KB-2023-001134 - [2025] EWHC 2121 (KB)

Preliminary Issue 2: how much time would have been ‘saved’ but for the established breach(es) of duty?

It is common ground between the parties that had the femoral vessels been exposed and prepared in advance of the sternotomy then full cardiopulmonary bypass would have been achieved more quickly following the injury to the aorta, but there is disagreement between the experts as to how much time would have been saved by adopting this course. The Claimant’s pleaded case is that “had the artery been exposed and slings placed in advance, a process which takes some 5-10 minutes, some 5 to 10 minutes would have been saved from the overall period of hypoxia in the event of emergency”.

In addition, there is an issue between the parties as to whether the dissection of the femoral artery during the attempt at cannulation was caused or contributed to by the failure to expose and prepare the vessels in advance of the sternotomy. This was an issue which was raised by the Claimant’s amendments in July 2024. The amended pleading on causation alleges that “the cause of the dissection was iatrogenic, occurring as a result of the panic of the emergency; and would not have occurred had preparations been made in advance for bypass and cannulation”.

As explained at [32] above, following the injury to the aorta Mr Nassar attempted to stem the haemorrhage before moving to expose the left femoral vessels for cannulation to enable cardiopulmonary bypass to be established. At some point, Mr De Rita joined in theatre. There is no clinical note identifying the time when Mr De Rita joined in theatre.

Mr Nassar’s evidence was that his best estimate is that Mr De Rita would have been present in theatre within ten minutes of the injury occurring. Once Mr De Rita was in theatre, Mr Nassar moved to focus on attempts to stem the haemorrhaging of the aorta and so was not in a position to give direct evidence as to the circumstances in which the groin vessel dissected when Mr De Rita, an experienced consultant surgeon, attempted cannulation.

No witness statement was served by the Defendant from Mr De Rita notwithstanding that the amendments to the Particulars of Claim relating to the dissection of the vessel had been made in July 2024 and factual statements were not served until January 2025. Accordingly, there is no evidence from Mr De Rita as to the time when he joined in theatre, nor the circumstances in which the femoral artery dissected when he attempted cannulation. There is no evidence from him, therefore, as to whether the dissection was a random occurrence as claimed by the Defendant, or whether it was caused or contributed to be the “panic” of the emergency as claimed on behalf of the Claimant. Mr Elgot also emphasised that, as a result, we had no evidence from Mr De Rita as to why the dissected artery needed to be repaired with a bovine pericardial patch, which, it was suggested by Mr Yap, might indicate damage from use of a cannula which was too large.

Similarly, there was no witness statement served from Professor Clark who also joined theatre to assist in the emergency. It is not clear to me from the evidence precisely what aspects of the surgery Professor Clark assisted with. Mr Mohamed’s statement did not deal with the surgery itself, albeit that he was in theatre for at least part of the surgery; again, it is not clear to me from the evidence precisely what roles Mr Mohamed assumed at different points in the surgery.

There is limited information available on intraoperative timings from the medical records. In his first statement Mr Nassar had stated that heparin, an anti-coagulant, was administered once the cannula was sited and that once the activated clotting time (“ACT”) was available it was safe for the Claimant to go on bypass. However, in his second statement Mr Nassar corrected this statement and explained that in an emergency situation of this nature one would not wait for the ACT measurement before placing the patient on bypass. Mr Roberts also accepted that it is likely that the heparin was administered before the cannula was sited. It is unfortunate that Mr Nassar’s evidence was erroneous on this issue.

The aortic injury is recorded as having occurred at 12:25. The perfusion report records heparin as having been administered at 12:32, some 7 minutes later. There is also a note in the perfusion report recording “crashed onto sucker bypass at 12:45”, some 13 minutes later, which would have been shortly after central cannulation (of the aorta) was achieved by Mr Nassar. Thus, there was a period of approximately 20 minutes from the aortic injury until sucker bypass. Full bypass was recorded as being achieved at 12.49, some 24 minutes later.

