A time-sensitive analysis of the prognostic utility of vasopressor dose in septic shock

Patients admitted in the intensive care unit after solid organ or bone marrow transplantation: Retrospective cohort study

BACKGROUND

Solid organ transplantation (SOT) and hematopoietic stem cell transplantation (HSCT) revolutionized the survival and quality of life of patients with malignant diseases, various immunologic, and metabolic disorders or those associated with a significant impairment in a patient's quality of life.

AIM

To investigate admission causes and treatment outcomes of patients after SOT or HSCT treated in a medical intensive care unit (ICU).

METHODS

We conducted a single-center, retrospective epidemiological study in the medical ICU at the University Hospital Centre Zagreb, Croatia covering the period from January 1, 2018 to December 31, 2023.

RESULTS

The study included 91 patients with either SOT [28 patients (30.8%)] or HSCT [63 patients (69.2%)]. The median age was 56 (43.2-64.7) years, and 60.4% of the patients were male. Patients with SOT had more comorbidities than patients after HSCT [χ² (5, n = 141) = 18.513, P < 0.001]. Sepsis and septic shock were the most frequent reasons for admission, followed by acute respiratory insufficiency in patients following HSCT. Survival rate significantly differed between SOT and HSCT [χ² (1, n = 91) = 21.767, P < 0.001]. ICU survival was 57% in the SOT and 12.7 % in the HSCT group. The need for mechanical ventilation [χ² (1, n = 91) = 17.081, P < 0.001] and vasopressor therapy [χ² (1, n = 91) = 36.803, P < 0.001] was associated with survival. The necessity for acute renal replacement therapy did not influence patients' survival [χ² (1, n = 91) = 0.376, P = 0.54]. In the subgroup of patients with infection, 90% had septic shock, and the majority had positive microbiological samples, mostly Gram-negative bacteria. The ICU survival of patients with sepsis/septic shock cumulatively was 15%. The survival of SOT patients with sepsis/shock was 45%.

CONCLUSION

Patients with SOT or HSCT are frequently admitted to the ICU due to sepsis and septic shock. Despite advancements in critical care, the mortality rate of patients with refractory septic shock and multiorgan failure in this patient population is extremely high. Early recognition and timely ICU admittance might improve the outcome of patients, especially after HSCT.

Early high-dose vasopressors in refractory septic shock: A cohort study

PURPOSE

Septic shock refractory to high-dose vasopressors confers unacceptably high mortality, however, the impact of timing of peak vasopressor dose exposure on outcomes is unknown.

METHODS

This retrospective cohort study included adults who required a vasopressor dose ≥0.5 μg/kg/min norepinephrine-equivalents in the first 24 h of septic shock. We used the median time to peak vasopressor dose to stratify patients into 'early' and 'late' groups. Multivariable Cox proportional hazards regression was used to assess the impact of time to peak vasopressor exposure on mortality.

RESULTS

The median time to peak vasopressor dose exposure was 6 (3,13) hours, defining the early (n = 351) and late (n = 351) groups. In the severity-adjusted multivariable analysis, the early group was less likely to die within 28 days (HR 0.76, 95 % CI 0.58-0.99). The early group experienced significantly more days alive and free from renal replacement therapy, vasopressors, mechanical ventilation, and quicker independence from vasopressors (HR 1.40, 95 % CI 1.17-1.69). Mesenteric ischemia and arrhythmias were more frequent in the late group.

CONCLUSIONS

In vasopressor-refractory septic shock, achieving the peak vasopressor dose within the first six hours of shock onset was associated with reduced mortality and more days alive and free from organ-support therapies.

Cardiovascular Subphenotypes in Acute Respiratory Distress Syndrome

OBJECTIVES

To use clustering methods on transthoracic echocardiography (TTE) findings and hemodynamic parameters to characterize circulatory failure subphenotypes and potentially elucidate underlying mechanisms in patients with acute respiratory distress syndrome (ARDS) and to describe their association with mortality compared with current definitions of right ventricular dysfunction (RVD).

DESIGN

Retrospective, single-center cohort study.

SETTING

University Hospital ICU, Birmingham, United Kingdom.

PATIENTS

ICU patients that received TTE within 7 days of ARDS onset between April 2016 and December 2021.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Latent class analysis (LCA) of TTE/hemodynamic parameters was performed in 801 patients, 62 years old (interquartile range, 50-72 yr old), 63% male, and 40% 90-day mortality rate. Four cardiovascular subphenotypes were identified: class 1 (43%; mostly normal left and right ventricular [LV/RV] function), class 2 (24%; mostly dilated RV with preserved systolic function), class 3 (13%, mostly dilated RV with impaired systolic function), and class 4 (21%; mostly high cardiac output, with hyperdynamic LV function). The four subphenotypes differed in their characteristics and outcomes, with 90-day mortality rates of 19%, 40%, 78%, and 59% in classes 1-4, respectively ( p < 0.0001). Following multivariable logistic regression analysis, class 3 had the highest odds ratio (OR) for mortality (OR, 6.9; 95% CI, 4.0-11.8) compared with other RVD definitions. Different three-variable models had high diagnostic accuracy in identifying each of these latent subphenotypes.

