Multicenter Assessment of Cryoanalgesia Use in Minimally Invasive Repair of Pectus Excavatum: A 20-center Retrospective Cohort Study

OBJECTIVE

To assess the clinical implications of cryoanalgesia for pain management in children undergoing minimally invasive repair of pectus excavatum (MIRPE).

BACKGROUND

MIRPE entails significant pain management challenges, often requiring high postoperative opioid use. Cryoanalgesia, which blocks pain signals by temporarily ablating intercostal nerves, has been recently utilized as an analgesic adjunct. We hypothesized that the use of cryoanalgesia during MIRPE would decrease postoperative opioid use and length of stay (LOS).

MATERIALS AND METHODS

A multicenter retrospective cohort study of 20 US children's hospitals was conducted of children (age below 18 years) undergoing MIRPE from January 1, 2014, to August 1, 2019. Differences in total postoperative, inpatient, oral morphine equivalents per kilogram, and 30-day LOS between patients who received cryoanalgesia versus those who did not were assessed using bivariate and multivariable analysis. P value <0.05 is considered significant.

RESULTS

Of 898 patients, 136 (15%) received cryoanalgesia. Groups were similar by age, sex, body mass index, comorbidities, and Haller index. Receipt of cryoanalgesia was associated with lower oral morphine equivalents per kilogram (risk ratio=0.43, 95% confidence interval: 0.33-0.57) and a shorter LOS (risk ratio=0.66, 95% confidence interval: 0.50-0.87). Complications were similar between groups (29.8% vs 22.1, P =0.07), including a similar rate of emergency department visit, readmission, and/or reoperation.

CONCLUSIONS

Use of cryoanalgesia during MIRPE appears to be effective in lowering postoperative opioid requirements and LOS without increasing complication rates. With the exception of preoperative gabapentin, other adjuncts appear to increase and/or be ineffective at reducing opioid utilization. Cryoanalgesia should be considered for patients undergoing this surgery.

Antibiotic stewardship in the newborn surgical patient: A quality improvement project in the neonatal intensive care unit

BACKGROUND

There is significant diversity in the utilization of antibiotics for neonates undergoing surgical procedures. Our institution standardized antibiotic administration for surgical neonates, in which no empiric antibiotics were given to infants with surgical conditions postnatally, and antibiotics are given no more than 72 hours perioperatively.

METHODS

We compared the time periods before and after implementation of antibiotic protocol in an institution review board-approved, retrospective review of neonates with congenital surgical conditions who underwent surgical correction within 30 days after birth. Surgical site infection at 30 days was the primary outcome, and development of hospital-acquired infections or multidrug-resistant organism were secondary outcomes.

RESULTS

One hundred forty-eight infants underwent surgical procedures pre-protocol, and 127 underwent procedures post-protocol implementation. Surgical site infection rates were similar pre- and post-protocol, 14% and 9% respectively, (P = .21.) The incidence of hospital-acquired infections (13.7% vs 8.7%, P = .205) and multidrug-resistant organism (4.7% vs 1.6%, P = .143) was similar between the 2 periods.

CONCLUSION

Elimination of empiric postnatal antibiotics did not statistically change rates of surgical site infection, hospital-acquired infections, or multidrug-resistant organisms. Limiting the duration of perioperative antibiotic prophylaxis to no more than 72 hours after surgery did not increase the rate of surgical site infection, hospital-acquired infections, or multidrug-resistant organism. Median antibiotic days were decreased with antibiotic standardization for surgical neonates.

Neuronal serotonin regulates growth of the intestinal mucosa in mice

BACKGROUND & AIMS

The enteric abundance of serotonin (5-HT), its ability to promote proliferation of neural precursors, and reports that 5-HT antagonists affect crypt epithelial proliferation led us to investigate whether 5-HT affects growth and maintenance of the intestinal mucosa in mice.