Mr Yap’s written evidence was that “at least 10 mins and probably more” would have been saved had the vessels been exposed in advance of the sternotomy, leaving aside the issue of the dissection of the femoral artery. In cross-examination he said that just to expose and cannulate might take 5 to 10 minutes in normal circumstances, but in the stressful situation of a catastrophic haemorrhage and depending on the quality and position of the vessel, then “10 minutes or more” is a reasonable estimate.

It is not alleged that there was any negligence on the part of Mr De Rita in relation to the dissection of the left femoral artery during attempted cannulation. The experts agreed that “vessel dissection is a rare event either during elective cannulation of vessels or during emergencies. The experts agree that vessel dissection cannot be predicted in advance and may occur in a non-negligent event.” They also agreed that “surgical performance can be impaired to some extent in an emergency situation, but that surgeons are trained to act calmly in these situations.”

Mr Yap referred to a paper entitled “Complications Associated with Femoral Cannulation During Minimally Invasive Cardiac Surgery” Lamelas et al, Annals of Thoracic Surgery 2017; 103:1927 in support of his evidence that it is very rare to cause a dissection of a femoral artery when using an appropriately sized cannula by direct introduction; the data from the paper indicated 2 such injuries in the 2,645 cannulations considered, or 0.075% of those cases. He questioned whether the correct sized cannula was used and whether the use of a bovine patch to repair the artery might indicate that damage had been caused by the use of too large a cannula.

Mr Yap also makes the point that the detrimental effect of stress on technical and non-technical (decision making, situation awareness) skill during surgical procedures are well recognised. In support of this proposition he refers to the paper The effects of stress on surgical performance: a systematic review Adam Tan et al, Surgical Endoscopy (2025) 39: 77-98.

Whilst accepting that dissection can occur in any event, Mr Yap’s opinion was that had the relevant groin vessels been exposed and prepared prior to commencing the sternotomy then it would have been “possible to examine and assess the quality and calibre of the vessel directly” and would have provided greater certainty as to the choice of the cannula size. He also considers that “exposed vessels would generally be easier to cannulate.” Mr Yap considers that dissection of a vessel of this nature is rare and probably “would not have happened if the femoral artery was exposed and ready”. In the joint statement he says “the failure to expose the vessel before sternotomy materially contributed to the vessel dissection when it was canulated. A prepared vessel is always going to be easier to handle. Haemostasis would have been done during preparation.” In other words, the inevitable bleeding associated with newly exposed vessels would have been controlled during the course of preparing the vessels in advance, making them easier to handle when subsequently attempting cannulation.

Mr Roberts’ position was that “a few minutes extra were taken to open the groin which is quick and easy to do” and that “3-5 mins might have been saved” and, separately “less than 5 minutes” would have been saved by exposing the vessels in advance. He also takes the view that the dissection of the femoral artery was entirely independent of the decision not to expose and prepare the vessel in advance; it was, in his opinion, “a random, unforeseen event that on the balance of probability was not due to panic”. He says that the main delay was the (non-negligent) time taken to obtain central cannulation following the (non-negligent) dissection of the femoral artery on attempted cannulation, which, as noted above, he considered would have occurred even if the vessels had been exposed in advance.

There is limited evidence available from the clinical records which assists on the issue of how long it initially took to attempt cannulation. If Mr Nassar is correct to suggest that Mr De Rita would have taken ten minutes to respond to the emergency bleep and scrub in and, further, that it was Mr De Rita who attempted to cannulate the femoral artery, then it seems that at least ten minutes passed between the aortic injury and any attempt at cannulation. Mr Nassar’s time was occupied during this ten-minute period by an initial attempt to stem the haemorrhaging and then by having to expose and begin to prepare the femoral vessels. There is no reliable evidence as to how much time, if any, Mr De Rita took in preparing the femoral vessels before attempting cannulation.

Whilst I have no direct evidence on the point, I think it is likely that Mr Nassar would have appreciated relatively swiftly (say, within one or two minutes) that his efforts to stem the catastrophic haemorrhaging were unlikely to be successful and would have moved rapidly to exposing the femoral vessels. If this is correct, then it seems that the majority of this ten-minute period, perhaps something like 8 minutes, would have been spent on exposing and preparing the femoral vessels.

