Changes in hemostatic mechanisms associated with operative laparoscopy

February 2000, Vol. 7, No. 1 TheJournal of the American Associationof Gynecologic Laparoscopists

Changes in Hemostatic Mechanisms Associated with Operative Laparoscopy Jonathan D. Broome, MRCOG, Vincent R Lamaro, MRANZCOG, and Thierry G. Vancaillie, M.D., FRANZCOG Abstract A 19-year-old woman underwent laparoscopic resection of extensive endometriosis of the cul-de-sac. At completion of surgery the abdomen was deflated for 3 minutes with the patient still in Trendelenburg position, before she was reexamined for intraoperative bleeding. The patient was taken back to surgery 7 hours postoperatively to arrest hemorrhage. (l Am Assoc Gynecol Laparosc 7:(1):149-153, 2000)

were present in both adnexal areas. With a combination of electrosurgery and sharp dissection, diseased peritoneum and rectal serosa were resected (Figure 1), allowing mobilization of the rectum. A rectal probe was not used. Areas of bleeding were identified and coagulated. To assess hemostasis, the abdomen was deflated with the patient maintained in Trendelenburg

The frequency of major complications from laparoscopic surgery is reported to be 0.6% to 2.5%. 1 Hemorrhage accounts for half the complications, ranging from persistent venous oozing to massive blood loss from injury to retroperitoneal vessels. 2 Delayed hemorrhagic complications also occur; the true frequency is unknown but the consequences can be particularly significant in patients undergoing day surgery. Possible reasons for delayed hemorrhage are a bleeding vessel missed at the end of the procedure, effects of pneumoperitoneum, Trendelenberg position, low intraoperative blood pressure, wearing off of vasopressin effect, subacute infection, postoperative analgesia, and bleeding disorders.

Case Report A 19-year-old woman with chronic pelvic pain and dysmenorrhea since menarche underwent elective resection of endometriosis. The disease involved the left pararectal space with deep infiltrating lesions along the lateral wall of the rectum and tethering of the rectum to the left uterosacral ligament. There was also ample evidence of recent acute or subacute pelvic inflammatory disease. Filmy adhesions and hyperemia

FIGURE 1. Laparoscopic excision of endometriosis from the rectal serosa.

From the School of Obstetrics and Gynaecology, University of New South Wales, and Department of Endo-Gynaecology, Royal Hospital for Women, Kensington, Australia (all authors). Address reprint requests to Dr. J. D. Broome, Department of Endo-Gynaecology, Royal Hospital for Women, Barker Street, Randwick, NSW, Australia 2031; fax 02 9382 6758. Accepted for publication on October 6, 1999.

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position. After 3 minutes the abdomen was reinflated and the area of dissection inspected. Blood clots were present over the area of dissection and these were suctioned out. We noted a general ooze but could not identify a specific bleeding point. The operation was concluded and the patient was transferred to the ward. Treatment with broad-spectrum antibiotics was begun intraoperatively. Four hours postoperatively the woman's hemoglobin was 11.6 g/dl. Seven hours postoperatively she began showing signs of active bleeding, with hypotension and tachycardia. The abdomen became visibly distended with signs of peritoneal irritation, and decreased urine output was associated with clinical deterioration. Immediate return to surgery was arranged while initial resuscitation began. Emergency blood count showed a decrease in hemoglobin to 7.3 g/dl. Repeat laparoscopy revealed 2500 ml of blood and clot in the abdomen. This was initially removed by suction and irrigation with the patient in Trendelenburg position. The uterus was held in acute retroversion to tamponade the site of surgery. When the pelvic organs were visualized the uterus was anteverted. Inspection of the area of dissection showed active bleeding from a branch of the median hemorrhoidal (rectal) artery, which was ligated with two endoloops. The median hemorrhoidal artery is a branch of the hypogastric artery and runs in the pararectal gutter above the levator muscles (pubococcygeus; Figure 2). Further suction and irrigation removed remaining

i

blood clots. No further bleeding points were identified. The abdomen was deflated, and reinspection after 5 minutes showed no evidence of continued bleeding. The patient received 5 U blood. She was transferred to the intensive therapy unit overnight. The woman made an uneventful recovery and was discharged home 3 days later. At the first followup visit she was well. The pathology report confirmed the presence of endometriosis as well as an inflammatory process with psammoma bodies. Discussion

