Management Of Hysteroscopic Surgery Complications
Donna M. Morrison
The article “Management of hysteroscopic surgery complications” is the basis for this AORN Journal independent study. The behavioral objectives and examination for this program were prepared by Helen Starbuck Pashley, RN, MA, CNOR, with consultation from Trish O’Neill, RN, MN, education coordinator, Center for Perioperative Education.
A minimum score of 70% on the multiple-choice examination is necessary to earn three contact hours for this independent study. Participants receive feedback on incorrect answers. Each applicant who successfully completes this study will receive a certificate of completion. The deadline for submitting this study is Feb 29, 2000.
Send the completed application form, multiple-choice examination, learner evaluation, and appropriate fee to
AORN Customer Service c/o Home Study Program 2170 S Parker Rd, Suite 300 Denver, CO 80231-5711
Or fax with a credit card number to (303) 750-3212
After reading and studying the article on the management of hysteroscopic surgery complications, the nurse will be able to
(1) identify the complications of hysteroscopic surgery,
(2) describe how these complications occur, and
(3) discuss how the complications of hysteroscopic surgery can be prevented.
Hysteroscopic surgery has become a routine gynecologic procedure, performed in the OR as well as in office settings. The widespread use of hysteroscopic surgery makes understanding the significance of patient monitoring and proper equipment operation essential. Patient monitoring and proper equipment use are perhaps the most effective methods to prevent intraoperative complications and ensure positive patient outcomes.
Hysteroscopic surgery is considered a safe procedure; however, complications do occur, and they can be severe and rapid. The surgical team members must be able to recognize adverse patient response early so intervention to minimize morbidity and mortality can begin. Hyponatremic encephalopathy, uterine perforation, hemorrhage, and infection are considered the four major complications of hysteroscopic surgery,(1) Most complications that develop are associated with intravasation of distending media.(2)
Intravasation of distending media into the body’s vascular system can occur when the patient’s intrauterine pressure exceeds mean arterial pressure.
Intrauterine pressure is the single most important variable the surgeon can
control to prevent intravasation. A value greater than the mean arterial
pressure significantly increases the risk of intravasation.(3)
Other factors that influence intravasation are the type of procedure and length of surgery.(4) Procedures that open numerous vascular channels create many avenues for the medium to enter the vascular system. In addition, longer procedures can increase the risk of intravasation resulting from increased exposure of the distending medium to open vascular channels.
The potential for intravasation is higher during an operative hysteroscopy; however, it can occur during diagnostic hysteroscopy as well. Intravasation can occur with any distending medium. Carbon dioxide, for example, is a very safe medium when used under proper conditions. It is the only gas medium approved for hysteroscopic procedures.(5) Carbon dioxide is quickly absorbed by the blood, and it is released rapidly during pulmonary ventilation. The risk of intravasation, therefore, is low. Embolization of [CO.sub.2] can occur, even when the endometrium is intact, when intrauterine pressures exceed too mm Hg and flow rates exceed 100 mL/L.(6) A small amount of [CO.sub.2] gas embolization is a recognized risk of diagnostic hysteroscopy, and is not considered dangerous. It occurs in 52% of patients undergoing hysteroscopy with [CO.sub.2] distention and is frequently seen when instillation pressures range from 60 mm Hg to 120 mm Hg.(7) Pressures between 30 mm Hg and 120 mm Hg are normal pressures needed to adequately distend the uterus. Normal flow rates for [CO.sub.2] range between 40 mL/L and 60 mL/L. An increase in the patient’s partial pressure of [CO.sub.2] (p[CO.sub.2]) and a decrease in the patient’s partial pressure of Oxygen (p[O.sub.2]) may indicate that excessive amounts of [CO.sub.2] have intravasated. An increase in p[CO.sub.2] and a decrease in p[O.sub.2] result in metabolic acidosis and cardiac irregularity. Any change in the patient’s cardiac rhythm should be immediately assessed when [CO.sub.2] is used as a distending medium.
Excessive distention pressures or flow rates (ie, pressures that exceed 200 mm Hg and flow rates that exceed 150 mL/L) may cause large volumes of [CO.sub.2] to be intravasated. This can result in metabolic changes, embolization, and death. In one clinical study, each case in which significant complications from [CO.sub.2] instillation developed, excessive [CO.sub.2] pressures and/or flow rates were the cause. In this study it was also noted that equipment often was used that was not designed for hysteroscopy.(8) To reduce the risk of intravasation of [CO.sub.2], the surgeon must keep pressures and flow rates to a minimum, and the perioperative nurse should ensure that only correct equipment and instrumentation that is checked regularly for accuracy and proper function is used for hysteroscopic surgery.(9)
Equipment safety precautions. To make hysteroscopic surgery as safe as possible for the patient, [CO.sub.2] should only be instilled with devices specifically designed for hysteroscopic use. These devices maintain intrauterine pressure below 200 mm Hg with either constant preset pressures and variable flow rates or constant preset flow rates with variable pressures. It is important that laparoscopic insufflators never be used for hysteroscopy. These insufflators deliver [CO.sub.2] at a rate of at least 1 L/minute. The intravasation of gas that occurs from these high pressures and flow rates can cause irreversible brain damage or death. Equipment calibrations must also be accurate to prevent gas intravasation due to increased flow rates and pressures. Higher pressures and flow rates can be delivered if equipment is miscalibrated or malfunctions.
Clinical causes of intravasation. Intravasation air embolization can occur when uterine veins are open during surgery and the air pressure is greater than venous pressure.(10) Although this does not happen often, it is a complication that must be considered when operative hysteroscopy is performed. Trendelenburg position is also a factor that increases the risk of air embolization. When the patient is in Trendelenburg position, the uterus is elevated above the heart, which may cause alterations in air pressure and venous pressure. Trendelenburg position may be a greater risk when the patient is breathing spontaneously.(11) Attempts should be made to position the patient in as little Trendelenburg as possible, especially if she is awake.
