A Comparison of Gasless Mechanical and Conventional Carbon Dioxide Pneumoperitoneum Methods for Laparoscopic Cholecystectomy

A Comparison of Gasless Mechanical and Conventional Carbon Dioxide Pneumoperitoneum Methods for Laparoscopic Cholecystectomy Anna-Maria Koivusalo, MD*, Ilmo Kellokumpu, Ilkka Tikkanen, MD, rhD$, Heikki Mskisalo, MD, Departments Pharmacology

rhDt,

Mika Scheinin, MD, rhD& Leena Lindgren, MD, rhD*

PhDt,

of *Anaesthesia, tsurgery, and *Medicine, University of Helsinki, and Clinical Pharmacology, University of Turku, Turku, Finland

Carbon dioxide (CO,) insufflation with increased intraabdominal pressure (IAP) has adverse hemodynamic, pulmonary, and renal effects. To avoid these problems, an abdominal wall lift method with a retractor was used to provide the surgical view without CO2 insufflation. Twenty-six patients undergoing elective laparoscopic cholecystectomy were randomly allocated to either the gasless, retractor group, or conventional CO, pneurnoperitoneum group (CPP). Hemodynamic data, ventilatory variables, urine output, urine oxygen tension, and blood samples for determining stress hormones were collected throughout the perioperative period. Patients in the retractor group had lower mean arterial pressure, heart rate, and central venous pressure (P < 0.001). They also had higher pulmonary dynamic compliance and needed a lower minute volume of ventilation to achieve normocarbia (P < 0.001). Urine output and oxygen tension in

C

of pneumoperitoneum with CO, insufflation for laparoscopic procedures induces a cardiovascular response characterized by abrupt hypertension and tachycardia (1). This response increasesmyocardial oxygen demand. CO, is readily absorbed from the peritoneal cavity into the circulation, resulting in hypercarbia and respiratory acidosis. CO, can be removed only by an increasing minute volume of ventilation (2). Pneumoperitoneum causesintraabdominal distension followed by a decrease in pulmonary dynamic compliance (3,4). Low compliance, together with an increased minute volume of ventilation, is accompanied by peak airway pressures (4). A decrease in urine output occurs during laparoscopic procedures (1,5-7). Increased concentrations of plasma renin activity (PRA) have been measured after reation

Accepted for publication September 10, 1997. Address correspondence and reprint requests to Anna-Maria Koivusalo, MD, Department of Anaesthesia, IV Department of Surgery, Helsinki University, Kasarmikatu 11-13, FIN-00130 Helsinki, Finland. 01997 by the International 0003-2999/98/$5.00

MD,

Anesthesia

Helsinki;

and $jDepartment

of

urine were higher (P < 0.05) with the retractor method than with CPP. Increase in plasma renin activity (P < 0.05) and decrease in core temperature (P < 0.001) were smaller with the gasless method than with CPP. The gasless method for laparoscopic cholecystectomy might be beneficial, especially in patients with compromised cardiorespiratory or renal function. Implications: Totally gasless laparoscopic cholecystectomy was compared with conventional pressure pneumoperitoneum with CO, insufflation. The gasless method resulted in more stable hemodynamics and pulmonary function, as well as higher urine, output than conventional pressure pneumoperitoneum. No changes in renal oxygenation was seen with the gasless method, compared with conventional pressure pneumoperitoneum. (Anesth Analg 1998;86:153-8)

the induction of pneumoperitoneum (1,9).’ Increased intraabdominal pressure (IAP) and the local compression of renal vessels possibly increase PRA, causing a decline in urine output (1,lO). The core temperature decreasesapproximately 0.2”C with room temperature CO, insufflation for laparoscopic cholecystectomy (1). Cooling causesperipheral vasoconstriction (11). Postoperative shivering after intraoperative cooling increasesoxygen consumption (12). The abdominal wall lift technique (13) with a mechanical retractor has been introduced to avoid the adverse effects caused by insufflated CO, and increased IAP. We have recently shown that during laparoscopic cholecystectomy with combined abdominal wall lift method and minimal CO, insufflation, changes in hemodynamics, pulmonary and renal function, and neuroendocrine responses were minimal compared with 1 Joris J, Lamy M. Neuroendocrine changes during toneum for laparoscopic cholecystectomy [abstract]. 1993;70:A33.

