ORIGINAL ARTICLE
Comparison of Standard-pressure and Low-pressure Pneumoperitoneum in Laparoscopic Cholecystectomy: A Double Blinded Randomized Controlled Study Nandhagopal Vijayaraghavan, MBBS, MS,* Sarath Chandra Sistla, MBBS, MS,w Pankaj Kundra, MBBS, MD,z Palghat Hariharan Ananthanarayan, MBBS, MD,y Vilvapathy Senguttuvan Karthikeyan, MBBS, MS,8 Sheik Manwar Ali, MBBS, MS,w Sajith P. Sasi, MBBS, MS,w and Krishnamurthy Vikram, MBBS, MDz
Background and Objective: With the safety of laparoscopic cholecystectomy (LC) having been established, the current stress is on reducing the postoperative morbidity associated with this procedure. Hence, this study was undertaken to compare the effect of low-pressure (8 mm Hg) (LPLC) versus standard-pressure (12 mm Hg) (SPLC) pneumoperitoneum on postoperative pain, respiratory and liver functions, the stress response, and the intraoperative surgeon comfort in patients undergoing LC. Materials and Methods: Patients undergoing LC (n = 43) were randomized into the LPLC (8 mm Hg) group (n = 22) and the SPLC (12 mm Hg) group (n = 21). Postoperative pain, changes in liver function, peak expiration flow rate, C-reactive protein level, and intraoperative surgeon comfort were assessed. Results: The postoperative pain scores (P = 0.003, 0.000, 0.001, and 0.002 at 0, 4, 8, and 24 h), total analgesic requirement (P = 0.001), and the number (total and good) of demands for analgesic in the first 24 hours (P = 0.002 and 0.001) were lower in the LPLC group. The surgeon comfort in the LPLC group was significantly lesser (P = 0.000). The liver function and peak expiration flow rate did not show any significant changes. C-reactive protein levels varied significantly only at 24 hours postoperatively (P = 0.001). Conclusions: The use of low-pressure pneumoperitoneum (8 mm Hg) for LC is associated with a significantly lower postoperative pain. However, the use of this low-pressure pneumoperitoneum can jeopardize the surgeon’s comfort. Key Words: laparoscopic cholecystectomy, standard-pressure pneumoperitoneum, low-pressure pneumoperitoneum, postoperative pain, surgeon comfort
the postoperative morbidity associated with this procedure. Alleviating the postoperative pain associated with LC will go a long way in making LC feasible for a day care setting. Pain after an uneventful laparoscopic procedure is multifactorial in etiology. The sources of pain include the stretched peritoneum, abdominal wall, and diaphragm, the sites of access ports, and the dissected viscera. One of the techniques aimed at reducing postoperative pain is the use of a lower intra-abdominal pressure for performing LC. However, the results of studies comparing the effect of lowpressure versus standard-pressure pneumoperitoneum on postoperative pain in LC are controversial.1–4 Adverse effects associated with pneumoperitoneum can be minimized when laparoscopy is performed at a lower intraabdominal pressure of 7 mm Hg. Hence, this study was undertaken to compare the effect of low-pressure (8 mm Hg) versus standard-pressure (12 mm Hg) pneumoperitoneum on postoperative pain, derangements in various organ systems, the stress responses, and the comfort of the operating surgeon in patients undergoing LC.
METHODS This was a hospital-based, double blind randomized control study, conducted on 43 patients undergoing elective LC in the Department of General Surgery in a tertiary care institute in South India. The study was cleared by the Institute Research Council and Institute Ethics Committee (JIPMER, Pondicherry, India).
