KEEPING WATCH

KEEPING WATCH
MONITORING IS CRITICAL TO THE PATIENT OUTCOME PROCESS 

By Kathy Dix

Before the advent of modern technology, patients were monitored with good old-fashioned blood pressure cuffs and manual pulse checks. But current advances in medicine allow for pulse oximetry, end-tidal CO2 monitoring, electrocardiograms (EKG) and even temperature monitoring for hypothermia associated with surgery. Most of the professional organizations representing anesthesiology have issued their own recommendations for what constitutes clinical best practices when monitoring a patient’s vital signs and other indicators of normal pre-, peri-, and postsurgical health.

These recommendations are similar across the industry, whether it addresses physicians or nursing staff, and many of the recommendations mirror those for inpatient facilities. For example, the American Society of Post Anesthesia Nurses (ASPAN) says that its standards of care are prepared for perianesthesia nurses throughout the country, whether they’re providing the same care in an inpatient or outpatient setting. They require that patients be monitored continuously during their emerging phases of anesthesia, no matter where the anesthesia is provided. Their recommendations include continuous cardiac monitoring, pulse oximetry, frequent vital signs and temperature monitoring.

In its Standards and Checklist for Ambulatory Surgery Facilities, the American Association for Accreditation of Ambulatory Surgery Facilities (AAAASF) says, “All recovering patients must remain under direct observation and supervision by appropriately trained medical personnel until discharged from monitored patient care.” This requires that “a physician, certified registered nurse anesthetist (CRNA), or registered nurse (RN) with advanced cardiac life support (ACLS) certification or who is otherwise qualified in resuscitation is immediately available until all patients have met the criteria for discharge from the surgical facility.”

The standards also demand that a separate pulse oximeter be available for each patient in the recovery room. Not only that, but there should be a recovery room record maintained that includes vital signs, sensorium, medications, nurse’s notes, and other relevant information, and post-operative vital signs should be recorded at suitable intervals until the patient is discharged from the facility.

The standards specify what patient monitoring should include when the patient is undergoing anesthesia. They state, “Patient monitoring during anesthesia will consist of:

Oxygenation — Assessed by O2 analyzer if an anesthesia machine is used during general anesthesia, which also includes an alarm for low O2 concentration.

Pulse oximetry — Adequate illumination, which should be available to assess patient color.

Ventilation — Clinical signs are evaluated by continual observation during regional/sedation analgesic.

Circulation — Circulation must be monitored by one or several of the following:

• Continuous EKG during the procedure 
• Arterial blood pressure every five minutes (minimum) 
• Heart rate every five minutes (minimum) 
• Pulse oximetry 
• Heart auscultation 
• Intra-arterial pressure 
• Ultrasound peripheral pulse monitors puke plethysmography or oximetry 

Temperature — Temperatures should be monitored when clinically significant changes in body temperature are intended, suspected or anticipated.”

Donna E. Habich, public relations manager for the American Society of Anesthesiologists (ASA), references recommendations from that association. In its Guideline for Ambulatory Anesthesia and Surgery, the society points out, “These are minimal guidelines which may be exceeded at any time based on the judgment of the involved anesthesia personnel. These guidelines encourage high-quality patient care, but observing them cannot guarantee any specific patient outcome.”¹

It is necessary that the ambulatory surgery center (ASC) follow these minimal recommendations, but also supplement them if need be with more extensive monitoring of the patient. In the society’s Guidelines for Office-Based Anesthesia, which it considers a subset of ambulatory anesthesia, the ASA says, “All equipment should be maintained, tested and inspected according to the manufacturer’s specifications.

Back-up power sufficient to ensure patient protection in the event of an emergency should be available. In any location in which anesthesia is administered, there should be appropriate anesthesia apparatus and equipment which allow monitoring consistent with ASA “Standards for Basic Anesthetic Monitoring” and documentation of regular preventive maintenance as recommended by the manufacturer.”²

In its Standards for Basic Anesthetic Monitoring, the society cautions, “appropriate use of the described monitoring methods may fail to detect untoward clinical developments.”

