Ординатура / Офтальмология / Английские материалы / The Art of Phacoemulsification_Mehta, Alpar_2001

Lighting

Lighting often does not get the importance it deserves. It is important that the theatre can be lighted up properly, but equally important can also be darkened adequately.

It should be lighted sufficiently with shadowless theatre lamps of adequate power (minimum 50,000 Lux lamps). Though most of the surgery is done under the operating microscope, there are times when good peripherally focused lights are an advantage as for squint or oculoplasty surgery. Additional, movable goose-neck direct or

fiberoptic side theatre lamps are a necessity with good illumination and are especially good for capsulorrhexis in hard opaque cataracts. In addition, in case the theatre is darkened, provision should be made for spot lighting of the instrument trolley, the phaco unit, life-support systems, anesthetic equipment, with a lighting device on a rheostat so that the intensity is adequate for the scrub and circulating nurse and the anesthetist to see the equipment clearly, but is not so bright as to blind the surgeon. Many surgeons need a spot of light focusing on the operating table in addition to the operating microscope lights.

General illumination of the theater is also an important requirement. Though the powerful focused lights may be shut off, gentle illumination is needed in a theatre to allow for movement. Tube lights, ideally should never be used in the theatre as they are very distracting especially when the flicker increases as the tube gets a little older. In addition the flicker fusion frequency of the operating staff tend to be affected by the tube light especially when they are tired after a long session, increasing surgeon and staff irritability

Darkening the theatre enhances the contrast under the operating microscope and is extremely useful when doing a capsulorrhexis especially in a hard cataract. When the main theatre is darkened, provision needs to be made to gently illuminate the floor so that personnel can still move around without tripping on objects.

It is important that spot lighting should be kept off places where high reflectance stainless steel appliances and instruments are placed. This is to prevent extraneous glare from reflection from these shiny surfaces. The colors of the clothing worn by the operating room personnel should be soft and muted avoiding harsh colors. Pastel shades of blue, green or yellow are quite acceptable, however; red and ocher should be avoided

Air-conditioning and Ventilation

The ventilation of the room should be adequate and the air-conditioning sufficient to compensate for the number of personnel who are going to be in the room. The air-conditioning vents should be so arranged that they do not allow the air to be blown over the operating surfaces and at the same time keep the theatre cool. The ideal operating temperature would vary from surgeon to surgeon, however, a good comfortable temperature level in India is 70o C. The ideal air-conditioning would be one-way, taking in air from outside, filtering it, cooling it, and then expelling it out again after circulating through the operation theatre. Most theatres in India and in most of the smaller hospitals and nursing homes would seem to have windowmounted

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air-conditioning. The size and number should be adequate to provide good cooling with the air intake for fresh air always remaining open. It is very important that every evening following surgery the filters of the air-conditioner should be washed and soaked in a dilute solution of Cetavalon for half an hour prior to being re installed in the air-conditioner. The position of the units should be such that they do not blow over the sterile field, or blow directly onto the operating staff.

Noise Level in the Theatre

An operating theatre should be an oasis of calm. It is therefore important that the operating room should be located in a quiet area of the hospital or facility, and away from distracting sounds. It is essential that the windows be double-glazed (twin sheets of glass with an air-space between them) to keep the noise level down to a minimal level. It should be imperative that the operating staff learn from the beginning that unnecessary talk be kept to a minimum level and communications as far as possible should be by hand signs. This would guarantee that the surgeon, and the staff enjoy adequate peace and quiet to be able to concentrate on doing a good job. Background soft music should always be played in the operating theatre as it defuses tensions. The music should neither have a harsh beat nor irregular cadences.

Electrical Power and Outlets

The power points in the operating theatre should use high-quality reputable switches of an adequate output so that they are not overloaded and at the same time, good contacts are obtained between the plugs and the sockets. Often, even in so-called, Five Star facilities, it is seen that from a single outlet, using multipoint extensions, a number of lines are drawn. The wires then are left carelessly on the floor. All power points should be far away from the surgical field and preferably from a central hanging pod so that one cannot accidentally trip over the wires. In case it is required to trail a wire on the floor, it must be well protected with a masking tape so it is not accidentally pulled out in the dark.

The power outlets should be rated at a sufficient level to comfortably run the medical equipment. Over loading of the points often leads to failure at a critical time during surgery. It is also imperative that fuses be provided for every media outlet in the theatre of the self-adjusting type which could be reset simply by pushing in a button rather than the older wire-looped fuses. Sensitive instruments like a phacoemulsification machine and life-support evaluation systems (cardiac monitor or oxygen saturation monitors should always be run through an on-line UPS (uninterrupted power supply). This permits the surgery to be completed even if the lights go off or the power supply fluctuates or even trips (Fig. 1.2).

