Impact of Obesity on Intensive Care Unit Resource Utilization After Cardiac Operations

Physical and respiratory therapy in the critically ill patient with obesity: a narrative review

Obesity has become increasingly prevalent in the intensive care unit, presenting a significant challenge for healthcare systems and professionals, including rehabilitation teams. Caring for critically ill patients with obesity involves addressing complex issues. Despite the well-established and safe practice of early mobilization during critical illness, in rehabilitation matters, the diverse clinical disturbances and scenarios within the obese patient population necessitate a comprehensive understanding. This includes recognizing the importance of metabolic support, both non-invasive and invasive ventilatory support, and their weaning processes as essential prerequisites. Physiotherapists, working collaboratively with a multidisciplinary team, play a crucial role in ensuring proper assessment and functional rehabilitation in the critical care setting. This review aims to provide critical insights into the key management and rehabilitation principles for obese patients in the intensive care unit.

Impact of Oxygen Saturation on Mortality in Obese and Non-obese Critically Ill Patients With Mechanical Ventilation: A Retrospective Observational Study

Background

The main aim of this study was to evaluate the effect of oxygen saturation on mortality in critically ill patients with mechanical ventilation according to obesity status.

Methods

We conducted an observational study in mechanically ventilated patients admitted to the ICU retrospectively. Demographic, arterial blood gas, ventilator setting, interventions, and peripheral oxygen saturation (Spo₂) during the first 24 h were recorded and analyzed between non-obese and obese patients. The main exposure included Spo₂, time-weighted mean Spo₂ (TWM-Spo₂), and proportion of time spent in different Spo₂ (PTS-Spo₂) levels. The primary outcome was hospital mortality. We used multivariable logistic regression models to assess the relationship between Spo₂ and mortality, as well as the interaction between PTS-Spo₂ and obesity status.

Results

A total of 25,100 patients were included, of which 10,564 (42%) were obese patients. After adjusting for confounders, compared with TWM-Spo₂ of 94–98%, TWM-Spo₂ of < =88% (OR 3.572; CI [2.343, 5.455]; p < 0.001) and of 89–93% (OR 1.514; CI [1.343, 1.706]; p < 0.001) were both associated with higher risk of mortality. PTS-Spo₂ of 99–100% was associated with increased risk of mortality for obese patients (OR 1.028; 95% CI 1.010–1.046; p = 0.002; P_{interaction =} 0.001), while PTS-Spo₂ of 89–93% was associated with increased risk of mortality (OR 1.089; 95% CI 1.051–1.128; p < 0.001; P_{interaction =} 0.001) for non-obese patients.

Conclusions

For obese and non-obese critically ill patients with mechanical ventilation, the impact of oxygen saturation on hospital mortality is different.

Robotic mitral valve operations can be safely performed in obese patients

INTRODUCTION

Robotic cardiac surgery offers mitigated risks for obese patients requiring mitral valve surgery. We aimed to study the safety of robotic mitral surgery in the obese patient population by analyzing the outcomes of mitral surgery patients in our center for robotic cardiac surgery.

METHOD

This study retrospectively included 123 consecutive patients who underwent robotic mitral valve operations in a single center for robotic cardiac surgery. Patients with body mass index (BMI) ≥ 30 were compared against patients with BMI < 30 for demographic and operative parameters as well as postoperative outcomes.

RESULTS

Mean BMI was 33.9 ± 2.8 in the obesity group (n = 87) and 25.4 ± 2.7 in the no-obesity group (n = 36). Female gender (80.6% vs. 52.9%, p = .004), diabetes (25.0% vs. 10.3%, p = .036), and hypertension (48.6% vs. 26.4%, p = .018) were more common in patients with obesity. The obesity group was operated with similar cardiopulmonary bypass and total operative times with the no-obesity group. Postoperative drainage and blood transfusion requirements were similar between the groups. Mechanical ventilation times (6.1 ± 2.2 vs. 8.0 ± 4.4 h, p = .003) and intensive care unit stay (20.4 ± 1.6 vs. 29.4 ± 3.7, p = .027) were shorter in the obesity group. Other postoperative outcomes of infection, atrial fibrillation, hospital stay duration, and readmission rates were similar between the groups.

