Robotic Cardiac Surgery Part II: Anesthetic Considerations for Robotic Coronary Artery Bypass Grafting

Intrathecal Morphine for Analgesia in Minimally Invasive Cardiac Surgery: A Randomized, Placebo-controlled, Double-blinded Clinical Trial

BACKGROUND

Intrathecal morphine decreases postoperative pain in standard cardiac surgery. Its safety and effectiveness have not been adequately evaluated in minimally invasive cardiac surgery. The authors hypothesized that intrathecal morphine would decrease postoperative morphine consumption after minimally invasive cardiac surgery.

METHODS

In this randomized, placebo-controlled, double-blinded clinical trial, patients undergoing robotic totally endoscopic coronary artery bypass received either intrathecal morphine (5 mcg/kg) or intrathecal saline before surgery. The primary outcome was postoperative morphine equivalent consumption in the first 24 h after surgery; secondary outcomes included pain scores, side effects, and patient satisfaction. Pain was assessed via visual analog scale at 1, 2, 6, 12, 24, and 48 h after intensive care unit arrival. Opioid-related side effects (nausea/vomiting, pruritus, urinary retention, respiratory depression) were assessed daily. Patient satisfaction was evaluated with the Revised American Pain Society Outcome Questionnaire.

RESULTS

Seventy-nine patients were randomized to receive intrathecal morphine (n = 37) or intrathecal placebo (n = 42), with 70 analyzed (morphine 33, placebo 37). Intrathecal morphine patients required significantly less median (25th to 75th percentile) morphine equivalents compared to placebo during first postoperative 24 h (28 [16 to 46] mg vs. 59 [41 to 79] mg; difference, -28 [95% CI, -40 to -18]; P < 0.001) and second postoperative 24 h (0 [0 to 2] mg vs. 5 [0 to 6] mg; difference, -3.3 [95% CI, -5 to 0]; P < 0.001), exhibited significantly lower visual analog scale pain scores at rest and cough at all postoperative timepoints (overall treatment effect, -4.1 [95% CI, -4.9 to -3.3] and -4.7 [95% CI, -5.5 to -3.9], respectively; P < 0.001), and percent time in severe pain (10 [0 to 40] vs. 40 [20 to 70]; P = 0.003) during the postoperative period. Mild nausea was more common in the intrathecal morphine group (36% vs. 8%; P = 0.004).

CONCLUSIONS

When given before induction of anesthesia for totally endoscopic coronary artery bypass, intrathecal morphine decreases use of postoperative opioids and produces significant postoperative analgesia for 48 h.

EDITOR’S PERSPECTIVE

A career in cardiac anaesthesia in India: The heart of the matter

Cardiac anaesthesia is a demanding, but fulfilling speciality which challenges the skills, knowledge, professional and personal competence of cardiac anaesthesiologists on a daily basis. This article outlines the brief history of the subspecialty of cardiac anaesthesia in India, its growth and progress over the decades, reasons for choosing it as a career option, variations in practice standards and how the speciality has been affected by the coronavirus 2019 pan?demic.

Does Intolerance of Single-Lung Ventilation Preclude Robotic Off-Pump Totally Endoscopic Coronary Bypass Surgery?

Objective

Robotic off-pump totally endoscopic coronary artery bypass (TECAB) usually requires isolated single (right) lung ventilation to adequately expose the surgical site. However, in some patients, persistent oxygen desaturation may occur and conversion to cardiopulmonary bypass (CPB) or sternotomy may be necessary. We reviewed the characteristics and clinical outcomes in patients who did not tolerate single-lung ventilation during TECAB surgery.

Methods

After Institutional Review Board approval we reviewed 440 patients undergoing robotic TECAB at our institution between July 2013 and April 2019. Patients were separated into 2 groups based on their ability to tolerate single-lung ventilation during the procedure. Group 1 included patients able to tolerate single-lung ventilation and Group 2 were patients who required double-lung ventilation to tolerate the procedure. Early and mid-term outcomes were compared.

Results

Group 2 (121 patients) had higher Society of Thoracic Surgeons scores, higher body mass index, and more triple-vessel disease than Group 1 (319 patients). Group 2 had more bilateral internal mammary artery use, multivessel grafting, and longer operative times. One patient underwent conversion to sternotomy and 5 required CPB (all in Group 1). Intensive care unit and hospital length of stay were longer in Group 2. Observed/expected mortality did not differ between groups (1.06% in Group 2 vs 0.4% in Group 1; P = 0.215). At mid-term follow-up, cardiac-related/overall mortality and freedom from major adverse cardiac events were similar.

Conclusions

In our cohort, intolerance of single-lung ventilation did not preclude robotic off-pump TECAB. Double-lung ventilation is feasible during the procedure and may prevent conversions to sternotomy or use of CPB, resulting in excellent early and mid-term outcomes.