Esophageal Doppler (ODM II) improves intraoperative hemodynamic monitoring during laparoscopic surgery

Anaesthesia for laparoscopic surgery

Laparoscopic surgery has become increasingly common with reduced postoperative pain and faster recovery. Clinicians managing patients undergoing abdominal laparoscopic surgery should appreciate the physiological changes which mainly arise from patient positioning and the effects of pneumoperitoneum.

Bilateral otorrhagia: a rare complication of laparoscopic abdominopelvic surgery

An 80-year-old woman without any previous otological symptoms underwent laparoscopic abdominoperineal resection for T3N0M0 low rectal carcinoma 4-5 cm from the anal verge. The total operative time was 6 h, of which she spent long hours in the Trendelenburg (35°) position due to difficult pelvic dissection. Midway through the procedure, she developed spontaneous non-traumatic bilateral otorrhagia. This case highlights the potential risk of increased intracranial pressure during prolonged periods of being in a steep Trendelenburg position caused either by the position itself or in combination with carbon dioxide pneumoperitoneum. We also consider the effect of a sudden change from this position to supine as a potential risk.

Advancing frontiers in anaesthesiology with laparoscopy

The introduction of laparoscopy in the surgeon's armamentarium was in fact a "revolution in the history of surgery". Since this technique involves insufflation of carbon dioxide it produces several pathophysiological changes which have to be understood by the anaesthesiologist who can modify the anaesthesia technique accordingly. Advantages of laparoscopy include reduced pain, small scars and early return to work. Certain complications specific to laparoscopic surgery are due to carboperitoneum and increased intra-abdominal pressure. Venous air embolism, although very rare, can be lethal if not managed promptly. Other complications include subcutaneous emphysema, haemodynamic compromise and arrhythmias. Although associated with minimal postoperative morbidity, postoperative pain, nausea and vomiting can be quite problematic. The limitations of laparoscopy have been overcome by the introduction of robotic surgery. There are important implications for the anaesthesiologist during robotic surgeries which have to be practiced accordingly. Robotic surgery has a learning curve for both the surgeon and the anaesthesiologist. The robot is bulky, and cannot be disengaged after docking. Therefore it is important that the anaesthetized patient remains immobile throughout surgery and anaesthesia is reversed only after the robot has been disengaged at the end of surgery. Advances in laparoscopy and robotic surgery have modified anaesthetic techniques too.

Hemodynamic changes during robotic radical prostatectomy

BACKGROUND

Effect on hemodynamic changes and experience of robot-assisted laparoscopic radical prostatectomy (RALRP) in steep Trendelenburg position (45°) with high-pressure CO(2) pneumoperitoneum is very limited. Therefore, we planned this prospective clinical trial to study the effect of steep Tredelenburg position with high-pressure CO(2) pneumoperitoneum on hemodynamic parameters in a patient undergoing RALRP using FloTrac/Vigileo™1.10.

METHODS

After ethical approval and informed consent, 15 patients scheduled for RALRP were included in the study. In the operation room, after attaching standard monitors, the radial artery was cannulated. Anesthesia was induced with fentanyl (2 μg/kg) and thiopentone (4-7 mg/kg), and tracheal intubation was facilitated by vecuronium bromide (0.1 mg/kg). The patient's right internal jugular vein was cannulated and the Pre Sep™ central venous oximetry catheter was connected to it. Anesthesia was maintained with isoflurane in oxygen and nitrous oxide and intermittent boluses of vecuronium. Intermittent positive-pressure ventilation was provided to maintain normocapnea. After CO(2) pneumoperitoneum, position of the patient was gradually changed to 45° Trendelenburg over 5 min. The robot was then docked and the robot-assisted surgery started. Intraoperative monitoring included central venous pressure (CVP), stroke volume (SV), stroke volume variation (SVV), cardiac output (CO), cardiac index (CI) and central venous oxygen saturation (ScvO(2)).

RESULTS

After induction of anesthesia, heart rate (HR), SV, CO and CI were decreased significantly from the baseline value (P>0.05). SV, CO and CI further decreased significantly after creating pneumoperitoneum (P>0.05). At the 45° Trendelenburg position, HR, SV, CO and CI were significantly decreased compared with baseline. Thereafter, CO and CI were persistently low throughout the 45° Trendelenburg position (P=0.001). HR at 20 min and 1 h, SV and mean arterial blood pressure after 2 h decreased significantly from the baseline value (P>0.05) during the 45° Trendelenburg position. CVP increased significantly after creating pneumoperitoneum and at the 45° Trendelenburg position (after 5 and 20 min) compared with the baseline postinduction value (P>0.05). All these parameters returned to baseline after deflation of CO(2) pneumoperitoneum in the supine position. There were no significant changes in SVV and ScvO(2) throughout the study period.

CONCLUSIONS

The steep Trendelenburg position and CO(2) pneumoperitoneum, during RALRP, leads to significant decrease in stroke volume and cardiac output.