CONCLUSION

Robotic mitral surgery is safe to perform in obese patients. Obesity should not be a contraindication for robotic mitral surgery as obese patients have outcomes similar to nonobese patients despite increased challenges and risk-factors.

The Obesity Paradox in the Trauma Patient: Normal May not Be Better

Objective

The obesity paradox is the association of increased survival for overweight and obese patients compared to normal and underweight patients, despite an increased risk of morbidity. The obesity paradox has been demonstrated in many disease states but has yet to be studied in trauma. The objective of this study is to elucidate the presence of the obesity paradox in trauma patients by evaluating the association between BMI and outcomes.

Methods

Using the 2014–2015 National Trauma Database (NTDB), adults were categorized by WHO BMI category. Logistic regression was used to assess the odds of mortality associated with each category, adjusting for statistically significant covariables. Length of stay (LOS), ICU LOS and ventilator days were also analyzed, adjusting for statistically significant covariables.

Results

A total of 415,807 patients were identified. Underweight patients had increased odds of mortality (OR 1.378, p < 0.001 95% CI 1.252–1.514), while being overweight had a protective effect (OR 0.916, p = 0.002 95% CI 0.867–0.968). Class I obesity was not associated with increased mortality compared to normal weight (OR 1.013, p = 0.707 95% CI 0.946–1.085). Class II and Class III obesity were associated with increased mortality risk (Class II OR 1.178, p = 0.001 95% CI 1.069–1.299; Class III OR 1.515, p < 0.001 95% CI 1.368–1.677). Hospital and ICU LOS increased with each successive increase in BMI category above normal weight. Obesity was associated with increased ventilator days; Class I obese patients had a 22% increase in ventilator days (IRR 1.217 95% CI 1.171–1.263), and Class III obese patients had a 54% increase (IRR 1.536 95% CI 1.450–1.627).

Conclusion

The obesity paradox exists in trauma patients. Further investigation is needed to elucidate what specific phenotypic aspects confer this benefit and how these can enhance patient care.

Level of evidence

Level III, prognostic study

The relationship between obesity and nursing care problems in intensive care patients in Austria

OBJECTIVES

To describe the characteristics and nursing care problems of intensive care patients in Austria stratified by obesity.

BACKGROUND

Obese people in intensive care units (ICUs) present nurses with special challenges. Therefore, nurses need to receive education and training regarding how to treat obese patients to provide them with the best care. Most studies on obesity in ICU patients have not specifically addressed the problems and challenges from the nurses' perspective. This may be because nursing science programmes in Europe rarely introduce the topic of obesity.

DESIGN

This was a secondary data analysis of a longitudinal study.

METHODOLOGY

The "Nursing Quality Measurement 2.0" is the Austrian version of the "International Prevalence Measurement of Care problems". It is an annual cross-sectional study, which has been carried out since 2009. Data from all ICU patients for 2009 to 2018 were extracted and combined into one file (n = 460). The main outcome measures were obesity and various nursing care problems, including care dependency.

RESULTS

Of the ICU patients. 25% were obese. Obese ICU patients suffered significantly more often from diabetes mellitus and endocrine, nutritional, or metabolic diseases than non-obese patients. About 30% of the ICU patients were totally care dependent, and 85.6% of the ICU patients were at risk of developing pressure ulcers, whereas the risk was higher for non-obese than obese patients. ICU patients with a risk of pressure ulcer (measured with the Braden Scale) had a reduced risk of being obese (OR = 0.544).

CONCLUSION

Overall, the prevalence of nursing care problems found in this study was high. No significant differences in the prevalence of nursing care problems between obese and non-obese patients were found. However, because of the increase in the number of obese patients in all nursing settings, a stronger focus on obesity research in the area of nursing science is recommended.

