Anaesthesia for Ambulatory Surgery
The practice of Day Surgery has been around for some times but it has been sporadic, often times unsafe and not properly understood. Increasing healthcare costs have contributed to the development of Day Surgery. Advancement in anesthetic induction agents and airway management has contributed to the their success. Advancements in endoscopic and other minimally invasive surgical procedures are contributing to the proliferation of better care for patient in these settings and offer a very bright future. Patient selection criteria are essential for their success and continue to be in future. This chapter explores the management of anesthesia in Ambulatory Surgery Centre (ASC), anesthetic pharmacology, pre operative selection criteria, postoperative discharge criteria and different modalities of anesthesia for Day Surgery patients.
Pre anaesthetic preparation:
There are some special considerations for anesthesia in Day Surgery. Selection of patients for Day Surgery essentially should fall between American Society of Anesthesiology (ASA) class I-II. In certain instances ASA class III patients can be entertained depending on the nature and brevity of procedure. Patients having uncontrolled hypertension, improperly managed diabetes, difficult airway and certain other systemic diseases make their management a little complicated. A complaint of random chest pain or on exertion must be properly investigated in middle-aged person and elderly. These patients require extensive monitoring and some times overnight observation and frequently untoward outcome. The cavalier attitude of "minor anesthesia for minor surgery" is prescription of trouble. Anesthesia department must therefore screen these patients carefully and refer them for proper preparation prior to putting them on operating room schedule. Proper pre operative evaluation avoids unnecessary cancellation, delays, and patient dissatisfaction and inconvenience to the patient’s family and waste of time of the surgery personnel.
Pre operative clearance must be done as soon as patient is scheduled for surgery. These patients should be called on to make sure that proper investigations are done. A guideline must be in place regarding the minimum level of investigations. Any patients presenting with a history of cardiac problem must have a baseline EKG. Patients presenting with any respiratory problem should have a chest X-Ray or result of Chest X-Ray available. If necessary pulmonary functions should be in place in order to decide the suitability of anesthesia. Patients having kidney diseases must have recent pertinent laboratory investigations. A recent consultation with the proper specialist should be on board, addressing the concerned problem and its implication to the impending procedures.
All patients must be asked about any adverse problems occurring during the surgeries in the past. Ambulatory personnel responsible for scheduling patients must give them clear instructions for the time they must report for surgery. Enough time must be given for a pre-anesthetic evaluation.
They must be instructed that provision be made for them to be picked up after the procedure and there must be some one to take care of them during the first 24 hours. Out of town patients must make proper arrangements to stay in town as per need basis.
Immediate Pre operative Review: A careful history should be reviewed to chart the allergies, systemic diseases requiring special consideration, medication and any adverse reaction to anesthesia. Uncontrolled hypertension, uncontrolled diabetes, abnormal cardiac rhythm, not compliant with NPO instructions are cause of great alarm and should be reasons for postponement of surgery until they are properly addressed. A careful airway assessment must be made to make sure that they do not present any intubation or airway problem. All patients should be asked for any adverse airway problem during past anesthetics. An algorithm should be followed for difficult intubation patients.
There are certain procedures that should not be done in ASC. Any procedure requiring blood or blood transfusion, procedures expected to require intensive postoperative monitoring. Uncontrollable pain, undue sedation is very important reasons for prolonged stay in ASC. Therefore care should be taken that proper analgesia is administered. Infiltration with a long acting local anesthetic such as Bupivicaine or one of its isomers at the incision site contributes to the comfort and reduction of pain medications.
Upset stomach leading to nausea and vomiting are the most important complaints after anesthesia and cause of prolonged stay for ambulatory patients. Smooth induction and proper timely administration of anti nausea medication are essential for their avoidance and good anesthetic management. This becomes even more essential, rather vital for patients presenting for Day Surgery. Special precaution should be taken to make sure a pertinent history is taken to see if some of the patients are more susceptible to nausea, vomiting, pain and apprehension for the procedure.