(Surg Laparosc Endosc Percutan Tech 2014;24:127–133)
Study Population
L
aparoscopic cholecystectomy (LC) is the gold standard procedure for cholelithiasis. With the safety of LC having been established, the current focus is on reducing
Received for publication September 26, 2012; accepted October 16, 2012. From the Departments of *Plastic Surgery; wSurgery; zAnesthesiology and Critical Care; yBiochemistry; 8Urology, Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER), Pondicherry; and zDepartment of Community Medicine, University College of Medical Sciences (UCMS), New Delhi, India. The authors declare no conflicts of interest. Reprints: Sarath Chandra Sistla, MBBS, MS, Department of Surgery, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry 605006, India (e-mails: sarathsistla@ hotmail.com; [email protected]). Copyright r 2014 by Lippincott Williams & Wilkins
Surg Laparosc Endosc Percutan Tech
Forty-three consecutive patients undergoing elective LC under general anesthesia, above 18 years of age, of either sex, and belonging to American Society of Anesthesiologists physical status I and II were included in the study after obtaining a written informed consent. Patients with restrictive or obstructive pulmonary disease, cardiac dysfunction, pregnancy, extensive upper abdominal incision, complicated gall stone disease (empyema of the gall bladder, gangrene of the gall bladder, and acute gall stone pancreatitis, and a history of cholangitis) and those converted to open cholecystectomy were excluded. Using PS software (power and sample size calculation software) 2.1.31, considering the difference in the pain score in the study conducted by Perrakis et al,3 to detect a 35% difference in pain score with 80% power at 5% significance level, the sample size was calculated to be 20 patients in each arm for our study.
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Vijayaraghavan et al
Surg Laparosc Endosc Percutan Tech
Randomization, Allocation Concealment, and Blinding Patients were randomized to the low-pressure LC (LPLC) group, who underwent surgery at pneumoperitoneum of 8 mm Hg and the standard-pressure LC (SPLC) group, who underwent surgery at pneumoperitoneum of 12 mm Hg by block randomization (block size of 4) performed using Microsoft Excel 2007. Allocation concealment was performed using the serially numbered opaque sealed envelope technique. Randomization and sealed envelopes were prepared by a person independent of the investigators, the surgeon, and the anesthetist involved in patient care. Envelopes were opened on the day of surgery outside the operating room by a scrub nurse not involved in the research. The patient and the investigator who assessed the outcomes (pain, liver function, respiratory function, stress response, and surgeon comfort) were also blinded. Hence, the study was double blind. At the end of the study, the groups were decoded and analyzed (Fig.1).
Intervention A standard anesthesia protocol was used for all our patients. All patients were premedicated with diazepam 0.2 mg/kg the night before the surgery and on the morning of the surgery along with oral metoclopramide 10 mg. Morphine 0.15 mg/kg intramuscularly was administered 60 minutes before surgery. Induction of anesthesia was performed with a sleep dose of thiopentone. Tracheal intubation was accomplished with 0.15 mg/kg vecuronium
Volume 24, Number 2, April 2014
bromide. Anesthesia was maintained with 1.0 MAC of isoflurane and 66% N2O in 33% O2 through a circle system. Incremental doses of vecuronium and morphine were used to maintain neuromuscular blockade and analgesia during the intraoperative course. Controlled ventilation of lungs was achieved with a tidal volume of 8 mL/kg at a frequency of 12 breaths/min. Positive end expiratory pressure (PEEP) of 5 and 10 cm was applied before pneumoperitoneum in groups LPLC and SPLC, respectively. Capnoperitoneum was created using a Verres needle by the closed technique to the pressure set by the scrub nurse on the basis of the patient group. LC in both groups was performed using a standard 4-port technique with the Karl-Storz laparoscope. Intraoperative complications (bleeding and gall bladder perforation) and duration of surgery were noted. Cases converted to open cholecystectomy were excluded from the study. In cases of poor visibility, capnoperitoneum can be increased at the request of the surgeon and it was noted. End-operatively, port site infiltration with 5 mL of 0.25% bupivacaine was used routinely. Subhepatic drain placement was performed on the basis of the discretion of the operating surgeon but not routinely. The surgeon comfort was assessed using 3 parameters (visibility, visibility at suction, and space for dissection) on a numeric rating scale of 1 to 5. Postoperative pain intensity was evaluated with a 10-point Visual Analog Score (VAS) on admission into the surgical intensive care unit.5 Intravenous (IV) patient-controlled analgesia (PCA) was then provided to the patient,
FIGURE 1. Flow diagram. Flow of participants through the study. LPLC indicates low-pressure laparoscopic cholecystectomy; SPLC, standard-pressure laparoscopic cholecystectomy.