pneumoperiBr J Anaesth

Research Society Anesth

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those observed with conventional insufflatjon (1,3). There are no human data on the effects of a totally gasless method for laparoscopic cholecystectomy. The aim of our prospective randomized study was to compare the conventional pressure pneumoperitoneum (CPP) with the totally gasless technique in regard to hemodynamics, pulmonary and renal function, neuroendocrine response, and changes in core temperature during and after laparoscopic cholecystectomy.

Methods The study protocol was approved by the ethics committee of our hospital, and written, informed consent was obtained from the patients. Twenty-six consecutive ASA physical status I or II patients undergoing elective laparoscopic cholecystectomy were randomly allocated to two groups. In one group, the operation was performed using CPP (IAP 12-13 mm Hg) with room temperature CO2 insufflation (CPP group). In the other group, a mechanical retractor (LaparoliftTM; Origin Medsystems Inc., Menlo Park, CA) was used to elevate the anterior part of the abdominal wall upward by lo-15 cm with the force of 12-15 kg (Figure 1) (13). No COz was used (retractor group). All operations were performed by the same experienced surgeon (IK). All patients were given antithrombotic prophylaxis with low molecular weight heparin. Patients were premedicated with oral diazepam 0.2 mg/kg. Glycopyrrolate 3 Fg/kg intravenously (IV) was given to all patients 1 h before the procedure. Before the induction of anesthesia, acetated Ringer’s solution 8 mL/kg was infused. During the operation, 10 mL * kg-’ * h-l of acetated Rin er’s solution and hydroxyethyl starch (Plasmafusin 8 ; Pharmacia AB, Halden, Norway) 500 mL were administered. A warm (39°C) water bath mattress and warmed fluids were used. Anesthesia was induced with alfentanil 20 pg/kg and propofol 1.5-2 mg/kg. An extra bolus of alfentanil of 20 pg kg-’ was given before the surgery. Muscle relaxation achieved by the administration of atracurium. Anesthesia was maintained with desflurane at an end-tidal

Figure

1. Schematic

illustration

of the retractor

method.

ANESTH ANALG 1998;86:153-8

concentration of 6.1% (1 minimum alveolar anesthetic concentration) and oxygen in air (fraction of inspired oxygen 0.4). No nitrous oxide was used. Analgesia was achieved using alfentanil as an infusion (range l-200 pg * kg-i . h-l) to avoid an arterial blood pressure increase of more than 25% from the preanesthetic value. The total amount of alfentanil and fluids was registered. Ventilation was controlled with 10 breaths/min. Minute volume of ventilation was increased as needed to maintain the end-tidal CO, concentration within normal limits (4.5%-5.0%). After the induction of anesthesia, a urinary bladder catheter, a nasogastric tube, and a tympanic membrane temperature sensor (Mon-a-therm Tympani?; Mallincrodt Medical, Athlone, Ireland) were inserted. The right subclavian vein was cannulated by using the cubital vein (the adequate position of the tip of the 70-cm catheter was confirmed by using the AlphaCard@ [Sterimed, Gesellschaft fur Medizinischen Bedarf GmbH, Germany] after the changes in electrocardiogram I’ wave) (14). A radial artery was cannulated for pressure monitoring. The pressure transducers were positioned at the mid-thoracic level (the transducer was adjusted when using the head-up tilt during the procedure). IAP was kept between 12 and 13 mm Hg in the CPP group. Urine output was registered continuously. To achieve diuresis of 1 mL * kg-i - h-i, 100 mL of 15% mannitol was given; if not this was not adequate, furosemide 5 mg IV was administered. The total amount of intraoperative diuretics and CO, was recorded. Heart rate (HR); direct systolic pressure, diastolic pressure, and mean arterial pressure (MAP); peripheral arterial oxygen saturation (SpoJ; central venous pressure; end-tidal CO, concentration; expired minute volume of ventilation; pulmonary dynamic compliance; end-tidal desflurane concentration; and tympanic membrane temperature were recorded before skin incision; after 5, 10, 15, 20, 25, 30, 35, 40, 45, and 55 min of insufflation; and before tracheal extubation. Data were collected up to 3 h postoperatively. Oxygen tension in urine (Puo,)was measured from the urinary bladder by using a miniature polarographic electrode (ContinuCath Biomedical Sensors; Pfizer, NY), which was inserted inside the urinary catheter. Blood samples for the determination of plasma renin activity (IRA), norepinephrine (NE), epinephrine (E), and antidiuretic hormone (ADH) were collected from the subclavian catheter before skin incision; 15, 35, and 55 min after the beginning of insufflation; and 1 h postoperatively. Blood samples were collected into prechilled polypropylene tubes containing EDTA and immediately placed on ice. The tubes were centrifuged at 0°C within 30 min, and the plasma was stored in polypropylene tubes at -70°C until analysis. PRA and ADH were determined by using a radioimmunoassay