Intra-operative oxygen delivery in infusion volume-optimized patients undergoing laparoscopic colorectal surgery within an enhanced recovery programme: the effect of different analgesic modalities

AIM

Patients undergoing major open surgery who have an indexed oxygen delivery (DO(2) I) > 600 ml/min/m(2) have been shown to have a lower incidence of morbidity and mortality compared with those whose DO(2) I is below this level. Laparoscopy and Trendelenburg positioning cause a reduction in DO(2) I. We aimed to quantify the effect of the type of analgesia on DO(2) I and to correlate the DO(2) I achieved with the incidence of anastomotic leakage in patients undergoing laparoscopic surgery.

METHOD

Following ethical approval, patients were randomized to receive spinal anaesthesia (Group S), epidural analgesia (Group E) or intravenous morphine (Group P) followed by postoperative patient-controlled analgesia (PCA). In addition to standard monitoring, oesophageal Doppler monitoring of the stroke volume allowed directed intravenous fluid therapy. The mean DO(2) I was compared with the anastomotic leakage rate.

RESULTS

Seventy-five patients were recruited (Group S, 27; Group E, 23; Group P, 25). The mean (range) DO(2) I for all patients was 490 (230-750) ml/min/m(2) . The analgesic modality had no effect on DO(2) I. Of the 18 patients with a DO(2) I of < 400 ml/min/m(2) , four (22%) developed anastomotic leakage compared with one (%) of the 57 patients with a DO(2) I of > 400 ml/min/m(2) (P = 0.01).

CONCLUSION

The analgesic modality used had no effect on the DO(2) I achieved. Anastomotic leakage was significantly higher in patients with a DO(2) I of < 400 ml/min/m(2) . A further study assessing the outcome after raising the DO(2) I with inotropes is required.

Cardiac function during steep Trendelenburg position and CO2 pneumoperitoneum for robotic-assisted prostatectomy: a trans-oesophageal Doppler probe study

BACKGROUND

Haemodynamic changes associated with pneumoperitoneum and steep Trendelenburg position were investigated in non-obese, ASA I-II males, using general anaesthesia (sevoflurane in air/O2, 40%) undergoing robotic-assisted laparoscopic prostatectomy.

METHODS

A trans-oesophageal echo-Doppler probe (Arrow International) measured cardiovascular changes in heart rate (HR), mean arterial pressure (MAP), cardiac output (CO), systemic vascular resistance (SVR), stroke volume (SV) and aortic diameter (AoD) in 35 of 37 males. Assessments were conducted after induction of general anaesthesia in: the supine position; at 45 degrees Trendelenburg; Trendelenburg + pnuemoperitoneum (intra-abdominal 15 mmHg); and at the end of surgery in the supine position.

RESULTS

The Trendelenburg position increased stroke volume. Trendelenburg position + pneumoperitoneum increased MAP and SVR and decreased AoD.

CONCLUSIONS

Pneumoperitoneum and steep Trendelenburg position significantly increase MAP and SVR. Trendelenburg position increased stroke volume. Pneumoperitoneum decreases aortic diameter. No significant changes in cardiac output or stroke volume were noted.

Validation of esophageal Doppler for noninvasive hemodynamic monitoring under pneumoperitoneum

BACKGROUND

Commonly used perioperative measurements of hemodynamics, such as Swan-Ganz catheter assessment, are invasive and may not be reliable under pneumoperitoneum. The purpose of this study was to validate the use of esophageal Doppler for noninvasive hemodynamic monitoring under pneumoperitoneum in an experimental pig model.

METHODS

Eight female pigs were submitted to two 30-min study periods, one each for the baseline (no interventions) and pneumoperitoneum (12-mmHg carbon dioxide pneumoperitoneum) conditions. One pig was excluded because of tachycardia (>140 at baseline). A Swan-Ganz pulmonary artery catheter was used to measure cardiac output (CO-SG) and pulmonary capillary wedge pressure (PCWP). An esophageal Doppler probe was inserted to record cardiac output (CO-ED) and corrected flow time (FTc), an index of preload. Transthoracic echocardiography was used to measure left ventricular end-diastolic diameter (LVEDD) and cardiac output (CO-TTE). Pearson correlation was used to assess individual associations between the measured hemodynamic parameters.

RESULTS

There was good correlation between CO-ED and CO-SG (r = 0.577; p < 0.001) and excellent correlation between CO-ED and CO-TTE (r = 0.815; p < 0.001). There was no correlation between FTc and LVEDD or PCWP. These relationships were consistent when analyzed separately at baseline and during pneumoperitoneum.

CONCLUSION

Esophageal Doppler monitoring is a valid noninvasive method of estimating cardiac output at baseline and during pneumoperitoneum in a porcine model. Corrected flow time did not correlate with other estimates of preload at baseline or during pneumoperitoneum.