Power Generators

In India, as with many developing countries, power outage is not uncommon. It is important when the theatre is planned that one should compensate for this problem.

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Though it would be nice to have automatic switch-over power systems where the load is taken temporarily on batteries and then automatically shifted to the generated supply, it is a very costly system which is rarely used. Instead small power generators are utilized, adequate to run the theatre lamps, general lighting and power the instruments, including the Phacoemulsifier and support systems. It is important that the wiring be so organized that all that needs to be done, at the time of a power failure, is to turn on the switch and start the generator. The load on the generator should never exceed 75 percent of its rated output to prevent overload and tripping. The generators, which are usually run off petrol, kerosene or diesel, all have a few common features. They are all noisy, smelly and temperamental. Hence they need to be placed in a room with good ventilation, and isolated so that the sound and smell does not reach in the hospital or theatre complex. They should be serviced regularly, and personnel trained to start and run the units.

Scrubbing Facilities

The scrubbing room should be separate and kept outside the theatre. There is a specific reason for this. When gloves are worn there is always glove powder scattered around which is then be circulated in the room leading to contamination. Not only does this choke up the filters of the air-conditioner, but leave a patina of dust all over the sterile surfaces of the room.

Personnel in the Theatre

The ideal theatre room composition should be a scrub nurse, who surgically assists the surgeon, and a circulating nurse, who remains unsterile. In my theatre, where I like to have a turnover of around 12 to 15 cases per day, preferably in a threehour period, I find it best to use two separate teams. The scrub nurse who surgically assists me in the surgery will, after the case is finished, wash the instruments, place them into the sterilizing box and then put it herself into the autoclave. The scrub nurse then washes up again, dons a fresh gown and gloves and commences preparing for the next case preparing the table and opening up the disposables which are handed to her by the circulating nurse. The unsterile circulating nurse will open the presterile disposables, remove the instruments from the sterilizer, and hand them across to the scrub nurse. The second scrub nurse, who has been assisting me with the second cases, finishes, moves out, and the totally prepared first scrub nurse is ready to commence the next case.

This technique has a big advantage that the scrub nurse knows all about the instruments, where they are placed and their functional status. In addition it makes for far faster and more efficient application.

Theatre Autoclave

The autoclave should be a rapid action unit with flash sterilizing ability. A number of sterilizing systems are now available. Statim is a common one in usage (I use

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the Statim Cassette Autoclave, which has an 8-minute cycle, just perfect) and has preset operative timing levels, has adequate safety fail-safe built-in, and even has a small printout which confirms that the autoclaving cycle was complete and effective. The cassette system makes it very simple to insert and remove the instruments. Another good system is the Totawer and the Korean system which work in essentially identical manner. It is important to have a proper place to store the autoclaved instruments and theatre linen. The corridors and wall nooks are not for this purpose. It has to be in a well-ventilated room, far away from any traffic so that sterility is not compromised.

The Operating Table

The operating table has, as its primary requirement rock-solid stability even under deflecting forces, like inadvertent pressure at the head end, or accidental tail end pressure or lateral pressure. The standard operating table with the rotating axis in the middle is not suitable for ophthalmic surgery as the slightest pressure at either the head end of the table or the tail end of the table causes the entire platform to rock. When an operating microscope is being used, zero movement is permissible with any level of safety and efficiency. A very steady table is mandatory.

Some of the operating tables are exceptional, like the Marquette system which is, however extremely costly. Alternately, more economical systems like the EyeTech table seem to work equally well and are sufficiently rigid for ophthalmic use.

The table should be motorized permitting free movement both up and down in fine increments so that it could be fine tuned with the surgeon and the microscope in position. There should be the ability to tilt the head end of the patient a little up or down to compensate for those with a larger anterior/posterior diameter of the head, or when little children are being operated. It should wide enough to accommodate the patient, but narrow at the head end so that it does not impede the surgeon especially when temporal; surgery is being undertaken. It is also important that there should be adequate place under the table for the surgeon’s feet, the foot pedal console of the phacoemulsification unit, as well as for the foot pedal console of the operating microscope.

Foot-mounted electrical controllers for an operating table should be avoided as the irrigating fluid, be it normal saline, Ringer lactate, or balanced salt solution (BSS) is bound to splash on the floor leading to a short circuit. The operating table should also have the ability to take a right sided arm rest where the arm can be positioned by the anesthesiologist for placing an IV cannula for any intravenous injection or sedation as may be needed the need for inserting a very uncomfortable arm support under the back of the patient (Fig.1.3).

The mattress of the operating table should be at least 3 inches thick. The primitive 1 inch hard, unyielding, uncomfortable theatre mattress should be dispensed off with. Unlike general and orthopedic surgery where the patient is deeply sedated or even unconscious, the average ophthalmic patient is wide awake. With the advent of topical anesthesia, with the patient having to lie, totally without moving for

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long minutes at an end, the minimum which could be expected is a comfortable rubber mattress. The discerning and concerned surgeon should try sleeping on his or her own operating table to see its comfort level.

