Neoadjuvant PFL augmented by methotrexate and piritrexim followed by concomitant chemoradiotherapy for advanced head and neck cancer: a feasible and active approach

To increase the complete remission (CR) rate achieved with two cycles of cisplatin, continuous infusion fluorouracil (5-FU) and oral leucovorin (PFL) we added two antifolate drugs, methotrexate (MTX) and the lipophilic piritrexim (PTX), to the combination (PFL-MP). Twenty-eight patients with previously untreated Stage IV squamous cell carcinoma of the head and neck received 2 cycles of cisplatin 100 mg/m2 on day 1 followed by a 5-day continuous infusion of 5-FU at 800 mg/m2/day and 100 mg of leucovorin administered orally every 4 hours. MTX was administered at 40 mg/m2 IV on day 15 and PTX at 75 mg orally twice daily on days 22 to 26, with cycle 2 starting on day 36. After 2 of the first 5 patients had tumor progression between days 15 and 35, the regimen was intensified to MTX 50 mg/m2, PTX 100 mg twice daily and a cycle duration of 28 days. Local therapy consisted of surgery and/or radiotherapy with concomitant 5-FU and hydroxyurea (FHX) administered every other week. Eleven patients (39%, 95% confidence intervals 21-57%) had a CR, 9 (32%) had a PR, and four patients had no response. Four patients were unevaluable for response to PFL-MP. Patients with poor performance status or N3 disease were less likely to achieve a CR. Mucositis following PFL was the dose-limiting toxicity. Local therapy included surgery in 15 patients and FHX chemoradiotherapy in 19 patients. The administration of FHX in this setting proved feasible and the regimen was given near the intended dose intensity in the majority of patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Postoperative hypoxaemia after major abdominal vascular surgery

We have studied the severity and duration of nocturnal hypoxaemia before operation and for the first five nights after operation after elective major abdominal vascular surgery. Oxygen supplementation was almost 100% effective in keeping oxygen saturation greater than 90% during the early postoperative period; however, 50% of patients spent prolonged periods with an SpO2 less than 85% during at least one night after operation. The risk of severe hypoxaemia persists well beyond the current prescription of supplementary oxygen in these high risk patients. A significant association exists between the mean preoperative overnight saturation value and the nocturnal saturation observed subsequently in the later postoperative period.

Postoperative myocardial ischaemia: temporal association with nocturnal hypoxaemia

Three patients presenting for elective aortic surgery were studied before operation and for up to 3 days after operation with ambulatory electrocardiographic monitoring and nocturnal pulse oximetry. Supplementary oxygen was administered for the first 2 days after operation and withdrawn on the 3rd morning after operation. Heart rate remained increased for the first 3 days after operation. Two patients developed episodes of myocardial ischaemia during the first 48 h after operation while their arterial oxygen saturation remained greater than 90%. On the third day, and during the third night after operation, both the severity and duration of myocardial ischaemia increased markedly, associated with arterial hypoxaemia. A temporal relationship between decreases in oxygen saturation and fluctuations in ST segment level were observed in the three patients.

Postoperative obstructive sleep apnoea. Haemodynamic effects of treatment with nasal CPAP

A 74-year-old man presenting for aortic reconstructive surgery showed severe, previously undiagnosed obstructive sleep apnoea during overnight oximetry monitoring before operation. Postoperatively, in the first 4 hours following extubation, he suffered 238 episodes of respiratory obstruction. These events were associated with frequent arousals, large fluctuations in systolic and diastolic blood pressure. Administration of nasal continuous positive airways pressure abolished the obstructions and allowed an uninterrupted night's sleep, with a significantly reduced blood pressure. Subsequent dips in oxygen saturation as a result of respiratory obstruction recurred on the fifth postoperative night. We conclude that pre-operative overnight oximetry may be useful in identifying those patients at risk of postoperative upper airway obstruction. Use of nasal continuous positive airway pressure may prevent the occurrence of early postoperative obstruction and the associated haemodynamic changes.