Guidelines that are set for inpatient anesthesia are applicable to all Day Surgery patients too. A clear policy must be implemented about "nothing by mouth" (NPO) several hours prior to surgery. Careful steps must be taken for those patients scheduled for surgery later in the afternoon that they are not starved for unduly long hours. This becomes even more important with diabetic and hypertensive patients needing their medication in the morning. Children can not be kept fasting for a long time and they should not be starved more than 4-6 hours, however their parents or guardian must be instructed against giving them anything solid. Nevertheless, nothing should be given within the NPO time guidelines if they cannot be scheduled early in the morning.
All patients having surgery in the morning should have nothing after midnight. Patients having surgery in the afternoon ideally should be fasting too but they could be allowed to have clear liquids (tea of coffee) prior to 7 AM and not more than a cup. Children have difficult time complying with NPO; their parents must understand the importance of fasting and must keep a watchful eye. Some mothers become very emotional seeing their small children fasting and may not realize the importance of fasting prior to surgery. Nothing by mouth literally must mean, "nothing by mouth". A 4-6 hours fasting must follow. Diabetic patients should skip their oral diabetic medicine or take half the morning insulin. A fasting blood sugar by means of finger stick should be done for diabetic patients when they present for surgery. A careful watch should be kept for these patients to avoid any untoward symptoms of hypoglycemia. Breast-feeding prior to surgery should also be restricted to 4 hours for children below one years of age.
Anti-sialagogue medications: (atropine, glycopyroate) are good in drying up the oral secretions. This helps prevent laryngospasm and undue salivation. They further help in preventing cholinergic responses like bradycardia. Administrations of these agents cause photophobia, dry mouth, and can make them uncomfortable. These side effects must be considered in pre operative area on individual basis. Some anesthesiologists therefore avoid their use and administer them on need basis.
Anti nauseating medications: e.g. metclopropamide (Reglan) 10 mg could be administered in pre operative area for gastric emptying. This can be further combined with Pepcid in patients having problem with Gastro Esophageal Reflux Disease (GERD). Patients with advanced GERD problem should be asked to take their medication on scheduled time with a sip of water and preferably should be asked for a longer fasting time and a light meal prior to the night of surgery. These medications also help in preventing postoperative nausea and vomiting. Other anti nausea medication like Ondesetron and other medication in this class that are effective are used just prior to emergence from anesthesia and do not have a considerable value given in prior to anesthesia. Other anti nauseating medications can be substituted because the cost of Ondesetron and one of its category medications is rather high. Dexamethasone 4-8mg is effective in patients having severe problem with nausea. This is also given prior to emergence from anesthesia.
Sedation: Apprehension about anesthesia and surgery varies with every individual. Short acting, sedative or anti anxiety medication like Midazolam 1-2 mg I V should be considered for such individuals. Longer acting sedatives are not the drug of choice as they linger in the system causing excessive drowsiness and prolonged stay. Children could be given oral Midazolam 0.5 mg/Kg up to a max of 10 mg in a syrup base half hour prior to induction. This is very effective for a very apprehensive child. Other anti anxiety medication can be given to the patients at home night before surgery if needed.
General Anesthesia:
Monitoring during anesthesia:
Different standards are perhaps followed around the world. In our
institution and for that matter in North America all patients must have
The monitoring equipments are expensive lack
of them require close observation. Unfortunately human errors can lead to severe
consequences. However pulse oximetery must be available where patients’
consciousness and airway is compromised. Pulse oximetery has been responsible
for saving many lives and for early warning of impending hypoxia. It should be
in every operating room and Post Anesthesia Care Unit (PACU or Recovery).
