A person who is unconscious, whether because of injury or illness or because of the influence of general anaesthetic drugs, lacks many vital and protective reflexes and depends on other people for protection and maintenance of vital functions. It is the duty of the health staff to ensure that the patient is protected during this critical period. One person must never act as both anaesthetist and surgeon at the same time; a trained person must always be available specifically to look after the airway, monitor the patient and care for all vital functions.

CARE OF UNCONSCIOUS PATIENTS

Position

Always induce anaesthesia with the patient on a table or trolley that can rapidly be tilted into a steep, head-down position to deal with any sudden onset of hypotension or, should the patient vomit, to allow the vomit to drain out of the mouth instead of into the lungs.

Once anaesthetized, the patient should not be put into an abnormal position that could cause damage to joints or muscles. If the lithotomy position is to be used, two assistants should lift both legs at the same time, and place them in the stirrups, to avoid damage to the sacro-iliac joint.

Eyes

The eyes should be fully closed during general anaesthesia or the cornea may become dry and ulcerated. If the lids do not close “naturally”, use a small piece of tape to hold them. They should always be taped in this way if the head is to be draped and additional protective padding is advisable. If the patient is to be placed in the prone position, take special care to prevent pressure on the eyes, which could permanently damage vision.

Teeth

Teeth are at risk from artificial airways and laryngoscopy, especially if they are loose, decayed or irregularly spaced. Damage from oral airways most often occurs during recovery from anaesthesia, when an increase in muscle tone causes the patient to bite. Laryngoscopy may damage teeth, particularly the upper front incisors, if they are used as a fulcrum on which to lever the laryngoscope. It is safer to remove a loose tooth deliberately because, if dislodged by accident, it may be inhaled and result in a lung abscess.

Peripheral nerves

Certain peripheral nerves, such as the ulnar nerve at the elbow, may be damaged by prolonged pressure. Others, such as the brachial plexus, may be damaged by traction. Careful attention to the patient’s position and the use of soft padding over bony prominences can avoid these problems. Tourniquets, if used, must be carefully applied with padding and must never be left inflated for more than 90 minutes as ischaemic nerve damage may occur.

Respiration

Unrestricted breathing is essential for the unconscious patient. Make sure that the surgeon or assistant is not leaning on the chest wall or upper abdomen. Steep, head-down positions restrict movement of the diaphragm, especially in obese patients, and controlled ventilation may therefore be necessary.

If a patient is placed in the prone position, insert pillows under the upper chest and pelvis to allow free movement of the abdominal wall during respiration.

Handle patients gently at all times, whether they are awake or unconscious.

Burns

Protect the anaesthetized patient from being burned accidentally. Beware of inflammable skin cleaning solutions that can be ignited by surgical diathermy. To prevent diathermy burns, apply the neutral diathermy electrode firmly and evenly to a large area of skin over the back, buttock or thigh. If other electrical apparatus is in use, beware of the risk of electrocuting or electrically burning the patient.

Hypothermia

Keep unconscious patients as warm as possible by covering them and keeping them out of draughts. Most general and regional anaesthetics cause skin
vasodilatation, which increases heat loss from the body. Although the skin feels warm, the patient’s core temperature may be falling rapidly. Hypothermia during anaesthesia has two harmful effects:

MONITORING

A monitor is, strictly speaking, a device that warns or alerts you to an abnormal event, such as low blood pressure, by sounding an alarm. A manual blood pressure cuff will not warn you of anything – it simply measures blood pressure – and you have to know something is wrong. The term “monitoring” has been extended to mean “actively looking for abnormal patient events”. In other words, the major part of this job lies with the person doing the measurement who must actively seek the information.

Monitoring means looking at the patient.

In the past 20 years, more technological progress has been made in the field of monitoring during resuscitation and anaesthesia than in most other fields of medicine. These developments have made it possible to conduct a case almost without laying a hand on the patient, yet remain informed of the pulse, blood pressure, respiration, oxygen saturation, skin temperature or other physiological change.

However, the prohibitive training and equipment costs involved (both in capital outlay and maintenance) to sustain this advanced technology mean that anaesthetists in the developing world will usually not have more than the basic traditional monitoring tools (blood pressure cuff and stethoscope) with perhaps the chance of a pulse oximeter if they are lucky. Thus, the sensory
system of the anaesthetist him/herself becomes the most important monitoring device. The only maintenance it requires is to use it.