Bubbles in inflow tubing or bubbles created by gases that form during the procedure may also increase the risk of intravasation air embolization. Flushing inflow tubing before use and careful manipulation of the hysteroscope and instruments by the surgeon can minimize these risk factors. In addition, devices that use gas as a coolant and can introduce gas into the uterus, such as coaxial neodymium:yttrium-aluminum-garnet (Nd:YAG) laser fibers (with or without sapphire tips), should not be used during surgical procedures. When gas is used with these fibers, the high flow rate delivered does not adjust to variations in intrauterine pressures, which can result in serious injury or death. Therefore, fluid should be used as the external coolant for coaxial fibers.
Combined surgeries (eg, laparoscopy with hysteroscopy), patients with a history of previous surgery or intrauterine disease, and exposure of the dilated cervix to room air have been reported as factors that may increase the risk of air embolization. Using methods to decrease exposure of the cervix to room air can minimize these risk factors. For example, removing the vaginal speculum after the hysteroscope is inserted into the uterus or using a syringe to occlude the open end of intrauterine devices used for uterine manipulation are techniques that can be used to prevent air embolization.
Patients usually do not survive the initial insult of large amounts of air in the vascular system; therefore, when intravasation air embolism occurs, it is an emergency. Early therapy of an air embolism is crucial. If excessive [CO.sub.2] intravasation is suspected, the surgical team members must immediately stop the procedure, place the patient on mechanical ventilation (if she is not already intubated and ventilated), and begin pulmonary and vascular support measures. If significant embolization has occurred with accumulation of undissolved [CO.sub.2] in the right side of the heart, team members should turn the patient on her left side. This maneuver may increase blood flow.(12) If the patient survives the initial event, she is treated with hyperbaric oxygen. Hyperbaric consultation can be obtained at no cost 24 hours a day through the Divers Alert Network, Duke University, Durham, NC (919) 684-8111.(13)
The more common and equally serious complication of hysteroscopic surgery–dilutional hyponatremia–is associated with intravasation of a low viscosity nonelectrolytic distending medium. Due to the severity and incidence of dilutional hyponatremia, the remaining focus of this discussion will be on its physiology, early detection through patient monitoring, and patient management when it occurs.
Unrecognized and untreated dilutional hyponatremia results in hyponatremic encephalopathy, a condition with high morbidity and mortality rates. The management of intravasation of instilled intrauterine fluid is imperative in the prevention of dilutional hyponatremia. Intraoperative monitoring of intrauterine fluid absorption is the most important intervention that can be made to ensure positive patient outcomes. It is important, therefore, to understand the physiology of dilutional hyponatremia, the role sodium plays in the cellular movement of water, how the use of electrolyte-free solutions affect this movement, and how this affects the patient.
THE PHYSIOLOGY OF BODY FLUIDS
Approximately 60% of a typical adult’s weight consists of fluid that is separated into extracellular and intracellular fluid compartments. The extracellular fluid compartment is further divided into intravascular (ie, plasma) and interstitial fluid compartments. Fluid found in these compartments is made up of water and electrolytes (ie, any compound that separates into ions when dissolved in water and that is able to conduct electricity). If the ion is positively charged, it is called a cation; if it is negatively charged, the ion is called an anion. The ions formed when electrolytes dissolve have important functions in the body. These ions
* control the osmosis of water between body compartments,
* help maintain the acid-base balance required for normal cellular activities,
* allow production of action potentials and graded potentials through the electrical current they carry,
* control secretion of some hormones and neurotransmitters, and
* are cofactors that are needed for optimal activity of enzymes.(14)
An important electrolyte related to hysteroscopic surgery is the sodium cation. This electrolyte controls osmosis of water between body compartments and plays an important role in development of acute hyponatremia.
The cation sodium. Sodium is the most abundant extracellular ion. Approximately 90% of extracellular cations are sodium ions. These cations are very important in controlling electrolyte balance because of the role they play in fluid osmolality (ie, the concentration of solute in a solution). All body fluids have the same water concentration, and both extracellular and intracellular fluids have equal solute concentrations, even though the composition of their solutes differs. This allows water to move freely across cell walls.
Sodium accounts for almost half of the osmolality of extracellular fluid, while potassium (the most abundant cation of intracellular fluid) is responsible for maintaining fluid volume within cells. Fluid osmolality refers to the ability of solute in solution to separate water molecules so that a solution with a high solute concentration has a low water concentration.(15) The concentration of electrolytes is usually measured in the plasma, because interstitial fluid is essentially the same as plasma and special techniques are required to measure intracellular fluid. Plasma osmolality, therefore, reflects the osmolality of all body fluids.(16)
Movement of substances. Materials within the body are transported and exchanged between body cells and the outside world (ie, during respiration) via the blood. Interstitial fluid is the medium used for exchanges between intracellular fluid and blood plasma. Substances move between plasma and interstitial fluid across capillary walls. Substances enter and leave capillaries in three ways:
* vesicular transport,
* diffusion, and
* bulk flow (ie, filtration and reabsorption).
Most substances in blood or interstitial fluid cross capillary walls by diffusion (ie, the process that accounts for the largest part of capillary exchange in most body tissues). The exception to this is in the brain, where the blood-brain barrier blocks diffusion of many substances to protect it from harmful substances and pathogens. Substances that cross the blood-brain barrier are either soluble lipids or are water-soluble substances that receive assistance from a transporter to carry them across by active transport. Water is an example of a substance that passes rapidly into brain cells; sodium is a substance that enters slowly.
