Risk of recurrent venous thromboembolism and major hemorrhage in cancer-associated incidental pulmonary embolism among treated and untreated patients: a pooled analysis of 926 patients

ESSENTIALS: We performed a pooled analysis of 926 patients with cancer-associated incidental pulmonary embolism (IPE). Vitamin K antagonists (VKA) are associated with a higher risk of major hemorrhage. Recurrence risk is comparable after subsegmental and more proximally localized IPE. Our results support low molecular weight heparins over VKA and similar management of subsegmental IPE.

BACKGROUND

Incidental pulmonary embolism (IPE) is defined as pulmonary embolism (PE) diagnosed on computed tomography scanning not performed for suspected PE. IPE has been estimated to occur in 3.1% of all cancer patients and is a growing challenge for clinicians and patients. Nevertheless, knowledge about the treatment and prognosis of cancer-associated IPE is scarce. We aimed to provide the best available evidence on IPE management.

METHODS

Incidence rates of symptomatic recurrent venous thromboembolism (VTE), major hemorrhage, and mortality during 6-month follow-up were pooled using individual patient data from studies identified by a systematic literature search. Subgroup analyses based on cancer stage, thrombus localization, and management were performed.

RESULTS

In 926 cancer patients with IPE from 11 cohorts, weighted pooled 6-month risks of recurrent VTE, major hemorrhage and mortality were 5.8% (95% confidence interval [CI] 3.7-8.3%), 4.7% (95% CI 3.0-6.8%), and 37% (95% CI 28-47%). VTE recurrence risk was comparable under low molecular weight heparins (LMWH) and vitamin K antagonists (VKAs) (6.2% vs. 6.4%; hazard ratio [HR] 0.9; 95% CI 0.3-3.1), while 12% in untreated patients (HR 2.6; 95% CI 0.91-7.3). Risk of major hemorrhage was higher under VKAs than under LMWH (13% vs. 3.9%; HR 3.9; 95% CI 1.6-10). VTE recurrence risk was comparable in patients with an subsegmental IPE and those with a more proximally localized IPE (HR 1.1; 95% CI 0.50-2.4).

CONCLUSION

These results support the current recommendation to anticoagulate cancer-associated IPE with LMWH and argue against different management of subsegmental IPE.

Pulmonary hypertension in patients with chronic myeloproliferative disorders

Pulmonary hypertension (PH) is a severe haemodynamic disorder in which the pulmonary artery pressure is persistently elevated, leading to right-sided heart failure and death. Recently, chronic myeloproliferative diseases associated with pulmonary hypertension were included in the group 5 category, corresponding to PH for which the aetiology is unclear and/or multifactorial. In this review we will describe the distinct forms of PH in the context of the myeloproliferative diseases chronic thromboembolic pulmonary hypertension and pre-capillary PH mimicking pulmonary arterial hypertension. The epidemiology, mechanisms and treatment approaches will be discussed.

Optimal oxygen pressure and time for reduced bubble formation in theN2-saturated decompressed prawn

Bubbles that grow during decompression are believed to originate from preexisting gas micronuclei. We showed that pretreatment of prawns with 203 kPa oxygen before nitrogen loading reduced the number of bubbles that evolved on decompression, presumably owing to the alteration or elimination of gas micronuclei (Arieli Y, Arieli R, and Marx A. J Appl Physiol 92: 2596–2599, 2002). The present study examines the optimal pretreatment for this assumed crushing of gas micronuclei. Transparent prawns were subjected to various exposure times (0, 5, 10, 15, and 20 min) at an oxygen pressure of 203 kPa and to 5 min at different oxygen pressures (Po2 values of 101, 151, 203, 405, 608, and 810 kPa), before nitrogen loading at 203 kPa followed by explosive decompression. After the decompression, bubble density and total gas volume were measured with a light microscope equipped with a video camera. Five minutes at a Po2 of 405 kPa yielded maximal reduction of bubble density and total gas volume by 52 and 71%, respectively. It has been reported that 2–3 h of hyperbaric oxygen at bottom pressure was required to protect saturation divers decompressed on oxygen against decompression sickness. If there is a shorter pretreatment that is applicable to humans, this will be of great advantage in diving and escape from submarines.