Impact on cardiac surgery volume of a comprehensive partnership with Integrated Health Solutions

Background

The New Brunswick Heart Centre (NBHC) entered a contractual partnership with Integrated Health Solutions (IHS) to help address increasing wait times in the province of New Brunswick.

Methods

Team leaders were identified from each of the target areas, including surgeons, anesthesiologists, nurses (operating room, intensive care unit [ICU] and postoperative ward), access coordinators and administrators. The methodology used was based on Lean principles and involved exercises by stakeholders aimed at identifying opportunities for improvement. A weekly dashboard was created to monitor and facilitate improvement efforts. No additional hospital beds or operating room theatres were added during the study period.

Results

After 2 years, the annual number of cardiac surgical interventions increased from 788 to 873, representing a 10.8% increase in capacity. The best median wait time for patients decreased from 52 to 35 days (35% reduction). The best 90th percentile wait time decreased from 126 to 98 days (22% reduction). The overall increase in capacity could be explained in part by the significant increase in fast tracking from the ICU to the ward (> 2-fold) or bypassing the ICU altogether (4-fold increase reaching 13%). Despite these successes, challenges persist as the number of OR cancellations remained around 7.5% of all cases, mainly because of limited ICU resources.

Conclusion

The NBHC-IHS partnership on this project has resulted in excellent engagement by stakeholders and promoted team cohesiveness. Furthermore, it has allowed significant reorganization and realignment of efforts to limit wait times and maximize overall capacity.

Serum GDF15, a Promising Biomarker in Obese Patients Undergoing Heart Surgery

Background: Obesity is a risk factor that negatively impacts outcomes in patients undergoing heart surgery by mechanisms that are not well-defined nor predicated on BMI alone. This knowledge gap has fuelled a search for biomarkers associated with cardiovascular diseases that could provide clinical insight to surgeons. One such biomarker is growth differentiation factor15(GDF15), associated with inflammation, metabolism, and heart failure outcomes but not yet examined in the context of obesity and cardiac surgery outcomes.

Methods: Patients undergoing open-heart surgery were consented and enrolled for blood and tissue (atria) sampling at the time of surgery. Biomarker analysis was carried out using ELISA and western blot/qPCR, respectively. Biomarker screening was classified by inflammation(NLR, GDF15, Galectin3, ST2, TNFR2), heart failure(HF)/remodeling(NT-proBNP) and metabolism(glycemia, lipid profile). Patients were categorized based on BMI: obese group (BMI ≥30.0) and non-obese group(BMI 20.0–29.9). Subsequent stratification of GDF15 high patients was conservatively set as being in the 75th percentile.

Results: A total of 80 patients undergoing any open-heart surgical interventions were included in the study. Obese (mean BMI = 35.8, n = 38) and non-obese (mean BMI = 25.7, n = 42) groups had no significant differences in age, sex, or co-morbidities. Compared to other biomarkers, plasma GDF15 (mean 1,736 vs. 1,207 ng/l, p < 0.001) was significantly higher in obese patients compared to non-obese. Plasma GDF15 also displayed a significant linear correlation with BMI (R² = 0.097; p = 0.0049). Atria tissue was shown to be a significant source of GDF15 protein and tissue levels significantly correlated with plasma GDF15 (R² = 0.4, p = 0.0004). Obesity was not associated with early/late mortality at median follow-up >2years. However, patients with high GDF15 (>1,580 ng/l) had reduced survival (65%) compared to the remaining patients with lower GDF15 levels (95%) by Kaplan Meier Analysis (median >2 years; p = 0.007).

Conclusions: Circulating GDF15 is a salient biomarker likely sourced from heart tissue that appears to predict higher risk obese patients for adverse outcomes. More importantly, elevated GDF15 accounted for more sensitive outcome association than BMI at 2 years post-cardiac surgery, suggesting it heralds links to pathogenicity and should be actively studied prospectively and dynamically in a post-operative follow-up.

Trial number: NCT03248921.