The movement of sodium by diffusion is also inhibited through the action of the sodium-potassium pump, also referred to as the sodium pump (Figure 1). The sodium pump, located in cell membranes, is an active transport mechanism that regulates the passage of sodium and potassium in and out of cells. Active transport is the movement of material across the membrane of a cell by means of chemical activity that allows the cell to admit larger molecules than would otherwise be able to enter.(17) In the presence of adenosine triphosphate (ATP), sodium is actively moved from the cell to extracellular fluid, and potassium is actively pumped into the cell. During active transport, material that normally would not be able to cross cell membranes is allowed to cross by chemical interaction. Certain enzymes (eg, adenosine triphosphatase [ATPase]), play a role in active transport, providing a chemical pump that helps move substances through the cell membrane.(18)
[Figure 1 ILLUSTRATION OMITTED]
The sodium pump also influences the irritability of nerves and muscles, because sodium is an important factor in nerve conduction. A nerve membrane has a positive charge outside and a negative charge inside the cell when it is in a relaxed or resting stage. When the membrane becomes more permeable, a small number of potassium ions move out of the cell, as a large number of sodium ion moves into the cell. The membrane then becomes polarized. This means the outside of that portion of the membrane is now negatively charged. The depolarization is transmitted along the nerve cell. The depolarization wave produced is called the nerve impulse. Repolarization immediately follows polarization, and re-establishes the resting stage. The electrolyte change causes the nerve to conduct electrical impulses to the muscle and causes the muscle to contract. Sodium, therefore, influences the irritability of muscles, valves, and the heart. Any disturbance in sodium balance can disturb synchronization of neuromuscular function.(19)
Hormones and fluid balance. Aldosterone, antidiuretic hormone (ADH), and atrial natriuretic peptide (ANP) control sodium levels in blood. Aldosterone is secreted by the cortex of the adrenal glands and acts on the distal convoluted tubes and collecting ducts of the nephrons of the kidneys, causing them to increase their reabsorption of sodium. As sodium moves from the filtrate (produced in the glomerulus of the kidney) back into the blood, it establishes an osmotic gradient. This causes water to follow sodium from the filtrate back into the blood. Aldosterone is secreted in response to reduced blood volume or cardiac output, decreased extracellular sodium concentration, and increased extracellular potassium concentration. When the blood concentration of sodium drops below 135 mEq/L, the posterior pituitary gland stops the flow of ADH. The lack of ADH allows increased excretion of water in the urine, which returns sodium to normal levels in the extracellular fluid.
An increase in atrial pressure also inhibits the release of ADH, whereas a decrease in atrial pressure stimulates its release. The atria of the heart also produce the hormone ANP, which increases sodium and water excretion by the kidneys when the body’s sodium level is too high. Osmoreceptors, located in the hypothalamus and liver, sense alterations in body fluid osmolality and stimulate the kidney to add or remove water from urine to make it isotonic with plasma. This mechanism is referred to as free-water clearance.
Osmosis. Osmosis determines concentrations of body fluids and is driven by osmotic pressure. Osmotic pressure is the pressure that develops when two solutions of different concentrations are separated by a semipermeable membrane. During osmosis, water moves from an area with low solute concentration (ie, high water concentration and lower osmotic pressure) to an area with high solute concentration (ie, low water concentration and higher osmotic pressures).
Fluid tonicity. Tonicity refers to the effect a fluid has on cellular volume.(20) Tonicity also affects the normal shape of a cell. Isotonic solutions (ie, solutions in which cells or tissues maintain a normal state without undergoing lysis or crenation) maintain the normal shape of red blood cells, whereas a hypotonic solution (ie, a solution having an osmotic pressure greater than that of physiologic salt solution or any other solution being used as a standard) will cause cells to swell because water molecules enter cells faster than they leave. A hypertonic solution causes water to move out of cells faster than they enter, causing cells to shrink. Fluid that is hypotonic has a decreased concentration of solutes. Hypotonicity occurs when body fluids are excessively dilute and when more electrolyte-free water is taken in than is excreted.
Osmolality. Tonicity and osmolality have different effects on fluid. Fluid may have hyperosmolality without having hypertonicity, however, fluid that has hypo-osmolality is always hypotonic.(21) The increased tonicity of the interstitial fluid causes water to move from plasma into interstitial fluid. As the water enters cells, they become hypotonic and swell, leading to hyponatremia. Osmoregulation (ie, the mechanism for maintaining a normal cell volume) regulates body fluid tonicity. Osmoregulators (eg, ADH), are cell volume receptors that are located in the anterior hypothalamus outside the blood-brain barrier. They respond to changes in tonicity by providing afferent inputs to the control systems that regulate water intake and excretion. When these systems fail to maintain body fluid tonicity, cells must adapt to the disturbance to preserve their volume.
Intracellular fluid and interstitial fluid normally have the same osmotic pressures. A fluid imbalance between these two compartments can be caused by a change in their osmotic pressures. Most often, an osmotic pressure change is due to a change in the concentration of sodium outside cells or the concentration of potassium inside cells. The dilution of body fluids causes sodium concentrations to fall below the normal range. This results in a decrease of osmotic pressure in interstitial fluid and makes that fluid hypotonic. Water from the hypotonic interstitial fluid moves into intracellular fluid in an effort to regain equilibrium. As the water moves from interstitial fluid to intracellular fluid, the tonicity of the interstitial fluid increases, and the tonicity of intracellular fluid decreases.