Effects of nitrogen and helium on CNS oxygen toxicity in the rat

The contribution of inert gases to the risk of central nervous system (CNS) oxygen toxicity is a matter of controversy. Therefore, diving regulations apply strict rules regarding permissible oxygen pressures (Po(2)). We studied the effects of nitrogen and helium (0, 15, 25, 40, 50, and 60%) and different levels of Po(2) (507, 557, 608, and 658 kPa) on the latency to the first electrical discharge (FED) in the EEG in rats, with repeated measurements in each animal. Latency as a function of the nitrogen pressure was not homogeneous for each rat. The prolongation of latency observed in some rats at certain nitrogen pressures, mostly in the range 100 to 500 kPa, was superimposed on the general trend for a reduction in latency as nitrogen pressure increased. This pattern was an individual trait. In contrast with nitrogen, no prolongation of latency to CNS oxygen toxicity was observed with helium, where an increase in helium pressure caused a reduction in latency. This bimodal response and the variation in the response between rats, together with a possible effect of ambient temperature on metabolic rate, may explain the conflicting findings reported in the literature. The difference between the two inert gases may be related to the difference in the narcotic effect of nitrogen. Proof through further research of a correlation between individual sensitivity to nitrogen narcosis and protection by N(2) against CNS oxygen toxicity in rat may lead to a personal O(2) limit in mixed-gas diving based on the diver sensitivity to N(2) narcosis.

Transient osteoporosis associated with hyperhomocystinemia: a possible role for hyperbaric oxygen therapy

Transient osteoporosis of the hip is considered by some to be an early stage of avascular necrosis. Hyperbaric oxygen (HBO2) therapy, which may be of benefit in the treatment of avascular necrosis, might therefore be used in the treatment of transient osteoporosis of the hip. We present a case of transient osteoporosis associated with elevated levels of homocysteine in a 33-year-old white male, who was treated by HBO2. Treatment was administered at 2.5 ATA for 90 minutes once daily, five days per week. Regular follow-up examinations in the course of the HBO2 therapy revealed improvement in the patient's complaints and the findings of the physical examination. Repeated magnetic resonance imaging (MRI) performed after 40 and 90 sessions showed decreased edema and complete resolution of the edema, respectively. Evaluation 6 months after the completion of treatment revealed complete resolution of symptoms, with a normal physical examination.

Early hyperbaric oxygen therapy for retinal artery occlusion

PURPOSE

To assess whether early hyperbaric oxygenation (HBO) treatment has a beneficial effect on visual results after retinal artery occlusion (RAO).

METHODS

A comparative retrospective study in which medical records of all HBO-treated RAO patients in our department were reviewed and compared with matched RAO patients not treated by HBO (from a different medical center). Mean visual acuity (VA) at completion of treatment, the presence or absence of improvement in VA between admission and discharge, and the mean change in VA between admission and discharge were noted. All patients treated by HBO had treatment no later than 8 hours after the beginning of visual symptoms.

RESULTS

Mean VA at discharge was 0.2981 (6/20) in the treated group and 0.1308 (6/46) in the control group (p < 0.03). In the treated group, 82.9% had an improvement in VA between admission and discharge, compared with 29.7% of the control group (p < 0.00001). Mean improvement in VA was 0.1957 in the treated group and 0.0457 in the control group (p < 0.01). Differences in outcome measures between treatment and control groups were found to reflect the difference between treated and untreated hypertensive patients. No difference was found between treated and untreated non-hypertensive patients.

CONCLUSIONS

Early HBO therapy appears to have a beneficial effect on visual outcome in patients with RAO. Further large-scale prospective controlled studies are needed to confirm this.

