BULLETIN OF THE NEW YORK ACADEMY OF MEDICINE
MARCH 1975
VOL. 5i, No. 3
REQUIREMENTS FOR ANESTHESIA: LOCAL ANESTHESIA* DAVID H. RHODES, M.D. Vice-Chairman, Division of Ophthalmology Mercy Hospital Clinical Assistant Professor of Ophthalmology University of Pittsburgh School of Medicine Pittsburgh, Pa.
I N medicine and surgery, when there are several ways of doing something it is usually an indication that none is fully satisfactory. However, in the case of anesthesia for ocular surgery, developments in anesthesiology have provided the ophthalmologist with the opportunity to choose between a number of satisfactory techniques. What is required of anesthesia in ocular surgery? i) Obviously any morbidity and mortality related to anesthesia must be kept at an irreducible minimum. 2) Adequate operative conditions must be provided. Ocular surgery can be divided into two classes: a) operations in which the globe is not opened and b) operations in which the globe is opened. In operations which do not involve an open globe there is much *Presented at a combined meeting on Anesthesiology in Ophthalmology held by the Section on Anesthesiology and Resuscitation of the New York Academy of Medicine and the New York Society for Clinical Ophthalmology at the Academy March 4, 1974.
368
368
H. RHODES D. H. D.
more leeway for aberrations in surgical conditions, with no more serious consequences than inconvenience or delay during the procedure and perhaps some uncomplimentary remarks by the surgeon. Intraocular surgery, however, demands perfection in the surgical conditions provided. Control of the tissues is tenuous at best. Once vitreous starts to flow it is not replaceable; the best we can do is to minimize late complications. Moreover, intraocular bleeding is essentially uncontrollable except by the grace of the Almighty. A coughing, straining, retching, or restless patient-either awake or asleep-can precipitate either or both of these complications and jeopardize the eye. Although recent improvements in the techniques of corneal suturing have significantly reduced postoperative hazards to the eye, we must continue to give attention to what happens to the patient after he leaves the operating table. When local anesthesia is used, the ophthalmologist must assume responsibility for this care; when general anesthesia is given, the anesthesiologist must assume a share of the responsibility until all the effects of anesthesia have been dissipated. With the option of either general or local anesthesia, what factors influence the ophthalmologist's choice? The extent of the operation is an important consideration. A large surgical field weighs the choice toward general anesthesia. Similarly, long duration of the operation is an indication for general anesthesia. The patient's age is a factor, inasmuch as general anesthesia is necessary in young children but may be contraindicated in advanced age. Between these extremes age is not an important determining factor. No elective operation should be performed unless the patient is in optimum physical and mental condition. In situations where the best condition attainable still leaves a significantly increased risk for general anesthesia, local anesthesia should be used unless this risk is outweighed by other considerations. The patient's mental and emotional status may, however, preclude the use of local anesthesia. Patients with whom communication is impeded by language or deafness also usually need to be operated on under general anesthesia. In the selection of anesthesia, the rapport between the ophthalmologist and the patient and between the ophthalmologist and the anesthesiologist are crucial. Satisfactory local anesthesia for intraocular surgery requires the surgeon to have good communication with the patient, and the patient must trust the surgeon. Bull. N. Y. Acad. Med.
REQUIREMENTS FOR ANESTHESIA: LOCAL ANESTHESIA
3 69
The anesthesiologist has all the tools needed to provide adequate operating conditions for intraocular surgery; in addition, he must understand what is expected of him. If communication between the surgeon and the anesthesiologist is not adequate to convey this understanding, general anesthesia poses an intolerable risk for an intraocular procedure. The ophthalmologist must assess his own personality as well as that of the patient. If he has a calm, deliberate manner, even in the presence of the inevitable occasional complication, he can choose either local or general anesthesia on the basis of the preceding factors. If he has nervous habits or is subject to nervous reactions which agitate patients under local anesthesia, he should use general anesthesia if this is at all feasible. Local anesthesia requires just as much attention to detail as ophthalmologists expect of the anesthesiologist who provides general anesthesia. Premedication should be adequate but not excessive. It is easy to supplement medication which is too light, but not much can be done to counteract overmedication. A properly prepared patient should be relaxed and perhaps may drowse during the procedure but he will awaken oriented. The overmedicated patient will sleep, but will wake disoriented and often somewhat panicky. All too often this occurs at a crucial time, such as during the delivery of the lens. It is important that the ophthalmologist use drugs with which he is familiar and the effects of which he can predict. A special hazard is the use of drugs which potentiate each other in a degree which varies from patient to patient. Insofar as possible, one should also minimize the use of drugs which have side effects that make the patient restless. For instance, if the mouth has been dried excessively by atropine, the patient might move his jaws and his head in an attempt to salivate. Osmolytic agents may produce discomfort from headache and from distention of the bladder. The psychological preparation of the patient for local anesthesia is perhaps even more important than the type of premedication. The essential ingredient is the confidence of the patient in the surgeon. The ophthalmologist's office at the time of the first encounter with the patient is the place to start building this confidence. The surgeon should avoid disturbing this trust by frightening the patient with unexpected maneuvers or discomfort. Attention to the physical comfort of the Vol. 51, No. 3, March 1975