SODIUM CONCENTRATION AND HYPONATREMIA
When speaking of hyponatremia, the change in osmolality and tonicity of fluid and cells must be considered. The decreased concentration of sodium in extracellular fluid causes the change in osmotic pressure and osmolality of the fluid. This change affects the tonicity of the cell, thereby affecting cell permeability.
Body weight, sex, and age must also be considered when examining the effect changes in serum sodium concentration have on the body. Normal body water content varies between individuals depending on body weight, age, and sex. This is due to variations in body fat content, because fat contains little water. Women have more body fat than men and elderly women generally have less body fat than young women do. In young women, body water content is approximately 50% of body weight, and in elderly women it accounts for approximately 40%.(22) Small, elderly women, therefore, are very susceptible to large changes in serum sodium concentration.
Women are at greater risk of developing hyponatremia than men, and premenopausal women are at greater risk of increased morbidity and mortality from hyponatremia than postmenopausal women are. Premenopausal women appear to be more susceptible to hyponatremic encephalopathy than postmenopausal women, possibly due to inhibition of sodium-potassium ATPase by female sex hormones. Progesterone and progesterone derivatives can inhibit sodium-potassium ATPase release in tissue. It has also been reported that premenopausal women are 26 times more likely to suffer permanent brain damage or die from hyponatremic encephalopathy than postmenopausal women.(23) In preparing premenopausal women for hysteroscopic surgery, gynecologists often administer a gonadotropin-releasing hormone (GnRH) agonist to decrease the risk of hyponatremic encephalopathy by creating a postmenopausal state. Some literature suggests that pretreatment with GnRH agonist should become a standard of care for hysteroscopic surgery because premenopausal women are at high risk for death or permanent brain damage from even modest postoperative hyponatremia (ie, serum sodium level 120 mmO/L to 132 mmO/L).(24)
Total concentrations of solute in solutions used during hysteroscopic surgery also affect dilutional hyponatremia. Solutions are categorized according to their electrolyte concentration. If the sum of sodium and potassium exceeds 150 mEq/L, the solution is considered hypertonic. If the cation concentration is less than this the solution is considered to be hypotonic. Isotonic solutions are solutions that have the same concentrations of water molecules and solutes on both sides of the cell membrane. It has been suggested that a hypotonic solution should be thought of as an isotonic solution that has been diluted with water.
In dilutional hyponatremia, the concentration of sodium is changed due to a rapid influx of a nonelectrolytic fluid, which increases the circulation of free water. Nonelectrolytic solutions are used during hysteroscopic surgery when monopolar electrosurgery is used. When free water enters the vascular system through blood vessels and sinuses opened as the integrity of the endometrial lining is interrupted during surgery, free water decreases the concentration of serum sodium, decreases tonicity, and increases cell permeability. Normal serum sodium is 135 mEq/L to 142 mEq/L. Dilutional hyponatremia occurs when serum sodium levels fall below 130 mEq/L as a result of excessive intravasation of low viscosity fluids over a short period of time.
Symptoms of dilutional hyponatremia. Dilutional hyponatremia is characterized by changes in the patient’s mental status first, followed by changes in vital signs. The first symptom a patient experiences is apprehension, followed by disorientation, irritability, twitching, nausea, vomiting, and shortness of breath. As dilutional hyponatremia progresses, the patient experiences signs of impending pulmonary edema (eg, moist skin and mucous membranes, pitting edema, polyuria, dilute urine, pulmonary tales). These symptoms are seen when serum sodium ranges between 125 and 130 mEq/L (Table 1). With advancement of dilutional hyponatremia and impending pulmonary edema, the patient experiences changes in vital signs. The patient becomes tachycardic and hypertensive initially, and her respirations increase. As the hyponatremia increases, the patient becomes bradycardic and hypotensive. At serum sodium ranges of 120 and 125 mEq/L she may be anemic and cyanotic, with further changes in mental status. Serum sodium below the level of 120 mEq/L, is considered severe hyponatremia and can result in hyponatremic encephalopathy. Symptoms of severe hyponatremia include
* congestive heart failure,
* muscular twitching,
* focal weakness,
* convulsions (which may lead to coma), and
SIGNS AND SYMPTOMS OF HYPONATREMIA
Mild Mild to moderate
(sodium < 130 mEq) (sodium 125 to 130 mEq)
Apprehension Moist skin
Disorientation Moist mucous membranes
Irritability Pitting edema
Nausea Dilute urine
Vomiting Pulmonary rales
Shortness of breath
Mild Moderate to severe
(sodium < 130 mEq) (sodium < 120 to 125 mEq)
Vomiting Changes in mental status
Shortness of breath
(sodium < 130 mEq) (sodium < 120 mEq)
Apprehension Congestive heart failure
Twitching Muscular twitching
Nausea Focal weakness
Vomiting Visual disturbances/
Shortness of breath (due to glycine
when sodium is
< 115 mEq)
Hyponatremic encephalopathy. This is the result of an osmotic imbalance between extracellular fluid and brain cells, which leads to movement of water into the brain and results in cerebral edema? It is the end result of unrecognized and untreated dilutional hyponatremia and is characterized by decreased body temperature, decreased oxygen saturation, and seizures or dilated pupils (ie, signs that indicate increased intracranial pressure).
The blood-brain barrier (which is selectively permeable to ions and other solutes but is freely permeable to water) allows extremely rapid water movement into or out of the brain. Changes in brain sodium content begin almost immediately after a change in plasma tonicity and may be quite substantial.(26) Brain tissue and plasma is osmotically equal under normal circumstances; however, when there is a rapid change in serum sodium concentration, brain cells do not have time to adapt to this change. Water is osmotically drawn into the brain from the plasma, expanding its extracellular and intracellular volume. The persistent swelling of the brain exerts pressure against the skull, which leads to the neurological symptoms and can lead to pressure necrosis of the brain. When brain volume expands by more than approximately 5%, cerebral herniation will occur if this state is not corrected through appropriate treatment.(27) Brain stem herniation develops when the brain expands in its attempt to equalize interstitial and intravascular osmotic pressures (Figure 2). This phenomenon occurs when serum sodium falls below 115 mEq/L.