CONCLUSIONS

LCA of TTE parameters identified four cardiovascular subphenotypes in ARDS that more closely aligned with circulatory failure mechanisms and mortality than current RVD definitions.

Oral midodrine does not expedite liberation from protracted vasopressor infusions: A case-control study

Vasopressor dependence is a common problem affecting patients in the recovery phase of critical illness, often necessitating intensive care unit (ICU) admission and other interventions which carry associated risks. Midodrine is an orally administered vasopressor which is commonly used off-label to expedite weaning from vasopressor infusions and facilitate discharge from ICU. We performed a single-centre, case-control study to assess whether midodrine accelerated liberation from vasopressor infusions in patients who were vasopressor dependent. Cases were identified at the discretion of treating intensivists and received 20 mg oral midodrine every eight h from enrolment. Controls received placebo. Data on duration and dose of vasopressor infusion, haemodynamics and adverse events were collected. Between 2012 and 2019, 42 controls and 19 cases were recruited. Cases had received vasopressor infusions for a median of 94 h versus 29.3 h for controls, indicating prolonged vasopressor dependence amongst cases. Midodrine use in cases was not associated with faster weaning of intravenous (IV) vasopressors (26 h versus 24 h for controls, P = 0.51), ICU or hospital length of stay after adjustment for confounders. Midodrine did not affect mean heart rate but was associated with bradycardia. This case-control study demonstrates that midodrine has limited efficacy in expediting weaning from vasopressor infusions in patients who have already received relatively prolonged courses of these infusions.

Hyperdynamic Left Ventricular Ejection Fraction in ICU Patients With Sepsis

OBJECTIVES

To evaluate the cause and prognosis of hyperdynamic left ventricular ejection fraction in critically ill patients with sepsis.

DESIGN

Retrospective, single-center cohort study.

SETTING

University Hospital ICU, Birmingham, United Kingdom.

PATIENTS

ICU patients who received a transthoracic echocardiogram within 7 days of sepsis between April 2016 and December 2019.

INTERVENTION

None.

MEASUREMENTS AND MAIN RESULTS

The 90-day mortality rates of normal (55-70%), depressed (< 55%), and hyperdynamic left ventricular ejection fraction (> 70%) were compared. Multivariate logistic regression analysis was performed to determine the association of left ventricular ejection fraction phenotypes with mortality and the association of clinical variables with left ventricular ejection fraction phenotypes. One thousand fourteen patients met inclusion criteria and were 62 years old (interquartile range, 47-72), with mostly respiratory infections (n = 557; 54.9%). Ninety-day mortality was 32.1% (n = 325). Patients with hyperdynamic left ventricular ejection fraction had a higher mortality than depressed and normal left ventricular ejection fraction cohorts (58.9% [n = 103] vs 34.0% [n = 55] vs 24.7% [n = 167]; p < 0.0001, respectively). After multivariate logistic regression, hyperdynamic left ventricular ejection fraction was independently associated with mortality (odds ratio, 3.90 [2.09-7.40]), whereas depressed left ventricular ejection fraction did not (odds ratio, 0.62 [0.28-1.37]). Systemic vascular resistance was inversely associated with hyperdynamic left ventricular ejection fraction (odds ratio, 0.79 [0.58-0.95]), and age, frailty, and ischemic heart disease were associated with depressed left ventricular ejection fraction.

CONCLUSIONS

Hyperdynamic left ventricular ejection fraction was associated with mortality in septic ICU patients and may reflect unmitigated vasoplegia from sepsis. Depressed left ventricular ejection fraction was not associated with mortality but was associated with cardiovascular disease.

Cardiovascular subphenotypes in patients with COVID-19 pneumonitis whose lungs are mechanically ventilated: a single-centre retrospective observational study

Unsupervised clustering methods of transthoracic echocardiography variables have not been used to characterise circulatory failure mechanisms in patients with COVID‐19 pneumonitis. We conducted a retrospective, single‐centre cohort study in ICU patients with COVID‐19 pneumonitis whose lungs were mechanically ventilated and who underwent transthoracic echocardiography between March 2020 and May 2021. We performed latent class analysis of echocardiographic and haemodynamic variables. We characterised the identified subphenotypes by comparing their clinical parameters, treatment responses and 90‐day mortality rates. We included 305 patients with a median (IQR [range]) age 59 (49–66 [16–83]) y. Of these, 219 (72%) were male, 199 (65%) had moderate acute respiratory distress syndrome and 113 (37%) did not survive more than 90 days. Latent class analysis identified three cardiovascular subphenotypes: class 1 (52%; normal right ventricular function); class 2 (31%; right ventricular dilation with mostly preserved systolic function); and class 3 (17%; right ventricular dilation with systolic impairment). The three subphenotypes differed in their clinical characteristics and response to prone ventilation and outcomes, with 90‐day mortality rates of 22%, 42% and 73%, respectively (p < 0.001). We conclude that the identified subphenotypes aligned with right ventricular pathophysiology rather than the accepted definitions of right ventricular dysfunction, and these identified classifications were associated with clinical outcomes.