It is a fundamental rule in anaesthesia that you must never leave your patient unattended.

The five senses are: hearing, smell, sight, touch and taste. Only the last one is of little use to the alert anaesthetist. The first four are essential. Unfortunately, the word ‘alert’ is often changed to the overused word ‘vigilant’ and after being declared very important, is then, in practice, disregarded.

The non-alert anaesthetist does not observe the things going around him or her and does not recognize a change in the patient’s condition. Such a person fails to act logically to react to changes, and is undoubtedly the greatest hazard for the patient under anaesthesia.

Sophisticated monitoring devices sometimes act as a distraction to an anaesthetist who would do a better job with a manual blood pressure cuff and a finger on the pulse.

It is usually more important to look at the patient than the equipment but the alert anaesthetist pays constant attention to both.

Imagine your own “zone of interaction”, that is a physical space around you. Events occurring in this zone may affect your work and are your concern. Expand this space outward so that it meets and interacts with the equivalent zones of other people in the operating room and you communicate with them.

Sometimes two or more anaesthetists organise themselves into a “group anaesthetist” to conduct anaesthesia, perhaps for a difficult case. This can be very dangerous for the patient because, firstly, no one person is in charge and, secondly, communications within the group may be poor. It is often necessary to have one or more assistants for a case, but remember that there must always be only one person in charge of anaesthesia. That person delegates a specific task to an assistant, such as “take the blood pressure” and the assistant then reports back the result to the anaesthetist in charge of the case. If, for example, the blood pressure is found to be low and halothane is on 3%, the person taking the blood pressure should inform the anaesthetist in charge who then decides what to do about it, rather like the captain of a ship who ultimately has responsibility for that ship.

If the person in charge goes off duty while the patient is still on the table, he or she must hand over to another person in charge.

Observe the general operating room surroundings.

Reduce unnecessary noise. Noises may distract you from hearing important things going wrong with your patient or that some equipment is malfunctioning. For example:

Excessive operating room background noise from music or too many people talking at once is a distraction. Ventilators and monitoring devices cannot be heard.

Operating room chatter means not thinking about the patient.

Smells may indicate:

Check whether the temperature of the room is too hot for the staff or too cold for the patient and assess whether a warming blanket is needed.

Observe the operating table. How does it work? Is it too high, too low, tilted, braked?

Check the location of important equipment and drugs.

If there are wires and tubes on or around the patient or the operating table, make sure that they are not tangled up, knotted, twisted, kinked or lying on the floor. Check that the sucker tube will reach the patient.

Most important of all, monitor the oxygen flow to the anaesthesia machine or patient circuit (perhaps by feeling the flow of gas against your face). Ensure you can generate a positive pressure with the bag or bellows to inflate the lungs.

Observe the patient immediately before anaesthesia.

In addition to making a preoperative assessment on the ward, just before anaesthesia, observe the awake patient on the table from the psychological
viewpoint. The patient’s expectations of treatment and reaction to being in this strange environment will affect the changes in blood pressure and other
autonomic functions during anaesthesia and the need for postoperative analgesia.

Monitoring spontaneous respiration

You should monitor respiration movements in spontaneously breathing patients under anaesthesia. During spontaneous breathing, observe the respiratory rate and tidal volume by looking first at chest and abdomen, then at your anaesthesia apparatus, that is the movement of the bag or bellows or the movement of, and noise from, the breathing valve, such as an Ambu valve. Smooth, regular, spontaneous breathing is itself a useful sign that all is well. If hypotension from unsuspected (or unreported) operative haemorrhage occurs, the reduced cerebral blood flow means there will also be a change in the breathing pattern or breathing may cease altogether.

General anaesthesia with spontaneous breathing, therefore, used widely in developing countries, has valuable inherent safety aspects.

However, as always, you must check. Every few minutes, squeeze the bag or depress the bellows and make sure there is a satisfactory corresponding movement of the chest or abdomen. A problem with a partially blocked or
kinked endotracheal tube, or one that has moved down and entered the right main bronchus will be detected this way.

Monitoring the depth and rate of breathing also informs you about the level of anaesthesia. Different anaesthetic agents will produce different characteristics in the breathing pattern:

If you cannot see the chest or abdomen, rearrange the drapes so that you can.

Whatever the method of maintaining anaesthesia, it is a general rule that more anaesthesia will reduce respiration (both in the rate and tidal volume) so, again, spontaneous breathing has the safety feature that even if the anaesthetist is not monitoring the movements of respiration at all, the patient breathing a volatile agent will regulate the depth of anaesthesia automatically and will not get an overdose.