Therehasalwaysbeendiscussionastowhetherwristsupportisrequired.Proponents of the wrist support system feel that it helps in stabilizing the wrist, and at the same time permits a little cavity or gully for collection of fluids rather than letting the fluid rundown the face. On the other hand, there are others who feel that it restricts the freedom of movement of the hand around the face and since usually the forehead is already being used to support the fingers the presence of a wrist rest is superfluous. It is basically a surgeon’s choice. I personally feel it interferes more with the surgery than helps, and though I have used it in many operating theatres, have never felt that it was really necessary. Personally I feel it restricts the free movement of the phaco handpiece. However, it is an individual choice.

The Surgical Chair

Phacoemulsification requires both hands and both feet to be utilized simultaneously. It stands to reason that the surgical chair is an important piece of surgical equipment. It gives the surgeon stability, supports his back, it gives a comfortable seating arrangement. It is important to remember that the feet have to be kept on the pedals for the full time of the surgery, and the surgical chair must be so designed that it prevents any pressure on his thighs. It is imperative that the chair be very comfortable, for the surgeon will need to sit on it for long hours every day if he is to complete his surgical list. Any discomfort, overtime, tends to get magnified, which affects, in the final score, the surgical competence.

In the intracapsular days, most surgeons operated without any magnifying aids except for low-powered spectacle magnifiers or head-worn loupes, and operated standing.

The advent of extracapsular cataract surgery changed the entire gambit. The necessity of visualizing the red glow meant the use of a coaxial operating microscope became mandatory. With the use of automated irrigation/aspiration units, both feet needed to be utilized. Thus the surgeon had no option except to sit and operate.

Ideally the operating chair should have a minimum of five and preferably seven smoothly moving, nylon castors, to give total stability, with a lock on at least two of them, to immobilize the chair. The arm rest should be of adjustable height and properly padded and designed with a slight hollow so that during surgery the resting elbows should not slip off (with, as one may well expect, dire consequences). They should support the elbow, but at the same time, should neither restrict, nor interfere with, the surgeon’s movement. The chair should also fit easily under the operating table, with adequate space for the surgeon’s thighs. The area below the head rest should not be in contact with the chair or its armrests, neither should the base touch against the operating table. The height of the chair could be either electrically or hydraulically adjusted so that the appropriate height for each individual patient and the surgeon can be utilized. Finally, the chair must be grounded.

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Operating Microscope

The microscope is perhaps the most important single piece of equipment in the theatre. Without an exceptional microscope, good phacoemulsification is difficult, if not impossible.

The basic requirements are as follows:

Excellent optics with clear vision at the edge of the optics There should be no blooming or distortion of the image and the lenses need to be color corrected. The latest microscopes (Zeiss) have apochromatic optics.

Adequate depth of focus The entire lens should be visible from the front to the back without refocusing. This is very important since when doing phaco the traverse of the tip from the front to the back of the lens is almost 4 to 5 mm and it is important that excellent focus be available at all times.

Perfect coaxial optics Are of prime importance if a good red glow is to be visualized. In modern extracapsular cataract extraction (ECCE) and, even more so, phacoemulsification, the surgeon literally operates against the background of the red glow. A good glow from one edge of the pupil to the other is thus a basic requirement.

Good X-Y device The advantage is that the position of the microscope can be adjusted during surgery utilizing the foot controls without having to manually push a heavy microscope around. A good X-Y device also compensates for the little head movement which is to be expected during surgery.

Automated zoom magnification It is not absolutely essential but is extremely useful as one can zoom in for a difficult situation ( doing rhexis in a hypermature cataract, or to see the edges of the capsule while doing posterior rhexis) and then zoom out with a reduced magnification for more effective surgery.

Easily movable without damaging the unit Should be mounted on movable castors so that it could be positioned easily and locked in place in the operating theatre.

Proper and stable optics delivery The arm connecting the microscope head to the supporting pillar should have adequate movement but at the same time should possess rock-solid stability. It should be possible to position the microscope head easily and then lock the arms.

Tilt optics Not mandatory but makes a great deal of difference in comfort. The horizontal to vertical tilt arrangement (range of 90 degrees) is in the opinion of the author a really useful device as it makes the difference between operating comfortably and struggling and operating. It is particularly useful when operating on patients who cannot lie flat and who have to be literally operated in a 45-degree position. One can position the microscope to be parallel to the plane of the head and then simply tilt the optics to operate comfortably.

