Opioid analgesics

Opioid analgesics cause strong psychological dependence. Physical dependence is manifested by the withdrawal syndrome of autonomic storm and CNS irritability. A strong tolerance for these drugs and a cross tolerance with other drugs of the same classification of opioid analgesics develop. Studies indicate that in people who are chronically addicted to opioid analgesics such as morphine, the minimum alveolar concentration of inhalation anesthetics (see Chapter 20) is increased, which indicates that a cross tolerance with general inhalation anesthetics may exist.^7,8

Heroin, an opioid analgesic that is derived from morphine, is degraded in the body to morphine approximately 30 minutes after injection. The most common problem associated with the use of heroin and other opioid analgesics is pulmonary edema; other dysfunctions include superficial bacterial infections, adrenal insufficiency, bacterial endocarditis, liver disease, urinary abnormalities (proteinuria and glycosuria), and false-positive serology. In addition, approximately 30% of the persons dependent on opiates have positive results on the Venereal Disease Research Laboratory test for syphilis, but approximately 25% of these results are true positive when checked with the Treponema immobilization test.

Perianesthesia nursing care of a patient who is dependent on an opiate, such as heroin dependency, focuses on monitoring the patient for complications.³ Monitoring for the withdrawal (abstinence) syndrome is the foremost concern. The abstinence syndrome after dependence on an opiate occurs in two phases. The acute phase occurs during the first few days. The protracted phase, which is not readily treatable, can persist for as long as 2 to 6 months. The acute opiate abstinence phase is not dangerous to life because it usually is not associated with convulsions and delirium. Instead, the symptoms are anxiety, nervousness, jittery behavior, anorexia, rhinorrhea, hypotension, muscle twitching, insomnia, sweating, pupillary dilation, gooseflesh, nausea, and vomiting. Symptoms during the protracted phase include those of the acute phase, along with convulsions and delirium. Treatment for the acute opiate abstinence phase is accomplished with any opioid analgesic; reports indicate that clonidine has proved to be most effective in attenuating the symptoms. New research indicates that dexmedetomidine may also be effective in attenuating the symptoms. Treatment for the protracted phase focuses on protection of the patient and abatement of the symptoms shown by the patient. If a patient is suspected of dependence on an opiate, opioid antagonists such as naloxone (Narcan) should not be administered because the withdrawal syndrome can be precipitated. No attempt should be made at withdrawal of the patient who is actively dependent on an opiate during the postanesthesia care unit (PACU) period. Liberal use of morphine or methadone in the PACU appears to be satisfactory. Patients who are formerly dependent on opioids should not receive opioids; analgesics such as pentazocine (Talwin) and butorphanol (Stadol) should be used in their place. Nonsteroidal antiinflammatory drugs may also be considered in a multimodal approach for these patients.⁶

General central nervous system depressants

The patient dependent on a barbiturate may appear only nervous and anxious before surgery; however, the patient should be monitored after surgery for anxiety, tremors, and hallucinations. These symptoms usually develop on the second or third postoperative day and can be treated with a barbiturate until acute illness has passed. These patients also appear to have an increased tolerance to anesthesia and therefore have an increased chance of anesthetic toxicity.

The dependency rate of persons taking benzodiazepine compounds has increased significantly during the last decade. The benzodiazepine drug is usually taken in combination with marijuana or alcohol to obtain a high. Chronic intoxication has been reported with the use of these compounds. The benzodiazepine that produces the most dependency is diazepam (Valium); however, midazolam (Versed) will soon rank at the same level as diazepam. These drugs are becoming popular because of their rapid onset of action coupled with their pleasure-giving effects. The pharmacologic effects of the benzodiazepines are similar to those of the barbiturates.⁹ This classification of drugs is somewhat addictive and includes withdrawal syndromes.

For treatment of mild to moderate overdoses of benzodiazepines, the drug physostigmine in an adult dosage of 1 to 2 mg given intravenously can be used. Flumazenil (Romazicon), is a true benzodiazepine receptor antagonist with longer action and fewer side effects. The usual adult dose is 0.1 to 0.2 mg given intravenously. As with naloxone for patient dependence on an opioid, flumazenil must be used with caution with patients who are benzodiazepine dependent. More specifically, reversal of benzodiazepine dependence is associated with precipitating the withdrawal syndrome, including seizures (see Chapter 21).