METHODS

cMice that lack the serotonin re-uptake transporter (SERTKO mice) and wild-type mice were given injections of selective serotonin re-uptake inhibitors (gain-of-function models). We also analyzed mice that lack tryptophan hydroxylase-1 (TPH1KO mice, which lack mucosal but not neuronal 5-HT) and mice deficient in tryptophan hydroxylase-2 (TPH2KO mice, which lack neuronal but not mucosal 5-HT) (loss-of-function models). Wild-type and SERTKO mice were given ketanserin (an antagonist of the 5-HT receptor, 5-HT(2A)) or scopolamine (an antagonist of the muscarinic receptor). 5-HT(2A) receptors and choline acetyltransferase were localized by immunocytochemical analysis.

RESULTS

Growth of the mucosa and proliferation of mucosal cells were significantly greater in SERTKO mice and in mice given selective serotonin re-uptake inhibitors than in wild-type mice, but were diminished in TPH2KO (but not in TPH1KO) mice. Ketanserin and scopolamine each prevented the ability of SERT knockout or inhibition to increase mucosal growth and proliferation. Cholinergic submucosal neurons reacted with antibodies against 5-HT(2A).

CONCLUSIONS

5-HT promotes growth and turnover of the intestinal mucosal epithelium. Surprisingly, these processes appear to be mediated by neuronal, rather than mucosal, 5-HT. The 5-HT(2A) receptor activates cholinergic neurons, which provide a muscarinic innervation to epithelial effectors.

The use of recombinant tissue-type plasminogen activator in a newborn with an intracardiac thrombus developed during extracorporeal membrane oxygenation

Extracorporeal membrane oxygenation (ECMO) support is often used to support infants and children with hemodynamic or respiratory failure. One of the major obstacles of safely treating a child with ECMO is balancing the risk of hemorrhage with the potential for thrombus development. Managing thrombosis in the setting of ECMO is challenging and has no defined algorithm. The use of recombinant tissue-type plasminogen activator (tPA) for thrombolysis has been previously described in cases where thrombi have developed despite adequate anticoagulation. In such situations, the risk of hemorrhage must be carefully balanced with the benefit of dissolving the clot and reestablishing flow. We present a case of an infant who required ECMO because of severe primary pulmonary hypertension and subsequently developed a right atrial thrombus adjacent to the ECMO cannula. The patient was treated with tPA with immediate improvement but had fatal intracranial hemorrhage almost 3 days after the tPA was administered. In this report, we review the current literature on tPA use during ECMO support and suggest a rational approach.

Limb ischemia after common femoral artery cannulation for venoarterial extracorporeal membrane oxygenation: an unresolved problem

PURPOSE

Extracorporeal Life Support Organization Registry data confirm that the number of pediatric patients being supported by extracorporeal membrane oxygenation (ECMO) is increasing. To minimize the potential neurologic effects of carotid artery ligation, the common femoral artery (CFA) is frequently being used for arterial cannulation. The cannula has the potential for obstructing flow to the lower limb, thus increasing ischemia and possible limb loss. We present a single institution's experience with CFA cannulation for venoarterial (VA) ECMO and ask whether any precannulation variables correlate with the development of significant limb ischemia.

METHODS

We reviewed all pediatric patients who were supported by VA ECMO via CFA cannulation from January 2000 to February 2010. Limb ischemia was the primary variable. The ischemia group was defined as the patients requiring an intervention because of the development of lower extremity ischemia. The patients in the no-ischemia group did not develop significant ischemia. Continuous variables were reported as medians with interquartile ranges and compared using Mann-Whitney U tests. Differences in categorical variables were assessed using χ² testing (Fisher's Exact). Statistical significance was assumed at P < .05.

RESULTS

Twenty-one patients (age, 2-22 years) were cannulated via the CFA for VA ECMO. Significant ischemia requiring intervention (ischemia group) occurred in 11 (52%) of 21. In comparing the 2 groups (ischemia vs no ischemia), no clinical variables predicted the development of ischemia (Table 1). In the ischemia group, 9 (81%) of 11 had a distal perfusion catheter (DPC) placed. Complications of DPC placement included one case of compartment syndrome requiring a fasciotomy and one patient requiring interval toe amputation. Of the 2 patients in the ischemia group who did not have a DPC placed, 1 required a vascular reconstruction of an injured superficial femoral artery and 1 underwent a below-the-knee amputation. Mortality was lower in the ischemia group (27% vs 60%).