[Figure 2 ILLUSTRATION OMITTED]
Hysteroscopic solutions and hyponatremia. The risk of cerebral edema (ie, hyponatremic encephalopathy) is influenced by the type of distending medium used during hysteroscopic surgery and its osmolality. The most common solutions used for operative hysteroscopy, when monopolar electrosurgery is used, are 1.5% glycine and 3% sorbital. The patient’s serum osmolality is normally 285 mOsm/L; 1.5% glycine has an osmolality of 200 mOsm/L, and 3% sorbitol has an osmolality of 178 mOsm/L. The lower osmolality of these fluids increases the risk of fluid shifts from the extracellular to intracellular compartment of cells in the brain. Sorbitol is metabolized to [CO.sup.2] and water, and glycine is metabolized to ammonia. Glycine and sorbitol leave behind free water after metabolism. Absorption and metabolism of glycine may also increase blood concentrations of ammonia, which also affects serum sodium concentrations. Increased blood ammonia concentrations are characterized by persistent postoperative nausea and vomiting.
MANAGEMENT OF FLUID INTRAVASATION
Managing complications of hysteroscopic surgery begins preoperatively. The perioperative nurse should perform a thorough preoperative assessment to determine a baseline status for the patient. Factors to include in the preoperative assessment are the patient’s age, if pretreated with a GnRH agonist, and her preoperative sodium levels. This information should be found in the patient’s chart. These factors help isolate intravasation risk factors as they relate to each patient. The perioperative team members then are able to develop a specific patient care plan. The surgical procedure is also important. Any procedure that will open a large number of vascular channels (eg, resectoscopic myomectomy, endometrial ablation, resection of uterine septum, lysis of intrauterine adhesions) should be considered a procedure at high risk for intravasation. For example, perioperative team members would need to take additional precautions for a 26-year-old patient scheduled for a resection of a submucous fibroid who presents with a baseline sodium of 135 mEq/L, and who has not been pretreated with a GnRH agonist. This patient should be considered at high risk for intravasation.
Each member of the perioperative team (ie, surgeons, anesthesia personnel, nursing personnel) plays an important role in the prevention and management of hysteroscopic complications. The surgeon must be experienced in hysteroscopic surgery, understand the principles of fluid management and its complications, and have knowledge of electrosurgery and other methods to control bleeding.(28) The surgeon should also know proper assembly and use of equipment and instruments, and employ good surgical technique. The anesthesia personnel must also understand the principles of fluid management and its complications and assume responsibility for the patient’s hemodynamic and respiratory status during the procedure. The scrub person is responsible for ensuring necessary instruments are working properly and readily available, and the circulating nurse assists the anesthesia care provider and ensures that equipment is in proper working condition and is used correctly.
The most important nursing responsibility during hysteroscopic surgery, however, is accurate measurement of intrauterine fluid intake and output. A patient who is awake during the procedure and who becomes anxious alerts team members to a possible decrease in serum sodium. Team members can evaluate the patient and treat her before further adverse response occurs. Hysteroscopic surgery, however, is frequently performed with general anesthesia, and the patient is unable to convey distress. A large intrauterine fluid deficit, therefore, may be the first indication team members have that excessive intravasation has occurred, and may have caused a decrease in serum sodium.
Significance of monitoring fluid absorption. Intraoperative monitoring of intrauterine fluid intake and output is the most effective method for prevention and management of complications from excessive intravasation. Total body weight, total body serum sodium concentration (measured in mEq), and the total amount of fluid absorbed is used by the clinician to determine the amount of free water excess in the body or the sodium deficit. The information obtained is used to plan appropriate treatment if needed. Accurate measurement of the amount of intrauterine fluid the patient receives, and the amount of fluid returned, is the quickest way to detect possible intravasation (Figure
[Figure 3 ILLUSTRATION OMITTED]
The objective of monitoring fluid absorption during hysteroscopic surgery is to identify decreases in serum sodium concentration before it has adverse effects on the brain. Significant fluid intravasation can occur through venous channels and sinuses opened when the integrity of the endometrium is disrupted during hysteroscopic surgery. This can occur in a very short period of time, can result in a very rapid changes in serum sodium, and can result in severe dilutional hyponatremia and encephalopathy. The most accurate indicator of changes in serum sodium is ongoing measurement of serum sodium concentration; however, this is not convenient, cost-effective, or always necessary when fluid absorption can be monitored. Accurate measurement of intrauterine fluid absorption is the first line of defense. It enables the team members to correct problems early, thus decreasing morbidity and mortality. Casual and inaccurate measurements of fluid intake and output can result in very serious complications that can lead to irreversible brain damage and death.
The objective when taking intrauterine fluid measurements is for the perioperative nurse to determine fluid deficits so fluid absorption can be calculated. It is important for the perioperative team members to channel all escaping fluid into a container where the circulating nurse and the surgical team members can measure it. This makes proper draping important. Normally, the surgeon positions the patient to facilitate unrestricted movement of the hysteroscope and his or her ability to see. The surgeon also drapes the patient to provide a sterile field and to facilitate collection of intrauterine fluid. Fluid that cannot be collected cannot be measured, which increases the chance of inaccurate monitoring.