During the administration of all anesthetics, the patient’s oxygenation, ventilation, circulation and temperature should be continually evaluated, the society says, because it is essential to ensure adequate oxygen concentration in the inspired gas and the blood during all anesthetics.

There is more than one way to monitor oxygenation -- inspired gas and blood oxygenation may both be used. With inspired gas, when the patient is under general anesthesia, oxygen concentration should be measured with an oxygen analyzer that has a low oxygen concentration limit alarm. With blood oxygenation, regardless of the type of anesthetic, there should be a quantitative method of assessing oxygenation such as pulse oximetry.

If pulse oximetry is the monitor of choice, it is essential to make the alarm audible to the anesthesiologist. Of note, pulse oximetry can be made more difficult if the patient is shaking, or if there is low profusion.

Ventilation must also be assured, using qualitative signs such as chest excursion, observation of the reservoir breathing bag and auscultation of breath sounds. And, the society recommends, “Continual monitoring for the presence of expired carbon dioxide shall be performed unless invalidated by the nature of the patient, procedure or equipment. Quantitative monitoring of the volume of expired gas is strongly encouraged.”

Thus, end-tidal CO2 monitoring is required, not optional, unless there is a reason why it cannot or should not be used.

“Continual end-tidal carbon dioxide analysis, in use from the time of endotracheal tube/ laryngeal mask placement, until extubation/ removal or initiating transfer to a postoperative care location, shall be performed using a quantitative method such as capnography, capnometry or mass spectroscopy,” and “when ventilation is controlled by a mechanical ventilator, there shall be in continuous use a device that is capable of detecting disconnection of components of the breathing system,” they state.

It is important to note that capnography and capnometry are two different means of monitoring. According to the American Association for Respiratory Care (AARC) clinical practice guideline, Capnography/Capnometry During Mechanical Ventilation, “Although the terms capnography and capnometry are sometimes considered synonymous, capnometry suggests measurement (i.e., analysis alone) without a continuous written record or waveform. For the purposes of this guideline, capnography refers to the evaluation of the CO2 in the respiratory gases of mechanically ventilated patients. A capnographic device incorporates one of two types of analyzers: mainstream or sidestream.

Mainstream analyzers insert a sampling window into the ventilator circuit for measurement of CO2, whereas a side-stream analyzer aspirates gas from the ventilator circuit, and the analysis occurs away from the ventilator circuit. Analyzers utilize infrared, mass or Raman spectra, or a photoacoustic spectra technology.”³

For monitoring the patient’s circulation, the ASA recommends that every patient undergoing anesthesia have a continuously displayed EKG from the initiation of anesthesia until the patient leaves the anesthetizing location. These patients should all have arterial blood pressure and heart rate evaluated at least every five minutes, and should also have a continual evaluation of circulatory function by one of the following methods: pulse palpation, auscultation of heart sounds, monitoring of a tracing of intra-arterial pressure, ultrasound peripheral pulse monitoring, or pulse plethysmography or oximetry.

Body temperature is another crucial factor to monitor. Patients may be prone to malignant hyperthermia (which is rare) or to hypothermia, which is much more common.

The Malignant Hyperthermia Association of the United States (MHAUS) offers this description of the disorder: “Malignant hyperthermia (MH) is a silent, inherited metabolic disorder of muscle. Affected individuals usually appear perfectly normal and have no functional difficulties in everyday life. However, when these individuals are given a triggering anesthetic, this silent disorder may turn deadly. MH is ‘triggered’ by specific general anesthetics. Preoperative evaluation and screening of those at risk, as well as prompt intraoperative detection of MH by the signs (increased carbon dioxide excretion, muscle rigidity and fever), together with prompt treatment with dantrolene sodium, will eliminate mortality almost entirely.”⁴

The association adds, “Dantrolene prophylaxis is not recommended for most MH-susceptible patients. Dantrolene can worsen muscle weakness in patients with muscle disease and should be used with caution. For most procedures, including those requiring general anesthesia, dantrolene prophylaxis may be omitted, provided non-triggering anesthetics are used, there is appropriate monitoring, and an adequate supply of dantrolene is available.”

