A randomized single-center controlled trial of synchronized intermittent mandatory ventilation with heliox in newborn infants with meconium aspiration syndrome

OBJECTIVE

This study aimed to investigate the beneficial effects of synchronized intermittent mandatory ventilation (SIMV) with heliox in newborn infants with meconium aspiration syndrome (MAS).

METHODS

Seventy-one newborn infants with MAS in the neonatal intensive care unit (NICU) of Daping Hospital of Army Medical University were enrolled in the trial. Infants treated with SIMV were randomized and divided into the heliox group (n = 35) and control group (n = 36). The heliox group received heliox for 6 h followed by air-oxygen mixed gas, and the control group received air-oxygen mixed gas. The primary outcome measures were PaO₂ /FiO₂ (P/F) and the extubation time. The secondary outcome measures were the incidence of mechanical ventilation complications, hospital length of stay in the NICU, blood gas analysis, and inflammation markers.

RESULTS

The P/F in the heliox group was significantly better than that in the control group (p < .001). The extubation time and hospital length of stay in the NICU in the heliox group were shorter than those in the control group (p < .001). The inflammation markers at 6 h and myocardial injury markers at 24 h were decreased compared with those at 0 h, and those in the heliox group were more significantly decreased than those in the control group ([interleukin {IL}-6/IL-8/tumor necrosis factor α] p < .001, [C-reaction protein] p = .012; [creatine kinase] p < .001, [CK-MB] p = .041).

CONCLUSION

Heliox appears to be more effective in reducing the length of ventilation and increasing carbon dioxide eliminations than an air-oxygen mixture in infants with MAS under the support of SIMV.

A comparison of the effect of bi-level positive airway pressure and synchronized intermittent mandatory ventilation in preterm infants with respiratory distress syndrome

OBJECTIVE

Bi-level positive airway pressure (BiPAP) and synchronized intermittent mandatory ventilation (SIMV) can be used to achieve peak inspiratory pressure and positive end-expiratory pressure to avoid alveolar collapse and improve oxygenation in preterm infants during the treatment of respiratory distress syndrome (RDS), and there is an urgent demand for evaluating the effects and prognoses of these two ventilation modes.

STUDY DESIGN

We conducted a retrospective study on preterm infants (≤32 weeks and <2500 g) from March 2015 to March 2020 with BiPAP (n = 63) and SIMV (n = 63). The primary outcomes were successful treatment and weaning within 72 h, the demand for a second pulmonary surfactant supply and the need for a second respiratory support. The secondary outcome was the incidence of complications.

RESULTS

There were no significant differences (p > .05) in the primary outcomes or the incidence of complications (pneumonia, apnea, respiratory failure, air leak syndrome, persistence of patent ductus arteriosus, neonatal sepsis, necrotizing enterocolitis, retinopathy of prematurity, and intraventricular hemorrhage). There were significant differences (p < .05) in the incidence of pulmonary hemorrhage, bronchopulmonary dysplasia and IVH (≥grade II).

CONCLUSIONS

Although both BiPAP and SIMV achieved good early treatment outcomes of RDS in preterm infants, BiPAP support is recommended for reducing the incidence of pulmonary hemorrhage, bronchopulmonary dysplasia and IVH (≥grade II) if infants are tolerant. Attempts should be made to prevent these complications from happening with the use of SIMV support if infants are intolerant.

[A comparative study of two ventilation modes in the weaning phase of preterm infants with respiratory distress syndrome]

OBJECTIVE

To compare the efficacy between synchronized intermittent mandatory ventilation (SIMV) and pressure support ventilation with volume guarantee (PSV+VG) in the weaning phase of preterm infants with respiratory distress syndrome (RDS).

METHODS

Forty preterm infants with RDS who were admitted to the neonatal intensive care unit between March 2016 and May 2017 were enrolled as subjects. All infants were born at less than 32 weeks' gestation and received mechanical ventilation. These patients were randomly and equally divided into SIMV group and PSV+VG group in the weaning phase. Ventilator parameters, arterial blood gas, weaning duration (from onset of weaning to extubation), duration of nasal continuous positive airway pressure (NCPAP) after extubation, extubation failure rate, the incidence rates of pneumothorax, patent ductus arteriosus (PDA) and bronchopulmonary dysplasia (BPD), and the mortality rate were compared between the two groups.

RESULTS

The PSV+VG group had significantly decreased mean airway pressure, weaning duration, duration of NCPAP after extubation, and extubation failure rate compared with the SIMV group (P<0.05). There were no significant differences in arterial blood gas, mortality, or incidence rates of pneumothorax, PDA and BPD between the two groups (P>0.05).