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Fig. 1.1: Layout of operation theatre with phaco on right

Fig. 1.2: Showing set-up with video, VCR, cardiac monitor, oxygen saturation monitor and cautery on right side of surgery

Preoperative Microscope Positioning

It is imperative that the microscope be positioned accurately at the time of commencing surgery. Ideally the microscope should be on the right side of the patient, the same side at which the phacoemulsification unit is kept. The left side is reserved for

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Fig. 1.3: Taken from the foot end of the patient. Anesthetist on the surgeon’s right side and instrument table on the surgeon’s left side

Fig. 1.4: Showing the double tubing Surge Suppression System attached to the author’s Alcon Legacy

permitting the patient to be shifted from the gurney or trolley to the table and the subsequent removal after surgery. The ideal place for keeping the instrument trolley is at patient’s left. The surgical assistant stands on the same side. The operating microscope camera should have its monitor placed at the surgeons right, set slightly

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Fig. 1.5: The balancing balls designed by

Dr Tony Fernandez for softening eye

behind the surgeon so that the scrub nurse and the anesthetist can both follow the progress of the surgery, at the same time it will not distract the surgeon.

An X-Y attachment is a very useful adjunct as it allows the stabilization of the optical axis to the patient’s eye during surgery without unnecessary coarse movements of the optical head. The X-Y device should be placed at its zero position prior commencing the surgery.

Most microscopes have removable autoclavable plastic, metal or silicone caps for the microscope. Alternatively, cloth covers, which can be autoclaved, can be utilized.

It is important that all the arrangements and positioning of the microscope be done prior to commencing the surgery.

The luminosity of the microscope should be kept at the lowest level consistent with good vision. It is important to remember that the so-called ‘cold” fibreoptic light is not really cold but simply not too hot. A good heat shield must be fitted in the microscope especially if the microscope has a filament bulb. Keep the light intensity low until required.

Prior commencing, the surgeon should place the focus at one-third position, i.e. if the traverse can be visually divided into three parts, it should be fitted in the upper third. This allows the surgeon to have more than adequate range during surgery. The surgeon should commence with the microscope focused at the limbus where the initial incision will be made. Placing the setting at the upper one-third position of the head traverse, enables the available traverse ( up-down movement) of the microscope to be utilized effectively.

It is also important to adjust the microscope optics to the surgeon’s ametropia and his interpupillary distance if the microscope is used in a multi-user environment.

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To enable good coaxiality so as to obtain an excellent red glow the corneal plane must be exactly at right angles to the microscope tube. Be certain to position the eye perfectly prior commencing. Many microscopes come with a small round macular occluder which can be brought into position after the critical part of the surgery is over to diminish the quantum of light entering the macula. A simple alternate technique is to change the angle of the optics immediately after the cortical aspiration is over and to dim the light. Modern phaco surgery is now so fast that sometimes one wonders whether it is really required, however it is a good practice and should be followed.

Footwear Use in the Theatre

The use of footwear is very much dependent upon the surgeon. I personally prefer to use stocking feet rather than using slippers or shoes as I personally feels that it gives far better control. The use of thin-soled tennis shoes would perhaps work just as well. The thick-soled Nike and Adidas shoes though excellent in the sport field are not really useful as the fine control is lost.

Using the X-Y control with stocking feet is a snap as the toes can easily encircle the knob. However, thin-soled shoes do seem to work well. The problem comes about in utilizing the X-Y control on the microscope. Stockinged feet are able to comfortably go around the tip of the X-Y knob permitting exquisite control. The important guidelines to observe are comfort. Be careful not to use loose floppy footwear like rubber slippers or cotton slippers, as they tend to slide over the footswitch area and can, in a critical moment, jam the footswitch and precipitate problems.

The Patient in the Operating Theatre

Positioning the Patient in the Theatre

The patient’s head should be positioned in such a manner that the iris plane is parallel to the floor and perpendicular to the coaxial light of the microscope. In case the patient’s eyebrow is pronounced or the nose is pronounced, both of which would interfere with the surgery, one can easily shift to a full temporal approach. I personally prefer to enter at the 10 o’clock position in the right eye and the same in the left eye. The only time I change positions to a full temporal approach is when space is inadequate for a proper exposure.

It is always very tempting, after scrubbing, to enter the operating room and wear the gloves from the instrument trolley, next to the patient. It is important to don the rubber gloves prior to entering the theatre, and as far away from the instruments trolley as possible. Whenever gloves are snapped on, talcum/glove powder, which is on the gloves, tends to be liberated and then falls as a fine patina all over the instruments and the eye. Prior to commencing surgery the surgeon should wipe his or her hands with a sterile dry towel, after putting on the gloves so as to remove the excess gloves powder. Washing is also acceptable but must then be in copious distilled water as otherwise it simply cakes the gloves, making matters worse. The dry towel scrub is the best to remove excess glove powder.