Introduction
Methods
Study design, data sources, and population
Outcomes
Predictors
Statistical analyses
Sensitivity analyses
Pregnancies with ICU admission* (n = 10,204) | Pregnancies without ICU admission* (n = 3,152,099) | Standardized difference† | |
---|---|---|---|
Delivery admissions | 9001 (88.2%) | 3,020,112 (95.8%) | − 0.28 |
Antepartum admissions | 2596 (25.4%) | 250,372 (7.9%) | 0.48 |
Postpartum admissions | 2583 (25.3%) | 58,652 (1.9%) | 0.73 |
Abortions or ectopic pregnancy-related admissions | 918 (9.0%) | 107,097 (3.4%) | 0.23 |
Age (years) (mean ± SD) | 30.5 ± 6.3 | 29.5 ± 5.6 | 0.16 |
< 15 | 8 (0.08%) | 1191 (0.04%) | 0.22 |
15–19 | 475 (4.7%) | 136,868 (4.3%) | |
20–24 | 1365 (13.5%) | 480,141 (15.3%) | |
25–29 | 2491 (24.6%) | 913,371 (29.0%) | |
30–34 | 3042 (30.0%) | 1,006,926 (32.0%) | |
35–39 | 2026 (20.0%) | 500,255 (15.9%) | |
40–44 | 653 (6.4%) | 102,423 (3.2%) | |
45+ | 81 (0.8%) | 5932 (0.2%) | |
Gestational week at delivery admission (weeks) | 36.0 ± 4.7 | 38.7 ± 2.5 | − 0.72 |
Maternal comorbidity index | 1.62 ± 2.06 | 0.47 ± 0.84 | 0.73 |
Live birth | 9005 (88.2%) | 3,020,305 (95.8%) | − 0.28 |
Singleton birth | 8535 (83.6%) | 2,970,321 (94.2%) | − 0.34 |
Twin birth | 484 (4.7%) | 51,029 (1.6%) | 0.18 |
> Triplet birth | 17 (0.2%) | 1780 (0.06%) | 0.03 |
Parity | 0.17 | ||
0 | 6598 (64.7%) | 1,829,634 (58.0%) | |
1 | 1939 (19.0%) | 818,031 (26.0%) | |
2+ | 1667 (16.3%) | 504,434 (16.0%) | |
Residence rurality (0.7% missing) | - 0.01 | ||
Urban | 8225 (81.2%) | 2,559,659 (81.8%) | |
Rural | 1907 (18.8%) | 568,117 (18.2%) | |
Residence income quintile (14.0% missing) | 0.11 | ||
Quintile 1 (lowest) | 2603 (29.3%) | 684,917 (25.3%) | |
Quintile 2 | 1929 (21.7%) | 571,796 (21.1%) | |
Quintile 3 | 1659 (18.7%) | 523,475 (19.3%) | |
Quintile 4 | 1485 (16.7%) | 493,408 (18.2%) | |
Quintile 5 (highest) | 1212 (13.6%) | 435,658 (16.1%) | |
Hospital rurality (0.6% missing) | − 0.01 | ||
Urban | 9917 (97.8%) | 3,066,345 (97.9%) | |
Rural | 224 (2.2%) | 66,429 (2.1%) | |
Delivery mode | |||
Vaginal | 2148 (21.0%) | 2,157,286 (68.4%) | − 1.08 |
Cesarean section | 4425 (43.4%) | 817,172 (25.9%) | |
Transfer to another institution for acute care | 1594 (15.6%) | 38,350 (1.2%) | 0.54 |
Readmission | 1381 (13.5%) | 42,338 (1.3%) | 0.48 |
Province or territory of admission | |||
Newfoundland and Labrador | 260 (2.5%) | 51,481 (1.6%) | 0.25 |
Prince Edward Island | 39 (0.4%) | 15,410 (0.5%) | |
Nova Scotia | 226 (2.2%) | 95,713 (3.0%) | |
New Brunswick | 298 (2.9%) | 80,163 (2.5%) | |
Ontario | 5967 (58.5%) | 1,524,080 (48.3%) | |
Manitoba | 376 (3.7%) | 181,367 (5.7%) | |
Saskatchewan | 494 (4.8%) | 158,537 (5.0%) | |
Alberta | 1177 (11.5%) | 553,741 (17.6%) | |
British Columbia | 1308 (12.8%) | 473,437 (15.0%) | |
Territories | 59 (0.6%) | 18,170 (0.6%) | |
Severe maternal morbidity (any versus none) | 5017 (49.2%) | 44,995 (1.4%) | 1.31 |
0 (number of severe maternal morbidity events) | 4588 (45.0%) | 3,106,352 (98.5%) | 1.48 |
1 | 2616 (25.6%) | 41,884 (1.3%) | |
2 | 1351 (13.2%) | 2890 (0.09%) | |
3 | 719 (7.0%) | 625 (0.02%) | |
≥ 4 | 930 (9.1%) | 348 (0.01%) | |
Length of hospital stay (days) | 11.1 ± 16.4 | 2.7 ± 3.3 | 0.71 |
Hospital mortality during episode of pregnancy care | 130 (1.3%) | 65 (0.00%) | 0.16 |
Hospital group according to hospital volume of pregnancy | |||
1 (lowest volume) | 204 (2.0%) | 19,476 (0.6%) | 0.15 |
2 | 203 (2.0%) | 66,852 (2.1%) | |
3 | 818 (8.0%) | 211,392 (6.7%) | |
4 | 2165 (21.2%) | 598,849 (19.0%) | |
