Upper GI surgery

Question 1

What’s the indication for Ivor Lewis oesophagectomy? Most common reasons?

Answer 1

Mid to distal oesophageal pathology, usually oesophageal squamous or adenocarcinoma. Other causes= high-grade dysplasia in Barrett’s w proximal extension >35cm, failed myotomy for achalasia w sigmoid oesophagus or other oesophageal disorders requiring removal of most of the oesophagus.

Question 2

What are the stages of an Ivor Lewis oesophagectomy?

Answer 2

1. Abdominal phase- Pt supine. Laparotomy- upper midline incision (T6-10) or “rooftop” (T8-9 bilaterally- advantageous as closer to the thoracotomy incision, easier for Tx epidural coverage).
   To mobilise the stomach & distal eosophagus & enlarge the hiatus, allowing the stomach & oesophagus to be mobilised into the chest for creation of the gastric conduit.
   First explore abdomen- if find liver mets or un-resectable retroperitoneal nodes, abandon resection & consider alternative palliation for dysphagia.
   If tumor resectable, mobilise the stomach by separating off enough omentum to allow the stomach to be mobilised into the chest. Aim to preserve the gastroepiploic artery. Ideally preserve some of the greater omentum for later to cover the anastamosis. A gastric tube may be formed by stapling the stomach & a pyloroplasty or pyloromyotomy may also occur.
   At this point most patients will have a feeding jejunostomy inserted.
2. Thoracic phase- pt in L) lateral decubitus. DLT inserted. posterolateral R) thoracotomy performed, sparing the serratus muscle, entering through the 4th or 5th interspace. Inspect the lung for abnormalities, deflate it & retract it anteriorly, exposing oesophagus & adjacent tissues for dissection en bloc. All of the necessary thoracic dissection is performed & part of stomach is pulled into the chest & divided. It’s important that the surgeons get the right amount of stomach to minimise issues with post-op gastric emptying.
   The anastomosis between the oesophagus & stomach is then created. NG tube inserted under direct vision before closure of the anastomosis. NGT secured w sutures @ the end of the case.

Question 3

How common is oesophageal cancer & what proportion of pts have metastases on initial presentation?

Answer 3

8th most common malignancy worldwide & incidence is rapidly increasing.
20-30% have metastases @ initial presentation.

Question 4

What is the most common type of oesophageal Ca in the western vs developing world & risk factors that may explain this?

Answer 4

Adenocarcinoma 80% vs squamous cell carcinoma 20% in western society, squamous cell carcinoma more common in developing world.
Lifestyle: Smoking is a risk factor for both, for squamous ETOH + poor oral hygiene also.
Race: Caucasian for adeno, sub-saharan African & far-east asian for squamous.
Low dietary fruit & veg for adeno, salted veg/preserved fish for squamous.
Both more common in males.

Question 5

Which pts with oesophageal carcinoma will also have had neo-adjuvant chemotherapy? What are some adverse effects of cisplatin & 5-fluroruracil? What are some anaesthetic considerations where the pt has had neoadjuvant chemo?

Answer 5

Those with T3 (tumour invading oesophageal adventitia but not distant structures) or N1 (regional LN mets) disease.
Hepatotoxic & cardiotoxic. Cisplatin also nephrotoxic.
Consider the organ toxicities of the pts chemo regimen.
Consider that while a washout period before surgery may have allowed normalisation of hematopoiesis, the pt may still have leukopenia & incr susceptibility to infection, anaemia & risk for transfusion requirement & thrombocytopenia & increased bleeding risk.
If the pt has had complications from chemo need multi-D discussion re: delaying surgery to allow adequate recovery or early cessation chemo to optimise pt fitness for surgery.

Question 6

What factors, from CPET, are correlated with increased perioperative risk?

Answer 6

Inability to deliver 800mL/min/m2 oxygen & a lower anaerobic threshold. Decline in peak O2 delivery & anaerobic threshold occur after chemo but these values normally improve w time before surgery.

Question 7

What are some preoperative anaesthetic considerations prior to oesophagectomy?

Answer 7

Cognitive status & consent issues, including discussion of pt-specific higher risk elements, CVC, art line, regional anaesthetic.
B: Poor pulmonary function is a risk factor for periop m&m. Smoking cessation vital.
COPD common in this population due to ass’n w smoking & adeno + Sq cell carcinoma
Cancer:
consider if been on chemo (organ toxicity, infection risk, bleeding risk, anaemia)
metastases? (in 20-30% of pts @ initial presentation)
metabolic effects? (cachexia)
mass effects? (dysphagia, ?RLN)
D: frailty common
H: preop Fe-deficiency anaemia management.
Consideration of chemo effects on bleeding risk
Hepatic disease common in this cohort as Sq cc associated with ETOH excess.
G: Nutrition vital- dietician should be involved pre-op- pts may be obese but still malnourished, may have a reflux-associated carcinoma or have dysphagia & cancer cachexia (this & obesity both pressure injury risk)
High risk pulmonary aspiration of gastric contents

Question 8

For which pts is nutritional supplementation or tube feeding via NG or jejunostomy (which may be inserted @ the time of staging laparoscopy) indicated?

Answer 8

If pts fail to take 75% of their goal calories supplementation is indicated.
If pts fail to take 50% or more of their goal calories, tube feeding is indicated.

Question 9

Has rehabilitation been specifically evaluated for oesophagectomy?

Answer 9

Not yet

Question 10

What are some intra- & postop considerations for oesophagectomy?

Answer 10

A:
Intubation- often w RSI as pts w oesophageal pathology have high risk pulmonary aspiration eg. due to oesophageal mass, stricture or achalasia. DLT most often used for the thoracoscopic/open thoracic component- occasional bronchial blocker could be used. Sometimes prone thoracoscopy is performed with partial deflation of both lungs so liaise closely w surgeon re: optimal technique.
Care re: preventing, detecting & correcting any DLT migration.
Aim for extubation in theatre if parameters allow.

