Anesthesiologist in cardiac catheterization laboratory; the roles and goals!! A postgraduate educational review [corrected].

It is not uncommon to see in developing and underdeveloped countries, where the anesthesiologist who is untrained in cardiac specialty takes care of cardiac catheterization centers. The service in cardiac catheterization laboratories (CCL) in developed countries and some of the developing countries is mainly provided by the cardiac anesthesiologists. The scenario is not same in some part of developing countries or in underdeveloped countries which are mainly due to increase in number of CCL (catheterization laboratory) when compared to the number of cardiac anesthesiologists working outside the operation theater. It is also important for training the postgraduate in this field as to make them capable and competitive in managing such cases during emergency situation as it may save the life of a patient. Many a times, CCL is built as per the need of cardiologist ignoring the basic needs of cardiac anesthesiologist. It is important to note that anesthesiologist should be competent enough to provide complete, integrated anesthetic care outside the operation theater with available resources. It is challenging for the anesthesiologist to provide sedation or general anesthesia in such critical area where he/she will be dealing with life-threatening situations. In the modern era, the interventional techniques are advancing and treating complex heart diseases is more often. Days are not far where the CCL procedures may reduce the requirement of major surgeries. A careful and dedicated approach by the anesthesiologist with thorough knowledge and skills decreases morbidity and mortality rate. This article helps both cardiac and noncardiac anesthesiologists to improve their knowledge and to approach the patient systematically.

INTRODUCTION

Cardiac catheterization laboratories (CCL) is the place where cardiovascular diagnostic and therapeutic procedures on cardiovascular system are carried out. The first cardiac catheterization on human was performed by Werner Forssmann.[1] A survey showed that there are around thirty million coronary artery disease patients in India, of which 14 million are located in urban and 16 million in rural areas.[2] It is predicted that the number of cases in CCL will keep increasing for both diagnostic and therapeutic procedures. As per reports, the number of CCL is over 172 units in India in 2011.[3] In the past two decades, considerable advances have been developed in interventional cardiology.[4] The service of anesthesiologist does extend to CCL to handle both elective and emergency situations. It is the responsibility of department to train the untrained anesthesiologist for this field.[5] In India, most postgraduate anesthesia programs provide students with only a limited or no exposure to cardiac anesthesia due to unavailability of super specialty set up. Joining a center after completion of postgraduate course, the person may not be confident enough to handle cases in CCL during emergency period. In India, there is a lack of availability of trained cardiac anesthesiologists as the branch itself is becoming unpopular due to the stress involved in it. Hence, there is a serious need to train our postgraduates in such critical areas and build the interest among them.

Anesthesiologists should understand the pathology with which he or she is dealing with and possible physiological changes while administering anesthesia. Priorities for cardiologist may be different from anesthesiologist but a common goal of safety and quality care which will ultimately lead to good outcome. An attempt has been made to deliver the basic knowledge of CCL practices in anesthesiologist point of view through this article, which may help postgraduate students and attending anesthesiologists.

WHY DO WE RECEIVE CALLS FROM CARDIAC CATHETERIZATION LABORATORIES?

The diagnostic and therapeutic procedures are performed on both cardiovascular and noncardiovascular systems. Such procedures may be either elective or emergency and may be life-threatening. In any part of hospital, the emergency service is mainly provided by the anesthesiologist. There are certain procedures such as coronary angiography, peripheral angiography, and angioplasty which requires monitored anesthesia care. Procedures such as device closure in small children may require general anesthesia with controlled ventilation. Certain procedures such as automatic implantable cardioverter-defibrillator placement in adults may require general anesthesia with endotracheal tube in situ. Hence, anesthesiologist plays a vital role in case of CCL procedures.

The elective CCL procedures are considered after the consultation of attending anesthesiologist. This helps to evaluate and investigate the patient for comorbid illness and plan type of anesthesia. During emergency, anesthesiologist helps in securing invasive lines, cardiopulmonary resuscitation, cardioversion, and defibrillation.

SPECIALIST ENCOUNTERED

Although the CCL is mainly operated by the cardiologist, many a times, other specialists such as neurosurgeon (for tumor embolization), interventional pain specialist, interventional radiologist, vascular surgeon, and electrophysiologist utilize the facility for both diagnostic and therapeutic procedures.

THE WORKSPACE FOR ANESTHESIOLOGIST

Workspace is always an issue while working in CCL. Most of the times, the needs of the anesthesiologist in CCL are not considered or options are not sought before constructing the lab. Because of heavy gadgets along with small allotted space, the anesthesiologist may feel claustrophobic. There is always a chance of patient or anesthesiologist getting hurt if unnoticed C-arm of the machine is moved by the technician. Hence, one has to become familiar with the workspace and should be capable to monitor and tackle airway- or hemodynamic-related incidents if it occurs. There are no guidelines or norms for the space that has to be allotted for anesthesia personnel along with workstation. Every country should define and maintain guidelines for workspace of anesthesiologist in CCL.