Alcoholism has long been widespread, but it is difficult to define. An alcoholic, for the purposes of this discussion, is a person who is excessively dependent on alcohol and who has developed a noticeable degree of mental, physical, psychologic, or pathologic disorders. Alcohol was the first anesthetic; it can produce anesthesia, respiratory depression, and hypotension. Alcoholic dependency has been linked to complications during the perianesthesia phase including alcohol withdrawal syndrome, increased infections, acute respiratory distress syndrome, cardiovascular complications, and secondary hemorrhage.⁶

Alcohol affects many of the body’s major systems.¹⁰ Cirrhosis of the liver is common in the later stages of alcoholism. This knowledge is of importance to the perianesthesia nurse because the liver detoxifies many drugs administered during the perioperative period (see Chapter 16). Hepatic cirrhosis can produce significant alterations in pulmonary and cardiovascular functions. Hyperventilation and arterial oxygen desaturation are common findings caused by an increase in shunting of blood away from areas in the lung where diffusion of oxygen occurs. Concomitant with this is an increase in blood volume that can lead to cardiac hypertrophy and eventually to congestive heart failure. Fluid balance is affected by the presence of alcohol, because alcohol exhibits antidiuretic effects by inhibiting the release of antidiuretic hormone. Alcoholic cirrhosis (Laënnec’s cirrhosis) is also associated with portal vein hypertension, renal failure, hypoglycemia, duodenal ulcer, esophageal varices, and hepatic encephalopathy.

The alcoholic, in comparison with the nonalcoholic, usually requires a larger amount of sodium thiopental for induction and a higher concentration of anesthetic agents during surgery. Prediction of the time or the character of emergence from anesthesia is difficult in the alcoholic patient. This patient may be anxious and may have a stormy emergence and postoperative phase.

During the PACU phase, the alcoholic patient should be monitored for withdrawal symptoms. The minor alcohol withdrawal syndrome is characterized by symptoms such as tremulousness, insomnia, and irritability. Because of autonomic nervous system imbalance, signs such as tachycardia, hypertension, and cardiac dysrhythmias are often observed. The minor alcohol withdrawal syndrome can occur within 6 to 8 hours after abstinence by the alcoholic patient. The signs and symptoms of this syndrome usually disappear within 48 hours without treatment.

In approximately 5% of the alcoholic population, the severe alcohol withdrawal syndrome, or delirium tremens, occurs with abrupt cessation of alcohol ingestion. The mortality rate from this syndrome is approximately 15%; it is considered a medical emergency. The time of onset of delirium tremens is 48 to 72 hours after the abrupt discontinuation of alcohol ingestion.¹¹

The patient is difficult to manage if withdrawal symptoms are allowed to develop. The severe withdrawal syndrome should be suspected if symptoms occur, such as restlessness, disorientation, tremulousness, and hallucinations. In addition, because of activation of the sympathetic nervous system, symptoms such as diaphoresis, hyperpyrexia, tachycardia, and hypertension are seen. When any of these symptoms are observed, hypoxia should first be ruled out because the symptoms of withdrawal can be confused with those of hypoxia. The treatment used to control the withdrawal symptoms is sedation with diazepam, along with intravenous fluids and electrolytes, vitamin replacement (i.e., thiamine), and glucose. If deemed necessary by the attending physician, propranolol may be given to suppress the clinical manifestations of the increased sympathetic nervous system activity. If cardiac dysrhythmias occur, lidocaine can be administered intravenously.

Central nervous system sympathomimetics

Cocaine has a two-pronged effect—vasoconstriction and mood alteration—because it inhibits the reuptake of catecholamines.^9,12 The mood-altering effect is similar to the psychological effect produced by amphetamines. Cocaine is steadily becoming one of the most popular drugs among persons dependent on a substance. Patients who are known to be dependent on cocaine should be closely monitored in the PACU for hypertension and cardiac arrhythmias. These patients are prone to nosebleeds, and care should be taken in giving nursing care near or directly to the nose and nasal cavity.