3 70
D. H. RHODES H.
RHODES
patient on the operating table is essential in keeping him relaxed. Patients with arthritis, orthopnea, and other ailments may require special positioning and adjustment of the table. Ventilation and temperature control are important. Unnecessary extraneous noise and conversation should be avoided, as these may elicit an unexpected response from the patient. The preoperative medical evaluation for a patient undergoing operation under local anesthesia is every bit as important as for general anesthesia if we are to reduce operative and postoperative morbidity and mortality to a minimum. Patients under local anesthesia should be monitored during the procedure, either by the surgeon with a stethoscope on the chest or by a nurse or anesthesiologist in attendance. Satisfactory uncomplicated local anesthesia requires that we give accurately placed injections of the minimum volume necessary to achieve satisfactory anesthesia and akinesia for the contemplated procedure. Procaine, i or 2%, is satisfactory for procedures lasting less than 45 minutes. Lidocaine, i or 2%, or mepivacaine, i or 2 %, will give at least go minutes of satisfactory anesthesia. Epinephrine in a concentration of I:200,000 will produce maximum local vasoconstriction and will reduce the likelihood of systemic absorption of the anesthetic. Up to 20 ml. of this concentration may be given without systemic effect. The use of epinephrine in concentrations of i: ioo,ooo or i:50,000 does not increase vasoconstriction but it does reduce the volume which can be injected safely. The addition of hyaluronidase increases the absorption of the anesthetic into the local sheaths and consequently augments the onset and effectiveness of the anesthesia. Akinesia of the orbicularis muscle is easily achieved with the Atkinson modification of the Van-Lint injection. This, in essence, is the blocking of the motor nerves to the orbicularis on a line situated along and immediately lateral to the lateral orbital rim. About 5 ml. of anesthetic will usually achieve this. The O'Brien block of the facial nerve as it emerges in the area of the temporo-mandibular joint will block the orbicularis adequately in about 70% of patients. However, anatomical variations in about 30% of patients reduce its effectiveness. In some patients the concomitant facial paralysis will produce undesireable restlessness as the patient tries to manage the saliva that collects in his cheek. The retrobulbar injection should be placed in the muscle cone, Bull. N. Y. Acad. Med.
REQUIREMENTS FOR ANESTHESIA: LOCAL ANESTHESIA
3 7 I
centered about one half to two thirds of the distance back to the apex. To place it accurately the surgeon must judge the shape and depth of the individual orbit. A needle with a rounded but cutting bevel will penetrate the intermuscular septum easily, and as it is rotated i8o0 it can be advanced into the cone with less trauma. Firm, constant pressure to the orbit for about two minutes after the injection will promote absorption of the anesthetic, reduce the likelihood of retrobulbar hemorrhage, and significantly reduce the intraocular pressure. The pressure should be released for a few seconds every 20 or 30 seconds, but the globe should not be massaged constantly, as the lens may become subluxated, especially in old patients with fragile zonules. Retrobulbar hemorrhage associated with injection of the local anesthetic manifests itself by progressive proptosis and increasing intraocular tension, with or without apparent subconjunctival bleeding. If this occurs, the intraocular operation should be cancelled and the eye bandaged with a pressure patch. The operation can be rescheduled when the proptosis subsides. Fairly extensive surgical procedures on the eyelids and adnexa can be performed under local anesthesia by means of regional block. Regional block avoids the injection of large volumes of anesthetic and the distortion of the tissues by local infiltration. The sensory fibers of this area are carried in the supraorbital, supratrochlear, infratrochlear, infraorbital, zygomaticofacial, and lacrimal nerves-each of which is anatomically accessible for blockage with one or two milliliters of injected anesthetic. Since there is overlap in the areas supplied by these nerves, two or more of these branches may have to be blocked for surgical work on a given part of the adnexa. If proper preparation and attention to detail are observed, local anesthesia is very satisfactory for almost any ocular operation. The same proper preparation and attention to detail also make general anesthesia satisfactory for almost any ocular surgical procedure, as my fellow-panelists will confirm.
