CONTENTS
- Aviation Science
- Aviation Pharmacology
Aviation Science
Gas Law Variables:
- Molecule Number
- Temperature
- Volume
- Pressure
Important gas laws in aerospace medicine:
- Boyle’s law of Pressure-Volume
- Dalton’s Law of partial pressure
- Henry’s Law of in-liquid dissolved gas
- Charle’s Law volume-temperature
- Graham’s Law of gas diffusion
Boyle’s law of Pressure-Volume
The volume (V) of a given gas is inversely proportional to the pressure (P) to which it is subjected if the temperature remains constant.
Practical application of Boyle’s role in aerospace medicine
- With Increasing altitude, the gas volume also increases due to the reduction surrounding pressure.
- This is important because this means that gas volume in a closed space will also increase with increasing altitude.
- A pressurised aircraft can minimise the effects of Boyle’s law.
- Air in the in ET tube may also expand and this is minimised by placing water in the ET tube.
The follow are body cavities affected by Boyle’s law
- Sinuses
- Middle ear
- Inner ear
- Teeth
- Alveoli
- Bowels
Clinical Considerations
- Barotitis, barosinusitis, and barodontalgia (toothache)
- Reverse squeeze
- Conversion of simple pneumothorax to tension pneumothorax
- Hollow viscus rupture
- Pneumocephalus may worsen
- Gastric distention may occur during ascent making ventilation difficult in intubated patients.
- Colostomy bags.
Clinical importance of Boyle’s law in diving medicine
The absolute pressure will change at various depths below sea saw and this ultimately means that the gas volumes of gases used by divers will change at various depths below sea level.
Dalton’s Law of partial pressure
The total barometric pressure of a gas mixture at any altitude is equal to the sum of the partial pressure of the gases in that mixture.
Ptotal = P1 + P2 + P3 + … + Pn
Henry’s Law of solubility / Henry’s Law of dissolved gas in liquid
Definition
- The concentration of a gas in solution is directly related to the partial pressure of the gas above the solution.
- The weight of a gas dissolved in a liquid is directly proportional to the weight of the gas above the liquid.
- The mass of gas absorbed by a liquid is directly proportional to the partial pressure of the gas above the liquid.
- The mass of gas absorbed by a liquid is directly proportional to the partial pressure of the gas above the liquid.
Practical applications of Henry’s law.
A sudden decompression at high altitudes can result in decompression sickness.
Charle’s Law gas volume and temperature
Definition
- At constant pressure, the volume of a gas is directly proportional to the absolute temperature (K).
Practical applications in aerospace medicine
Warming the temperature of inspired gases increase in the volume of inspired gases.
Graham’s Law of gas diffusion
The rate of diffusion of a gas is inversely proportional to the square root of the mass of its particles.
| GAS | Molecular Mass (g) | Density (g/L) |
|---|---|---|
| N2 | 28 | 1.1 |
| O2 | 32 | 1.3 |
| CO2 | 44.01 | 1.98 |
| Ser No | GAS LAW | FORMULAS | CLINICAL ASPECTS |
|---|---|---|---|
| 1 | Boyle’s law (Pressure-Volume) |  | – Barotitis – Barosinusitis – Barodontalgia – Gastric distention at altitude |
| 2 | Dalton’s Law (Partial pressure) |  | – Hypoxia at altitudes. |
| 3 | Henry’s Law (solubility / dissolved gas in liquid) |  | – Decompression sickness |
| 4 | Charle’s Law (Gas volume and temperature) |  | – Warming the temperature of inspired gases increase in the volume of inspired gases. |
| 5 | Graham’s Law (Gas diffusion rate) (Gas effusion rate) |  | – CO2 and O2 diffuse at different rates |