5 (highest) | 6814 (66.8%) | 2,255,530 (71.6%) |
Results
Incidence and clinical characteristics of pregnancy-related ICU admissions in Canada
Individual indicator of several maternal morbidity | No. (%) of patients with the individual severe maternal morbidity indicator among the 50,012 severe maternal morbidity events | No. (%) of patients with an ICU admission with the individual severe maternal morbidity indicator | No. (%) of deaths among patients with the individual severe maternal morbidity indicator |
---|---|---|---|
Postpartum hemorrhage or transfusion | 16,364 (0.52) | 1991 (12.71) | 42 (0.26) |
Sepsis | 11,557 (0.37) | 548 (4.74) | 21 (0.18) |
Myocardial infarction, failure, arrest, or pulmonary edema | 4483 (0.14) | 1041 (23.22) | 101 (2.25) |
Placental or uterine abruption and hemorrhage | 3758 (0.12) | 285 (7.58) | 12 (0.32) |
Embolization, ligation of pelvic or uterine vessels due to hemorrhage | 3015 (0.10) | 593 (19.67) | 6 (0.20) |
Subtotal open hysterectomy | 2868 (0.09) | 347 (12.10) | 11 (0.38) |
Eclampsia | 2170 (0.07) | 467 (21.52) | 3 (0.14) |
Mechanical ventilation | 2099 (0.07) | 1933 (92.09) | 115 (5.48) |
Repair of the bladder, urethra, or intestine | 2052 (0.06) | 64 (3.12) | 1 (0.05) |
Hysterectomy and postpartum hemorrhage | 1561 (0.05) | 728 (46.64) | 16 (1.02) |
Obstetric embolism | 1404 (0.04) | 268 (19.09) | 34 (2.42) |
Placenta previa with hemorrhage or blood transfusion | 1343 (0.04) | 238 (17.72) | 4 (0.30) |
Acute renal failure | 1116 (0.04) | 443 (39.70) | 45 (4.03) |
Obstetric shock | 1124 (0.04) | 533 (47.42) | 38 (3.38) |
Cardiomyopathy in the puerperium | 1058 (0.03) | 395 (37.33) | 9 (0.85) |
Evacuation of incisional hematoma | 1037 (0.03) | 47 (4.53) | 0 (0) |
Total open hysterectomy | 822 (0.03) | 387 (47.08) | 13 (1.58) |
Acute abdomen | 790 (0.02) | 77 (9.75) | 3 (0.38) |
Intrapartum hemorrhage and blood transfusion | 736 (0.02) | 135 (18.34) | 7 (0.95) |
Cesarean hysterectomy | 724 (0.02) | 186 (25.69) | 4 (0.55) |
Acute psychosis | 694 (0.02) | 16 (2.31) | 0 (0) |
Pulmonary, cardiac, and central nervous system complications of anesthesia | 390 (0.01) | 67 (17.18) | 3 (0.77) |
Cerebrovascular diseases: subarachnoid and intracranial hemorrhage, cerebral infarction, stroke | 331 (0.01) | 166 (50.15) | 30 (9.06) |
Disseminated intravascular coagulation | 281 (0.01) | 192 (68.33) | 14 (4.98) |
Adult respiratory distress syndrome | 252 (0.01) | 192 (76.19) | 12 (4.76) |
Dialysis | 202 (0.01) | 128 (63.37) | 22 (10.89) |
Hepatic failure | 114 (0.00) | 53 (46.49) | 14 (12.28) |
Cerebral venous thrombosis | 111 (0.01) | 29 (26.13) | 3 (2.70) |
Sickle cell anemia with crisis | 111 (0.01) | 8 (7.21) | 0 (0) |
Status epilepticus | 101 (0.00) | 43 (42.57) | 0 (0) |
Status asthmaticus | 76 (0.00) | 6 (7.89) | 1 (1.32) |
Coma | 64 (0.00) | 37 (57.81) | 6 (9.38) |
Death† | 41 (0.00) | 8 (19.51) | 16 (39.02) |
Hospital volume of pregnancy admission
Multi-level logistic regression models
Variable | Odds ratio (95%CI) |
---|---|
Patient variables | |
Maternal comorbidity index | 1.88 (1.86–1.99) |
Age (years) | |
< 15 | 1.73 (0.76–3.91) |
15–19 | 1.11 (1.00–1.25) |
20–24 | Reference |
25–29 | 1.04 (0.97–1.12) |
30–34 | 1.19 (1.11–1.28) |
35–39 | 1.49 (1.38–1.61) |
40–44 | 2.22 (2.00–2.48) |
> 44 | 2.91 (2.24–3.78) |
Parity | 0.78 (0.76–0.81) |
Residence (urban/rural) | 1.09 (1.02–1.16) |
Transfer between hospitals | 13.94 (12.1–13.83) |
Income quintile | |
1 (lowest) | 1.44 (1.34–1.55) |
2 | 1.28 (1.20–1.39) |
3 | 1.20 (1.10–1.28) |
4 | 1.12 (1.03–1.21) |