Haemodynamic effects of periodic ventilation: abolition with supplementary oxygen

A 63-yr-old man was noted to breathe with a periodic pattern of ventilation during sleep, both before and after operation for coronary artery grafting, and 6 weeks later after aortic aneurysm repair. Periodic ventilation was associated with cyclic oxygen desaturations and increases in heart rate and arterial pressure. Administration of oxygen was found to abolish consistently the periodic pattern and the associated haemodynamic changes.

The incidence and value of rectal examination in children with suspected appendicitis

Rectal examination is considered an important part of the examination of patients presenting with abdominal pain. However, children find anal digitation unpleasant and it was our impression that doctors were becoming less insistent on performing a rectal examination. We performed an audit of rectal examination and assessed whether this made any difference to the management of children with acute abdominal pain. We looked at the records of 48 children from 1989 and 49 children from 1985 presenting with abdominal pain. We found that the rate of rectal examination was halved in this time. Diagnostic accuracy was similar in the two groups, and the morbidity rate was the same. These findings call into question the need for routine rectal examination in children with suspected appendicitis.

A randomized study comparing two regimens of neoadjuvant and adjuvant chemotherapy in multimodal therapy for locally advanced head and neck cancer

Two regimens of neoadjuvant chemotherapy for previously untreated patients with locally advanced head and neck cancer were compared with the goal of identifying a regimen with a greater than 50% complete response (CR) rate. Patients with a performance status of 0 to 2 and normal end-organ function were randomized to receive either four cycles of neoadjuvant methotrexate, cisplatin, and continuous infusion 5-fluorouracil (5-FU) (MPF) (arm A), or four cycles of bleomycin, cisplatin, and methotrexate (PBM) alternating with cisplatin and 5-FU (PF) (arm B). Patients with a performance status of greater than 2 or a carbon monoxide diffusion capacity of less than 50% of the predicted value were assigned to the arm A regimen but were analyzed separately (arm C). Local therapy consisted of surgery (for patients with resectable disease) or radiation therapy followed by two cycles of adjuvant chemotherapy with the regimen that was administered initially. Of the 42 patients who were evaluated, 16 were randomized to arm A, 13 to arm B, and 13 to arm C. The clinical CR rate was 19% on arm A (95% confidence interval, 0% to 38%), 39% on arm B (95% confidence interval, 12% to 66%) (P = 0.41), and 54% on arm C (95% confidence interval, 27% to 81%). At a median follow-up time of 35 months, the 2-year actuarial survival rate was 61% on arm A, 69% on arm B (the P value was not significant), and 38% on arm C. The 2-year survival rate for all 42 patients who were treated was 57% and the median survival time was 31 months. Toxicities of neoadjuvant chemotherapy on all arms consisted of mild to moderate myelosuppression and renal toxicity. The incidence of moderate to severe mucositis was significantly higher on arm A than arm B (P = 0.02). Two cycles of adjuvant chemotherapy were administered to only 11 of 42 patients due to patient refusal or cumulative toxicity. In conclusion, both neoadjuvant chemotherapy regimens resulted in similar response and survival rates, but mucositis was more severe with arm A. However, since neither regimen was likely to cause a CR rate of greater than 50%, this study was closed to further patient accrual.

Is there central respiratory depression after intravenous administration of propranolol?

Beta-adrenergic blockers have been reported to depress central ventilatory drive. The authors investigated this possibility in a double-blind, randomized fashion in 12 healthy volunteers who received 0.1 mg.kg-1 of propranolol and normal saline intravenously at two separate study sessions. A modified Read rebreathing technique was used. Both ventilatory and occlusion pressure responses to CO2 were measured to help separate peripheral (airway) from central mechanisms. Significant beta blockade was demonstrated by statistically lower heart rate responses to CO2 rebreathing after propranolol, but not normal saline. Nevertheless, propranolol exerted no significant effect on resting end-tidal CO2 or the ventilatory and occlusion pressure responses to CO2. Although health subjects appear to have minimal alterations in their ventilatory response to CO2 after beta-adrenergic blockade, patients with airway disease may still experience significant changes in ventilation. In addition, drug interaction studies may give further insight into the presence or absence of any respiratory effects of propranolol.