CNS stimulants, which include amphetamines, are becoming extremely popular with the teenage population; they tend to have the pharmacologic effect of long-acting vasopressors. The patient has dilated pupils, tachycardia, palpitations, cardiac arrhythmias, and changes in temperature regulation and appears to be extremely anxious. If the stimulant is wearing off, the patient is lethargic and depressed. Continuous electrocardiographic monitoring for cardiac arrhythmias is necessary and is coupled with frequent blood pressure and pulse measurements. The mental sensorium should also be monitored throughout the patient’s stay in the PACU.

Cannabinoids

The hemp plants, for which cannabis is the generic name, contain approximately 30 active substances that are called cannabinoids. Of these, tetrahydrocannabinol (THC) is the most active. Marijuana is the generic term applied to the hemp plants. The marijuana cigarette contains rolled or crushed dried leaves from the hemp plant. Each marijuana cigarette contains approximately 0.005 g of THC. The cannabinoids are threefold more potent when inhaled than when ingested orally. Psychological changes occur minutes after inhalation of marijuana, and the effects peak in 1 hour for as long as 3 hours.³

The peripheral effects of THC on the autonomic nervous system include vagal blockade and beta-adrenergic stimulation. The person dependent on marijuana has tachycardia, peripheral vascular dilation, bronchodilation, conjunctival congestion, and a dry mouth. The actual effects of THC on the CNS are not known.¹³

Because of the rapid effects of the drug, along with the short duration of action and the absence of physiologic dysfunction or changes, patients dependent on marijuana do not seem to present any added problems in the PACU. Because of the chronic irritation produced by the inhalation of smoke from the marijuana cigarette, chronic dependence should be monitored for chronic bronchitis.

Psychedelics

Phencyclidine is the hallucinogen most commonly used today. This drug is a popular veterinary anesthetic agent (Sernylan) and is related pharmacologically to the drug ketamine. It can be ingested, taken parenterally, or inhaled. The sensory effects have a rapid onset and last approximately 1 to 2 hours, and the CNS effects can last for 1 or more days. The CNS activation usually produces sympathetic nervous system activation.¹⁴

The perianesthesia nurse is unlikely to have much contact with a patient under the influence of this drug. If a patient who is dependent on this drug should require perianesthesia care, the nurse must monitor this patient for sympathetic activation; symptoms such as dilated pupils, increased pulse, and elevated blood pressure should be reported immediately to the attending physician.

LSD is a hallucinogen that reached its peak of use in the late 1960s and remained popular through in the 1990s. This drug is ingested orally, and its major effects occur in a dose-related manner. Moderate doses of the drug cause euphoria, marked sensory distortion (including heightened awareness of sensory stimuli), and occasional visual hallucinations. Large doses of LSD usually lead to frightening hallucinations and a distorted body image, commonly known as a bad trip. This drug also produces some hypertension, dilated pupils, and increased temperature, by virtue of its stimulation of the central hypothalamic area of the brain. The onset of the psychologic effects of LSD is after approximately 40 minutes, and the duration is approximately 2 hours. Some of the milder effects of LSD have been reported to last as long as 8 hours after ingestion.

The primary focus of perianesthesia nursing care for the patient who is in the hallucinogenic state is to prevent self injury and sedation. The bad trip effects can be managed with a phenothiazine or benzodiazepine such as diazepam. Other considerations in regard to the patient who has ingested LSD are that the analgesic effects of opioids are potentiated by LSD and that the plasma cholinesterases are somewhat inhibited by LSD. Opioid dosage may need to be reduced in these patients, and if succinylcholine is to be administered to the patient, the possibility of prolonged apnea exists (see Chapter 23).

Inhalants

Inhalants can make a person extremely dependent and consist of breathable chemical vapors that produce mind-altering effects. Persons who use inhalants can have significant dependence; they are likely to be teenage people because the drugs are easily accessible and inexpensive.^14,15 Inhalants are classified into three categories: solvents, gases, and nitrates.