Securing adequate hemostasis at completion of any surgical procedure is mandatory. However, the tamponading effect of pneumoperitoneum and reduced venous pressure in the pelvis brought about by Trendelenburg position can lead to bleeding vessels being missed. Textbooks acknowledge this danger and recommend inspecting the operative site either "under low pressure conditions" or with the patient "flat on the table. ''3 Underwater examination without pneumoperitoneum with the patient supine 4 can also be an effective way to assess intraoperative bleeding. Pneumoperitoneum is completely replaced by fluid (Ringer's lactate solution, glycine, normal saline) and vigorously irrigated and suctioned. This may require 10 to 20 L fluid and can be quite tedious. A good view of the pelvis under low-pressure conditions can usually be obtained even with the patient in reverse Trendelenburg position. If using electrolyte-free fluid such as glycine, monopolar electrosurgery can be performed to achieve hemostasis, otherwise bipolar forceps can be used. Accurate fluid balance during the procedure is essential, particularly with electrolyte-free fluids, as the patient may be at risk of developing hyponatremia. In addition to the direct tamponading effect on the venous system, other pathophysiologic effects of pneumoperitoneum and Trendelenburg position must be considered (Table 1).

Temperature General anesthesia, increasing patient age, and coexisting medical conditions all have a deleterious effect on the ability to maintain body temperature? Human studies showed that platelet morphology, platelet aggregation, 6 and endothelial-related coagulation 7 are altered during hypothermia. Laparoscopic gas flow rates over peritoneal surfaces exceed those during laparotomy, and the prolonged nature of some

FIGURE 2. Diagram showing the origin of the median hemorrhoidal artery.

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TABLE 1. Effects of Intraoperative Conditions on Hemostatic Mechanisms

Mean Arterial Pressure

Peripheral Vasoconstriction

Effect on Coagulation Efficiency

Hypothermia Hypercapnea

Increased Increased

Increased Increased

Increased intraabdominal pressure

Increased or unaltered

Increased

Trendelenburg position

Decreased

Decreased

Decreased Variable effects depending on pH May tend toward a procoagulant effect Negligible

laparoscopic procedures exacerbates the problem of heat loss from the patient. Laparoscopic insuffiators use high-pressure bottles as the source of CO2. The change in pressure required to deliver gas to the patient causes gas expansion, with resultant cooling. The higher the gas flow rate, the greater the cooling effect. Attempts were made to warm insuffiated gas, but it had no effect on preventing hypothermia, whereas humidification of insufflated CO2 virtually eliminates the effect of laparoscopically induced hypothermia, s As yet we have no commercially available means of achieving this in our area. The short operating time with most laparoscopic procedures is unlikely to cause significant reduction in patients' core temperature. In prolonged procedures, without appropriate warming devices and in which cold intravenous fluids are administered, susceptible patients are at potential risk for substantial hypothermia and resultant coagulopathy.

Hypercapnea Carbon dioxide is currently the gas most commonly used to achieve pneumoperitoneum because it is nonflammable, inexpensive, and highly diffusable. Systemic absorption of CO2 from the peritoneal surface results in metabolic acidosis, usually compensated for by hyperventilation. Mild metabolic acidosis can cause peripheral vasoconstriction and an increase in heart rate, resulting in an increase in mean blood pressure. 9 Severe metabolic acidosis causes depression of left ventricular function with a resultant decrease in cardiac output and tissue perfusionJ ~ It is unlikely that metabolic acidosis will be allowed to occur with modern anesthesia monitoring. However, transient peripheral vasoconstriction induced by CO2 may mask bleeding from arterioles, especially if baseline mean arterial pressure is low. This theoretical complication

requires observational and experimental confirmation in humans.