Hydroxyurea, fluorouracil, and concomitant radiotherapy in poor-prognosis head and neck cancer: a phase I-II study

Hydroxyurea and fluorouracil (5-FU) are active cytotoxic drugs in head and neck cancer and have shown synergistic activity in vitro. Both drugs also act as radiosensitizers. Therefore, we administered radiotherapy at daily fractions of 180 to 200 cGy with simultaneous continuous infusion 5-FU at 800 mg/m2/d and escalating daily doses of hydroxyurea for five days. Cycles were repeated every other week until completion of radiotherapy. Thirty-nine inoperable patients were treated at six dose levels of hydroxyurea ranging from 500 mg to 3,000 mg orally daily. Little effect of hydroxyurea on the WBC or platelet count was noted in patients receiving less than 2,000 mg daily, whereas both parameters decreased progressively in patients receiving 2,000 mg daily or more. Mucositis occurred at all dose levels, requiring frequent dose reduction of 5-FU; however, in patients receiving a daily hydroxyurea dose of 2,000 mg or less, the median weekly 5-FU dose administered was 1,725 mg/m2 (86% of the intended 5-FU dose), whereas at daily hydroxyurea doses exceeding 2,000 mg, the median weekly 5-FU dose decreased to 1,133 mg/m2 (57%) (P = .001). Of 15 evaluable patients with recurrent disease after prior local therapy only one failed to respond; six had a complete response (CR), and eight a partial response (PR). Of 17 evaluable patients without prior local therapy, 12 had a CR, with no patient developing recurrence in the irradiated field to date; five patients had a PR. We conclude that the recommended dose of hydroxyurea in this regimen is 2,000 mg daily. That dose will cause mild to moderate myelosuppression and will allow for delivery of greater than 80% of the intended 5-FU dose. The activity of this regimen in poor-prognosis head and neck cancer exceeds 90%; its further investigation in previously untreated patients is warranted.

Dissociation between diaphragmatic and rib cage muscle fatigue

To assess rib cage muscle fatigue and its relationship to diaphragmatic fatigue, we recorded the electromyogram (EMG) of the parasternal intercostals (PS), sternocleidomastoid (SM), and platysma with fine wire electrodes and the EMG of the diaphragm (DI) with an esophageal electrode. Six normal subjects were studied during inspiratory resistive breathing. Two different breathing patterns were imposed: mainly diaphragmatic or mainly rib cage breathing. The development of fatigue was assessed by analysis of the high-to-low (H/L) ratio of the EMG. To determine the appropriate frequency bands for the PS and SM, we established their EMG power spectrum by Fourier analysis. The mean and SD for the centroid frequency was 312 +/- 16 Hz for PS and 244 +/- 48 Hz for SM. When breathing with the diaphragmatic patterns, all subjects showed a fall in H/L of the DI and none had a fall in H/L of the PS or SM. During rib cage emphasis, four out of five subjects showed a fall in H/L of the PS and five out of six showed a fall in H/L of the SM. Four subjects showed no fall in H/L of the DI; the other two subjects were unable to inhibit diaphragm activity to a substantial degree and did show a fall in H/L of the DI. Activity of the platysma was minimal or absent during diaphragmatic emphasis but was usually strong during rib cage breathing. We conclude that fatigue of either the diaphragm or the parasternal and sternocleidomastoid can occur independently according to the recruitment pattern of inspiratory muscles.(ABSTRACT TRUNCATED AT 250 WORDS)

