Table 2. Selected case details of 52 patients with acute single chemical intoxication by seven aliphatic halogenated hydrocarbons treated with the CO₂-induced hyperventilation.

Case	AHH intoxication; Route (amount)	Selected case details of 52 patients under CO2-induced hyperventilation
1. Male, 46 years	Dichloromethane; Ingestion (45 mL)	Intentional ingestion with subsequent vomiting. Awake at admission. Clinically lacking signs of toxicity with good outcome.
2. Male, 49 years	Dichloromethane; Inhalation (20 mL)	Accidental inhalation. No narcosis. No apparent clinical toxicity.
3. Female, 50 years	Dichloromethane; Ingestion (40 mL)	Unintentional ingestion with subsequent self-induced vomiting. Dizziness. Subsequent uneventful clinical course.
4. Male, 21 years	Chloroform; Ingestion (50 mL)	Following consumption of beer (1.5 L), unintentional ingestion of chloroform. Seizures. Narcosis requiring endotracheal intubation for gastrointestinal lavage and short-term artificial ventilation.
5. Female, 51 years	Chloroform; Ingestion (10 mL)	Unintentional ingestion of chloroform. Lack of clinical toxicity.
6. Male, 15 years	CCl4; Ingestion (30 mL)	Patient swallowed CCl4 intentionally and experienced vomiting twice. On day 3 after intoxication, serum activities of liver enzymes slightly increased, reached a maximum on day 4, and normalized until day 14 after intoxication. Liver biopsy on day 13 showed no abnormalities.
7. Female, 14 years	CCl4; Ingestion (10–20 mL)	Intentional ingestion of CCl4 accessed from a dry cleaning business where her mother was employed. She was fully oriented. Liver histology at termination of the hyperventilation therapy showed no overt liver cell necrosis but severe microvesicular fatty liver in 80–90% of the liver cells. By electron microscopy, cristae of mitochondria were reduced and disorganized. Within the mitochondria, crystalline inclusion bodies were found. At discharge all laboratory values were in the normal range.
8. Male, 31 years	CCl4; Ingestion (50 mL)	Patient intentionally swallowed CCl4 and was found by his mother. After initial treatment in a local hospital and recurrent vomiting, his clinical course was uneventful, except for a short increase of serum AST and ALT activities during days 3 and 5 after ingestion.
9. Male, 70 years	CCl4; Ingestion (∼50 mL)	Patient unintentionally ingested CCl4 contained in a bottle labeled erroneously as lemonade. He was sleepy and experienced diarrhea with black-colored stools, with later recurrent vomiting also. Peak serum activities for AST and ALT were observed on day 7 after ingestion.
10. Male, 40 years	CCl4; Ingestion (100 mL)	Following intentional ingestion of CCl4, the somnolent patient received short-term endotracheal intubation for initiating CO2-induced hyperventilation during transport via plane. Maximum values for serum activities of AST and ALT were observed on day 4 after ingestion, associated with an increase of serum creatinine. Liver histology on day 14 after ingestion revealed moderate centrilobular microvesicular fatty liver with low liver cell necrosis. Electron microscopy showed a striking proliferation and pronounced dilatation of the smooth endoplasmic reticulum of the hepatocytes. These dilated cisterns contained small membrane vortexes, similar to myelin. In the cytoplasm, vacuoles predominated. Mitochondria were enlarged and showed degeneration and vacuoles. Microvilli presented with injurious irregularities. Abnormal laboratory results returned to normal values rapidly.
11. Female, 50 years	CCl4; Inhalation (∼10 mL)	Unintentional intoxication was by inhalation of CCl4, which the patient used for cleaning of a spot on her carpet. She experienced nausea for a day and had a blood ethanol level of 1.77. Under hyperventilation therapy, serum activities of AST and ALT remained virtually unchanged.
12. Female, 50 years	CCl4; Ingestion (∼50 mL)	Patient unintentionally swallowed CCl4 contained in a mineral water bottle and vomited intentionally. Symptoms included severe headaches and nausea. Peak enzyme activities were determined for serum AST and ALT 4 days after ingestion, with retarded decline and normalization.