B: Often (except for trans-hiatal oesophagectomy) OLV.
Require airway plans A, B & C with alternatives including an assortment of ETTs & bronchial blockers. Sometimes the surgeon insufflates CO2 into the intrapleural space to aid surgical access for thoracoscopy & the incr PaCO2 can be difficult to compensate for during OLV.

C:
-Haemorrhage risk- 2x large-bore IVC, G&H
-arrhythmias & ventricular compression causing hypotension may occur during dissection around the mediastinum, commonly during transhiatal & uncommonly with other approaches.
-The anastomosis is vulnerable to ischaemia as it’s formed @ extreme of the foregut’s blood supply so haemodynamic & fluid management important to ensure perfusion maintained.

D:
Early postop mobilisation.
Drugs: be cogniscent of obesity or cachexia & the impacts on drug dosing.

F:
Fluid management.
Excess risks pulm oedema & venous congestion of the anastamosis while inadequate risks vasoconstriction which risks AKI, myocardial strain & ischemia of the anastamosis.
Overall, avoid large vols intraop (no >4L) but monitor UO to ensure fluid input not inadequate.

G:
Risk pulm aspiration
Consider 30mL Na citrate 10 mins prior to RSI (unless significant oesophageal obstruction or motility disorder)
P: pain management- multimodal incl regional. Important for intra-op surg stress AND postop resp function, mobilisation & prevention of complications. CHRONIC PAIN also significant after thoracotomy, this can be reduced by good early postop analgesia.
Tx epidural has been shown to reduce incidence of chronic post-thoracotomy pain & reduces time ventilated & ICU stay & postop opioid requirement. Considered gold standard- use for the first 3-5 days postop even after minimally invasive oesophagectomy.
Tx paravertebral has been shown in meta-analysis to have equal efficacy, lower failure rate & fewer side-effects & pulmonary complications cf Tx epidural for thoracotomy BUT this may not be applicable to oesophagectomy as they don’t cover the abdo wound.
Pre-emptive ketamine (after induction but b4 surg incision- placebo-controlled, double blinded prospective study, ketamine was 1mg/kg) reduces pain scores & postop opioid consumption vs morphine PCA alone.
PCA should be reserved as rescue or step-down analgesia however may be useful combined with a plain epidural in situations where the epidural catheter can’t adequately cover the incisions (eg. large midline laparotomy or cervical incision).
Other adjuncts (eg, gabapentin?)

G: PPI for major surg.
Early initiation of feed.

Monitors:
BIS
NMT
Cardiac output monitoring w minimally invasive methods recommended, for optimisation of SV before the thoracic phase & for 12hrs after the operation- can’t use oesophageal doppler or TOE so consider PiCCO or LiDCO- but these monitors can’t provide validated readings during the thoracic phase so should avoid aggressive fluid loading @ that point.
invasive arterial BP
CVC if w

Question 11

Where are the incisions for a McKeown technique? Rationale for this?

Answer 11

Tri-incisional- cervical incision for the upper anastomosis (rationale= the upper incision is performed @ a site which hasn’t been subject to previous radiotherapy (if used) & also it’s technically easier to insert a cervical drain)), thoracotomy & laparotomy.

Question 12

When is a colonic transposition oesophagectomy indicated? issues with this?

Answer 12

For revision oesophagectomy. Colonic interposition performed using a section of colon on a pedicle. High risk due to hostile surgical field & multiple vulnerable anastomoses.

Question 13

What’s the incision for the transdiaphragmatic oesophagectomy?

Answer 13

The incision extends from the thoracotomy site to the umbilicus, dividing the diaphragm surgically.

Question 14

What’s the classical approach to transhiatal oesophagectomy? when is this done & what are some issues with it?

Answer 14

laparotomy & cervical incision. May be done for lower oesophageal tumours where thoracotomy undesirable, eg. those who’ve had previous thoracic surgery. Dissection of the lower oesophagus occurs through enlarged diaphragmatic hiatus then the re-anastamosis is done via the cervical incision.
Dissection around mediastinum may be associated with arrhythmias & ventricular compression causing hypotension but this can rarely occur during the thoracic stage of other oesophagectomies too.

Question 15

What does minimally invasive oesophagectomy involve?

Answer 15

Thorascopic & laparoscopic surgical techniques.
Often a hybrid approach is used with open + laparoscopic or thoracoscopic techniques.

Question 16

What are some concerns for the unventilated & ventilated lung during OLV? And cardiovascular challenges? preferred ventilation strategy for OLV?

Answer 16

Deflated lung: vulnerable to atelectotrauma & ischemia-reperfusion injury
Ventilated lung: risks volu- & baro-trauma, high FiO2
Cardiovascular: challenge of shunt & raised pulmonary artery pressure
Low TV, lung-protective strategies are preferred for OLV.

Question 17

What organ system is the source of highest complication rate after oesophagectomy? What factors can help limit? What’s the incidence of RLN palsy & particularly relevant complications of it?

Answer 17

Pulmonary
Intraop lung-protective ventilation (reduces ARDS risk), exquisite fluid balance, adequate analgesia intra- & post-op, complete reversal of NMB, normothermia, haemodynamic stability
Postop chest physiotherapy, early mobilisation
RLN palsy occurs in anything from 4-67% of pts- it’s most often transient, it’s detection may be delayed as the early postop vocal fold oedema resolves & hoarseness is unmasked.
RLN palsy predisposes to inadequate cough & aspiration risk

Question 18

If a pt develops ARDS after oesophagectomy, what postop complications should be considered?

Answer 18

occult anastomotic leak or sepsis

Question 19

What may be concerns with NIV soon after upper GI surgery?