CONCLUSIONS

For preterm infants with RDS, the PSV+VG mode may be a relatively safe and effective mode in the weaning phase. However, multi-center clinical trials with large sample sizes are needed to confirm the conclusion.

Effect of ventilator mode on patient-ventilator synchrony and work of breathing in neonatal pigs

BACKGROUND

Patient-ventilator asynchrony can result in increased work of breathing (WOB) and need for increased sedation, as well as respiratory muscle fatigue and prolonged mechanical ventilation. Different ventilator modes may result in varying degrees of asynchrony and WOB.

OBJECTIVE

The objectives of this study were to assess the incidence of asynchrony and the effect of asynchrony on WOB in three modes of ventilation: pressure regulated volume control (PRVC), synchronized intermittent mandatory ventilation/volume control plus pressure support (SIMV/VC plus PS), and SIMV/PRVC plus PS.

METHODS

Ten piglets (2.1 ± 0.3 kg) were studied, each in the healthy and surfactant-depleted, lung-injured state. Piglets were sedated, intubated, and ventilated with the three modes of ventilation randomly applied. Piglets then underwent surfactant washout, after which the lungs were re-recruited, and the modes of ventilation were repeated. Airway flow and pressure waveforms were acquired via pneumotachograph. Waveforms were analyzed for patient-ventilator asynchrony and pressure time product (PTP) as an estimate of patient WOB. RESULTS SIMV/VC plus PS had the highest incidence of asynchrony. The incidence of asynchrony was less in the injured lung. PTP (cm H₂ O*S) was increased for SIMV/VC plus PS (healthy 0.10 ± 0.12; injured 0.15 ± 0.13) compared to PRVC (healthy 0.05 ± 0.05; injured 0.06 ± 0.03), (P < 0.03) in both the healthy and injured lung models.

CONCLUSIONS

Asynchrony and WOB are highest with SIMV/VC plus PS. If SIMV is utilized, SIMV/PRVC plus a PS that optimizes tidal volume may be preferable. PRVC has the least asynchrony and WOB in the injured lung.

Should Intermittent Mandatory Ventilation Be Abolished?

Intermittent mandatory ventilation (IMV) was introduced nearly 50 years ago. Despite the initial fanfare and early adoption by many, the role of IMV continues to be questioned. The use of small tidal volumes complicates the application of IMV, and issues with work of breathing, weaning and lack of clear advantages have many calling for a moratorium on its use. Spontaneous breathing, however, has a number of salutatory effects on gas exchange, the distribution of ventilation, and hemodynamics. These issues will be explored in light of a growing body of evidence.

A comparison of synchronized intermittent mandatory ventilation and pressure-regulated volume control ventilation in elderly patients with acute exacerbations of COPD and respiratory failure

BACKGROUND

COPD is the third leading cause of death worldwide. Acute exacerbations of COPD may cause respiratory failure, requiring intensive care unit admission and mechanical ventilation. Intensive care unit patients with acute exacerbations of COPD requiring mechanical ventilation have higher mortality rates than other hospitalized patients. Although mechanical ventilation is the most effective intervention for these conditions, invasive ventilation techniques have yielded variable effects.

OBJECTIVE

We evaluated pressure-regulated volume control (PRVC) ventilation treatment efficacy and preventive effects on pulmonary barotrauma in elderly COPD patients with respiratory failure.

PATIENTS AND METHODS

Thirty-nine intubated patients were divided into experimental and control groups and treated with the PRVC and synchronized intermittent mandatory ventilation - volume control methods, respectively. Vital signs, respiratory mechanics, and arterial blood gas analyses were monitored for 2-4 hours and 48 hours.

RESULTS

Both groups showed rapidly improved pH, partial pressure of oxygen (PaO2), and PaO2 per fraction of inspired O2 levels and lower partial pressure of carbon dioxide (PaCO2) levels. The pH and PaCO2 levels at 2-4 hours were lower and higher, respectively, in the test group than those in the control group (P<0.05 for both); after 48 hours, blood gas analyses showed no statistical difference in any marker (P>0.05). Vital signs during 2-4 hours and 48 hours of treatment showed no statistical difference in either group (P>0.05). The level of peak inspiratory pressure in the experimental group after mechanical ventilation for 2-4 hours and 48 hours was significantly lower than that in the control group (P<0.05), while other variables were not significantly different between groups (P>0.05).

CONCLUSION

Among elderly COPD patients with respiratory failure, application of PRVC resulted in rapid improvement in arterial blood gas analyses while maintaining a low peak inspiratory pressure. PRVC can reduce pulmonary barotrauma risk, making it a safer protective ventilation mode than synchronized intermittent mandatory ventilation - volume control.

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.