The solvents consist of paint thinners or solvents, electronic contact cleaners, and felt-tip marker fluid. The gases consist of such household products and commercial products as butane lighters and propane tanks, whipping cream aerosols, spray paints, hair or deodorant sprays, and fabric protector sprays. Gases used for anesthetic medical purposes, such as isoflurane, sevoflurane, desflurane, and nitrous oxide (see Chapter 20), are now being used illicitly and can cause dependency.¹⁶ The nitrates—such as cyclohexyl nitrite and butyl nitrite, which are available to the public, and amyl nitrite, which is only available by prescription—are now used as substances that can produce dependency.

The inhalants that cause dependency produce effects that are similar to the inhalational anesthetics as described in Chapter 20. Basically, these inhalants cause an intoxicating effect when they are inhaled through the nose or mouth into the lungs. When inhaled in high concentrations, these inhalants can induce heart failure and even death. Some of the irreversible effects of these inhalants can include hearing loss, peripheral neuropathies or limb spasms, central nervous system damage, and bone marrow damage. Some of the serious yet potentially reversible effects include hemoglobin oxygen depletion and liver or kidney damage.¹⁷

The implications in the perianesthesia care of a patient who is using inhalants can be great. Given the fact that these substances can cause reversible and irreversible effects, each patient should be evaluated individually for use of these drugs. Health care professionals who care for these patients should remember that these inhalants are mainly used by children, with the highest usage between grades 6 and 12, and that usage continues to be a significant problem among youths. For perianesthesia nursing, the deliberate misuse of these volatile substances poses a significant risk or considerable morbidity and mortality in the adolescent population in the PACU. All these inhalants basically cause severe dysfunction to the liver and cause it to be unable to detoxify most drugs used in anesthesia. Consequently, even small doses of opioid or nonopioid drugs have a prolonged length of action. Should the perianesthesia nurse suspect that a patient is dependent on inhalants, the anesthesia care provider must be advised because an entirely new regime of pain relief care has to be developed. Certainly, the lowest dose of any opioid or nonopioid should be considered, and the perianesthesia nurse should monitor for signs of cardiovascular and respiratory depression.

Club drugs

Club drugs are most popular in the teenage and young adult population who are part of the nightclub, bar, rave, or trance scenes. Raves and trance parties are usually nightlong events that include adolescents who might not use the specific drugs; however, those who do are attracted to the use of these rather low-cost agents that appear to produce increased stamina and intoxicating highs. Research now shows that these drugs can change critical parts of the brain. Because of the different effects on the E-C coupling mechanisms of muscles as opposed to skeletal muscle relaxants (see Chapter 23), these agents are not implicated in malignant hyperthermia (see Chapter 53).

3,4-Methylenedioxymethamphetamine (MDMA, or ecstasy) is a psychoactive drug that has both stimulant (amphetamine-like) and hallucinogenic (LSD-like) properties. This drug has many street names such as ecstasy, Adam, XTC, hug, beans, and love drug. MDMA has many routes of administration, including oral, rectal, intravenous, or inhalation.¹⁸

The problems associated with MDMA are similar to those found with the use of amphetamines and cocaine, which were discussed previously. The psychological difficulties may include such phenomena as confusion, depression, sleep problems, severe anxiety, and paranoia. The physical difficulties include such things as muscle tension, involuntary teeth clenching, nausea, blurred vision, faintness, and chills or sweating. Physiologic concerns are that this category of drugs can cause hypertension and tachycardia, and long-term use can result in damage to the brain in the parts that focus on thought, memory, and pleasure.

Research on the effects of MDMA on the patient recovering from anesthesia continues to be desperately needed. The reader is encouraged to review the effects of cocaine because the pharmacologic actions are similar, and consequently the effects of the MDMA category of drugs on emergence from anesthesia could be significant, resembling the emergence of the patient with cocaine dependence.