Vol. 51, No. 3, March 1975
MARCH 1975
VOL. 5i, No. 3
REQUIREMENTS FOR ANESTHESIA: LOCAL ANESTHESIA* DAVID H. RHODES, M.D. Vice-Chairman, Division of Ophthalmology Mercy Hospital Clinical Assistant Professor of Ophthalmology University of Pittsburgh School of Medicine Pittsburgh, Pa.
I N medicine and surgery, when there are several ways of doing something it is usually an indication that none is fully satisfactory. However, in the case of anesthesia for ocular surgery, developments in anesthesiology have provided the ophthalmologist with the opportunity to choose between a number of satisfactory techniques. What is required of anesthesia in ocular surgery? i) Obviously any morbidity and mortality related to anesthesia must be kept at an irreducible minimum. 2) Adequate operative conditions must be provided. Ocular surgery can be divided into two classes: a) operations in which the globe is not opened and b) operations in which the globe is opened. In operations which do not involve an open globe there is much *Presented at a combined meeting on Anesthesiology in Ophthalmology held by the Section on Anesthesiology and Resuscitation of the New York Academy of Medicine and the New York Society for Clinical Ophthalmology at the Academy March 4, 1974.
368
368
H. RHODES D. H. D.
more leeway for aberrations in surgical conditions, with no more serious consequences than inconvenience or delay during the procedure and perhaps some uncomplimentary remarks by the surgeon. Intraocular surgery, however, demands perfection in the surgical conditions provided. Control of the tissues is tenuous at best. Once vitreous starts to flow it is not replaceable; the best we can do is to minimize late complications. Moreover, intraocular bleeding is essentially uncontrollable except by the grace of the Almighty. A coughing, straining, retching, or restless patient-either awake or asleep-can precipitate either or both of these complications and jeopardize the eye. Although recent improvements in the techniques of corneal suturing have significantly reduced postoperative hazards to the eye, we must continue to give attention to what happens to the patient after he leaves the operating table. When local anesthesia is used, the ophthalmologist must assume responsibility for this care; when general anesthesia is given, the anesthesiologist must assume a share of the responsibility until all the effects of anesthesia have been dissipated. With the option of either general or local anesthesia, what factors influence the ophthalmologist's choice? The extent of the operation is an important consideration. A large surgical field weighs the choice toward general anesthesia. Similarly, long duration of the operation is an indication for general anesthesia. The patient's age is a factor, inasmuch as general anesthesia is necessary in young children but may be contraindicated in advanced age. Between these extremes age is not an important determining factor. No elective operation should be performed unless the patient is in optimum physical and mental condition. In situations where the best condition attainable still leaves a significantly increased risk for general anesthesia, local anesthesia should be used unless this risk is outweighed by other considerations. The patient's mental and emotional status may, however, preclude the use of local anesthesia. Patients with whom communication is impeded by language or deafness also usually need to be operated on under general anesthesia. In the selection of anesthesia, the rapport between the ophthalmologist and the patient and between the ophthalmologist and the anesthesiologist are crucial. Satisfactory local anesthesia for intraocular surgery requires the surgeon to have good communication with the patient, and the patient must trust the surgeon. Bull. N. Y. Acad. Med.
REQUIREMENTS FOR ANESTHESIA: LOCAL ANESTHESIA
3 69
The anesthesiologist has all the tools needed to provide adequate operating conditions for intraocular surgery; in addition, he must understand what is expected of him. If communication between the surgeon and the anesthesiologist is not adequate to convey this understanding, general anesthesia poses an intolerable risk for an intraocular procedure. The ophthalmologist must assess his own personality as well as that of the patient. If he has a calm, deliberate manner, even in the presence of the inevitable occasional complication, he can choose either local or general anesthesia on the basis of the preceding factors. If he has nervous habits or is subject to nervous reactions which agitate patients under local anesthesia, he should use general anesthesia if this is at all feasible. Local anesthesia requires just as much attention to detail as ophthalmologists expect of the anesthesiologist who provides general anesthesia. Premedication should be adequate but not excessive. It is easy to supplement medication which is too light, but not much can be done to counteract overmedication. A properly prepared patient should be relaxed and perhaps may drowse during the procedure but he will awaken oriented. The overmedicated patient will sleep, but will wake disoriented and often somewhat panicky. All too often this occurs at a crucial time, such as during the delivery of the lens. It is important that the ophthalmologist use drugs with which he is familiar and the effects of which he can predict. A special hazard is the use of drugs which potentiate each other in a degree which varies from patient to patient. Insofar as possible, one should also minimize the use of drugs which have side effects that make the patient restless. For instance, if the mouth has been dried excessively by atropine, the patient might move his jaws and his head in an attempt to salivate. Osmolytic agents may produce discomfort from headache and from distention of the bladder. The psychological preparation of the patient for local anesthesia is perhaps even more important than the type of premedication. The essential ingredient is the confidence of the patient in the surgeon. The ophthalmologist's office at the time of the first encounter with the patient is the place to start building this confidence. The surgeon should avoid disturbing this trust by frightening the patient with unexpected maneuvers or discomfort. Attention to the physical comfort of the Vol. 51, No. 3, March 1975