Answer 19

high airway pressure may be transmitted to the gastric conduit & may compromise the anastomosis. insufficient data to indicate if NIV safe.

Question 20

What’s the major surgical complication after oesophagectomy? What principles reduce this risk?

Answer 20

anastomotic leak- serious & may account for 35% of periop mortality.
Avoiding tissue oedema & vasoconstriction will assist perfusion to the anastamosis, which is vulnerable to ischemia (& inadequate healing or breakdown) as distant from origin of it’s blood supply.

Question 21

When do minor & major leaks usually occur following oesophagectomy?

Answer 21

Major leaks present in the first 5/7 w severe sepsis but may be occult.
Minor leaks often manifest after 1/52 w local neck infection, collections or pleural effusions.

Question 22

What types of arrhtyhmias are frequent after oesophageal surgery?

Answer 22

supra ventricular, esp AF, they’re associated with increased mortality risk.
May be due to direct contact from the Tx dissection or pericardial irritation or due to postop anastomotic leak, sepsis or raised RAP after OLV.

Question 23

Endoscopic deployment of stents to alleviate dysphagia usually requires what type of anaesthesia?

Answer 23

conscious sedation

Question 24

What are some benefits of the NGT postoperatively after oesophagectomy? Do they increase the risk of aspiration?

Answer 24

Decompress the conduit, protect the anastamosis, allow identification of bleeding & monitor GI secretion volume
They don’t increase the risk of aspiration

Question 25

For which surgical approach to oesophagectomy is one-lung ventilation not required?

Answer 25

Transhiatal (which has laparotomy & L) cervical incision but no thoracotomy)

Question 26

While they could theoretically be useful for chronic pain, what’s the limitation of using gabapentin, pregabalin or TCAs for a pt with marked dysphagia or those early following oesophagectomy?

Answer 26

not available in parenteral form

Question 27

What is the evidence for epidural analgesia after thoracotomy?

Answer 27

Level 1 (Cochrane R/V) evidence that it reduces incidence of chronic post surgical pain 3-18 months after thoracotomy cf systemic analgesia w NNT=7

Question 28

What is the evidence for thoracotomy vs PVB following thoracotomy?

Answer 28

Level 1 evidence that they provide comparable analgesia at rest & after coughing, PVB has superior minor complication risk (eg. hypotension, N&V & urinary retention)

Question 29

What are some factors increasing the risk of post-thoracotomy, post-mastectomy, post-herniotomy & post-hysterectomy pain syndromes?

Answer 29

psychological factors (anxiety, catastrophising)
Chronic preoperative pain
severe acute postoperative pain

Question 30

What’s the incidence of any CPSP & severe CPSP after thoracotomy? what proportion is neuropathic?

Answer 30

5-65%, 10%, 45%

Question 31

What’s the incidence of CPSP after VATs?

Answer 31

13-35%- so lower risk than thoracotomy but still an issue

Question 32

Are the analgesic benefits of thoracic epidural best if instigated pre- or post-op?

Answer 32

Level 1 evidence shows improved acute pain with coughing when the thoracic epidural instigated pre-emptively vs post-op.
Level II evidence shows pre-emptive Tx epidural also associated w lower pain scores, reduced inflammatory biomarkers & shortened hospital LOS.

Question 33

For which procedures have meta-analyses demonstrated a role for regional anaesthesia in prevention of CPSP?

Answer 33

Thoracotomy, breast Ca surgery & caesarean

Question 34

For which patients have intrathecal morphine infusions been described?

Answer 34

burns pts in the ICU, post-thoracotomy

Question 35

Does adding a low-dose IV ketamine infusion for 24-48hrs postop enhance the analgesia from epidural following thoracotomy?

Answer 35

the Level II data is conflicting

Question 36

Has periop gabapentin been shown to reduce epidural requirements & pain scores after thoracotomy?

Answer 36

no

Question 37

Does epidural dexmedetomidine provide enhanced pain relief compared to IV dexmed for open thoracotomy? at what doses? what are some other benefits? what are adverse effects?

Answer 37

Yes- at 0.5microg/kg single-shot
Also reduces postop shivering
Minimal decr HR & incr sedation score

Question 38

Is high or low concentrations of LA better for PCEA after thoracotomy?

Answer 38

low
level II evidence has demonstrated that PCEA with high (0.5%) & low (0.15%) [] levobupivacaine show no differences in quality of analgesia, morphine consumption or pt satisfaction

Question 39

What are the 3 main anaesthetic considerations for most oesophageal surgery?

Answer 39

risk of pulmonary aspiration, usually require OLV & postop pain management

Question 40

At what levels are thoracic epidural catheter placed for oesophagectomy?

Answer 40

T5-6 for the thoracotomy, T7-8 for both abdo & thoracic incisions; sometimes 2 placed if large midline incision.

Question 41

What are alternative regional anaesthesia techniques other than TEA or PVB for oesophagectomy?

Answer 41

ESP,SAP, pecs, intercostal, TAP blocks, intrathecal opioid. Supplemental PCA may be required for these cases.

Question 42

Which ANZCA PS is the guideline on monitoring during anaesthesia? What’s the gist?

Answer 42

18
Monitoring must always be used in conjunction with careful clinical observation
Visual & audible alarms on anaesthesia equipment must be enabled & audible @ commencement of anaesthesia & only disabled under exceptional circumstances (eg. cardiopulmonary bypass) & the alarms should be made operational as soon as practicable
Regular recordings should be documented
Anaesthetist must be present constantly from induction of anaesthesia until safe transfer to pacu or ICU. If brief absence is necessary in exceptional circumstances, pt observation, recording & responding to significant perturbations to physiological variables can be delegated to a suitably trained & skilled practitioner judged competent for the task.
Regular assessment & monitoring of:
oxygenation- adequate lighting must be available to aid with assessment of pt colour
Ventilation must be continually monitored
circulation: by detection of arterial pulse, supplemented by BP monitoring. Intervals btwn recording must be no less frequent than 10-minutely (if BP omitted the decision must be clinically justified)

Oxygen:
-For all pts using an anaesthesia breathing system, a device incorporating an audible signal to warn of low O2 [] must be in continuous operation.
-Pulse oximeter must be used for every patient undergoing GA or sedation with appropriately audible variable pulse tone & low threshold alarm.