13. Male, 36 years	CCl4; Ingestion (50 mL)	Patient intentionally ingested CCl4 and consumed beer (∼2.5 Liter) and hard liquor (∼0.5 Liter). At admission, his blood ethanol was 2.5–3.0. On day 3 after ingestion, a peak activity was observed for AST and AST, with subsequent decline. Serum total bilirubin and creatinine increased steadily. Endotracheal intubation, dialysis, and two reanimations were required. Complications included acute liver failure, pneumonia, and respiratory insufficiency, leading to a fatal outcome.
14. Female, 22 years	CCl4; Inhalation (∼50 mL)	Intentional inhalation of CCl4 led to nausea, stomach cramps, tachycardia, and intermittent somnolence. Prompted decline of initially increased serum activities of ALT and AST.
15. Male, 33 years	CCl4; Inhalation (amount?)	As a conservator and owner of a business for restoring oil paintings and art work, the patient unintentionally inhaled CCl4 for several days, a typical occupational intoxication. Symptoms included loss of appetite, nausea, vomiting, headaches and pains in the neck. Throughout the clinical course, values of serum total bilirubin and creatinine remained in the normal range. Previous alcohol use of 0.7 Liter wine and 0.2 Liter beer daily was considered as risk factor of the liver toxicity by CCl4. On day 5 after admission, liver histology showed a moderate steatosis with small and large fat droplets as well as some inflammation but no necrosis. By electron microscopy, the mitochondria were swollen and their cristae were reduced. Abundant bile pigments were seen between the nucleus and bile canaliculus. Initially increased serum activities for AST and ALT normalized rapidly.
16. Female, 29 years	CCl4; Inhalation (amount?)	Patient unintentionally inhaled CCl4 for 4–5 weeks under similar working conditions as described for Patient 15 above, in whose business she was employed as conservator. Symptoms included malaise, loss of appetite, fever, dark urine, flu-like joint pains and back pains. Her alcohol use was quantified as 2 Liter wine per week. Liver histology obtained 3 days after cessation of the hyperventilation therapy showed in zone 3 a mild steatosis involving 20–30% of the hepatocytes, severe single cell necrosis, and a moderate activation of hepatic stellate cells. The clinical course was complicated by oliguric renal insufficiency, treated with forced diuresis. The initially increased serum activities of AST and ALT normalized until day 11.
17. Male, 31 years	CCl4; Inhalation (amount?)	Patient unintentionally inhaled CCl4 and had worked together with Patients 15 and 16 above in the business of Patient 15 above and under similar working conditions. Symptoms included nausea, headaches, joint pains, lower back pains, sore throat, dark urine, vomiting and diarrhea. Via a university hospital, he was transferred by helicopter, together with Patient 11, to our Intensive Care Unit. He showed beginning withdrawal symptoms, likely related to his alcohol use which was reported as 2.5 Liter beer daily and occasionally more. Initially increased serum activities of AST and ALT normalized within 17 days. Liver histology obtained 39 days after the last CCl4 exposure showed a low-grade fatty liver and residues of a toxic event. Complications included basal pneumonia, respiratory insufficiency requiring O2 application, and renal insufficiency requiring intermittent hemodialysis on 12 days. Discharge was possible after 42 days in fairly good condition. This case, as well as the 2 cases above, had been reported to the respective trade association.
18. Male, 37 years	1,2-Dichloroethane; Ingestion (15 mL)	Accidental ingestion, vomiting. During weekends, 1.0 – 1.5 Liter beer. Marginally increased serum activities of AST and ALT.
19. Male, 40 years	1,2-Dichloroethane; Ingestion (15–20 mL)	Unintentional uptake. No symptoms at admission. Minimally increased serum activities of AST and ALT.
20. Male, 16 years	1,2-Dichloroethane; Ingestion (∼50 mL)	Intentional ingestion. Gastrointestinal lavage in the local hospital. Serum activities of AST and ALT remained in the normal range.
21. Female, 24 years	1,2-Dichloroethane; Ingestion (7 mL)	Accidental ingestion. Normal serum AST and ALT.
22. Male, 48 years	1,2-Dichloroethane; Ingestion (5 mL)	Unintentional ingestion. Vomiting, subsequent nausea. Serum activities of AST and ALT were slightly increased.