The perioperative team members determine if fluid deficits exist by measuring the amount of fluid the surgeon instills into the uterus and the amount of fluid returned to the fluid collecting receptacle from the outflow sheath of the hysteroscope, where it can be measured. The circulating nurse should assess fluid amounts at least every 15 minutes and report the results to the surgeon and anesthesia care provider after each assessment. Fluid limits usually range from 500 mL to 1,500 mL, and surgical time is usually limited to one hour. Some researchers suggests that nursing personnel monitor intake and output every five minutes and that anesthesia personnel obtain a serum sodium level when deficits greater than 500 mL are discovered. Other researchers suggest that anesthesia personnel draw serum sodium level after surgical time reaches 30 minutes. In addition, anesthesia personnel are encouraged to keep IV fluids running at a “keep open” rate so the patient will not receive an abundance of IV fluid in addition to that received by intrauterine instillation.
Whenever nursing personnel or the surgeon note a discrepancy in fluid absorption, the surgeon should stop infusion of the distending medium, and the circulating nurse should reassess the patient’s intake and output. Anesthesia personnel should draw serum sodium levels if a determination of absorption cannot accurately be made. Fluid discrepancies can arise from large amounts of “unmeasurable” loss (ie, fluid spilled on the floor or absorbed by the sheets under the patient) or from miscalculation. Careful patient positioning and draping help decrease the chance of unmeasurable losses. Care when counting fluid intake and output also decreases the chance for miscalculation. In addition, a decrease in outflow also facilitates accurate fluid measurements. By closing both the inflow and outflow channels of the hysteroscope, the surgeon can obtain more accuracy in monitoring fluids because it is difficult to accurately measure fluid instilled and returned if this process continues while measurements are taken.
When intravasation does occur, it should be treated as an emergency. The surgeon should stop the procedure as soon as it is safe for the patient, and measures to facilitate excretion of excess fluid should begin. This includes measuring electrolytes and the administration of IV furosemide. The surgeon should insert a Foley catheter, if one is not present already, to monitor the patient’s diuresis. Anesthesia personnel should maintain the patient on high levels of oxygen. If elevation of the patient’s serum sodium does not occur from diuresis, anesthesia personnel can administer a 3% sodium chloride solution IV. The goals of therapy for acute hyponatremia are to reduce water in the brain and to increase sodium concentration in the extracellular fluid as necessary to maintain normal respiration and keep the patient seizure-free and alert. The total correction of acute hyponatremia should take place over 48 hours.(29)
Hysteroscopic policies and procedures. Interdepartmental policies for patient monitoring during hysteroscopic surgery should be developed after researching recommendations in the literature. When developed, these policies and procedures should be followed carefully. In consultation with the members of the gynecology, anesthesiology, and nursing departments, parameters for the frequency of intake and output measurements, absorption limits, and time limits should be developed. An intake and output record for hysteroscopic surgery should also be developed and included as a part of the medical record.
Our first responsibility to our patients as healthcare professionals is to do no harm. Determining whether our patients are being harmed, is an obligation we must take very seriously. Complications of hysteroscopic surgery are infrequent; however, the severity of these complications can cause permanent alterations in the lifestyle of the patient and those around her. Monitoring intrauterine fluid intake and output is is the quickest means available to determine if the patient is experiencing an adverse response to intrauterine fluid instilled. Each member of the perioperative team has different responsibilities in patient monitoring and prevention of complications. The combined efforts of team members facilitates safe patient care.
(1.) J E Carter, “Hysteroscopic surgery–aemic encephalopathy,” Minimally Invasive Therapy and Allied Technology 6 (1997) 249-248.
(2.) F D Loffer, “Complications of hysteroscopy–their cause, prevention, and correction,” Journal of the American Association of Gynecologic Laparoscopists 3 (November 1995) 11-26.
(14.) G J Tortora, S R Grabowski, eds, “Fluid, electrolyte and acid-base hemostasis,” in Principles of Anatomy and Physiology, eighth ed (New York: Harper Collins Publishers, Inc, 1996) 895.
(15.) R H Stems, A Spital, “Disorders of water balance,” in Fluid and Electrolyte Balance, second ed, J P Kokko, R L Tannen, eds (Philadelphia: W B Saunders Co, 1990) 140.
(16.) N M Metheny, ed, “Fundamental concepts and definitions,” in Fluid and Electrolyte Balance: Nursing considerations (Philadelphia: J B Lippincott Co, 1996) 3-10.
(19.) V R Street, C A B Lee, C A Barrett, eds, “Sodium,” in Fluids and Electrolytes–A Practical Approach, third ed (Philadelphia: F A Davis Co, 1984) 71.
(20.) Ibid; Stems, Spiral, “Disorders of water balance,” 160.
(22.) Ibid, 143.
(23.) Ibid; Carter, “Hysteroscopic surgery–avoid complications of hyponatremic encephalophathy,” 7.
(25.) Ibid, 8.
(26.) Ibid; Sterns, Spiral, “Disorders of water balance,” 160.
(27.) Ibid; Carter, “Hysteroscopic surgery–avoid complications of hyponatremic encephalophathy,” 8.
(28.) Ibid, 2.
(29.) Ibid, 8.
Alpern, R J; Saxton, C R; Seldin, D W. “Clinical interpretation of laboratory values.” In Fluid and Electrolytes, second ed, J P Kokko, R L Tannen, eds,
3-15. Philadelphia: W B Saunders Co, 1990.
Metheny, N M, ed. “Sodium imbalances.” In Fluid and Electrolyte Balance Nursing Considerations. Philadelphia: J B Lippincott Co, 1987, 52-57.
Stroot, V R; Lee, C A B; Barrett C A, eds. “The basics.” In Fluids and Electrolytes–a Practical Approach, third ed. Philadelphia: F A Davis Co, 1984, 3-9.
