INTRODUCTION
The following vignette provides an excellent picture of typical operating room (OR, theatre) anesthesia in a resource-poor venue1:
John, an anaesthetic clinical officer, is administering a general anaesthetic [and] performs a rapid sequence induction with thiopental and suxamethonium and intubates using his own laryngoscope and a tracheal tube that has been used dozens of times before … John carries all his own equipment with him, along with a supply of drugs for the day—anything left in theatre will disappear by tomorrow. Normal saline is running in through an 18G cannula that the patient’s family were asked to buy from the local pharmacy.
John administers 50 mg of pethidine—this may be the last analgesic the patient receives until the unpredictable visit of the night matron to the ward in 9 h time—and turns up the OMV [Oxford Miniature Vaporizer] to deliver 2% halothane. The inspired concentration must be estimated clinically because the halothane “expired” 8 months ago and the clinical effect is unpredictable. The EMO [Epstein-Macintosh-Oxford] vaporiser and a bottle of ether are on stand-by behind the anaesthetic machine, as we are down to our last bottle of halothane.… The modern anaesthesia monitor, looking out of place in these surroundings, was purchased, along with eight others, by the European project. The screen has a psychedelic tinge to it and I suspect it is on its last legs. The capnograph trace is flat, as the last remaining moisture trap has been “borrowed” for use in ICU, where it will be circulated around the four beds. The ECG trace is true, but periodically interrupted as the long out-of-date electrodes require a small drop of thiopental to improve their conductivity. The oximetry probe is a paediatric one and roughly taped with grubby Elastoplast around the man’s little finger.
John ventilates the patient using the Oxford Inflating Bellows as part of a draw-over system, aiming to keep him deeply anaesthetised and apnoeic using a high concentration of halothane. There are no muscle relaxants apart from suxamethonium. Emergency drugs, atropine and adrenaline, are drawn up on a redundant Boyle’s machine, which acts as a trolley and equipment store. A lone size H oxygen cylinder is deep in dust in the corner and has been empty for several years.
John requests a nasogastric tube, so I head to the locked anaesthetic store room where 10 or so years of unsorted donations to the department have piled up. After 15 min, I find one at the bottom of a box of out-of-date NG feed. I can tell by the look on his face that John is torn between using this valued commodity for this patient or saving it for the next.
Anesthesia’s three principal functions are to keep the patient alive through surgery, to make surgery painless, and to provide the best possible surgical conditions.
The purpose of this chapter and, in fact, this entire book is illustrated by two questions that Drs. Boulton and Cole posed in their series “Anaesthesia in Difficult Situations”2:
What would I do if had to give an anesthetic and operate on a patient in an isolated hospital 100 miles from the nearest outpost of civilization?
What would I take on an expedition to the Arctic … or in the Himalayas … or on a ship … or to an area of devastation following an earthquake or nuclear holocaust?
This chapter and the next are for clinicians who may need to administer anesthesia in austere situations with limited supplies and equipment. These chapters highlight medications that can safely be used by non-anesthesiologists (e.g., ketamine), little-used anesthetics that are generally available in austere situations (e.g., intravenous [IV] ethanol [ETOH]), and anesthetics available in austere settings that are not familiar to younger anesthesiologists from industrialized nations (e.g., ether, halothane), as well as classic basic methods of delivering anesthesia (e.g., open-drop). Those trained in anesthesia obviously are more familiar with these medications and techniques than are other clinicians. The key to providing safe and effective anesthesia is to use equipment and techniques that employ the skills you already possess.
Although international standards for anesthesia administration exist, shortages of trained anesthesiologists, equipment, and medications limit the extent to which these standards can be implemented.
A worldwide shortage of trained anesthetists means that in developing countries, other practitioners, including physicians, dentists, nurse practitioners, physician assistants, and paramedics, may need to provide general anesthesia with limited additional training and with minimal supervision.