Perioperative complications of in-situ vein bypass

Experience with 146 in-situ vein bypass procedures for obliterative arterial disease are reviewed to determine the specific complication of the technique. Vein wall injury with the Hall valvulotome occurred in 6 patients (4%) and vein patching of a stenosed femoral vein was required in 2 patients. Residual arteriovenous fistulae occurred in 24 patients (16.5%) of whom 9 had an associated graft thrombosis distal to the fistula of which 6 were corrected by thrombectomy and fistula ligation. Perioperative thrombosis occurred in 29 grafts (20%) and was more common in the femoropopliteal group (23/80) than in the femorocrural group (6/66) (P less than 0.01, X2 = 7.55). Fourteen of the femoropopliteal and two of the femorocrural thromboses were corrected resulting in an immediate patency of 89% and 94% respectively with the cumulative patency at one year being 77.5% and 79%. Complications of the in-situ bypass technique remain despite having largely overcome the problems of valve disruption. However, until a standard method emerges careful note must be made of technique and complications when considering reports of in-situ bypass patency.

Helium-oxygen breathing in severe chronic obstructive pulmonary disease

The effect of breathing helium-oxygen (He-O2) mixtures was evaluated in 15 patients with severe chronic obstructive pulmonary disease (COPD). Gas exchange was assessed during quiet breathing at rest before and after 15 minutes of breathing 80 percent He-20 percent O2 mixtures in all patients. Functional residual capacity (FRC) determined during argon (Ar) washing studies fell significantly while breathing He-O2, but we did not find significant changes in minute ventilation, tidal volume, respiratory frequency, or inspiratory or expiratory timing. Eleven patients showed decreases in arterial PCO2 and CO2 excretion during resting breathing on He-O2. Expiratory flows were increased at a given lung volume during He-O2 breathing as expected. Apparently, mechanical work of breathing was decreased in patients with severe COPD while breathing He-O2, leading to a reduction in VCO2 and improvement in overall alveolar ventilation. These findings lend support to the therapeutic use of He-O2 under some conditions in patients with severe COPD.

Differential costal and crural diaphragm compensation for posture changes

The electromyographic (EMG) activities of the costal and crural diaphragm were recorded from bipolar fine-wire electrodes placed in the costal fibers adjacent to the central tendon and in the anterior portions of the crural fibers in 12 anesthetized cats. The EMG activities of costal and crural recordings were compared during posture changes from supine to head up and during progressive hyperoxic hypercapnia in both positions. The activity of both portions of the diaphragm was greater in the head up compared with supine posture at all levels of CO2; and increases in crural activity were greater than those in costal activity both as a result of changes in posture and with increasing CO2 stimuli. These results are consistent with the concept that diaphragm activation is modulated in response to changes in resting muscle length, and further, that neural control mechanisms allow separate regulation of costal and crural diaphragm activation.

Costal and crural diaphragm and intercostal muscle activity during augmented breaths in cats

The pattern of electrical activity of the costal and crural diaphragm and the external intercostal muscles was ascertained in ten anesthetized spontaneously breathing cats during eupnea and during augmented breaths. All muscles studied manifested a biphasic activity pattern during augmented breaths. The increase in activity during the latter portion (phase II) of the augmented breaths was greater for the crural than the costal diaphragm (P less than 0.05), and greater for cranially located intercostal muscles than for the costal diaphragm (P less than 0.02) and more caudally located intercostal muscles (P less than 0.02). These results suggest that during augmented breaths, activity of different thoracic muscles is modulated in a non-uniform manner.

The respiratory activity of human levator costae muscles and its modification by posture

The activation of the levator costae, a set of axial muscles inserted between each rib and the vertebra immediately rostral, has been studied electromyographically in a human subject, standing upright, with head erect ('neutral' posture). Caudal levator costae muscles (T9, and T10) are active during eupnoea. Periodic activity in phase with inspiration occurs in admixture with different levels of tonic activity that is strongly influenced by posture. Postural changes and various voluntary respiratory manoeuvres which should lengthen or shorten the levator costae muscles increase and decrease, respectively, their activity in the 'neutral' posture. The tonic activity was most readily enhanced by contralateral flexion of the spine, and this could bring to threshold phasic activity not otherwise present. Conversely, ipsilateral flexion could abolish both phasic and tonic components. Active expiratory efforts and static voluntary relaxation of the respiratory muscles could diminish or abolish levator costae activity. Paradoxically, chest-directed inspiratory efforts maintained at elevated lung volume with open glottis could also diminish or abolish levator costae activity. We attribute this to shortening of the levator costae muscles and unloading of their muscle spindles by the elevation of the ribs due to the action of the external intercostal and parasternal muscles. The results are discussed in relation to the mechanical coupling between the diaphragm and the lower rib cage; emphasis is given to the possible independent motions of the lower two or three ribs and the abductor action of their corresponding levator costae muscles, based on anatomico-physiological considerations.