Stroot, V R; Lee, C A B; Barrett, C A, eds. “Intracellular fluid: Excess and deficit.” In Fluids and Electrolytes A Practical Approach, third ed. Philadelphia: F A Davis Co, 1984, 29-41.
Tortora, G J; Grabowski, S R, eds. “The cellular level of organization.” In Principles of Anatomy and Physiology, eighth ed. New York: Harper Collins Publishers, Inc, 1996, 53-63.
Tortora, G J; Grabowski, S R, eds. “Fluid, electrolyte and acid-base hemostasis.” In Principles of Anatomy and Physiology, eighth ed. New York: Harper Collins Publishers, Inc, 1996, 891-899.
MANAGEMENT OF HYSTEROSCOPIC SURGERY COMPLICATIONS
1. What are the four major complications of hysteroscopic surgery?
4. uterine perforation
5. hyponatremic encephalopathy
a. 1, 2, 3, and 5
b. 1, 2, 3, and 4
c. 1, 2, 4, and 5
d. 2, 3, 4, and 5
2. Most complications that develop during hysteroscopic surgery are associated with intravasation of distending media.
3. How does intravasation of distending media occur?
a. when mean arterial pressure exceeds uterine pressure
b. when uterine pressure exceeds mean arterial pressure
4. What other factors can influence intravasation?
1. type of procedure
2. length of procedure
3. type of anesthesia
4. type of equipment
a. 1 and 2
b. 2 and 3
c. 3 and 4
d. 1, 2, and 3
5. Hysteroscopic procedures that open numerous vascular channels do not place the patient at increased risk for intravasation.
6. How do longer hysteroscopic procedures increase the risk for intravasation?
a. Longer procedures increase the anesthesia exposure time.
b. Longer procedures increase the distending media/vascular channel exposure time.
c. More distending media has to be used for longer procedures.
d. all of the above
7. Intravasation can occur with any distending media.
8. Carbon dioxide ([CO.sub.2]) embolization can occur even when the patient’s endometrium is intact if intrauterine pressure exceeds certain limits and flow rates are high enough. What are the limits of pressure and the flow rates above which embolization can occur with an intact endometrium?
a. 50 mm Hg/50 mL/L
b. 75 mm Hg/75 mL/L
c. 100 mm Hg/100 mL/L
d. 120 mm Hg/120 mL/L
9. A small amount of [CO.sub.2] embolization is a recognized risk of diagnostic hysteroscopy and is not considered dangerous. In what percent of patients does this occur?
10. An increase in the patient’s partial pressure of [CO.sub.2] (p[CO.sub.2]) and a decrease in the patient’s partial pressure of oxygen (p[O.sub.2]) may indicate what?
b. intravasation of excessive amounts of [CO.sub.2]
c. fluid overload from the distending medium
d. all of the above
11. An increase in p[CO.sub.2], and a decrease in p[O.sub.2], may result in metabolic acidosis and cardiac irregularity.
12. Dramatic changes in the patient’s cardiac rhythm should be immediately assessed when [CO.sub.2] is used as a distending medium
13. What can the perioperative nurse do to reduce the patient’s risk for [CO.sub.2] intravasation?
a. ensure that only correct instruments and equipment are used
b. check for the accuracy and proper function of equipment used
c. all of the above
14. Carbon dioxide should only be instilled with devices designed specifically for hysteroscopic use that maintain intrauterine pressure below 200 mm Hg with either constant preset pressures and variable flow rates or with constant preset flow rates and variable pressures.
15. Why should laparoscopic insufflators never be used for hysteroscopic surgery?
a. The intravasation of gas from these high pressures and flow rates can cause irreversible brain damage or death.
b. These insufflators deliver [CO.sub.2] at a rate of at least 1 L/minute.
c. These insufflators are not designed for use during hysteroscopy
d. all of the above
16. High flow rates and pressures can be delivered unintentionally if the equipment has not be properly calibrated or is malfunctioning.
17. Intravasation can also occur when uterine veins are open and the air pressure is greater than the patient’s venous pressure. What are some of the instances in which this might take place?
a. when the patient is in Trendelenburg position or the dilated cervix is exposed to room air
b. when the patient has a history of previous surgery or intrauterine disease
c. if bubbles are present in the media inflow tubing or if a device that introduces gas into the uterus is used (eg, a neodymium: yttrium-aluminum-garnet [Nd:YAG] laser fiber with or without a sapphire tip)
d. when combined surgeries (eg, laparoscopy with hysteroscopy) are performed
e. all of the above
18. How can the perioperative team members reduce the risk for the intravasation described in question 17?
a. Position the patient in as little Trendelenburg as possible, especially if she is awake.
b. Flush the inflow tubing well to remove bubbles before use.
c. Use fluid to cool coaxial fibers rather than gas.
d. Decrease the exposure of the cervix to room air (eg, remove vaginal speculum after the hysteroscope is inserted, use a syringe to occlude the open end of the intrauterine devices used to manipulate the uterus).
e. all of the above
19. If excessive [CO.sub.2] intravasation is suspected, what must the surgical team members do?
a. stop the procedure
b. mechanically ventilate the patient
c. begin pulmonary and vascular support measures
d. all of the above
20. What are two other measures the team members can take if significant [CO.sub.2] intravasation has occurred?
1. Turn the patient on her left side to increase blood flow.
2. If the patient survives, treat her with hyperbaric oxygen.
3. Begin administering electrolytes and diuretics (eg, furosemide).
4. Monitor fluid intake and output.
a. 1 and 3
b. 1 and 2
c. 3 and 4
d. 2 and 3
21. The more common and serous complication of hysteroscopic surgery is dilutional hyponatremia. This is associated with the intravasation of low-viscosity, nonelectrolytic distending media. What does unrecognized and untreated dilutional hyponatremia result in?
a. fluid overload
b. hyponatremic encephalopathy
c. hypernatremic encephalopathy
22. An important electrolyte related to hysteroscopic surgery is the cation sodium, which controls osmosis of water between body compartments and plays a role in acute hyponatremia.