Pulmonary oedema induced by strenuous swimming: a field study

The purpose of the study was to document the incidence and recurrence rate of pulmonary oedema induced by strenuous swimming (SIPO), and to study the changes in relevant physiological parameters. Thirty-five young men were repeatedly examined over a 2-month period after a swimming time trial in the open sea. A tentative diagnosis of SIPO was made when the swimmer reported shortness of breath accompanied by cough. Twenty-nine events of SIPO were diagnosed in 21 individuals (60% incidence). Oxygen saturation was significantly reduced in SIPO. Mean forced vital capacity (FVC) and FEV(1) were significantly lower in the severe SIPO group. Also, mean FVC and mid-expiratory flows (FEF(25-75%)) obtained 12 months earlier during screening for the programme were lower in individuals who later had SIPO. The ratios of post-swim FVC and FEV(1) values to the corresponding selection examination values were lower in the severe SIPO group. Thus volumes decreased in the SIPO group, besides being lower at the start. Shortness of breath and coughing following strenuous swimming were related to hypoxaemia and reduction in lung volumes, suggesting pulmonary oedema. SIPO was a common and often recurrent phenomenon. Lower initial lung volumes and flows might predict future susceptibility to SIPO.

[Decompression sickness in divers treated at the Israel Naval Medical Institute between the years 1992 to 1997]

Clinical characteristics of 125 divers treated for decompression sickness (DCS) in the hyperbaric multiplace chambers of this Institute during 1992-1997 were analyzed retrospectively. In 62 (51%) the diagnosis was DCS Type I (joint pain or skin involvement) and in 60 (49%) DCS Type II (neurological, inner ear or pulmonary disease). Risk factors for the evolution of DCS were depth and duration of the dives involving accidents, violation of recommendations of the decompression tables, and repeated dives. Results were available for 112 of the 125 patients. 54 of them (48%) recovered completely, and another 54 recovered partially; 4 did not respond to treatment. Inner ear DCS was less responsive to hyperbaric oxygen treatment (p = 0.0001). There was significant improvement of neurological function in those with severe neurological injury (p = 0.0001). Rapid diagnosis and transportation of divers with DCS to a hyperbaric chamber is of crucial importance.

A transgenic insertional inner ear mutation on mouse chromosome 1

OBJECTIVES/HYPOTHESIS

To clone and characterize the integration site of an insertional inner ear mutation, produced in one of fourteen transgenic mouse lines. The insertion of the transgene led to a mutation in a gene(s) necessary for normal development of the vestibular labyrinth.

STUDY DESIGN

Molecular genetic analysis of a transgene integration site.

METHODS

Molecular cloning, Southern and northern blotting, DNA sequencing and genetic database searching were the methods employed.

RESULTS

The integration of the transgene resulted in a dominantly inherited waltzing phenotype and in degeneration of the pars superior. During development, inner ear fluid homeostasis was disrupted. The integration consisted of the insertion of a single copy of the transgene. Flanking DNA was cloned, and mapping indicated that the genomic DNA on either side of the transgene was not contiguous in the wild-type mouse. Localization of unique markers from the two flanks indicated that both were in the proximal region of mouse chromosome 1. However, in the wild-type mouse the markers were separated by 6.3 cM, indicating a sizable rearrangement. Analysis of the mutant DNA indicated that the entire region between the markers was neither deleted nor simply inverted.

CONCLUSIONS

These results are consistent with a complex rearrangement, including at least four breakpoints and spanning at least 6.3 cM, resulting from the integration of the transgene. This genomic rearrangement disrupted the function of one or more genes critical to the maintenance of fluid homeostasis during development and the normal morphogenesis of the pars superior.