Taking Mr Yap’s evidence in its totality, his position was that ten minutes or more is a reasonable assessment of the time that would have been saved had the femoral vessels been exposed and prepared in advance of the sternotomy. I also see the force of Mr Yap’s evidence that attempting to expose, prepare and cannulate a femoral vessel in the context of a catastrophic haemorrhage may be more difficult and take longer than would usually be the case precisely because blood pressure will be lower as a result of the haemorrhage, rendering it harder accurately to locate the relevant blood vessels.

There is then a separate, but linked, issue as to whether the femoral artery would have dissected in any event had the femoral vessels been exposed and prepared in advance of the sternotomy. The only person who could possibly offer direct evidence as to the circumstances in which, and the reasons why, the femoral artery dissected is Mr De Rita, but the Defendant served no evidence from Mr De Rita.

I accept Mr Yap’s evidence on the following points: (a) if the relevant vessels been exposed at the outset, in a non-emergency setting, then an assessment could have been made as to the quality and calibre of the vessel directly (and at a time when blood pressure in the vessels was normal); (b) such an assessment would have provided greater certainty as to the choice of the cannula size; (c) that “a prepared vessel is always going to be easier to handle. Haemostasis would have been done during preparation” and that “[pre] exposed vessels would generally be easier to cannulate”; and (d) the detrimental effect of stress on technical skills during surgical procedures are well recognised.

Whilst I accept the evidence of the experts that dissection of an artery can occur in any event, I am satisfied that had the relevant vessels been exposed in advance then it would have been substantially easier to cannulate the femoral artery for the four reasons identified by Mr Yap and set out above and that, for these reasons, the risk of accidental dissection of the artery would have been reduced. I accept Mr Yap’s expert opinion evidence that, in such circumstances, it is more likely than not that cannulation would have been achieved without dissecting the femoral artery had the relevant vessels been exposed and prepared in advance.

Mr Elgot invited me in closing submissions to draw an adverse inference from the fact that the Defendant had failed to serve a witness statement from Mr De Rita explaining the circumstances in which the femoral artery dissected. In support of this submission, Mr Elgot relied on the following principles set out by Brooke LJ and distilled from his review of the relevant caselaw in Wisniewski v Central Manchester Health Authority, Court of Appeal, [1998] P.I.Q.R. P324, page 340:

“(1)

In certain circumstances a court may be entitled to draw adverse inferences from the absence or silence of a witness who might be expected to have material evidence to give on an issue in an action.

(2)

If a court is willing to draw such inferences, they may go to strengthen the evidence adduced on that issue by the other party or to weaken the evidence, if any, adduced by the party who might reasonably have been expected to call the witness.

(3)

There must, however, have been some evidence, however weak, adduced by the former on the matter in question before the court is entitled to draw the desired inference: in other words, there must be a case to answer on that issue.

(4)

If the reason for the witness’s absence or silence satisfies the court, then no such adverse inference may be drawn. If, on the other hand, there is some credible explanation given, even if it is not wholly satisfactory, the potentially detrimental effect of his/her absence or silence may be reduced or nullified”.

To similar effect, in Prest v Petrodel Resources Limited and others[2013] UKSC 34 Lord Sumption adopted (with a certain modification in the context of ancillary financial relief claims) the following summary provided by Lord Lowry with the support of the rest of the committee in R v Inland Revenue Commissioners, Ex p TC Coombs & Co [1991] 2 AC 283, at 300:

“In our legal system generally, the silence of one party in face of the other party's evidence may convert that evidence into proof in relation to matters which are, or are likely to be, within the knowledge of the silent party and about which that party could be expected to give evidence. Thus, depending on the circumstances, a prima facie case may become a strong or even an overwhelming case. But, if the silent party's failure to give evidence (or to give the necessary evidence) can be credibly explained, even if not entirely justified, the effect of his silence in favour of the other party may be either reduced or nullified.”

