Term 3 week 9 (w/c 25/06/2012)
Welcome to week 9 of this term.
This week we are back to the general surgery theatre.
To begin with, list the concerns and considerations which may be relevant when anaesthetising a patient for a laparoscopic cholecystectomy.
You have been seconded to the anaesthesia department of a large quaternary centre in a developing country. You have been assigned to the general surgery list on Monday morning.
On Friday afternoon, the surgical house officer phones you to tell you that she is somewhat concerned about one of the patients on the list. The patient is a 17 year old female, and is booked for a laparoscopic cholecystectomy.
She tells you that she is worried because she thinks that the patient “looks cyanotic”
A consult has been requested.
What are your initial thoughts as you head up to the ward?
Thanks for all the input to date.
On arrival in the ward, you find a 17 y old female who is indeed centrally cyanotic, 45kg and 1,5m. Room air sats are 85%.
There is a significant language barrier but you elicit that she has had a number of cardiac procedures.
On examination, she is able to lie flat with minimal discomfort. There is significant digital clubbing. Her JVP is elevated to the angle of the jaw, she has trace peripheral oedema and a small amount of ascites along with right upper quadrant tenderness. Examination of the chest reveals a number of scars including a sternotomy scar. There is a soft pansystolic murmur heard over the entire precordium. She is not in respiratory distress, and there is no evidence of systemic sepsis.
The file is spectacularly unhelpful. No past records are available for perusal.
You eventually track down the paediatric cardiac surgeon who remembers the patient. The cardiac history is that she was born with a hypoplastic left heart. She has had a single ventricle palliation as follows – central shunt as a neonate, bidirectional Glenn shunt at age 4, whereafter she was lost to follow up until age 13 at which point she had a completion Fontan procedure.
She has had intermittent follow up since then but has not been seen for 18months.
What are your thoughts now about the cholecystectomy??
Some really interesting input yesterday. Thank you for all your contributions. For the moment, and to “simplify” matters somewhat, let’s concentrate on how we would anaesthetise a grown up patient presenting with a Fontan circulation for a laparoscopic cholecystectomy.
The cyanosis in this case is most likely an indication that the fenestration created between the central venous circulation and the right atrium is functioning to relieve an increase in pulmonary vascular resistance. For today and to finish off our discussion, let’s ignore the cyanosis.
How would you anaesthetise this patient for a lap cholecystectomy? Would you allow a laparoscopic procedure? What are the effects on the circulation of the issues around laparoscopic surgery in a Fontan circulation?
Thank you all for the input this week. This is a hyper specialised clinical problem and one which few of us will have to face. Typically (in a first world environment) these patients will be well known and managed at centres of excellence and expertise in GUCH (Grown up Congenital Heart diseases).
It is probably not really necessary to expound further on the issues surrounding laparoscopic surgery in the healthy non cardiac individual. The changes in preload, respiratory compliance and intra-abdominal perfusion are well recognised in these commonly performed procedures.
The patient with a Fontan palliation for HLHS presents unique challenges in the perioperative period when non-cardiac surgery is undertaken. Essentially, the Fontan procedure entails direct connection of the IVC to the pulmonary artery, where it joins the SVC (which is typically connected to the PA as part of a bidirectional Glenn shunt at an earlier age).
The implication of this is that there is no cardiac activity driving pulmonary perfusion. Pulmonary perfusion depends essentially on the gradient between mean venous systemic filling pressure and pulmonary pressure. The Fontan operation also generally creates a fenestration from the IVC into the common atrium which acts as a pop-off valve to allow for continued circulation in the event of an increase in pulmonary vascular resistance. This may go some way to explain why patients with a Fontan ciculation may become cyanotic under some circumstances. Cyanosis in a patient with a completed Fontan palliation should provoke intensive investigation as to the downstream resistance in the lungs.
Some of the complications related to the Fontan circulation relate to the increased central venous pressures – ascites, hepatic congestion, gut oedema and associated protein losing enteropathy are all relatively common. These patients may well present with gallstones requiring cholecystectomy.
The combination of CO2 insufflation, steep head up position and positive pressure ventilation may prove to be disastrous in a Fontan circulation. Pulmonary perfusion drops with resultant hypoxaemia, an increase in pulmonary vascular resistance and recruitment of the fenestration leading to significant right to left shunt.
Correct management of intravascular volume is also critical, with these patients requiring significant fluid loading due to their preload dependance.
Choice of technique would depend on local expertise, but it would seem prudent to do an open cholecystectomy, with experienced surgical and anaesthesia consultants. Input from Paediatric cardiologists skilled in the interpretation of congenital echocardiograms is critical. These are not cases for district and peripheral hospitals.
The interested reader is referred to the European Guidelines for GUCH at http://www.escardio.org/guidelines-surveys/esc-guidelines/GuidelinesDocuments/guidelines-GUCH-FT.pdf (Thanks @cringlem)
Additionally, an excellent review on the perioperative implications of Single Ventricle physiology can be found in the following article
Walker SG, Stuth EA: Single Ventricle Physiology : Perioperative implications; Seminars in Pediatric Surgery 2004: 13(3) pp 188-202