Monitoring respiration with IPPV

IPPV means Intermittent Positive Pressure Ventilation. If you have a ventilator you also must have the monitoring apparatus to make it safe. The anaesthetized patient connected to a mechanical ventilator can far more easily receive an overdose than one breathing spontaneously. Pay constant attention to the blood pressure and heart rate.

The commonest way to give a fatal overdose of anaesthetic is by mechanical ventilation (IPPV).

Other essential respiratory monitoring of ventilated patients includes:

The normal upper limit for airway pressure (AWP) is 30 cm water. A low AWP (10–15) means compliant lungs and normal function. AWP above 30 may mean:

If the airway pressure is getting higher and higher as the operation proceeds, think of these things. Recognize that you will have problems with getting the patient to breathe spontaneously postoperatively. You may need to plan postoperative ventilation in the intensive care unit.

If you have an old ventilator with no alarms, you must be especially vigilant. You are the alarms.

No matter what ventilator you have, when connecting it to the patient for the first time, check that the inspiratory/expiration phases of the
ventilator correspond to the rise and fall of the chest and abdomen.

Monitoring the cardiovascular system
The cardiovascular system is a close second behind the respiratory system in order of monitoring, though equal in importance.

Feel the pulse rate, heart rhythm and pulse volume and compare them with the preoperative values. The best place to feel the pulse is at the wrist, palpating the radial artery. Other convenient sites are the temporal artery or brachial artery.

Pulse rate

The pulse or heart rate varies greatly with age, method of anaesthesia and pathology. Neonates and babies should have a heart rate between 100 and 150. Older patients do not tolerate tachycardia well and adults ideally should not have a heart rate much above 100. However, heart rate is increased by:

A mixed picture emerges which the alert anaesthetist must observe and interpret, adjusting the methods of patient management so that dangerous abnormalities or changes in the cardiovascular system are returned towards normal.

In general, a spontaneously breathing patient on a higher dose of volatile agent as the sole anaesthetic, with no opiate given, will have a heart rate higher (90–120) than one being ventilated, having been given a muscle relaxant and mixed volatile agent/opiate anaesthesia (70–90). The latter is called a balanced technique.

A low heart rate is less easy to interpret and may have many causes. It may be normal, for example in a sportsman, or due to excessive vagal tone such as in organophosphate poisoning. A heart rate persistently below 50 in an adult and below 90 in a neonate should be treated.

Never allow yourself to be denied access to monitoring of respiration, pulse and blood pressure.

Heart rhythm

The heart rhythm is more difficult to monitor. The presence of an arrhythmia can be detected by feeling an irregular pulse at the wrist. The actual diagnosis of the arrhythmia – and, therefore, the decision on correct management – usually requires an ECG monitor. Fortunately, because ischaemic heart disease is rare in developing countries, serious abnormalities of rhythm are uncommon. Many arrhythmias occur under anaesthesia, are not detected by anyone and
resolve spontaneously after recovery causing no harm.

If you detect some abnormality in feeling the pulse that is worrying or new, or you see it on the ECG screen, consider the following options.

Pulse volume

Pulse volume means the fullness of the pulse. A good volume pulse may slowly become weak and thready during an operation where blood loss is not being corrected by replacement, even if blood pressure itself is maintained.

Blood pressure

Blood pressure is the single most important thing to measure, after feeling the pulse. While non-invasive blood pressure machines (NIBP) are widely used, a manual aneroid or mercury sphygmomanometer gives just as good a result. If you have an NIBP machine, find out how it works and remember to look at it. Set the reading interval to 3–5 minutes.

For manual checks, it is customary to use only the fingers (not the stethoscope) to get a value for blood pressure during anaesthesia because:

If the blood pressure goes down, consider:

If the blood pressure goes up, consider:

Using the stethoscope

Using the stethoscope on the chest to monitor breath sounds and heart sounds should not replace your senses as an input device: it should only add information. It must not be allowed to cause your “zone of interaction” to shrink. For example, many anaesthetists will tape the stethoscope to the chest, put both earpieces in place and devote their entire monitoring attention, very vigilantly, to the sounds of the heart and respiration. They then fail to notice other important complications of the procedure, such as falling blood pressure, haemorrhage, patient waking up, surgical crisis, hypoxia, hypothermia, drip running out or alarming monitors.