CONCLUSIONS

Limb ischemia remains a significant problem, as more than half of our patients developed it. The true incidence may not be known as a 60% mortality in the no-ischemia group could mask subsequent ischemia. Although children are at risk for developing limb ischemia/loss, no variable was predictive of the development of significant limb ischemia in our series. Because of the inability to predict who will develop limb ischemia, early routine placement of a DPC at the time of cannulation may be warranted. However, DPCs do not completely resolve issues around tissue loss and morbidity. Prevention of limb ischemia/loss because of CFA cannulation for VA ECMO continues to be a problem that could benefit from new strategies.

Post-appendectomy visits to the emergency department within the global period: a target for cost containment

BACKGROUND

Postoperative visits to the emergency department (ED) instead of the surgeon's office consume enormous cost.

HYPOTHESIS

Postoperative ED visits can be avoided.

SETTING

Fully accredited, single-institution, 617-bed hospital affiliated with the University of Connecticut School of Medicine.

PATIENTS

Retrospective analysis of 597 consecutive patients with appendectomies over a 4-year period.

METHODS

Demographic and medical data, at initial presentation, surgery, and ED visit were recorded as categorical variables and statistically analyzed (Pearson chi(2) test, Fisher exact test, and linear-by-linear). Costs were calculated from the hospital's billing department.

RESULTS

Forty-six patients returned to the ED within the global period with pain (n = 22, 48%), wound-related issues (n = 6, 13%), weakness (n = 4, 9%), fever (13%), and nausea and vomiting (n = 3, 6%). Thirteen patients (28%) required readmission. Predictive factors for ED visit postoperatively were perforated appendicitis (2-fold increase over uncomplicated appendicitis) and comorbidities (cardiovascular or diabetes). The cost of investigations during ED visits was $55,000 plus physician services.

CONCLUSIONS

ED visits during the postoperative global period are avoidable by identifying patients who may need additional care; improving patient education, optimizing pain control, and improving patient office access.

Laparoscopic excision of choledochal cysts with total intracorporeal reconstruction

PURPOSE

There are numerous published reports of laparoscopic resection of choledochal cysts (CDCs), but almost all involve extracorporeal reconstruction of a biliary drainage system. We describe and evaluate the technique of laparoscopic CDC resection with total intracorporeal reconstruction.

METHODS

We reviewed all patients who underwent a laparoscopic CDC resection from March 2005 to January 2010 at Rocky Mountain Children's Hospital and Children's Hospital of New York-Presbyterian. We obtained data on operative time, characteristics of reconstruction, time to initiation of diet, length of stay, complications, and outcome.

RESULTS

Thirteen patients (median age 5 years, range 1-16) underwent a laparoscopic CDC excision with total intracorporeal reconstruction. Four ports were used in all cases and no patients required conversion to an open procedure. Operative time ranged from 130 to 325 minutes (median 240 minutes). Median time to initiation of diet was 1 day (range 1-4 days). Median length of stay was 5 days (range 4-8 days). There were no cases of cholangitis; however, 1 patient developed a small bowel obstruction requiring re-operation.

CONCLUSION

Laparoscopic resection of CDCs with total intracorporeal reconstruction is a safe and effective technique. The minimal handling of the bowel appears to minimize postoperative ileus, allows for early postoperative feeding and discharge.

Spirometry testing standards in spinal cord injury

STUDY OBJECTIVES

Because muscle paralysis makes it uncertain whether subjects with spinal cord injury (SCI) can perform spirometry in accordance with American Thoracic Society (ATS) standards, determinants of test failure were examined.

DESIGN

Cross-sectional study.

SETTING

Veterans Affairs (VA) medical center.

PARTICIPANTS

Veterans with SCI at VA Boston Healthcare System and nonveterans recruited by mail and advertisement.

