Introduction

Over a half century ago, at the beginning of the modern cardiac surgery era, routine overnight ventilation was one of the essential components of postoperative care (₁). Nowadays, low dose, short acting anesthetic agents which replaced the former high dose opioid regimens offer a faster postoperative recovery and decreased the need for mechanical ventilatory support (₂,₃). This methodological improvement has resulted in a new concept: Fast track (₄)!

The fast track concept includes early postoperative extubation and shorter length of stay in the intensive care unit (ICU) and hospital (₅). Cumulative results of this management are improved comfort of the patient and decreased costs of the hospitalization. Anesthetic maneuvers are main components of fast track with the help of various surgical techniques facilitating faster recovery and extubation in the operating room. The target is better utilization of the medical, social and financial resources without adversely affecting the mortality and morbidity of the patient (₆).

This goal may be achieved by using short acting anesthetic drugs and a team work of the surgeon in collaboration with nursing and ICU stuff. Standardized clinical pathways in patient care have to be applied and technical improvements in surgical methods may reduce total duration of the operation (i.e. the aortic cross clamping and cardiopulmonary bypass times) (₇,₈,₉,₁₀,₁₁,₁₂).

Patients & Method

Thirty six cases (18 males and 18 females) with non-complex congenital cardiac anomales were operated in our clinic with open heart technique between may 2002 and June 2004. Thirteen of them with an atrial septal defect and twenty three with perimembraneous ventricular septal defects. Their ages ranged between 12 and 204 months and weighed between 8,6 and 56 kg. Table 1 shows clinical and demographic data of the patient group. Sixteen cases in this cohort were extubated in the operating room or in the ICU before the 6th postoperative hour. Parameters of patients, who were earlier extubated, were compared with those who were extubated later. The demographic data are collected in table 1.

Figure 1

Table 1: Fast track group (ASD: Atrial septal defect; VSD: Ventricular septal defect; EA: Ebstein's anomaly)

Figure 2

Table 2: Postoperative results

Anesthetic management

Surgical technique

CPB technique

Postoperative care

Results

Mean intensive care unit (ICU) length of stay (LOS) was 2 to 12 hours and the hospital LOS ranged between 3 to 4 days.

There were neither major nor minor complications and mortality during the hospital stay and all patients are in well condition on their follow-up period (3 to 41 months).

Discussion

Principles of fast track in pediatric cases were described as minimally invasive surgical techniques, reduction of the CPB prime volume, mild hypothermic bypass, and early removal of endotracheal tube and catheters to prevent the infection risk (₂₇). Supplementation with hypnotic drugs allows reduction of the opioid dose and enabling earlier extubation without compromising hemodynamic stability (₂₈, ₂₉). Low-dose narcotics combined with short-acting anesthetic and sedative agents, facilitate early tracheal extubation after cardiac surgery (₃₀).

Fast-track cardiac surgery is partly dependent on smaller-dose opioid regimens and although these may be associated with increased hemodynamic responses during surgery, there does not appear to be an increased risk of complications (₈, ₃₁).

Preestablished criteria are modified from the criterias for early tracheal extubation of the patiens undergoing coronary artery bypass graft surgery: Patient awake, responsive and cooperative, negative inspiratory force >-20, vital capacity >10 ml/kg, with a spontaneous respiratory rate between 20-30 breaths/min and satisfactory arterial blood gas tensions (PaO₂ >80 on FiO₂ less or equal to 50%), body temperature >36.5 C°, pH >7.3, drainage <10-15 ml/h for 2 h absence of uncontrolled dysrhythmia and hemodynamically stable (₈).

There are several potential indications for maintaining a moderate to deep level of neuromuscular blockade during cardiac surgery. Neuromuscular blocking drugs will reduce muscle rigidity associated with opioids, prevent shivering during hypothermia, limit oxygen consumption, and reduce muscle contractions during defibrillations. In addition, the possibility of patient or diaphragmatic movement during light stages of anesthesia can be reduced if paralysis is maintained (₁₉). Recent clinical trials have demonstrated that prolonged postoperative paralysis can occur following cardiopulmonary bypass, and that residual neuromuscular block can impair clinical recovery of the fast-track cardiac patient (₂₀,₂₁).

Very early extubation of children after cardiac surgery has been suggested as a safe alternative to prolonged postoperative intubation but is still not common practice. Studies of early extubation in children may not have described reasons for failure to extubate, or have included non-bypass or only low-risk repairs (₂₂). Successful early extubation of even young children is possible and easily accomplished in most children undergoing cardiopulmonary bypass, even with complex procedures, but advantages of extubation in the operating room vs. immediate ICU extubation remain unclear. Transient mild-to-moderate mixed acidosis is common and requires no treatment. Full implementation requires acceptance by surgical and ICU staffs (₂₂).