Ventilation:
-Whenever automatic ventilator used, an automatically activated ventilator disconnection or failure alarm must be in continuous operation.
-A monitor of the CO2 level in inhaled & exhaled gases must be in use for every pt undergoing GA & must be immediately available for any pt undergoing sedation

Cardiovascular:
-Continuous ECG monitoring must be immediately available for every anaesthetised pt. It must be used for all pts undergoing GA or major regional as clinically indicated.
-NIBP must be available for every pt undergoing anaesthesia & a variety of cuff sizes must be available.
-Continuous invasive arterial BP monitoring should be available.
-Must have inhalation anaesthetic agent monitor for every pt undergoing inhalation anaesthetic
-monitor of anaesthetic effect on the brain used where clinically indicated esp for pts @ high risk of awareness, during GA
-continuous temp monitoring must be available for all pts undergoing GA & it should be used whenever warming devices are used
-quantitative NM function monitoring must be available for every pt for whom NM blockade has been induced & should be used whenever considering extubation following use of a NDNMBD
-other equipment should be available as clinically indicated (eg. CVP, cerebral oximetry, TOE)

Question 43

What’s the most common pattern of oesophageal Ca mets?

Answer 43

LN, lung, liver, bones, Adr, brain

Question 44

What does the RELIEF trial say about liberal (6L) vs restrictive (3.7L) periop fluid during & up to 24hrs post major abdo surgery?

Answer 44

restrictive not associated w higher disease-free survival but is ass’d w higher risk AKI vs liberal.

Question 45

What are the particular considerations, specific anaesthetic management issues, options for perioperative analgesia & perioperative fluid therapy for PANCREATECTOMY?

Answer 45

4P’s:

PATIENT: pancreatic cancer should be considered in elderly pts presenting for first time with pancreatitis; nonspecific abdo pain +/- jaundice, weight loss, steatorrhoea, gastric outlet obstruction (nausea, satiety)
risk factors: age, smoking, ETOH, raised BMI, DM, chronic pancreatitis, periodontal disease, familial cancer syndromes

PATHOLOGY: Pancreatic cancer typically has late presentation (10-20% have resectable Ca @ time of presentation), early metastases & poor survival rates (surgery for pancreatic adenocarcinoma with curative intent has 10-15% 5-year survival, median survival of 11-18 months)
Malignancy- 4M’s; pt may have neoadjuvant or adjuvant chemotherapy to increase incidence of disease-free resections & reduce local recurrence. For metastatic PC, chemo may occur to slow tumour growth & offer symptomatic benefit, along with radiotherapy.
Pancreatic neuroendocrine tumors include insulinoma, glucagonoma, pheochromocytoma, carcinoid (vasoactive substances eg., serotonin- may develop carcinoid syndrome with flushing of head/upper thorax, diarrhoea, bronchoconstriction, carcinoid heart disease (serotonin induces fibrosis in valves)- Rx with octreotide infusion).

PROCEDURE:
-Resection is the most effective Rx (only Rx with curative potential) for early-stage cancers. Complex procedure- multi-D planning vital.
-Most tumors that are associated with pancreatic head, neck & uncinate process require pancreaticoduodenectomy (Whipple’s, has 3 anastamoses), involving resection of proximal pancreas, distal stomach, duodenum, distal bile duct & gall bladder as an en bloc specimen, intestinal continuity via gastrojejunostomy or other anastamosis.
Incision upper transverse generally (need analgesia T5-8)
Initially, abdo assessed for metastatic disease
mobilise duodenum, head of pancreas & isolate the SMV. mobilise stomach & remainder of duodenum.
skeletonize the porta hepatis
remove GB, transect common hepatic duct
mobilise & transect prox jejunum
neck of pancreas transected & the attachments of the specimen to the SMV, PV & SMA are divided.
GI recon is accomplished by providing drainage of the pancreatic stump & CHD, restoring GI continuity.

-Pylorous-preserving pancreaticoduodenectomy omits resection of the pylorus; depends on surgical & oncological factors; less radical, preserves gastric antrum, pylorus, prox 3-4cm of duodenum.
Benefits of pylorus preservation= decr incidence of postop dumping & bile reflux gastritis that can occur w partial gatrectomy.
provides significantly reduced OT time, transfusion & blood loss but but incr risk delayed gastric emptying if pylorus-preserving cf conventional whipples.
-Distal pancreatectomy is for tumours of body & tail of pancreas- involves resection of spleen given it’s close proximity to pancreas tail (pt requires lifelong ABx & vaccination against encapsulated bacteria)
-Some small tumors or tumors of the distal pancreas may be laparoscopic (shorter time to PO intake, shorter hospital stay)
-palliative pts may receive stents for bile duct (via ERCP or percutaneous trans-hepatic cholangiography) or duodenal (via gastroscopy) obstruction, bypass surgery )(if advanced inoperable tumour detected during exploration; gastro-jejunostomy to relieve duodenal obstruction & hepatico-jejunostomy to relieve biliary obstruction) or coeliac plexus block, to improve symptoms & quality of life