3 70
D. H. RHODES H.
RHODES
patient on the operating table is essential in keeping him relaxed. Patients with arthritis, orthopnea, and other ailments may require special positioning and adjustment of the table. Ventilation and temperature control are important. Unnecessary extraneous noise and conversation should be avoided, as these may elicit an unexpected response from the patient. The preoperative medical evaluation for a patient undergoing operation under local anesthesia is every bit as important as for general anesthesia if we are to reduce operative and postoperative morbidity and mortality to a minimum. Patients under local anesthesia should be monitored during the procedure, either by the surgeon with a stethoscope on the chest or by a nurse or anesthesiologist in attendance. Satisfactory uncomplicated local anesthesia requires that we give accurately placed injections of the minimum volume necessary to achieve satisfactory anesthesia and akinesia for the contemplated procedure. Procaine, i or 2%, is satisfactory for procedures lasting less than 45 minutes. Lidocaine, i or 2%, or mepivacaine, i or 2 %, will give at least go minutes of satisfactory anesthesia. Epinephrine in a concentration of I:200,000 will produce maximum local vasoconstriction and will reduce the likelihood of systemic absorption of the anesthetic. Up to 20 ml. of this concentration may be given without systemic effect. The use of epinephrine in concentrations of i: ioo,ooo or i:50,000 does not increase vasoconstriction but it does reduce the volume which can be injected safely. The addition of hyaluronidase increases the absorption of the anesthetic into the local sheaths and consequently augments the onset and effectiveness of the anesthesia. Akinesia of the orbicularis muscle is easily achieved with the Atkinson modification of the Van-Lint injection. This, in essence, is the blocking of the motor nerves to the orbicularis on a line situated along and immediately lateral to the lateral orbital rim. About 5 ml. of anesthetic will usually achieve this. The O'Brien block of the facial nerve as it emerges in the area of the temporo-mandibular joint will block the orbicularis adequately in about 70% of patients. However, anatomical variations in about 30% of patients reduce its effectiveness. In some patients the concomitant facial paralysis will produce undesireable restlessness as the patient tries to manage the saliva that collects in his cheek. The retrobulbar injection should be placed in the muscle cone, Bull. N. Y. Acad. Med.
REQUIREMENTS FOR ANESTHESIA: LOCAL ANESTHESIA
3 7 I
centered about one half to two thirds of the distance back to the apex. To place it accurately the surgeon must judge the shape and depth of the individual orbit. A needle with a rounded but cutting bevel will penetrate the intermuscular septum easily, and as it is rotated i8o0 it can be advanced into the cone with less trauma. Firm, constant pressure to the orbit for about two minutes after the injection will promote absorption of the anesthetic, reduce the likelihood of retrobulbar hemorrhage, and significantly reduce the intraocular pressure. The pressure should be released for a few seconds every 20 or 30 seconds, but the globe should not be massaged constantly, as the lens may become subluxated, especially in old patients with fragile zonules. Retrobulbar hemorrhage associated with injection of the local anesthetic manifests itself by progressive proptosis and increasing intraocular tension, with or without apparent subconjunctival bleeding. If this occurs, the intraocular operation should be cancelled and the eye bandaged with a pressure patch. The operation can be rescheduled when the proptosis subsides. Fairly extensive surgical procedures on the eyelids and adnexa can be performed under local anesthesia by means of regional block. Regional block avoids the injection of large volumes of anesthetic and the distortion of the tissues by local infiltration. The sensory fibers of this area are carried in the supraorbital, supratrochlear, infratrochlear, infraorbital, zygomaticofacial, and lacrimal nerves-each of which is anatomically accessible for blockage with one or two milliliters of injected anesthetic. Since there is overlap in the areas supplied by these nerves, two or more of these branches may have to be blocked for surgical work on a given part of the adnexa. If proper preparation and attention to detail are observed, local anesthesia is very satisfactory for almost any ocular operation. The same proper preparation and attention to detail also make general anesthesia satisfactory for almost any ocular surgical procedure, as my fellow-panelists will confirm.
Vol. 51, No. 3, March 1975
