), bronchopulmonary dysplasia (BPD) (oxygen dependency beyond 28 days), moderate/severe BPD (oxygen/respiratory support dependency beyond 36 weeks' postmenstrual age (PMA) and duration of weaning/ventilation.Eight comparisons were made: (i) HFPPV versus CMV; (ii) ACV/SIMV versus CMV; (iii) SIMV or SIMV + PS versus HFO; iv) ACV versus SIMV; (v) SIMV plus PS versus SIMV; vi) SIMV versus PRVCV; vii) SIMV vs PSV; viii) ACV versus PSV. Data analysis was conducted using relative risk for categorical outcomes, mean difference for outcomes measured on a continuous scale. Twenty-two studies are included in this review. The meta-analysis demonstrates that HFPPV compared to CMV was associated with a reduction in the risk of air leak (typical relative risk (RR) for pneumothorax was 0.69, 95% confidence interval (CI) 0.51 to 0.93). ACV/SIMV compared to CMV was associated with a shorter duration of ventilation (mean difference (MD) -38.3 hours, 95% CI -53.90 to -22.69). SIMV or SIMV + PS was associated with a greater risk of moderate/severe BPD compared to HFO (RR 1.33, 95% CI 1.07 to 1.65) and a longer duration of mechanical ventilation compared to HFO (MD 1.89 days, 95% CI 1.04 to 2.74).ACV compared to SIMV was associated with a trend to a shorter duration of weaning (MD -42.38 hours, 95% CI -94.35 to 9.60). Neither HFPPV nor triggered ventilation was associated with a significant reduction in the incidence of BPD. There was a non-significant trend towards a lower mortality rate using HFPPV versus CMV and a non-significant trend towards a higher mortality rate using triggered ventilation versus CMV. No disadvantage of HFPPV or triggered ventilation was noted regarding other outcomes. Compared to conventional ventilation, benefit is demonstrated for both HFPPV and triggered ventilation with regard to a reduction in air leak and a shorter duration of ventilation, respectively. In none of the trials was complex respiratory monitoring undertaken and thus it is not possible to conclude that the mechanism of producing those benefits is by provocation of synchronised ventilation. Triggered ventilation in the form of SIMV ± PS resulted in a greater risk of BPD and duration of ventilation compared to HFO. Optimisation of trigger and ventilator design with respect to respiratory diagnosis is encouraged before embarking on further trials. It is essential that newer forms of triggered ventilation are tested in randomised trials that are adequately powered to assess long-term outcomes before they are incorporated into routine clinical practice.

Criterion validity and sensitivity to change of the Early Rehabilitation Index (ERI): results from a German multi-center study.

BackgroundEvaluation of functional status is difficult in neurological and neurosurgical early rehabilitation patients. The Early Rehabilitation Index (ERI) was introduced in Germany over 20 years ago, but since then validation studies are lacking. The ERI (range −325 to 0 points) includes highly relevant items including the necessity of intermittent mechanical ventilation or tracheostomy.MethodsThe present paper analyzed data from a German multi-center study, enrolling 754 neurological early rehabilitation patients. Together with ERI, Barthel Index (BI), Glasgow Coma Scale (GCS), Glasgow Outcome Score Extended, Coma Remission Scale (CRS), Functional Ambulation Categories and length of stay were obtained.ResultsERI showed significant improvements from admission to discharge (p < 0.001). In addition, there were significant correlations of the ERI upon admission and at discharge with BI, CRS and GCS.ConclusionsEvaluation of our study data suggest that the ERI may be used as a valid assessment instrument for neurological and neurosurgical early rehabilitation patients.