23. Substances enter and leave capillaries by vesicular transport, diffusion, and bulk flow (ie, filtration and reabsorption). Most substances in the blood or interstitial fluid cross capillary walls by diffusion. The exception to this is the brain, where the — blocks the diffusion of many substances to protect the brain.
c. blood-brain barrier
d. all of the above
24. The sodium pump, located in cell membranes, is a passive transport mechanism regulating the passage of sodium and potassium in and out of cells.
25. Hormones also control sodium levels in the blood. Name two specific hormones that do this.
4. atrial natriuretic peptide
a. 1 and 2
b. 2 and 3
c. 3 and 4
d. 2 and 4
26. Osmosis determines concentrations of body fluids and is driven by osmotic pressure. During osmosis, water moves from an area with low solute concentration to an area with high solute concentration.
27. Tonicity refers to the effect that a fluid has on cellular volume. Tonicity also affects the normal shape of a cell. Isotonic solutions maintain the normal cell shape; what do hypotonic solutions cause cells to do?
28. Osmoregulation regulates body fluid tonicity, and osmoregulators are what?
a. cell volume receptors located in the anterior hypothalamus inside the blood-brain barrier that respond to changes in tonicity by providing efferent inputs to the control systems that regulate water intake and excretion
b. cell volume receptors located in the anterior hypothalamus outside the blood-brain barrier that respond to changes in tonicity by providing afferent inputs to the control systems that regulate water intake and excretion
29. Intracellular fluid and interstitial fluid normally have the same osmotic pressures. Most often, an osmotic pressure change is due to what?
a. a change in the concentration of sodium outside cells
b. a change in the potassium concentration inside cells
c. a dilution of body fluids that causes the sodium concentration to fall below normal range
d. all of the above
30. Normal body water content varies between individuals depending on body weight, age, and sex. What is this due to?
a. variations in body muscle content
b. variations in body fat content
c. all of the above
31. Women are at greater risk of developing hyponatremia than men, and premenopausal women are at greater risk of increased morbidity and mortality from hyponatremia. Why?
a. body fluid levels fluctuate due to the menstrual cycle
b. sodium-potassium adenosine triphosphatase (ATPase) is inhibited by female sex hormones
c. physical changes to the reproductive organs due to aging have not occurred in the premenopausal woman
d. all of the above
32. What does the gynecologist often administer to premenopausal women to prepare them for hysteroscopic surgery and reduce the risk of hyponatremia?
c. gonadotropin-releasing hormone (GnRH) agonist
33. Normal serum sodium is 135 mEq/L to 142 mEq/L. Dilutional hyponatremia occurs when sodium levels fall below 130 mEq/L and is the result of what?
a. excessive intravasation of high-viscosity fluids over a short period of time
b. excessive intravasation of low-viscosity fluid over a short period of time
34. Dilutional hyponatremia is characterized first by changes in the patient’s mental status followed by changes in vital signs. What are some of the first symptoms seen in an awake patient with dilutional hyponatremia?
a. apprehension, disorientation, irritability
b. nausea and vomiting
c. shortness of breath
d. all of the above
35. Symptoms of severe hyponatremic encephalopathy include which of the following?
a. bradycardia, hypotension, congestive heart failure
b. lethargy, confusion
c. muscular twitching, focal weakness
d. convulsions, which may lead to coma and death
e. all of the above
36. Dilutional hyponatremia causes persistent swelling of the brain, which exerts pressure against the skull and leads to the neurological symptoms seen in patients. It can also cause pressure necrosis of the brain. If the hyponatremia is not corrected and the brain volume expands by more than 5%, what can occur?
b. cerebral herniation
d. all of the above
37. Monitoring an awake patient for signs and symptoms of hyponatremia is an appropriate action; however, most hysteroscopic surgery is performed under general anesthesia. What is the first thing the perioperative team members can do to reduce the risk of hyponatremia?
a. monitor the patient’s serum sodium levels
b. monitor the patient’s intrauterine fluid intake and output
c. monitor the patient’s weight
d. administer a GnRH agonist
38.The most accurate indicator of changes in serum sodium is what?
a. ongoing measurement of intrauterine fluid intake and output
b. ongoing measurement of serum sodium concentration
c. all of the above
39. Whenever discrepancies are noted in the fluid absorption, the surgeon should stop the infusion of the distending medium and the circulating nurse should reassess the patient’s intake and output. The anesthesia care provider should draw serum sodium levels if an accurate determination of absorption cannot be made.
40. When intravasation has occurred, it should be treated as an emergency. What steps can the perioperative team members take to correct this?
a. Facilitate the patient’s excretion of excess fluid by the administration of electrolytes and IV furosemide.
b. Insert a Foley catheter to monitor diuresis.
c. Maintain the patient on high levels of oxygen.
d. Administer a 3% sodium chloride solution IV if the patient’s serum sodium levels do not rise from diuresis.
e. all of the above
MANAGEMENT OF HYSTEROSCOPIC SURGERY COMPLICATIONS
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MANAGEMENT OF HYSTEROSCOPIC SURGERY COMPLICATIONS
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Donna M. Morrison, RN, CNOR, is a staff nurse at Northwestern Memorial Hospital Chicago, Ill.
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