膈肌功能测定及其在慢性阻塞性肺疾病中的应用

目的　比较最大跨膈压 (Pdimax)、最大口腔吸气压 (MIP)、最大吸鼻跨膈压 (Pdisniff)和颤搐性跨膈压(Pdi(t)ele)在评价膈肌功能中的差异及其在慢性阻塞性肺疾病 (COPD)中的应用。方法　对 13例正常者和 7例轻度与 7例重度COPD病人分别测定Pdimax、MIP、Pdisniff和Pdi(t)ele。结果　 (1)正常对照组的Pdimax、MIP、Pdisniff与轻度COPD组比较差异无显著性 ,与重度COPD组比较差异有显著性 (P 分别为 :<0 0 1、0 0 5和 0 0 5 ) ;而正常对照组Pdi(t)ele均比轻度和重度COPD组的高 (P均 <0 0 1)差异显著。 (2 )Pdi(t)ele的个体内变异性在正常对照组中均比Pdimax、MIP、Pdisniff小 (P分别为 :<0 0 1、0 0 1和 0 0 5 ) ;在COPD组中 ,明显比Pdimax小 (P <0 0 1) ,而与MIP和Pdisniff比较差异没有显著性。 (3)Pdi(t)ele与FEV1具有显著相关性 (P <0 0 5 )。结论　Pdi(t)ele能更客观、更敏感地反映膈肌功能。     

P波离散度对经皮球囊二尖瓣扩张术后心房纤颤发作的预测价值

目的 探讨P波离散度预测经皮球囊二尖瓣扩张术(PBMV)后心房纤颤发作的价值.方法 选择风湿性心脏病,二尖瓣狭窄并成功行PBMV术,术前为窦性心律者,共95例.所有患者均测量PBMV前12导联同步心电图P波宽度,计算最宽P波(Pmax)、最窄P波(Pmin)并取两者差的平均值,即为P波离散度(Pd),Pd=Pmax-Pmin.结果PBMV术后59例患者维持窦性心律(对照组),男8例,女51例,年龄24～57岁(36.8±8.3岁);36例患者出现心房纤颤(房颤组).男13例,女23例,年龄18～56岁(38.1±7.8岁).两组患者在年龄、心率、左室舒张期内径、右室舒张期内径和左室射血分数无统计学差异.房颤组左房内径(46.63±2.36mm)比对照组(43.51±2.51mm)显著增大(P<0.05).房颤组Pmax(121.67±14.64ms)、Pd(37.50±9.37ms)比对照组Pmax(106.38±12.24ms)、Pd(23.97±12.70ms)显著延长(P<0.01).以Pmax≥110ms预测心房纤颤的敏感性80.55%,特异性50.85%,准确性61.05%.以Pd≥40ms预测心房纤颤的敏感性69.44%,特异性32.20%,准确性68.42%.结论 Pd作为一项无创性心电学指标,对PBMV术后发作心房纤颤的预测有一定临床价值.     

西沙必利对上消化道腔内压的影响

用气囊法测压观察了60例正常人及30例十二指肠球部溃疡(DU)患者的上消化道压力指标,发现正常人食管下括约肌压力(LESP)为3.54±1.17kPa,胃内压(GP)为0.84±0.41kPa,食管体部静息压(EBP)为1.09±0.66kPa,食管上括约风压力(UESP)为8.26±2.90kPa,食管中上段及中下段传导速度分别为3.35±1.60cm/s和3.32±1.30cm/s,胃食管压力梯度(GEPG)为0.24±0.60kPa,屏障压(LESP-GP)为2.65±0.94kPa,LESE/GP为5.32±2.80.DU患者的LESP为2.47±0.90kPa,低于正常人(P<0.05),LESP-GP为1.73±0.99,亦低于正常人(P<0.01).其余压力指标与正常人比较均无明显差异(P>0.05).正常组及DU组服西沙必利后LESP、GP、中上段传导、中下段传导、UESP均升高(P<0.05),GEPG均降低(P<0.01).另外正常组的LESP/GP亦降低(P<0.05),其余压力指标与服药前无明显差异(P>0.05).     

