Post-operative complications Flashcards
What are 5 causes of early post-op pyrexia (0-5 days)?
- Blood transfusion
- Cellulitis
- Urinary tract infection
- Physiological systemic inflammatory reaction (usually within a day following the operation)
- Pulmonary atelectasis (lung collapse)
What are 5 late (>5 days) causes of post-op pyrexia?
- Venous thromboembolism
- Pneumonia
- Wound infection
- Anastomotic leak
What is paralytic ileus?
Common complication after surgery involving bowel, especially surgeries involving handling of bowel. No peristalsis, resulting in pseudo-obstruction
What are 4 causes of paralytic ileus excluding surgery?
- Chest infections
- Myocardial infarction
- Stroke
- Acute kidney injury
What are 3 things to test in the blood that should be done in cases of paralytic ileus, and what should be done in response?
- Deranged electrolytes can contribute to development of paralytic ileus, therefore check: potassium, magnesium, phosphate.
- Replace electrolytes intravenously, as bowel not functioning normally
What are 9 ways of averting surgical complications?
- WHO checklist
- Prophylactic antibiotics
- Assess DVT/PE risk, prophylaxis
- Mark site of surgery
- Use tourniquets with caution
- Remember danger of end arteries and in situations where they occur, avoid using adrenaline-containing solutions and monopolar diathermy
- Handle tissues with care - devitalised serves as nidus for infection
- Wary of coupling injuries when using diathermy during laparoscopic surgery
- Inferior epigastric artery is favourite target for laparoscopic ports and surgical drains
What is a common mechanism for injuring the accessory nerve?
Posterior triangle lymph node biopsy
What is a common mechanism for injuring the sciatic nerve?
Posterior aproach to hip
What is a common mechanism for injuring the common peroneal nerve?
Legs in Lloyd Davies position
What is a common mechanism for injuring the long thoracic nerve?
Axillary node clearance
What is a common mechanism for injuring the recurrent laryngeal nerve?
During thyroid surgery
What is a common mechanism for injuring the pelvic autonomic nerves?
Pelvic cancer surgery
What is a common mechanism for injuring the hypoglossal nerve?
During carotid endarterectomy
What is a common mechanism for injuring the ulnar and medican nerves?
During upper limb fracture repairs
What is a common mechanism of injury to the thoracic duct?
During thoracic surgery e.g. pneumonectomy, oesophagectomy
What is a common mechanism of injury to the parathyroid glands?
During difficult thyroid surgery
What is a common mechanism of injury to the ureters?
During colonic resections/ gynaecological surgery
What is a common mechanism of injury to cause bowel perforation?
Use of Verres needle to establish pneumoperitoneum
What is a common mechanism of injury to the bile duct?
Failure to delineate Calots triangle carefully, and careless use of diathermy
What is Calots triangle?
- Aka cystohepatic triangle;
- Medial border is common hepatic duct
- Inferior border is the cystic duct
- Superior border is the inferior surface of the liver
What is a common mechanism of injury to the facial nerve?
Always at risk during parotidectomy
What is a common mechanism of injury to the tail of the pancreas?
when ligating the splenic hilum
What is a common mechanism of injury to the testicular vessels?
During re-do open hernia surgery
What is a common mechanism of injury to the hepatic veins?
During liver mobilisation
What physiological/biochemical problem can cause arrhthymias following cardiac surgery?
Susceptibility to hypokalaemia (K+ <4.0 in cardiac patients)
What physiological/biochemical problem can cause neurosurgical electrolyte disturbance?
SIADH following cranial surgery causing hyponatraemia
What physiological/biochemical problem can cause ileus following gastrointestinal surgery?
Fluid sequestration and loss of electrolytes
What physiological/biochemical problem can cause pulmonary oedema following pneumonectomy?
Loss of lung volume makes these patients very sensitive to fluid overload
What physiological/biochemical problem can cause an anastomotic leak?
Generalised sepsis causing mediastinitis or peritonitis depending on site of leak
What physiological/biochemical problem can cause myocardial infarct?
May follow any type of surgery and in addition to cardiac effects, decreased cardiac output may well compromise grafts etc.
What are 5 good baseline investigations in the acutely unwell surgical patients?
- Blood tests: FBC, U+Es, CRP, serum calcium, LFTs, clotting
- ABG
- ECG (+ cardiac enzymes if MI suspected)
- CXR for collapse/ consolidation
- Urinalysis for UTI
What are 6 special tests that can be done for the acutely unwell surgical patient?
