Measuring cardiac output at the bedside

Decreased cardiac output: an integrative review

OBJECTIVE

to identify, in the scientific literature, the defining characteristics and contributing factors (related factors, associated conditions and populations at risk) for nursing diagnosis decreased cardiac output.

METHOD

an integrative literature review, conducted between September and October 2020, with an update in March 2022, in the MEDLINE via PubMed, LILACS, SciELO, CINAHL and EMBASE databases. Using acronym PEO, studies published in the last 10 years in Portuguese, English and Spanish were included. A descriptive analysis was carried out to present the elements mapped in the literature.

RESULTS

analysis of 31 articles identified different elements, highlighting 4 new related factors: hyperglycemic stress, prone position, left lateral position, sleep deprivation. Individuals with a history of cardiovascular disease and males were identified as possible populations at risk.

FINAL CONSIDERATIONS

the elements for decreased cardiac output, identified in the literature, add evidence that justifies the permanence of this diagnosis in the NANDA-I classification.

Débito cardíaco diminuído: revisão integrativa

RESUMO Objetivo: identificar, na literatura científica, as características definidoras e fatores contribuintes (fatores relacionados, condições associadas e populações em risco) para o diagnóstico de enfermagem débito cardíaco diminuído. Método: revisão integrativa da literatura, conduzida entre setembro e outubro de 2020, com atualização em março de 2022, nas bases de dados MEDLINE via PubMed, LILACS, SciELO, CINAHL e EMBASE. Com uso do acrônimo PEO, foram incluídos estudos publicados nos últimos 10 anos em português, inglês e espanhol. Realizouse análise descritiva para apresentar os elementos mapeados na literatura. Resultados: análise de 31 artigos identificou diferentes elementos, com destaque para 4 novos fatores relacionados: estresse hiperglicêmico, posição prona, posição lateral esquerda, privação do sono. Indivíduos com história de doença cardiovascular e do sexo masculino foram apontados como possíveis populações em risco. Considerações finais: os elementos para débito cardíaco diminuído, identificados na literatura, agregam evidências que justificam a permanência desse diagnóstico na classificação da NANDA-I.

Left ventricular-arterial coupling as a predictor of stroke volume response to norepinephrine in septic shock - a prospective cohort study

Background

Left ventricular-arterial coupling (VAC), defined as the ratio of arterial elastance (Ea) to left ventricular end-systolic elastance (Ees), is a key determinant of cardiovascular performance. This study aims to evaluate whether left VAC can predict stroke volume (SV) response to norepinephrine (NE) in septic shock patients.

Methods

This was a prospective cohort study conducted in an intensive care unit of a tertiary teaching hospital in China. We recruited septic shock patients who had persistent hypotension despite fluid resuscitation and required NE to maintain mean arterial pressure (MAP) > 65 mmHg. Those patients in whom the target MAP was not reached after NE infusion were ineligible. Echocardiographic variables were measured before (baseline) and after NE infusion. SV responder was defined by a ≥ 15% increase in SV after NE infusion.

Results

Of 34 septic shock patients included, 19 (56%) were SV responders. Before NE infusion, SV responders had a lower Ees (1.13 ± 0.24 mmHg/mL versus 1.50 ± 0.46 mmHg/mL, P = 0.005) and a higher Ea/Ees ratio (1.47 ± 0.40 versus 1.02 ± 0.30, P = 0.001) than non-responders, and Ea in SV responders was comparable to that in non-responders (1.62 ± 0.36 mmHg/mL versus 1.43 ± 0.28 mmHg/mL, P = 0.092). NE significantly increased Ea and Ees in both groups. The Ea/Ees ratio was normalized by NE administration in SV responders but unchanged in non-responders. The baseline Ea/Ees ratio was positively correlated with NE-induced SV increases (r = 0.688, P < 0.001). Logistic regression analysis indicated that the baseline Ea/Ees ratio was a predictor of SV increases induced by NE (odd ratio 0.008, 95% confidence interval (CI): 0.000 to 0.293), with an area under the receiver operating characteristic curve of 0.816 (95% CI: 0.646 to 0.927).

Conclusions

The left VAC has the ability to predict SV response to NE infusion in septic shock patients.

Trial registration

Chinese Clinical Trial Registry, ChiCTR1900024031, Registered 23 June 2019 - Retrospectively registered, http://www.chictr.org.cn/edit.aspx?pid=40359&htm=4.