MEASUREMENTS AND RESULTS

Two hundred thirty of 278 subjects (83%) were able to produce three expiratory efforts lasting > or = 6 s and without excessive back-extrapolated volume (EBEV). In 217 of 230 subjects (94%), FVC and FEV(1) were each reproducible in accordance with 1994 ATS standards. In the remaining 48 subjects, efforts with smooth and continuous volume-time tracings and acceptable flow-volume loops were identified. These subjects had a lower percentage of predicted FVC, FEV(1), and maximum expiratory and inspiratory pressures compared to the others, and a greater proportion had neurologically complete cervical injury (42% compared to 16%). In 19 subjects (40%), some expiratory efforts were not sustained maximally for > or = 6 s but had at least a 0.5-s plateau at residual volume (short efforts). In eight subjects (17%), some efforts were not short but had EBEV. In the remaining 21 subjects (44%), some efforts were short, some had EBEV, and some had both. If these efforts were not rejected, 262 of 278 subjects (94%) would have produced three acceptable efforts, and in 257 subjects (92%), the efforts were reproducible.

CONCLUSIONS

Subjects with SCI with the most impaired respiratory muscles and abnormal pulmonary function are able to perform spirometry reproducibly despite not meeting usual ATS acceptability standards. Exclusion of these subjects would lead to bias in studies of respiratory function in SCI. The modification of spirometry testing standards to include efforts with EBEV and with a 0.5-s plateau if < 6 s would reduce the potential for bias.

Heat shock protein 90 mediates the balance of nitric oxide and superoxide anion from endothelial nitric-oxide synthase

The balance of nitric oxide (.NO) and superoxide anion (O(2)) plays an important role in vascular biology. The association of heat shock protein 90 (Hsp90) with endothelial nitric-oxide synthase (eNOS) is a critical step in the mechanisms by which eNOS generates.NO. As eNOS is capable of generating both.NO and O(2), we hypothesized that Hsp90 might also mediate eNOS-dependent O(2) production. To test this hypothesis, bovine coronary endothelial cells (BCEC) were pretreated with geldanamycin (GA, 10 microg/ml; 17.8 microm) and then stimulated with the calcium ionophore, (5 microm). GA significantly decreased -stimulated eNOS-dependent nitrite production (p < 0.001, n = 4) and significantly increased -stimulated eNOS-dependent O(2) production (p < 0.001, n = 8). increased phospho-eNOS(Ser-1179) levels by >1.6-fold over vehicle (V)-treated levels. Pretreatment with GA by itself or with increased phospho-eNOS levels. In unstimulated V-treated BCEC cultures low amounts of Hsp90 were found to associate with eNOS. Pretreatment with GA and/or increased the association of Hsp90 with eNOS. These data show that Hsp90 is essential for eNOS-dependent.NO production and that inhibition of ATP-dependent conformational changes in Hsp90 uncouples eNOS activity and increases eNOS-dependent O(2) production.

Diabetes and hyperglycemia impair activation of mitochondrial K(ATP) channels

Hyperglycemia is an important predictor of cardiovascular mortality in patients with diabetes. We investigated the hypothesis that diabetes or acute hyperglycemia attenuates the reduction of myocardial infarct size produced by activation of mitochondrial ATP-regulated potassium (K(ATP)) channels. Acutely instrumented barbiturate-anesthetized dogs were subjected to a 60-min period of coronary artery occlusion and 3 h of reperfusion. Myocardial infarct size (triphenyltetrazolium chloride staining) was 25 +/- 1, 28 +/- 3, and 25 +/- 1% of the area at risk (AAR) for infarction in control, diabetic (3 wk after streptozotocin-alloxan), and hyperglycemic (15% intravenous dextrose) dogs, respectively. Diazoxide (2.5 mg/kg iv) significantly decreased infarct size (10 +/- 1% of AAR, P < 0.05) but did not produce protection in the presence of diabetes (28 +/- 5%) or moderate hyperglycemia (blood glucose 310 +/- 10 mg/dl; 23 +/- 2%). The dose of diazoxide and the degree of hyperglycemia were interactive. Profound (blood glucose 574 +/- 23 mg/dl) but not moderate hyperglycemia blocked the effects of high-dose (5.0 mg/kg) diazoxide [26 +/- 3, 15 +/- 3 (P < 0.05), and 11 +/- 2% (P < 0.05), respectively]. There were no differences in systemic hemodynamics, AAR, or coronary collateral blood flow (by radioactive microspheres) between groups. The results indicate that diabetes or hyperglycemia impairs activation of mitochondrial K(ATP) channels.

