Sisse Olsen

Selecting pH cut-offs for the safe verification of nasogastric feeding tube placement: a decision analytical modelling approach

Objectives The existing British National Patient Safety Agency (NPSA) safety guideline recommends testing the pH of nasogastric (NG) tube aspirates. Feeding is considered safe if a pH of 5.5 or lower has been observed; otherwise chest X-rays are recommended. Our previous research found that at 5.5, the pH test lacks sensitivity towards oesophageal placements, a major risk identified by feeding experts. The aim of this research is to use a decision analytic modelling approach to systematically assess the safety of the pH test under cut-offs 1–9. Materials and methods We mapped out the care pathway according to the existing safety guideline where the pH test is used as a first-line test, followed by chest x-rays. Decision outcomes were scored on a 0–100 scale in terms of safety. Sensitivities and specificities of the pH test at each cut-off were extracted from our previous research. Aggregating outcome scores and probabilities resulted in weighted scores which enabled an analysis of the relative safety of the checking procedure under various pH cut-offs. Results The pH test was the safest under cut-off 5 when there was ≥30% of NG tube misplacements. Under cut-off 5, respiratory feeding was excluded; oesophageal feeding was kept to a minimum to balance the need of chest X-rays for patients with a pH higher than 5. Routine chest X-rays were less safe than the pH test while to feed all without safety checks was the most risky. Discussion The safety of the current checking procedure is sensitive to the choice of pH cut-offs, the impact of feeding delays, the accuracy of the pH in the oesophagus, as well as the extent of tube misplacements. Conclusions The pH test with 5 as the cut-off was the safest overall. It is important to understand the local clinical environment so that appropriate choice of pH cut-offs can be made to maximise safety and to minimise the use of chest X-rays. Trial registration number ISRCTN11170249; Pre-results.

Does axillary lymph node dissection impact survival in patients with breast cancer and isolated tumour cells or micrometastasis in sentinel node

We read with interest the article titled ‘Impact of completion axillary lymph node dissection in patients with breast cancer and isolated tumour cells or micrometastasis in sentinel nodes’ [1], published in your October 2016 issue. We agree with your findings that micrometastasis and isolated tumour cells (ITC) found in the sentinel node indicate planning a different treatment strategy of those patients. In your article, you seem to suggest that axillary lymph node dissection improves survival in patients with micrometastasis and not with ITC. We have recently conducted a similar study to yours on a similar cohort of patients [2]. We agree that there is a difference in outcome in patients who are found to have micrometastasis in the sentinel node. But there is not enough evidence to suggest that axillary lymph node dissection (ALND) affects the survival. Thex recent International Breast Cancer Study Group (IBCSG) 23-01 study didn’t show any statistical

Re: Infection prevention in implant surgery – A review of the surgical evidence, guidelines and a checklist

We read with interest the article “Infection prevention in implant surgery e A review of the surgical evidence, guidelines and a checklist” published in your May 2016 issue. We would like to share our unit experience and comment on some of the recommendations in your review related to it. We share many of your findings. Many of the factors you cited played an important role in our unit and many of your recommendations have already been introduced and improved our outcomes. Following an initial audit in 2014 which identified a loss rate of 17%, we reviewed each case of implant loss and a protocol was developed with the infection control and microbiology teams to minimise points of infection in the implant reconstruction pathway. This protocol was introduced in April 2015. In our initial audit, the most frequent source of infection was the patient’s own skin. However other unexpected organisms were also implicated: Group A Streptococcus, Escherichia coli, Serratia maracens, coliforms and Stenotrophomonas maltophilia. These unusual organisms and local organism resistance have influenced our choice of antibiotic. We routinely administer intravenous teicoplanin and gentamycin at induction and all patients receive oral doxycycline until drains are removed. You have recommended extending antibiotics treatment only in “high risk” cases. However we feel that the difference in risk of infection of 11.1% for a single dose versus 4.6% for extended antibiotics, which you quote, is enough to continue giving our patients an extended dose. Infection usually results in implant loss and the cost to the NHS is large and to the patient it is immeasurable. Practice may change when the results of iBRA are published.