Risk for decreased cardiac output: validation of a proposal for nursing diagnosis
Renata Pereira de Melo, Marcos Ven´ıcios de Oliveira Lopes, Thelma Leite de Araujo, Lucia de
Fatima da Silva, Francisca Aline Arrais Sampaio Santos and Sue Moorhead
ABSTRACT
Aim: To verify the content validity of the nursing diagnosis risk for decreased cardiac output (RDCO).
Background: DCO is a phenomenon that is not restricted to individuals or environments that specifically focus on cardiovascular care. It is not only prevalent in cardiovascular care units, but also in post-anaesthesia units and non-cardiac care units among individuals with non-cardiogenic disorders. A significant decrease in cardiac output is a life-threatening situation, demonstrating the need for developing a risk nursing diagnosis for early intervention. The development of this diagnosis requires the construction of a diagnosis label, a definition of the diagnostic concept and the risk factors associated with the diagnosis.
Methods: The research was carried out in two methodological stages based on the Fehring diagnosis content validation model. The quantitative analysis consisted of the calculation of the weighted mean of the values attributed by experts to each risk factor, the level of agreement/disagreement between the experts regarding the operational definitions of risk factors and the index of diagnostic content validity (DCV).
Results: The label ‘risk for decreased cardiac output’ was considered representative of a nursing diagnosis defined as ‘at risk of developinga health status characterized by an insufficient quantity of blood pumped by the heart to meet physical metabolic demands’. Critical risk factors (DCV ≥ 0•7) were myocardial dysfunction (0•887), blood loss (0•875), increase in intrapericardial pressure (0•825), condition that leads to changes in cardiac rhythm and/or electrical conduction (0•812), deficient fluid volume (0•725), plasma loss (0•712), ineffective tissue perfusion (0•712) and electrolyte imbalance (0•7).
Conclusions: The research identified eight risk factors with valid content for assessment of RDCO.
Implications for nursing practice: The identification of risk factors for DCO assists nurses to intervene early and minimize the consequences of a deficient cardiac function.
Key words: Cardiac output•Nursing diagnosis•Validation studies
INTRODUCTION
Low cardiac output (LCO) is a medical term that represents a syndrome associated with myocardial dysfunction and poor systemic perfusion (Mass´e and Antonacci, 2005). According to Bumann and Speltz (1989) and Jara-Rubio et al. (2009), LCO is one of
Authors: R Pereira de Melo, RN, MSN, Doctoral Student, Federal University of Ceara´/Brazil, CAPES Scholarship, Rua Henriqueta Galeno, 1080, apto 1703,
Bairro Dionı´sio Torres, CEP 60135-420, Fortaleza, Cear´a, Brasil; M Venı´cios de Oliveira Lopes, RN, PhD, Nursing Professor, Federal University of Cear´a/Brazil, Rua
Alexandre Barau´na, 1115, Bairro: Rodolfo Te´ofilo, CEP 60430-160, Fortaleza, Ceara´, Brasil; T Leite de Araujo, RN, PhD, Nursing Professor, Federal University of Ceara´/Brazil,RuaAlexandreBara´una, 1115, Bairro: Rodolfo Teo´filo, CEP 60430-160, Fortaleza, Cear´a, Brasil; L de Fatima da Silva, RN, PhD, Nursing Professor,
State University of Ceara´/Brazil, Avenida Paranjana, 1700, Bairro: Campus do Itaperi, CEP 60000-000, Fortaleza, Ceara´, Brasil; F Aline Arrais Sampaio Santos, RN, MSN, Doctoral Student, Federal University of Ceara´/Brazil, Nursing Professor, Federal University of Maranh˜ao/Brazil, Rua 117, casa 81, 1a etapa, Bairro:
Conjunto Ceara´, CEP 60530-080, Fortaleza, Cear´a, Brasil; S Moorhead, PhD, Associate Professor, College of Nursing, the University of Iowa, 1903 West Garfield Street, Davenport, IA 52804, USA
Address for correspondence: M Venı´cios de Oliveira Lopes, RN, PhD, Nursing Professor, Federal University of Ceara´/Brazil, Rua Alexandre Bara´una, 1115,
Bairro: Rodolfo Teo´filo, CEP 60430-160, Fortaleza, Cear´a, Brasil E-mail: marcos@ufc.br
the most complex and frequently observed problems in critically ill patients and in those who have undergone cardiac surgery with cardiopulmonary bypass. A significant decrease in cardiac output is a life-threatening situation that requires nursing judgement and immediate action, corroborating the
©2011 The Authors. Nursing in Critical Care ©2011 British Association of Critical Care Nurses•Vol 16 No 6 287
Risk for decreased cardiac output
need for developing a risk nursing diagnosis for early intervention.