ANESTH ANALG 1998;86:153-8

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(15). Plasma concentrations of catecholamines were measured by using high-performance liquid chromatography with electrochemical detection (16). The intraassay coefficients of variation were approximately 2% for NE and 10% for E at physiological concentrations. Catecholamines, especially NE, are selectively taken up by the lungs (17). Therefore, venous blood was sampled from the superior vena cava. For statistical analysis, the changes within a group were tested by using one-way analysis of variance (ANOVA) with Fisher’s protected least significant difference. The differences between the groups were analyzed by using two-way ANOVA. Correlation between MAP and PRA, as well as between MAP and ADH, were calculated. The calculations were performed with Stat View 512TM software (Brain Power Inc., Calabasas,CA). Data are expressed as mean 2 SD.

Results The two groups were comparable in age, weight, height, ASA physical status, gender, anesthetic data, and use of intraoperative fluids (Table 1). The amount of CO, needed in the CPP group was 55 + 34 L (P < 0.001 between the groups). The duration of the operation was 85 + 25 min in the CPP group and 108 ? 28 min in the retractor group (P < 0.05). There were no perioperative anesthetic or surgical complications. MAP increased significantly in the CPP group during the first 15 min of insufflation (P < 0.001) but remained at baseline levels in the retractor group (P < 0.01 between the groups) (Figure 2). During the first 15 min of insufflation, the HR response in the CPP group was more marked than that in the retractor group (P < 0.01). CVP increased by 146% in the CPP group during the first 5 min of insufflation but remained at baseline level in the retractor group. CVP was significantly higher in the CPP group throughout the operation and until 1 h postoperatively (P < 0.05) (Figure 2). Table

1. Patients’ Demographic and Intraoperative

Variables CPP group (n = 13)

Retractor group (n = 13)

Age (yr), mean (range) 47 (28-71) 41(27-59) 167? 6 165 t 8 Height (‘cm) We&ht (kg) 72 2 15 70 t 13 9/4 9/4 ASA physical status I/II Sex ratio (F/M) 12/l 12/l Acetated Ringer’s solution (mL) 1450+ 530 1600+-390 Hvdroxvethvl starch (mL) 530 2 90 560 2 155 Aifentanil (kg/kg) ’ ’ 104 ” 76 84 2 70 Values are mean CPP = conventional

+ SD. pneumoperitoneum.