Ethanol enhances the functional recovery of stunned myocardium independent of K(ATP) channels in dogs

Chronic, intermittent exposure to small amounts of ethanol reduces myocardial infarct size in vivo. We tested the hypothesis that acute administration of ethanol enhances the functional recovery of stunned myocardium and that adenosine triphosphate-dependent potassium (K(ATP)) channels mediate this beneficial effect. Barbiturate-anesthetized dogs were instrumented for measurement of aortic and left ventricular pressure, +dP/dt(max), and subendocardial segment shortening (%SS) and were subjected to five 5-min periods of coronary artery occlusion, each separated by 5 min of reperfusion followed by a 3-h final reperfusion. In four groups (n = 7 each), dogs received 0.9% saline or ethanol (0.25, 0.5, or 1.0 g/kg over 30 min) in a random manner before occlusions and reperfusions. In other groups (n = 7 each), dogs received the K(ATP) channel antagonist glyburide (0.3 mg/kg, IV) 30 min before saline or ethanol (0.25 g/kg) was administered. Dogs receiving saline or glyburide alone demonstrated poor recovery of contractile function during reperfusion (%SS = 0.9% +/- 2.0% and 1.6% +/- 1.2% at 3 h, respectively). Recovery of %SS was enhanced in dogs receiving the 0.25- and 0.5-g/kg doses of ethanol (10.0% +/- 1.8% and 8.6% +/- 2.2% at 3 h, respectively) independent of alterations in hemodynamics or coronary collateral blood flow (radioactive microspheres). Glyburide did not affect improvement of recovery of stunned myocardium produced by ethanol (11.8% +/- 2.2% at 3 h). The results indicate that ethanol enhances the functional recovery of stunned myocardium independent of K(ATP) channels in vivo.

K(ATP) channels mediate the beneficial effects of chronic ethanol ingestion

Chronic ingestion of low doses of ethanol protects the myocardium from ischemic injury by activating adenosine receptors and protein kinase C. We tested the hypothesis that ATP-dependent potassium (K(ATP)) channels mediate these beneficial effects. Dogs were fed with ethanol (1.5 g/kg) or water mixed with dry food twice per day for 12 wk. After they were acutely instrumented for measurement of hemodynamics, dogs received saline (vehicle) or glyburide (0.1 mg/kg iv) and were subjected to 60 min of coronary artery occlusion followed by 3 h of reperfusion. Infarct size (through triphenyltetrazolium chloride staining) was significantly (P < 0.05) reduced to 14 +/- 1% of the left ventricular area at risk in ethanol-pretreated dogs compared with controls (25 +/- 2%). Glyburide alone did not affect infarct size (25 +/- 3%) but abolished the protective effects of ethanol pretreatment (28 +/- 3%). No differences in hemodynamics or coronary collateral blood flow (through radioactive microspheres) were observed among groups. The results indicate that K(ATP) channels mediate the protective effects of chronic consumption of ethanol.

Sarcolemmal and mitochondrial adenosine triphosphate- dependent potassium channels: mechanism of desflurane-induced cardioprotection

BACKGROUND

Volatile anesthetic-induced preconditioning is mediated by adenosine triphosphate-dependent potassium (KATP) channels; however, the subcellular location of these channels is unknown. The authors tested the hypothesis that desflurane reduces experimental myocardial infarct size by activation of specific sarcolemmal and mitochondrial KATP channels.

METHODS

Barbiturate-anesthetized dogs (n = 88) were acutely instrumented for measurement of aortic and left ventricular pressures. All dogs were subjected to a 60-min left anterior descending coronary artery occlusion followed by 3-h reperfusion. In four separate groups, dogs received vehicle (0.9% saline) or the nonselective KATP channel antagonist glyburide (0.1 mg/kg intravenously) in the presence or absence of 1 minimum alveolar concentration desflurane. In four additional groups, dogs received 45-min intracoronary infusions of the selective sarcolemmal (HMR 1098; 1 microg. kg-1. min-1) or mitochondrial (5-hydroxydecanoate [5-HD]; 150 microg. kg-1. min-1) KATP channel antagonists in the presence or absence of desflurane. Myocardial perfusion and infarct size were measured with radioactive microspheres and triphenyltetrazolium staining, respectively.