POTENTIAL COMPLICATIONS:
Bleeding- may have major blood vessel involvement
Whipples has 3 anastomoses; risk ileus, anastomotic leak, pancreatic fistula formation.
wound & chest infection.
Can develop exocrine insufficiency following pancreatic resection–> fat malabsorption, may require pancreatic enzyme supplements
Postop diabetes- rarely produces ketoacidosis & pts are sensitive to exogenous insulin. more common if total pancreatectomy (rare as no evidence vs whipples or PPPD) unless islet cell transplant

Pre-OP (COPED):

CONSULT:
pt selection important given complex surgery; absolute contraindications for pancreatic resection= distant mets or pt deemed unfit for surgery
Risk stratification: P-Possum intended to predict morbidity & mortality in general surg setting (not validated for pancreatic surgery).
Hx
Ex
Ix: normochromic anaemia (haematinics if present), thrombocytosis, elevated bilirubin (conjugated & total), ALP & GGT
Consider pre-op NT-pro-BNP for pts aged >=65, 45-64 with significant CV disease or if RCRI>=1 (to monitor for MINS)
consider resting TTE if heart murmur or cardiac symptoms or S&S of heart failure
resting ECG

CEA 19-9 has sensitivity 80% & specificity 73% for PC
Pt will have had CT & EUS for Dx & prognostication, PET scan can detect distant METs
Multi-D discussion with surgeon re: images- pancreatic tumours may involve major blood vessels

OPTIMISE:
Multi-D involvement however limited time as time-sensitive surgery for aggressive Ca
Smoking & ETOH cessation
improve or maintain fitness
preop nutrition (these pts universally malnourished- dietician involvement)
Optimise red cell mass- consider Fe if ferritin <100microg/L or Tsat <20%- usually IV (time-sensitive OT)

PREMED/PLANNING:
Multi-D, pt selection, tertiary centre, ERAS principles may accelerate recovery (reduce stress response, improve immune function, optimise pain control, early resumption of diet & mobilisation for more rapid recovery & discharge; multimodal, multi-D)
Early on list, minimise fasting, pre-op carbohydrate drink in pts without diabetes

EXPLAIN/CONSENT:
PREOPERATIVE COUNSELLING- reduce anxiety, enhance recovery & discharge
Procedures, high risk surgery (mortality <5% but morbidity 20%), post-op ICU

DISPOSITION:
ICU

Intraop: MADE (T)-PRIME

MONITORING:
12-lead ECG
art line awake, NIBP 30-minutely
SpO2
Temp-probe IDC
BIS
NMT

ASSISTANT:

DRUGS:
-multimodal, opioid-sparing analgesia (thoracic epidural T5-8 for upper transverse incisions (reduced stress response, superior postop analgesia, decreased pulm or cardiac morbidity, earlier return intestinal function, reduced thromboembolic complications) OR intrathecal morphine + lignocaine infusion + TAP catheters (POP-UP study: continuous wound infiltration w PCA non inferior to epidural in HPB surgery); ketamine; paracetamol; parecoxib; dexamethasone; fentanyl titrated)
-TIVA- oncoanaesthesia principles
-anti-emetics (ERAS principles)

EQUIPMENT:

Warming (PRE-WARM PT)

INDUCTION PLAN:

perform thoracic epidural or ITM- ideally avoid sedative premed (ERAS) if pt limited anxiety; reassuring demeanour, non-pharmacological anxiolytics

large-bore IV awake, CVC asleep; avoid premed due to ERAS principles, fentanyl 1-2mcg/kg, lignocaine 1mg/kg, alf 10-20cmg/kg, propofol 0.5-2mg/kg, roc 0.6mg/kg unless RSI

AIRWAY: Pre-O2, cuffed ETT ready, consider RSI if pt has gastric outlet obstruction

VENTILATION PLAN: lung-protective (long case)

CIRCULATION:
Bleeding risk; large-bore IV access, valid group & hold, consider blood immediately available +/- cell saver (with leucodepletion filter) + vascular involvement if tumor involves large vessels
Transfusion thresholds pre-established
MAP goal within 20% of baseline; titrate vasopressors to achieve this

DISABILITY:
Pressure points padded (long case)
Maintain with propofol TIVA, BIS
ABx prophylaxis- repeat 4-hourly
thromboprophylaxis (TEDs, SCUDs, hydration)

EXPOSURE:
pre-warm, normothermia intra-op

FLUIDS:
urine output 0.5-1mL/kg/hr- neutral fluid balance, could monitor with haemoconcentration or lactate

GLUCOSE monitoring with ABG

POSTOP (RAWF):
RECOVERY: extubate in OT
ANALGESIA: consider PCA with ongoing epidural infusion, goal= early mobility D1
DISPOSITION: ICU
FOLLOW-UP: acute pain service- I R/V my epidurals
thromboprophylaxis

Question 46

What are the main functions of the pancreas?
How much pancreatic juice is secreted daily (exocrine)? contents?
And what cells are responsible for endocrine function?

Answer 46

aid digestion & bel control

1500mL- digestive proteolytic enzymes

endocrine cells form the islets of Langerhans; B cells (insulin), alpha cells (glucagon), D cells (somatostatin), F cells (pancreatic polypeptide)

Question 47

What’s Whipple’s procedure?

Answer 47

Necessary for most tumors involving pancreatic head, neck & uncinate process; pancreaticoduodenectomy, involving resection of proximal pancreas, distal stomach, duodenum, distal bile duct & gall bladder as an en bloc specimen

Question 48

What do pts require following splenectomy?

Answer 48

lifelong antibiotics
vaccination against encapsulated bacteria

Question 49

How do epidural vs ITM with PCA compare for hepatic resection?

Answer 49

non-inferior

Question 50

If a concern re: anastomotic leak after pancreatic resection, what should be measured?