The basic rule of thumb is that “a practitioner faced with the necessity of giving an emergency anesthetic, perhaps for the first time since his student days, is well advised to stick to a technique which he has at least seen used at one time or another.” If an experienced anesthetist must supervise or manage multiple inexperienced practitioners giving anesthesia, which may be the case in many situations, “the technique employed would have to be as simple as possible so that it could be quickly taught.”2
Commonly, the clinician must be both the surgeon and the anesthetist. In these cases, the rule is to “use local and regional methods where you can. If you have to give a general anesthetic, secure the patient’s airway and make sure that there is [an IV] running before you start. With a clear airway and [an IV line], most of your problems will be over. Induce and intubate the patient yourself, and don’t operate until anesthesia is stable.”3 During the procedure, have an assistant monitor the patient by continually checking the blood pressure (BP) and the pulse using an esophageal or precordial stethoscope.3,4 (See Chapter 5 for how to improvise these devices.)
One competent clinician, however, can both sedate patients and perform closed reduction of major joint dislocations and forearm fractures (shoulder dislocation, elbow dislocation, hip dislocation, and forearm fracture) safely without assistance. Optimally, the patient will have continuous monitoring during the procedure and until his vital signs and mentation stabilize near presedation levels.5
The World Health Organization (WHO) lists what they consider to be the essential medications for anesthetic care, although cost and supply problems may limit the anesthetics and associated medications (Table 16-1) that are available for local, regional, and general anesthesia.
| Percentage of Anesthetists With Medications Available | |||
|---|---|---|---|
| Always (%) | Sometimes (%) | Never (%) | |
| Nitrous oxide | — | 3 | 92 |
| Naloxone | 9 | 16 | 60 |
| Neuromuscular blocking agent | 15 | 12 | 69 |
| Neostigmine | 16 | 6 | 69 |
| Magnesium | 19 | 38 | 39 |
| Blood for transfusion | 23 | 59 | 16 |
| Labetalol | 29 | 29 | 30 |
| Hydralazine | 30 | 34 | 30 |
| Halothane | 38 | 16 | 39 |
| Spinal local anesthetic | 39 | 28 | 30 |
| Narcotic (IV/IM) | 45 | 30 | 21 |
| Vasopressor | 45 | 21 | 28 |
| Succinylcholine | 54 | 23 | 19 |
| Oxytocin | 57 | 31 | 7 |
| Thiopental | 59 | 24 | 15 |
| Oxygen | 63 | 25 | 10 |
| Ether | 68 | 20 | 9 |
| Intravenous fluid | 68 | 27 | 2 |
| Local block anesthetic | 70 | 18 | 7 |
| Epinephrine | 74 | 18 | 3 |
| Diazepam | 81 | 17 | — |
| Ergometrine | 81 | 14 | 1 |
| Atropine | 84 | 6 | 6 |
| Ketamine | 92 | 3 | 4 |
GENERAL ANESTHESIA GUIDELINES
Administering general anesthesia provides three benefits: (a) hypnosis, putting the patient to sleep; (b) analgesia, relieving pain; and (c) relaxation, easing the muscles sufficiently to perform the procedure, primarily in abdominal and some orthopedic cases.6
An anesthetist’s primary goal is to anesthetize patients and have them recover without ill effects from the anesthesia. Whether this happens depends a great deal on the anesthetist’s abilities and how carefully he follows the rules for safely anesthetizing patients (Table 16-2).
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Four of the five essential elements for general anesthesia may need to be improvised or omitted in austere situations: premedication, monitoring, induction medications, and oxygenation. In addition, anesthetists may need to use alternative maintenance drugs (anesthetics) or delivery methods.
Premedication provides mild sedation for the patient and counteracts some side effects, primarily excess salivation and increased vagal tone.
A wide variety of narcotics, benzodiazepines, phenothiazines, and other medications may be used for premedication. Try to use sedating anticholinergics (e.g., those with antihistamine activity) if the normal medication cannot be used. Premedications are usually administered parenterally, but many may be given orally.