A full supply of dantrolene should be stocked on-site -- 36 vials -- even if potent volatile agents are not used, and succinylcholine is available for resuscitation. However, MHAUS recommends, “If neither potent volatile agents nor succinylcholine are used or available, dantrolene need not be present.”⁵

An MH cart should include dantrolene, sterile water (without a bacteriostatic agent) to reconstitute dantrolene, sodium bicarbonate, furosemide, dextrose, calcium chloride, regular insulin (refrigerated), and antiarrhythmics.

The certain drugs known to trigger MH include succinylcholine and the potent inhalational agents (sevoflurane, desflurane, isoflurane, halothane, enflurane). Older inhalational anesthetics such as ether, cyclopropane and methoxyflurane can also serve as triggers.

However, local, regional, and monitored anesthesia care appear to be safe. And, MHAUS adds, “Spinal, epidural and nerve block anesthesia utilize local anesthetics, and such techniques are safe to use in MH susceptibles. Intravenous drugs are safe, including propofol, barbiturates, benzodiazepines, and etomidate. Nitrous oxide is safe.”

Hypothermia is also a concern. Maintaining patient temperature during a procedure can be difficult, especially when the temperature of the operating room is typically lower than the standard “room temperature.” Some surgeons even lower the temperature of the OR for personal comfort of the medical staff, which can increase the chance of hypothermia in the surgical patient.

Carol Peterson, RN, MAOM, CNOR, regularly responds to questions of perioperative nurses in the journal of the Association of periOperative Registered Nurses (AORN). In response to a nurse who cited this problem, Peterson responded, “AORN and the Centers for Disease Control and Prevention (CDC) support the American Institute of Architects’ Academy of Architecture’s recommendation that OR temperature be maintained between 68 degrees F and 73 degrees F. Negative consequences for patients who experience hypothermia during a surgical procedure may include adverse myocardial events, impaired platelet functions and coagulopathy, reduced medication metabolism, shivering, discomfort, impaired wound healing, and increased risk of surgical site infection. All patients undergoing a surgical procedure, no matter how minor, are at risk, to varying degrees, of developing hypothermia.”⁶

She continues, “The growing body of research regarding hypothermia demonstrates reduced incidence of postoperative surgical site infections when patient warming is begun in the preoperative holding area. Many institutions use warming devices intraoperatively and postoperatively, but they are seldom used preoperatively. The evidence in this study indicating that preoperative warming for at least 30 minutes before surgery reduces postoperative surgical site infections is compelling. Warming patients preoperatively helps prevent unplanned hypothermia and decreases the incidence of wound infections postoperatively. Maintaining a patient’s temperature is a key component of safe patient care.”

New advances in monitoring allow data from a monitor to be converted into a format that is compatible with electronic medical records (EMRs), so it is not necessary to manually input these figures into the patient’s record.

One of these systems is the Acuity LT Central Monitoring System from WelchAllyn®. It can record patient data for up to 24 hours, and provide a printed record for files if necessary.

Eastman Kodak Company’s Dental Systems group and Criticare Systems, Inc., have developed a software package that enables oral surgeons to automatically record and store patients’ vital signs during surgery. Criticare patient monitoring solutions has been integrated with Kodak WINOMS CS Practice Management Software, permitting the software to automatically record heart rate, blood pressure, temperature and respiration in an electronic anesthesia record.

A non-invasive blood pressure monitoring device can allow anesthesiologists to quickly monitor and measure blood pressure variations. The Tensys T-Line has been designed to be clinically equiv to an arterial line, but uses a transdermal pressure sensor to continuously measure blood pressure at the radial artery.