Anesthetic induction agents: Pentothal Sodium has been in use for several decades. After administration it is stored in the fat tissues for some time causing slow elimination and redistribution. This is often responsible for somnolence when combined with narcotic analgesics after discharge form PACU. The ideal anesthetic induction agents should be those that are metabolized rapidly and have no redistribution. Propofol (induction dose 3-5 mg/Kg) has replaced the Pentothal Sodium in this respect. Induction of anesthesia is rapid and short lasting. It has anti- nauseating property. It can be used as a sole anesthetic agent by intravenous infusion (75-150 mcg/Kg per minute). This can avoid use of Nitrous Oxide and other inhalational agents if anesthesiologist feels some patients present with a history of adverse experience with nausea and vomiting. Administration of Propofol can cause hypotension on rapid administration and especially if patient happens to be hypovolemic. It produces pain and burning on administration, which can be quite uncomfortable. Slow administration, combining with lidocaine, administration following lidocaine and some other technique some times help but problem remains. Administration in a bigger vein also help but that is not always possible since patients presenting for surgery are NPO and very apprehensive.
Analgesia: Short acting and intense analgesic is the drug of choice. A short acting analgesic like fentanyl could be combined to supplement anesthesia. Propofol and ultra short acting analgesic Remifentanyl is very effective in the surgery of head and neck where muscle relaxant is not recommended. Administration of Remifentanyl will require controlled ventilation, as it is a potent analgesic causing respiratory arrest. A combined infusion offers very effective anti-sympathetic response and rapid recovery. This is especially helpful where avoidance of postoperative gagging and coughing is important during emergence from anesthesia. Analgesic medications such as fentanyl, Demerol, morphine and other synthetic medications are good to supplement the analgesic component of the triad of anesthesia, analgesia and relaxation. The analgesic used during surgery decreases the sympatho-adrenaline response as well as supplement analgesia in immediate postoperative period. Non-steroidal anti-inflammatory (NSAID) agents like parenteral Ketorlac provide good postoperative analgesia by their anti-prostaglandin effect given at the end of the procedure. They are not effective for intra-operative analgesia.
Nitrous Oxide, Oxygen and inhalational agents remain for the most part mainstay for maintenance. Inhalational agents like Sevoflurane and isoflurane cause rapid induction and rapid elimination thus are the agents of choice. They do not require warming thus special complicated equipments as in case of desflurane. Some anesthesiologists feel that Nitrous Oxide causes nausea and therefore use a Propofol intra venous drip. In patients who have a strong tendency of upset stomach this is a reasonable alternative.
Airway Management:
Muscle Relaxants: Non-depolarising muscle relaxants are the choice medication for ambulatory patients. Rocuronium is a short acting agent. It causes very minimal or no histamine release. Careful administration can avoid the use of reversal agents. Other agents like atracurium etc. can also be used.
Depolarising agents e.g; succynyl choline or suxamethonium do not need reversal and thus cause less of muscarinic side effects. However they can lead to prolonged paralysis if a larger quantity is used and a person with hidden or known deficiency of psuedocholinesterase. Depolarising agents can cause incapacitating muscle aches especially since most patients are going to be resuming work and ambulatory the following day. For these reasons non-depolarising muscle relaxants are the choice medications for ambulatory patients.
Monitored Anesthesia Care (MAC): This has grown to be very important aspect of Day Surgery. A great many procedures such as Breast biopsy, Hernia repair, Hemorrhoid surgery, Cataract and many Gynecological and plastic surgery procedures are safely carried out under MAC with rapid discharge. In this technique after monitoring is in place Midazolam and a sub anesthetic dose of Propofol (1-2 mg per Kg) is administered. A short acting analgesic (fentanyl 50-100 mcg) is also used to induce analgesia. While patient is relatively deep, local anesthetic infiltration is done at the site of surgery or a nerve block e.g; pudendal, ilio- hypogastric and or ilio-inguinal is used. In Cataract surgery retro-bulbar or other respective block is used. There after the anesthetic is adjusted to keep a comfortable level where the patient is awake or in a twilight zone while procedure is carried out. Supplemental oxygen is administered by means of a nasal cannula or facemask. Patient’s vital signs pulse, blood pressure and Oxygen saturation is monitored in the similar fashion. Care should be taken that there is no compromise in patient’s respiration and circulation. If necessary, MAC can be switched to general anesthesia if the nature of procedure becomes more elaborate than initially planned. The conversion from MAC to General Anesthesia can also be undertaken if patient becomes apprehensive and fails to cooperate for the procedure. Since 10-20 percent of MACs are converted to General anesthesia all patients must meet the criteria as if they are going to have general anesthesia. They must have complete preoperative evaluation and follow the guidelines of NPO etc.