The impact of obesity on outcomes in patients receiving extracorporeal life support

Extracorporeal life support (ECLS) has been increasingly utilized to manage cardiac and pulmonary dysfunction. The impact of obesity on outcomes of ECLS is poorly defined. The purpose of the study was to compare in-hospital mortality, resource use, complications, and readmissions in obese versus non-obese patients receiving ECLS. We performed a retrospective cohort study of all adult ECLS patients with and without an obesity diagnosis using the 2010-2016 Nationwide Readmissions Database (NRD). Mortality, length of stay (LOS), hospital charges, complications, and readmissions were evaluated using multivariable logistic and linear regression. Of 23 876, patients who received ECLS, 1924 (8.1%) were obese. Obese patients received ECLS more frequently for respiratory failure (29.5% vs. 23.7%, P = .001). After adjustment for patient and hospital factors, obesity was not associated with increased odds of mortality (AOR = 1.06, P = .44) and was associated with decreased LOS (13.7 vs. 21.2 days, P < .001), hospital charges ($171 866 vs. $211 445, P < .001), and 30-day readmission (AOR = 0.71, P = .03). Obesity was also associated with reduced odds of hemorrhage (AOR = 0.43, P < .001), neurologic complications (AOR = 0.55, P = .004), and acute kidney injury (AOR=0.83, P = .04). After stratification by ECLS indication, obesity remained predictive of shorter LOS (AOR range: 0.53-0.78, all P < .05 ) and did not impact mortality (all P > .05). Respiratory support remains the most common indication for ECLS among obese patients. Among all patients, as well as by individual ECLS indication, obesity was not associated with increased odds of mortality. These findings suggest that obesity should not be considered a high-risk contraindication to ECLS.

Male patients with diabetes undergoing coronary artery bypass grafting have increased major adverse cerebral and cardiovascular events

OBJECTIVES

The role of body mass index (BMI) in the prognosis of patients with diabetes undergoing coronary artery bypass grafting (CABG) has been of great interest for a long time. However, the precise relationship between BMI and major adverse cerebral and cardiovascular events (MACCEs) in these patients is still unclear. The goal of this study was to investigate the outcome of patients with diabetes with different BMIs undergoing CABG and the results from the 5-year follow-up.

METHODS

This study included 771 patients with diabetes undergoing CABG from 1 January 2003 to 31 December 2009. They were classified based on the Chinese standard for BMI as follows: underweight: <18.5 kg/m2; normal weight: 18.5-23.9 kg/m2; overweight: 24-27.9 kg/m2; and obese: >28 kg/m2. Short-term outcomes and 5-year MACCEs were compared among various BMI groups after surgery.

RESULTS

Obese and overweight patients with diabetes tended to be younger than normal weight patients [57 years (49-64) vs 62 years (54-68) and 64 years (59-69); P < 0.001]. There were fewer male patients (25.20% vs 17.78% and 16.54%, P = 0.041). More smokers were in the 2 groups (38.8% vs 51.55% and 57.14%, P < 0.001). Glucose concentration was highest in the overweight group [6.40 (5.40-7.80) vs 6.96 (5.69-8.22) and 6.80 (5.90-8.40); P = 0.041)]. Cox regression analysis of the 5-year follow-up data indicated that various BMI groups were not associated with significant differences in 5-year MACCEs; however, male sex was the risk factor for MACCEs (hazard ratio 1.83, 95% confidence interval 1.11-3.04; P = 0.019).

CONCLUSIONS

The BMI of the patients with diabetes undergoing CABG had no effect on MACCEs. Male sex was the risk factor in these patients.

