Introduction: Data was collected to determine the recovery of lung function, dominant handgrip strength (DHGS) and health-related quality of life (HRQoL) in cardiac patients at six-weeks and six-months after cardiac surgery. Further, the data was used to examine the relationship between these variables and the predictive ability of DHGS for lung function and HRQoL in these patients at these timepoints. In this data set, lung function, DHGS and HRQoL were assessed one or two days before cardiac surgery, at six-weeks and at six-month after cardiac surgery.
Dominant handgrip strength assessment: Before the surgery, DHGS was assessed using a calibrated Jamar hydraulic dynamometer (i.e. Model 5030J1, Patterson Medical, Warrenville, IL; Model 5030J1, Performance Health, China), while follow-up assessments were conducted using a similar and calibrated hand dynamometer (i.e. Model 5030J1, Performance Health; Model J00105, Sammons Preston, Bolingbrook, IL; Model EH101, Zhongshan Camry Electronic Co., Ltd, China). All DHGS results were normalised to a Jamar hydraulic dynamometer (Model 5030J1, Performance Health, China) via unique regression equations. Dominant handgrip strength was assessed in line with the guidelines of the American Society of Hand Therapists and included adjustment of the Jamar dynamometer handle to the second handle position, while the Camry dynamometer was adjusted to the third handle position. Patients were seated with hips and knees in 90 degrees while the feet rested flat on the ground, shoulders were adducted while the elbows were flexed to 90 degrees. Patients completed three DHGS trials to achieve a grip phase of six seconds and a rest phase of at least 15 seconds per trial. The highest value of the three trials was recorded as maximal DHGS.
Lung function assessment: Lung function assessment involved three indices: forced expiratory volume in one second (FEV1); forced vital capacity (FVC) and peak expiratory flow rate (PEFR). Prior to surgery, lung function was assessed using using a calibrated spirometer (i.e. Vitalograph Alpha 6000, Vitalograph Ltd, Ireland; EasyOne Model 2001, NDD Medical Technologies, Switzerland) while follow-up assessments were conducted using a calibrated spirometer (i.e. Vitalograph Alpha 6000; Microlab CareFusion, Yorba Linda, CA; CONTEC-SP10 Model, CONTEC Medical systems Ltd, China). All spirometry results were normalised to a reference device (Vitalograph Alpha 6000, Vitalograph Ltd, Ireland) via unique regression equations. During the assessment, patients adopted a seated position, applied a nose clip, inhaled fully and rapidly, and then forcefully and maximally exhaled through a disposable mouthpiece with verbal encouragement. Repeatability and acceptability criteria as per the American Thoracic Society/European Respiratory Society were applied to the FVC and FEV1 with the highest values of FVC, FEV1 and PEFR used for analyses.
Health-related quality of life assessment: The HRQoL was assessed using the Short Form-36 medical outcome (SF-36) questionnaire. This tool assesses the physical component summary and the mental component summary, which range from 0 to 100, with scores greater than 50 representing better HRQoL. Further, demographic data and clinical characteristics of the patients were obtained from their medical records to describe the patients' current health and functional level. These included: age; sex; body mass index, ethnicity, smoking and alcohol consumption status, highest education attained, employment status, and self-reported physical activity level. Clinical characteristics noted were pre-existing comorbidities, type of scheduled cardiac surgery, New York Heart Association classification, aortic cross clamp time in minutes, cardiopulmonary by-pass time in minutes, left ventricular ejection fraction, Acute Physiology and Chronic Health Evaluation III score, and the intensive care unit derived, Australian and New Zealand Risk of Death.
Data Analysis: Normality of data was checked using the Kolmogorov-Smirnov test and Lilliefors correction. All results were presented as frequency or mean (standard deviation). Recovery of lung function, DHGS and HRQoL at six-weeks and six-months was analysed using the repeated measures analysis of variance with Bonferroni correction applied for post-hoc multiple comparisons. Relationship between variables were assessed using Pearson correlation coefficients, while prediction of lung function and HRQoL using the DHGS and demographic/operative characteristics was determined using the stepwise multiple regression analysis. Level of significance was set at <0.05.
Software/equipment used to create/collect the data: IBM SPSS VERSION 27 (IBM Inc, Chicago IL). Variable labels and data coding are explained in the variable view of the attached SPSS file.
Software/equipment used to manipulate/analyse the data: IBM SPSS VERSION 27 (IBM Inc, Chicago IL).