Chapter 7 – Routine Early Postoperative Care

Abstract

Early postoperative care is a critical factor in determining successful outcomes following cardiac surgery. With increasing pressure for efficiency while ensuring patient safety is maintained, it is vital that healthcare professionals are familiar with the pathways and protocols designed to allow for rapid recovery of patients. At the same time it is important that complications are detected early, escalated appropriately and intervened upon in a timely fashion.

Chapter 7 Routine Early Postoperative Care

Barbora Parizkova and Aravinda Page

Fast-Tracking

Determining if a patient is suitable to be fast-tracked or for enhanced recovery versus the need for more advanced care begins early in the patient pathway, during the preoperative assessment by the surgeon and anaesthetist. ‘Routine’ cardiac cases are ‘fast-tracked’ in a cardiac recovery unit, which is a part of the ICU. Such clinical areas are often managed by experienced nursing staff who follow institution-specific protocols while being overseen by a responsible physician. These protocols address issues such as the weaning from mechanical ventilation and the management of expected postoperative issues. These strategies have been safely implemented to facilitate early ICU and hospital discharge. It is important to emphasize the need for early involvement of specialized medical staff when there is deviation of a patient’s progress from a clearly defined pathway or anticipation of such an incident.

Transfer, ICU Admission and Handover

During the transfer from the operating room, uninterrupted invasive monitoring is essential for the early recognition of haemodynamic instability secondary to fluid shifts during movement and dysrhythmias. On arrival in the ICU it is important that there is a prompt handover to the nurse responsible for ongoing care. This should include anaesthetic and intraoperative details as shown in Box 7.1. This is usually performed while the ICU ventilator is being connected and monitoring (usually including capnography, invasive monitoring, oximetry and ECG) is switched from the portable monitor to the fixed ICU monitor . In patients who require epicardial pacing, it is important that the pacing is checked and changed from a fixed rate to demand mode as appropriate. Once the handover has been completed, an initial ABG should be drawn to ensure appropriate oxygenation and ventilation is being achieved. Baseline potassium, Hb and metabolic state should be reviewed and corrected as appropriate. If the patient is bleeding excessively, a baseline full blood count and coagulation screen and/or a thromboelastogram (TEG) should be acquired .

Box 7.1 Handover checklist

The patient
- Demographics: name, age, height, weight
- Pre-existing medical conditions
- List of preoperative medications
- Allergies/drug sensitivities
- Cardiac status (ventricular dysfunction, valvular disease)
The procedure
- Planned/actual surgical procedure performed
- Complications and other significant events
- Details regarding weaning from CPB, vasoactive drugs, pacing, IABP
- Optimal cardiac filling pressures in theatre
Anaesthesia
- Vascular line types and insertion sites (along with any complications that occurred during their placement)
- Laryngoscopy grade, difficulties during intubation
- Continuous infusions and current rates
- Recent ABG (especially potassium and Hb levels)
- Blood products administered and ordered for later administration
- Fluids administered, urine output and use of haemofiltration during CPB
- Recent laboratory investigations (TEG, full blood count, coagulation)
The postoperative plan
- Optimal acceptable ranges of MAP, CVP, PAWP as ICU targets
- Expected duration of sedation and mechanical ventilation
- Need for CXR as indicated

Mechanical Ventilation, Sedation and Analgesia

In the UK, it is widely considered that the risk of bleeding, haemodynamic instability and hypothermia following cardiac surgery outweighs any potential benefits of tracheal extubation in the operating theatre prior to transfer to ICU. Initially, a ‘full’ mechanical ventilation mode is selected, for example synchronized intermittent mandatory ventilation (SIMV) with an adequate rate (10–12 breaths per minute), tidal volume (6–8 ml kg⁻¹) and a modest PEEP (5 cmH₂O) to reduce postoperative atelectasis. As spontaneous respiratory effort returns, lower-rate SIMV with pressure-support ventilation (PSV) can be used. Eventually, ventilation using only PSV (to overcome the resistance of the ventilatory system) with a modest PEEP can be used prior to tracheal extubation.

In the setting of mediastinal bleeding, a higher PEEP (5–10 cmH₂O) may be used; however, this may have deleterious haemodynamic effects. Sedation and mechanical ventilation are usually continued for 30–240 minutes post transfer to the ICU to allow for rewarming and to exclude significant bleeding . Use of forced-air warming blankets can minimize the duration of postoperative hypothermia (<36 °C), which is not uncommon and can have adverse effects (Box 7.2). Many centres routinely use propofol for sedation due to its short and predictable duration of action. The criteria that should be considered prior to switching of sedation with a view to weaning ventilation and extubation are listed in Box 7.3.

Box 7.2 Adverse effects of hypothermia

Increased SVR and hypertension
Predispose to atrial and ventricular arrhythmias
Precipitate shivering, which increases peripheral O₂ consumption and CO₂ production
Produce platelet dysfunction and generalized impairment of the coagulation cascade
Prolongs the time to tracheal extubation