Pressure-controlled ventilation via a mini-tracheostomy tube for patients with neuromuscular disease

Heart rate variability and hypercapnia in Duchenne muscular dystrophy

OBJECTIVE

To investigate the relationship between heart rate variability and hypercapnia.

PATIENTS AND METHODS

We measured the coefficient of variation of R-R interval (CVrr) and arterial blood gas pressures in 73 patients with Duchenne muscular dystrophy.

RESULTS

CVrr was negatively correlated with arterial partial pressure of carbon dioxide (PaCO(2)). In patients whose CVrr was larger than 5%, 84% of them had no hypercapnia while the other 16% had hypercapnia (PaCO(2) >45 mmHg). In contrast, 27% of those with CVrr smaller than 3% had no hypercapnia, 73% had hypercapnia and 47% had severe hypercapnia (PaCO(2) >50 mmHg).

CONCLUSION

We first showed that CVrr was negatively correlated with PaCO(2), and propose that abnormally low CVrr indicates respiratory insufficiency in patients with Duchenne muscular dystrophy.

Transtracheal Open Ventilation in Acute Respiratory Failure Secondary to Severe Chronic Obstructive Pulmonary Disease Exacerbation

RATIONALE

Patients who fail noninvasive ventilation are generally intubated and are then subjected to complications of invasive mechanical ventilation. With transtracheal open ventilation, ventilator support is delivered through an uncuffed small bore minitracheostomy tube, which eliminates pooling of secretions above the cuff and thus reduces the risk of tracheobronchial microbial colonization.

OBJECTIVE

To compare transtracheal open ventilation (treatment group) with conventional invasive ventilation (control group) in patients with exacerbation of chronic obstructive pulmonary disease who initially failed noninvasive ventilation.

METHODS

Patients were randomized to receive trans-tracheal open ventilation (n=19) or conventional invasive ventilation (n=20).

MEASUREMENTS AND MAIN RESULTS

There was no difference in arterial blood gases after 1 and 30 h between the two groups. Two patients receiving transtracheal open ventilation and 13 undergoing conventional ventilation had complications (p<0.0001). Compared with conventional ventilation, transtracheal open ventilation significantly decreased both the duration of mechanical ventilation (7.6+/-4.7 vs. 18.6+/-10.6 d, p<0.0001) and length of stay in the intensive care unit (10.2+/-4.5 vs. 21.3+/-9.7 d, p<0.0001).

CONCLUSIONS

Transtracheal open ventilation was as effective as conventional ventilation in maintaining adequate gas exchange and reducing complications, duration of mechanical ventilation, and intensive care unit length of stay.

Update on respiratory management of critically ill neurologic patients

Respiratory failure complicates a number of acute neurologic conditions, most notably neuromuscular diseases (eg, Guillain-Barré syndrome and myasthenia gravis) and stroke. In addition, pulmonary complications, particularly pneumonia and atelectasis, are fairly common in patients with these diagnoses; their prevention and early recognition are crucial to avoid detrimental consequences. This review discusses recent studies related to predictors of respiratory failure and pneumonia, strategies of respiratory care and ventilatory support, functional prognosis, and withdrawal of mechanical ventilation in patients with acute neuromuscular respiratory failure and stroke.

Physiologic comparison between conventional mechanical ventilation and transtracheal open ventilation in acute traumatic quadriplegic patients*

OBJECTIVE

To evaluate the efficacy of mechanical ventilation administered through a small-bore, uncuffed tracheotomy tube, so-called transtracheal open ventilation (TOV), in comparison with conventional mechanical ventilation via a cuffed tracheal tube (endotracheal invasive ventilation, EIV).

DESIGN

Physiologic study.

SETTING

Intensive care unit of a referral trauma center.

PATIENTS

Ten acute quadriplegic patients.

INTERVENTIONS

In acute quadriplegic patients receiving EIV, TOV was subsequently applied via an uncuffed, small-bore tube (internal diameter of 4 or 5 mm).