癔球症的食管运动功能研究

目的 :探讨食管运动功能尤其是上食管括约肌 (UES)运动功能与癔球症的关系。方法 :采用PolygrafHRTM食管测压系统对2 2例癔球症患者进行食管运动功能测定 ,2 5例健康志愿者作为对照组。结果 :UES长度、静息压、松弛压、松弛率、食管体收缩压、下食管括约肌 (LES)长度及LES静息压 ,癔球症患者组 (3 .65± 0 .62cm ,43 .35± 7.96mmHg,0 .32± 0 .80mmHg ,1 0 0 % ,58.59± 1 5 .57mmHg,4.0 7± 0 .96cm ,2 6 .93± 3 .3mmHg)与正常对照组 (3 .52± 0 .71cm ,41 .83± 8.52mmHg,0 .35± 0 .89mmHg ,1 0 0 % ,56 .32± 1 3 .44mmHg,4.1 2± 0 .82cm ,2 8.56± 4 .5mmHg)比较均无显著差异 (P >0 .0 5)。结论 :大多数癔球症患者的食管运动功能是正常的 ,UES功能状况可能与癔球症的发生无关     

测尿氧压诊断尿路感染

作者测定30例尿培养阴性的正常人和20例尿路感染(UTI)患者尿内氧压(PUO_2)。结果显示,正常人 PUO_2为4.81±1.03kPa,而 UTI 患者 PUO_2为1.601±1.18kPa。如以(?)—2S为正常值下限,正常人28例(93%)PUO_2高于2.763kPa,2例(7%)低于上述值,UTI 患者中仅2例(10%)高于此值,18例(90%)2.763kPa 表明 PUO_2诊断 UTI 的阳性率为90%,假阳性、假阴性率分别7%、10%。     

后腹腔镜术中全麻诱导及气腹对食管下括约肌及胃食管跨障压的影响

目的 探讨后腹腔镜下泌尿外科手术中全麻诱导及CO2气腹对食管下括约肌压力及胃食管跨障压的影响.方法 选择于全身麻醉下行后腹腔镜泌尿外科手术患者（ASA Ⅰ～Ⅱ级）30例,采用双通道压力传感器连接生物信号采集处理系统测量食管下括约肌压力,分别于全身麻醉前置入压力感受器时（基础值）、气管插管前、气管插管后、改为侧卧肾体位时、气腹压力达15 mmHg时测量食管下括约肌压力及胃内压,计算食管跨障压.比较不同时间点的食管下括约肌压力及食管跨障压.结果 与麻醉前基础值相比,全麻气管插管前、气管插管后、侧卧肾体位后、CO2气腹中食管下括约肌及胃食管跨障压均降低（P＜0.05）.结论 食管下括约肌和胃食管跨障压在全身麻醉后降低,但在整个麻醉诱导和后腹腔CO2充气过程中胃食管跨障压保持正值.     

左心声学造影对二尖瓣狭窄跨瓣压的测量价值

目的　经静脉注射东冠注射液声学造影剂进行左心室声学造影 ,探讨其对二尖瓣狭窄跨瓣压的测量价值。方法　对 10例二尖瓣狭窄患者注射声学造影剂 0 .0 8ml/kg ,测量造影前后二尖瓣狭窄跨瓣压差并与心导管资料对比。结果　造影前后跨瓣压分别为 ( 13 .7± 4.6)mmHg及( 15 .5± 4.4)mmHg ,两者比较差异有显著性 (P <0 .0 5 ) ;造影后跨瓣压与心导管所测跨瓣压的相关系数为 0 .90 ,两者比较差异有非常显著性 (P <0 .0 0 1)。结论　声学造影可增加超声仪检查二尖瓣狭窄血流频谱的准确性。     