SAFETY FIRST

Anesthesiologists are also exposed to radiation during fluoroscopy.[6] The adverse effects such as dermal necrosis, cellular mutation, malignancy, infertility, and birth defects are not uncommon. Exposure to radiation is measured by roentgen equivalent man (rem). It is always mandatory that anesthesiologist should enter after wearing lead apron, thyroid shield, and eye protection spectacles as we are near to the source of radiation. It is advisable that there should be dedicated radiation safety equipment for anesthesiologist and the assistant. Attending anesthesiologist should wear a dosimeter for cumulative exposure tracing. Two monitoring badges are mainly recommended by the International Commission on Radiation Protection, one under the lead apron and second on the collar. The recommendation by National Council Radiation Protection and Measurements on maximum exposure of individual (total body) to radiation is 5 rems/year.[7] Centre of Disease Control supports the principle of as low as reasonably possible for radiation exposure.[8] One should try to stand away from the radiation source without compromising patient safety. Working at 80 cm from the isocenter can reduce scattered dose to approximately a quarter of the original dose.[9] Proper positioning of the patient is important, as the fluoroscopy device often limits access to the patient.[10] Proper securing of artificial airway if used, good length of circuit, good length of monitoring cables, and intravenous extensions are necessary to avoid accidental disconnection during C-arm movement.[10]

THINGS TO KEEP READY

All emergency and anesthetic drugs, heparin, protamine, all size syringes, infusion set, infusion pump, intravenous cannula, central venous catheter, defibrillator, arterial catheterization kit, airway instruments and suction apparatus, monitoring devices, and last but not the least, anesthesia workstation should be kept ready. A guide for intravenous drug dosage and common indications is shown in Table 1. Anesthesiologists should be capable to perform advanced cardiac life support as per the latest guidelines whenever required during CCL procedures.

Table 1

Intravenous drug dosages and their common indications

PRE-PROCEDURE EVALUATION

Complete history including birth history (in pediatric cases), treatment history, previous exposure to anesthesia, and physical examinations are mandatory. Most often, the patient posted for CCL procedures will have routine blood investigations, sometimes special investigations such as two-dimensional echocardiography and imaging studies. It is wise to study the investigations and plan the anesthesia accordingly.

FASTING GUIDELINES

Fasting guidelines do not differ, and it remains same for cardiac cases undergoing CCL procedures. Clear liquids are generally considered safe for all patients up to 2 h, breast milk 4 h, and solids up to 6 h before procedure. Avoid dehydration in children, particularly those with cyanotic heart disease. Pediatric and diabetic patients are prone for hypoglycemia. The fasting status may not be adequate in case of emergency procedures and whenever intubation is required, rapid sequence induction and intubation should be considered. Consider intravenous fluids to keep patient euvolemic and euglycemic. Meticulous de airing from syringes and intravenous extensions should be done, especially in case of congenital heart diseases.

MEDICATIONS AND PREMEDICATIONS

Medications are drugs which patient is already taking and advised by the cardiologist or attending physician. Those drugs are usually continued until and unless specified. In patients with diabetes mellitus, it is better to skip morning dose of insulin. Premedications are the one which are advised by the anesthesiologist depending on individual preferences or institutional protocol based. Avoid the premedication drug which interacts with drug which the patient is already consuming. Baseline arterial blood gas and saturation with room air, especially for cyanotic patients, should be performed. Significant blood loss is not noted until and unless complication arises. However, adequate backup is recommended in all the cases.

MONITORING

Routine standard monitors such as pulse oximetry, electrocardiogram, and end-tidal carbon dioxide are done. Most often, the invasive femoral artery and radial artery blood pressure are monitored by the cardiologist. Hypothermia is most common in pediatric patient as thermoregulation is not well developed.

WHICH ANESTHESIA ONE SHOULD CHOOSE?

One should aim for stable hemodynamics so as to maintain organ perfusion. Many a times, the procedures are done as day care. The type of anesthesia extends from monitored anesthesia care to general anesthesia with or without controlled ventilation. The anesthesia is planned depending on the type and duration of the procedure and age of the patient. It is always wise to select the general anesthesia with endotracheal intubation with controlled ventilation, for device placement, patients in whom transesophageal echocardiography monitoring is planned and in case of pediatric patients. Decision of type of anesthesia is always finalized after discussing with cardiologist and patient.[11] We anesthesiologists have the habit of connecting oxygen immediately to the patient once it he/she enters the operation theater. However, in CCL, we should discuss with the cardiologist whether blood oxygen saturation study will be done with room air or not. A good coordination between both will avoid such problems.