Aspirin and dipyridamole reduce platelet deposition on prosthetic femoro-popliteal grafts in man

Platelet inhibitory drugs may be used in an attempt to reduce high failure rates in small artery bypass using prosthetic grafts. We evaluated in patients the effects of aspirin and dipyridamole (ASA/DPM) on radiolabelled platelet accumulation on femoro-popliteal grafts of Dacron, polytetrafluorethylene and saphenous vein. Forty-seven patients awaiting femoro-popliteal bypass received, at random and double blind, either ASA/DPM or placebo capsules. On the seventh postoperative day, the 42 remaining patients with patent grafts were injected with autologous 111-Indium labelled platelets. Graft platelet accumulation was expressed as the Thrombogenicity Index (TI), which was defined as the mean daily rise in the ratio of radioactivity over the graft to that over the contralateral thigh. ASA/DPM reduced mean (+/- s.e. mean) TI in Dacron grafts from 0.25 +/- 0.09 on placebo to 0.16 +/- 0.05 (p less than 0.05). Mean TI in polytetrafluorethylene grafts was also significantly lower at 0.06 +/- 0.01 on ASA/DPM compared to 0.16 +/- 0.03 on placebo. Vein grafts, however, accumulated few, if any, labelled platelets and ASA/DPM had no further influence. ASA/DPM reduces platelet accumulation in prosthetic femoro-popliteal grafts in man.

Parameter estimation in linear functional relationships

We present the application of a weighted least-squares technique to extract parameter estimates in linear models when all variables are subject to error and the goal of the investigation is the value of the parameters themselves. We assume that the relative variances of the variables are known and that the errors between variables are independent. The method of parameter estimation for linear functional relationships is presented, and we describe its differences from linear regression. We discuss how to obtain confidence intervals for the parameter estimates with an emphasis on computer Monte Carlo simulations. An explicit example related to measurements of lung volume changes is presented. An eigenvalue analysis of the data pertaining to the number of independent variables and a physical interpretation of the data space are also discussed.

High-frequency oscillations in human respiratory electromyograms during voluntary breathing

Electromyograms (EMGs) from respiratory muscles were obtained from human subjects during voluntarily controlled breathing. In 10 studies on 6 subjects EMGs were recorded from the right and left lower ventrolateral surface of the rib cage while the subject emphasized the use of his diaphragm for breathing. Simultaneous samples of the 2 EMG signals of 256-ms duration were obtained once per inspiration (in either the first of second half of inspiration) from each of 30 consecutive breaths using a laboratory minicomputer. Individual power spectra for the 2 EMG signals, and the squared coherence spectrum between them, were calculated. From the coherence spectrum common high-frequency oscillations could be identified within two frequency ranges: 70-100 Hz and 20-50 Hz. Peaks at similar frequencies were identified in both early-inspiratory and late-inspiratory EMG signals. Similar experiments were done on 3 subjects from whom an esophageal diaphragm EMG was obtained as well. The coherence spectrum between the esophageal EMG and the right rib cage surface EMG again demonstrated the presence of common high-frequency oscillations in the same frequency ranges as above. Evidence of these oscillations was not usually apparent in the power spectra. When ECG signal components were allowed to contaminate some of the EMG data samples, the coherence spectrum could be altered considerably, leading to inappropriate conclusions regarding the presence or absence of high-frequency oscillations. It is hypothesized that these high-frequency oscillations are similar to those described in nerve recordings from previous studies on anesthetized and decerebrate cats and dogs and a mechanism for their expression in EMG signals is proposed. The coherence spectrum is a very sensitive method for detecting related signal components in two signals. That high-frequency oscillations can be detected using the less sensitive techniques of autocorrelation and power spectral analysis in some animal preparations may reflect an enhancement of these oscillations in those preparations.