MECHANICAL

VS CO,

KOIVUSALO ET AL. FOR LAPAROSCOPY

155

The Spo, was more than 97% throughout the perioperative period in both groups. Pulmonary dynamic compliance decreased significantly (P < 0.001) during the first 5 min of insufflation in the CPP group, remained at that level throughout the operation, and returned to the baseline level at deflation. There were no changes in pulmonary compliance in the retractor group (P < 0.01 between the groups) (Figure 3). The minute volume of ventilation needed to be increased during the first 15 min of insufflation in the CPP group (P < 0.001) to achieve normoventilation. No changes were required in the retractor group. Urine output during the first 30 min of the operation was 0.38 + 0.71 mL/kg in the CPP group and 1.14 ? 0.92 mL/kg in the retractor group (P < 0.05). During the next 30 min, these figures were 0.28 ? 0.8 mL/kg and 0.49 ? 0.4 mL/kg, respectively. Diuresis ceased in seven patients in the CPP group and in one patient in the retractor group (P < 0.05). Eleven patients in the CPP group and four patients in the retractor group required mannitol. During the postanesthesia care unit (PACU) period, there were no differences in urine output between the study groups. Puo, decreased during the first 5 min of insufflation in the CPP (P < 0.05) group but remained at the baseline level in the retractor group. During pneumoperitoneum, Puo, was not measured because urine output was too low. During the 3-h PACU period, Puo, remained at a significantly lower level in the CPP group than in the retractor group (P < 0.05) (Figure 4). PRA concentrations increased significantly (P < 0.05) only in the CPP group during the first 15 min of insufflation and stayed at that level throughout the operation (P < 0.05 between the groups) (Figure 4). There was a positive correlation between MAP and PRA at 15 min (Y = 0.48, P < 0.05) and 35 min (Y = 0.44, P < 0.05) of operation. NE and E concentrations increased in both groups. There were no differences between the groups. ADH concentrations tended to be somewhat lower in the CPP group than in the retractor group, but the difference was not statistically significant (Table 2). No correlation was found between MAP and ADH concentrations. Core temperature decreased by 0.5”C in the CPP group during insufflation and remained at baseline level in the retractor group (P -=c0.001, between the groups). Four patients in the CPP group and one patient in the retractor group had shivering during the PACU phase (P = not significant).

Discussion In the current study, gaslesslaparoscopic cholecystectomy resulted in smaller hemodynamic and pulmonary changes compared with CPP. The urinary output

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Figure 2. Mean

Pre

-7

02

5

15

25

35

of laparoscopy (mm)

45

55

Pm

5

15 25 35 45 55 of laparoscopy (mm)

7% 70.

E 0 Tg

65.

8

55.

L-5

50.

E 8 *

45.

g

35.

60.

40.

pre

5

15 25 35 45 of laparoscopy (min)

55

exf

Figure 3. Pulmonary

compliance during the study. tP < 0.001 from the baseline (one-wav analvsis of variance). *P < 0.001 difference in the response bekeen ‘the groups (&o-way analysis of variance). Pre = before laparoscopy, ext = tracheal extubation. 0 = conventional pneumoperitoneum group, 0 = retractor group.

was significantly lower when the conventional technique was used. Arterial blood pressures, HR, and CVP increased significantly with CPP. High IAP increases also cardiac afterload and systemic vascular resistance (18). Therefore, myocardial oxygen demand is increased and coronary perfusion is decreased. The increase in CVP and its slow return to preanesthetic level may have resulted from compression of the inferior vena cava and splanchnic vessels (3,18). Intraabdominal distension elevates the diaphragm, which also increases intrathoracic pressure. In our retractor group, CVP remained at a significantly lower level compared with the CPP group. The intravascular fluid administration was the same in the two groups, which indicates that the increase in CVP may only be due to pneumoperitoneum. It can be speculated that with the retractor method, the risk of an ischemic cardiac episode is lower. CO, causes direct and indirect hemodynamic effects. CO, directly dilates peripheral arterioles and depresses myocardial contractility. Indirectly, CO, activates the central nervous system and evokes sympathoadrenal activation, increasing myocardial contractility and causing tachycardia and hypertension.