Given (a) that this trial of preliminary issues was focused on the issues of alleged breaches of duty and the time that may have been saved but for any such breaches; and (b) the pleading of a positive case that the femoral artery dissected as a result of “panic of the emergency” and would not have dissected had the relevant vessels been exposed and prepared in advance; and (c) that dissection of a femoral artery on cannulation is not a common event; and (d) that it is possible that the dissection of the femoral artery may have caused delay in establishing cardiopulmonary bypass; and (e) that Mr Nassar was not able to give evidence as to the circumstances in which the femoral artery dissected, then I would have expected efforts to be made by the Defendant to obtain a witness statement from Mr De Rita explaining the circumstances in which the femoral artery dissected when he attempted cannulation.

No proper explanation has been advanced by the Defendant to explain the absence of a witness statement from Mr De Rita. Mr Nassar’s understanding that Mr De Rita is no longer employed by the Defendant trust and may now be resident in Italy does not constitute an explanation of the failure to serve a witness statement from Mr De Rita. Consideration could, of course, have been given to serving a statement from Mr De Rita together with a Civil Evidence Act Notice if it was anticipated that there would be difficulty in calling Mr De Rita to give oral evidence. I also note that the CMC directions order sealed on 20 June 2024 directed, in relation to witness statements, that “for the avoidance of doubt statements of all concerned with the relevant treatment and care of the Claimant must be included”.

In the circumstances, even if I had not already reached the conclusions set out at [156] above, then it would, in my judgment, have been appropriate to draw an inference from the failure of the Defendant to serve a witness statement from Mr De Rita. The appropriate adverse inference to draw, in my judgment, would be that Mr De Rita’s evidence would have supported the Claimant’s case that the failure to expose the relevant groin vessels in advance of the sternotomy caused or contributed to the difficulties which led to the dissection of the femoral artery under the pressures of the emergency with which Mr De Rita was faced when called into theatre to assist Mr Nassar. Such an inference would have been consistent with Mr Yap’s opinion evidence on this issue, as set out at [155] above.

Mr Yap did not specifically address the additional time which he says would have been saved had the femoral artery not dissected. However, in the joint statement he expressed the view, in answer to question 18, that the dissection would probably not have happened had the femoral artery been exposed and prepared in advance and, in response to question 19, he gave his overall opinion that “at least 10 minutes and probably more” would have been saved had the femoral vessels been exposed and prepared in advance.

As noted at paragraph [144] above, the perfusion report records the aortic injury occurring at 12:25, sucker bypass at 12:45, being 20 minutes after the injury and which would have been shortly after cannulation was established via the aorta, and full bypass at 12.49, some 24 minutes after the injury. On the balance of probabilities, I find that 13 minutes (being 65% of the 20 minute period taken to achieve sucker by-pass and 54% of the 24 minute period to full bypass) would have been saved had the femoral vessels been exposed and prepared in advance of the sternotomy. This is in accordance with Mr Yap’s evidence, dealing with matters in the round, that “at least 10 minutes and probably more” would have been saved had the femoral vessels been exposed and prepared in advance. In other words, I accept the evidence that it was “probably more” than 10 minutes and, doing the best I can on the limited evidence, I have assessed the “probably more” element as an additional 3 minutes when taking into account both the issue of the time saved by exposing and preparing the femoral vessels and the additional time taken in relation to the dissection of the artery.

Insofar as it may be helpful to break this assessment down further, I attribute approximately 6-8 minutes to the time taken to expose and prepare the femoral vessels (taking into account both Mr Roberts’ assessment of 3-5 minutes and Mr Yap’s assessment of 5-10 minutes) and the remaining 5-7 minutes to the time which would have been saved had the femoral artery not dissected, which dissection I have found, on the balance of probabilities, to have been caused by the lack of advance exposure and preparation of the femoral vessels. I emphasise that these are not, and cannot be, scientifically valid calculations; they are approximate estimates, on the balance of probabilities, based on an assessment of the limited contemporaneous evidence and the expert opinion evidence before me. As noted above, had a witness statement been served from Mr De Rita, then he may have been able to provide additional clarity in respect of the timings.

This second preliminary issue was limited to the question as to the period of time that would have been saved in the absence of the breach of duty. Accordingly, no evidence was adduced on issues of causation in terms of the neurological consequences, if any, of this period of delay and so, unless capable of agreement, such matters will fall to be determined at a future date.