Clinical manifestations of LCO are determined by changes in heart rate/rhythm, preload, afterload and/or contractility. Heart rate/rhythm is controlled by the depolarization rate of the sinoatrial node, which can be modified by hormones (e.g. epinephrine, thyroxin), concentration of electrolytes in plasma, body temperature, autonomic nervous system and stretching of the atrium wall (Guyton and Hall, 2006). Preload corresponds to ventricular filling pressure at the moment of its maximum stretching and is influencedbytheventricularend-diastolicvolumeand the Frank–Starling mechanism. On the other hand, the afterload refers to blood pressure or resistance at the moment of ventricular ejection. Its values are modified according to the intraventricular pressure, ventricular diameter, wall thickness of artery, aortic compliance, peripheral vascular resistance and blood viscosity. Finally, contractility or cardiac inotropy corresponds to the force generated by myocardial muscle during systole, indirectly assessed by the left ventricular stroke workindex (GuytonandHall, 2006;Jarvis, 2008; Smeltzer and Bare, 2008).
The main signs and symptoms of LCO include intense peripheral vasoconstriction; cold, pale skin; diaphoresis; decreased capillary refill; peripheral cyanosis; decreased pulse pressure; low or inaudible non-invasive arterial pressure (systolic pressure < 90 mmHg); low urine output (<30 mL); low cardiac index (<2 L/min/m2); low mixed venous oxygen saturation (SvO2 < 50%); discrepancies between carotid or femoral and radial pulse extents; jaundice and metabolic acidosis (Adams and Antman, 2001; L´opez and Laurentys-Medeiros, 2004).
Previous studies show that LCO is not restricted to individuals or environments that demand only cardiovascularcare.Thus,itisprevalentbothinspecific units within cardiovascular care (e.g. coronary) and in units of a different nature, such as post-anaesthesia care units and non-cardiac units. Furthermore, it is also detected in individuals with non-cardiogenic disorders (Dougherty, 1985; Bumann and Speltz, 1989; Jesus et al., 1996; Veiga et al., 1996; Morton, 1997; Carvalho, 2003).
According to NANDA International (2009), the phenomenon of heart failure is called decreased cardiac output (DCO). The NANDA International classification and taxonomy contains clinically useful terminology for nurses to use and represents a tool for improving nursing communication across specialties and health care environments. Moreover, it can enhance the quality of patient assessments and clinical decisions made by nurses and guides nurses
to recognize patient/family/community needs and problems. This process allows for the selection of appropriate outcomes and interventions to meet the needs of the patient.
The taxonomic framework has three levels: domains (‘a sphere of activity, study or interest’), classes (‘a subdivision of a larger group; a division of per-sons or things by quality, rank or grade’) and nursing diagnosis concepts (‘a clinical judgment about indi-vidual, family or community responses to actual or potential health problems/life processes. It consti-tutes the basis for selection of nursing interventions to achieve the outcomes for which the nurse is respon-sible’). The nursing diagnosis of DCO is placed in the domain Activity/Rest and in the class Cardiovascu-lar/Pulmonary Responses. It is defined as ‘inadequate blood pumped by the heart to meet the metabolic demands of the body’ and related to the presence of one or more defining characteristics such as heart rate/rhythm, altered preload, afterload and/or con-tractility and behavioural/emotional changes which determine its specific signs and symptoms (NANDA International 2009).
The DCO was first suggested as a nursing diagnosis during a regular organization meeting of the North American Nursing Diagnosis Association, now called NANDA International. Its defining characteristics were developed by a group of nurses attending the Second Conference Group on the Classification of Nursing Diagnosis in the USA in 1975. In 1980, the diagnosis of DCO was accepted and added to the classification; however, its related factors were not discussed until 1982 at the Fifth Conference Group on the Classification of Nursing Diagnosis and changes weremade to its definition anddefining characteristics at that time (Dougherty 1985, 1997). No further modifications have been made since then.
The complexity and severity of the diagnosis DCO are highlighted by many studies suggesting that nurses need to carefully screen patients for signs and symptoms of DCO in clinical practice. One study found that risk for decreased cardiac output (RDCO) determined by acute myocardial infarction was one of the 25 diagnoses identified in 30 patients’ post-cardiac catheterizations (Lima et al. 2006). This study was performed based on the NANDA International taxonomy,eventhoughRDCOisnotlistedasanursing diagnosis by that classification system. Another recently developed survey described the process of assessing and validating the concept of RDCO accordingtoWalkerandAvant’smodel (Santos, 2006). Therefore, the development of a nursing diagnosis for representing RDCO is essential as it will help nurses focus on early intervention and prevention of
288 ©2011 The Authors. Nursing in Critical Care ©2011 British Association of Critical Care Nurses
Risk for decreased cardiac output
the problem. A risk nursin
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