RESULTS

Desflurane significantly (P < 0.05) decreased infarct size to 10 +/- 2% (mean +/- SEM) of the area at risk as compared with control experiments (25 +/- 3% of area at risk). This beneficial effect of desflurane was abolished by glyburide (25 +/- 2% of area at risk). Glyburide (24 +/- 2%), HMR 1098 (21 +/- 4%), and 5-HD (24 +/- 2% of area at risk) alone had no effects on myocardial infarct size. HMR 1098 and 5-HD abolished the protective effects of desflurane (19 +/- 3% and 22 +/- 2% of area at risk, respectively).

CONCLUSION

Desflurane reduces myocardial infarct size in vivo, and the results further suggest that both sarcolemmal and mitochondrial KATP channels could be involved.

Isoflurane preconditions myocardium against infarction via activation of inhibitory guanine nucleotide binding proteins

BACKGROUND

Isoflurane-induced myocardial protection during ischemia is mediated by adenosine triphosphate-regulated potassium (KATP) channels; however, the intracellular signal transduction cascade responsible for this process has been incompletely evaluated. The authors tested the hypothesis that isoflurane reduces myocardial infarct size through a Gi protein-mediated process.

METHODS

Forty-eight hours after pretreatment with vehicle (0.9% saline) or the Gi protein inhibitor pertussis toxin (10 microg/kg intravenously), barbiturate-anesthetized dogs (n = 43) were instrumented for measurement of aortic and left ventricular pressures and maximum rate of increase of left ventricular pressure. All dogs were subjected to a 60-min left anterior descending coronary artery occlusion followed by 3-h reperfusion. In four separate groups, vehicle- or pertussis toxin-pretreated dogs were studied with or without administration of 1 minimum alveolar concentration isoflurane. In two additional groups, dogs received the direct KATP channel agonist nicorandil (100 microg/kg bolus and 10 microg x kg-1 x min-1 intravenous infusion) in the presence or absence of pertussis toxin pretreatment. Myocardial perfusion and infarct size were measured with radioactive microspheres and triphenyltetrazolium staining, respectively.

RESULTS

Isoflurane significantly (P < 0.05) decreased infarct size to 7 +/- 2% of the area at risk compared with control experiments (26 +/- 2%). Pertussis toxin pretreatment alone had no effects on myocardial infarct size (31 +/- 4%) but blocked the beneficial effects of isoflurane (21 +/- 3%). Nicorandil decreased infarct size (11 +/- 2%), but, in contrast to isoflurane, this effect was independent of pertussis toxin pretreatment (11 +/- 1%).

CONCLUSION

Isoflurane reduces myocardial infarct size by a Gi protein-mediated mechanism in vivo.

Diabetes abolishes ischemic preconditioning: role of glucose, insulin, and osmolality

Recent evidence indicates that hyperglycemia is an important risk factor for the development of cardiovascular disease. We tested the hypothesis that myocardial infarct size is related to blood glucose concentration in the presence or absence of ischemic preconditioning (PC) stimuli in canine models of diabetes mellitus and acute hyperglycemia. Barbiturate-anesthetized dogs were subjected to a 60-min period of coronary artery occlusion and 3-h reperfusion. Infarct size was 24 +/- 2% of the area at risk (AAR) for infarction in control dogs. PC significantly (P < 0.05) decreased the extent of infarction in normal (8 +/- 2% of AAR), but not diabetic (22 +/- 4% of AAR), dogs. Infarct size was linearly related to blood glucose concentration during acute hyperglycemia (r = 0.96; P < 0.001) and during diabetes (r = 0.74; P < 0.002) in the presence or absence of PC stimuli. Increases in serum osmolality caused by administration of raffinose (300 g) did not increase infarct size (11 +/- 3% of AAR) or interfere with the ability of PC to protect against infarction (2 +/- 1% of AAR). The results indicate that hyperglycemia is a major determinant of the extent of myocardial infarction in the dog.