参麦注射液和氨茶碱对慢性缺氧大鼠膈肌细胞凋亡及相关基因表达的影响

目的　探讨参麦注射液和氨茶碱对慢性缺氧大鼠膈肌细胞凋亡及Fas/FasL基因蛋白系统表达的影响。方法　雄性Wistar大鼠 75只 ,随机分为空白组 (A组 )、参麦组 (B组 )和氨茶碱组 (C组 ) ,每组 2 5只 ,根据实验要求 ,3组再各分为缺氧前、缺氧 1周、2周、3周及 4周组 ,每组 5只。各组缺氧浓度均为 ( 10± 3 ) % ,7d/w ,8h/d ;B、C组在缺氧前分别注射参麦 ( 2ml/只 )、氨茶碱 ( 10mg/kg)。采用免疫组织化学及末端脱氧核苷酸转移酶介导的三磷酸脱氧尿嘧啶缺口末端标记 (TUNEL)法 ,检测各实验组Fas/FasL系统的表达及膈肌细胞凋亡 ,比较参麦和氨茶碱干预后对上述指标的影响。结果　 ( 1)A组膈肌细胞缺氧前Fas、FasL的表达阳性率分别为 ( 2 77± 0 45) %、( 2 3 2± 0 61) % ,缺氧后其表达随缺氧时间的延长而增加 ;经参麦干预后 ,B组在缺氧 1周、2周、3周、4周的Fas表达 [( 6 3 6±4 17) %、( 9 77± 4 12 ) %、( 18 0 2± 6 91) %、( 2 1 0 9± 8 0 9) % ]、FasL表达 [( 5 3 2± 6 16) %、( 9 58±3 79) %、( 12 0 1± 8 71) %、( 19 43± 10 3 1) % ]与A组同期比较差异有显著性 (P均 <0 0 5)。而氨茶碱对其表达的作用不明显 ,C组Fas表达 [( 10 87± 3 62 ) %、( 2 4 13± 3 79) %、( 3 5 3 9± 9 0     

内毒素对大鼠膈肌收缩功能及线粒体超微结构的影响

目的 观察内毒素(革兰阴性菌细胞壁的脂多糖成分)对大鼠膈肌收缩功能及线粒体超微结构的影响,为探索呼吸衰竭发生机制提供新思路.方法 将28只SD大鼠按随机数字表法分为:(1)对照组(10只)气管内灌注生理盐水;(2)实验组气管内灌注内毒素,浓度为200 ?g/ml,剂量为0.5 ml/kg,制备急性肺损伤(acute lung injury,ALI)动物模型,再分为观察4 h(内毒素4 h组,9只)及24 h(内毒素24 h组,9只)2组.然后,取膈肌肌条,用体外电生理方法测定膈肌的最大收缩力、颤搐收缩峰值及疲劳指数.另外取膈肌标本固定后做电镜检测.采用SPSS 15.0统计软件分析数据,组间比较用单因素方差分析及q检验.计量资料以x-±s表示.结果 (1)内毒素4 h组膈肌的收缩力及颤搐收缩峰值[(3.4 ±1.9)及(0.9±0.4)N/cm2,经肌肉横截面积校正]均明显低于对照组[(6.7±4.3)及(2.2±1.7)N/cm2,F值分别为3.59、3.78,P＜0.05];内毒素24 h组膈肌的收缩力及颤搐收缩峰值[(4.1±1.2)和(1.2±0.7)N/cm2]较内毒素4 h组明显恢复.(2)膈肌的疲劳指数在内毒素4 h及24 h组(分别为0.07±0.06和0.12±0.07)均较对照组(0.26±0.14)明显下降(F=9.27,P＜0.01).(3)内毒素4 h组及24 h组电镜下显示膈肌间线粒体肿胀、嵴减少,外膜模糊、变形,部分溶解破坏等超微结构的改变.结论 内毒素可导致ALI大鼠膈肌的收缩力下降并易于疲劳,这可能是导致呼吸功能衰竭的原因之一.     