_____________________________________________________________
ENT
Teed scale for MEBT
| Grade | Otoscopic Findings |
|---|---|
| 0 | Symptoms without TM signs. Normal Tympanic membrane. |
| 1 | Injection of the tympanic membrane, especially along the handle of the malleus. |
| 2 | Injection plus slight haemorrhage within the substance of the tympanic membrane. |
| 3 | Gross haemorrhage within the substance of the tympanic membrane. |
| 4 | Free blood in the middle ear as evidenced by blueness and bulging. Free blood in the middle ear – a fluid level. The bleeding is usually a dark red colour. |
| 5 | Tympanum is perforated. There is usually some evidence of petechial bleeding in the remaining eardrum. |
_____________________________________________________________
Aviation Pharmacology
| Drug | Permissibility in Aviation | indications | REF |
|---|---|---|---|
| ANTIDIABETIC DRUGS (Amayeza eswekile) | |||
| Metformin hydrochloride (Glucophage / Bigsens / Gloconorm / Diaphage / Diamin / Metphage / Metforal)  | Acceptable | DM II | SAMF 14th Ed pg 81 |
| Glibenclamide (Glycomin)  | Not acceptable | DM II | SAMF 14th Ed pg 83 |
| Gliclazide (Diamicron / Diaran / Diaglucide / Glytab / Glygard)  | Not acceptable | – DM II | SAMF 14th Ed pg 83 |
| Glimepiride (Amaryl / Glamaryl / Sulphonur)  | Not acceptable | – DM II | SAMF 14th Ed pg 84 |
| Insulin | Not acceptable | DM | SAMF 14th Ed pg 84 |
| Repaglinide (Novonorm) | Not acceptable | – DM II | SAMF 14th Ed pg 84 |
| Pioglitazone | Not acceptable | – DM II | SAMF 14th Ed pg 85 |
| CARDIOVASCULAR (Intliziyo nemithambo) | |||
| Hydrochlorothiazide (Ridaq / Hexazide)  | Acceptable | Hypertension | SAMF 14th Ed pg 157 |
| Indapamide (Dapamax / Catexan)  | Acceptable | – Hypertension | SAMF 14th Ed pg 158 |
| Amlodipine (Norvasc / Amladin / Amtas / Amloc / Amlodac / Amlate / Aprate / Norcard / Klodip)  | Acceptable | – Hypertension – Angina pectoris | SAMF 14th Ed pg 151 |
| Felodipine (Plendil)  | Acceptable | – Hypertension | SAMF 14th Ed pg 168 |
Nifedipine | Acceptable Short acting nifedipine is Not acceptable | – Hypertension – Angina pectoris – Raynaud’s phenomenon | SAMF 14th Ed pg 168 |
| Diltiazem (Zildem)  | Not acceptable | – Angina pectoris – Atrial fibrillation – Hypertension | SAMF 14th Ed pg 170 |
Verapamil hydrochloride  | Not acceptable | – Angina pectoris – SVT – Atrial fibrillation – Hypertension | SAMF 14th Ed pg 169 |
| Carvedilol (Carloc / Carvetrend / Dilatrend / Rubitrend / Vediblok) | Acceptable | – Hypertension – CCF | SAMF 14th Ed pg 165 |
| Labetalol (Trandate) | Not acceptable | – Hypertensive crisis – Controlled hypotension during anaesthesia | SAMF 14th Ed pg 166 |
| Metoprolol tartrate (Lopresor)  | Acceptable | – Angina pectoris – SVT – Hypertension – Hyperthyroidism – Myocardial infarction | SAMF 14th Ed pg 165 |
| Propranolol (Inderal / Indoblok / Pur-Bloka) | Not acceptable | – Hypertension – Essential tremor – Angina pectoris – Anxiety – Migraine prophylaxis – Thyrotoxicosis | SAMF 14th Ed pg 162 |
| Spironolactone (Aldactone / Spiractin) | Not acceptable | SAMF 14th Ed pg 151 | |
| Furosemide (Lasix / Furobe ) | Not acceptable | – Cardiac Edema – oliguria due to renal disease – Hypertension with renal failure | SAMF 14th Ed pg 159 |
| ANTITHROMBOTIC AGENTS | |||
| Aspirin (Ecotrin) | Acceptable Low Dose | SAMF 14th Ed pg 111 | |
| Clopidogrel (Acticlop/ Clopiwin/ Closolve / Plagrol / Plavix / Zyklot)  | Acceptable | SAMF 14th Ed pg 112 | |
| Enoxaparin sodium (Clexane) | Not acceptable | ||
| Heparin sodium | Not acceptable | SAMF 14th Ed pg 107 | |