128 | www.surgical-laparoscopy.com
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2014 Lippincott Williams & Wilkins
Surg Laparosc Endosc Percutan Tech
Volume 24, Number 2, April 2014
and IV doses of morphine were delivered by the PCA pump at 1 mg bolus doses on patient’s demand. The lock-out interval was set at 15 minutes. The pain scores were assessed at 0, 4, 8, and 24 hours postoperatively, and morphine requirements (mg) were recorded for the first 24 hours. Presence of nausea, vomiting, urticaria, urinary retention, respiratory depression, use of antiemetics, bradycardia, hypotension, and sedation were recorded. A bolus dose of 1 mg of IV morphine was administered every 10 minutes until a score of r3 on the VAS was attained. Liver function tests (LFTs) including detection of bilirubin, aspartate transaminase (AST), alanine transaminase (ALT), and alkaline phosphatase levels were performed preoperatively and at 24 and 48 hours after surgery. Peak expiration flow rate (PEFR) (L/min) was measured preoperatively and at 24 hours after surgery using BreatheO meter (CIPLA). C-reactive protein (CRP) levels (mg/dL) were measured preoperatively and at 24, 48, and 72 hours after surgery, using the ELISA technique (high-sensitivity CRP ELISA kit; Diagnostics Biochem Canada Inc.).
Outcome The primary outcome variable was total postoperative morphine requirements (mg) in the 24-hour postoperative period. The secondary outcome variables were VAS, LFTs, CRP levels, and PEFR at specific time intervals and surgeon comfort during the surgical procedure.
Statistical Analysis Statistical analysis was performed using SPSS version 17 for Windows (SPSS, Chicago, IL). The variables were summarized using mean, SE, median, interquartile range (IQR), or percentages on the basis of the characteristics of the variable. The data in each group were considered nonparametric because the sample size was 22 in LPLC and 21 in HPLC. Mann-Whitney U test was used for analysis of the unpaired data. Paired data were analyzed using Freidman analysis of variance. The P value of
Comparison of Standard-pressure and Low-pressure Pneumoperitoneum in Laparoscopic Cholecystectomy: A Double Blinded Randomized Controlled Study Nandhagopal Vijayaraghavan, MBBS, MS,* Sarath Chandra Sistla, MBBS, MS,w Pankaj Kundra, MBBS, MD,z Palghat Hariharan Ananthanarayan, MBBS, MD,y Vilvapathy Senguttuvan Karthikeyan, MBBS, MS,8 Sheik Manwar Ali, MBBS, MS,w Sajith P. Sasi, MBBS, MS,w and Krishnamurthy Vikram, MBBS, MDz
Background and Objective: With the safety of laparoscopic cholecystectomy (LC) having been established, the current stress is on reducing the postoperative morbidity associated with this procedure. Hence, this study was undertaken to compare the effect of low-pressure (8 mm Hg) (LPLC) versus standard-pressure (12 mm Hg) (SPLC) pneumoperitoneum on postoperative pain, respiratory and liver functions, the stress response, and the intraoperative surgeon comfort in patients undergoing LC. Materials and Methods: Patients undergoing LC (n = 43) were randomized into the LPLC (8 mm Hg) group (n = 22) and the SPLC (12 mm Hg) group (n = 21). Postoperative pain, changes in liver function, peak expiration flow rate, C-reactive protein level, and intraoperative surgeon comfort were assessed. Results: The postoperative pain scores (P = 0.003, 0.000, 0.001, and 0.002 at 0, 4, 8, and 24 h), total analgesic requirement (P = 0.001), and the number (total and good) of demands for analgesic in the first 24 hours (P = 0.002 and 0.001) were lower in the LPLC group. The surgeon comfort in the LPLC group was significantly lesser (P = 0.000). The liver function and peak expiration flow rate did not show any significant changes. C-reactive protein levels varied significantly only at 24 hours postoperatively (P = 0.001). Conclusions: The use of low-pressure pneumoperitoneum (8 mm Hg) for LC is associated with a significantly lower postoperative pain. However, the use of this low-pressure pneumoperitoneum can jeopardize the surgeon’s comfort. Key Words: laparoscopic cholecystectomy, standard-pressure pneumoperitoneum, low-pressure pneumoperitoneum, postoperative pain, surgeon comfort
the postoperative morbidity associated with this procedure. Alleviating the postoperative pain associated with LC will go a long way in making LC feasible for a day care setting. Pain after an uneventful laparoscopic procedure is multifactorial in etiology. The sources of pain include the stretched peritoneum, abdominal wall, and diaphragm, the sites of access ports, and the dissected viscera. One of the techniques aimed at reducing postoperative pain is the use of a lower intra-abdominal pressure for performing LC. However, the results of studies comparing the effect of lowpressure versus standard-pressure pneumoperitoneum on postoperative pain in LC are controversial.1–4 Adverse effects associated with pneumoperitoneum can be minimized when laparoscopy is performed at a lower intraabdominal pressure of 7 mm Hg. Hence, this study was undertaken to compare the effect of low-pressure (8 mm Hg) versus standard-pressure (12 mm Hg) pneumoperitoneum on postoperative pain, derangements in various organ systems, the stress responses, and the comfort of the operating surgeon in patients undergoing LC.