The use of more expensive but shorter-acting anesthetics may be justified if they permit faster extubation and shorter ICU and hospital stays and these shorter stays translate into lower total costs. However, Engoren et al found that the use of the shorter-acting opioids, sufentanil and remifentanil, was not associated with shorter ventilator times, ICU stays, or hospital stays. Fentanyl, sufentanil, and remifentanil all produced similar outcomes with similar direct variable costs. Prompt extubation has been touted as the first step in fast-track cardiac surgery. They have concluded that more expensive but shorter-acting opioids (sufentanil and remifentanil) produced equally rapid extubation, similar stays and costs to fentanyl (₂₃).

In order to achieve early tracheal extubation, the anesthetic management in children with noncomplex congenital malformations must be tailored away from the usual high-dose narcotic regimens. After a relatively light premedication, low doses of fentanyl (5-15 µg/kg) are supplemented with an infusion of propofol, the generous use of inhalation anesthetics, and neuromuscular blocking agents (₅,₉,₂₄). This balanced anesthetic technique has been shown to suppress the perioperative stress response as effectively as a high-dose narcotic technique does (₉).

Titration of these drugs and reversal of neuromuscular blockade permit the return of spontaneous ventilatory efforts soon after the conclusion of surgery. Several potential problems may be encountered after early extubation is accomplished. Respiratory acidosis is frequently seen in these children on admission to the ICU (₂₅).

Residual effects of anesthetic agents contribute to both central and obstructive etiologies of this hypoventilation. The placement of an oral airway prior to extubation helps to overcome the obstructive component and improve ventilation. These patients also exhibit an increased frequency of vomiting in the ICU (₂₅). Since this distressing problem is distasteful to the child and may increase the reluctance of the medical staff to transfer the child out of the ICU, the prophylactic administration of an antiemetic prior to extubation is quite helpful. Finally, since lower doses of narcotics are used intraoperatively, a plan for postoperative pain management must be devised and implemented as soon as any respiratory acidosis is resolved. Older children can be instructed preoperatively on the use of a patient-controlled analgesia (PCA) device to deliver narcotics after surgery. In order to avoid some of the adverse effects of large doses of intravenous narcotics, regional anesthetic techniques have been used effectively to supplement general anesthesia in the OR and help control pain postoperatively in children undergoing non-cardiac surgery. Its use in children undergoing cardiac surgery is now receiving a significant amount of scrutiny.

Every patient could be a candidate for early extubation (₇). Intraoperative and postoperative morbidity rates can determine the feasibility of a fast track protocol in any individual case. One must keep in mind the nature of the cardiac pathology requiring surgical correction, intraoperative risk variables and postoperative risk of complications. As described in many recent papers, fast track is a safe procedure in selected patients (₂₆,₂₇,₂₈,₂₉,₃₀,₃₁). There is no increase in postoperative cardiorespiratory risks, symphatoadrenal stress, morbidity and mortality (₉).

Nausea and vomiting are frequent problems in early extubated cases where their incidence may reach up to 30%. Prophylactic antiemetic agents must be included in the anesthesia protocol. Another issue is controlling of the arterial blood pressure and strict management of pain is mandatory.

Another important issue is the financial aspect of the surgery. Fast track protocols offer shorter length of stay both in the ICU and in the hospital, which directly reduces total costs for a patient. It's important to monitor not only the hospital phase but also the pre- and post-hospital care of the patient for cost-effectiveness (₈).

Conclusion

In conclusion, fast track protocols offer the opportunity of earlier extubation of the patients with non-complex cardiac anomalies and may result in spending fewer hours in the ICU. The hospital stay also decreases and patients can be discharged earlier in many cases, which also has a positive effect on hospital costs. A very early extubation protocol can be safely applied in many cases. But the cost-effectiveness of a protocol cannot be explained with only focusing on the hospital period. The pre- and posthospital periods of the patients are directly affected by the method of surgery and anesthesia. Good provision of pain is very mandatory for early mobilization of the patients and shorter duration of ICU and hospital LOSs reduce the working load of the nursing staff.

Correspondence to

Dr. Kivanç METİN 1402 Sok No:2/2 Alsancak Izmir Phone: +90 532 2966938 Facsimile: +90 232 4642470 e-mail:kmetin@yahoo.com