Answer 50

amylase [] in drain output (>100IU/L confirms Dx)

Question 51

Adrenelectomy, incl phaeochromocytoma

Answer 51

Key points for phaeo:

Phaeochromocytomas are neoplasms of chromaffin tissue that synthesises catecholamines.

high-risk surgical procedure (need experienced anaesthetist/surgeon)

main issue= labile BP, arrhythmias & tachycardia during & after surgery.

Pts with unrecognised pheochromocytoma undergoing anaesthesia for unrelated surgery are higher risk= unexplained severe HTN, tacchy, arrhythmias, CV collapse; mortality in this situation approaches 80%. eg. after metoclopramide (CONTRAINDICATED IN PHAEOCHROMOCYTOMA, IT STIMULATES CATECHOLAMINE SECRETION from PHAEOCHROMOCYTOMAS!)

other drugs increasing sympathetic tone (eg, ketamine, ephedrine, pancuronium) should not be used, as should histamine-provoking drugs (morphine, atracurium).
must have ADEQUATE ADRENERGIC BLOCKADE (phenoxybenzamine) & volume expansion prior to OT, with goals of normal HR, BP & urine output throughout surgery; haemodynamic stability vital.

Surgeon should communicate ++ esp w incision, time of division of venous supply & during tumour manipulation.

Pt must have art line. If heart failure or decr cardiac reserve, consider CVC +/- monitoring of pulmonary pressures. large-bore access & urinary catheter (to monitor fluid balance).

haemodynamic lability (particularly during phase 1 prior to clamping of effluent vein, with laryngoscopy/incision/pneumo, with agents with sympathomimetic properties; risk hypoT phase II after drop in endogenous catecholamines & esp if long-acting alpha blocker on board or TEA with LA)

Adrenalectomy indications? steps?

What are some considerations for resection of a catecholamine-secreting tumour (eg. paraganglioma secreting metanephrine)?

Adrenalectomy indicated for benign & malignant tumours; for alodsteronomas, phaeochromocytomas, cortisol-secreting tumours, adrenal incidentalomas.

PATIENT:

adrenal incidentalomas more common in pts w HTN, obesity, diabetes
bilateral masses can be seen if mets (eg. pulmonary), congenital adrenal hyperplasia, cortical adenomas, ACTH-dependent Cushing’s, pheochromocytoma, primary aldosteronism, amyloidosis.

Medications:
What’s phenoxybenzamine: non-selective, non-competitive, long-acting alpha blocker. May be responsible for refractory postop (catecholamine-resistant) hypoT so generally stop 24-48hrs before surgery due to long half-life. Pts may require BP support postop. May also cause a reflex tachycardia due to uninhibited norepinephrine release from cardiac sympathetic neurones via B1 stimulation, due to it’s pre-synaptic alpha 2 blockade interfering with NE -ve feedback loops. central alpha 2 blockade also –> somnolence, headache, nasal congestion.
What’s doxazosin? competitive, selective alpha1 blocker. shorter-acting. Doesn’t cause tachycardia or sedation, may reduce incidence of postop hypotension cf phenoxybenzamine. prazosin is another selective competitive alpha 1 blocker, short-acting.

Investigations:
CT: lower attenuation suggests more lipid & more likely benign. benign tend to be more homogenous, sharper margins, smaller, unilateral. phaeochromocytomas have increased mass vascularity, high attenuation, may be uni or bilateral. carcinoma tends to e irregular, unilateral, larger. mets tend to be bilateral.

24-hour urine normetanephrine & metanephrine or plasma fractioned metanephrines assesses for pheochromocytoma. must assess for it before do an FNA biopsy of adrenal mass since biopsying a phaeo risks hypertensive crisis or haemorrhage.

biochemical testing of adrenocortical hyper- and hypo function:

most adrenal incidentalomas are nonfunctional
The 3 tests of hyperfunction:

1. glucocorticoid secretion (subclinical cushing’s syndrome- assess with dexamethasone suppression test
2. pheochromocytoma (measure the 24hr urine fractioned metanephrines or plasma metanephrines if high CT attenuation; consider resection of nonfunctioning lipid-poor vascular adrenal masses since small phaeos may have normal biochem testing (need a critical mass before biochem detectable))
3. primary aldosteronism (consider if HTN, hypokalaemia associated; measure plasma aldosterone & renin)

PROCEDURE:

approach most commonly transabdominally (open (flat supine if bilat, supine flank elevated for unilateral, incision is either upper midline, subcostal or Makuuchi (optimises exposure & minimises denervation of abdo wall)) or minimally invasive, this is LATERAL on inflatable beanbag, pt rotated back 15deg), can also approach retroperitoneally (posterior, either open or laparoscopic (retroperiteneoscopic adrenelectomy). prone & hips/knees flexed 90 deg. If unlat, slight tilt in prone, if bilateral pure prone) or transthoracically. Thoracoabdominal is rare- large tumours with diaphragm involvement or extension of tumour into chest.

Basic principles=
wide exposure & visualisation of operative field
meticulous isolation & control of major vascular structures
precise adrenal gland & tumour resection using en block technique to avoid capsular rupture

Data inconsistent regarding minimally invasive vs open for adrenocortical carcinoma. MIS is the gold standard for small benign adrenal masses (reduced blood loss, fewer intraop complications, less pain, earlier pt mobility & recovery, decreased LoS). Tumours >10cm more likely to be malignant & have technical difficulties w MIS so should perform open for any adrenal lesion >10cm or with appearance of local invasion. open for primary adrenal malignancy of any size.

Retroperiteoscopic adrenelectomy advantageous if surgical expertise available (it’s a small area, technically challenging, may need insufflation up to 20mmHg to create working space in retroperitoneum) for bilateral adrenelectomies (intraop repositioning not required), great if pt has had multiple prev abdominal procedures (no need to mobilise abdo organs), no intraperitoneal insufflation) but it’s unsuitable for obese pts or if suspect malignant tumour or invasion into adj structures)

pheochromocytoma can be removed laparoscopically when safe & feasible but surgeon must be prepared to go open if intra-op bleeding (PHAEOCHROMOCYTOMAS ARE HYPERVASCULAR) or capsule violation (HYPERTENSIVE CRISIS RISK).