23. Male, 44 years	1,2-Dichloroethane; Ingestion (25 mL)	Accidental uptake, self-induced vomiting followed by spontaneous vomiting, nausea. Superficial ulceration of the tongue. Slightly increased serum values of AST and ALT.
24. Female, 17 years	1,2-Dichloroethane; Ingestion (40 mL)	Intentional ingestion, with 100 mg medazepam and 1.0 L beer. Recurrent vomiting. Transfer by helicopter. Small increases of serum AST and ALT activities.
25. Male, 46 years	1,2-Dichloroethane; Ingestion (5 mL)	Accidental ingestion, vomiting. Uneventful clinical course with normal serum activities of AST and ALT.
26. Male, 78 years	1,2-Dichloroethane; Ingestion (35 mL)	Unintentional ingestion after alcohol use. Vomiting and nausea. Cautious CO2-induced hyperventilation for 5 days, premature cessation due to COPD. Slight increases of AST and ALT activities.
27. Male, 37 years	1,2-Dichloroethane; Ingestion (35 mL)	Unintentional ingestion, vomiting. Gastrointestinal lavage. Virtually normal serum AST and ALT activities.
28. Male, 34 years	1,2-Dichloroethane; Ingestion (15 mL)	Accidental ingestion. Gastrointestinal lavage in local hospital. Slightly increased serum activities of AST and ALT.
29. Male, 35 years	1,2-Dichloroethane; Ingestion (25 mL)	Unintentional ingestion, vomiting several times. Transfer by helicopter. Dizziness and nausea. Slightly increased serum activities of AST and ALT.
30. Female, 18 years	1,2-Dichloroethane; Ingestion (80 mL)	Intentional ingestion, vomiting at home. Minimally increased serum activities of AST and ALT.
31. Female, 57 years	1,2-Dichloroethane; Ingestion (50 mL)	Intentional ingestion, then vomiting, and gastrointestinal lavage. Moderate alcohol use. Under hyperventilation therapy, normal AST and ALT.
32. Female, 79 years	1,2-Dichloroethane; Inhalation (∼8 mL)	Unintentional inhalation with usual treatment thereafter. Marginally increased serum activities of AST and ALT.
33. Male, 32 years	1,2-Dichlorethane; Inhalation (∼6 mL)	Unintentional inhalation for 2 hours. Vomiting and nausea. Minimally increased serum activities of AST and ALT.
34. Female, 81 years	1,2-Dichloroethane Ingestion (20 mL)	Unintentional ingestion, immediate vomiting and later short somnolence. Gastrointestinal lavage. Single defibrillation for cardiac ventricular flutter. Under therapy, virtually normal serum activities of AST and ALT.
35. Female, 21 year	1,2-Dichloroethane; Ingestion (35 mL)	Intentional intake, with prior ingestion of 20 mL hard liquor. Vomiting. Gastrointestinal lavage. Serum activities of AST and ALT remained normal.
36. Female, 20 years	1,1,2-Trichloroethane; Ingestion (100 mL)	Intentional ingestion, together with oxaxepam (20 tablets). Narcosis. Systemic seizures. Vomiting and nausea. ECG: significant extrasystoles. Acrocyanosis. Rapid start of CO2-induced hyperventilation. Serum activities of AST and ALT remained normal.
37. Male, 19 years	1,1,2-Trichloroethane; Ingestion (unknown amount)	Intentional ingestion, also of temazepam (340 mg). Found unconscious. For 4 days, initial treatment in a local hospital, gastrointestinal lavage. At transfer, intubated, moribund, and death the other day. Forced diuresis. Artificial ventilation. Before death, maximum serum activities: AST 1870 U/L, ALT 2950 U/L.
38. Male, 49 years	Trichloroethylene; Ingestion (40 mL)	Unintentional ingestion. Vomiting, diarrhea. Dizziness. Transfer by airplane and start, on board, with CO2-induced hyperventilation, which was continued for 4 days and caused undetectable blood levels of the AHH and virtually normal serum activities of AST and ALT.
39. Male, 50 years	Trichloroethylene; Ingestion (100 mL)	Unintentional ingestion. Narcosis. Transport by airplane, narcosis receded. Incipient pneumonia. Serum activities of AST and ALT remained in the normal range.