Neuro- Axial blocks: Epidural and spinal anesthesia have an equally important role in Day Surgery. Orthopedic procedure on the lower limbs, urological procedures and some of the gynecological procedures can be carried out with as little 50-60 mg of spinal lidocaine. For longer procedures a longer acting local anesthetic should be used. Epidural anesthesia is another option for certain procedures. An indwelling epidural catheter placement is for procedures scheduled to last several hours. It is not unusual now a day for a procedure to last for several hours in Day Surgery and still recover in a short time and go home at the end of the day. A smaller gauge needle 25 or 27 G. is ideal for spinal anesthesia. Smaller needles have least association with post spinal puncture headache. Despite best efforts younger female patients could suffer debilitating post spinal headache.
Nerve Blocks:
Nerve blocks are ideal for Day Surgery patients and they should be used more frequently. There is a perception that they take more time but if properly scheduled they take same amount of time.
Intra-venous Regional anesthesia is ideal for carpal tunnel release and other procedures of hand lasting less than 45 minutes. An I.V. cannula in the back of the hand is placed and securely taped. A rubber bandage (eshmark) is then wrapped around the forearm to drain the blood. A tourniquet is placed above the elbow inflated to the pressure above that of the systolic blood pressure. A double tourniquet is preferable. Lidocaine 40-50 ml of 0.5% is then injected. IV cannula is then withdrawn. Hand is prepped and surgery is accomplished.
Maintenance of a nerve block is equally important. Some people believe that maintenance of a nerve block is more challenging than performing the nerve block itself. This is because sometimes the block does not cover all the areas, it may take a little longer to set in, pressure from tourniquet becomes unbearable, patient has difficult time keeping still because of other conditions like arthritis or other aches and pains. These patients need careful sedation; often there is a very fine line between adequate sedation and complete loss of consciousness.
Post Anesthesia Care Unit (PACU):
PACU in ambulatory surgeries are split in to Phase I and II. Phase I is responsible for patients coming immediately after surgery. This requires monitoring of their vital signs, acute pain management, wound care, airway and other orders as ordered by the physician. In post operative area all patients recovering from general anesthesia must be administered supplementary oxygen to maintain normal oxygen saturation monitored by means of a pulse oximetery. Other vital signs must be charted at appropriate intervals. Once the patient is stabilized and awake enough to take care of himself and has been able to stand on his own and void, they are transferred to Phase II.
In Phase II patients are transferred to a place where they can sit with their family, allowed to have a light snack and a drink. Orthostatic hypotension is not uncommon initially because of the interaction of pain medication and anesthetics. Once the patient has been stable for a certain length of time about and hour or longer he is discharged in the care of his family and sent home.
Despite this, some times unpredictable outcome happens and provision must be made for certain instances for some patients to stay in the hospital. Patients who develop hypertension that is not satisfactory resolved. Unexpected cardiac rhythm disorders, respiratory problems, and unreasonable amount of discomfort etc. necessitate hospital admission and further care. Transferring of these patients is done by trained medical or paramedical personals. A qualified personnel and an ambulance is required where resuscitative equipments are available. It is a very risky proposition to transfer a patient on ventilator especially if it had to be far from the Center. This is therefore essential that selection criteria for Day Surgery are stringent. If transfer rate to the hospital is high then selection criteria should be revised so that they are very minimal.
