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Author Spotlight: Unraveling the Impact of Mechanical Ventilation on Diaphragm Function and Patient Outcomes
Published on: November 3, 2023
Persistent diaphragm dysfunction after cardiac surgery is associated with adverse respiratory outcomes: a prospective
Driss Laghlam1,2, Cecile Naudin3, Alexandre Srour4
1Department of Cardiology and Critical Care, Neuilly-sur-Seine, France. driss.laghlam@gmail.com.
Insights
Persistent diaphragm dysfunction occurs in 8% of patients after cardiac surgery and is linked to worse respiratory outcomes, including longer ventilation times and higher pneumonia rates. This highlights the importance of monitoring diaphragm function post-surgery.
Area of Science:
- Medical research
- Pulmonology
- Cardiothoracic surgery
Background:
- Transient diaphragm dysfunction is frequent post-cardiac surgery.
- Data on persistent diaphragm dysfunction (PDD) incidence, risk factors, and outcomes are limited.
Purpose of the Study:
- To determine the incidence, risk factors, and outcomes of PDD after elective cardiac surgery.
- To evaluate diaphragm function using ultrasound.
Main Methods:
- Prospective cohort study of 122 adult patients undergoing elective cardiac surgery.
- Diaphragm function assessed via ultrasound (M-mode) preoperatively and post-seventh day.
- PDD defined by reduced diaphragm excursion post-seventh day.
Main Results:
- 8% of patients (10/122) exhibited PDD.
- No specific risk factors for PDD were identified.
- PDD correlated with increased mechanical ventilation duration, reintubation rates, pneumonia incidence, and ICU length of stay.
Conclusions:
- The incidence of PDD after elective cardiac surgery is 8%.
- PDD is associated with adverse respiratory outcomes and prolonged ICU stays.
Background:
Transient diaphragm dysfunction is common during the first week after cardiac surgery; however, the precise incidence, risk factors, and outcomes of persistent diaphragm dysfunction are not well described.
Methods:
In a single-centre prospective cohort study, we included all consecutive patients over 18 yr who underwent elective cardiac surgery. Diaphragm function was evaluated with ultrasound (M-mode) by recording the excursion of both hemidiaphragms at two different time points: preoperatively and after the seventh postoperative day in patients breathing without assistance. Significant diaphragm dysfunction after the seventh day of the index cardiac surgery was defined as a decrease in diaphragm excursion below the lower limit of normal: at rest, < 9 mm for women and < 10 mm for men; after a sniff test, < 16 mm for women and < 18 mm for men.
Results:
Overall, 122 patients were included in the analysis. The median [interquartile range (IQR)] age was 69 [59-74] years and 96/122 (79%) were men. Ten (8%) patients had diaphragm dysfunction after the seventh postoperative day. We did not identify risk factors for persistent diaphragm dysfunction. Persistent diaphragm dysfunction was associated with a longer median [IQR] duration of noninvasive (8 [0-34] vs 0 [0-0] hr; difference in medians, 8 hr; 95% confidence interval [CI], 0 to 22; P < 0.001) and invasive mechanical ventilation (5 [3-257] vs 3[2-4] hr; difference in medians, 2 hr; 95% CI, 0.5 to 41; P = 0.008); a higher reintubation rate (4/10, 40% vs 1/112, 0.9%; relative risk, 45; 95% CI, 7.1 to 278; P < 0.0001), a higher incidence of pneumonia (4/10 [40%] vs 7/112 [6%]; relative risk, 6; 95% CI, 2 to 16; P < 0.001), and longer median [IQR] length of stay in the intensive care unit (8 [5-29] vs 4 [2-6] days; difference in medians, 4 days; 95% CI, 2 to 12; P = 0.002).
Conclusion:
The incidence of persistent diaphragm dysfunction was 8% in patients undergoing elective cardiac surgery and was associated with adverse respiratory outcomes.
Study Registration:
ClinicalTrials.gov (NCT04276844); prospectively registered 19 February 2020.
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