5 (highest) | Reference |
Hospital variables | |
Hospital (urban versus rural) | 1.30 (0.94–1.79) |
Groups according to hospital volume of pregnancy | |
1 (lowest volume) | 12.94 (12.10–13.83) |
2 | Reference |
3 | 1.36 (1.00–1.86) |
4 | 1.51 (1.10–2.07) |
5 (highest volume) | 1.32 (0.96–1.80) |
Province | |
Newfoundland and Labrador | 1.20 (0.76–1.89) |
Prince Edward Island | 0.50 (0.18–1.39) |
Nova Scotia | 0.70 (0.44–1.13) |
New Brunswick | 0.64 (0.41–1.02) |
Ontario | Reference |
Manitoba | 0.32 (0.21–0.48) |
Saskatchewan | 0.60 (0.41–0.87) |
Alberta | 0.35 (0.27–0.46) |
British Columbia | 0.48 (0.37–0.62) |
Territories | 0.37 (0.11–1.23) |
Variability
Sensitivity analyses
Discussion
Question | |
• Is there variability of ICU admission practices for pregnant and postpartum women in Canadian hospitals and what is the association between patient and hospital characteristics and ICU admission practices? | |
Findings | |
• In this nationwide population-based cohort study of 342 acute care hospitals with 3.1 million pregnancies in Canada, there were 3.2 ICU admissions per 1000 pregnancies with provincial variation. • More comorbidities, urban residence, and lower incomes were associated with ICU admission. • In comparison with the maternal comorbidity index = 0, increasing maternal comorbidity index has higher odds of admitting to ICU (index = 1, odds ratio 1.90; index = 2 or higher, odds ratio 8.67). • Median odds ratio of ICU admission among Canadian pregnant women was 1.92, which demonstrated for two pregnant women with similar characteristics at different hospitals; the median odds of being admitted to ICU in one hospital compared to another was 1.92. • Given the fact that only two thirds of all women who subsequently died were admitted to ICU, these happened to those who were less sick at the time of hospital admission and less likely to transfer to another institution for acute care, but more likely to develop a life-threatening condition in urban hospitals, compared to maternal death with ICU admission. | |
Meaning | |
• There is a substantial variability in admission patterns to intensive care for pregnant and postpartum women in Canadian hospitals. |
Studies | Study period | Study sites (country) | No. of pregnancy-related ICU patients | ICU admission rate | Mortality (per 100,000 cases) | Variability of ICU admission rate among hospitals |
---|---|---|---|---|---|---|
Harrison 2005 | 1995–2003 | UK | 1902 | 9.0 per 1000 ICU admissions | Hospital mortality (26 per 100,000 all ICU admissions, 3049 per 100,000 pregnancy-related ICU admissions) | Not described |
Madan 2009 | 1997–2005 | NJ, USA | 15,447 | 15.4 per 1000 pregnancies | Hospital mortality (12 per 100,000 pregnancies, 149 per 100,000 pregnancy-related ICU admissions) | Not described |
Wanderer 2013 | 1999–2008 | MD, USA | 2927 | 4.1 per 1000 pregnancies | Hospital mortality (7.6 per 100,000 pregnancies, 1810 per 100,000 pregnancy-related ICU admissions) | Not described |
Chantry 2015 | 2006–2009 | France | 11,824 | 3.6 per 1000 pregnancies | ICU mortality (4.7 per 100,000 pregnancies, 1294 per 100,000 pregnancy-related ICU admissions) | Not described |
Oud 2017 | 2001–2010 | TX, USA | 158,410 | 39 per 1000 pregnancies | Hospital mortality (10 per 100,000 pregnancies, 261 per 100,000 pregnancy-related ICU admissions) | Not described* |
Aoyama 2019 | 2004–2015 | Canada | 10,204 | 3.2 per 1000 pregnancies | Hospital mortality (6.2 per 100,000 pregnancies, 1274 per 100,000 pregnancy-related ICU admissions) | MOR 1.92 |