0 30mm lh 2h 3h after arrwal in PACU

arterial pressure and central venous pressure (CVP) during laparoscopic cholecystectomy. 0 = conventional pneumoperitoneum group, 0 = retractor group. tP < 0.001 from baseline (one-way analysis of variance). *P < 0.001 the difference in the response between the groups (two-way analysis of variance). Pre = before laparoscopy, PACU = postanesthesia care unit

Exogenous CO, increases peripheral vascular resistance and reduces the cardiac output during mechanical ventilation (19). During CPP, the indirect effects of CO, seem to dominate. CO, insufflated into the abdominal cavity can cause serious gas emboli, leading to life-threatening cardiac arrhythmias (20). Increased IAP because of CPP decreases the venous return from the lower extremities and increases femoral venous pressure (3,21). Hence, there is a potential risk of deep venous thrombosis or pulmonary embolism (21). In our previous study with minimal CO, insufflation, femoral venous pressure did not increase. Therefore, we assume that femoral venous pressure remains unchanged and that there is no risk of embolus with the gasless method. Pulmonary compliance was significantly higher with the retractor than with CPP method. The decrease in pulmonary compliance caused by CPP was similar to that reported previously (3,4). Abdominal distension elevates the diaphragm and the abdominal part of the chest wall, restricting lung expansion. Increased minute volume is necessary for adequate ventilation. Lung restriction and increased minute volume increase airway pressures and decrease pulmonary dynamic compliance. This may cause hemodynamic instability, especially in obese patients. Increased airway pressures are associated with pulmonary barotrauma (22). CO, is rapidly absorbed into circulation through the peritoneum, resulting in hypercarbia and respiratory acidosis. We have shown previously that ventilatory effort is needed to eliminate insufflated COz, and during the recovery phase (23). Excess CO2 can be easily managed by hyperventilation during surgery. After tracheal extubation, the spontaneous ventilatory drive is blunted, to some degree, by the residual effects of opioids (23). Underlying pulmonary pathology may also retard elimination of CO, (24). Less ventilatory effort is needed during and after laparoscopy when the gasless retractor method is used. Renal function deteriorates at an IAP of 10 mm Hg (10). Insufflation of cool CO, into the abdominal cavity may cause renal vasoconstriction (7). The primary renal effect by CO, insufflation is a decrease in renal venous flow, which may last up to two hours after deflation (6). In addition, renal cortical perfusion decreases during laparoscopy (5). In our study, urine

ANESTH ANALG 1998;86:153-8

KOIVUSALO ET AL. VS CO, FOR LAPAROSCOPY

GASLESS MECHANICAL

Figure 4. Plasma renin activity and urine oxygen tension (Puo,) during the study. tP < 0.05 from baseline (one-way analysis of variance). *P < 0.05 the difference in the response between the groups (two-way analysis of variance). pre = before laparoscopy, PACLJ = postanesthesia care unit. 0 = conventional pneumoperitoneum group, 0 = retractor group.

-: 18. E 16. rE 14. @ 1% s2 IO. 8r: 8. @ 6. 2 ‘+ h2 2-

Pre

15

Table 2. Changes in Stress Hormone Concentrations

35 of lapam~copy

(mm)

55

PACU 60 m m

pm 5 15 0 Of laparoscopy (mm)

157

30 60 120 160 after arrwal m PACU (mm)

During Laparoscopic Cholecystectomy During surgery (min)

NE (nmol/L) CPP Retractor E (nmol/L) CPP Retractor ADH

Pre

15

35

55

PACU

0.81 t 0.44 1.00 2 0.49

2.20 t 0.58$ 1.80 t 0.77$

1.90 + 0.71$ 1.57 2 0.47t

1.40 -t- 0.46t 1.52 L 0.51$

1.52 ? 0.85$ 1.54 2 0.76*

0.01 If: 0.03

0.27 + 0.24* 0.27 t 0.33

0.13 + 0.13 0.32 t 0.45

0.09 t 0.14 0.17 + 0.21

0.65 2 0.571) 0.62 t 0.67$

44.4 t 72.3* 76.2 ? 112.0*

11.5 k 7.2 49.7 2 73.4

13.1 + 12.1 40.3 -c 72.9

84.5 + 69.4$ 51.5 + 41.5*

0.03 t 0.05

(pg/mL)

CPP Retractor

6.8 t 2.7

8.1 t 6.2

Values are mean k SD. CPP = conventional pneumoperitoneum, NE = norepinephrine, _ , postanesthetic care unit. * P < 0.05, t P < 0.01, $ P < 0.001 from the baseline value.

