Table 4.
Summary of studies describing intensive care unit (ICU) or critically ill patients with pandemic influenza A (H1N1pdm09)*
| Study name (Size) | Location and time period | Case definition | Ages | Most common chronic conditions (%)** | Obesity (%)*** | Mechanical ventilation (%) | ARDS (%) | Death (%) | Antiviral agent receipt (%) |
|---|---|---|---|---|---|---|---|---|---|
| Pediatric and adult studies | |||||||||
| This study (n = 154) | United States May–June 2009; September–October 2009 | ICU admission† | Median (IQR): 30 years (14–47) | Asthma: 24 Neurologic disease: 17 | 51 | 58 | 38 | 24 | 83 |
| Dominguez‐Cherit 12 (n = 58) | Mexico March–June 2009 | Critical illness††,††† | Median (range): 44 years (10–83) | Hypertension: 26 Diabetes: 17 | 36 | 93 | – | 41 | 78 |
| Kumar 13 (n = 168) | Canada April–August 2009 | Critical illness††,‡ | Mean (SD) : 32 years (21) | Chronic lung disease: 41 Hypertension: 24 | 33 | 81 | – | 17 | 91 |
| Miller 14 (n = 47) | United States (Salt Lake County, Utah) May–June 2009 | ICU admission† | Median (range): 34 years (15–62) | Asthma: 30 Diabetes: 17 | 74 | – | 64 | 17 | 96 |
| ANZIC 15 (n = 722) | Australia and New Zealand June –August 2009 | ICU admission† | Median (IQR): 40 years (26–54) | Asthma/COPD: 33 Diabetes: 16 | 29 | 65 | 49‡‡ | 17 | – |
| Nicolay 16 (n = 77) | Ireland July 2009–May 2010 | ICU admission‡ | Median (IQR): 43 years (30–56) | Asthma/COPD: 34 Malignancy/immunosupression: 20 | 36 | 72 | – | 18 | – |
| Pediatric studies | |||||||||
| Jouvet 17 (n = 57) | Canada April–August 2009 | Critical illness††,††† | Median (range): 5 years (0·08–17) | Asthma: 25 Neurologic disease: 23 | – | 68 | – | 7 | 77 |
| Randolph 18 (n = 838) | United States April 2009–April 2010 | ICU admission‡ | Median (range): 6 years (0–20) | Asthma: 31 Neurologic disease: 31 | – | 67 | – | 9 | 97 |
*IQR, interquartile range; SD, standard deviation; COPD, chronic obstructive pulmonary disease.
**Excludes obesity and history of smoking.
***This study, Dominguez‐Cherit, Kumar, and Miller report patients with body mass index (BMI) >30; ANZIC and Nicolay report patients with BMI >35.
†Includes confirmed pH1N1cases only.
††Defined as those (1) admitted to ICU, (2) requiring mechanical ventilation, (3) having a fraction of inspired oxygen (FIO2) greater than or equal to 60%, or (4) receiving intravenous infusion of inotropic or vasopressor medication.
†††Includes confirmed, probable, and suspected pH1N1 cases.
‡Includes confirmed and probable pH1N1 cases.
‡‡Includes patients with ARDS and viral pneumonitis.
ARDS, acute respiratory distress syndrome; pH1N1, pandemic influenza A (H1N1pdm09).