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. 2009 Winter;20(4):e115-23.
doi: 10.1155/2009/808209.

Potential intensive care unit ventilator demand/capacity mismatch due to novel swine-origin H1N1 in Canada

Paul Smetanin  1 , David Stiff, Anand Kumar, Paul Kobak, Ryan Zarychanski, Neil Simonsen, Frank Plummer
Affiliations

Potential intensive care unit ventilator demand/capacity mismatch due to novel swine-origin H1N1 in Canada

Paul Smetanin et al. Can J Infect Dis Med Microbiol. 2009 Winter.

Abstract
in English, French

Purpose: To investigate the ability of Canadian intensive care units (ICUs) and ventilators to handle widespread re-emergence of the swine-origin H1N1 virus in the context of an aggressive strategy of vaccination.

Method: Data collected during the first wave in Winnipeg, Manitoba, were applied to a variety of second wave pandemic models to determine potential ICU and ventilator demand.

Results: For attack rates greater than 20% to 25%, significant shortages in ventilators may be expected across Canada regardless of the duration of the pandemic if vaccination is not considered. The shortfall arises largely due to the extended durations that patients must remain on ventilation. From the Winnipeg study, 50% of patients required ventilation for more than two weeks. For larger attack rates of 35%, ventilator demand may exceed capacity for over five weeks, with a peak shortfall of 700 ventilators. Vaccination can significantly reduce the attack rates, and is expected to reduce ventilator demand to manageable levels

Conclusion: Canada's health care system must be prepared for the possibility of a significant influx of ICU patients during the second wave of swine-origin H1N1. Efficient vaccination and other disease prevention measures can reduce the attack rate to manageable levels.

OBJECTIF :: Vérifier si les unités de soins intensifs (USI) canadiennes et les respirateurs dont elles disposent permettront d’assurer la prise en charge d’une importante ré-émergence de la grippe AH1N1 dans le contexte d’une stratégie énergique de vaccination.

MÉTHODE :: Les données recueillies durant la première vague de la pandémie de grippe AH1N1 à Winnipeg, au Manitoba, ont été appliquées à une variété de modèles pandémiques applicables à une seconde vague afin d’évaluer les pressions potentielles exercées sur les USI et la demande de respirateurs.

RÉSULTATS :: Si les taux d’attaque dépassent 20 % à 25 %, d’importantes pénuries de ventilateurs sont à prévoir partout au Canada, peu importe la durée de la pandémie et si on ne tient pas compte de la vaccination. La pénurie serait principalement due à la durée de l’intubation des patients. Selon l’étude de Winnipeg, 50 % des patients sont restés sous respirateur pendant plus de deux semaines. Si les taux d’attaque dépassent 35 %, les demandes de ventilateurs pourraient excéder la capacité pendant plus de cinq semaines, avec une pénurie de 700 ventilateurs au pire de la crise. La vaccination peut significativement réduire les taux d’attaque et on s’attend à ce qu’elle maintienne la demande de ventilateurs à des niveaux gérables.

CONCLUSION :: Le système de soins de santé canadien doit se préparer à un afflux massif de patients dans les USI au cours de la seconde vague de grippe AH1N1. Une vaccination efficace et d’autres mesures de prévention de la maladie peuvent contribuer à maintenir le taux d’attaque à des niveaux gérables

Keywords: H1N1; Influenza; Intensive care; Mathematical modelling Pandemic.

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Figures

Figure 1)
Figure 1)
Patient flow diagram from symptomatic through to recovery or death. ICU Intensive care unit
Figure 2)
Figure 2)
The cumulative distribution of times spent in each hospitalization state used in the model. Prehospitalization is the time between symptom onset and hospitalization. Pre-intensive care unit (Pre-ICU) is the time between hospitalization and admission to the ICU. ICU Only refers to patients who are in ICU but do not require ventilation and recover. Pre-Ventilation is the time patients spend in ICU before requiring ventilation. Ventilation/Recovery is the duration on ventilation for patients who recover, while Ventilation/Death is the time on ventilation for those who die. Finally, Post-Ventilation is the time that patients spend in ICU after ventilation before being released from ICU
Figure 3)
Figure 3)
Typical cumulative admissions and releases from the intensive care unit (ICU) for a population of one million, attack rate 25% and duration of eight weeks. The number of patients in ICU is the difference between the cumulative admissions and releases
Figure 4)
Figure 4)
Number of patients on ventilation as a function of time for a pandemic across Canada with 35% attack rate and a duration of 10 weeks. The horizontal line corresponds to the number of ventilators available in Canada for H1N1 patients under the assumption that two-thirds of the total ventilators could be made available
See this image and copyright information in PMC

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