Predictors and outcomes of withholding and withdrawal of life-sustaining treatments in intensive care units in Singapore: a multicentre observational study

BACKGROUND

Clinical practice guidelines on limitation of life-sustaining treatments (LST) in the intensive care unit (ICU), in the form of withholding or withdrawal of LST, state that there is no ethical difference between the two. Such statements are not uniformly accepted worldwide, and there are few studies on LST limitation in Asia. This study aimed to evaluate the predictors and outcomes of withholding and withdrawal of LST in Singapore, focusing on the similarities and differences between the two approaches.

METHODS

This was a multicentre observational study of patients admitted to 21 adult ICUs across 9 public hospitals in Singapore over an average of three months per year from 2014 to 2019. The primary outcome measures were withholding and withdrawal of LST (cardiopulmonary resuscitation, invasive mechanical ventilation, and vasopressors/inotropes). The secondary outcome measure was hospital mortality. Multivariable generalised mixed model analysis was used to identify independent predictors for withdrawal and withholding of LST and if LST limitation predicts hospital mortality.

RESULTS

There were 8907 patients and 9723 admissions. Of the former, 80.8% had no limitation of LST, 13.0% had LST withheld, and 6.2% had LST withdrawn. Common independent predictors for withholding and withdrawal were increasing age, absence of chronic kidney dialysis, greater dependence in activities of daily living, cardiopulmonary resuscitation before ICU admission, higher Acute Physiology and Chronic Health Evaluation (APACHE) II score, and higher level of care in the first 24 h of ICU admission. Additional predictors for withholding included being of Chinese race, the religions of Hinduism and Islam, malignancy, and chronic liver failure. The additional predictor for withdrawal was lower hospital paying class (with greater government subsidy for hospital bills). Hospital mortality in patients without LST limitation, with LST withholding, and with LST withdrawal was 10.6%, 82.1%, and 91.8%, respectively (p < 0.001). Withholding (odds ratio 13.822, 95% confidence interval 9.987-19.132) and withdrawal (odds ratio 38.319, 95% confidence interval 24.351-60.298) were both found to be independent predictors of hospital mortality on multivariable analysis.

CONCLUSIONS

Differences in the independent predictors of withholding and withdrawal of LST exist. Even after accounting for baseline characteristics, both withholding and withdrawal of LST independently predict hospital mortality. Later mortality in patients who had LST withdrawn compared to withholding suggests that the decision to withdraw may be at the point when medical futility is recognised.

Perioperative risk factors in obese patients for bariatric surgery: a Singapore experience

INTRODUCTION

Morbid obesity and obstructive sleep apnoea (OSA) are increasingly encountered in anaesthetic practice today. Difficult intubation may be seen more frequently in our practice. This high-risk group may also be more prone to complications in the postoperative period.

METHODS

We reviewed a consecutive series of patients who had undergone laparoscopic gastric banding at our institution from 2001 to 2006. The incidence of difficult intubation, early postoperative complications and its attendant risk factors were studied.

RESULTS

Severe OSA and neck circumference greater than 44 cm were factors associated with difficult intubation in morbidly obese patients who presented for bariatric surgery. Asthma and increasing age may be associated risk factors for adverse events in the postoperative period.

CONCLUSION

It is important to anticipate and prepare for a difficult intubation scenario in patients with severe OSA and a larger neck circumference. Close monitoring is recommended for patients with respiratory comorbidities and advanced age.

Comparison between use of neuromuscular blocking agent and placebo with the intubating laryngeal mask airway

INTRODUCTION

The intubating laryngeal mask airway (ILMA) is a specially-designed airway device that can be used for endotracheal intubation without direct laryngoscopy. The advantage of this device is that it allows blind endotracheal intubation with a predictably high success rate. The use of neuromuscular blocking agents in facilitating the use of the ILMA has been investigated in the Western population with a quoted successful intubation rate of 88-96 percent. This randomised, double-blind study aimed to see if the use of neuromuscular blocking agent is necessary for successful intubations.

METHODS

A total of 150 patients, rated categories 1 and 2 on the American Society of Anesthesiology Physical Status Classification System, were induced with propofol 2.5 mg/kg and fentanyl 2 microg/kg. After insertion of the ILMA, the patients received either saline or 0.6 mg/kg of rocuronium. After 90 seconds, tracheal intubation was attempted using the specially-designed silicon endotracheal tube. In addition to the success rate of intubation, the incidence of complications was also recorded.

RESULTS

The success rate for tracheal intubation within three attempts was 93.3 percent for the saline group and 92.0 percent for the rocuronium group; this was statistically insignificant. The time to securing the airway was 11.5 seconds for the saline group, compared to 10.0 seconds in the rocuronium group, but this was statistically insignificant. The incidence of coughing during insertion of the endotracheal tube was 42.7 percent in the saline group as compared to 1.3 percent in the rocuronium group (p-value is less than 0.001). 12 percent of the patients in the saline group moved during intubation, while none was reported to move in the rocuronium group (p-value is 0.003). These results compared favourably with rates quoted in studies conducted on Western populations.

CONCLUSION

The intubating laryngeal mask airway-assisted intubation yields a high success rate, which was similar between the paralysed and non-paralysed patients, with no statistical significance. However, the non-paralysed patients were prone to coughing and movements during intubation, requiring supplemental propofol.