Amongst traditionally-available frameworks within which end-of-life decisions in Intensive Care Units (ICU) are situated, we favour Ordinary versus Extra-ordinary care distinctions as the most helpful. Predicated on this framework, we revisit the concepts of personhood and autonomy. We argue that a full account of personhood locates its foundation in relationships with others, rather than merely in "rationality". A full account of autonomy also recognises relationships with others, as well as the actual reality of the patient's situation-in-the-world. The fact that, when critically ill, the patient may no longer be able to take an active role in decision-making does not bring about the end of their personhood, or of their autonomy. Because the patient's autonomy is intimately linked to their relationships with others, once critical illness supervenes, respect for their autonomy devolves to those others with whom the patient is in relationship. In practical application, this means that there must be a dialogue, as the end-of-life of the critically-ill patient in ICU comes into view. Such dialogue should be grounded on this understanding in order to conform best to moral philosophical principles. Ideally the dialogue will involve all those with whom the patient is in relationship and, practical difficulties within an ICU notwithstanding, will aim to be inclusive, non-coercive and reflective as it seeks to maximise the good of the patient in their unique context.