METHODS This was a hospital-based, double blind randomized control study, conducted on 43 patients undergoing elective LC in the Department of General Surgery in a tertiary care institute in South India. The study was cleared by the Institute Research Council and Institute Ethics Committee (JIPMER, Pondicherry, India).
(Surg Laparosc Endosc Percutan Tech 2014;24:127–133)
Study Population
L
aparoscopic cholecystectomy (LC) is the gold standard procedure for cholelithiasis. With the safety of LC having been established, the current focus is on reducing
Received for publication September 26, 2012; accepted October 16, 2012. From the Departments of *Plastic Surgery; wSurgery; zAnesthesiology and Critical Care; yBiochemistry; 8Urology, Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER), Pondicherry; and zDepartment of Community Medicine, University College of Medical Sciences (UCMS), New Delhi, India. The authors declare no conflicts of interest. Reprints: Sarath Chandra Sistla, MBBS, MS, Department of Surgery, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry 605006, India (e-mails: sarathsistla@ hotmail.com; [email protected]). Copyright r 2014 by Lippincott Williams & Wilkins
Surg Laparosc Endosc Percutan Tech
Forty-three consecutive patients undergoing elective LC under general anesthesia, above 18 years of age, of either sex, and belonging to American Society of Anesthesiologists physical status I and II were included in the study after obtaining a written informed consent. Patients with restrictive or obstructive pulmonary disease, cardiac dysfunction, pregnancy, extensive upper abdominal incision, complicated gall stone disease (empyema of the gall bladder, gangrene of the gall bladder, and acute gall stone pancreatitis, and a history of cholangitis) and those converted to open cholecystectomy were excluded. Using PS software (power and sample size calculation software) 2.1.31, considering the difference in the pain score in the study conducted by Perrakis et al,3 to detect a 35% difference in pain score with 80% power at 5% significance level, the sample size was calculated to be 20 patients in each arm for our study.
Volume 24, Number 2, April 2014
www.surgical-laparoscopy.com |
127
Vijayaraghavan et al
Surg Laparosc Endosc Percutan Tech
Randomization, Allocation Concealment, and Blinding Patients were randomized to the low-pressure LC (LPLC) group, who underwent surgery at pneumoperitoneum of 8 mm Hg and the standard-pressure LC (SPLC) group, who underwent surgery at pneumoperitoneum of 12 mm Hg by block randomization (block size of 4) performed using Microsoft Excel 2007. Allocation concealment was performed using the serially numbered opaque sealed envelope technique. Randomization and sealed envelopes were prepared by a person independent of the investigators, the surgeon, and the anesthetist involved in patient care. Envelopes were opened on the day of surgery outside the operating room by a scrub nurse not involved in the research. The patient and the investigator who assessed the outcomes (pain, liver function, respiratory function, stress response, and surgeon comfort) were also blinded. Hence, the study was double blind. At the end of the study, the groups were decoded and analyzed (Fig.1).