E = epinephrine,

output was lower and PR4 concentration was higher with the CPP method than with the retractor method. This observed decrease in urine output is in agreement with earlier studies (1,5,6). Diminished renal blood flow is an important activator of the renin/ angiotensin/aldosterone system (25). Angiotensin II causes renal and systemic vasoconstriction and a release of catecholamines (26) and directs the renal blood flow toward the medulla (27). Renal vasoconstriction is one of the main factors of acute tubular necrosis. Warm CO, maintains urine output during laparoscopic surgery lasting up to three hours (7). Cooling is probably one of the factors that affects urine output and renal oxygenation. Avoiding CPP and high IAP by using the retractor method might be beneficial in patients with limited renal function, because the renin/angiotensin/aldosterone system is not activated. Puo, reflects the oxygen balance in the medulla of the kidneys. It decreases as a consequence of renal vasoconstriction (28,29). Puo, decreased in our CPP group but remained unchanged when the gasless method was used. Recent advances suggest that an impaired oxygen balance of the kidney medulla is a major pathogenesis of acute tubular failure. Our results with CPP suggest that during CO, insufflation and elevated IAP, renal oxygenation deteriorates. Puo, is a more sensitive predictor of renal blood flow than cardiac index or MAP (30). Thus, oxygen delivery

ADH

= antidiuretic

hormone,

pre = before

operation,

PACU

=

into the renal medulla may also deteriorate during and after CPP. An increase in PRA and NE is considered to be a stress response to CO, insufflation (8). Our results with PRA, NE, and E concentrations in the CPP group were similar to those reported in previous earlier studies (1,8,9). Increases in NE and E concentrations were quite modest and did not indicate any major sympathoadrenal activation. An NE concentration of approximately 10 times that of the baseline value is probably required to cause hormone-like actions. Opioid analgesia during anesthesia may have prevented major sympathoadrenal stress responses. A positive correlation between IX4 and MAP has been reported (9). This was also seen in our study. PRA may have a more important role in regulating hemodynamics during CPP than is suspected. A release of ADH, previously observed with the CPP technique (1,8,31), was also observed with our retractor method. An increase of ADH is multifactorial. Surgery induces high concentrations of ADH for several days (32). The main physiological role of ADH is to regulate diuresis after changes in serum osmolality (32). Our patients were given a similar volume loading with isoosmolar fluids. A positive correlation between ADH and MAP has been documented (31) but was not confirmed by our study. The clinical impact of ADH remains still unresolved in this setting.

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ANESTH VS CO,

Tympanic membrane temperature decreased, on average, by 0.5”C during CPP with room temperature gas insufflation. No cooling was seen with the retractor method. Four patients in the CPP group suffered from shivering. Shivering after intraoperative cooling increases oxygen consumption up to 40%-50% (12). Together with increased PRA and NE concentrations, cooling may have a harmful effect on renal blood flow. Currently, gasless laparoscopic cholecystectomy is not widely accepted because the surgical view is not obtained without experience (13). In our study, a distended colon and intraabdominal obesity limited the surgical view when the retractor was used. Thus, operation times were somewhat longer, although our surgeon is an experienced laparoscopist. Laparoscopic procedures have been considered especially beneficial for high-risk patients, because recovery is faster than that after an open technique (33). However, laparoscopy with CO, insufflation has been associated with serious adverse effects in patients with cardiopulmonary diseases (34,35). Deterioration in urine output and renal oxygen balance caused by CPP may also be harmful to patients with borderline renal function and those with a transplanted kidney. CPP can be considered safe to use with ASA physical status I or II patients.

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Y,

II

“,