川芎嗪注射液治疗结核性脑膜炎合并高颅压的临床观察

目的 观察川芎嗪注射液在治疗结核性脑膜炎合并高颅压中的作用.方法 随机将50例结核性脑膜炎合并高颅压病人分为常规组(对照组)和川芎嗪组(治疗组),每组25例.对照组给予抗结核、降颅压、激素及鞘内注药等常规治疗,治疗组在常规治疗的基础上加用川芎嗪注射液120 mg加入5%葡萄糖250 mL中静脉输注.每日1次,两组均以30 d为1个疗程.1个疗程后观察头痛消失时间、记录脑脊液压力恢复正常时间及临床疗效.结果 治疗组平均头痛消失时间为(11±3)d,对照组为(18±5)d(P＜0.01);脑脊液压力恢复正常时间为(23±4)d,对照组为(34±5)d,治疗组明显缩短(P＜0.01);治疗组显效率为72.0%,明显高于对照组的52.0%(P＜0.05).两组均未出现并发症及明显副反应.结论 在常规治疗的基础上,加用川芎嗪注射液治疗结核性脑膜炎合并高颅压,能更快地缓解临床症状,提高疗效.     

Effect of transdiaphragmatic pressure partitioning on activation and fatigue of the diaphragm

Fatiguing contractions of the diaphragm during inspiratory resistive loading are accompanied by a predictable rate of decay in the high/low (H/L) frequency ratio of the diaphragmatic EMG (EMG-DI) when the esophageal and gastric pressure (Pes and Pga) components of transdiaphragmatic pressure (Pdi) are equal. However, Pes and Pga do not contribute equally to Pdi under a number of clinical and physiologic conditions. We therefore tested the effect of varying the Pes and Pga contribution to Pdi on the EMG-DI using an esophageal electrode in 5 normal men during fatiguing contractions. Falls in the H/L occurred in all subjects regardless of the relative contribution of Pes and Pga to Pdi at a tension-time index of 0.29 +/- 0.1 (mean +/- SE). However, the time constant of decay of the H/L varied widely among subjects when Pes predominated (173.9 +/- 45.7 s; coefficient of variation, 58.7%) or Pga predominated (78.4 +/- 19.4 s; coefficient of variation, 55.2%), whereas it was consistent among subjects when Pes and Pga were equal (72.3 +/- 3.8 s; coefficient of variation, 11.6%). In addition, a significant relationship was found between the mean integrated activity of the EMG-DI compared with maximum and the time constant of decay of the H/L (r = 0.57, p less than 0.03). We conclude that the differences in the rate of decay of the H/L was at least partly a result of differences in the relative activation of the crural diaphragm at the same Pdi.     

Can diaphragmatic contractility be assessed by twitch airway pressures in patients with chronic obstructive pulmonary disease?

In healthy subjects and in patients without lung diseases, twitch airway pressure (Paw(tw)) responses to phrenic nerve stimulation can be used to predict twitch esophageal pressure (Pes(tw)) and twitch transdiaphragmatic pressure (Pdi(tw)), thus overcoming the need for placement of esophageal and gastric balloons. The aim of this study was to determine whether measurements of Paw(tw) combined with simple maneuvers could be used to predict Pes(tw), and possibly Pdi(tw), in patients with severe chronic obstructive pulmonary disease (COPD) (n = 12). Stimulations delivered at relaxed FRC produced a correlation coefficient (r) between Paw(tw) and Pes(tw) of 0.44 (p < 0.001) and of 0.62 (p < 0.001) during stimulations while patients performed a gentle exhalation from FRC. Stimulations performed during a gentle inhalation produced a good correlation between Paw(tw) and Pes(tw) (r = 0.92, p < 0.001); however, the limits of agreement between Paw(tw) and Pes(tw) were wide. Correlations between Paw(tw) and Pdi(tw) during the three experimental conditions were weak. In conclusion, during a gentle inspiratory effort in patients with severe COPD the correlation between Paw(tw) and Pdi(tw) was weak, whereas the correlation between Paw(tw) and Pes(tw) was good, but it was not sufficient to allow the prediction of Pes(tw) from Paw(tw) in all patients.     