The effect of low-frequency ultrasound on immersed pig lungs

Acoustic models suggest that high-intensity, low-frequency ultrasound (US) at 21-31 kHz, could cause damage to divers' lungs. The purpose of the study was to investigate lung tissue changes secondary to water-borne low-frequency US produced by commonly used underwater acoustic beacons (pingers). Explanted pig lungs were immersed and exposed to four different modes of low-frequency US pinger transmission. In each trial, 5 pairs of lungs were exposed to sound and 5 pairs served as controls. One central and one peripheral section were taken from each lung and evaluated microscopically for location and extent of damage. When present, microhaemorrhages were primarily found in a patchy alveolar distribution, as well as in the septal and subpleural regions. Only rare focal microhaemorrhages could be found in the Control Group. The results demonstrate a potential hazard to the immersed lungs of large mammals on exposure to prolonged transmission by commercially available underwater pingers. The relevance of these findings to human exposure should be further evaluated.

Effects of exposure to low concentrations of carbon monoxide on exercise performance and myocardial perfusion in young healthy men

OBJECTIVE

To assess the effects of exposure to low concentrations of carbon monoxide (CO), as commonly measured in atmospheric urban air pollution and certain occupational environments, on exercise performance and myocardial perfusion in young healthy men, and the possible need for tighter restrictions on ambient concentrations of CO.

METHODS

15 young, healthy non-smoking men, 18-35 years old, were exposed blindly and randomly to air or to a mixture of CO and air, followed by an exercise treadmill test with thallium heart scintigraphy. Blood was drawn for determination of carboxyhaemoglobin before and at the end of the exposure, and for lactic and pyruvic acid at the beginning and the end of the exercise test. The main outcome measures include the duration of the exercise test, the maximal effort expressed in metabolic equivalent units (METs), the mean plasma lactic to pyruvic acid ratio at the end of the ergometry, ECG changes in the exercise test, and perfusion deficits in thallium heart scintigraphy.

RESULTS

At the end of exposure to CO, the mean (SD) blood carboxyhaemoglobin concentration rose from 0.59% (0.08%) to 5.12% (0.65%) (p < 0.0001). At the end of the exercise period, the mean (SD) plasma lactate/pyruvate ratio, which reflects the level of anaerobic metabolism (69.9 (5.9) after air and 75.9 (7.0) after CO), was not significantly different between the two experimental groups. Exercise induced electrocardiographic changes were noted in only one subject after exposure to CO. No arrhythmias were detected in any of the subjects. Significant differences were found in the mean duration of the exercise test (p = 0.0012) and the METs (p = 0.0001). The mean adjusted difference of exercise duration between exposure to air and CO was 1.52 minutes 95% confidence interval (95% CI) 0.73 to 2.32 minutes. The mean adjusted difference of METs between exposure to air and CO was 2.04 95% CI 1.33 to 2.76. The models for duration of exercise and METs showed no significant sequence and period effects. Thallium myocardial perfusion imaging disclosed normal perfusion in all regions of the heart, with no significant differences in perfusion between the two exercise tests (after air or CO).

CONCLUSION

Acute exposure to a low concentration of CO which produces blood carboxyhaemoglobin concentrations of 4%-6% significantly decreases exercise performance in young healthy men. No ischaemic electrocardiographic changes or disturbances in myocardial perfusion were found by graded exercise with thallium scintigraphy. Our findings suggest that pollution of atmospheric air by CO at concentrations which are commonly found in urban and industrial environments may exert an adverse effect on skeletal muscles, manifesting as decreased exercise performance.

Hyperbaric oxygen therapy for massive arterial air embolism during cardiac operations

BACKGROUND

Massive arterial air embolism is a rare but devastating complication of cardiac operations. Several treatment modalities have been proposed, but hyperbaric oxygen is the specific therapy.

METHODS

The Israel Naval Medical Institute is the only referral hyperbaric center in this country for acute care patients. We reviewed our experience in the hyperbaric oxygen treatment of massive arterial air embolism during cardiac operations.

