Mechanical ventilatory support

Two 19-year-old-girls developed pulmonary edema after taking massive overdoses of verapamil (6000 mg and 7200 mg). In each case a chest X-ray showed diffuse bilateral patchy infiltration. Left ventricular size and function was normal on transthoracic echocardiography. They were both treated successfully with mechanical ventilatory support. 

In a small number of patients whose respiratory center is depressed by long-term retention of carbon dioxide, injury, or drugs, ventilation is maintained largely by stimulation of carotid and aortic chemoreceptors, commonly referred to as the hypoxic drive. The provision of too much oxygen can depress this drive, resulting in respiratory acidosis. In these cases, supplemental oxygen should be titrated carefully to ensure adequate arterial saturation. If hypoventilation results, then mechanical ventilatory support with or without tracheal intubation should be provided. 

Principles of Positive Pressure Mechanical Ventilatory Support... 

Chatila W, Kreimer DT, Criner GJ. Quality of life in survivors of prolonged mechanical ventilatory support. Crit Care Med 2001 29(4) 737-742. 

Only a small percentage of patients require ventilation for at least six hours per day for 21 days (2 These patients are often older, have more comorbid illnesses, and, liequendy, have underlying obstmetive lung disease (3,4). Patients who have had a shorter duration of mechanical ventilatory support during surgery are more likely to be successfully weaned (5,6). 

Duiverman ML, Bladder G, Meinesz AF, et al. Home mechanical ventilatory support in patients with restrictive ventilatory disorders a 48-year experience. Respir Med 2006 100 56-65. 

Bach JR, Campagnolo DL Hoeman S. Life satisfaction of individuals with Duchenne muscular dystrophy using long-term mechanical ventilatory support Am J Phys Med Rehabil 1991 70(3) 129-35. 

In summary, whereas for obvious reasons the immediate focus in patients with ventilatory failure is the prompt initiation of effective mechanical ventilatory support, it is also necessary for the health care professional to be mindful of the management of other aspects of their care, such as bronchodilators, steroids, antibiotics, and oxygen as well as issues such as secretion clearance, positioning, mobilization, and the potential for aspiration, especially among those patients ventilated through a tracheostomy. Many of these points are amplified elsewhere in this text. 

Oxygen alone, although preventing the nocturnal desaturation, often results in unacceptably high levels of Pcx>2. Diuretics and tracheostomy alone, although providing a temporary improvement, will at best delay the need for mechanical ventilatory support. 

Chian LL. Description of anxiety levels by individual differences and clinical factors in patients receiving mechanical ventilatory support Heart Lung 2003 32(4) 275-282. 

The duration of mechanically assisted ventilation appears to be very important for determining the risk of nosocomial pneumonia. In children, nosocomial pneumonia is rare during the first 72 hours of intubation (3). The risk increases sharply after 72 hours (3). Studies in adults suggest that, after 10 days of mechanical ventilatory support, the rate of infection declines sharply (39). After 10 days, it is likely that some of the other risk factors contributing to the development of nosocomial pneumonia in critically ill children (e.g., sepsis, shock, surgery, anesthesia) will have resolved. 

Ixhemia reperfusion injury leads to severe graft dysfunction, known as the reimplantation response, in 10-20% of lung transplant recipients (28). This noncatdiogenic pulmonary edema marrrfests as severe hypoxia and pulmonary infiltrates and may require prolonged mechanical ventilatory support. Treatment consists of ventilatory support, positive end-expiratory pressure, diuresis, and inhaled nitric oxide and may require extracorporeal membrane oxygenation (33,34). 

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