While everyone has a different way of using the stethoscope as a monitoring tool in anaesthesia, it is suggested that it should stay round your neck for occasional use all over the chest, rather than be fixed on the chest and fixed in your ears.

The weighted stethoscope plus earpiece is a better continuous monitoring tool than the ordinary stethoscope. This device has a heavy metal cylinder that sits on the chest and is connected via a long, lightweight tube to a comfortable single foam earpiece. It allows more freedom of movement, although the sounds are very faint compared to those from the usual stethoscope. Thermoplastic shaped earpieces can be individually made.

Monitoring after a spinal anaesthetic

Since the patient who has received spinal anaesthesia is awake, there is often an erroneous assumption that no monitoring is necessary. In fact, spinal anaesthesia may be associated with just as many complications as general anaesthesia, as the figures below show. Monitoring of blood pressure and respiration is, if anything, more important after spinal than after general anaesthesia. Check that cardiopulmonary resuscitation equipment is available and working and monitor cerebral perfusion by regularly talking to the patient and observing facial expression.

In many district hospitals, there is a high rate of complications of spinal anaesthesia, including severe hypotension (10%) and respiratory arrest (3%) These can easily occur when spinal anaesthesia is treated as an action to be performed rather than a process to be monitored. The result of such neglect can be a dead patient.

Monitor your patient very closely immediately after giving a spinal anaesthetic. One of the best ways to monitor such a patient is to talk to them throughout anaesthesia.

Depth of anaesthesia

Only in the worst-risk cases, where the condition of the patient is so poor that even light anaesthesia is life threatening, should you accept a very light plane of anaesthesia that unavoidably carries the risk of awareness. In most emergencies, you have sufficient control of the cardiovascular system to enable an adequate, non-aware state of anaesthesia to be maintained. The complication of awareness is generally confined to the paralysed patient who cannot show that anaesthesia is too light by moving.

When you give an intravenous hypnotic drug, ask yourself: are you sure you gave it? Where did it go? When turning on a vaporizer, check it is full.

Depth of anaesthesia can be monitored by looking at:

In all the above, you must also consider carbon dioxide retention due to hypoventilation. Check the ventilation urgently.

If a patient seems to be too ‘light’, check the ventilation first: the signs may be due to hypercarbia.

Urine output

A catheterized patient should have a bag connected so that you can check the urine output during the operation. If there is no urine, check the bladder to make sure there is no obstruction. Aim for a minimum output of 0.5 ml/kg per hour.

Electronic monitoring

Modern monitors often have multiple functions of oximetry, ECG, carbon dioxide, NIBP and temperature all together in one monitor.

Pulse oximeter

The pulse oximeter is simple to use. It informs about heart rate and especially oxygenation. Its greatest value is in diagnosing hypoxia during induction of anaesthesia in healthy patients.

Unfortunately, in emergency cases with circulatory collapse, when oxygenation information is most needed, the oximeter often cannot read the capillary pulse. In such cases, when the oximeter suddenly fails to read, it is a sign that deterioration is taking place. On the other hand, when the reading returns, it means the blood pressure has come up and your resuscitation efforts are perhaps being successful.

If the pulse oximeter will not give a reading, it usually means that something is wrong with the circulation.

Never believe the oximeter if the indicated pulse rate does not agree with the real one felt at the wrist. Readings from a pulse oximeter are often unreliable in infants and neonates with poor circulation. If an adult probe is used, there may be a 10% saturation difference between readings on the toe and the finger in babies.

Every case under anaesthesia should have the pulse oximeter in place, especially:

Remember, however, that when things go wrong, except in hypoxia, the pulse oximeter is almost useless.

Other monitors

Electrocardiograph (ECG)

Capnograph

Monitoring events

Make regular checks of the volume in the sucker. During caesarean section, it is important to differentiate between aspirated liquor and blood. The amount of losses must be added to the blood in the swabs and compared to the patient’s estimated circulating volume in order to give appropriate replacement fluids or blood.

Change of plan or operation

In places where diagnostic facilities are limited, there is more uncertainty about what will be found during surgery. The operation may turn out to be longer or shorter than expected – more usually the former. Pay attention to what is going on and adapt your anaesthesia to the changed circumstances.

Patient positioning

If head up or down tilt is needed this will affect cerebral perfusion (head up) or respiration (head down).

Watch the surgeon

Be prepared for the following: