Post-operative care basics
Post-operative care is care given to patients after an operation in order to minimize post-operative complications. Early detection and treatment of post-operative complications is possible if there is optimal care. Some of the care is given to all post-operative patients, while the rest are specific to the type of operation. Routine cares include:
a. vital sign checking
b. Chest auscultation
c. Input and output monitoring
d. Checking for bladder and abdominal distention
e. Potent analgesics for pain relief
On subsequent post-operative days:
a. Oral intake can be started
b. Patients encouraged to ambulate
Certain essential equipment should be readily available in the recovery area:
● The trolley on which the patient is transported to the recovery area should have a mechanism for a rapid, easy head-down tilt.
● An oxygen supply and appropriate means of administering the gas (e.g. masks, nasal cannulae) must be available.
● Suction for maintaining a patent airway must be available.
Common complications management
The incidence of wound infection after surgical operations is related to the type of operation. The common classification of risk groups is as follows:
- Clean (e.g. hernia repair) – an uninfected operative wound without infl ammation and where no viscera are opened. Infection rate is 1% or less.
- Clean contaminated – where a viscus is open but with little or no spillage. Infection rate is less than 10%.
- Contaminated – where there is obvious spillage or obvious inflammatory disease, e.g. a gangrenous appendix. Infection rate is 15 – 20%. 4Dirty or infected – where there is gross contamination (e.g. a gunshot wound with devitalized tissue), or in the presence of frank pus or gross soiling (e.g. a perforated large bowel). Anticipated infection rate up to 40%.
In pre – antibiotic days, the haemolytic Streptococcus was feared most, but now, as this is still usually penicillin sensitive, the principal causes of wound infection are the penicillin resistant Staphylococcus aureus , together with Streptococcus faecalis , Pseudomonas , coliform bacilli and other bowel bacteria including Bacteroides . With continued use of antibiotics, more resistant strains of the organisms are appear-ing, such as the meticillin – resistant Staphylococcus aureus (MRSA) and the vancomycin – resistant Enterococcus (VRE).
Prophylactic antimicrobial chemotherapy (pro-phylactic antibiotics) was, in the early days of its use, believed to herald the end of wound infections. Unfortunately, the widespread and prolonged use of antimicrobials resulted in the emergence of resistant strains of bacteria, and side – effects such as diarrhoea and skin rashes.
Prophylaxis comprises scrupulous theatre and dressing technique, the isolation of infected cases and the elimination of carriers with colds or septic lesions among the medical and nursing staff.
Established infection is treated by drainage; antibiotics are given if there is, in addition, a spreading cellulitis. Open wounds may benefit from use of a negative pressure wound therapy device (vacuum – assisted closure (VAC) system), although direct application onto an open abdomen runs the risk of creating an enteric fistula.
Pain is an unpleasant sensation perceived by the patient in response to nociceptive stimuli. Untreated pain can lead to several problems that can be detrimental to the patient. Pain can cause sympathetic stimulation, which in turn may result in tachycardia, hypertension, sweating, anxiety, poor compliance with treatment and hypoventilation. Pain after abdominal surgery can lead to splinting of the diaphragm, resulting in hypoventilation, hypoxaemia and atelectasis of the lungs, and predispose to postoperative retention of pulmonary secretions and pneumonia (reduced ability to cough). Pain also causes the release of endogenous catecholamines, with cardiovascular sequelae.
For short procedures where postoperative pain is anticipated, particularly in the day surgery unit, analgesics such as paracetamol and diclofenac can be included as part of the premedication. They can be administered orally or rectally (after informed consent). This proves useful in the post-operative period by reducing the requirements for postoperative analgesia.
Postoperative efficiency of circulation depends on blood volume, cardiac function, neurovascular tone and adrenal secretions. Shock, or failure of the circulation, may follow:
- Excessive blood loss
- Escape of vascular fluid into the extra vascular compartments (“third spacing”)
- Marked peripheral vasodilatations
- Adrenocortical failure
- Pain or emotional stress
- Airway obstruction
- Arresting hemorrhage
- Restore fluid and electrolyte balance
- Correct cardiac dysfunction
- Establish adequate ventilation
- Maintain vital organ function and avert adrenal cortical failure
- Control pain and relief apprehension
- Blood transfusion if required.
Pulmonary collapse and infection
Some degree of pulmonary collapse occurs after almost every abdominal or transthoracic procedure. Mucus is retained in the bronchial tree, blocking the smaller bronchi; the alveolar air is then absorbed, with collapse of the supplied lung segments (usually the basal lobes). The collapsed lung continues to be perfused and acts as a shunt, which reduces oxygenation. The lung segment may become secondarily infected by inhaled or aspirated organisms, and, rarely, abscess formation may occur.
Pulmonary collapse occurs within the first post-operative 48 hours. The patient is dyspnoeic with a rapid pulse and elevated temperature. There may be cyanosis. The patient attempts to cough, but this is painful and, unless encouraged, he or she may fail to expectorate.
The sputum is at first frothy and clear, but later may become purulent, diagnostic of secondary infection. Examination reveals that the patient is distressed, with a typical painful ‘fruity cough’. This results from the sound of the bronchial secretions rattling within the chest and a good clinician should be able to make the diagnosis while still several yards away from the patient.