Diabetic polyneuropathy is associated with respiratory muscle impairment in type 2 diabetes

Aims/hypothesis Diabetes has a major negative effect on intensive care unit outcome. This has been partly attributed to impaired respiratory neuromuscular function. However, data on respiratory neuromuscular involvement in diabetes are lacking. This study therefore aimed to assess respiratory neuromuscular function related to diabetic polyneuropathy in patients with type 2 diabetes. Methods Respiratory neuromuscular function was assessed by the use of volitional tests and twitch mouth (TwPmo) and twitch transdiaphragmatic (TwPdi) pressures during non-volitional bilateral anterior magnetic phrenic nerve stimulation in 21 male type 2 diabetic patients without pulmonary disease and in 23 healthy, well-matched controls (forced expiratory volume in 1 s 103 ± 11 vs 103 ± 12% predicted; p = 0.9). Results Both volitionally assessed maximal inspiratory and expiratory mouth pressures, and sniff nasal and transdiaphragmatic pressures were comparable between diabetic patients and controls (p > 0.1 for all). TwPmo was reduced in diabetic patients compared with controls (1.3 ± 0.5 vs 1.0 ± 0.4 kPa; p = 0.04), while TwPdi was comparable (1.7 ± 0.5 vs 1.6 ± 0.7 kPa; p = 0.6). Following subgroup analysis, patients with no or mild polyneuropathy (n = 10) as assessed by neurological disability scoring had normal respiratory neuromuscular function, whereas patients with moderate or severe polyneuropathy (n = 11) presented with markedly impaired respiratory neuromuscular function as indicated by TwPmo (1.3 ± 0.4 vs 0.8 ± 0.3 kPa; p = 0.01) and TwPdi (1.9 ± 0.6 vs 1.1 ± 0.4 kPa; p < 0.01). Conclusions/interpretation With regard to volitional tests, diabetes does not affect respiratory neuromuscular function. In contrast, the application of non-volitional phrenic nerve stimulation provides strong evidence that diabetic polyneuropathy, as simply assessed by neurological disability scoring, is associated with substantially impaired respiratory neuromuscular function in type 2 diabetic patients.     

Variability of electrophrenic diaphragm twitch stimulation over time in normal subjects

Transcutaneous electrophrenic twitch stimulation is a potentially powerful way to assess diaphragm contractile function in response to interventions which may alter respiratory muscle strength and endurance. At present, the variability of the transdiaphragmatic twitch pressure (Pdi(T)) over a several hour period is not well described. The present study examines the reproducibility of Pdi(T) amplitude and the twitch occlusion technique of assessing maximum transdiaphragmatic pressure (Pdi(max)) in seven normal adults stimulated intermittently every hour for a total 4-h period. In one subject, data were obtained on two occasions separated by a 2-month interval. Among all subjects, the Pdi(T) amplitude expressed as a percentage of the Pdi(max) was highly reproducible over 4 h (coefficient of variation 5.3). Peak Pdi(T) was inversely related to graded voluntary Pdi (r = -0.0996) and the relationship was virtually identical over 4 h (r = - 0.999, P = 0.96). These data show that Pdi(T) at functional residual capacity and the twitch occlusion relationship are highly reproducible.     