Intervention A standard anesthesia protocol was used for all our patients. All patients were premedicated with diazepam 0.2 mg/kg the night before the surgery and on the morning of the surgery along with oral metoclopramide 10 mg. Morphine 0.15 mg/kg intramuscularly was administered 60 minutes before surgery. Induction of anesthesia was performed with a sleep dose of thiopentone. Tracheal intubation was accomplished with 0.15 mg/kg vecuronium
Volume 24, Number 2, April 2014
bromide. Anesthesia was maintained with 1.0 MAC of isoflurane and 66% N2O in 33% O2 through a circle system. Incremental doses of vecuronium and morphine were used to maintain neuromuscular blockade and analgesia during the intraoperative course. Controlled ventilation of lungs was achieved with a tidal volume of 8 mL/kg at a frequency of 12 breaths/min. Positive end expiratory pressure (PEEP) of 5 and 10 cm was applied before pneumoperitoneum in groups LPLC and SPLC, respectively. Capnoperitoneum was created using a Verres needle by the closed technique to the pressure set by the scrub nurse on the basis of the patient group. LC in both groups was performed using a standard 4-port technique with the Karl-Storz laparoscope. Intraoperative complications (bleeding and gall bladder perforation) and duration of surgery were noted. Cases converted to open cholecystectomy were excluded from the study. In cases of poor visibility, capnoperitoneum can be increased at the request of the surgeon and it was noted. End-operatively, port site infiltration with 5 mL of 0.25% bupivacaine was used routinely. Subhepatic drain placement was performed on the basis of the discretion of the operating surgeon but not routinely. The surgeon comfort was assessed using 3 parameters (visibility, visibility at suction, and space for dissection) on a numeric rating scale of 1 to 5. Postoperative pain intensity was evaluated with a 10-point Visual Analog Score (VAS) on admission into the surgical intensive care unit.5 Intravenous (IV) patient-controlled analgesia (PCA) was then provided to the patient,
FIGURE 1. Flow diagram. Flow of participants through the study. LPLC indicates low-pressure laparoscopic cholecystectomy; SPLC, standard-pressure laparoscopic cholecystectomy.
128 | www.surgical-laparoscopy.com
r
2014 Lippincott Williams & Wilkins
Surg Laparosc Endosc Percutan Tech
Volume 24, Number 2, April 2014
and IV doses of morphine were delivered by the PCA pump at 1 mg bolus doses on patient’s demand. The lock-out interval was set at 15 minutes. The pain scores were assessed at 0, 4, 8, and 24 hours postoperatively, and morphine requirements (mg) were recorded for the first 24 hours. Presence of nausea, vomiting, urticaria, urinary retention, respiratory depression, use of antiemetics, bradycardia, hypotension, and sedation were recorded. A bolus dose of 1 mg of IV morphine was administered every 10 minutes until a score of r3 on the VAS was attained. Liver function tests (LFTs) including detection of bilirubin, aspartate transaminase (AST), alanine transaminase (ALT), and alkaline phosphatase levels were performed preoperatively and at 24 and 48 hours after surgery. Peak expiration flow rate (PEFR) (L/min) was measured preoperatively and at 24 hours after surgery using BreatheO meter (CIPLA). C-reactive protein (CRP) levels (mg/dL) were measured preoperatively and at 24, 48, and 72 hours after surgery, using the ELISA technique (high-sensitivity CRP ELISA kit; Diagnostics Biochem Canada Inc.).
Outcome The primary outcome variable was total postoperative morphine requirements (mg) in the 24-hour postoperative period. The secondary outcome variables were VAS, LFTs, CRP levels, and PEFR at specific time intervals and surgeon comfort during the surgical procedure.
Statistical Analysis Statistical analysis was performed using SPSS version 17 for Windows (SPSS, Chicago, IL). The variables were summarized using mean, SE, median, interquartile range (IQR), or percentages on the basis of the characteristics of the variable. The data in each group were considered nonparametric because the sample size was 22 in LPLC and 21 in HPLC. Mann-Whitney U test was used for analysis of the unpaired data. Paired data were analyzed using Freidman analysis of variance. The P value of