RESULTS

Seventeen patients were treated between 1985 and 1998. Eight patients (47.1%) experienced a complete neurologic recovery; 6 patients (35.3%) remained unconscious at discharge, and 3 patients (17.6%) died. Mean (+/- SD) delay from the end of the operation to hyperbaric therapy was 9.6 +/- 7.4 hours (range, 1-20 hours). This delay was 4.0 +/- 3.4 hours (1-12 hours) for patients who had a full neurologic recovery, 12.8 +/- 7.1 hours (5-20 hours) for patients with severe neurologic disability, and 18.0 +/- 2.0 hours (16-20 hours) for patients who died (1-way analysis of variance; P =.002). The source of variance among the groups mainly resulted from the short delay for patients who experienced complete recovery compared with the other 2 groups (Tukey test). All 5 patients who were treated within 3 hours from the operation and 50% (2 of 4 patients) of those patients treated 3 to 5 hours from operation experienced a full neurologic recovery. With a delay of 9 to 20 hours, only 1 of 8 patients had a full neurologic recovery. The association between outcome and treatment delay was found to be statistically significant (tau = 0.65 with exact 2-sided P value =.0007).

CONCLUSION

Hyperbaric oxygen therapy should be administered as soon as possible after massive arterial air embolism during cardiac operations.

Effects on pulmonary function of daily exposure to dry or humidified hyperbaric oxygen

The purpose of this study was to examine the effects of breathing dry or humidified hyperbaric oxygen on pulmonary function. Pulmonary function tests were performed before and after each of 10 hyperbaric oxygen exposures at 2.5 atmospheres absolute (ATA) for 95 min in a group of 13 patients treated daily by hyperbaric oxygen for problem wounds. Patients breathed dry oxygen during five successive sessions and humidified oxygen during the remaining five. No differences were found between forced vital capacities (FVC) and maximal expiratory flows before and after hyperbaric oxygen exposure while breathing dry or humidified oxygen. Significant differences were found for the changes in the percentage of FVC expired in 1 s (FEV1%) and mean forced mid-expiratory flow rate during the middle half of the FVC (FEF25-75%) on day 1 alone: decrements of 1.42 and 2.96%, respectively, under dry oxygen, vs. increments of 3.93 and 34.4%, respectively, for humidified oxygen. Day-to-day decrements in the percent changes in FEV1% and FEF25-75% were observed while breathing humidified hyperbaric oxygen. These results demonstrate that repeated daily exposure to humidified hyperbaric oxygen abolishes the initial beneficial effect of humidification on peripheral airways flow characteristics.

Modification of in vivo and in vitro TNF-alpha, IL-1, and IL-6 secretion by circulating monocytes during hyperbaric oxygen treatment in patients with perianal Crohn's disease

Treatment of perianal inflammatory lesions in Crohn's disease (CD) is unsatisfactory and novel treatment modalities are pursued. We have recently reported a good clinical effect of hyperbaric oxygen (HBO) treatment in perianal CD. In the present study, seven patients with perianal CD were subjected to daily sessions of HBO in a multiplace hyperbaric chamber. Each patient received a total of 20 sessions during a time period of 1 month, and IL-1, IL-6, and TNF-alpha measurements were done several times during the initial sessions and after completing therapy. Pretreatment cytokine levels were elevated in patients compared to age-matched 10 normal controls. During the first 7 days of treatment, IL-1, IL-6, and TNF-alpha levels in supernatants of LPS-stimulated monocytes derived from patients' peripheral blood were decreased compared to pretreatment levels. Parallel measurements of serum IL-1 levels revealed an initial elevation and thereafter decreased levels, which remained low throughout the first week of HBO treatment. After completion of therapy, cytokine levels increased to pretreatment values. We conclude that alterations in secretion of IL-1, IL-6, and TNF-alpha may be related to the good clinical effect of HBO treatment in CD patients with perianal disease.