Accurate medication infusion can also be monitored, as seen in Cardinal Health’s Alaris® Network, which provides wireless connectivity to the Alaris System, a modular point-of-care platform that integrates infusion, patient monitoring and clinical best practice guidelines for optimal outcomes at the point of care. It allows the real-time capture of medication infusion, patient monitoring and continuous quality improvement data from these devices.

Another type of monitoring that has gained in popularity has been bispectral index monitoring (BIS). This evaluation of intraoperative awareness has received a great deal of press attention over the past few years, as patients have reported being awake during surgery and have been able to accurately report conversations of the surgical staff during the procedure.

A study published in 2004 demonstrated that “awareness with recall,” as they name it, occurs in the U.S. at a rate between one to two cases per 1,000 patients receiving general anesthesia.

Awareness with recall occurs when patients do not receive enough anesthesia to remain unconscious. As a result, they may be awake during surgery, aware of what is happening and retain memory of this experience after the surgery is over. Studies show that awareness can be a traumatic experience for patients and result in the development of long-term psychological problems.⁷

The result of this study, and others like it, is that many facilities are adopting BIS to help guide anesthesia personnel in proper dosing to ensure that the patient is “out.” The occurrence is uncommon, but so horrifying that in many healthcare facilities, the approximate cost of $5.55 per patient is considered well worth it, considering that the monitoring also provides for decreased drug use and increased efficiency.

A BIS monitor interprets data from an electroencephalogram (EEG) into a number that indicates the patient’s level of consciousness. The “BIS value” ranges from 100 (full awareness/ wakefulness) to zero (no brain activity). Patient monitoring is not only used during the procedure, but also before and after the surgery.

Baseline vital statistics are taken before the patient is given anesthesia. In recovery, patients are monitored with EKG, pulse oximetry, and blood pressure. In the step-down unit, monitoring generally ceases, unless there is a reason to monitor the patient more carefully. A final set of vitals is taken before discharge.

The American Association of Nurse Anesthetists (AANA) has published a position paper on unintended awareness during general anesthesia.

The position statement identifies the possible causes of awareness, and recommends that every anesthetizing location develop a defined written policy that includes the following practices:

• Assessing patient risk for awareness prior to surgery and anesthesia 
• Ensuring proper function of anesthesia equipment 
• Developing an anesthesia care plan that includes appropriate pharmacologic agents, anesthesia techniques and patient monitoring techniques to reduce risk of awareness 
• Considering brain function monitoring in situations where awareness risk is increased 
• Conducting patient assessments post-surgery to identify and manage possible occurrences of awareness.⁸

The position statement notes that use of brain function monitors along with other patient monitoring modalities has been shown to reduce patient risk of awareness. However, not all brain monitors have been studied for their effectiveness in reducing the incidence of awareness. Because of this, individual facilities should consider clinical evidence when selecting brain monitors for use to reduce risk of awareness.

Other monitoring may not be as essential, but can provide valuable feedback to healthcare providers. One device is useful to orthopedic surgeons, as it utilizes nanotechnology to monitor the healing of hip implants. A self-powered wireless microsensor for monitoring the bone healing process after surgery was created by engineers from the University of Alberta. The device may even reduce the wait time for patients needing artififcial joint implants, according to Walied Moussa, a professor in the university’s department of mechanical engineering.

According to a press release issued by the university, the monitor measures how well the bone grows and attaches to the surface of the implant, which creates better xation and joint stability — or osseo-integration. The implant measures that osseointegration. It uses the natural movement of the patient’s body as its power source, and remains dormant until a doctor asks it to transmit data.

The device will also cut down the need for X-rays to monitor bone functionality, reducing costs and exposure to radiation, and can detect and identify bone loss before it is even visible on a radiograph. It will not only monitor bone healing at the time of surgery but also can determine when implants are worn out and need to be replaced.