40. Male, 55 years	Trichloroethylene; Ingestion (50 mL)	Accidental ingestion. Preexisting AFLD, presently reduced alcohol use. Dizziness. Slightly increased serum activities of AST and ALT.
41. Male, 16 years	Trichloroethylene; Ingestion (300 mL)	Intentional ingestion. Narcosis. Marginally increased serum activities of AST and ALT.
42. Male, 18 years	Trichloroethylene; Ingestion (>10 mL)	Unintentional ingestion after drinking 1.0 L beer. Nausea, narcosis. Slightly increased serum activities of AST and ALT.
43. Male, 67 years	Trichloroethylene; Ingestion (30 mL)	Accidental ingestion. Following gastrointestinal lavage and under CO2-induced hyperventilation, serum activities of AST and ALT remained normal.
44. Male, 49 years	Trichloroethylene; Ingestion (90 mL)	Intentional ingestion together with Stroh rum. Known alcohol abuse. Vomiting, narcosis, endotracheal intubation, subsequent gastrointestinal lavage. Suspected shock in lungs, artificial ventilation combined with CO2-induced hyperventilation, whereby CO2 was added to the inspiration air. Serum activities of AST and ALT moderately increased at admission, thereafter rapid normalization.
45. Male, 17 years	Trichloroethylene; Ingestion (70 mL)	Unintentional ingestion. Somnolence. Vomiting. Normal serum AST and ALT activities.
46. Male, 26 years	Trichloroethylene; Ingestion (100 mL)	Intentional ingestion. Alcohol abuse. Vomiting. Narcosis. Transfer by plane. Serum activities of AST and ALT remained in normal range.
47. Female, 20 years	Trichloroethylene; Ingestion (100 mL)	Intentional ingestion, together with diclofenac (1.0 g), hydrochlorothiazide (1.5 g), and acetyl salicylic acid (5.6 g). Narcosis, endotracheal intubation. After transfer, start with hyperventilation by means of a respirator and adding CO2 to the inspiration mixture, which reduced serum trichloroethylene levels from >1 mg/mL down to 1 μg/mL. Serum activities of AST and ALT remained normal. The clinical course was fatal due to respiratory insufficiency and complications, ascertained by autopsy: Purulent trachea-bronchitis, pneumonia, and congestion of the liver.
48. Male, 28 years	Trichloroethylene; Ingestion (>500 mL)	Intentional ingestion. Spontaneous and later self-induced vomiting. Narcosis. Serum activities of AST and ALT remained in the normal range.
49. Male, 49 years	Trichloroethylene; Ingestion (700 mL)	Intentional ingestion. Somnolence. Became wet, fecal leakage. Known alcohol abuse. Marginally increased serum activities of AST and ALT.
50. Female, 40 years	Trichloroethylene; Ingestion (200 mL)	Intentional ingestion. Narcosis, fecal leakage. Minimally increased activities of AST and ALT.
51. Male, 51 years	Tetrachloroethylene; Ingestion (160 mL)	Accidental ingestion. Dizziness. Self-induced vomiting. Transfer by helicopter. Serum activities of AST and ALT remained normal.
52. Male, 61 years	Tetrachloroethylene; Ingestion (500 mL)	Intentional ingestion. Narcosis. Complicated clinical course with aspiration pneumonia. Minimally increased serum activities of AST and ALT.

Case data are presented in condensed form. For listed patients with intoxications by CCl₄, many additional data of interest are available, though not included in this table; the data had been reported previously in a recent publication.16 For all patients with intoxication by ingestion of AHH, treatment was commonly initiated in the local hospital by gastrointestinal lavage, sometimes already. Intoxicated patients by ingestion or inhalation all received the CO₂-induced hyperventilation therapy, whereby CO₂ was provided via nasal tube and rarely via an oxygen mask. A few patients required endotracheal intubation and received CO₂ together with the inspiration air. Treatment was provided as outlined (Table 1).

Abbreviations: AFLD, alcoholic fatty liver disease: ALT, alanine transaminase; AST, aspartate transaminase; CCl₄, carbon tetrachloride; COPD, chronic obstructive pulmonary disease.