- CT scanning for identification of intra-abdominal abscesses, air and if luminal contrast is used an anastomotic leak
- Gatrograffin enema: for rectal anastomotic leaks
- Doppler USS of leg veins - DVT
- CTPA for PE
- Peritoneal fluid for U+E if ureteric injury suspected, or amylase if pancreatic injury suspected
- Echocardiogram if pericardial effusion suspected post-cardiac surgery and no pleural window made
What are the principles of management of surgical complications?
- safe and timely intervention
- stabilise, if operation needed in tandem with resuscitation - should be damage limitation type rather than definitive surgery (can be done in a stable patient next day)
Why is thrombolysis usually contraindicated in surgical patients?
Recent surgical is a contraindication
What may be preferable to use in some surgical patients to low molecular weight heparin, and weight?
IV heparin, as easier to reverse
What principles should laparotomies for bleeding follow?
Core principle of quadrant packing and then subsequent pack removal (rather than plunging large clamps into pools of blood - often worsens)
If packing controls bleeding, acceptable to leave packs in situ and return patient to ITU for pack removal the next day
What are the 2 ways to classify surgical wounds?
- Incisional or excisional
- Clean, clean-contaminated or dirty
What are the 4 key steps to wound healing?
- Haemostasis
- Inflammation
- Regeneration
- Remodelling
Over what time period does the haemostasis stage of wound healing occur?
Minutes to hours following injury
What does the haemostasis stage of wound healing involve?
Vasospasm in adjacent vessels, platelet plug formation and generation of fibrin rich clot
Over what time period does the inflammation stage of wound healing occur?
Days 1-5
What 4 key things does the inflammation stage of wound healing involve?
- Neutrophils migrate into wound (function impaired in diabetes)
- Growth factors released, including basic fibroblast growth factor (FGF) and vascular endothelial growth factor (VEGF)
- Fibroblasts replicate within the adjacent matrix and migrate into the wound
- Macrophages and fibroblasts couple matrix regeneration and clot distribution
Over what time period does the regeneration stage of wound healing occur?
Days 7-56
What 3 key things happen during the regeneration stage of wound healing?
- Platelet-derived growth factor and transformation growth factors stimulate fibroblasts and epithelial cells
- Fibroblasts produce a collagen network
- Angiogenesis occurs and wound resembles granulation tissue
Over what time period does the remodelling stage of wound healing occur?
6 weeks to 1 year, longest phase of healing process
What 3 key things happen during the remodelling stage of wound healing?
- Fibroblasts become differentiated (myofibroblasts) and these facilitate wound contraction
- Collagen fibres are remodelled
- Microvessels regress leaving a pale scar
What happens for neovascularisation to occur, an important early process in wound healing?
Endothelial cells may proliferate in the wound bed and recanalise to form a vessel
What are 3 diseases that can compromise microvascular flow and impair wound healing?
- Vascular disease
- Shock
- Sepsis
What is a condition that can impair fibroblast synthetic function and immunity in the wound healing process?
Jaundice
What are 2 types of problems with scars from surgical wounds?
- Hypertrophic scars
- Keloid scars
What are hypertrophic scars?
Excessive amounts of collagen within a scar; remains confined to boundaries of original wound
What are 2 features of hypertrophic scars?
- Nodules may be present histologically, containing randomly arranged fibrils wihtin and parallel fibres on the surface
- Tissue itself is confined to the extent of the wound itself
What is usually the cause of a hypertrophic scar?
Full thickness dermal injury
What may hypertrophic scars go on to develop?
Contractures
What are keloid scars?
Excessive amounts of collagen within a scar; will typically pass beyond boundaries of the original injury
What are 3 differences beween keloid and hypertrophic scars?
- Keloid scar passes beyond original boundaries while hypertrophic does not
- Keloid does not contain nodules, whereas hypertrophic does typically
- Hypertrophic prone to developing contracture
What can cause a keloid scar to form?
Even trivial injury
What are 4 classes of drugs which impair wound healing?
- Non-steroidal anti-inflammatory drugs
- Steroids
- Immunosuppressive agents
- Anti-neoplastic drugs
What is delayed primary closure of a wound?
Strategy of waiting to close a wound after around 48 hours, after it has proven not to have any signs of infection - aka closure by tertiary intention. Employed for clean-contaminated and clean wounds that are older than 6 hours
What is healing by primary intention?
- Healing of a clean wound without tissue loss; wound edges are brought together
- can be done with sutures, staple, adhesive or tape
- Simplest and fasted type of wound closure; involves re-epithelialisation only, for superficial wounds, and deeper wounds with well-approximated edges
What is secondary closure of a wound?
- Either spontaneous closure, or surgical closure after granulation tissue has formed.
- = healing a wound in which the edges cannot be approximated; requires a granulation tissue matrix to be built to fill the wound defect
- heals by granulation, contraction, and epithelialisation