Obesity in the critically ill: a narrative review

The World Health Organization defines overweight and obesity as the condition where excess or abnormal fat accumulation increases risks to health. The prevalence of obesity is increasing worldwide and is around 20% in ICU patients. Adipose tissue is highly metabolically active, and especially visceral adipose tissue has a deleterious adipocyte secretory profile resulting in insulin resistance and a chronic low-grade inflammatory and procoagulant state. Obesity is strongly linked with chronic diseases such as type 2 diabetes, hypertension, cardiovascular diseases, dyslipidemia, non-alcoholic fatty liver disease, chronic kidney disease, obstructive sleep apnea and hypoventilation syndrome, mood disorders and physical disabilities. In hospitalized and ICU patients and in patients with chronic illnesses, a J-shaped relationship between BMI and mortality has been demonstrated, with overweight and moderate obesity being protective compared with a normal BMI or more severe obesity (the still debated and incompletely understood "obesity paradox"). Despite this protective effect regarding mortality, in the setting of critical illness morbidity is adversely affected with increased risk of respiratory and cardiovascular complications, requiring adapted management. Obesity is associated with increased risk of AKI and infection, may require adapted drug dosing and nutrition and is associated with diagnostic and logistic challenges. In addition, negative attitudes toward obese patients (the social stigma of obesity) affect both health care workers and patients.

Impact of Obesity on Postoperative Outcomes following cardiac Surgery (The OPOS study): rationale and design of an investigator-initiated prospective study

INTRODUCTION

Increasing levels of obesity worldwide have led to a rise in the prevalence of obesity-related complications including cardiovascular risk factors such as diabetes, hypertension and dyslipidaemia. Healthcare providers believe that overweight and obese cardiac surgery patients are more likely to experience adverse postoperative outcomes. The body mass index (BMI) is the primary measure of obesity in clinical practice, without accounting for a patient's level of cardiopulmonary fitness or muscle mass. The objective of this study is to determine whether fitness capacity of obese cardiac surgical patients and biomarkers, alone or in combination, will help identify patients at risk for adverse outcomes when undergoing cardiac surgery.

METHODS AND ANALYSIS

Patients between the ages of 18 and 75 years undergoing elective cardiac surgery are consented to participate in this prospective observational study. Patients will be invited to participate in measures of obesity, functional capacity and exercise capacity assessments, quality of life questionnaires, and blood and tissue sampling for biomarker analysis. The endpoints evaluated are measures other than BMI that could be predictive of short-term and long-term postoperative outcomes. Clinical outcomes of interest are prolonged ventilation, hospital length of stay, renal failure and all-cause mortality. Biomarkers of interest will largely focus on metabolism (lipids, amino acids) and inflammation (adipokines, cytokines and chemokines).

ETHICS AND DISSEMINATION

This study has been approved by the institutional review board at the Horizon Health Network. On completion of the study, the results shall be disseminated through conference presentations and publications in peer-reviewed journals. Additionally, the report shall also be diffused more broadly to the general public and the cardiovascular community.

TRIAL REGISTRATION NUMBER

NCT03248921.

Impact of body mass index on outcomes following mitral surgery: does an obesity paradox exist?

OBJECTIVES

This study was conducted to clarify the relationship between body mass index and mitral valve (MV) surgery and to determine whether an 'obesity paradox' exists in the context of surgery for degenerative MV disease.

METHODS

In this retrospective single-centre study, we analysed data from 715 patients who underwent mitral surgery for degenerative disease from 2000 to 2015. Patients were classified according to body mass index: underweight (<20 kg/m2), normal weight (20-24.99 kg/m2), overweight (25-29.99 kg/m2) and obese (≥30 kg/m2). Early and long-term results were investigated. Multivariable analysis was conducted to identify risk factors for long-term mortality.

RESULTS

Mean follow-up was 67 ± 44 months (range 0-190 months). There were no differences between groups regarding 30-day mortality (P = 0.35), stroke (P = 0.45), reoperation for bleeding (P = 0.9) and length of hospital stay (P = 0.31). Obese patients were at increased risk of acute kidney injury when compared with normal weight patients (17% vs 5%; P = 0.03) but not when compared with the other groups; this was confirmed within the subgroup with depressed ejection fraction (42% vs 10%, P = 0.02). No differences in long-term survival were found across groups for all patients (P = 0.62) and for patients with depressed ejection fraction (P = 0.6), with a trend towards worse survival in obese patients undergoing MV repair (P = 0.06). Survival in obese patients undergoing repair was significantly worse than that in obese patients undergoing replacement (P = 0.04).