Salutary consequences of oxygen therapy on the long-term outcome of hemorrhagic shock in awake, unrestrained rats

Decreased oxygen delivery and cellular hypoxia are major factors in the pathophysiology of shock. We studied the effects of 100% O2 at 0.1 and 0.3 MPa (1 and 3 atm abs) in severe hemorrhagic shock in awake, unrestrained rats. Shock was induced by withdrawing 50% of the total blood volume within 120 min. Blood pressure, heart rate, and the electroencephalogram (EEG) were recorded during the first 6 h of the protocol. The animals were observed for 7 days. The shock protocol resulted in 60 and 90% mortality after 1 day and at the end of 7 days, respectively. A single 90-min exposure to O2 at 0.1 and 0.3 MPa, which was started 30 min after bleeding, maintained mean arterial blood pressure at significantly higher values compared to untreated controls throughout the exposure period (P < 0.05). Oxygen therapy at both doses also improved the long-term survival rate and survival time significantly (P < 0.01). No clinical or EEG sign of CNS O2 toxicity was detected in O2-treated animals. Our results indicate that O2 given alone after severe bleeding exerts a beneficial effect on the long-term outcome of hemorrhagic shock in awake, unrestrained rats.

Hyperbaric oxygen for perianal Crohn's disease

Perianal involvement in Crohn's disease is common (< or = 50%), distressing, and frequently refractory to treatment. Clinical features include painful induration and stenosis, discharging fistulas, and fissures. The pathogenesis of these lesions is unclear, but local ischemia and secondary anaerobic infection may play a role. Following three sporadic reports of successful treatment with hyperbaric oxygen (HBO), we undertook a trial of this method in 10 patients with refractory perianal disease. These patients' perianal Crohn's disease had not responded to treatment that included local medications, salicylates, corticosteroids, metronidazole, or 6-mercaptopurine were treated. Treatment was administered in a hyperbaric chamber at a pressure of 2.5 atm absolute. Each session lasted 90 min, and each course consisted of 20 daily sessions. Complete healing occurred in 5 patients after one to two courses. In an additional 2, after three courses, 1 patient improved but did not heal, and 2 did not improve. No adverse effects were noted by any of the 10 patients. Follow-up of 18 months did not reveal any recurrence. These preliminary results confirm that HBO therapy is a safe and efficient therapeutic option for perianal Crohn's disease.

Spinal cord decompression sickness in sport diving

OBJECTIVE

To summarize 16 years' experience in the diagnosis and treatment of spinal cord decompression sickness in Israel.

DESIGN

The survey data were collected firsthand by physicians trained in underwater diving medicine.

SETTING

The Israeli Naval Medical Institute, Israel's national hyperbaric referral center.

PATIENTS

Sixty-eight sport divers diagnosed as having spinal cord decompression sickness.

INTERVENTIONS

Hydration and 100% oxygen breathing until the patient reached the hyperbaric chamber. All patients received recompression therapy on US Navy treatment tables using oxygen, except for six who were treated by Comex Treatment Table CX-30, which uses helium in addition to oxygen.

MAIN OUTCOME MEASURES

Neurological examination after the completion of recompression therapy.

RESULTS

Forty-one percent of the dives were performed within the decompression limits of the US Navy standard decompression tables. Risk factors were fatigue, circumstances suggesting dehydration, and extreme physical effort. The most common presenting symptoms were paresthesias, weakness of the legs, lower back pain, or abdominal pain. Full recovery was achieved in 79% of the patients. Spinal symptoms appeared immediately on surfacing in six of the eight patients who continued to have multiple neurological sequelae.

CONCLUSIONS

United States Navy air decompression tables appear not to be completely safe for sport divers. Even mild spinal symptoms identified on surfacing should be treated vigorously. High-pressure oxygen-helium therapy seems to be a promising alternative in cases of severe spinal cord decompression sickness.