The chest movements are diminished, particularly on the affected side; there is basal dullness and air entry is depressed with the addition of coarse crackles. Pulse oximetry indicates a reduced saturation, and chest X – ray may reveal an opacity of the involved segment (usually basal or mid – zone), together with mediastinal shift to the affected side.
• Preoperatively, breathing exercises are given, smoking is forbidden and antibiotics prescribed if any chronic respiratory infection is present. Surgery should be postponed when possible until all pre – existing chest infection has resolved.
• Postoperatively, the patient is encouraged to cough, and breathing exercises are instituted, usually under the supervision of a physiotherapist. Small repeated doses of opiates diminish the pain of coughing but are insufficient to dull the cough reflex. Epidural anaesthesia and intercostal nerve blocks may help reduce the inhibitory pain of an abdominal or thoracic incision, without affecting the respiratory drive. Antibiotics are prescribed only if the sputum is infected; their selection is based on the sensitivity of the cultured organisms.
Deep vein thrombosis
In the operative and postoperative periods, the patient has an increased predisposition to venous thrombosis in the veins of the calf muscles, the main deep venous channels of the leg and pelvic veins. This predisposition has three main components (Virchow’s triad):
- Increased thrombotic tendency. Following blood loss and platelet consumption intraoperatively, more platelets are produced, numbers peaking around day 10. The new platelets have an increased tendency to aggregate. Fibrinogen levels also increase, predisposing to clot formation.
- Changes in blood flow. Increased stagnation within the veins occurs as a result of immobilization on the operating table and postoperatively in bed, and with depression of respiration.
- Damage to the vein wall prompts thrombus formation on the damaged endothelium. The damage may be due to an inflammatory process in the pelvis, or may be produced by pressure of the mattress against the calf or direct damage at operation (particularly the pelvic veins during pelvic procedures) or by disease (e.g. pelvic sepsis).
Deep vein thrombosis can be ‘silent’, but typically symptoms and signs occur during the second postoperative week, although they may come earlier or later. Studies using radioiodine – labelled fibrinogen, which is deposited as fibrin in the developing thrombus and which can be detected by scanning the leg, suggest that the thrombotic process usually commences during, or soon after, the operation. Earlier thrombosis may occur when a patient has already been immobile in hospital for some time preoperatively.
The patient complains of pain in the calf, and on examination there is tenderness of the calf and swelling of the foot, often with oedema, raised skin temperature and dilatation of the superficial veins of the leg. This is accompanied by a mild pyrexia. If the pelvic veins or the femoral vein are affected, there is massive swelling of the whole lower limb.
In the established case, anticoagulant therapy with an intravenous heparin infusion or subcutaneous low molecular weight heparin is commenced to prevent further propagation of the clot, and to increase fibrinolysis. Once anticoagulated, the patient can be mobilized with the lower limbs supported in elastic stockings to prevent oedema, and initial parenteral anticoagulation can be replaced by oral anticoagulation with warfarin.
The decision to anticoagulate a patient is particularly difficult if thrombosis occurs in the immediate postoperative period, as anticoagulation carries a serious risk of haemorrhage at the operation site. In this setting, a heparin infusion is usually used since the infusion can be immediately discontinued, and its effects reversed with protamine, if bleeding occurs.
If pulmonary embolism occurs in spite of anti-coagulation, or when anticoagulation is contraindicated, percutaneous insertion of an umbrella – like filter into the inferior vena cava may be indicated to prevent recurrent episodes of pulmonary embolization. Emboli get caught up in the umbrella rather than in the pulmonary arteries.
Postoperative ﬂuid balance is important in order to maintain circulating intravascular volume, isotonicity and adequate oxygen-carrying capacity. Fluid balance involves giving enough ﬂuids and giving ﬂuids appropriately based on the individual patient’s needs.
Total ﬂuid loss in the average adult is about 2500 mL/day. This includes 100–200 mL/day through the gastrointestinal tract, insensible ﬂuid losses (through the lungs and skin) of about 500–1000 mL/day, and urine output of about 1000 mL/day. The ﬂuid volume required, therefore, is generally about 2500 mL/day for a 70-kg adult, with Na+ of 30 mEq/L and K+ of 15–20 mEq/L.
The ﬂuids available are crystalloids, colloids, blood and blood products. Generally crystalloids containing electrolytes normally found in plasma are administered. Depending on the degree of blood loss (estimated and measured), blood and/or blood products might be required. Table 3.2 lists the types of ﬂuids commonly used, and Figure 3.6 shows the volumes of distribution of isotonic colloid, saline and glucose solutions.
As a general rule, maintenance requirements to compensate for preoperative starvation and insensible loss amount to about 2 mL/kg/h. In addition to maintenance requirements and measured loss, note the following:
● For most major surgical procedures, an additional 4 mL/kg/h should be added, giving a total of 6 mL/kg/h.
● For major abdominal procedures and trauma, an additional 6 mL/kg/h should be added, giving a total of 8 mL/kg/h.
● For major thoracic and complex procedures, 8 mL/kg/h is added to the maintenance regime, giving a total of 10 mL/kg/h.