Augmentation of Mechanical Ventilation in Hospitals
A Guide for the Evaluation and Stockpiling of Positive Pressure Ventilation Equipment
By Richard E. Waldhorn, M.D., May 18, 2006
How Will Hospitals Accommodate a Surge of Critical Care Patients?
How should hospitals increase their capacity to provide mechanical ventilation for a surge of patients with acute respiratory failure during a mass casualty event or influenza pandemic? Rubinson and colleagues address this issue in a recently published article [Rubinson L, et al. Positive Pressure Ventilation Equipment for Mass Casualty Respiratory Failure. Biosecurity and Bioterror 2006;4(2):1-11]. Their report is based on an evaluation and assessment of a wide range of positive pressure ventilation (PPV) equipment, with the goal of determining the suitability of each device for mass casualty care. The article provides information useful for determining which types PPV equipment would be the best choice for hospitals in need of a serviceable alternative to full feature ventilators, which will be in short supply and are too expensive for hospitals to stockpile.
Existing Reserves of Ventilators are Not Adequate
In a severe pandemic, the need for mechanical ventilators may far exceed hospital and Strategic National Stockpile (SNS) reserves. Using the CDC’s FluSurge modeling software to predict the effects of HHS planning assumptions for a severe pandemic, it can be predicted that in a typical city, with a pandemic of moderate duration and attack rate (8 weeks and 25% respectively), at epidemic peak (week 5), flu patients would require 191% of all non-intensive care unit (ICU) beds, 461% of all available ICU beds, and 198% of all available mechanical ventilators (see CBN Report: Prediciting the Impact of a Flu Epidemic, 12-01-05). Even with greatly increased reserves, the SNS will not be able to provide supplies of ventilators adequate to meet the needs of hospitals in a pandemic. Moreover, they will not be able to rent equipment, and it is not practical for hospitals to purchase, maintain, and store expensive full feature mechanical ventilators just to have them on hand in case they are needed.
Alternative PPV Equipment Can be Used to Augment Reserves
The authors assert that alternative positive pressure ventilation (PPV) equipment, designed and used for short term PPV in non-ICU locations, but suitable for definitive mechanical ventilation during mass casualty events, should be considered. This equipment is available, less expensive, and more easily stockpiled than full feature mechanical ventilators. Alternative PPV equipment must be easy for non-critical-care staff, with limited training and experience, to operate, as it is likely that they will be called upon to help manage patients with respiratory failure in a mass casualty setting. Because it may also have to be used outside of an ICU, alternative PPV equipment must have appropriate alarm capabilities, battery power, and the ability to function with either high and low pressure oxygen sources.
The authors conclude that portable ventilators with internal compressors and oxygen blenders will be the most oxygen sparing and will meet most of the criteria for the ideal mass casualty PPV device. They also point out that a stockpile of PPV equipment alone will not be adequate or sufficient. Shortages of critical care staff will be a limiting factor in any emergency response, which means that cross training of non-critical-care staff must be central to any effort to expand hospital surge capacity.