Promethazine 50 mg (1 mg/kg) tablets, which also have anticholinergic activity, can be used in adults for nausea and very mild sedation. Give promethazine about 2 hours before anesthesia. This medication is particularly good if ketamine is used as a general anesthetic. Diazepam tablets, 10 to 20 mg (0.15 to 0.25 mg/kg), can be used as a tranquilizer before either regional or general anesthesia. Oral diazepam has a more rapid and reliable onset than does intramuscular (IM) diazepam.9 Diphenhydramine (Benadryl) is cheap and almost always available. It can be given parenterally or orally, and is both sedating and anticholinergic.
Considered by many anesthesiologists to be the only essential preoperative medication, atropine 0.4 to 0.6 mg dries secretions and diminishes vagal tone on the heart. Atropine may be administered IM 30 to 40 minutes before induction or diluted and given IV immediately before anesthesia.7 Atropine can also be administered orally in tablet form (0.5 mg in an adult) at least 20 minutes before the general anesthetic is administered. There is no harm if the patient takes it with a small amount (~20 mL) of water.9
In austere situations, anesthesia with only the most basic monitoring (even more basic than what you’re thinking) is the norm. Often the only monitoring is checking the pulse: either constantly with an esophageal or precordial stethoscope or at least every 5 minutes while taking a BP. You can also monitor the pulse by laying a finger just anterior to the tragus of the ear to feel the superficial temporal artery pulsate. Also, monitor the patient’s skin color, capillary refill, and the color of any blood from the surgical site, because these require no apparatus. A wisp of cotton taped near the nostril is a useful indicator that the patient is still breathing.7
Esophageal stethoscopes are particularly important during thoracic procedures. Only one earpiece is needed, although a modified stethoscope can also be used. Precordial stethoscopes (that can also be placed over the back) are particularly important to use during procedures on babies. Likewise, only one earpiece is needed, but the bell should be securely taped to the patient before the procedure begins.
Both IV and inhalation agents are often used for induction. Ketamine needs no induction agent.
Benzodiazepines, although not often used for induction, can be used for this purpose. Diazepam, often the most readily available benzodiazepine, can be used as an IV induction agent, although it has a longer onset and longer duration (i.e., longer “hangover”) than most other agents.10 The newer benzodiazepines generally work faster and have shorter half-lives.
The most feared complication during induction is laryngospasm. The traditional method of breaking a laryngospasm is to use constant positive pressure with an anesthesia bag or a bag-valve-mask (BVM). This normally breaks the spasm. A more rapid alternative is to apply pressure to the “laryngospasm notch.” Place the long finger of each hand into the most superior part of the depression behind the pinna of each ear. The fingertip should press against the ascending mandibular ramus anteriorly, the mastoid process posteriorly, and the base of the skull superiorly. Press very firmly inward toward the base of the skull while lifting the mandible to perform a “jaw thrust.” This action generally converts laryngospasm to laryngeal stridor within one or two breaths and, in another few breaths, to unobstructed respiration. The technique is effective in infants, children, and adults. Alternatively, clinicians have had similar success by applying digital pressure anterior to the tragus.11 If this is unsuccessful, spray the cords with lidocaine, and be prepared to do a cricothyrotomy (rarely needed).
In austere situations, oxygen is frequently unavailable, and so is considered a luxury. If oxygen is scarce, use it only to preoxygenate patients who will undergo brief apneic procedures, to induce and intubate small children,12 and to supplement anesthesia at altitudes >9000 feet (2743 m). Also provide it for patients with laryngospasm, acute desaturation, significant anemia (Hgb <9 g/dL), or heart or lung disease, and to those in shock.10
Also consider using oxygen when (a) inducing anesthesia in a patient using ether and air; (b) giving anesthesia with >8% ether; (c) doing a Cesarean section (C-section), but only until the baby is delivered; (d) patients have any respiratory disease or considerable airway secretions; and (e) the preoperative BP has fallen by >30%.