MEASUREMENTS AND MAIN RESULTS

Compared with EIV, arterial blood gases were not significantly different after 1 hr of TOV (Pao2/Fio2, 222.8 +/- 60.9 vs. 218.5 +/- 60.3; Paco2, 37.8 +/- 7.1 torr [5.04 +/- 0.95 kPa] vs. 35.5 +/- 6.8 torr [4.73 +/- 0.91 kPa], for EIV and TOV, respectively). Respiratory rate (19.5 +/- 4.7 vs. 19.6 +/- 5 breaths/min) and inspiratory effort (pressure-time product of esophageal pressure during a 1-min period, 125.9 +/- 48.4 vs. 112.8 +/- 36.4 cm H2O.sec.min) were also no different between the two modes. After 24 hrs of TOV, compared with EIV and TOV after 1 hr, respiratory rate and arterial blood gases remained stable, and the pressure-time product of esophageal pressure during a 1-min period was slightly, but significantly, reduced (83.5 +/- 16.6 cm H2O.sec.min, p < .05).

CONCLUSIONS

In acute quadriplegic patients receiving mechanical ventilation, TOV was as effective as EIV in providing ventilatory support.

Tracheostomy tube enabling speech during mechanical ventilation

BACKGROUND

A voice tracheostomy tube (VTT) was developed to enable patients to speak during mechanical ventilation.

METHODS

The VTT has slits cut in it and is covered on part of its side with an elastic cuff, enabling the cuff to expand with positive pressure from the ventilator on inspiration and to deflate on expiration. By this mechanism, inspired air from the ventilator goes to the lung with the cuff inflated, and some of the expired air passes out around the deflated cuff and discharges through the glottis, allowing sufficient ventilation and also enabling vocal fold vibration. An experiment using a model lung showed that there was little leakage on inspiration even for low lung compliance and high airway pressure, and that the leakage volume on expiration was approximately 40% of the ventilated volume, ie, the volume discharging through the vocal fold in clinical use.

RESULTS

Sixteen patients who had been managed by ventilation via a conventional tracheostomy tube were switched to the VTT. All patients except one were able to speak after switching to the VTT without change in PaO(2) and PaCO(2). There were no complications associated with the use of the VTT. Bronchoscopy showed that the cuff of the VTT did not damage the tracheal mucosa.

CONCLUSION

The VTT enables patients to speak during mechanical ventilation with sufficient ventilation and without aspiration and damage to the tracheal mucosa, even in patients with low lung compliance.

Translaryngeal open ventilation to treat acute respiratory failure in acute exacerbation of chronic obstructive pulmonary disease. A preliminary report

PURPOSE

To describe a minimally invasive alternative to conventional mechanical ventilation, using a small size uncuffed nasotracheal tube (translaryngeal open ventilation) paired with pressure control ventilation, in acute respiratory failure complicating chronic obstructive pulmonary disease (COPD).

CLINICAL FEATURES

Two cooperative COPD patients, who failed noninvasive mechanical ventilation, were intubated nasotracheally. Mechanical ventilation was initiated in pressure control mode via an uncuffed 6 mm tube.

RESULTS

Respiratory rate improved after 1 hour (from 44 to 28 breaths*min(-1) in case 1 and from 32 to 25 breaths*min(-1) in case 2); PaC0(2) decreased (from 120 to 62 mmHg in case 1 and from 69 to 51 mmHg in case 2); with pressure control mode levels of 45 cm H(2)O and 55 cm H(2)O respectively. PaO(2) increased from 40 mmHg (with FIO(2) 0.3) to 55 mmHg (with FIO(2) 0.3) in the first patient and from 55 mmHg (with FIO(2) 0.4) to 60 mmHg (with FIO(2) 0.4 ) in the second patient; pH improved from 7.18 to 7.31 in case 1 and from 7.22 to 7.39 in case 2. Patients were able to trigger the ventilator, speak, swallow and to clear secretions spontaneously. Both patients were ventilated for three days in this manner without any adverse effects. Both survived and were discharged home after 20 and 18 days in hospital respectively.

CONCLUSION

This very preliminary report suggests that, in carefully selected patients who fail mask ventilation, mechanical support with translaryngeal open ventilation can improve gas exchange, breathing pattern and tachypnea, without hindering glottic function.