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Autonomic Nervous System Modulation During Laparoscopic Prostatectomy

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT01927380
Recruitment Status : Completed
First Posted : August 22, 2013
Last Update Posted : November 5, 2014
Information provided by (Responsible Party):
Riccardo Colombo, ASST Fatebenefratelli Sacco

Brief Summary:
The purpose of this study is to measure the variations of autonomic nervous system (ANS) modulation directed to the heart and vessels induced by pneumoperitoneum and steep trendelenburg position.

Condition or disease Intervention/treatment
Intervention Affecting Autonomic Nervous System Other: steep trendelenburg position with pneumoperitoneum

Detailed Description:

The association of pneumoperitoneum and steep trendelenburg position, commonly used during laparoscopic radical prostatectomy, leads to significant changes in hemodynamics. Many studies found modifications of cardiac output, stroke work index, arterial pressure, central vein pressure and wedge pressure. Moreover, there are reports of severe bradycardia and cardiac arrest following pneumoperitoneum in association with steep trendelenburg. A vagal hypertone (induced by the combination of these two factors) or sympathetic hypractivity (elicited by pneumoperitoneum) had been alternatively postulated to cause these hemodynamic changes. To date there are not sufficient physiologic evidences of modification of ANS activity during steep trendelenburg position in association with pneumoperitoneum.

ANS modulation is studied non invasively by means of heart rate variability and baroreflex sensitivity. Beat-to-beat intervals are computed detecting the QRS complex on the ECG and locating the R-apex using parabolic interpolation. The maximum arterial pressure within each R-to-R interval is taken as systolic arterial pressure (SAP). Sequences of 300 values are randomly selected inside each experimental condition. The power spectrum is estimated according to a univariate parametric approach fitting the series to an autoregressive model. Autoregressive spectral density is factorized into components each of them characterized by a central frequency. A spectral component is labeled as LF if its central frequency is between 0.04 and 0.15 Hz, while it is classified as HF if its central frequency is between 0.15 and 0.4 Hz. The HF power of R-to-R series is utilized as a marker of vagal modulation directed to the heart , while the LF power of SAP series is utilized as a marker of sympathetic modulation directed to vessels. The ratio of the LF power to the HF power assessed from R-to-R series is taken as an indicator simpatho-vagal balance directed to the heart. Baroreflex control in the low frequencies is computed as the square root of the ratio of LF(RR) to LF(SAP). Similarly baroreflex control in the high frequencies is defined as the square root of the ratio of HF(RR) to HF(SAP).

The optic nerve sheet's diameter is assessed echographically after induction of general anesthesia and at the end of the surgery.

Management of general anesthesia is standardized:

  • induction with propofol 1.5-2 mg/kg, Remifentanil Target Controlled Infusion (TCI) Ce 4 ng/ml , neuromuscolar blockade with cisatracurium 0.2 mg/kg.
  • Maintenance: Sevoflurane 0.6-1.5 MAC (State Entropy target: 40-60); Remifentanil TCI (range Ce 3-15 ng/ml) (Surgical Pleth Index target: 20-50).
  • mechanical ventilation at respiratory rate ≥14 breats/min, with tidal volume adjusted to maintain end-tidal carbon dioxide at 32-38 mmHg, and Pplateu <32 cmH2O.

Sample size:

to detect a difference in LF/HF ratio of 0.8 with a SD of 1.7, a power of 0.80 and type I error of 0.05, 37 patients are needed.

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Study Type : Observational
Actual Enrollment : 37 participants
Observational Model: Cohort
Time Perspective: Prospective
Study Start Date : August 2013
Actual Primary Completion Date : March 2014
Actual Study Completion Date : March 2014

Group/Cohort Intervention/treatment
males undergoing elective laparoscopic radical prostatectomy steep trendelenburg position with pneumoperitoneum
Other: steep trendelenburg position with pneumoperitoneum
ANS activity and baroreflex modulation is assessed at (i) baseline; (ii) after induction of general anesthesia; (iii) after steep trendelenburg position (head down at 25 degrees); (iv) after induction of pneumoperitoneum and (v) after removal of trendelenburg and pneumoperitoneum

Primary Outcome Measures :
  1. To measure the changes of ANS modulation directed to the heart and to the vessels, and the changes of baroreflex control induced by steep trendelenburg position and pneumoperitoneum [ Time Frame: Day of surgery ]

Secondary Outcome Measures :
  1. To measure the correlation between ANS changes and hemodynamics [ Time Frame: day of surgery ]

Other Outcome Measures:
  1. to measure changes of the optic nerve sheet's diameter during steep trendelenburg and pneumoperitoneum [ Time Frame: day of surgery ]

Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years to 70 Years   (Adult, Older Adult)
Sexes Eligible for Study:   Male
Accepts Healthy Volunteers:   Yes
Sampling Method:   Non-Probability Sample
Study Population
Human males undergoing elective laparoscopic prostatectomy

Inclusion Criteria:

  • males scheduled for elective laparoscopic prostatectomy
  • sinus rhythm at ECG
  • ectopic heart beats <5% of all heart beats
  • american society of anesthesiologists status 1-3

Exclusion Criteria:

  • autonomic dysfunction (documented or suspected)
  • adrenal or thyroid dysfunction
  • organ dysfunction secondary to diabetes (i.e. nephropathy, retinopathy, neuropathy)
  • history of stroke, traumatic spinal injury, heart surgery or major vascular surgery
  • intracranial hypertension (documented or suspected)
  • hydrocephalus
  • cardiac functional status ≥NYHA IIb
  • non sinusal heart rhythm
  • ectopic heart beats ≥5% of normal heart beats
  • therapy with beta-blockers or beta2-agonists

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT01927380

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Azienda Ospedaliera "Luigi Sacco" - Polo Universitario - University of Milan
Milan, Italy, 20157
Sponsors and Collaborators
ASST Fatebenefratelli Sacco
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Study Chair: Ferdinando Raimondi, Director Azienda Ospedaliera "L.Sacco"
Principal Investigator: Riccardo Colombo, Consultant Azienda Ospedaliera "L.Sacco"
Study Director: Stefano Guzzetti, Director Azienda Ospedaliera "L.Sacco"

Publications automatically indexed to this study by Identifier (NCT Number):
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Responsible Party: Riccardo Colombo, MD, ASST Fatebenefratelli Sacco Identifier: NCT01927380    
Other Study ID Numbers: CE#371/2013
First Posted: August 22, 2013    Key Record Dates
Last Update Posted: November 5, 2014
Last Verified: November 2014
Keywords provided by Riccardo Colombo, ASST Fatebenefratelli Sacco:
autonomic nervous system modulation
heart rate variability
steep trendelenburg