Regional hyperthermia for deep-seated malignancies using the BSD annular array

Forty-four patients were treated using the BSD-1000 Annular Phased Array between April 1983 and December 1986. There were 32 pelvic, nine abdominal, two extremity, and one thoracic sites treated. Mean tumour volume was 646 cc. Thirty-nine patients had concurrent radiation therapy, receiving a mean dose of 38 Gy. Mean average temperature was 41.0 +/- 1.4 degrees C. Most patients experienced local or systemic toxicity, requiring temporary treatment interruption in 33 patients, and termination of treatment in eight. Chronic complications were seen in four, but these were in patients receiving high total radiation doses as well. There were six complete and five partial responses. Among the 32 patients with pelvic tumours, mean tumour volume was 317 cc, mean radiation dose was 42 Gy, and mean average temperature was 41.3 +/- 1.2 degrees C. There were five complete and four partial responses. Achieving tumour temperatures greater than or equal to 42 degrees C with the annular array is difficult, due to both systemic and local toxicity. To improve clinical hyperthermia for thoracic, abdominal, and pelvic tumours, new technologies such as steerable phased array microwave systems; scanned, focused ultrasound; and permanently implantable thermoregulating ferromagnetic seeds, or new approaches such as using drugs to alter blood flow, or combining hyperthermia with antineoplastic drugs or biological agents, will be necessary.

Effects of dihydrocodeine, alcohol, and caffeine on breathlessness and exercise tolerance in patients with chronic obstructive lung disease and normal blood gases

We measured breathlessness and exercise tolerance in 12 patients with chronic airways obstruction, moderate or severe breathlessness, and low or normal arterial carbon dioxide tension, after the patients received dihydrocodeine, alcohol, caffeine, or placebo (through double-blind administration). Forty-five minutes after ingestion, dihydrocodeine had reduced breathlessness by 20 per cent and increased exercise tolerance by 18 per cent, with a reduction in ventilation and oxygen consumption at submaximal work loads but with no change in spirometric volumes. Oxygen also reduced breathlessness and provided additional benefit to that achieved with dihydrocodeine (at three hours after ingestion) when the two were given together: the reduction of breathlessness was 18 per cent with dihydrocodeine; 22 per cent with oxygen; and 32 per cent with dihydrocodeine plus oxygen. Alcohol increased forced vital capacity by 9 per cent, and exercise tolerance by 7 per cent. Caffeine had no deleterious effect on breathlessness or exercise tolerance, despite increasing ventilation during rest and exercise. We conclude that opiates may be valuable for the treatment of breathlessness in selected patients; further evaluation is needed, particularly of the long-term benefits and safety.

Drug treatment of breathlessness: contrasting effects of diazepam and promethazine in pink puffers

Fifteen out of 18 "pink and puffing" patients completed a double-blind, placebo-controlled cross-over trial of diazepam and promethazine for breathlessness and reduced exercise tolerance. Dosages were 25 mg and 125 mg daily, respectively, and each course lasted two weeks. Patients with psychiatric or other major medical histories were excluded. Of the three patients who did not complete the trial, one died during an exacerbation of breathlessness while taking diazepam, one was withdrawn because of mild hypercapnia while taking placebo, and one suffered intolerable drowsiness while taking diazepam. Of the remaining 15 patients, six needed a reduction in dosage because of drowsiness: one of these was taking promethazine and five diazepam. Diazepam had no effect on breathlessness and noticeably reduced exercise tolerance. Promethazine reduced breathlessness and improved exercise tolerance without altering lung function. From these results diazepam is contraindicated for breathlessness and reduced exercise tolerance in fixed airways obstruction, but promethazine may be beneficial.

Oxygen relieves breathlessness in "pink puffers"

The effect of oxygen on breathlessness and exercise tolerance was examined in "pink and puffing" patients with fixed airways obstruction. When breathing oxygen, patients were less breathless and walked further. This was true whether the cylinder was carried by the patient or by an assistant. It was not possible to identify those patients who would benefit most. The best method of assessing improvement was by comparing breathlessness on a standardised progressive exercise test on a treadmill. Four patients had a greater than 30% reduction in breathlessness on submaximum exercise when breathing oxygen. Breathing oxygen for five or fifteen minutes before exercise but not during exercise (predose) resulted in a similar improvement in exercise tolerance. For short periods of exercise predosing with oxygen provides a convenient alternative to continuous oxygen. For longer periods of exercise the benefits of portable oxygen in selected patients have been previously underestimated.