The Effects of Hyperventilation Prior to CO2 Insufflation During Laparoscopic Cholecystectomy

• ClinicalTrials.gov Identifier: NCT01182545
• Recruitment Status: Completed
• First Posted: August 17, 2010
• Last Update Posted: November 19, 2010
• Sponsor: King Faisal University
• Information provided by: King Faisal University

Study Description

Brief Summary:

The investigators postulated that the use of hyperventilation after induction of anesthesia before CO2 insufflation for laparoscopic surgery in Trendelenburg position would maintain normocapnia and reduce the hemodynamic percussion response of CO2 insufflation.

Condition or disease	Intervention/treatment	Phase
Laparoscopic Cholecystectomy	Procedure: Ventilation	Phase 1

Detailed Description:

The use of laparoscopic techniques has become common in clinical practice. Absorption of carbon dioxide (CO2) from the peritoneal cavity is the potential mechanism for hypercapnia and a rise in the end-tidal carbon dioxide (EtCO2). Mild hypercarbia causes sympathetic stimulation which results in a fivefold increase in arginine vasopressin (AVP), tachycardia, increased systemic vascular resistance, systemic arterial pressure, central venous pressure and cardiac output.1 Severe hypercarbia exerts a negative inotropic effect on the heart and reduces left ventricular function.2 Hemodynamic alterations occur only when the PaCO2 is increased by 30 per cent above the normal levels.

Clearance of CO2 is a function of the adequacy of alveolar ventilation with respect to pulmonary perfusion. Controlled hyperventilation has proved to be superior over spontaneous respiration or controlled normo-ventilation for maintaining normal PCO2 during laparoscopy. During pelvic laparoscopy there was a rapid rise of about 30% in the CO2 load eliminated by the lungs. This quickly reached a plateau and could be compensated by hyperventilation of the lungs with a 30% increase in minute ventilation.

Papadimitriou and co' workers concluded that under sevoflurane anesthesia MAC, prophylactic hyperventilation to ensure mild hypocapnia, (around 33 mmHg) limits the cerebral blood flow velocities enhancing effect of CO2 insufflation, compared with permissive hypercapnia (up to 45 mmHg), during gynecological laparoscopies. However, others advocated that hyperventilation and the head-up position before CO2 insufflation are not sufficient to prevent the CO2-mediated cerebral hemodynamic effects of low-pressure pneumoperitoneum (5-8 mmHg) in children, underwent laparoscopic fundoplication.

Study Design

• Study Type: Interventional (Clinical Trial)
• Actual Enrollment: 100 participants
• Allocation: Randomized
• Intervention Model: Parallel Assignment
• Masking: Triple (Participant, Investigator, Outcomes Assessor)
• Primary Purpose: Prevention
• Official Title: A Prospective Randomized Study of the Effects of Hyperventilation Prior to Carbon Dioxide Insufflation on Hemodynamic Changes During Laparoscopic Cholecystectomy
• Study Start Date: December 2008
• Actual Primary Completion Date: August 2010
• Actual Study Completion Date: September 2010

Arms and Interventions

Arm	Intervention/treatment
Placebo Comparator: The normoventilation group; 15 minutes prior to CO2 insufflation, the patients' lungs were ventilated with a tidal volume (TV) of about 8 mL.kg-1 and respiratory rate (R.R) owas adjusted to maintain an end-tidal CO2 (ETCO2) of 4.6-6 kPa throughout the procedure.	Procedure: Ventilation; Mechanical ventilation was conducted in all the patients with a Datex-Ohmeda Aestiva/5 Smart Ventilator (Madison, WI) through a rebreathing circuit incorporating a CO2 absorber, a heat and moisture exchanger using volume-controlled mode with an inspiratory to expiratory ratio of 1:2.5, and positive end-expiratory pressure (PEEP) of 5 cm H2O. Plateau pressure was kept as low as possible with an upper limit of 30 cm H2O, and the absence of auto-PEEP was ensured by a drop of the expiratory flow to zero on the flow-time curve.
Active Comparator: The hyperventilation group; 15 minutes prior to CO2 insufflation, the patients' lungs were ventilated with a TV of 8 mL.kg-1 with the adjustment of the R.R to maintain an ETCO2 of 4-4.6 kPa, until the end of anaesthesia.	Procedure: Ventilation; Mechanical ventilation was conducted in all the patients with a Datex-Ohmeda Aestiva/5 Smart Ventilator (Madison, WI) through a rebreathing circuit incorporating a CO2 absorber, a heat and moisture exchanger using volume-controlled mode with an inspiratory to expiratory ratio of 1:2.5, and positive end-expiratory pressure (PEEP) of 5 cm H2O. Plateau pressure was kept as low as possible with an upper limit of 30 cm H2O, and the absence of auto-PEEP was ensured by a drop of the expiratory flow to zero on the flow-time curve.

Outcome Measures

Primary Outcome Measures :

1. haemodynamic percussion response [ Time Frame: at 5 and 10 minutes, in supine and Trendelenburg (30° head-down) positions, respectively, before CO2 insufflation and at 15, 30, 45, and 60 min after CO2 insufflation, and at 5 min after desufflation of pneumoperitoneum ]
   changes in mean arterial blood pressure [MAP] and heart rate [H.R].

Secondary Outcome Measures :

1. other hemodynamic and respiratory parameters [ Time Frame: at 5 and 10 minutes, in supine and Trendelenburg (30° head-down) positions, respectively, before CO2 insufflation and at 15, 30, 45, and 60 min after CO2 insufflation, and at 5 min after desufflation of pneumoperitoneum, ]
   systemic vascular resistance index (SVRI), cardiac index (CI), stroke volume index (SVI), PaCO2, EtCO2, arterial to end-tidal CO2 gradient (Pa-EtCO2), respiratory rate and airway pressures were recorded.

Eligibility Criteria

• Ages Eligible for Study: 18 Years to 45 Years (Adult)
• Sexes Eligible for Study: All
• Accepts Healthy Volunteers: No

Criteria

Inclusion Criteria:

• ASA I & II
• aged 18-45 years
• undergoing elective laparoscopic cholecystectomy

Exclusion Criteria:

• history of cardiovascular disease
• respiratory diseases
• neurological disease
• renal disease
• liver disease
• hormonal disease
• pregnancy
• obesity (defined as a body mass index> 29)
• smokers

Contacts and Locations

Locations

Saudi Arabia

King Faisal University

Al Khubar, Eastern, Saudi Arabia, 31952

Sponsors and Collaborators

King Faisal University

Investigators

• Study Director: Mohamed R El Tahan, M.D.; King Faisal University

More Information

• Responsible Party: Dr. Mohamed El Tahan, King Faisal University
• ClinicalTrials.gov Identifier: NCT01182545
• Other Study ID Numbers: 23-10-2007
• First Posted: August 17, 2010
• Last Update Posted: November 19, 2010
• Last Verified: November 2010

Keywords provided by King Faisal University:

Anaesthesia; laparoscopic cholecystectomy; CO2 insufflation; hemodynamic; hyperventilation

Additional relevant MeSH terms:

Hyperventilation; Respiration Disorders; Respiratory Tract Diseases; Signs and Symptoms, Respiratory; Signs and Symptoms