Warfarin | Not acceptable | SAMF 14th Ed pg 107 | |
| ANTIHAEMORRHAGICS (Amayeza okupheilsa ukopha) | Not acceptable | ||
| Tranexamic acid (Tranic / Cyklokapron)  | Not acceptable | – Menorrhagia – Hyphaema – Dental extractions in Haemophilia | SAMF 14th Ed pg 119 |
| ORAL AND THROAT (Umqala) | |||
| Amphotericin B (Fungizone) | Acceptable | Systemic mycoses: – Cryptococcus – Mucormyocosis – Histoplasmosis – Emergomycosis – Blastomycosis – Extracutaneous sporotrichosis | SAMF 14th Ed pg 326 |
| Cetylpyridinium chloride (Cepacol) | Acceptable | – Superficial throat infection. | SAMF 14th Ed pg34 |
| Cetylpyridinium benzocaine (Cepacaine) | Acceptable | – Superficial throat infection. | SAMF 14th Ed pg 34 |
| Chlorhexidine gluconate | Acceptable | – Superficial throat infection. – Superficial gingival infections. | SAMF 14th Ed pg 34 |
| Miconazole (Dactarin) | Acceptable | Oropharyngeal fungal infection due to Candida Albicans | SAMF 14th Ed pg 36 |
| Nystatin (Candastan / Canstat / Nystacid) | Acceptable | Systemic mycoses: – Cryptococcus – Mucormyocosis – Histoplasmosis – Emergomycosis – Blastomycosis – Extracutaneous sporotrichosis | SAMF 14th Ed pg 36 |
| Pheno | Acceptable | ||
| Povidone-iodine (Betadine) | Acceptable | – Throat inflammation due to Candida Albicans and bacterial infections | SAMF 14th Ed pg 35 |
| Thymol (Listerine) | Acceptable | – Deodorant in mouthwashes. | SAMF 14th Ed pg 35 |
| Acid-related disorders | |||
| Aluminium hydroxide | Acceptable | – Dyspepsia – Reflux esophagitis | SAMF 14th Ed pg 39 |
| Calcium carbonate | Acceptable | – Dyspepsia – Reflux esophagitis | SAMF 14th Ed pg 40 |
| Magnesium Hydroxide (Milk of magnesium) | Not acceptable | – Dyspepsia – Reflux esophagitis | SAMF 14th Ed pg 40 |
| Esomeprazole (Nexium / Mitogut / Nexiam / Nexipraz Nesopram / Trustan / Nexomep) | Acceptable | – Duodenal ulcers – Gastric ulcers – GORD – Eradication of Helicobacter pylori | SAMF 14th Ed pg 42 |
| Lansoprazole (Lancap / Lansoloc) | Acceptable | – Heartburn (Short-term) – hyperacidity | SAMF 14th Ed pg 42 |
| Omeprazole (Corpocid/Lokit / Omez / Altosec / Probitor / Losec) | Acceptable | – Heartburn (Short-term) – hyperacidity | SAMF 14th Ed pg 42 |
| Pantoprazole (Pantoloc / Peploc / Pantocid / Conoran / Topzole / Pentoz / Topraflux) | Acceptable | – Heartburn (Short-term) – hyperacidity | SAMF 14th Ed pg 44 |
| Rabeprazole Sodium (Pariet / Rabemed) | Acceptable | – Duodenal ulcers – Gastric ulcers – Eradication of Helicobacter pylori | SAMF 14th Ed pg 44 |
| Cimetidine (Hexamet / Lenamet) | Acceptable 8 hours before flying | – Peptic ulcers – Reflux esophagitis – Zollinger Ellison syndrome – Prevent stress ulcers in critically ill patients | SAMF 14th Ed pg 45 |
| Nizatidine | Acceptable 12 Hours before flying. | – Peptic ulcers – Reflux esophagitis – Zollinger Ellison syndrome – Prevent stress ulcers in critically ill patients | SAMF 14th Ed pg 46 |
| Ranitidine (Zantac / Ultak / R-Loc) | Acceptable 12 Hours before flying. | – Peptic ulcers – Reflux esophagitis – Zollinger Ellison syndrome – Prevent stress ulcers in critically ill patients | SAMF 14th Ed pg 45 |
| Misoprostol (Cytotec) | Not acceptable | – Gastric ulcer – NSAID – Duodenal ulcer – NSAID | SAMF 14th Ed pg 46 |
| Sucralfate | Acceptable | – Gastric ulcer – Duodenal ulcer – Reflux esophagitis – Chronic gastritis | SAMF 14th Ed pg 47 |
| Antiobesity drugs (Amayeza alwa nokutyeba) | |||
| Cathine (Eetless / Relislim / Nobese No.1) | Not acceptable | – Obesity | SAMF 14th Ed pg 75 |
| Orlistat (Xenical) | Not acceptable | – Obesity | SAMF 14th Ed pg 76 |
| Sibutramine | Not acceptable |