Oxy-helium treatment of severe spinal decompression sickness after air diving

Spinal cord injury in DCS after air diving is relatively frequent and often has late sequelae. U.S. Navy oxygen tables are sometimes not satisfactory. The advantage of using helium in these cases is based theoretically on its physical properties and has been demonstrated in animal models. We have introduced the Comex-30 (CX-30) oxy-helium table as an integral part of our treatment protocol for severe spinal DCS. We summarize here our clinical experience with seven cases. A case was considered severe if clinical assessment suggested progressive neurologic injury to the spinal cord or roots. Except for one case, the initial treatment was CX-30 followed by HBO sessions as indicated. Of the seven patients treated, five made a full recovery and the remaining two were left with mild neurologic sequelae.

Massive air embolism--a possible cause of death after operative hysteroscopy using a 32% dextran-70 pump

Although considered a safe procedure, operative hysteroscopy has been reported to result in serious and even fatal complications. A fatal outcome is described after operative hysteroscopy. The attending team made a diagnosis of massive air embolism. However, HBO therapy, which is the specific treatment for air embolism, yielded only transient improvement. The pathologist's diagnosis on autopsy was anaphylaxis. These two complications must be borne in mind during the procedure, and a contingency plan developed for dealing with them should they arise.

[Hyperbaric oxygen for neuropsychiatric sequelae of carbon monoxide poisoning]

A broad range of neuropsychiatric abnormalities, including dementia, psychosis, and parkinsonism, as well as almost every known neurologic syndrome, can occur following carbon monoxide (CO) poisoning. These symptoms develop 2-40 days (usually 2-3 weeks), after initial exposure. There is an incidence of recurrence of up to 40%. However, in recent years the neuropsychiatric sequelae appear to have been occurring less frequently, perhaps as a direct result of the use of hyperbaric oxygen (HBO) therapy. There is no specific therapy for this complication, but up to 75% recover within 12-18 months. Myers et al. (Ann Emerg Med, 14: 1163, 1985) found HBO to be effective for the neuropsychiatric sequelae. We report a 19-year-old man who developed late psychiatric disturbances despite the use of HBO for acute CO intoxication. The neuropsychiatric symptoms, which developed 3 days after full recovery of consciousness, resolved completely when HBO therapy was reinstituted. 6 months later he was functioning normally with no neuropsychiatric symptoms.

Hyperbaric oxygen therapy for ischaemia of the hand due to intra-arterial injection of methadone and flunitrazepam

We present a case of accidental injection of oral methadone and flunitrazepam into the ulnar artery, with resultant severe ischaemia of the hand. Initial therapy consisted of systemic vasodilators, low molecular weight dextran and aspirin. When this therapy failed to produce improvement and amputation of the involved hand seemed inevitable, the patient was referred for hyperbaric oxygen (HBO) therapy. In spite of a 12 day delay in the initiation of HBO, the response was dramatic, with almost complete resolution of the ischaemic signs and symptoms. Intra-arterial injection, which is only rarely encountered in drug addicts, frequently results in severe ischaemia of an extremity, and carries with it a poor prognosis with currently accepted therapy. Given the presently reported experience and the known physiology of HBO, we conclude that HBO should be started early in the treatment of intra-arterial injection of drugs, and should also be considered following prolonged delays.

Hyperbaric oxygen treatment for carbon monoxide intoxication acquired in the sealed room during the Persian Gulf war

During the recent Persian Gulf war, the civilian population in Israel was frequently instructed to stay in sealed rooms in preparation for a possible chemical missile attack. The war broke out in mid-winter, and in many instances it was necessary to heat the rooms. The use of open fires or malfunctioning heating appliances inside sealed rooms could create ideal conditions for carbon monoxide (CO) poisoning. Six patients with CO intoxication resulting from confinement inside sealed rooms were referred for hyperbaric oxygen (HBO) treatment. Indications for HBO therapy were loss of consciousness and metabolic acidosis. The treatment protocol consisted of 90-min exposure to 100% oxygen at 2.5 atmospheres absolute (ATA), with repeated exposures when required. All patients made a full recovery. The risk of CO poisoning should be taken into consideration and should determine the selection of heating devices for future use in similar circumstances.