Postural changes in rib cage and abdominal volume-motion coefficients and their effect on the calibration of a respiratory inductance plethysmograph

Volume-motion coefficients were determined for the rib cage and abdomen in normal human subjects in upright, supine, and semirecumbent postures by the isovolume calibration technique of Konno and Mead (J Appl Physiol 1967; 22:407-422, using the respiratory inductive plethysmograph (RIP) to measure displacements of rib cage and abdominal walls. Volume motion coefficients changed systematically with posture; those for the rib cage were smallest in the upright posture, and for the abdomen, greatest in the upright posture. These volume motion coefficients were then used to estimate tidal volume during resting breathing in the different postures, and compared with estimates of tidal volume derived from calibration by the change in posture technique reported by Sackner and coworkers (American Review of Respiratory Disease 1980; 122:867-871). Estimates of tidal volume derived from RIP signals using both calibration techniques were compared with independently measured spirometric volume changes. Errors in tidal volume averaged 6% with the isovolume technique and 9 to 23% with the change in posture technique (depending upon whether the calibrating postures were upright, supine or semirecumbent supine). The larger errors with the change in posture calibration method are attributable to both the change in volume motion coefficients with posture and the change in distribution of tidal volume between rib cage and abdomen compartments with change in posture.

Sleep apnea considered as a control system instability

In the present study a mathematical model of the chemical control of respiration is described which attempts to simulate periodic breathing during sleep. The model is an extension of an earlier model which has been shown to successfully reproduce the transient effects of CO2 inhalation on breathing, controlled changes in ventilation on arterial gas tension, and Cheyne-Stokes breathing. Included in the extended model are the effects of chemical stimuli during sleep on both chest wall and upper airway muscle activity. Data is presented indicating that simulations from the model reproduce reasonably well the essential features of the results obtained in eight subjects with periodic respiration during sleep when breathing room air, O2, or low concentrations of CO2. Simulations from the model and the experimental data suggest that periodic breathing during sleep results from unstable operation in the respiratory control system analogous to that seen during instabilities in physical control systems. The model indicates that obstructive as well as central apneas can be produced by control system instability. Furthermore, central apneas increase the likelihood of obstructive apneas while obstructive apneas tend to aggravate the control instability. The model results predict that the characteristics of the periodic breathing seen during sleep, such as apnea length, will depend on circulation time and the sensitivity of both upper airway and chest wall muscles to hypercapnia and hypoxia.

Effect of progressive hypoxia on breathing during sleep

We examined the effects of progressive hypoxia on breathing during wakefulness and quiet (NREM) sleep in 17 healthy young adults (11 males and 6 females). Ventilation was determined from quantitative measurements of abdominal and rib cage excursions using magnetometers or inductive plethysmography. Hypoxia was induced by blending N2 into the inspiratory line of a loose-fitting mask while O2 saturation was monitored with an ear oximeter. No attempt was made to maintain isocapnia. Ventilatory responses to hypoxia were depressed in 2 male subjects by sleep, but were unchanged or increased in the others. Thus on the average, sleep produced no change in ventilatory responses to hypoxia. There was no consistent difference in the frequencies or tidal volumes attained at a given level of ventilation during hypoxia awake and asleep. During sleep there was relatively more rib cage than abdominal movement. Relief of hypoxia was followed by periodic breathing during sleep in 12 subjects but in only 2 subjects when awake. In two thirds of the trials, hypoxia failed to produce arousal even though arterial O2 saturation was allowed to fall below 75%. The results suggest that (1) sleep potentiates apnea producing effects of O2 changes but has inconsistent effects on ventilatory responses to hypoxia, and (2) hypocapnic hypoxia is not an invariably potent stimulus for arousal.