Date rape drugs

Gamma hydroxybutyrate (GHB) is a euphoric, sedative, and anabolic. It is a widely used drug that was obtained over the counter in health food stores until 1992. It has street names of liquid ecstasy, soap, easy lay, and Georgia home boy. Coma and seizures can occur after the use of GHB. Combined with alcohol, GHB can cause nausea and dyspnea. GHB has been associated with poisonings, overdoses, date rapes, and deaths. This drug has a short duration of action and is not easily detectable on routine hospital toxicology screening tests. Research needs to be conducted on this drug to determine its long-term effects, and actual dependency has not been established.

Flunitrazepam (Rohypnol) is a benzodiazepine that when mixed with alcohol incapacitates victims and prevents them from resisting sexual assault. This drug, like midazolam, produces anterograde amnesia. This drug is not approved for use in the United States and its importation is illegal. The street names for this drug include rophies, roofies, roach, and rope, and its illegal use continues to be a problem in the border states, particularly Texas and Arizona.

Ketamine is an intravenous anesthetic drug (see Chapter 21) that is used illegally in the club and rave scenes and has been used as a date rape drug. It can be injected or snorted and is known on the street as special K or vitamin K. This drug produces a dreamlike state and hallucinations.¹⁸ In high doses, ketamine causes delirium, amnesia, impaired motor function, high blood pressure, depression, and apnea. The veterinary form of this drug appears to create the most dependency; its frequency of use is steadily increasing.

Care of the substance abuse patient in the postanesthesia care unit

The use of illicit drugs has become a national issue, particularly in the health care arena. It is even a greater issue for the health care providers in the perianesthesia nursing setting. The recreational drugs, such as alcohol, along with the many other illicit drugs such as cannabis, “crack,” LSD, cocaine, and amphetamines present a significant challenge to the PACU nurse. Many of these patients that abuse drugs can have a “normal” anesthetic experience and then experience acute drug withdrawal in the PACU. If a patient exhibits increased blood pressure, tachycardia, abdominal cramping, irritability, tremors, diarrhea, or sweating, acute drug withdrawal should be suspected. The patient should be examined for the signs and symptoms as described in Table 52-2. After the evaluation is performed, the PACU nurse should notify the attending physician or anesthetist to facilitate the appropriate intervention. The treatment should be symptom oriented, and use of scoring systems to determine treatment approach is becoming more prevalent.⁶ In addition, the emergency drugs and equipment should be placed at the patient’s bedside. Other interventions will probably include a blood sample and a urine sample to aid in the identification of the specific drug in question.

Table 53-2 Initial Patient Evaluation for Suspected Substance Abuse

Adapted from Nagelhout J, Plaus K: Nurse anesthesia, ed 4, St. Louis, 2010, Saunders.

Summary

Substance dependence in the United States is increasing at an alarming rate. All ages and people from all walks of life are affected by this problem. This chapter provides evidence that a person can become dependent on a variety of formulations. Even more serious is the number of practitioners on the anesthesia care team who are becoming dependent on drugs that may be readily available.

Health care practitioners must recognize the severity of the addiction trends among subsets of health care professions.⁴ It is important to learn to recognize, report, and prevent this continued escalation of drug dependence. The key feature is that all must agree that early intervention may save the lives of colleagues and fellow practitioners. Probably the most difficult abuse issue that has become of national epidemic is the abuse of prescription drugs. This problem presents the PACU nurse with a variety of signs and symptoms that are difficult to explain or justify. However, if the patient demonstrates abnormal physiologic function, prescription drug abuse should be considered.

The intent of this chapter was to provide the reader with an overview of the many drugs and substances that can be used by a person to become dependent. Not all the drugs and substances were identified or discussed because this area is ever changing. The key point presented was the overview of how the perianesthesia practitioner should modify the PACU nursing care with regard to patients who are dependent on a drug or substance category presented. Armed with this knowledge, the outcomes of the perianesthesia patient are enhanced. Certainly the use of illicit drugs is an ever increasing public health issue. In the PACU, drug withdrawal can and does occur. Identification of the specific abused drug is essential, and rapid intervention can be life saving for this type of patient.