2 main phases of phaeochromocytoma resection: close communication vital to allow anticipation haemodynamic changes during surgery.
Phase 1= tumour dissects & vascular supply isolated (BEFORE effluent vein clamped). Risk severe episodic HTN, arrhythmias due to adrenal manipulation. phase 1 also involves laryngoscopy, endotracheal intubation, peritoneal insufflation (particular risks catecholamine release due to compression of the tumour, changes in tumour blood flow, SNS response to hypercapnia), tumour manipulation (highest BP recordings).

Phase II: effluent vein clamped. precipitous hypotension can occur (sudden drop endogenous catecholamines & chronic down regulation of alpha-adrenoceptors, presence of alpha-blocking meds, IV volume depletion; often need vasopressors.
open for large or invasive phaeo & for paragangliomas, which are rare NETs arising from extra-adrenal autonomic paraganglia. Sympathetic paragangliomas secrete catecholamines & are clinically like phaeochromocytomas (HTN, episodic headache, sweating, tachycardia) & histologically indistinguishable from phaeochromocytomas. Parasympathetic paragangliomas are nonfunctional. Most (2/3) are sporadic rather than part of an inherited syndrome.

POTENTIAL COMPLICATIONS:
bleeding: particular risk for tumours that abut/invade IVC; such tumours should have open trans abdominal approach w extended R) subcostal incision to facilitate immediate access & control o the IVC in event of vascular injury.
capsule rupture: spillage of tumour cells, so complete resection may involve en bloc excision of surrounding structures.
haemodynamic lability
pressure/positioning injuries (eg. lateral or prone)
infection
VTE
after phaeo:
haem swings
hypoglycaemia
adrenal suppression (bilat adrenelectomies)- lifelong glucocorticoid replacement for bilateral
renal failure

Pre:

multi D evaluation & management for pheochromocytoma (surgeon, anaes, endocrine) with senior involvement

Goals in pre-admission clinic=

1. evaluate for end organ damage due to excess catecholamine secretion (classic triad of symptoms= headache, sweating, palpitations; HTN in 90% may be paroxysmal; most phaeo pts don’t present with all 3. Other less common S&S= orthostatic hypoT, blurred vision, papilloedema, weight loss, polyuria, polydipsia, constipation, anxiety, lethargy, nausea, tremor. may get abdo pain from bowel ischaemia (excess VC)
   -end-organ damage, largely from vasoconstriction, hypoperfusion & unmatched O2 demand:
   -CNS: encephalopathy, CVA
   -CVS: end organ effects of this system the most significant for anaes, may be due to direct effect of catechols vs HTN alone: arrhythmias, angina, infarction, acute failure, cardiomyopathies (incl acute takotsubo, chronic); coronary spasm, +ve inotropy & chronotropy. Aortic dissection, limb or organ ischaemia may occur. volume depletion & postural hypoT
   -kidneys: acute renal failure, haematuria (hypoperf, VC, unmatched O2 demand)
   -lungs: ARDS, pulm oedema (ass’d w cardiac decompensation, incr permeability)
   -GIT: intestinal ischaemia
   -ocular: blindness, retinopathy

Pre-op ECG looking for rhythm disturbances, ischaemic changes; generally resolve w medical preparation but may delay OT until active ischaemia & arrhythmias adequately controlled.
pre-op echo to assess ventricular function, chamber size, wall motion: takutsubo cardiomyopathy (induced by catecholamines) is often reversed with pre-op optimisation.

Standard G&S, CBC, EUC, BGL.

if phaeo, catecholamine levels (higher= higher risk haem instability but still a risk even if normal hormone levels)

CXR for cardiomegaly, pulm oedema.

Ix re: tumour size (larger= higher risk haem instability intraop), location (implications re: blood loss (higher risk phaeo)

2. evaluate the pre-op medical preparation, particularly whether it’s achieved it’s goals of controlling HTN (helping reduce hypertensive crises during surgery & help improve cardiac function prep) & normalising intravascular volume; all pts w catecholamine-secreting neoplasms require pre-op pharmacologic preparation.anaes R/V 7-14 days prior to resection to allows for Rx modification, endocrine will have titrated therapy aimed @ minimising physiologic impact of catecholamine release (pre-op medical therapy takes 10-14days; initially alpha blocker phenoxybenzamine or doxazosine 10-14 days pre-op, add-on CCB if needed, then (3-4 days later) consider cautious introduciton of B blocker generally propranolol, if tacchycardia/arrhythmias).
   PRE-OP OPTIMISAITON AIMS TO CONTROL HTN & TACCHY
   VOLUME EXPANSION
   Goals generally are seated BP 120/80, standing >=90mmHg, HR 60-70bpm sitting & 70-80 standing. Generally prep involves alpha blockade (initiated first) then if tachycardia or arrhythmias, add B blocker, cautiously, several days pre-op (eg. useful if tumour secreting large amounts epinephrine; short-acting metoprolol low dose to commence, caution if pts have catecholamine-induced cardiomyopathy (or as usual CCF, asthma)). CCBs may be added to supplement or if intolerable side effects but may cause hypotension.
   metyrosine= a competitive inhibitor of tyrosine hydroxyls (rate-limiting enzyme in catecholamine formation). 5-day pre-procedure preparation protocol; main side-effect= hyper somnolence.

