Survival in the NoLap Population

A prospective cohort study characterising patients declined emergency laparotomy: survival in the ‘NoLap’ population. E. C. Mcllveen et al. Anaesthesia. 2020 Jan;75(1):54-62. doi: 10.1111/anae.14839. Epub 2019 Sep 18.

Methods

Only adults over the age of 18 were enrolled, and were only eligible if they fulfilled NELA criteria for emergency laparotomy. There were several exclusion criteria:

  • Conditions related to the appendix or gallbladder
  • Herniae with no bowel resection
  • Trauma
  • Planned return to theatre
  • If indication for emergency surgery followed a different intervention eg IR drainage of an abscess

Data was collected primarily via the on call surgical registrar entering data into a secure database. Theatre logbooks and emergency CT lists were also reviewed to ensure coverage. 

Results

Surgery was indicated in 314 patients, 214 (68.2%) were operated on, 100 (31.8%) were not. All statistics shown are (median {IQR [range]}). Those not undergoing surgery were:

  • Older
  • More dependent
  • More likely to have co-morbidity
  • Higher ASA status
  • More likely to present with bowel ischaemia

In terms of baseline bloods, in the NoLap group baseline eGFR was lower than the operative group (56 {39-72[162}]). Pre-operative bloods were measured within four hours of the surgical review. They showed that eGFR was significantly lower in the NoLap group (43 {28–68 [164]}), compared to the operative group (82 {58–109 [199]}). Their creatinine was significantly higher (108 {73–173 [43–614]}) compared to the operative group 72 (61–99 [37–426]). Their lactate was also significantly higher (3.3 {1.5–5.5 [0.1–19.4]}), compared to 1.8 (1.0–3.5 [0.0–11.3]).

Background mortality was higher (1.2% {0.7–2.1 [0.0–9.8]}), and so was mortality as predicted by P-POSSUM (29% {14–74 [1–99]}) and a general mortality model (29 {15–44 [0–96]}). The predicted background median life expectancy in years was also lower (4 {2–6 [0–36]}).

Reasons for not operating showed that 80% were considered futile, due to poor fitness (74 patients) or advanced malignancy (6 patients). 4% were declined surgery and surprisingly in 16% no reason was documented.

Observed mortality rates showed some surprising results. There were 126/ 314 (40%) deaths during the study period – 52/214 (24%) deaths were after laparotomy, and 74/100 (74%) deaths in the group without surgery. However, 37% (37/100) were still alive after 30 days.

Most deaths occurred within one month of acute hospital admission. In all the cohort deaths, 90/126 (71%) were in the first month. 27/52 (52%) were deaths after laparotomy and 63/74 (85%) deaths without surgery.

Observed mortality rates in the month post-op [27/214 (13%)] were not statistically different from summed P-POSSUM model and general model rates [37/214 (17%) and 26/214 (12%), respectively, p = 0.22 and p = 1]. However, in the ‘NoLap’ group, one-month mortality rates were higher than expected (63/100, 63%) had they undergone surgery [summed P-POSSUM model and general model rates 40/100 (40%) and 30/100 (30%) deaths, p = 0.002 and p < 0.001) respectively].

After multivariate analysis, two factors affecting mortality were identified – background mortality (as predicted by the general model) and acute pre-op lactate

NELA standards of care were followed less well in the NoLap group as compared to the operative group. Noticeably, significantly less patients were risk assessed, less patients had the mortality risk documented and less had a consultant decision documented. However, in the NoLap group, the admission to surgical review and surgical review to decision time was significantly shorter. Despite a higher proportion of this cohort having a P-POSSUM >5% (89%), only 17% of these patients were admitted to critical care. 

Strengths

  • First UK study to attempt to characterise patients who are eligible for laparotomy but do not proceed to surgery
  • Prospective
  • All patients accounted for
  • Reliable data set

Weaknesses

  • Cohort study is a lower quality of study
  • Unlikely to be applicable to all hospitals
  • May have selection bias due to local practice
  • May have missed some cases e.g. where decision not to operate made by non-surgical team

Conclusion

This paper looked to characterise a patient population not often looked at – those eligible for emergency laparotomy but declined surgery. In terms of predicted mortality there were some unsurprising results, and on the whole the study confirmed what is already known. There were however some unexpected results. In this study, 37% of patients were not operated on, and a third of those survived past 30 days. Looking at the predicted vs observed mortality rates in the NoLap group, the data would suggest that more patients denied surgery would actually benefit from surgery. However, the decision to operate ultimately lies with the surgeon.

Summary by Dr Saq Naji

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