"Intrinsic" positive end-expiratory pressure in stable patients with chronic obstructive pulmonary disease

We have assessed "intrinsic" positive end-expiratory pressure (PEEPi), during quiet breathing in 18 patients with chronic obstructive pulmonary disease (COPD) in stable condition. Ventilatory flow, lung volume, oesophageal (Poes), gastric (Pga), and transdiaphragmatic pressure (Pdi) were measured. PEEPi was measured as the pressure difference (delta Poes) between the onset of the inspiratory effort, indicated by the start of the Pdi swing, and the point corresponding to zero flow. PEEPi was present in all of the 18 COPD patients, and averaged 2.4 +/- 1.6 cmH2O. The maximum transdiaphragmatic pressure (Pdi,max) was also measured and averaged 81.5 +/- 17.4 cmH2O. Following a randomized sequence, ten patients then inhaled an adrenergic agonist (fenoterol 1.6 mg), and eight patients the corresponding placebo. Fenoterol, but not placebo, caused a significant increase in forced expiratory volume in one second (FEV1) (+34%, on average), associated with a significant decrease in PEEPi (-63%, on average) and a significant improvement in Pdi,max (+19%, on average). We conclude that: 1) intrinsic PEEP can be present in stable COPD patients due to increased airflow resistance; 2) fenoterol improved diaphragmatic strength (Pdi,max) in our COPD patients, possibly due to a decrease in lung volume.     

Diaphragm strength in chronic heart failure.

Reduced respiratory muscle strength has been reported in chronic heart failure (CHF) in several studies. The data supporting this conclusion come almost exclusively from static inspiratory and expiratory mouth pressure maneuvers (MIP, MEP), which many subjects find difficult to perform. We therefore performed a study using measurements that are less dependent on patient aptitude and also provide specific data on diaphragm strength. In 20 male patients and 15 control subjects we measured MIP and MEP as well as esophageal and transdiaphragmatic pressure during maximal sniffs (Sn Pes, Sn Pdi) and cervical magnetic phrenic nerve stimulation (Tw Pdi). In a subgroup the response to paired phrenic nerve stimulation (pTw Pdi) at interpulse intervals from 10 to 200 ms (5 to 100 Hz) was also determined. As expected, MIP was significantly reduced in the CHF group (CHF, 69.5 cm H(2)O; control, 96.7 cm H(2)O; p = 0.01), but differences were much less marked for Sn Pes (CHF, 95.2 cm H(2)O; control, 104.8 cm H(2)O; p = 0.20) and MEP (CHF, 109.1 cm H(2)O; control, 135.7 cm H(2)O; p = 0.09). Diaphragm strength was significantly reduced (Sn Pdi: CHF, 123.8 cm H(2)O; control 143.5 cm H(2)O; p = 0.04. Tw Pdi: CHF, 21.4 cm H(2)O; control, 28.5 cm H(2)O; p = 0.0005). Paired phrenic nerve stimulation suggested a trend to increased twitch summation at 5 to 20 Hz in CHF, although this did not reach significance. We conclude that mild reduction in diaphragm strength occurs in CHF, possibly because of an increased proportion of slow fibers, but overall strength of the respiratory muscles remains well preserved.     

Respiratory pressure partitioning during quiet inspiration in unilateral and bilateral diaphragmatic weakness

To compensate for diaphragmatic weakness, intercostal/accessory muscles may be recruited in inspiration and/or abdominal muscles in expiration with relaxation during subsequent inspiration. As a consequence, for a given decrease in pleural pressure (Ppl) during quiet inspiration (qi), abdominal pressure (Pab) should either undergo a smaller increase than normal or, in severe cases, decrease. If so, the ratio of change in Pab to Ppl during qi (delta Pab/delta Ppl(qi], which is normally less than -1 when upright, should increase, approaching +1 in profound diaphragmatic weakness. To examine the relationship between degree of diaphragmatic weakness and delta Pab/delta Ppl(qi), we measured (erect and supine) anteroposterior rib cage and abdominal motion, Pab, Ppl, and transdiaphragmatic pressure (Pdi) during qi, maximal inspiration (Pdi(max)mi) and maximal inspiratory effort at FRC (Pdi(max)FRC) in 10 patients with bilateral and 8 with unilateral diaphragmatic weakness. Pdi(max)mi and Pdi(max)FRC were low in all patients. delta Pab/delta Ppl(qi) (erect) was increased in all patients (0.28 +/- 0.7; mean +/- SD) and correlated closely with both Pdi(max)mi (r = -0.89, p less than 0.001) and Pdi(max)FRC (r = -0.76, p less than 0.001). There was extensive overlap in the data between unilateral and bilateral diaphragmatic weakness. The ratio of delta Pdi during qi to Pdi(max)FRC was less than 0.31 in all patients. The results suggest that delta Pab/delta Ppl(qi) is a useful index of the degree of diaphragmatic weakness and that the functional consequences of unilateral and bilateral weakness are not rigidly separable.(ABSTRACT TRUNCATED AT 250 WORDS)     

