Data was collected to determine the acute changes of handgrip strength (HGS), lung function and health-related quality of life (HRQoL) in adults (≥18 years) undergoing elective cardiac surgery. Further, the data was used to examine the relationship between these variables and the predictive ability of HGS for lung function and HRQoL in these patients.
In this study, HGS, lung function and HRQoL data were collected before cardiac surgery (1-2 days) and at the point of physiotherapy discharge (5- 7 days post operation) from the hospital.
Handgrip strength assessment involved only the dominant hand. Prior to the surgery, HGS was assessed using a Jamar hydraulic hand dynamometer (Model 5030J1, Patterson Medical, Warrenville, IL) or Jamar hydraulic hand dynamometer (Model 5030J1, Performance Health, China), while the Jamar hydraulic hand dynamometer (Model 5030J1, Performance Health, China) was used to assess HGS at the time of physiotherapy discharge. Statistical differences between the dynamometers used pre-operatively were adjusted to the Jamar hydraulic hand dynamometer (Performance Health) using regression equations. Handgrip strength was assessed in line with the guidelines of the American Society of Hand Therapists and included adjustment of the dynamometer handle to the second 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 dominant HGS 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 dominant HGS.
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 the EasyOne spirometer (Model 2001, ndd Medizintechnik, Switzerland) or Vitalograph Alpha 6000 (Vitalograph Ltd, Ireland) while the Vitalograph Alpha 6000 (Vitalograph Ltd, Ireland) was used to assess lung function at the point of physiotherapy discharge. Statistical differences between the spirometers used pre-operatively were adjusted to the Vitalograph-Alpha spirometer using 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.
The HRQoL was assessed using the Short Form-36 medical outcome (SF-36) questionnaire. This tool assesses the physical component summary (PCS) and the mental component summary (MCS), 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 drinking status; socio-economic status; physical activity level via self-reported question; New York Heart Association classification; left ventricular ejection fraction; type of cardiac surgery to be undertaken; and risk of death assessment via Acute Physiology and Chronic Health Evaluation III score and the intensive care unit derived, Australian and New Zealand Risk of Death.
Data on other operative and post-operative characteristics of these patients was also obtained from their medical records. These included: aortic cross clamp time in minutes; cardiopulmonary by-pass time in minutes; ICU length of stay in days; discharge destination and total hospital length of stay in days. During post-operative assessments, patient-reported chest pain was assessed using the numerical rating scale (0 = no pain to 10 = worst pain ever) at rest and during coughing.
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). Changes in HGS, lung function and HRQoL between pre-operative and discharge assessments were examined via paired t-tests. Relationship between variables was assessed using Pearson correlation coefficients, which were categorized as weak (0.00-0.30), moderate (0.31-0.70) or strong (>0.7). Prediction of lung function and HRQoL using HGS 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: Data was collected using SPSS version 27.0 (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: Data was analysed with SPSS version 27.0 (IBM Inc, Chicago IL).