23 hours observation:
Some times the nature of surgery is such that overnight
observation is pre planned. This is for patients where surgical drains are
placed or where more than usual amount of blood loss is expected in the
postoperative period, or the nature of surgery is going to be uncomfortable. A
hospital bed is a costly affair in United States. Some of the Centers and
hospitals have devised a provision where these patients have been allocated a
special overnight stay. It is known as "23 hours observation" as opposed to full
day or 24 hours. It is only for those patients who in all likelihood will be
discharged next day in the morning. A reduced amount of reimbursement is
provisioned for this kind of stay. Most patients in our facility needing this
kind of stay are those where an extensive procedure is planned e.g; extensive
ligament reconstruction of knee, cosmetic procedures etc. This is ideal for
young healthy patients needing extensive surgery. Patients requiring blood
transfusion, systemic problems, respiratory and cardiac monitoring do not fall
in this category, they need transfer to a hospital facility. If such patients
are planned to stay in the center, a medical doctor with nurses should be
available in the facility.
Mostly young doctors provide this type of service during their residency program trying to earn extra income moonlighting. These physicians should be certified for Advanced Cardiac Life support training and do not need to be from anesthesiology although they are preferable. Anesthesiologist must stay in the facility until such patient is present.
Home Going Instructions:
1. These patients must have some responsible
adult to take them home
The whole affair is very pleasant for the patients where they do not unnecessarily have to go through the long line of processing, through the big corridors, and big bureaucracy of getting a bed assignment. Fortunately with the Day Surgery the bed assignments which used to be a gut wrenching experience has caused lots of hospitals to reduce the bed sizes and become much more responsive to the needs of consumers.
FUTURE OF DAY SURGERY
Procedures in not too distant past that needed a week or more of hospital stay and 7-8 inches incision now have become a thing of the past. Anesthetic management, which required quite a long recovery from the medication, has given ways to quick recovery. Better instrumentation, better video equipment has contributed to the development of minimally invasive surgery. There is going to be continuous development in the surgical skills in time to come. Cost effectiveness, improving surgical prowess and convenience for the consumers hold a better future for the Day Surgery. While this is for certain there are going to be new challenges ahead.
In order to do more there is going to be pressure on anesthesia department and nursing personals to manage the whole experience efficiently, smooth and for shorter stay. There is going to be a need for better communication and cooperation between different departments e.g; scheduling, reception, transportation, billing, coding etc. Anesthesiologists will have to play a major role in this process. Scheduling and assignment of anesthesiologist of different skills for differing procedures becomes even more essential. In the past hospitals were built by the community leaders, philanthropist, industrialists and corporations. These people had a great vision. They administered the hospital for its fiscal soundness but had little understanding of the need of physicians and patients. Free standing Day Surgery will need more input from the anesthesiologist, surgeons and nurses. This is true to a large extent, but one who foots the bill will also call the shots.
For this reason it is imperative that physicians who run such centers take a collective fiscal interest keeping the interest of their patients foremost to reap the rewards of professional and financial fulfillment. Financial fulfillment is a bad word but that is essential in order to keep the interest of their patients foremost.
In our free standing Center of the Cleveland Clinic foundation on an average 40-50 procedures are done everyday. It has seven operating rooms and 3 rooms for endoscopic procedures not requiring anesthesia care. There is pressure to make provision for more rooms and do even more extensive procedures. Anesthesiology department coordinates with all different surgeons to accommodate their request for the time.
Block assignments are developed for certain days for certain surgeons and difficulty remains. Special caution must be used to make sure that a true practical time interval is allocated in between the cases so as not to cause inconvenience to the surgeon following after one another. I suspect this problem has been with us and will continue to be there. But then what we had thought not possible in our lifetime has become a daily routine affair.
A well-managed Day Surgery facility deserves a good anesthesia department but a poorly run facility will need one to make it run well.
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