AVOID:
-metoclopramide
-high-dose cortiosteroids
-histamine
-glucagon
B blockers without alpha blocker
may all precipitate phaeochromacytoma paroxysm

3. anticipate how the pre-op medical therapy may impact intra- and post-op events, ensure appropriate medication advice given (eg. w/h phenoxybenzamine)

Other history, including hereditary conditions associated with pheochromocytoma (von Hippel-Lindau, NF-1, MEN2)

Diabetes (also factor for intraop haemodynamic instability), DM common in pheochromocytoma (catechol-induced insulin resistance or suppression).

It’s extremely rare for pts w phaeo to present in extremis (pheochromocytoma crisis); HTN or hypoT, hyperthermia (temp >40deg), mental status changes, other organ dysfunction. emergency pheochromocytoma resection has high mortality.

Plan for tertiary, early, daylight hours, endocrine liaison, postop HDU

Pt-centred discussion re: plan & risks

Intra:

Monitoring:
5-lead ecg, SpO2, NIBP, art-line pre induction (post anxiolysis) BIS, NMT, temp probe IDC. CVC for vasoactive infusions (post intubation, pre positioning & incision). consider TOE if significantly depressed cardiac function.

A:

Drugs:
Have vasopressors, vasodilators & anti arrhythmic meds prepared in advance, ready for immediate administration. Choose agents with ease of titration, rapid effect & quick offset to respond to changing haemodynamic conditions.

premed with midaz to help with line placement.

consider pre-op epidural (only for open) but this may exaggerate phase II hypoT esp if phenoxybenzamine also on board or pre-op B blockers.

Alt= place it & give a test dose but don’t use it during surgery to avoid sympathectomy; could titrate dilute opioids +/- LA along with vasopressors from closure.
titrating vasodilators (haem lability a particular risk w adrenalectomy for phaeo)
hydrocortisone for pts with adrenelectomy for Cushing syndrome (50-100mg on removal of adrenal gland)
cefazolin
VTE prophylaxis (esp if cushings, frequent hypercoaguability)
aggressive anti-emesis (N&V common w adrenalectomy)
AVOID ketamine, metoclopramide, glucagon (promotes release of catecholamines from the tumour), halothane, ephedrine (avoid until tumour excised, large doses of droperidol, haloperidol. avoid chlorpromazine & prochlorperazine (pts w phaeo susceptible to their hypotensive effects, mechanism unknown). Theoretically, best to avoid drugs releasing histamine (morphine, atracurium).
-consider insulin if required to control BGL (catecholamine-induced insulin resistance or suppression resolves after tumour removal)

Equip:

Pre-O2:

Induction: heavily blunt the SNS response to intubation, incision, insufflation; fentanyl boluses, lignocaine, propofol, NDMA.

Maintenance:
excellent communication w surgeon, substantial intra-op haemodynamic instability common irrespective of pre-op catecholamine levels or pre-op alpha adrenergic blockade
phase I aim SBP 100-160mmHg
If significant swings, immediately notify surgeon, OT may need to be paused to allow regain control, Rx begins immediately, I must be able to counter alpha- and beta-adrenergic catecholamine-induced cardiovascular effects with short-acting meds (nitroprusside, phentolamine, nicardipine, esmolol) & communicate w surgeon if these methods are needed & when discontinued.
-nitroprusside immediate onset, ultrashort-acting VD (venous & arterial, reflex SNS +, attenuate reflex tacchy w esmolol infusion), useful for intraop HTN crisis; protect from light, infusion, start at 0.5cmg/kg/min or bolus 20mcg (if long infusion max 3mcg/kg/min; risk CN toxicity, CN binds cytochrome oxidase—> oxidative phosphorylation prevented—> tissue anoxia, lactic acidosis. first signs= tachyphylaxis, metabolic acidosis, incr PmvO2. Rx= stop SNP, 100% O2, give sodium thiosulfate (sulfur donor, convert CN—> thiocyanate). also sodium nitrate converts Hb to metHb so can get more cyanometHb. give vit B12 (binds CN). methylene blue for MetHb—> Hb. can clear thiocyanate w dialysis.
-phentolamine: nonselective alpha blocker, give 1mg test dose then can give 5mg or 0.5mg/min infusion. reflex tachy risk.
-nicardipine: CCB, 5mg/hr to max 15mg/hr.
-labetalol (5-20mg, alpha & b blocker)
-esmolol: 10-50mg bolus, infusion 25-250mcg/kg/min
-Mg++: vasodilator, inhibits catecholamine release from ada medulla, antagonises alpha-adrenergic receptors, Ca++ antagonist, anti arrhythmic. bolus IV 2-4g over 20 mins, 1-2g/hr infusion. discontinue once venous drainage from tumour ligated or tumour removed. potentiates NMBAs (monitor)
-for arrhythmias, IV lidocaine, esmolol, amiodarone (esp if impaired cardiac function)

-for hypoT, aggressive IVT, discontinue vasodilators, phenylephrine (pure alpha, short half-life, boluses 50-100mcg, infusion 20-200mcg/min). avoid ephedrine before tumour removal. norepinephrine (2-20mcg/min). vasopressin (0.03-0.04U/min)for refractory hypotension after tumour removal, particularly after significant blood loss or if pt had extremely high prep catecholamines.
Post:
PCA

Emergence:
extubate
Postop ICU for monitoring of complications:
-continuous haemodynamic monitoring: BP, HR
-BGL monitoring: hypoglycaemia common due to rebound incr insulin secretion (suspect if pt slow to emergenc
e from anaes or are lethargic postop)
-adrenal insufficiency if bilat adrenelectomy: these pts need glucocorticoid replacement: hydrocortisone 100mg with induction, 100mg every 8 hrs for 24hrs, taper over 3 days, pts w bilateral adrenalectomy need lifelong steroid replacement.
-renal failure common after phaeo resection, massive catechol release may cause renal hypoperfusion/ischaemia or may be AKI due to hypoT/
(bleeding risk & infection risk)