For sedation, different drugs with different routes are available. Drugs such as midazolam, diazepam, fentanyl, morphine, chloral hydrate, ketamine, and propofol are used depending on the age and pathology.

Regional anesthesia and central neuraxial blockade are also practiced, which carry the advantage of postprocedure analgesia and prevention of thromboembolic events. It should be kept in mind that most patients receive heparin during the procedure and anticoagulants in post procedure time. Anesthetic complications related to anticoagulants can be avoided if guidelines are followed.[12]

PEDIATRIC CARDIAC CATHETERIZATION LABORATORY PROCEDURES AND ANESTHESIA

Many a times, pediatric patients are posted for angiography to diagnose and understand the complex heart disease, which will assist in planning for cardiac surgery. Nowadays, the CCL study has become a gold standard technique.[13] In both diagnostic and therapeutic procedures, sedation or anesthesia is mandatory mostly for all the patients. Therapeutic procedures such as device closure are performed most commonly. The pediatric cardiologists are specially trained for these procedures.[14] There is no classic anesthetic technique and decision about anesthesia has to be made after discussing with cardiologist. Ketamine and midazolam are the most safely used for sedoanalgesia purpose.[1516] Monitoring of respiration, avoiding hypoxia, hypercarbia and acidosis, and air embolism are must. The main key for successful anesthetic management is to understand the pathology and plan anesthesia accordingly.

Coronary angiography and percutaneous intervention

These are the most commonly performed procedures in CCL.[17] Coronary and other peripheral angiography usually does not require general anesthesia and can be performed after injecting local anesthetic at puncture site. Some patients may require anxiolysis and can be managed with supplemental benzodiazepines.

Percutaneous therapeutic procedures for congenital anomalies

Most commonly, the device closure of septal defect and coil placement is done in pediatric patients. General anesthesia with endotracheal intubation is preferred for such procedure as the ideas are to benefit the child and is to give maximum comfort to cardiologist while performing such procedures. Hemodynamic monitoring should be done during and after the procedure as sudden changes in the physiology is noted after placement of device.

PLACEMENT OF PERMANENT PACEMAKER AND AUTOMATED IMPLANTABLE CARDIOVERTER AND DEFIBRILLATOR

Monitored anesthesia care is usually preferred in case of placement of permanent pacemaker. This device can be placed percutaneously under mild sedation along with local anesthesia infiltration (sedoanalgesia).[18] It is not uncommon to encounter local anesthetic toxicity if cardiologist injects unnoticed toxic doses of local anesthetics. Anesthesiologists should always keep a watch on the toxic dose and restrict the cardiologist if required. In case of automated implantable cardioverter and defibrillator placement, the device is tested for shock delivery after inducing arrhythmias which is done under deep sedation or with general anesthesia.

OTHER PROCEDURES

Electrophysiological studies, endovascular stent or coil placement, percutaneous balloon valvotomy, etc., are performed in the CCL. The anesthesiologist plays an important key role in such procedures.

COMMON COMPLICATIONS

Air embolism[19]

Arrhythmias: various types of bradyarrhythmia and tachyarrhythmia are noted

Thrombus formation on device or applicator and embolization

Embolization of the device

Stuck guide wire or devices (failure to deflate after inflation)

Pericardial hemorrhage and tamponade: This is caused by wire damage to a cardiac structure[20]

Hypotension, hypertension, bradycardia, and tachycardia: All should be treated accordingly.

Sudden cardiac arrest[21]

Tet spell or cyanotic spell[22]

Anaphylactic reactions to contrast dye.[23]

HYBRID CARDIAC CATHETERIZATION LABORATORIES: THE PROSPECTIVE!!

A potential and life-threatening complication in CCL may occur during procedure and may require emergency surgical intervention.[24] HCCL is an integration of CCL and operating theater and needs adequate space. The precious time spent for shifting the patient from CCL to operation theater is avoided, thereby decreasing the mortality and morbidity.

MOBILE CARDIAC CATHETERIZATION LABORATORIES (MCCL)

The MCCL is a cardiac catheterization laboratory which is on wheels and provides sterile and air conditioned environment for the procedures. The van can be taken to any part of the country, on regular roads and serves the people who cannot reach to the cities where facilities are provided. The recovery of patient is considered in hospital or nursing home where modest facilities are available.[25]

CONCLUSION

Anesthesiologists should be prepared for both elective and emergency CCL procedures. There is a need of training the postgraduates to handle the emergency situations in such critical areas and get accustomed to it before they start practicing independently. Adequate knowledge, training, and skills of anesthesiologists working in CCL are required. Good coordination between anesthesiologist, cardiologist, and cardiothoracic surgeon reduces the morbidity and mortality.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.