Increased lntraabdominal Pressure The mechanical effects of increased intraabdominal pressure and venous compression have been discussed. The decrease in venous return leads to reduced cardiac output with a resultant increase in peripheral vascular resistance.U Mechanical compression of the abdominal aorta, as done in canine experiments, 12 increases sympathetic activity, again resulting in arteriolar constriction. This vasoconstriction induced by higher intraabdominal pressure may make it difficult to detect bleeding points, and emphasizes the importance of reducing pneumoperitoneum when assessing hemostasis. Avulsion of lntraabdominal Adhesions A rare but potentially dangerous complication of pneumoperitoneum is mechanical avulsion of intraabdominal adhesions. Avulsion of perihepatic adhesions at diagnostic laparoscopy resulted in postoperative hemorrhage and laparotomyJ 3

Trendelenburg Position Trendelenburg position of only 15 degrees with insuffiation pressure of 9 mm Hg increased mean arterial pressure by o v e r 2 0 % ) 4 In a study more closely resembling our operating conditions,15 Trendelenburg position of 30 degrees in awake anesthetized patients increased both mean arterial and central venous pressures. This was followed by a secondary rise in both vascular beds after CO2 pneumoperitoneum of 15 mm Hg. Return to the lower preoperative mean arterial and venous pressures occurs at the end of the case when pneumoperitoneum is released and the patient returned to a level position. This is a short interval when the compressive effect of pneumoperitoneum is ceased;

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however, mean arterial and central venous pressures remain elevated. It is also highly likely that the laparoscope has been removed and skin closure commenced. Therefore, reinspection of hemostasis should be performed several minutes after release of pneumoperitoneum and return of the patient to level position.

vented initial bleeding as indicated by a hemoglobin of 11.6 g/dl 4 hours postoperatively. An increase in blood pressure related to postoperative pain and administration of a 100-mg diclofenac suppository (Ciba-Geigy, Pendle Hill, NSW, Australia) may have interfered with clotting mechanisms, leading to uncontrolled intraabdominal hemorrhage. In our practice we now ensure that after completion of any laparoscopic procedure the degree of Trendelenburg position is reduced for 3 minutes while the abdomen is deflated, before reexamining for active bleeding sites. Blood clots present after 3 minutes of low-pressure conditions indicate that hemostasis is not adequate. They should be suctioned out and the area irrigated in an effort to identify a bleeding point. Leaving clots alone in an effort to avoid "stirring up" more bleeding equates to burying one's head in the sand. Occasionally a general ooze from the operative site may be present and may be better left alone, but an initial attempt at identifying a specific bleeding point must be made. This represents a more physiologically correct assessment of hemostasis. In addition, we inquire about patients' blood pressure and exercise caution when the systolic blood pressure is at or below 90 mm Hg. We hope these procedures will help prevent the onset of delayed postoperative bleeding in other women.

Intraoperative Blood Pressure Intraoperative blood pressure has a direct effect on blood flow at the operative site. A low pressure, as in our patient, may give a false impression of hemostasis when checking for bleeding sites. The patient's blood pressure may rise postoperatively in response to painful stimuli, causing a sudden increase in tissue perfusion at the operative site. This may result in postoperative hemorrhage if hemostasis is inadequate. Theoretically a similar effect may be seen after injection of vasopressin to reduce bleeding at the operative site. The elimination half-life of vasopressin is reported to be 10 to 35 minutes. Some operative procedures such as salpingostomy or simple resection of endometriosis may be completed before the drug's vasoconstrictive effect has worn off. If hemostasis is inadequate, delayed hemorrhage may occur.

Postoperative Drugs Insertion of suppositories for postoperative pain relief should be performed with extreme care when a patient has undergone extensive dissection of loose connective tissue. Rupture of blood vessels or disruption of platelet plugs may occur, leading to delayed hemorrhage. The pharmacologic action of some drugs administered postoperatively may cause problems with hemostasis. Antithrombotic agents are obvious candidates, but nonsteroidal antiinflammatory compounds may disrupt platelet aggregation and interfere with clotting mechanisms. In our patient, it is most likely that initial hemostasis with electrofulguration was inadequate. At second laparoscopy an obvious bleeding vessel was seen after the blood clot was evacuated. Hemostasis was achieved by placing a grasping forceps through an endoloop, which was tightened while holding up the bleeding vessel. Other "cold" techniques we could have employed were laparoscopic clips or suturing. Alternatively, the vessel could have been secured by monopolar or bipolar electrosurgery. These "hot" methods were not done because of distortion of normal anatomy from recent surgery and proximity of the rectum. The patient's hemostatic mechanisms pre-

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