Theoretically, all patients may go through four stages (plus substages, or planes) of anesthesia, no matter which agent is used (Table 16-3). Ether is the anesthetic that shows all the classic stages, so the pattern with ether is described more fully in the “Ether” section in Chapter 17.
| Stage | Plane | Respiration | Response to Surgical Stimulus | Eye Signs | Cardiac |
|---|---|---|---|---|---|
| I. Analgesia | Voluntary control | Voluntary control | Voluntary movement | Adequate output | |
| Consciousness Lost | |||||
| II. Excitement (Delirium) | 1. Early | Irregular Coughinga Spasm | Actively purposefula | Lash reflex goesa Variable movement Disconjugate gaze | Possibly arrhythmias |
| 2. Late | Phonation Breath holdinga | Weakly purposefula | |||
| III. Surgical anesthesia | 1. Light | Regulara | Absent | Lid reflex gonea | Adequate outputb |
| 2. Moderate | Adequate | Eyes fixeda | |||
| 3. Deep | Tracheal tugc | Pupil dilateda | Hypotensionb | ||
| IV. Medullary paralysis | Absenta | Pupil of anoxiaa | Good contractionb | ||
| Death | Cardiac arrest | ||||
When administering anesthesia with basic equipment and few medications, tracking anesthetic stages can be a useful safeguard against over-medication.
Anesthetics vary widely in their effects, so use staging with the particular drug’s effects in mind. Staging follows the oversimplified, but useful, pattern that anesthetics suppress the central nervous system from the top down as blood concentration increases. This progression (stages) can be observed in the patient’s body movements, respiratory rhythm, oculomotor reflexes, and muscle tone. The following paragraphs describe the classic anesthetic stages.
There is suppression of the highest cerebral centers, with the patient gradually losing the sensation of pain. Patients remain conscious and rational, and have decreased pain perception. Muscle tone, breathing, and pulse are normal. Use Stage 1 anesthesia for obstetric analgesia and as a supplement to local anesthesia for minor procedures.
This stage begins when patients lose consciousness and become excited, struggle, and (possibly) become difficult to control. Patients retain their gag reflex and can protect their airway, although they breathe irregularly and may hold their breath. Their pupils generally dilate. Their abdominal muscles contract during expiration. They lose their eyelash reflex and have roving eye movements and dilated but reactive pupils. They retain reflex responses to any painful or irritating stimuli, including noxious anesthetic vapors.
In this stage, patients no longer respond to painful stimuli. Muscular relaxation progressively increases, spontaneous respiration diminishes, and patients lose their protective gag reflex. Non-anesthesiologists need only recognize two planes: acceptable (“light”) and too deep.13
This is the optimal anesthetic level for most patients during surgery. Patients’ breathing becomes regular again, although they will inspire deeply every 2 to 3 minutes. The eyes no longer move and, as the anesthesia level deepens, the pupils gradually dilate. The patient no longer moves and muscular tone decreases. The abdomen and chest move synchronously. An artificial airway or endotracheal (ET) tube may be inserted in this plane—but not earlier.
In this anesthesia plane, patients’ intercostal muscles become progressively paralyzed, eventually having paradoxical movement (moving in with inspiration). Sudden inspirations pull on the mediastinum and trachea, drawing it downward (the “tracheal tug”). Patients’ pupils become progressively less reactive to light. Abdominal surgery is very difficult at this anesthesia level if the patient is not pharmacologically paralyzed.
During stage 4, the brainstem’s respiratory center becomes depressed, which causes patients to stop breathing and lose all muscle tone. Their pupils are fixed and dilated. The heart may (as with chloroform) or may not (as with ether) be dangerously depressed.7 If a patient stays in this stage too long, his or her heart stops and the patient dies.13
