Pre-procedure ultrasound as a tool for teaching landmark method for central venous cannulation

Abstract

Our work was deliberately focused on the selected obese population. As suggested by Alex Czech, in order to assess the effect of obesity on the incidence of difficult intubation in both the operating theatre (OT) and the intensive care unit (ICU), we have calculated the incidence of difficult intubation in the nonobese population during the study period. The incidence of difficult intubation in non-obese patients was of 99/1118 (9%) in the ICU vs 419/8932 (5%) in the OT (odds ratio=1.9, 95% confidence interval 1.5-2.4), whereas the incidence of difficult intubation in obese patients was of 46/282 (16%) in the ICU vs 172/2103 (8%) in the OT (odds ratio=1.9, 95% confidence interval 1.9-2.6). Therefore, the risk of difficult intubation was almost two-fold higher in the ICU than in the OT in both obese and non-obese populations. Besides, we do realize that the patients intubated in the ICU and the OT have very different characteristics and that the circumstances in which intubation is undertaken are very different.As accurately stated by Dr Glossop and Dr Esquinas, hypoxaemia and cardiovascular collapse were the two most common severe complications seen after intubation in obese ICU patients. However, hypoxaemia and cardiovascular collapse were considered as complications only if they were not present before intubation. Therefore, it does not seem likely that it is 'merely a manifestation of the worsening pathophysiology already frequently present'. Furthermore, rapid sequence induction was naturally much more used in ICU patients than in OT patients, which is not surprising because rapid sequence induction is the standard of care in ICU patients particularly at risk of full stomach, compared with patients in the OT.The main message of our study is not that patients are comparable between the ICU and the OT, because they clearly differ. The ICU patients are much more severe than the OT patients, with more rapid sequence induction, and that is why stronger efforts should be made in airway management in the ICU. The patients intubated in the ICU are, for many reasons, at higher risk of difficult intubation and airway complications. We were surprised by the low rate of use of difficult intubation devices in the ICU in this high-risk context. We think that the priority should be to prevent difficult intubation and its complications rather than proceed to rescue therapeutics after the occurrence of complications in extreme emergency. We think that, when integrated in an airway management algorithm, 2 the use of airway adjuncts is not an 'unaffordable luxury' whilst attempting to stabilize the patient.We agree with Dr Glossop, Dr Esquinas, and Dr Nair when they accurately noticed that most of the intubations were performed 'out of hours' and in extreme emergency, often by non-expert operators. This is another argument in favour of introducing the expertise acquired in the OT to the ICU, to reduce the lifethreatening complications associated with intubation.One of the limits of the study is the bias induced by the different...