CONCLUSIONS

An 'obesity paradox' was not demonstrated after surgery for degenerative MV disease. Obese patients are more prone to acute kidney injury and have worse late survival after MV repair.

GLP1 Receptor Agonist Liraglutide Is an Effective Therapeutic Option for Perioperative Glycemic Control in Type 2 Diabetes within Enhanced Recovery After Surgery (ERAS) Protocols

BACKGROUND

Enhanced Recovery After Surgery (ERAS) protocols are multimodal perioperative care pathways designed to achieve early recovery after surgical procedures by maintaining preoperative organ function and reducing profound stress responses following surgery [Wilmore and Kehlet: BMJ 2001; 322(7284): 473-6]. Glucagon-like peptide-1 receptor agonists (GLP-1RAgs), such as liraglutide, have recently been widely used as antidiabetic agents in patients with type 2 diabetes (T2D) because they maintain blood glucose at an ideal level throughout the day, including during postprandial periods, thereby improving hypoglycemia and body weight more than insulin therapies. Additionally, the administration of liraglutide may exert cardiovascular, renal, and cerebral protective effects in T2D patients. The use of GLP-1RAgs for perioperative glycemic control is sometimes considered to be controversial.

METHODS

The efficacy and safety of liraglutide therapy during perioperative glycemic control in elective surgery patients within ERAS protocols were compared with those of insulin therapy. Ninety adult T2D patients scheduled to undergo elective surgery within ERAS protocols were randomized and analyzed. Forty-nine subjects were prescribed liraglutide and 41 insulin therapy. Procedures comprised orthopedic, thoracic, urological, otolaryngological, hepatic resection, and gynecological breast surgeries.

RESULTS

Liraglutide was shown to be a more effective option than insulin therapy because (1) glycemic levels were more stable; (2) the number of patients requiring additional insulin according to the insulin sliding scale was significantly smaller (Fisher's exact test, p = 0.005); (3) the insulin dosage required on the day of surgery was significantly smaller (Fisher's exact, p = 0.004); (4) the additional insulin volume required was significantly less for patients throughout the perioperative period (Fisher's exact test, p = 0.001); and (5) while lean body mass remained the same, body fat measurements, particularly visceral fat, tended to decrease.

CONCLUSIONS

Based on the results of the present study and a recent large-scale clinical study showing cardiovascular and renal protective effects in T2D patients, we consider the administration of liraglutide within ERAS protocols for T2D patients to represent a more comprehensive suite of patient protection measures as a perioperative non-insulin agent, particularly in patients with limited exercise ability and those at risk of hypoglycemia.

Operative techniques for improving surgical exposure in basic cardiac surgery

Operative exposure is key to ensuring surgical efficiency and patient safety in cardiac surgery. As the population ages and the prevalence of obesity increases, cardiac surgeons will be challenged to consider obese patient physiology and body habitus, surgical exposure and sternotomy closure techniques, and postoperative medical management to ensure optimal outcomes. In this article, we describe techniques to improve operative exposure in both obese and non-obese patients undergoing basic cardiac surgery and highlight the roles of surgical team members to ensure patient safety and provide optimal anesthetic management. We describe pre-operative techniques regarding incision-site marking and alternative positioning techniques on the operating table to improve visualization and decrease risk of upper extremity injury. We summarized the roles of surgical team members regarding patient positioning, especially in those that are obese, and the challenges associated for anesthesia staff pre- and intraoperatively. Procedural techniques regarding sternotomy management and closure, cannulation, internal mammary harvest, and mitral valve exposure are discussed. Cardiac surgical teams must consider the risks associated with the obese patient population undergoing cardiac surgery procedures and employ techniques pre-, intra-, and postoperatively in a multidisciplinary fashion. Safe and efficacious techniques are paramount to optimal patient outcomes.