Influence of maturation on infant diaphragm function assessed by magnetic stimulation of phrenic nerves

Infant diaphragm function may be adversely affected in a variety of disorders and conditions. Key to establishing an accurate diagnosis are appropriate control data. The aim of this study was to determine the effect of maturation on diaphragm function, using a nonvolitional test. Diaphragm function was assessed by measuring the transdiaphragmatic pressure (Pdi) generated by magnetic stimulation of the phrenic nerves. Ballon catheters were positioned in the lower third of the esophagus and stomach. Esophageal (Pes) and gastric (Pgas) pressure changes were measured using differential pressure transducers. The pressure signals were amplified and displayed in real time on a computer (running Labview trade mark software) and Pdi derived by online subtraction of Pes from Pgas. Twenty-nine infants (14 born preterm), at a median gestational age of 37 (range, 25-42) weeks, were studied at a median postconceptional age (PCA) of 39 (range, 32-44) weeks. At time of measurement, none had respiratory problems or were hyperinflated (functional residual capacity ranged from 23-35 mL/kg). The preterm infants had significantly lower transdiaphragmatic pressures responses following median left (4.0, range 2.5-6.8 cmH(2)O vs. 4.8, range 2.8-7.2 cmH(2)O) and median right phrenic nerve stimulation (3.6, range 2.6-4.8 cmH(2)O vs. 4.3, range 2.7-6.8 cmH(2)O) (P < 0.05) than term infants. Following left and right phrenic nerve stimulation, Pdi correlated significantly with gestational age (r = 0.4, P < 0.05, and r = 0.4, P < 0.05, respectively) and PCA (r = 0.37, P = 0.05, and r = 0.56, P < 0.01, respectively). We conclude that gestational age at birth and postconceptional age at time of measurements must be taken into account when interpreting the results of infant diaphragm function tests.     

Diaphragm function after pulmonary resection. Relationship to postoperative respiratory failure

We studied the lung mechanics and respiratory muscle function in 20 patients undergoing pulmonary resection. Transdiaphragmatic pressure (delta Pdi) during quiet breathing did not show any remarkable change after the operation (9.5 +/- 1.1 to 10.9 +/- 1.0 cm H2O), while the ratio of abdominal to transdiaphragmatic pressure changes (delta Pab/delta Pdi) revealed a significant difference between the preoperative and the early postoperative periods (0.32 +/- 0.06 to 0.00 +/- 0.11, p less than 0.05). The postoperative delta Pab/delta Pdi correlated significantly with the work of breathing (r = -0.60, p less than 0.01). The maximal transdiaphragmatic pressure (Pdimax) decreased significantly after operation (75.0 +/- 15.8 to 32.8 +/- 12.4 cm H2O, p less than 0.05), with no significant change in the maximal inspiratory mouth pressure (MIP) (74.2 +/- 16.8 to 39.5 +/- 11.6 cm H2O). Four of 20 patients developed respiratory failure postoperatively and required mechanical ventilation. delta Pab/delta Pdi in these patients was significantly lower than in the other patients (-0.62 +/- 0.24 versus 0.16 +/- 0.09, p less than 0.005). Our results suggested that during quiet breathing diaphragmatic function was preserved and intercostal/accessory muscles recruitment increased, but maximal strength of the diaphragm might be reduced in patients undergoing pulmonary resection.